MAP ManualSoccer pass kick video analysisSPSC 1151 - 002

Simrin Hundal

Andrew De Los Reyes

Robert Calder

Nicolai Hartmann

Table of Contents

1) Introduction

2) Equipment and set up

3) Sequence of a pass kick movement

4) Dartfish Video Analysis

5) Data analysis value table

6) Analysis of Critical features of a soccer kick

7) Analysis comparison to research

8) implications and training suggestion

9) Limitations

10) References

Introduction

Goal of this video analysis:

Analysis of a soccer pass kick in a right footed kicker

identify, analyze and compare 3 critical features of a pass kick to research findings

critical features of hip, knee and ankle that are the focus of this analysis:

Angular displacement

Angular velocity

Linear velocity

Speed of foot at impact and ball velocity

Provide coaching suggestions to improve pass kick performance

Equipment Required

motion tracking Camera :60Hz

Reflector Markers

Tape measure: 30 feet in length

Tripod

Black backdrop

Lights

Masking tape

Metre stick

Soccer ball

Performer Details

A performer who is familiar with a soccer kick and proper techniques required for that kick

Must wear tight black clothing and black shoes. Black long sleeve shirt is preferred as it allows the reflectors to be seen better. This attire allows for movement to be seen more clearly.

Equipment Setup

1) Use the black mats on the gym wall as the back drop. If none are available tape a black sheet on the wall.

2) Place 9 markers placed 1 metre apart vertically and horizontally from each other to use as reference points.

3) Attach reflectors on the side of the participant’s respective joints in the sagittal view in the direction of the camera. (shoulder, elbow, wrist, hip, knee, ankle and foot)

Equipment Setup continued

4) Set up the camera and tripod 10 meters away from wall. Make sure it is as far away as possible while being in focus to ensure the best field of view. Level the tripod by adjusting legs

5) Make sure the camera is perpendicular (90 degrees) to the kick, to get an acurate view of all angles and measurements in the sagittal plane.

6) Setup the camera by selecting the frame rate to be 400 fps.

Equipment Setup continued

7) Place additional lights behind the camera to better illuminate the area that is being filmed. If the cord cannot reach behind the camera and an extension cord is not available, place the lights to the side opposite of where the ball will be kicked to.

8) place the ball 1 metre away from the wall perpendicular to the spot of the third marker (center of wall markings)

Equipment Setup continued

9) allow the performer to practice the kick at least three times to ensure they feel comfortable and warmed up.

10) Have performer kick while recording on camera. Ensure the kicker does not go out of the camera’s view.

11) record at least 3 kicks which will give you the option to chose the best kick to analyze.

Sequence of a right legged pass kick movement

For video analysis it is important to understand the movement of a soccer Kick

A soccer pass kick can be separated into 4 Phases:

Airborne Phase

Includes approach run that starts when thrusting off ground with right foot

Approach run ends when left heel touches down

Ground support phase can be split into two phases

Heel support phase

Lasts from landing of the heel until landing of the toe

Full support phase

Lasts from complete landing of the toe until impact with the ball

Airborne PhaseApproach run start / approach run end

Heel support phase(landing of heel – landing of toe)

Full support phase(landing of toe – impact w/ ball)

Ground support phase(Landing of left foot – impact w/ ball)

Sequence of a right legged

pass kick movement

Using Dartfish to analyze a pass kick Analyzing a video of a performance using Dartfish:

Choose video to analyze

Insert video into dartfish bar

Measure angular displacement:

Use menu bar on the right

Scroll over the angle sign and left click on it

Attach points of the angle on points of the joints

that should be evaluated

Right click on the angle lines that appear and choose

slow tracking under the tracking menu

The lines will track the angle of the chosen joint throughout video

Manually adjust tracking of angles frame to frame if necessary.

For precise value calculation it is necessary to create

a distance line.

right click on angles symbol and left click on distance

Drag distance line between markers in the video to define distances

Using Dartfish to analyze a pass kick

Analyzing a video using Dartfish cont. :

To track angles it is necessary to first create a data table

Right Click on the table symbol in the menu

Choose data table and drag table into the screen at preferred size

Left click on the angle lines on the joint, then right click into the bottom

Field of the data table and choose “Display angle in this

Column” > angles will be tracked

Run the video again to track angles and record values in the table.

To track linear velocities do the same but choose

“Display x-coordinate of 2nd Drawing in this column” instead

Add a column for interval or average speed to display linear

Velocity by right clicking on data table and choose “insert

Interval column”

Using Dartfish to analyze a pass kick

To track linear velocity of the ball first a marker must

be placed on the ball.

Choose the plus symbol/marker symbol in the

left-hand menu by right clicking on it and left click on

marker.

Place marker directly on ball. Right click and

choose “slow tracking”. Manually adjust positioning

of the marker onto the ball if necessary throughout

the video.

create a data table and choose a column

displaying “average speed” to display linear velocity values.

