The effectiveness of manual stretching in thetreatment of plantar heel pain: a systematic reviewDavid Sweeting1,2*, Ben Parish1,2, Lee Hooper1 and Rachel Chester1,3
Abstract
Background: Plantar heel pain is a commonly occurring foot complaint. Stretching is frequently utilised as atreatment, yet a systematic review focusing only on its effectiveness has not been published. This review aimed toassess the effectiveness of stretching on pain and function in people with plantar heel pain.
Methods: Medline, EMBASE, CINAHL, AMED, and The Cochrane Library were searched from inception to July 2010.Studies fulfilling the inclusion criteria were independently assessed, and their quality evaluated using the modifiedPEDro scale.
Results: Six studies including 365 symptomatic participants were included. Two compared stretching with acontrol, one study compared stretching to an alternative intervention, one study compared stretching to bothalternative and control interventions, and two compared different stretching techniques and durations. Qualityrating on the modified Pedro scale varied from two to eight out of a maximum of ten points. The methodologiesand interventions varied significantly between studies, making meta-analysis inappropriate. Most participantsimproved over the course of the studies, but when stretching was compared to alternative or controlinterventions, the changes only reached statistical significance in one study that used a combination of calf musclestretches and plantar fascia stretches in their stretching programme. Another study comparing different stretchingtechniques, showed a statistically significant reduction in some aspects of pain in favour of plantar fascia stretchingover calf stretches in the short term.
Conclusions: There were too few studies to assess whether stretching is effective compared to control or otherinterventions, for either pain or function. However, there is some evidence that plantar fascia stretching may bemore effective than Achilles tendon stretching alone in the short-term. Appropriately powered randomisedcontrolled trials, utilizing validated outcome measures, blinded assessors and long-term follow up are needed toassess the efficacy of stretching.
BackgroundPlantar heel pain is one of the most commonly occurringfoot complaints treated by healthcare professionals [1].Reliable population based incidence data is lacking inmany countries [2]. Within the American population, itsincidence has been estimated to be 10% at some pointwithin a lifetime [3] and has been suggested to account forover one million medical visits per annum [4]. It can havea detrimental effect on physical activity, social capacity,mood and vigor [5,6]. Published data estimating treatment
and financial costs to the individual and workplace arelacking.Plantar heel pain is thought to be most commonly
associated with the plantar fascia - when the term plantarfasciitis is commonly adopted, but differential diagnosismay include: calcaneal fracture, heel pad atrophy andpain of neural origin [7]. The plantar fascia is a band offibrous tissue that originates from the medial tubercle ofthe calcaneus and stretches to the proximal phalanx ofeach toe [8]. The condition of Plantar Fasciitis is thoughtto arise from overuse or repetitive micro trauma of thetissue [9]. As the aetiology of plantar fasciitis is unclear,diagnosis is usually based on clinical signs including:plantar heel pain when weight-bearing after a period onnon-weight-bearing, pain that eases with initial activity,
* Correspondence: [email protected] of Medicine and Health Sciences, University of East Anglia, Norwich,Norfolk, NR4 7TJ, UKFull list of author information is available at the end of the article
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but then increases with further use as the day progresses,and pain on palpation [1,10,11].Treatments for plantar heel pain are varied and
research findings supporting their use are sometimesconflicting. Stretching is frequently utilised as a conserva-tive treatment for plantar heel pain [1,12]. Systematicreviews investigating the efficacy of conservative treat-ments for plantar fascia have been published [4,11,13].However none of the reviews have focused specificallyupon stretching. In addition, research investigating theeffectiveness of stretching has been published since thesearches were performed for these reviews. Indeed theCochrane review [13] evaluating interventions for plantarheel pain has recently been withdrawn (2010) because itis out of date. There is a need for a rigorous systematicreview specifically focusing on the effectiveness of man-ual stretching as a treatment for plantar heel pain. Theobjective of this review was to evaluate the effectivenessof stretching compared with no treatment or other con-servative treatments on pain and function for people withplantar heel pain. A secondary objective was to identifywhat type of stretching is most effective in reducing painand increasing function.
MethodsSearch strategyThe literature search included the following bibliographicelectronic databases: Medline, EMBASE, AMED (all viaOvid), The Cochrane Library and CINAHL (via EBSCO)from inception to July 2010. The search terms used andcombined for Medline are detailed in Table 1. Additionalsearches were undertaken via “clinicaltrials.gov” search-ing for unpublished trials and via the PhysiotherapyForum “interactive csp” (http://www.interactivecsp.org.uk). Neither of these sources provided any further papersto include in the review. Five hundred and twenty sevenpotential titles and abstracts were identified from thesesources.
