Cycling: joint kinematics and muscle activity during differing intensities

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Cycling workloads influence full body kinematics and electromyographic (EMG) patterns.
• Understanding these changes is crucial for optimizing cyclist training, racing, and injury prevention.

Purpose of the Study:

• To assess how varying exercise intensities (60%, 80%, 90% max heart rate) affect lower limb EMG and full body 3D kinematics in well-trained cyclists.
• To provide data for clinicians and bike fitters to enhance muscle strength and cycling posture.

Main Methods:

• 17 well-trained cyclists participated in the study.
• Full body 3D kinematics and lower limb EMG were measured at three distinct exercise intensities.
• Data analysis focused on changes in joint angles and muscle activation patterns.

Main Results:

• Significant kinematic alterations were observed in the ankle, knee, elbow, lumbar, and thoracic spine joints with increasing intensity.
• Ankle dorsiflexion and knee extension increased by 6-9% at higher intensities.
• Elbow flexion increased by 39%, and lumbar/thoracic flexion by 7% from 60% to 90% intensity.
• EMG signal amplitude significantly increased in all measured muscle groups at higher intensities.

Conclusions:

• Increased cycling intensity leads to significant changes in full body kinematics and muscle activation.
• These findings support targeted muscle strengthening and inform bicycle fitting adjustments based on intensity.
• Clinicians and bike fitters can use this data to optimize cycling performance and posture.