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THE RELATIONSHIP BETWEEN ISOKINETIC HIP STRENGTB AND CLOSED KINETIC PERFORMANCE IN ELITE HOCKEY PLAYERS
A. Jason Kea School of Physical Therapy
Submitted in partial Mfilment of the requirements for the degree of
Master of Science
Faculty of Graduate Studies The University of Western Ontario
London, Ontario April, 1999
'A, Jason Kea 1999
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Abstract
The purposes of the study were to examine: 1) the test-retest reliability of isokinetic hip
abductor and adductor peak torques; 2) the test-retest reliability of one-legged hop tests in
the medial and lateral directions; and 3) the reeltiomhip between hip muscle strength and
the hop tests. The dominant leg of 27 elite male hockey players was tested on two
occasions, at least 72 hours apart. Isokinetic testing was performed on a computerized
dynamometer (Kin-Corn) at 60°fsec using concentric-abduction, eccentric-abduction,
concentric-adduction, and eccentric-adduction movements. The one-legged hops were
tested in the medial and lateral directions. The Intraclass Correlation Coefficients (KC)
for the isokinetic tests were modest for data collected on one test occasion (ICC 2,1=
0.59 to 0.74) and generally excellent for data averaged over two test occasions (KC 2 J =
0.74 to 0.85) suggesting that two test occasions are desirable to maximize reliability. The
ICCs for the lateral and medial hops were excellent (KC 2,1= 0.91 and 0.87) for one test
occasion. The correlations between the strength and hop tests were poor (r = 0.01 to 0.27,
p > 0.05) supporting previous suggestions that function can not be predicted by joint
specific strength testing. Clinicians must be careful not to assume a strong relationship
between joint specific isokinetic tests and hction.
Key words: Isokinetic hip strmgth, functional test, rehability
ACKNOWLED(rEMENTS
I would like to thank John Kramer, Lorie Forwell, Trevor Birmingham, Pat
Darling, Marg Lee, Donna Beer and Tony Vandervoort for their assistance with this
project Their guidance, critical appraisal, and support during this undertaking made it
possible.
Also many thanks are extended to my parents, sister and friends. Family and
friends are the Cornerstone to any person's life. Without their attentive ears and ongoing
support, I would have never undertaken this adventure. You are always in my heart.
CONTENTS
CERTIFICATE OF EXAMINATION / ii ABSTRACT / iii ACKNOWLEDGEMENTS / iv TABLE OF CONTENTS / v LIST OF TABLES / vi LIST OF FIGURES / vii
Page
............................................ CHAPTERlINTRODUCTION 1
Purposes ........................................................ 10
................................................. CHAPTER 2 METHODS 11
Subjects ........................................................ 11
........................................... Muscular Strength Tests 17 ................................................. A) Test Position 17
.................................................. B)StrengthTest 19
..................................................... Conclusions 39
APPENDICES ......................................................... 41
........................................................ REFERENCES 56
LIST OF TABLES
Table Description
1 . Subject descriptive infomation ..................................... -13
2 . Reliability of the isokinetic hip strength tests .......................... -24
......................................... 3 . Reliability ofthe hop tests -25
4 . Mean and standard deviation (SD) of the strength and hop tests ............. 26
5 . Two way ANOVA for movements (abduction and adduction) by muscle actions .......................................... (concentric and eccentric) 27
6 . Paired t-test comparison of distance hopped in the lateral and medial direction ..................................... (values are for difference scores) 28
........................ 7 . Correlations (r) between strength and hop scores 29
LIST OF FIGURES
Figure Description Page
1. Hop test for distance performed in the medial direction. . . . . . . . . . . . . . . . . . . . 14
2. Positioning for the isokinetic hip abduction and adduction tests: posterior view. 15
3. Positioning for the isokinetic hip abduction and adduction tests: Lateral view. . . 16
INTRODUCTION
The hip joint forms an important connection between the lower extremity and the
trunk that is intricately involved in the process of ambulation and other transitional
movements (ie. squatting, power skating). However, few studies have examined hip
strength or test-retest reliability and how hip strength relates to function. Test-retest
reliability articles involving lower extremity measures have primarily focused on the knee
and ankle joints. There are only a few articles that have reported the tat-retest reliability
of measures associated with the hip joint (Vaz et a1 199 1, Burnett et al1990, CahaIan et
a1 1989).
Hockey players are characterized by a high incidence of musculotendinous non-
contact hip injuries, such as muscular strains of the groin, hamstrings, iliopsoas and
quadriceps femoris musculature (Gooch et a1 1993, Age et al 198 8, Roberts and
Williams 1988). It has been suggested that these injuries are the result of the high
acceleration and deceleration in hockey skating combined with the dynamic stability
requirements on the ice surface (Agre et a1 1988, Sim et a1 1987). Although these injuries
result in considerable loss of playing time, there has been little Investigation to date to
evaluating the severity of these muscular dysfbctions.
In the rehabilitation setting, determining readiness to retum to sport and more
complex skills in hockey players have often used open kinetic chain testing, such as
isokinetic strength testing (Peachnig et a1 1998, Shelboume and Nitz 1995, Seto et a1
1988). Open kinetic chain exercises for the lower extremity have been defined as activity
that occurs while the foot is firee to move, such as isolated isokinetic seated knee
extension and isokinetic ankle plantar flexion performed in the kneeling position
@inningham et a1 1998, Stuart et a1 1996, Wi et a1 1996, Palmitier et a1 1991).
Closed kinetic chain activities have been developed as an additional means to
prepare and evaluate a patients ability to retum to a higher fuactioaal Level taking into
account specificity of training principles (Petschnig et al1998, Greenberger and Paterno
1995, Risberg and Ekland 1994, Lephart et af 1992, Anderson et all99 1, Shelboume and
Nitz 1988, Daniel et a1 1982)- These activities have been defied as activity peflormed
while the foot is fixed and hip motion is accompanied by knee and ankle motion, such as
during a standing squat or during the ice contact component of the skating motion
(Birmingham et a1 1998, Stuart et a1 1996, Wilk et a1 1996, Palmitier et al 199 1).
Several authors have agreed that lower ememity functional tests, which are
defined as those that simulate the stresses on the joints which occur during sports, are a
valuable tool in the assessment of the athlete's ability to participate in sport (Lephart et a1
1992, Noyes et a1 199 1, Barber et a1 1990, Tegner et a1 1986, Daniel et al ; 982). The
ease and Iow cost of performing functional tests makes them ideal for use in clinical
settings (Vandenneulen et a1 1999, Noyes et a1 199 1, Daniel et al 1988).
There is an abundance of literature penaining to lower extremity closed kinetic
activities. Among those investigated are the single leg hop for distance, (Petschnig et a1
1998, Noyes et a1 199 1, Barber et a1 1990, Daniel et a1 1988, Tegner et a1 1986), the one-
legged cross-over hop for distance (Wik et a1 1994), the one-legged lateral hop
(Vandermeulen et a1 1999), and two legged tests that include the figrue-of-eight test
3
(Petscbnig et al1998, Risberg and Ekland 1994,Tegner et a1 1986) , the stair-rumkg test
(Petschnig et al1998, Risberg and Ekland 1994,Tegner et al1986), the carioca test which
involves crossing one leg over in a sideways direction (Petschnig et a1 1998, Lephart et a1
1992), and the vertical jump (Petschig et a1 1998, Anderson et a1 1991, Barber et aI
1990). The majority of these movements concentrate on forward or vertical movements
and do not take into account the lateral destabilizing forces involved in direction changes,
such as cutting.