Study selectionIncluded studies fulfilled the following criteria: prospec-tive controlled trial, investigating adults (over 18 years ofage) with plantar heel pain, where stretching (either bythe patient themselves, or applied by a therapist but notvia a splint or brace) was compared to an alternativeintervention or no treatment, published in English, andreporting at least one validated outcome measure, (ormeasurement by numerical rating scale) relating to painor function. Studies investigating the effectiveness ofstretching applied by splints or bracing, were excludedon the basis that a stretch applied by apparatus over aperiod of hours was considered a significantly differenttreatment to stretches applied by the patient themselvesor a therapist for a matter of seconds. For inclusion
within this review participants needed to either have anexplicit diagnosis of plantar heel pain/fasciitis, or fulfill atleast two of the following criteria: pain localised to theplantar tissues, localised pain on palpation of the plantartissues, plantar pain on taking first steps after a period ofnon-weight-bearing that initially eased but then increasedwith further use. Both unilateral and bilateral diagnosisor clinical presentations were included. The titles andabstracts resulting from the electronic searches wereroughly de-duplicated by loading them onto referencemanagement software (Endnote X4), and then assessedindependently in duplicate by two reviewers.
Data extraction and study quality assessmentTwo reviewers independently extracted data from eachincluded study using a data extraction form developed forthis review. The completed forms were compared foraccuracy and interpretation; where there was disagreementor any ambiguity, both reviewers met to reach agreement.Such disagreements were few in number, but no specificrecord of them was maintained. If disagreement arose anda consensus could not be reached, the plan was that anydisagreement would be settled by further discussion withthe third or fourth investigator who would adjudicate ifnecessary. No disagreements arose which could not beresolved by discussion and always involved clarity of
Table 1 Search strategy used in Medline (Ovid) and runto July 2010
Database: Ovid MEDLINE(R) In-Process & Other Non-IndexedCitations and Ovid MEDLINE(R) <1950 to Present > SearchStrategy:
1. exp Fasciitis, Plantar/2. (plantar* adj5 (heel* or fasciit*)).mp.3. pain*.mp.4. 2 and 35. ((plantar* adj5 fasciit*) or (spur* syndrome* adj5 (heel* orcalcaneal*))).mp.6. (pain* adj3 heel*).mp.7. 1 or 4 or 58. (stretch* or conservative*).mp.9. exp exercise movement techniques/or exp exercise therapy/or expmusculoskeletal manipulations/10. 18 or 911. 6 and 1012. 7 or 1113. 1randomized controlled trial.pt14. controlled clinical trial.pt15. randomized.ab16. placebo.ab17. drug therapy.fs18. 1randomly.ab19. trial.ab20. groups.ab21. randomised.ab22. 18 or 15 or 19 or 21 or 14 or 20 or 13 or 16 or 1723. (animals not (human and animals)).sh24. 22 not 2325. 12 and 24
This search was used as the basis of the searches developed for the otherdatabases
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information, sometimes involving the whole team ofinvestigators.Methodological quality was evaluated via the PEDro
(Physiotherapy Evidence-Based Database) scale, (http://www.pedro.org.au). The exact criteria assessed are foundin Table 2. Elements were only scored as “yes” where qual-ity clearly met the specified criteria. Where criteria werenot met or were unclear, a “no” was scored. Again, thiswas independently undertaken by two of the reviewers. Ifdisagreement arose and a consensus could not be reached,the plan was that any disagreement would be settled bythe third investigator or adjudicator. No disagreementsarose which could not be resolved by discussion andalways involved clarity of information.
AnalysisStudy data were tabulated. Results were assessed to seeto whether grouping and meta-analysis would be appro-priate. The corresponding author of the three studieswhich did not provide sufficient data in the text (meandifference between pre and post treatment and standarddeviation for each group) [14,17,18] were contacted byemail requesting further details. One reply was received[14] but standard deviations were not available.
ResultsAssessment of the 527 titles and abstracts resulting fromthe searches resulted in exclusion of 495. See PRISMA(Preferred Reporting Items for Systematic Reviews andMeta-Analyses) flow diagram in Figure 1. The remaining32 were obtained and the full text assessed for inclusion.Twenty-six papers were rejected, as they did not fit the
required criteria. A total of six articles were thereforeincluded in this systematic review [14,15,17-20].
