3D-Biomechanical Analysis of the Soccer Kick

Introduction• We chose to look at the biomechanics of

the soccer kick

• Two different kicks were looked at:– The straight kick– The sweep kick

Purpose & Objectives• We sought to look at the angular

velocities, moments and powers at the hip and knee joints

• The different contributions of the specific muscle groups for each of the kicks

Literature reviewed• Majority of previous studies have focused

on the kinematics• Very few studies have performed 3-D

analysis, those that have did kinematics only

• Previous studies found:– hip flexion followed by hip extension moment produces knee

extension, not the knee extensors– Knee flexors are active during knee extension to prevent

hyperextension(study by D.G.E. Robertson, C. Fernando, M. Hart & F. Beaulieu)

Methods• The motion was captured

using the Vicon® motion capture system

• 5 infrared cameras were used at a sampling rate of 100Hz. The data was filtered using a Woltring GCV filter

• A 28-marker set was used as illustrated left

Methods• The different kicking styles were analyzed for

moment forces and power.• The first style looked at was the straight kick-

where the athlete approaches the ball straight on.

• The next style was the sweep kick- where the athlete approaches the ball from the side.

• Subject was a male 22 year old experienced soccer player

• Performed 4 trials of each kick, and we attempted to analyze the best trials

Straight Kick• Approaching the ball

straight on

• Mostly a flexion/extension action

• Minimal abduction/adduction

Sweep Kick• Approaching the ball

at an angle

• Substantial abduction/adduction components

Joint Power Analysis (Flexion/ Extension) Straight Kick

• Hip:Extension is negativeFlexion is positive

• Knee:Extension is positiveFlexion is negative

Moment power(W)Positive = concentricNegative = eccentric

Joint Power Analysis (Flexion/ Extension) Sweep Kick

• Hip:Extension is negativeFlexion is positive

• Knee:Extension is positiveFlexion is negative

Moment power(W)Positive = concentricNegative = eccentric

Joint Power Analysis (Abduction/ Adduction) Sweep Kick

• Hip:Extension is negativeFlexion is positive

• Knee:Extension is positiveFlexion is negative

Moment power(W)Positive = concentricNegative = eccentric

Analysis Summary• The hip flexors and extensors are

responsible for producing the majority of the kicking force

• During knee extension, the flexors are active just before strike preventing hyperextension

• Hip extensor action just prior to contact is what initiates knee extension

Analysis Summary• The abduction/ adduction curves follow a

similar path to the flexion/ extension graphs.

• The magnitudes of the abduction/ adduction are substantial for the velocities and moments, but much smaller for the powers.

• Anatomical structures resist moments thus reducing powers

Conclusions and Recommendations

• Our results supported the previous studies concerning the powers and forces for flexion/ extension

• Our abduction/ adduction results were what we expected based on anatomical predicions

• Some studies have shown that the sweep kick produces higher ball velocities, possibly due to the added abduction/ adduction forces of the limb.

• Now that more 3D capture technology is available more kinetic studies should be done.