Before tests that evaluate hip muscular injuries can be used comparatively, or
studied for significance and validity, knowledge of their test-retest reliability is required
(Fleiss 1986). Similarly, in order for hip tests to be used clinically to make confident
decisions regarding an individual's progress with treatment, knowledge of the day-to-day
variability in individual scores is necessary. Whereas reliability coefficients such as the
intraclass correlation coefficient (ICC) quantify systematic error for a group of
individuals, the standard error of measurement (SEN provides a means of quantifying
the between-session variability of an individual's scores. Using the SEM, 95%
confidence in te~a ls (CI) can be constructed ar0u11d an observed score, and this quantifies
the range within which the true score might be expected to vary as a result of
measurement error (Streiner and Norman 199 1). Because clinicians are often faced with
relatively small changes in the strength of their patients, it is important that they know
whether these changes are or are not attributable to measurement error (Stratford 199 1).
Both open and closed kinetic chain activities were used in the present study to
evaluate strength and function around the hip joint. Specifically, isokinetic hip abduction
4
and adduction movements performed concentrically and eccentrically represent open
kinetic chain activities, while one-legged hops performed in the medial and lateral
directions represented closed kinetic chain activities.
Hip abduction and adduction contribute to the n o d mechanics in power
skating. The skating motion is initiated when the skater forcibly abducts the thigh in the
push off movement and then rapidly shifts their weight to the opposite leg to initiate the
glide stroke (Humble and Gastwirth 1988, Merrifield and Cowan 1973). These motions
along with hip and knee extension contribute to the ice skating motion used in hockey.
The actions of crossing one leg over the other to change direction and stopping in a lateral
direction are also hypothesized by the present authors to involve hip abduction and
adduction movements. The current literature includes several articles related to isokinetic
evaluation of the hip abductor and adductor movements (Donatelli et a1 1991, Bumett et
al1990, Cahalan et a1 1989, Ryser et a1 1988, Tippett 1986, Poulmedis 1985, Markhede
and Grimby 1980, Molnar and Alexander 1979, Jensen et a1 197 1, May 1968, Murray and
Sepic 1968, Merchant 1965). Although these studies provide comparative information
for a number of populations, information pertaining to the reliability of isokinetic testing
of hip abduction and adduction movements is Limited (Burnett et al1990, Cahalan et a1
1989)-
Bumett et a1 (1990) studied the test-retest reliability of six isokinetic hip
movements completed by healthy young boys aged 6 to 10 years. The 29 subjects were
tested on two occasions with 1-2 weeks between test sessions. The tests were performed
in the standing position. Although the authors did not report whether the measures were
concentric or eccentric, the date of the paper and the use of the Cybex I1 suggest
concentric muscle actions. Reported ICCs for hip abduction and adduction movements
performed at 30" and 90°/sec angular velocities were considerably Iowa than those
reported for hip flexion, extension, medid and lateral rotation movements. Their hip
abduction and adduction ICC values ranged fbm 0.49 to 0.59. The authors amiuted the
poor reliability of the peak torques to the difficulty in testing the young age group,
inability to standardize joint range of motion (ROM), inadequate practice sessions and
poor stabilization. Although the specific type of ICC calculated was not stated, using the
reported ICCs and standard deviation values, an estimate of the variation in an
individual's score can be obtained. Specifically, using the calculation described by
Streiner and Norman (1991) the SEM and 95% CI for the reponed scores obtained during
hip abduction and adduction tests performed at 30°/sec can be determined. The SEMs of
t3 and *6 Nm suggest that an individual's true score could vary *6 and *11 Nm (95%
CIS) between test sessions for abduction and adduct ion movements, respectively.
Cahalan et a1 (1989) also investigated the six major hip movements and measured
isokinetic strength. Their testing protocol involved a Cybex II isokinetic dynamometer,
and subjects were stabilized in an upright (standing) fhme designed for the study. The
peak torques produced by the 72 healthy subjects aged 20-8 1 years of study were
recorded. Among these subjects, 18 young men (man age = 28 years) and 17 older men
(mean age = 54 years) participated in the study. Thirteen other normal individuals were
recruited for a separate test-retest pilot study. Although, methodological details were not
included in the article, the authors reported that in the two day pilot the mean difference
6
in the peak torque values was less than 4% for all fimctions and a test-retest correlation of
0.96 was reported The type of correlation used to determine this value was not
described, but it is much higher than the KC'S reported by kumett et a1 (1990).
Vaz et a1 (199 1) investigated the test-retest reliability of hip abductor strength in
twenty three male and twenty female subjects. However, unlike Burnen et a1 (1990), the
strength measures reported were isometric and the subjects were patients measured pre
and post total hip joint replacements. That study revealed that the isometric method of
evaluation was highly reliable (KC 2,l r 0.97) using a test-retest protocol completed on
one occasion with a 30 minute rest between tests. Using the Streiner and No- (1991)
calculation it is estimated that the SEM values for the hip abduction peak torques would
range fonn 2 to 3 Nm and the 95% CI would range fiom 4 to 6 Nm. These values are
based on the mean and standard deviations of the peak torques reported in a Vaz et a1
(1 99 1) bar graph. Another aspect of the study involved correlating the isometric torques
with a fimctional disability scale and a six minute walk test. The relationship between hip
abductor torques and the functional disability scale was low and non significant (r = -0.17
to -0.26, p > 0.05). However, the relationships between hip abductor torques and the six
minute walk was moderate and statistically significant (r = 0.48 to 0.5 1, p < 0.01).
Several other studies of isokinetic hip strength did not use test-retest protocols.
Donatelli et a1 (199 1) studied isokinetic hip abductor and adductor peak torques
completed at an angular velocity of 6O0/sec in 42 healthy subjects (mean age = 26 years)
using a MERAC system. The subjects were positioned in side lying facing away fiom the
dynamometer. The axis of rotation was aligned 0.5 inches medial to the anterior superior
7
iliac spine (ASIS) and the end of the Lever arm positioned at the lateral joint line of the
knee. Although, the type of contraction investigated was not mentioned, the age of the
paper (1 99 1) and the use of the MERAC isokinetic dynamometer suggest concentric
muscle actions. The relationship between abductor and adductor torque was investigated
by the authors and expressed in a ratio. The ratios reported suggest that the adductor peak
torques were larger than the abductor peak torques.
Two recent studies investigated the hip strength in athletic populations. Steven
Tippett (1 986) performed a pilot study that examined the hip, knee and ankle peak
torques during concentric muscle actions and the range of motion of 16 college baseball
pitchers (mean age = 20 years). Side lying hip abduction and adduction isokinetic peak
torques were measured on both legs at 30° and 1 80°/sec angular velocities. Each lower
limb was classified as either the stance or the kick leg depending on the biornechanical
function during the pitching motion. Five repetitions were pwfomed at the 30°/sec
angular velocity and 15 repetitions at the 180°/sec angular velocity. Thirty seconds rests
were given between testing speeds and a 2-minute rest between the test movements. The
test position, stabilization, and instructions used were not specified. Only two
submaximal practices were given prior to the testing. The results indicated that there was
no statistically significant differences between the stance and kick legs when hip
abduction and adduction peak torques were compared.
Another study involving athletes was performed by Poulmedis (1985). He
measured peak torques during concentric muscle actions in 18 elite Greek soccer players
(mean age = 28 years). Hip abduction and adduction peak torques were measured using
8
the Cybex I1 isokinetic dynamometer- The authors reported the patients were set up in the
standard position described in the Cybex I1 manual. Mean peak torque values and a 74%
ratio of the hip abductor to adductor peak torques were reported. This finding supports
the Donatelli et a1 (1991) finding that the adductor peak torques are higher than the
abductor torques.