Study characteristicsFive of the six studies utilised a randomised parallel-groupdesign, one of which is described as a pilot study [20] andone study [18] used a “single-blind crossover design”. Asummary of study and participant characteristics includingtheir clinical signs and symptoms is provided in Table 3.Study quality assessment is summarised in Table 2, andfollow up, compliance and details of harmful effects inTable 4. A summary of stretching interventions isprovided in Table 5.A total of 365 symptomatic participants, 140 males
and 225 females, were included in this review (of whom269 were allocated to stretching). All studies stated theirsubject’s age, which ranged from twenty-three [15] tosixty-six years [18], mean age in any one interventiongroup ranged from 34 years [17] to 51 [19]. Four studiesrecruited participants using methods of conveniencesuch as during scheduled visits to an orthopaedic clinic[14], fliers and advertisements [17,19]. Two studies didnot provide details of recruitment [15,20]. The studiesvaried in duration of follow up from one week [17] tofour months [14].The interventions and comparisons are summarised in
Table 5. A variety of stretching techniques were appliedin the six studies, with five including tendo Achilles/calfmuscle stretches [14,15,17,19,20]. Three papers alsoincluded a stretch applied to the plantar fascia, by thepatient [15,20] or the therapist [17]. Wynne et al [18]investigated the effectiveness of stretches applied by a
Table 2 Results for the modified PEDro rating scale of methodological quality (Item one has been removed from thetotal score)
2) Subjects were randomly allocated to groups (in a crossover study, subjects wererandomly allocated an order in which treatments were received)
YES YES YES YES YES NO
3) Allocation was concealed YES NO NO YES NO NO
4) The groups were similar at baseline regarding the most important prognosticindicators
NO YES YES YES YES NO
5) There was blinding of all subjects NO NO NO YES NO NO
6) There was blinding of all therapists who administered the therapy NO NO NO NO NO NO
7) There was blinding of all assessors who measured at least one key outcome NO NO NO NO YES NO
9) All subjects for whom outcome measures were available received the treatmentor control condition as allocated or, where this was not the case, data for at leastone key outcome was analysed by “intention to treat”
NO NO NO YES NO NO
10) The results of between-group statistical comparisons are reported for at leastone key outcome
YES YES YES YES YES YES
11) The study provides both point measures and measures of variability for at leastone key outcome
YES YES YES YES YES NO
TOTAL SCORE OUT OF 10 (question 1, not included in total score) 4 5 4 8 5 2
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therapist to the foot and calf. The precise selection ofstretch used by Wynne et al [18], varied from one parti-cipant to another based upon the degree of relief it pro-vided to points of local tenderness.The duration and frequency of stretches varied widely
between the studies. Stretching programmes were com-pared to a range of alternatives including: differentstretching techniques, [14,15], calcaneal taping [17], bra-cing [20], sham ultrasound [19], sham anti-inflammatory
tablets [18] and no treatment [17]. The therapist appliedstretches directly to the participants in two studies[17,18], while other studies participants were asked tocarry out stretches themselves as part of a home exer-cise programme [14,15,19,20].Five of the studies measured functional ability using a
variety of validated measurement tools; these included thepatient specific functional scale [17,21], American Acad-emy of Orthopaedic Surgeon’s Lower Limb Core Module,
Figure 1 PRISMA flow diagram
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Foot and Ankle Module Questionnaire [14,20,22] the FootHealth Status Questionnaire [19,23] and the Foot FunctionIndex [15,24]. Five studies measure pain as an outcome;two [17,19] using a visual analogue scale, demonstrated tobe both valid and reliable [25]. Two studies used the painsubscale of their functional score [15,20], and one [14] didnot clearly state how pain was measured; they appear tohave extracted questions related to pain from the Foot andAnkle Module Questionnaire. Rather than divide the out-come into pain or function, Wynne et al [18] stated“symptom severity” as a combined score relative to pain,soreness, stiffness and mobility.
Study qualityThe results of the PEDro rating are shown in Table 2.The quality of the studies as determined via the PEDrorating scale ranged from two to eight out of a possible
score of ten. Four of the six studies did not documentthat an intention to treat analysis was used, with threeof these studies [14,15,20], not including at least onekey outcome measure from at least 85% of participantsallocated to each group.A total of 296 participants were included in the final
analyses, with attrition rates from 0% at 2 weeks [19] to24% at 12 weeks [20]. Larger losses to follow up werenoted in studies of longer duration [14,20]. One studyreported that there was no loss to follow up [19]. Allthe other five studies provided numbers for participantslost to follow up, but only two provided reasons [14,18].Details of numbers lost to follow up are provided inTable 4.Compliance with treatment regimes was only reported
in detail by Porter et al [14] whose sustained stretchinggroup completed 74.5% of their stretches compared to
Table 3 Summary of study characteristics
DiGiovani et al[15]
Hyland et al[17]
Porter et al[14]
Radford et al[19]
Sharma andLoudon
[20]
Wynne et al[18]
Recruitment Patients with plantarfasciitis not
responsive toprevious conservative
treatment
GeneralPractitioner’ssurgeries and
local gyms
Orthopaedicclinic
Local community(newspaper
adverts)
Local communityand university
Localcommunity &
physicianreferrals
Clinical signs and symptoms Maximal pain onpalpation of plantar
fascia origin.Diagnosis of plantar
fasciitis by a Physician
Pain > 3/10 oninitial
weightbearing.Pain localised atthe plantar heel
Pain localised atthe plantar heel.Pain at worst on
initial weight-bearing
Pain localised atthe plantar heel.Pain at worst on
initial weight-bearing
Diagnosis ofplantar fasciitisby a Physician
Diagnosis ofplantar fasciitis
Sample size for each group A: plantar fasciastretch (non
weightbearing) n =51
B: tendo Achillesstretch
(weightbearing) n =50
A: Stretch (nonweightbearing),
n = 10B: Calcaneal
taping n = 11C: No treatment(control) n = 10,
D: Sham tape(Control) n = 10
A: tendo Achillessustained.