To export data into an excel table right click on data table and choose export table, which

Opens a window to save an excel spreadsheet of the tracked data.

angular velocity can then be calculated using the data in the excel spreadsheet and applying the formula for angular velocity

Overview of Data Analysis values

Analysis of critical features in pass kick including research findings

For the purposes of this analysis it is important to note that angles in the research findings were measured as Cardan angles (zero anatomical position as reference point) (Levanon & Dapena (1998)).

Relative angles seen in the previous value table for this comparison were converted into Cardan angles using the zero anatomical position.

Angular displacement

The hip angles in the performance varied from – 18.8 degrees at point of landing of the heel to -4.9 degrees at point of landing of the toe which varies by 2% from the angles of -5 degress to – 19 degree that Levanon & Dapena found (1998).

The knee angles were measured at -27.1 degrees at take-off and – 105.5 at max knee flexion, which varied by 25% at take-off and was nearly identical at max flexion of the knee compared to the -36 degrees at take off and – 105 degrees that Levanon and Dapena (1998) found.

The ankle was measured at 78.6 deg in dorsiflexion at impact which varied by 12.4 degrees or 14% from the research findings of Levanon and Dapena (1998)

Angular Velocity

Hip max. angular velocity was measured at 600 deg/s which varied roughly 25% from the research findings and angular velocity at impact changed to 136 deg/s, which was 41% less than in the research of Levanon & Dapena (1998).

Max angular velocity of the knee was measured at 1075 deg/s at point of impact with the ball and differed by a mere 9% from research findings which was found at 1180 deg/s (Levanon & Dapena (1998)).

Analysis of critical features in pass kick including research findings cont.

Linear Velocity

Max. Ball velocity was measured at 21.2 m/s compared to 22.5 m/s in the research.

Speed of the foot was measured at 17.26 m/s at impact compared to 18.3 m/s in the research findings, which is 1.04 m/s slower (6%slower).

Ratio of speed of ball to speed of foot was measured at 1.25:1 , which varies from the research findings by 0.02 (1.23:1) or 1.6%.

Results of analysis comparison

Performance of the pass kick resulted in very similar measurements to the measurements in the research findings. Therefore performance of the pass kick was good and only a few adjustments and training suggestions have to be made.

The angles of the knee and hip displayed the highest similarity to the research findings with near identical measurements. Therefore movement of the hip and knee was done well in the performance.

The ankle displayed most variation by showing 14% less dorsiflexion compared to the research. This means that there was more movement in the ankle compared to the research.

Angular velocity of the knee shows most similarity to the research findings and only varied by 9%. Therefore Knee movement was performed accurately to produce the wanted angular velocity to perform a skillful pass kick.

The hip showed some variation and was measured with a variation of 25% less max. angular velocity and 41% less angular velocity at impact with the ball. This means that the hip movement was significantly slower at impact than the research findings suggested.

The Velocity of the ball was nearly identical to the research and speed of the foot nearly identical in the performance to the research findings and only differed by 1.6% or 1.04 m/s

Therefore speed of the foot slowed down in the pass kick just as it did in the research just before impact to produce ball velocity, but keep accuracy high.

Results of analysis comparison cont.

Movement of the pass kick was for the majority of the kick done well with minor variations from what research suggests.

The major differences between the pass kick performance and research findings were :

hip angular velocity at impact with the ball was significantly (41%) slower than in research ( Levanon & Dapena (1998)).

ankle dorsiflexion was 14 % more flexed in the performance compared to the findings of Levanon & Dapena (1998).

Implications and future suggestions for performer

The slower hip angular velocity into extension suggests that the hip was extended slower in the performance compared to the research to get into a position to accurately perform a pass kick.

Nonetheless the final angles did not differ significantly.

This could suggest that the performer took longer to adjust and may need to work on perfecting the skill to adjust the hip faster and get into a stable position.

Faster adjustments could be beneficial in competitive settings, in which an individual has to adjust quickly to game situations.

Core strength training and functional training that include stability could improve balance and hip movement.

Implications and future suggestions for performer

The ankle of the kicking foot was more flexed than what research suggests it should be for a skillful pass kick performance.

Specific training focusing on reducing ankle dorsiflexion during the pass kick could help in improving pass kick performance and accuracy

Limitations

Movement of the ankle was difficult to measure precisely using Dartfish due to the lower Hz camera used. The lower Hz use blurred the picture in very quick movements even when moving frame to frame.

Therefore tracking angles was not 100% precise.

A higher Hz camera might result in more precise measurements of the ankle and might result in different final measurements of the angles of the ankle due to more frames being available.

References

Levanon, J., & Dapena, J. (1998). Comparison of the kinematics of the full-instep and pass kicks in soccer. Medicine & Science in Sports & Exercise, 30(6), 917-927.