The only study located by the present author that evaluated a pathological
population using isokinetic hip testing was performed by Ryser et a1 (1988). They
studied individuals having undergone above knee amputations (AKA), by comparing
peak torques during hip abduction movements at 30°, 90" and 150°/sec angular velocities
in prosthetic and intact limbs. The subjects were 8 male patients and 2 female patients
(mean age = 41 years) matched to 10 healthy individuals (mean age = 42 years).
Abduction peak torques during concentric muscle actions were 47 Nm and 76 Nm for the
prosthetic and intact Limbs respectively. Abductor strength was investigated due to the
importance of the musculature in maintaining a level pelvis during the single leg stance
phase of gait. The authors proposed changes in stabilization and positioning of the pelvis
and limb as possible improvements in study desige
Along with isokinetic testing, functional tests that involve the hip joint have been
under represented in the literature. Vandenneulen et a1 (1999) recently studied a one-
legged lateral hop test thought to produce lateral destabilizing forces that were similar to
cutting and landing off balance. This test-retest study was performed using 46 healthy
young subjects (mean age = 2 1 years). The reliability coefficients on one test occasion
were excellent (ICC 2,1 r 0.83), inferring that the lateral hop test could be used to
9
determine differences in a pathological populations. SEMs and 95% CIS of * 8 cm and * 15 cm respectively were reported for the 17 males tested (mean age = 22). Vandermeulen
et a1 (1999) did not perform a one-legged medial hop test. A subject's o v e d ability to
change direction can be better evaluated by including a hop for distance in both the IateraI
and medial directions-
The ease and low cost of perfionning the hop test for distance in the medial and
Iateral direction may also be beneficial in determining clinical return to sport parameters.
However, we were unable to find any articles that evaluated the relationships between
isokinetic strength and closed kinetic tests that focus on the hip abductor and adductor
movements. I fa strong relationship exists between the hop tests and the isokinetic
strength of the hip abductor and adductor movements, inferences regarding a hockey
players strength may be determined using a timely and cost effective hop tests.
Several studies have exambed the correlation between isokinetic strength and
closed kinetic performance in the knee (Petscbnig et ai 1998, Oreenberger and Patemo
1995, W i et a1 1994, Anderson et a1 199 1, Seto et a1 1988). Wilk et a1 (1994) studied
the single-leg cross-over triple hop for distance (SLCH), which involves lateral
destabilizing forces similar to those in the lateral and medial hops for distance. They
evaluated the inter-relationships among isokinetic quadriceps peak torques and three
functional hop tests in 50 subjects (mean age = 25 years) that had undergone arthroscopic
anterior cruciate ligament reconst~ction. Peak torques were assessed using a Biodex at
angular velocities of 1 80°, 300" and 450°fsec. There were significant Pearson product
correlations between the quadriceps peak torque and the SLCH at 180° (r = 0.69, p <
LO
0-01), 300' (r = 0.64, p < 0.01), and45O0lsec (r=0.53, p <O-05). The authors discussed
that correlations exist between bctional and isokhetic tests, but did not mention the
ability of the strength tests to predict functional ability.
The moderate correlation values reported by Wilk et a1 (1994) and other studies
(Petschnig et al1998, Greenberger and Patemo 1995, Anderson et a1 199 1, Set0 et a1
1 9 8 8) suggest that knee functional performance may not be adequately predicted by the
use of isokinetic suength testing alone. As a result, additional measures of lower limb
performance should be evaluated.
Purposes
The purposes of the present mdy were to examine : 1) the test-retest reliability of
hip abductor and adductor peak torques determined isokinetically during concentric and
eccentric muscle actions; 2) the test-retest reliability of one-legged hop tests in the medial
and lateral directions; and 3) the reiationship between hip muscle strength and the hop
tests in a group of elite hockey players.
CHAPTER 2
METHODS
Subjects
Twenty-seven healthy young males volunteered to be subjects for the study (Table
I), which had been approved by the University of Western Ontario's Health Sciences
Research Committee (Number E626 1 - Appendix A). The subjects were elite amateur
and professional hockey players fkom the following levels of hockey: Ontario West Junior
B; Ontario Hockey League Junior A; CIAU University of Western Ontario; and East
Coast League professional hockey. The subjects reported themselves to be free h m
major injury to the low back, pelvis, hip, knee and ankle over the past three years. A
major injury was defined as requiring the use of crutches or resulting in lost playing time.
Any subject with vertigo, decreased balance control, inner ear difficulties or major
neurological deficit was excluded from the study. AU subjects received an information
letter and were required to sign a form of consent prior to participation in the study
(Appendix A).
Test Protocol
Each subject performed the testing procedures (hop and strrngth tests) on two
separate occasions with a minimum of three days rest between occasions. All subjects
participated in a five minute pre-test information session when they first came to the
Muscular Assessment Lab. This included receiving a typed information letter that
described the purpose and procedures of the study, length of time required, physical risks
involved, advised them of their right to withdraw, and described subject anonymity
12
(Appendix A). They also completed an information sheet to aquire demographic data,
and potential exclusion criteria were discussed (Table 1). Testing commenced following
signing of an informed consent form (Appendix A). Participants were required to attend
the test sessions wearing shorts and nmning shoes, and to use the same apparel while
performing the tests on each occasion.
Following, consent the subjects rode on a cycle ergometer and performed three
specific stretches for the hip abductor and adductor musculature (pixiformi-s, iLioh'bial
band, and groin stretch) as a warm-up and in an effort to minimize the risk of physical
discomfort post-testing . Each subject determined their own comfortable rate of pedal
revolutions and resistance to perform a moderate intensity warm-up on the ergometer.
The subjects peddled for five minutes. The warm-up period was standardized for all
participants on both occasions.
Standardized verbal and visual instruction for the strength and hop testing were
given on both occasions (Appendix B). AlI the tests were performed with the dominant
lower extremity, defined as that used to kick a ball - test leg. AU tests were completed by
the same tester and assistant. The order of hop and strength tests was randomly assigned
for each subject
Hop Tests
All subjects performed a one leg hop test in both the medial and lateral directions
(Figure 1). The order of the hop direction was randomized and kept consistent for both
occasions, and all hops were completed in one direction before completing the hops in the
other direction. The subjects completed six practice hops which included three maximal
Mean SD --
Age - 20.2 2-7
Height (em) 181.6 5.3
Weight (kg) 83 -5 7.4
Experience Level Number of Hockey Playem
CIAU 13
Western Junior B 10
Ontario Hockey League 1
Professional 3
TABLE 1. Subject descriptive information (n = 27).
FIGURE 2. Positioning for the isokinetic hip abduction and adduction tests: posterior view*
FIGURE 3. Positioning for the isokinetic hip abduction and adduction tests: lateral view-
17
practice hops prior to data acquisitiom Each test consisted of three maximal hops. A
starting Line was marked on the tile floor with white tape. Subjects were instructed to hop
to their maximum distance, beginning on the test leg and landing on the same leg and
ensuring they maintained their balance on landing for five seconds. Any of the following
was considered a loss of balance: movement of the test foot on landing; touching down
with the opposite foot; and the use of either hand to maintain position. If balance was not
sufficiently maintained, the test was repeated until three measurements were obtained for
each occasion. The subjects' arms were f ie , allowing them to assist with balance and to
gain momentum in the jump. The distance hopped was immediately marked by a piece of
masking tape, measured and then removed prior to the next hop. The distance for the
medial hop was recorded from the lateral aspect of the foot on the starting line to the
point on the lateral aspect of the foot closest to the starting line on completion of the hop.
The distance of the lateral hop was recorded in the same manner using the medial aspect
of the foot as the marking point. The subjects were given 30 seconds rest between each
hop and three minutes of rest between the hop directions. Subjects were not informed of
their results during testing and no reference markers were placed on the floor.