stretch(weightbearing)
n = 54B: tendo Achilles
intermittentstretch
(weightbearing)n = 40
A: Calf musclestretch and sham
ultrasound(weightbearing) n
= 46B: Sham
ultrasound(Control) n = 46
A: Stretchingexercises (plantarfascia and tendoAchilles) n = 8
B: staticprogressive
stretch anklebrace n = 9
A: Counterstrain(non
weightbearing)n = 10
B: Placebo non-steroidal anti-inflammatory
(Control) n = 10
Mean age (SD, range) in years A: 44.6 (23-60)B 47.1 (31-60)
A 34.1(5.9),B 45.5 (12.0), C
40.4 (9.4), D37.6 (10.1)
A 45.4 (11.1)B 45.9 (12.1)
A 50.7 (11.8)B 50.1 (11.0)
A 40.3 (7.0)B 44.2 (11.3)
Mean notdocumented
(20-66)
Symptom duration. Numberof subjects and meanduration or range andpercentage if unavailable(months)
Abbreviations: SD = standard deviation. Letters A, B, etc refer to group allocation.
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81.2% in the intermittent group (p = 0.218). Radford etal [19] and DiGiovanni et al [15] both asked their parti-cipants to keep an exercise log but did not report theresults. DiGiovanni et al [15] questioned their partici-pants, and found that one participant in the plantar fas-cia stretching group and four in the Achilles tendon
stretching group had stopped stretching at 8 weeks; rea-sons were not provided.
Effectiveness of stretchingHeterogeneity between stretch techniques and compari-son groups made meta-analysis inappropriate. The
Table 4 Follow up, compliance and details of harmful effects
Overall 5% (n =1) Crossover trialtherefore drop-out not specific
to a singlegroup
Reasons fordropping-out
Not stated Not stated Requested injection orsurgery. Unwilling to travel.Other medical disorders. (no
break-down provided)
Not applicable Not known. Subject failed torecord data fully,results therefore
discarded.
Reports ofharmfuleffects
Not stated No adverseeffects fromtaping. Nostatement
aboutstretching
Not stated Stretching group:Increased heel pain (n= 4), Calf pain (n = 4).New lower–limb pain(n = 2). Control group:
nil
Nonereported.
Not stated
Table 5 Summary of stretching interventions
DiGiovanni et al[15]
Hyland et al[17]
Porter et al[14]
Radfordet al[19]
Sharma andLoudon (2010)
Wynne et al[18]
StretchingGroups
A B A B
Type of Stretch Plantar Fascia.Thumb palpationof Plantar Fascia
tension.
TendoAchilles
Gastrocnemius/Soleus Plantar
Fascia bytherapist
TendoAchilles
for 3minutes
TendoAchillesfor 20
seconds
TendoAchilleson step
Plantar Fasciastretches and
massage. TendoAchilles stretch
“Counter-strain” inposition of 70-80%symptom relief of
tender points.
Applied by Patient Patient Therapist Patient Patient Patient Patient Therapist
Duration ofStretch
10 seconds 10seconds
30 seconds 3minutes
20seconds
NotDescribed
30 seconds 90 seconds
Frequency ofStretch
10 reps,3 × daily
10 reps,3 × daily
3 reps on day1,
and 3 on day4
1 rep,3 × daily
5 reps,2 × daily
5minutes
daily
3 reps3× daily
Not described
Weightbearing/Nonweightbearing
Non weightbearing
Weightbearing
Non weightbearing
Weightbearing
Weightbearing
Weightbearing
Non weight bearingand weight bearing
Non weight bearing
Knee flexed orextended
Flexed Extended Flexed andExtended
Extended Extended Notdescribed
Flexed andExtended
Not described
Into/Out ofPain
“To feel stretch” “To feelstretch”
Not described Notdescribed
Notdescribed
Notdescribed
Not described Not described
Supervised? No No Not applicable No No No No Not applicable
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studies were grouped according to the comparisongroup for stretching: stretching versus no treatment,other conservative treatments or alternative methods ofstretching. Data has been presented following a narrativereview format, noting statistically significant differences.A summary of the results for studies with similar com-parators and timescales is provided in Tables 6, 7, 8, 9,10, and 11.
HarmsThree papers [17,19,20] provide details of the presenceor absence of a harmful effect of their interventions; seeTable 4. Hyland et al [17] reported no harmful effectsfrom taping, but made no statement with regards tostretching. Sharma and Loudon [20] report no harmfuleffects. Radford et al [19] reported adverse effects in 10participants within the stretching group. These effectsincluded increased pain in the heel, calf and other areasof the lower limb. There were no adverse effectsreported from the control group.
