Repeated Kicking Actions in Karate: Effect on Technical Execution in Elite Practitioners

Area of Science:

• Sports Science
• Biomechanics
• Kinesiology

Background:

• Martial arts training often involves repetitive technical actions.
• Continuous repetition may impact technical execution and training effectiveness.
• Understanding kinematic and muscle activation changes is crucial for optimizing training.

Purpose of the Study:

• To investigate how repeated roundhouse kicks affect lower-limb kinematics and muscle activation in karate practitioners.
• To determine if task repetition alters technical execution, potentially limiting training efficacy.
• To analyze changes in hip and knee movement and muscle activity during a sequence of kicks.

Main Methods:

• Six junior karate athletes performed 20 continuous roundhouse kicks.
• Recorded hip and knee kinematics and electromyography (EMG) of vastus lateralis, biceps femoris (BF), and rectus femoris.
• Analyzed peak angular displacements/velocities and muscle activation, computing median frequency for myoelectric fatigue assessment.

Main Results:

• Significant decreases observed in knee flexion, BF median frequency, hip abduction, knee-extension angular velocity, and BF antagonist activation.
• A significant increase in hip flexion was noted during the repetition sequence.
• These findings indicate technique adaptation and muscle fatigue during repeated kicking.

Conclusions:

• Karate competitions demand precise technical execution, necessitating careful design of training protocols that combine fatigue and technical actions.
• Athletes adapt their technique under fatigue, which can impact performance.
• Recommendations include specific strength training for knee flexors, particularly the biceps femoris (BF).