Muscular Strength Tests
A) Test Position
The Kinetic Communicator (Kin-Corn, Model 500-H, Chattecx Corp, TN)
isokinetic dynamometer was used to collect the hip abductor and adductor strength data
throughout the study. Each subject was positioned in side lying on a adjustable
mobilization table (Figures 2 and 3). They faced the dynamometer head of the Kin-Corn
with the test leg positioned uppermost. One or two pillows were provided for under the
patient's head to maintain horizontal alignment of the head and trunk The subject's test
leg was uppermost and the hip and knee angles were at 0° of extension with neutral
rotational alignment. The non-test leg was positioned in approximately 30° hip flexion to
avoid contact with the test leg during adduction movements.
The axis of rotation of the hip joint was determined by land marking
approximately I cm medid to the anterior superior iliac spine (Donatelli et a1 1 99 1).
This axis was aligned co-axially with the rotational axis of the dynamometer head. In
order to achieve the proper axis alignment the subject was moved horizontally to the head
or foot of the bed and/or the mobilization bed moved vertically up or down. A circular
pad (1 0 cm diameter) was placed in fiont of the dynamometer axis to provide additional
pelvic comfort and stability.
The subjects were stabilized by two, 10 cm velcro straps secured around ihe
proximal aspect of the non-test thigh and around the waist just proximal to the iliac crest.
Two towels were placed under the waist strap on the upper lateral thorax to m h h k e any
discomfort. The subject was asked to hold onto the plinth with the upper arm during the
testing. The lateral femoral condyle was palpated and the end of the dynamometer arm
was positioned 2-3 cm proximal to this position. The exact position of the dynamometer
arm was determined by moving the test leg through the I11 range of motion @OM). The
position chosen for testing was the one that allowed the dynamometer resistance pad to
remain at the same position along the thigh during movement of the test leg without
sliding along the thigh. The dynamometer arm was secured with straps around the test
leg. The neutral position of the hip was determined using a goniometric measurement
and the Kin-Corn system was cali'brated to the subject's neutral (0") position. During
testing the examiner applied horizontal force to the posterior aspect of the sacrum, in h e
with the hip/shoulder pad, to offer f.urther stability-
Gravity correction was calculated for each test leg and used to determine peak
torque. The subjects weight was taken h m the information sheet and multiplied by 16
% to determine the approximate weight of the lower extremity (Plagenhoef et aI 1983).
This value was manually entered into the dynamometer at the time of gravity correction.
B) Strength Test
Isokinetic strength tesfing was completed at 60°/s angular velocity using the
following muscle actions and movements: 1) concentric-hip abduction; 2) concentric-hip
adduction 3) eccentric-hip abduction; and 4) eccentric-hip adduction. Peak torques were
measured in Newton meters (Nm) torque. The order of the test muscle actions and
movements was randomized on the !3st occasion, and kept consistent for both occasions.
The concentric and eccentric hip abduction were performed through a ROM of So
adduction to 30" abduction, while the concentric and eccentric hip adduction tests were
performed through a ROM of So adduction to 35" abduction.
Following verbal explanation of the isolcinetic test movements and the procedure,
a warm-up of seven repetitions was completed. Four of the warm-ups were completed at
submaximal intensity and three were completed at maximal effort, as practice
movements. The strength tests consisted of three single repetition maximal efforts in the
direction of the test movement The subjects were given 30 seconds rest between each
20
effort (including practice) and three minutes of rest between the strength tests. Subjects
were not informed of their results during testing- Standardized verbal instructions were
given between every warm-up and test repetition (Appendix B).
Data Analysis
All of the peak torque data were generated using the Kin-Corn's computer (En-
Corn 500-H, Chattecx Carp, 19894992, Software Version 3.2 1). The hop distance was
determined by the investigators using a tape measure and recorded Peak torque (Nm)
and distance hopped (m) were determined for each repetition and averaged to produce
one single measure for each occasion. Intracass Correlation Coefficients (ICCs) were
calculated to describe the reliability ofone (KC 2,l) and two (ICC 2'2) occasions (Shrout
and Fleiss 1 979). The ICCs were interpreted subjectively as follows: > 0.75 excellent,
0.40 - 0.75 moderate, and < 0.40 poor (Fleiss 1986). Standard error of measurement
(SEM) and 95% confidence intervals (CI) were calculated to describe measurement error
or variation with repeated testing, for both peak torque and distance hopped (Stratford
and Goldsmith 1997, Streiner and Norman 199 1).
A two-way analysis of variance (ANOVA) test (two movements by two muscle
actions) was used to test for statistically significant differences among the peak torques
(SPSS 1997). Following a significant F-ratio, a Newman-Keuls test was used to
compare selected means (Wirier et a1 1971).
The relationship between isokinetic peak torques and distance hopped was
determined using Pearson Product Moment Correlation Coefficients (SPSS 1997) and
interpreted using the guidelines proposed by Weber and Lamb (1970): An alpha level of
0.05 was used to designate statistical significmce throughout analysis.
CHAPTER 3
RESULTS
Only one of the subjects reported muscdar discomfort following the first test
occasion. However, the discomfort resolved within 48 hours of initial testing and did not
inhibit subsequent performance- Ail subjects completed the full test on two occasions,
with a minimum of 48 hours between test occasions, except for one subject for whom the
time between tests was 14 days, as a result of scheduling conflicts.
ALI of the subjects subjectively reported that the concentric-abduction strength test
was the most physically challenging and dficult to perform. The easiest test subjectively
reported by the subjects was the eccentric-adduction strength test. The subjects did not
subjectively prefer one hop test over the other.
The concentric-abduction strength test was the least reliable (ICCs 0.59 for one
test occasion and 0.74 for two test occasions), whereas reliability coefficients for the
other three strength tests were similar (ICCs 0.72 - 0.74 for one test occasion and 0.84 -
0.85 for two test occasions) (Table 2). Overall, none of the four reliability coefficients
were greater than 0.75 on occasion one, whereas three of the four had excellent reliability
(> 0.75) when data were averaged over two test occasions; although, the ICC for the
concentric-abduction strength test over two test occasions remained lower (ICC 2,2 =
0.74).
Reliability of the lateral and medial hops was excellent for both o w (ICCs 0.87
for medial and 0.9 1 for lateral) and two test occasions (ICCs 0.93 for medial and 0.95 for
lateral) (Table 3). For both strength and functional test data, ICCs increased, while SEMs
23
and 95% CIS decreased when scores were averaged over two occasions (Tables 2 and 3).
Tables 4 and 5 summarize peak torques and the results of the two way ANOVA
test (movement by muscle action). The main effects for movemeat and muscle action
were significant (p < 0.01). The adduction peak torques (E = 227) were significantly
greater than the abduction peak torques (n = 202) when the movement main effects were
analysed, and the eccentric peak torques (n = 247) were significantly greater than the
concentric peak torques (n = 180) when the muscle action main effects were adysed (p
< 0.01)-
Table 4 illustrates hop distances and Table 6 shows the results of the paired t-test
for the hop test (medial vs lateral directions). There was no significant difference in the
distance hopped between the medial and lateral hops @ > 0.05).
Table 7 shows that overall, aLI of the correlations between strength and functional
scores were poor-to-low and none of the correlations were statistically significant @ >
0.05)-
Movement Concentric Eccentric Concentric Eccentric Muscle Action Abduction Abduction Adduction Addaction
-
One test Occasion
SEM (Nm) 21 18 17 20
95% CI (Nm) 42 35 33 39
Two Test Occasion
ICC(2,2) 0-74 0.85 0.84 0.84
SEM (Nm) 14 13 11 14
95% CI (Nm) 28 25 22 28
ICC = Intraclass correlation coefficient. SEM = Standard error of measurement- 95 % CI = 95 % Confidence interval-
TABLE 2. Reliability of the isokinetic hip strength tests (n = 27 subjects).