Pain and function - stretching versus no interventionThree studies compare stretching with no treatment[17] or a placebo intervention [17-19]. Incomplete dataprevented meta-analysis. Wynne et al [18] did not pro-duce independent results for pain and function, butrather grouped them as “symptom severity”.Both Hyland et al [17] and Radford et al [19] reported
improvements in pain over time in the stretchinggroups; reported as statistically significant (p < 0.001) inthe Hyland et al trial (Table 6). However improvementswere also demonstrated in control groups, indicating astrong placebo or non-intervention effect. Hyland et al[17] demonstrated that in comparison to no treatment,the stretching group obtained greater pain relief (p =0.026). However, this same stretching group reported nodifference in pain relief than a group receiving shamtaping (p > 0.05). The study with the highest quality rat-ing on the modified PEDro scale, [19] found no
significant difference in pain relief between stretchingand a control intervention of sham ultrasound (p =0.138).Neither Radford et al [19] or Hyland et al [17]
reported a statistically significant change in the func-tional ability of the participants after completing thestretching intervention, (Table 7). It should be notedhowever, that the data published by Hyland et al [17]shows the mean function of the stretching group tohave declined to a greater degree than the controlgroup; who are themselves described as having a statisti-cally significant decline in function (p = 0.003). Radfordet al [19] reported that both the stretching and controlgroups improved over time with a small improvementin favour of the stretching group, but this was not statis-tically significant (p = 0.052).Wynne et al [18] report an improvement in symptom
relief, (combined score of pain, soreness, stiffness andmobility) in both stretching and control groups immedi-ately following treatment, which consistently reachedstatistical significance in the stretching group (p < 0.05)but only after the first of three treatments in the controlgroup. There was a statistically significant differencebetween groups, in favour of the stretching group twodays post treatment but the authors report that this wasnot maintained. Results from this study were difficult tointerpret. However our observations of charted data wasthat participants in both groups reported similar orworse symptom severity prior to their third treatmentthan prior to their second.
Pain and function - stretching vs another conservativetreatmentTwo studies compared stretching with another treat-ment. Hyland et al [17] found that stretches were lesseffective than calcaneal taping in reducing pain (p =0.006). Sharma and Loudon [20] demonstrated thatstretching or bracing may both reduce pain over time (p< 0.05), however no group differences were demonstrated
Table 6 Summary of shorter-term changes in mean pain scores comparing groups receiving stretches versus thosereceiving no intervention or placebo
Abbreviations: SD = standard deviation#Calculated by current authors or estimated from charts
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in reducing pain on the Foot Function Index (p = 0.77) ormorning pain (p = 0.79). Within their study any reduc-tion in pain due to stretching appears to occur in the firstmonth [20] (Table 8).There was no statistically significant difference
between groups in either study in terms of improve-ment in function (Table 9). Our observation of Hyland’sdata [17] indicates an improvement in function in thetaping group, and a slight decrease in function in thestretching group; reported by the authors as statisticallyinsignificant. Both groups in Sharma and Loudon’sstudy [20] improved over time (p = 0.005). Observationof their data indicates a greater improvement in func-tion in the bracing group one month after completingtreatment [20]. However, Sharma and Loudon [20] usedthe American Orthopaedic Foot and Ankle SocietyAnkle-Hindfoot scale, which incorporates function asjust one component of this outcome measure, and thismay not therefore be a true representation of functionalone.
Pain and function - comparing two types of stretchingOne study [15]) compared different stretching techni-ques. See Tables 10 and 11. DiGiovanni et al [15] com-pared non-weight-bearing plantar fascia stretches withweight-bearing tendo Achilles stretches. Both groupsreported a statistically significant reduction in pain
from baseline to 8 weeks (Table 10). On comparingthe two groups, a significant reduction in two of sevenaspects of pain was reported; pain “at its worst” (p =0.02) and on “first steps in the morning” (p = 0.01)was reported in the group carrying out plantar fasciastretches versus Achilles tendon stretches at the eightweek follow up. There was a similar trend towardsimproved function in the plantar fascia stretchinggroup compared with Achilles tendon stretches ateight weeks (see Table 11), but this did not reach sta-tistical significance (p = 0.058).Porter et al [14] compared 3 minute sustained
stretches with 20-second intermittent tendo Achillesstretches (Tables 10 and 11). Both groups improved interms of pain and function at each of four monthly fol-low up periods. There were, however, no statistically sig-nificant differences between groups for pain (p = 0.315).With regards to function, Porter did report a statisticallysignificant difference in favour of the intermittentstretching group when analysed using mixed-modelrepeated measures ANOVA (p = 0.015). This wasvisually evident to the reviewers in terms of both painand function; we observed a trend in favour of intermit-tent stretches, with the most rapid improvement occur-ring in the first month. However, pair-wise comparisonof the two groups did not show any statistically signifi-cant difference at any one time point.
