Cycling: joint kinematics and muscle activity during differing intensities.

Full body kinematics and electromyographic (EMG) patterns may alter based on the workloads that are encountered during cycling. Understanding the effect of differing intensities on the cyclist can guide clinicians and bike fitters in improving specific muscle strength and cycling posture to optimise training and racing. We aimed to assess changes in lower limb EMG magnitudes and full body 3D kinematics of 17 well-trained cyclists at three different exercise intensities: 60%, 80% and 90% of maximum heart rate. Significant results were demonstrated for all the joints except the hip and shoulder. Cyclists' ankle dorsiflexion and knee extension increased between 6% and 9% with higher intensities. The elbow adopted a significantly more flexed position, increasing flexion by 39% from 60% to 90% intensity, whilst the lumbar and thoracic flexion increased by 7% at the higher intensity. There were significant increases in EMG signal amplitude at higher intensities for all muscle groups measured. These results will guide clinicians in strengthening specific muscles at specific ranges of the cycling pedal revolution. Guidelines for optimal bicycle configuration should take into account the full body position of the cyclist as well as the training and racing intensity when assessing kinematics.