Hop Direction .
Lateral M d a l
One Occasion
rcc (2,l)
SEM (cm) 6 7
95% CI (cm) 11 14
Two Occasions
ICC (2,2) 0-95 0.93
SEM (cm) 4 5
95% CI (cm) 9 10
ICC = Intraclass correlation coefficient. SEM = Standard error of measurement. 95% CI = 95% Confidence interval.
TABLE 3. Reliability of the hop tests (n = 27 subjects).
Test Occasion Test Occasion Two 1 2 Occasion
Mean
Mean SD Mean SD Mean SD
Strength tests (Nm)
Concentric-Abduction 169 33 174 30 172 28
Eccentric-Abduction 230 35 234 35 232 33
Concentric-Adduction 183 32 194 29 188 28
Eccentric-Adduction 259 38 263 40 261 36
Hop Tests (cm)
Lateral 156 19 159 21 157 20
Medial 158 20 163 19 160 19
TABLE 4. Mean and standard deviation (SD) of the strength and hop tests (n = 27).
- -
Variable Sum of df Mean F-ratio pvahe !squares square
Main Effects
Movement 25629 26 986 14 0-00 1
Muscle Action 19054 26 733 163 0.000
Interaction
Movement x 7913 26 304 4 0.07 1 Muscle Action
df= degrees of Worn
TABLE 5. Two way ANOVA for movements (abduction and adduction) by muscle actions (concentric and eccentric) @ < 0.05).
Variable Mean SD SEM t df s k (2
Lateral score vs -2.8 12.1 2.3 -1.2 26 0.24
Medial score
TABLE 6. Paired t-test comparison of distance hopped in the lateral and medial direction (values are for difference scores: cm)-
Muscle Action Movement Hop Direction
Lateral Medial
Concentric-Abduction
Eccentric-Abduction
Concentric-Adduction
Eccentric-Adduction
TABLE 7. Correlations (r) bebeem strength and hop scores (n = 27 subjects).
CHAPTER 4
DISCUSSION
The reliability coefficients for the present isokinetic strength tests were modest
(ICC 2,1< 0.75) for data collected on one occasion and generally exceUent (ICC 2 2 2
0.75) for data averaged over two occasions. The least reliable test, concentric-abduction,
approached but did not achieve excellent reliability when scores were averaged over two
test occasions (ICC = 0.74). The subjective reports that the concentric-abduction strength
test was the most difficult to perform may explain the lower reliability compared to the
other three strength tests. The remaining three tests approached excellent (KC 2,l = 0.72
to 0.74) reliability on one test occasion (Table 2). These values describe the per fomce
of the group of subjects. When expressed in tenns of variability of an individual's
performance, the reliability of the peak torques was lower and characterized by greater
measurement error. For example, measurement error (95% confidence intervals) for
concentric hip adduction was * 33 Nm, when determined on one occasion, and decreased
to * 22 Nm when determined over two test occasions (Table 2). As a result, using the
mean peak strength scores observed in the present study (Table 4) the peak torque of a
typical healthy male hockey player, as determined on one test occasion, could be expected
to lie between 1 SO and 2 16 Nm (1 83 * 33 Nm). If the data averaged over two test
occasions were used, the true peak torque score could be expected to lie within a
narrower range: 166 and 210 Nm (188 * 22 Nm). In other words, even if two test
sessions were performed and the subject improved his score as much as 20 Nm, this
change could still be attributed to measurement emor. As a result, even with a high
31
reliabsty coefficient, considerable change (> 12%) in the individual's score is required to
be confident that a true gain or loss in hip strength had occurred.
Ln view of the costs and clinical time associated with additional testing (two
occasions), techniques to maximize reliability on one test occasion need to be explored.
Study design changes that may improve the reIiability include increasing the number of
practice and test movement repetitions, having the subjects practice the test movements
at home before testing, or altering the test position (ie supine). The small range of
motion, size of the joint, uncommon isolated movement performed and unusual test
positioning may also have contniuted to the poor reliability of data measured on one
occasion.
The subjects in the present study were skilied athletes. Their ability to learn and
perform abnormal movement patterns, such as the isolated hip movements of isokinetic
abduction and adduction, may be much greater than a typical patient population. Lower
reliability coefficients may be observed when less skilied subjects are tested using similar
protocols. Further study is required to determine test-retest reliability for other
populations.
In the test-retest reliability study by Bumett et aI (1990), the ICCs reported for
abduction and adduction peak torques at the angular velocities of 30°/sec (ICC = 0.59 and
0.55) and 90°fsec (KC = 0.59 and 0.49) were generally lower than those in the present
study. However, it is diflicult to compare results due to the fact that the exact nature of
the K C computation reported by Bumett et a1 (1990) was not specified. In the present
study, only the concentric-abduction reliability coefficient determined on one test
32
occasion ( K C 2,1= 0.59) was as low as the Burnett et a1 (1990) values- The other three
hip strength tests used in the present study (eccentric-abduction, concentric-adduction and
eccentric-adduction) had greater reliability coefficients than the Burnett et a1 (1990) study
for both one (ICC 2,1= 0.72 to 0.74) and two ( K C 2,2 = 0.84 to 0.85) test occasions.
The present author attributes the greater reliability to alterations in the
methodology that were employed in the study. Although Bumett et a1 (1990) also secured
the pelvis and the non test lower extremity with straps in side lying, they suggested that it
was ineffective at preventing substitution of orher muscle groups which may have lead to
increased variability in the peak torque scores. In the present study, the examiner
provided force to the posterior aspect of the sacrum to minimize pelvic rotation and
further improve stabilization. Another variable that was not controlled by Burnett et a1
(1990) was the ROM of the test movements. The subjects were directed to move through
a certain ROM, but had no visual marker to determine when the end of ROM was
reached. The e x h e r s descn'bed 20% differences in hip abduction ROM over the two
test sessions. The Kin-Corn program used in the present study provided mechanical stops
at the end ROM that the examiner established prior to testing using goniometric
measurement. Therefore, the range of motion used by all of the subjects was standardized
and the subject knew when they had reached the end points of the required ROM.
Burnett et a1 (1990) also recommended that the 2-3 submaximal repetitions may not be
adequate for sufficient learning of the movement. The present study attempted to
improve the learning of the difEcult test movements by allowing seven practice
repetitions, four at submaximal intensity and 3 at maximum intensity. Finally, Burnett et
33
a1 (1990) also suggested that fatigue may have contn'buted to the poor reliability. They
used four continuous repetitions performed by the subjects, without rest. In the present
study, the strength tests were single repetition efforts followed by 30 second rest
intervals, in an effort to minimize fatigue
The reliability coefficients for isometric hip abduction peak torques (KC 2,1=
0.97 to 0.99) reported by Vaz et al(1993) were much higher than the one occasion
isokinetic concentric-abduction (KC 2,l = 0.59) and eccentric-abduction (ICC 2,l =
0.74) coefficients reported in the present study. The heterogeneity of the Vaz et al(1993)
sample (23 males and 20 females) may be one of the explanations for the higher values.
Since reliability coefficients are an expression of the variability between the subjects
relative to the total variability, they can be artificially inflated when a heterogeneous
sample is investigated. For example, using a group of subjects with a higher level of
variability, such as mixed male and female subjects, will result in improved reliability
coefficients. Other testing procedures, such as the belt resisted stabilization used by Vaz
et al(1993), may also have lead to improved consistency of test efforts. The
circumferential straps around the pelvis and the distal thighs allowed minimal movement
of the lower extremities, which may have minimized the substitution by other muscle
groups. Despite efforts to improve stabilization provided in the present study, the
strength of the athletes tested and the unique nature of the movements made it difficult to
eliminate substitution by other muscle groups during a maximum single repetition effort.