Table 7 Summary of shorter-term results for changes in mean functional scores comparing groups receiving stretchesversus those receiving no intervention or placebo
Abbreviations: SD = standard deviation.#Calculated by current authors or estimated from charts§See main text for discussion regarding the apparent inconsistency in reported p values between the stretching and control groups
Table 8 Summary of shorter-term results for changes in mean pain scores comparing groups receiving stretchesversus those receiving another intervention
Sharma [20] 10 point visual analogue Stretching #5.3 ## (2.3) 3.5 ## (3.0) #1.75 Not stated
scale at 4 weeks Bracing #5.0 ## (0.8) 3.75 ## (2.3) #1.25 Not stated
Abbreviations: SD = standard deviation.#Calculated by current authors or estimated from charts## Current authors estimation from charts and converting standard error to standard deviation (SD = SE√n)
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DiscussionThe results of this systematic review demonstrate thatpatients with plantar heel pain who stretch tend toimprove over time with regards to both pain and func-tion, but when stretching is compared to other interven-tions, including sham treatment, no statisticallysignificant benefit was observed. In comparison to nointervention, one study [17] demonstrated that stretch-ing was statistically significantly more effective in redu-cing pain, although the clinical significance is debatable.The study gaining the highest PEDro quality rating [19]did not find stretching to be any more beneficial than acontrol intervention. However, the type of stretchingmay be relevant - DiGiovanni et al [15] compared differ-ent stretching techniques, and found stretching of theplantar fascia in non weight bearing, to be significantlymore effective than tendo Achilles stretching in weight
bearing in reducing some, but not all aspects of pain ateight week follow up.Previous reviewers [11] and authors of clinical guide-
lines [1], included just two of the studies in this review[14,15], and concluded that there is some, scientific evi-dence described as moderate quality [1], and poor qual-ity [11] to support the use of stretching for thetreatment of plantar heel pain in terms of short termrelief. Landorf and Menz [4] included two primary stu-dies in their review [15,26] only one of which [15] ful-filled the inclusion criteria for this current review. Theyconcluded that the available evidence was inadequate tosupport stretching exercises as being any more effectivethan other interventions or no intervention in the treat-ment of plantar heel pain. Following our review of sixpapers, we would support Landorf and Menz’s findings[4] that at present there is insufficient evidence to draw
Table 9 Summary of shorter-term results for changes in mean functional scores comparing groups receiving stretchesversus those receiving another intervention
Outcome Group Baseline score(+/- SD)
Follow up score(+/- SD)
Change in meanscore
(+/- SD if available)
Between groupdifference(p value)
Hyland [17] Patient Specific Score at 1 week §Stretching 5.6 (1.1) 4.9 (1.2) #-0.7 0.078
Sharma [20] AOFAS ankle/hindfoot scale at 4 weeks Stretching #64 ##(15) #65 ##(21) #1.0 Not stated
(100 = full function) Bracing #64 ##(5.7) #65 ##(19.8) #1.0
Abbreviations: SD = standard deviation, AOFAS = American Orthopaedic Foot and Ankle Society.#Calculated by current authors or estimated from charts##Current authors estimation from charts and converting standard error to standard deviation (SD = SE√n)§See main text for discussion regarding the apparent inconsistency in reported p values between the stretching and control groups
Table 10 Summary of changes in mean pain scores for groups receiving different types of stretches
Outcome Group BaselineScore
(+/- SD)
Follow upscore
(+/- SD)
Change in meanscore
(+/- SD) ifavailable
Between groupdifference(p value)
Giovanni [15] Pain(100 mm visual analogue scale)
sub-scale of Foot Function Index(0 = no pain)
Weight bearingAchilles stretch
Not stated Not stated Pain at worst-14.7 ##(+/-19.9)
1st am steps-13.2 ##(+/-27.7)
Combined painscore
-13.0##(+/-20.8)
Pain at worstp = 0.02
#Mean 11.31st steps in morning
p = 0.006#Mean 17.9
Combined scorep > 0.05
#Mean 6.0
Non weightbearing plantarfascia stretch
Not stated Not stated Pain at worst-26.0 ##(+/-24.3)
1st am steps-31.1 ##(+/-28.8)
Combined pain score-19.0 ##(+/-19.9)
Porter [14] Foot and ankle pain score Sustained 57.5 (20.1) 79.7 (17.5) #22.2 P = 0.315
(100 = no pain) Intermittent 53.5 (22.0) 82.5 (15.2) #29.0
Abbreviations: SD = standard deviation, SE = standard error.#Calculated by current authors or estimated from charts##Current authors estimation from charts and converting standard error to standard deviation (SD = SE√n)
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any conclusions about the comparative effectiveness ofstretching.The relatively small number of participants evaluated
in most of the studies may have influenced the results ofthis review. Although there was a trend for an improve-ment in participants who underwent stretching, only onestudy [17] demonstrated a statistically significant differ-ence between stretching and a control treatment. Thestudy with the highest PEDro quality rating [19] did notfind their stretching programme to be any more effectivethan sham ultrasound. This was the only study to reportthe use of a power calculation in selecting their studysample size. Other studies, in particular those with smal-ler samples, may have suffered from a type II error inwhich potential differences between groups are notdetected due to inadequate power. It therefore remainsunclear whether stretching exercises are more effectivethan other treatments or no treatment in the manage-ment of plantar heel pain. We recommend that samplesizes for future studies are pre-specified and based onappropriate power calculations.It is important to note the difference between statistical
significance and clinical significance [27]. The only studydemonstrating a statistically significant differencebetween stretching and a control treatment [17], used avisual analogue scale evaluating pain on first steps in themorning, and reported a mean improvement in thestretching group of 1.7 on a scale of 0-10. Research hasrecently been undertaken evaluating a similar scale [28],and it was concluded that the minimal important differ-ence in score required for a patient with plantar heelpain to perceive benefit from treatment, was an improve-ment of 19 mm on a 100 mm scale. On this basis, theclinical significance of the improvements demonstratedby Hyland et al [17] can be questioned.The length of follow up time varied from 1 week [17]
to 4 months [14]. This has the potential to influence theresults and other factors such as dropout rates. Thisinfluence may be reflected in the results; the study with
the shortest follow up time was the only one to report astatistically significant benefit to stretching in compari-son to a control or other intervention and had a dropout rate of only 2%. In comparison, the studies with thelongest follow up periods [14,20], reported results thatwere not statistically significant, and had the highestdropout rates of 21% and 24% respectively (see Table 4).Subject characteristics may have played a role in
response to treatment. The duration of symptoms variedbetween and within studies. In one paper, this rangedfrom 3 to 121 months [19]. Other chronic conditionssuch as back pain have been shown to be less likely torespond to treatment [29], and this variation may havean impact on the success of any intervention. Researchinvestigating the influence of the duration of plantarheel pain on its responsiveness to treatment, may there-fore be helpful to those evaluating the effectiveness oftreatment modalities in the future.The specific anatomical structure under stretch may
have influenced the effectiveness of the technique. Onestudy [15] compared two different stretches (plantar fas-cia stretches and tendo Achilles stretches). A significantreduction in pain “at its worst” (p = 0.003) and on “firststeps in the morning” (p = 0.01) was reported in thegroup carrying out plantar fascia stretches in comparisonto tendo Achilles stretches at eight weeks. The onlypaper to show a statistically significant benefit fromstretching over a control intervention [17] used a plantarfascia stretch in combination with a stretch to the calfmuscles. The highest quality study [19] did not find anybenefit from a tendo Achilles stretch in isolation whencompared to a control intervention. This may suggestthat in the short term at least, plantar fascia stretching ismore effective than tendo Achilles stretching in isolation.There was considerable variation in the frequency of
the stretching techniques applied (Table 5). This factoralone may have influenced results and makes directcomparison difficult. The one study that found a statisti-cally significant benefit from stretching in comparison to
Table 11 Summary of changes in mean functional scores for groups receiving different types of stretches
Outcome Group Baselinescore
(+/- SD)
Follow upscore
(+/- SD)
Change in meanscore
(+/- SD)if available
Between groupdifference(p value)
Giovanni[15]
Function Index Weight bearing, Achilles stretch Not stated Not stated -8.3 ##(16.6) 0.058
(0 = full function) Non weight bearing, plantarfascia stretch
Abbreviations: SD = standard deviation, SE = standard error.#Calculated by current authors or estimated from charts##Current authors estimation from charts and converting standard error to standard deviation (SD = SE√n)
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a control group [17] did the least number of stretches(two sessions in a week). Other studies [14,15,19,20],however, did also demonstrate some improvement inpain compared to alternative or control interventions,but these improvements were not statistically significant.Therefore, the available evidence does not allow anyfirm conclusions to be made regarding the optimal fre-quency of stretches.There was a wide variation in the duration of stretch
applied, ranging from ten seconds [15] to three minutes[14]. One study [14] specifically compared sustainedstretching for three minutes with intermittent stretchingfor twenty seconds and found no statistically significantdifference between the two groups, although the poten-tial for significant difference in terms of increased func-tion was reported using the mixed method repeatedANOVA. The position that the stretches were per-formed in also varied. In two studies the participantsstretched in a weight-bearing position, in two they werein a non-weight bearing position and in another studyone intervention group was weight bearing and one wasnon-weight bearing [15]. Although the non-weight bear-ing stretch did show some significant improvementsover the weight bearing stretch in the latter study, thedifference in the anatomical structure being stretched(plantar fascia versus tendo Achilles) limits any conclu-sions in this respect. It appears that no clear conclusionscan be drawn regarding the most effective stretch dura-tion, or position.Another source of variation was the number of repeti-
tions that the participants in each study were asked toperform. The highest number of repetitions was 210 perweek [15], and the lowest number was 6 per week [17].This is clearly a wide range, and is likely to have aninfluence on the outcome. However, whilst the studywith the lowest number of repetitions found a statisti-cally significant difference, the study with the highestrepetitions [15] also found some improvements in painscores. Obviously no clear conclusions can be drawnregarding the optimum number of repetitions.In four of the studies [14,15,19,20], the participants
implemented the stretches themselves; in the two addi-tional studies the therapist applied the stretch [17,18].The highest quality study [19] used self-applied stretch-ing and found it no more effective than a control inter-vention. No studies compared self-stretches withtherapist-applied stretches and this is an aspect thatmay benefit from further research and cost benefitanalysis.Four studies used a visual analogue scale for measur-
ing pain, [15,17,19,20] and demonstrated that between 1week and two months of commencing a stretching pro-gramme there is a decrease in pain, although the effec-tiveness of stretches in reducing pain may not be above