The excellent test-retest reliability found by Vaz et a1 (1 993) suggests that their isometric
method of testing may be a possible alternative to the isokinetic abduction tests used in
34
the present study- However, the extent to which isometric and isokhetic tests can be
used to predict the same functicd test is unclear.
The one-legged lateral hop test studied by Vandermeulen et a1 (1999) was
performed in an identical manner to the lateral hop for distance in the present study with
two exceptions. The hops in the Vandenneulen et a1 (1999) study were performed in bare
feet, while the subjects in the present study wore ;lmning shoes. The other difference was
the extremity used by the subjects to perform the hops. The present study tested the
subjects' hops on the dominant extremity (right side), while Vandenneulen et al(1999)
tested the subjects' hops on both the dominant and the non-dominant lower extremities.
In their study 46 normal males and females achieved right sided ICC 2'1 values of 0.83
and 0.86 for the lateral hop test, respectively. Among these subjects were 1 7 males that
recorded mean hop distances for both occasions of 1.3 1 * 0.17 m. The male subjects
studied by Vandenneulen et a1 (1997) also had * 0.08 m SEM and * 0.15 m 95% CI
values for the right leg. Higher ICC values (ICC 2,l = 0.9 1) and hop distances (1.57 * 0.20 m), as well as the lower SEM and 95% CIS (SEM = * 0.06 m and 95% CI = * 0.1 1
m) were reported in the present study. This may be partially attributable to the athletic
skill level of the hockey players. The ability of these subjects to learn a skilled
movement, such as the lateral hop for distance, may be much greater than the normal
healthy male subjects in the Vandermeulen et a1 (1999) study. The smaller sample size (n
= 17) and decreased confidence in performing the hop tests in bare feet may also account
for the differences.
Excellent reliability of the medial hop test was also observed in the present study
35
(ICC 2,1= 0.87). An advantage of investigating the medial hop in addition to the lateral
hop test is that destabilizing forces in athletic activities can occur in both directions. By
testing both medial and lateral directions, clinicians can observe a more representative
sample of an athlete's side to side movements-
The excellent reliability of the hop tests in the present study may make them quick
and cost-effective closed kinetic tests that only require one test occasion. Future research
studies should focus on determining the sensitivity and baseline values for the lateral and
medial hop tests in clinical populations.
In the present study the hockey players produced si@cantly larger adduction
torques than abductor torques. The eccentric peak torque scores were also significantly
higher than the concentric scores. Although previous studies (Donatelli et at 199 1,
Burnett et a1 1 990, Cahalan et aI 1 989, Tippett 1986, Poulmedis 1985) are in agreement
with the present findings, studies comparing isokinetic tests using concentric and
eccentric muscle actions in the hip were got avaiiabk
The velocity of the isokinetic testing in the present study was 60°/sec. Previous
studies have used a variety of testing velocities, with a tendency for the peak torques to
decrease as the velocity of the test movement increased (Burnett et a1 1990, Cahalan et al
1989, Ryser et al 1988, Tippett 1986, Poulmedis 1985). Donatelli et al(W9 1) dso tested
at the 60°/sec angular velocity. However, they used a different testing device (MERAC),
a different testing position (side lying facing away from the dynamometer head), their
subjects were healthy males and females, and the dynamometer lever arm had two contact
points. They reported that concentric peak torque for the 48 subjects (mean age = 26
36
years) to be 68 * 20 Nrn for abduction and 167 * 57 Nm for adduction. Both the
concentric-abduction (172 * 28 Nm) and concentric-adduction (I88 * 28 Nm) peak
torques in the present study were higher than those reported by Donatelli et aI (199 I).
Abduction peak torqye for female subjects was 147 * 33 Nm, while peak torque for males
was 207 * 73 Nm. The athletic sample in the present study may have produced higher
peak torques due to the increased lower extremity strength and stability acquired in the
skating motion. In agreement with the present study, the mean peak adductor torques
were statistically greater than the mean peak abductor torques (Donatelli et a1 199 1).
However, there was a much greater abduction to adduction mean peak torque difference
noted in the Donatelli et a1 (1991) study (99 Nm) compared to the present study (16 Nm).
This large difference may also be accounted for by characteristics of the subjects in the
present study. The importance of the hip abductor and adductor muscle groups in the
mechanics of skadng (ie. cross overs, change of direction, stopping, and acceleration
from a stopped position) for hockey players may have lead to a more balanced
development of these agonist and antagonist muscles.
Another study that measured the isokinetic hip abductor and adductor peak
torques in the side lying position on a Cybex II was performed by Cahalan et a1 (1 989).
Torques for the young males at 30°/sec averaged 103 * 26 and 121 t 26 Nm for
concentric-abduction and adduction, respectively. These were the highest torques
reported in their paper. In comparison, the mean peak torques for concentric-abduction
and adduction movements in the present study were 172 * 28 and 188 * 28 Nm,
respectively. The athletic skill level of the individuals, younger age and improvements in
37
test methodology may explain the difference between the studies seating and Matyas
1996).
Tippett (1986) measund concentric hip abduction and adduction torques in side
lying on 16 college baseball players using their stance and kick legs. Mean abduction
peak torques for the stance leg (109 * 36 Nm) and the kick leg (1 18 * 39 Nm) measured
at 3 OO/sec were lower than those for the present hockey players (1 72 28 Nm).
Similarly, the mean adduction peak torques measured on the stance leg (141 * 53 Nm)
and kick leg (145 t 44 Nm) were lower than those for the right leg of the hockey players
(1 88 * 28 Nm). The age level (mean age = 20 years) and athletic skill level of the
baseball players were similar to the present study, however the smaller number of
subjects tested and the methodology descni may help to explain the lower values.
Tippett (1986) ailowed only two submaximal warm-up repetitions for each motion. This
may not have given the subjects adequate time to practice and leam the abnormal hip
abduction and adduction movements prior to testing. Furthermore, the short rest
duration, 30 second rest between each test velocity, combined with the 5 continuous
(Cybex IC) test repetitions may have contributed to subject fatigue and lower peak torque
values.
Isokinetic (30°/sec) concentric-abductor (1 19 * 24 Nm) and adductor (1 60 1 7
Nm) strength in 18 elite Greek soccer players (Poulmedis 1985) was also lower than the
values reported in the present study. The age of the soccer players (mean age = 28 years)
compared to the younger hockey players (mean age = 20 years) and the small sample size
(n = 18) may account for the lower values observed.
38
In the present study, the correlations between hop dis*ince~ and the isokinetic hip
torques were slight-to-poor and not statistically significant This indicates that the
isokinetic evaluation of hip strength during isolated hip abduction and adduction
movements is a poor predictor hip pafomutnce. In agreement with this finding, several
authors have previously stated that a subject's dynamic functional ability cannot be
adequately ascertained through isokinetic testing (Greenberger and Paterno 1995, Lephart
et al1993). Many other factors, independent of strength, can contribute to the hctionaI
performance of an athlete, such as balance, co-ordination, power, muscle recruitment,
flexibility, endurance, skill level, environment and confidence in performance.
Lack of test-function specificity may have contributed to the poor correlations
observed. The isokinetic and hop tests used in the present study may not have been
representative enough of skills used by hockey players in game or practice situations.
Although the side Lying isokinetic hip strength tests involved movements that were
specific and isolated to the hip joint, they appear not be good predictors of the strength
requirements of athletes when performing specific hockey skills. The test-hction
specificity of the medial and lateral hops for distance is also questionable. The extent to
which hops can predict skating or even more high level hockey hct ions appears to be
Limited. Future studies that investigate specific on-ice activities, such as skating speed
over a selected distance, may be required to better assess a hockey players' readiness to
return to sport or higher hctional activity.