that of a control group [17,19] or alternative treatment[17,20]. DiGiovanni et al [16] did carry out a two yearcase series in which participants from the Achillesstretching group, joined participants from the plantarfascia stretching group in carrying out plantar fasciastretches for a further two years. Although an improve-ment in pain relief continued, the absence of a controlgroup limited any conclusions that could be drawnabout the benefit that might be gained from continuingto stretch for a longer period. Also as plantar heel painmay be self-limiting [4], the continued improvementdescribed by DiGiovanni et al [16] may simply representthe natural history of the disorder.Four studies measured functional ability [14,17,19,20]
as an outcome after stretching. Porter et al [14] reporteda potentially significant improvement in functional abil-ity, but not pain at monthly follow up periods for 4months in favour of intermittent 20 second stretchesversus sustained 3-minute stretches. Their study did notinclude a control or alternative treatment group. Thestudy with the highest methodological quality ratingusing the PEDro score [19], found a trend (p = 0.052) infavour of the stretching group over the control groupfor the function sub-scale of the Foot Health Question-naire at two week follow up. Sharma and Loudon [20]used the American Orthopaedic Foot and Ankle SocietyAnkle-Hindfoot scale, and found significant improve-ments 4 weeks after completion of an 8 week stretchingprogramme (p = 0.005), but function is just one of com-ponent of this outcome measure and there was no dif-ference between this and the results from a group usingbracing (p = 0.78). Conversely, Hyland et al [17] showeda negative trend with regards to function at one weekfollow up in the stretching group. This negative trendmight be as a result of the shorter follow up time uti-lised by Hyland et al [17]; which might not be an ade-quate period to detect functional changes. However, aspreviously mentioned, although described as not statisti-cally significant, the data published by Hyland et al [17]shows the mean function of the stretching groupdeclined to a greater degree than the control group;who were themselves found to have experienced a sig-nificant decline in function (p = 0.003). Whilst painrelief is likely to be a primary goal of treatment for peo-ple suffering from plantar heel pain, improvement infunction is equally crucial. With this in mind, an impor-tant question was unable to be fully answered by thisreview.Only six eligible studies were retrieved. Having such a
small number of studies within a systematic review maylead to misleading conclusions. This does highlight theneed for further adequately powered randomised con-trolled trials. The internal validity of future studieswould be enhanced by allocation concealment and
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blinding of assessors. Future studies should also includepresentation of mean differences and measures of varia-bility, (e.g. standard deviations or 95% confidence inter-vals) in outcome scores pre and post treatment for eachgroup. This would allow results to be attributed to theintervention rather than the passage of time and allowmeta-analysis.Certain limitations of this review must be acknowl-
edged. Firstly the search strategy relied exclusively oncomputer databases and no hand searches were underta-ken, thus relevant papers may have been missed.Although the search attempted to identify unpublishedresearch, it is possible that some relevant pieces of greyliterature (such as university theses) were not uncovered.Any exclusion of unpublished work that may subse-quently have occurred increases the possibility of report-ing or publication bias. This review only included paperspublished in English. This again may have resulted inthe exclusion of relevant research. Appropriate cautionshould therefore be applied when interpreting theresults of this systematic review.
ConclusionsIt cannot be stated from the currently available evidencethat stretching is any more effective than other interven-tions or control groups in relieving plantar heel pain.The main pain-relieving benefits of stretching appear tooccur within the first two weeks to four months. Thereis no conclusive evidence regarding the most effectivenumber of repetitions or frequency of stretching, orwhether self or therapist applied stretches are mosteffective. Inclusion of stretches directly to the plantarfascia may provide better short-term pain relief thanstretching the tendo Achilles alone, but further investi-gation is required to confirm this. There is a need forfurther research regarding this topic in the form of suffi-ciently powered randomised controlled trials, utilizingvalidated outcome measures for the measurement offunctional changes, blinded assessors and with bothmedium and long-term follow up.
AcknowledgementsThank you to Dr David Porter for responding to our request and providingfurther details of results. Thank you to the reviewers for their time inpreparing constructive comments and suggestions to help refine the paperprior to publication.
Author details1Faculty of Medicine and Health Sciences, University of East Anglia, Norwich,Norfolk, NR4 7TJ, UK. 2Physiotherapy Department, NHS Great Yarmouth andWaveney, 1 Common Lane North, Beccles, Suffolk, NR34 9BN, UK.3Physiotherapy Department, Norfolk and Norwich University NHS HospitalFoundation Trust, Colney Lane, Norwich, Norfolk, NR4 7UY, UK.
Authors’ contributionsDS contributed to the literature search, data extraction, analysis and draftingof the manuscript. BP contributed to the literature search, data extraction,
analysis and drafting of the manuscript. LH contributed to the literaturesearch, data extraction, analysis and drafting of the manuscript. RCcontributed to the data extraction, analysis and drafting of the manuscript.All authors read and approved the final manuscript.
Competing interestsThe authors declare that they have no competing interests.
Received: 19 January 2011 Accepted: 25 June 2011Published: 25 June 2011
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doi:10.1186/1757-1146-4-19Cite this article as: Sweeting et al.: The effectiveness of manual stretchingin the treatment of plantar heel pain: a systematic review. Journal of Footand Ankle Research 2011 4:19.
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