Vaz et a1 (199 1) found correlations between isometric hip strength and functional
measures that ranged h m slight-to-moderate (r = 0.10 to 0.5 1). The relationship between
39
hip abductor torques and the 6 minute walk test was significant (r = 0.48 to 0.51, p <
0.01). These strength-function correlations were much higher than those in the present
study. The difference in findings may be due to the skill components involved, as well as
the sample studied Whereas, the 6 minute walk test involves a basic functional task that
is performed by all the subjects on a daily basis, the hop tests in the medial and lateral
directions are not activities of daily living. The medial and lateral hop tests involve
components that utilize skills such as balance, co-ordination, and power. The relationship
between an isolated strength test and a fimctional test may be higher in a sample of
subjects who do not have the skill level of trained athletes. Similar relationships may be
the case when investigating pathological groups that are not hctioning at a normal level.
Clinical Relevance
In order to maximize reliability and reduce the measurement error encountered
during isokinetic testing for hip abduction and adduction strength, clinicians should test
subjects on two occasions. However, only one testing session is required for hop tests.
Clinicians must be careful not to assume a strong relationship between joint specific
isokinetic tests and fhction. Isokinetic tests done are not sufficient to determine if an
athlete is ready to return to sports, such as hockey.
Conclusions
Test-retest reliability for isokinetic hip strength testing was moderately high
reliable, but the 95% CIS were wide. At least two test occasions were r e w e d to achieve
acceptable test-retest reliability when using the current test methodology. Test-retest
reliability for the lateral and medial hop tests was excellent and characterized by smaller
95% CIS. The relationship between strength and function was slight-to-poor, md
suggests that fimction cannot be predicted fiom joint specific strength testing. Future
studies need to consider ways to increase reliability in isokinetic hip strength testing and
examine other populations using the functional and isokinetic tests.
APPENDICES:
Appendix A: Ethics Approvd, Letter of Information and I n f b d Consent
Appendix B: Verbal Instructions
NOTE TO USERS - - . . - -
Page(s) not included in the original manuscript - '-- are unavailable from the author or university. The-
manuscript was microfilmed as received.
This reproduction is the best copy available.
UMI
Relationship Between Strength of the Hip MusculPture and Hop Tests
The study seeks to determine the strength of the muscles used to move your leg. It will also determine if hip movements can be measured reliably and how they are related to a sideways hop test. This hop test may be used in preseason testing or in making treatment and return to play/work decisions.
If you agree to participate, you wil l be tested on two occasions, about one week apart, in the Muscular Assessment Laboratory, School of Physical Therapy, University of Western Ontario (Room 1408). Each test occasion will take about 60 minutes. Muscle strength of your dominant leg will be tested while positioned in side lying and using exercises which require you to move your thigh away and towards your body while you push against a resistance pad. You will also be asked to hop sideways h m one leg and landing on that leg without losing balance, three times.
Before each test of muscle strength, you will have the opportunity to practice the test movements and ask any questions you may have. The strength test involves 3 maximal effort repetitions for each leg of four different movements producing a total of 12 maximal efforts over about a 45 minute period. Frequent rest periods will be provided.
Due to the fact that you will be performing exercises with maximum effort, some muscle soreness may develop. Any such discomfort is expected to be minor and similar to that which you have experienced after completing other exercises. Should you experience any leg discomfoa while testing, testing will be stopped immediately.
Please feel fkee to ask any questions that you may have concerning the study. Participation in the study is voluntary- You may refuse to participate, or withdraw &om the study at any time with no effect on your academic standing.
Your identity and results of the study will remain confidential to the primary investigators involved with the study.
Please call Jason Kea (EXome: 473-0585 or work: 661-2 1 1 1 ext 883 1) for fiuther information about the study.
Jason Kea Bsc (P.T.) Clinical Fellow in Sports Physiotherapy Fowler-Kennedy Sports Medicine Clinic
John Kramer Director of the School of Physiotherapy Elborn College, U.W.O.
44
Relationship Between Strength of the Hip Musculature and Bop Tests
I have read the accompmying letter of information, have had the nature of the
study explained to me and I agree to participate. Any questions have been answered to -
my satisfaction.
Signed
Dated
Lateral Hop Test (Zatemf Diredon Fim)
The test that you will do first is called the lateral hop test. W e are interested in testing how consistently you can hop to your maximum distance. You will stand on your [rightheft] leg with the inside of your fmt Lined up with the tape. Your instructions are to hop as far as you can to your [right/left] side, hopping fbm one leg and landing on the same leg. You must maintain your balaoce on the landing leg for 5 seconds. It wil l not affect the testing ifyou lose your balance or put your other foot down. We will simply continue attempting test hops until 3 tests are completed.
Prior to the test jumps you will be allowed a number of progressively longer practice jumps. The testing will not be started until you are comfortable that you are performing consistently maximum hops.
Let's try some practice jumps first. To start try a few short jumps.
Now let's try some jumps where you jump as far as you can consistently. Remember, do not feel bad if you are unable to maintain your balance during testing. Do you feel comfortable with the test movement ?
I will give you a 30 second break and then we will begin the test hops. With all three of the tea hops you are asked to consistently hop as far as you can. Try to hop as far as you can.
We will repeat the same hop as far as you can.
The next test is exactly the same as the first test, except you will stand on your [rightfleft] leg with the outside of your foot lined up with the tape and you wiU jump as far as you can to the neft/'ght]. Other than this change we wil l perfom the test the same as the first test. Again the importance is jumping as f a as you can consistently.
Lateral Hop T& (2HediaO Dire~nin First)
The test that you will do first is called the lateral hop test We are interested in testing how consistently you can hop to your maximum distance. You will stand on your [rightAeft] leg with the outside of your foot lined up with the tape* Your instructions are to hop as far as you can to your PeWright] side, hopping fiom one leg and landing on the same leg. You must maintain your balance on the landing leg for 5 seconds. It will not affect the testing if you lose your balance or put your other foot down. We will simply continue attempting test hops until 3 tests are completed
Prior to the test jumps you will be allowed a number of progressively lmger practice jumps. The testing wilI not be started until you are comfortab1e that you are performing consistently maximum hops.
Let's try some practice jumps first. To start try a few short jumps.
Now let's try some jumps where you jump as fsr as you can consistently. Remember, do not feel bad if you are unable to maintain your balance during testing. Do you feel comfortable with the test movement ?
I will give you a 30 second break and then we will begin the test hops. With a l l three of the test hops you are asked to consistently hop as far as you can. Try to hop as far as you can.
We wil l repeat the same hop as far as you can.
The next test is exactly the same as the first test, except you wi l l stand on your [rightneft] leg with the inside of your fmt lined up with the tape and you will jump as far as you can to the [rightfieft]. Other than this change we will perform the test the same as the k t test. Again the importance is jumping as far as you can consistently.
The machine that we will perform the hip strength tests on is called the Kinetic- Communicator- This is an isokinetic strength testing device. This means that the machine will measure the amount of strength your muscles produce as you move your leg. The device will maintain a slow co-t speed as you push or pull. We are interested in how consistently you can perform your maximum effort, especially on two separate days. The key to the tests is to push or pull in the test direction as hard as you can and to maintain this maximum push or pull throughout the test movement- I will be using my hands to keep your peIvis secure fiom behind
Second Day - Intmduction
Remember, we are interested in how consistently you can perform your maximum effort, especially on two separate days. The key to the tests is to push or pull in the test direction as hard as you can and to maintain this maximum push or pull throughout the test movement.
This strength test measures your ability to push the testing pad towards the ceiling. The machine wilI monitor how consistently you can perform your maximum push. You must continue pushing up until the machine stops the movement after about 40 degrees of travel. The machine will not record until you have started pushing up into the pad-
We will start with 4-6 practice movements to familiarize you Rith the test movement,
Try the fim movement with minimal effort when you are ready.
Notice how the movement does not start until you have initiated it Remember to keep pushing all the way through the movement. Let's try another with 50% effort when you are ready.
~t Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a maximum push.
If yes - We will try after a 30 second break I If no *
When you are ready push up as hard as you can and keep pushing all the way through the movement [Pretest I]. We will try another practice after a 30 second break.
When you are ready push up as hard as you can all the way through the movement [Pretest 2/31. Do you feel confident enough to attempt the test movement?
If yes - Go to ** / IfNo - repeat Pretest 3
**We are going to perform 3 test movements exactly the same as the last practice movements with 30 second breaks.
This strength test measures your ability to pull the testing pad down towards the floor. The machine will monitor how consistently you can perform your maximum pull. You must continue pulling down until the machine stops the movement after about 40 degrees of travel. The machine will not record untii you have started to pull your leg down and it will not move under the weight of your suspended limb.
W e will start with 4-6 practice movements to familiarize you with the test movement-
Try the Grst movement with minimal effort when you are ready.
Notice how the movement does not start until you have initiated i t Remember to keep pulling all the way through the movement Let's try another with 50% effort when you are ready.
* Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a maximum pull.
If yes - We will try after a 30 second break / If w *
When you are ready pull down as hard as you can and keep pulling all the way through the movement [Pretest I ] . We will try another practice a& a 30 second break.
When you are ready pull down as hard as you can all the way through the movement [Pretest 2/31. Do you feel confident enough to attempt the test movement?
If yes - Go to ** / If No - repeat Pretest 3
**We are going to perform 3 test movements exactly the same as the last practice movements with 30 second breaks.
This strength test measures you. ability to prevent the testing pad h m pulling your leg up towards the ceiling. The machine will monitor how consistently you can perform your maximum pull. You wil l be unable to stop the pad from pulling your leg up, however, your maximum pull is still required- You must continue pulling down until the machine stops the movement after about 40 degrees of travel. The machine wi l l not record until you have started to pull your leg down.
We will start with 4-6 practice movements to familiarize you with the test movement.
Try the first movement with minimal effort when you are ready. Notice how the movement does not start until you have initiated it. Remember to
keep pulling all the way through the movement. Let's try another with 50% effort when you are ready.
* Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a maximum pull.
If yes - We will try after a 30 second break f If no *
When you are ready pull down as hard as you can and keep pulling all the way through the movement [Pretest I]. We will try another practice after a 30 second break-
When you are ready pull down as hard as you can all the way through the movement [Prerest 2/31. Do you feel confident enough to attempt the test movement?
If yes - Go to ** I If No - repeat Pretest 3
**We are going to perform 3 test movements exactly the same as the last practice movements with 30 second breaks-
Hip ABductiion - Eccentric flnifibf test?
This strength test measures your ability to prevent the testing pad fkom pushing your leg down towards the floor. The machine will monitor how consistently you can perform your maximum push. You will be unable to stop the pad fiom pushing your leg down, however, your maximum push is still required- You must continue pushing up until the machine stops the movnnent after about 40 degrees of travel. The machine will not record until you have started to push your leg up.
We will start with 4-6 practice movements to familiarize you with the test movement.
Try the first movement with minimal effort when you are ready. Notice how the movement does not start until you have initiated it. Remember to
keep pushing all the way through the movement. Let's try another with 50% effort when you are ready,
~t Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a rnaximuum push.
Eyes - We will try after a 30 second break I If no *
When you are ready push down as hard as you can and keep pushing all the way through the movement [Pretest I]. We will try another practice after a 30 second break
When you are ready push down as hard as you can all the way through the movement [Pretest 2/31. Do you feel confident enough to attempt the test movement?
If yes - Go to * * / If No - repeat Pretest 3
**We are going to perfom 3 test movements exactly the same as the last practice movements with 30 second breaks.
This strength test measures your ability to push the testing pad towards the ceiling- The machine will monitor how consistently you can perform your maximum push. You must continue pushing up until the machine stops the movement after about 40 degrees of travel.
We will start with 4 6 practice movements to fdarize you with the test movement-
Try the k t movement with minimal effort when you are ready.
Remember to keep pushing all the way through the movement. Let's try another with 50% effort when you are ready.
* Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a maximum push.
If yes - We will try after a 30 second break / If no *
When you are ready push up as hard as you can and keep pushing all the way through the movement [Pretest I ] . W e will try another practice after a 30 second break.
When you are ready push up as hard as you can all the way through the movement [Pretest 2\31. Do you feel confident enough to attempt the test movement?
If yes - Go to ** / If No - repeat Pretest 3
**We are going to perform 3 test movements exactly the same as the last practice movements with 30 second breaks.
This strength test measures your ability to pull the testing pad down towards the floor. The machine wil l monitor how consistently you can perform your maximum pull. You must continue pulling down until the machine stops the movement after about 40 degrees oftravel. The machine wiU not record until you have started to pull your leg down and it will not move under the weight of your suspended Limb.
We will start with 4-6 practice movements to familiarize you with the test movement.
Try the first movement with minimal effort when you are ready-
Remember to keep pulling al l the way through the movement. Let's try another with 50% effort when you are ready.
* Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a maximum pull.
If yes - We will try after a 30 second break / If no *
When you are ready pull down as bard as you can and keep pulling all the way through the movement [Pretest I ] . We will try another practice after a 30 second break.
When you are ready pull down as hard as you can all the way through the movement [Pretest 2/31. Do you feel confident enough to attempt the test movement?
If yes - Go to ** I If No - repeat Preresst 3
**We are going to perform 3 test movements exactly the same as the last practice movements with 30 second breaks-
This strength test measures your ability to prevent the testing pad from pulling your leg up towards the ceiling. The machine will monitor how consistently you can perform your maximum pull. You will be unable to stop the pad @om pulling your leg up, however, your maximum pull is s t i l l required- You must continue pulling down until the machine stops the movement after about 40 degrees of travel.
We will start with 4-6 practice movements to familiarize you with the test movement,
Try the first movement with minimal effart when you are ready.
Remember to keep pulling all the way through the movement. Let's try another with 50% effort when you are ready.
* Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a maximum pull.
If yes - We will try after a 30 second break / If no *
When you are ready pull down as hard as you can and keep pulling all the way through the movement [Pretest I]. We will try another practice after a 30 second break.
When you are ready pull down as hard as you can all the way through the movement [Pretest 22/31. Do you fed confident enough to attempt the test movement?
If yes - Go to ** / IfNo - repeat Pretest 3
**We are going to perform 3 test movements exactly the same as the last practice movements with 30 second breaks.
This strength test measures your ability to prevent the testing pad from pushing your leg down towards the floor. The machine will monitor how consistently you can perform your maximum push. You will be unable to stop the pad h m pushing your leg down, however, your maximum push is stil l required. You must continue pushing up until the machine stops the movement after about 40 degrees of travel.
We will start with 4-6 practice movements to familiarize you with the test movement-
Try the first movement with minimal effort when you are ready-
Remember to keep pushing all the way through the movement. Let's try another with 50% effort when you are ready.
r~ Now try the same with about 75% effort when you are ready.
Do you feel comfortable enough with the movement to attempt a maximum push.
If yes - We will try after a 30 second break I If no *
When you are ready push down as hard as you can and keep pushing all the way through the movement [Pretest 11. We will try another practice after a 30 second break.
When you are ready push down as hard as you can all the way through the movement [Pretest 2/31, Do you feel confident enough to attempt the test movement?
If yes - Go to ** / If No - repeat Pretest 3
** W e are going to perform 3 test movements exactly the same as the last practice movements with 30 second breaks.
56
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