Muscular activity patterns in 1-legged vs. 2-legged pedaling

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• One-legged pedaling is relevant for elite cyclists and clinical applications.
• Understanding muscular demands in one-legged versus two-legged cycling is incomplete.
• This study investigates muscle activation differences between one- and two-legged pedaling.

Purpose of the Study:

• To analyze how leg muscle activation patterns change during one-legged pedaling compared to two-legged pedaling.
• To quantify differences in muscle activity across the crank cycle quadrants.
• To elucidate the neuromuscular strategies employed during unilateral cycling.

Main Methods:

• Fifteen healthy recreational cyclists participated in the study.
• Participants performed both one-legged and two-legged pedaling trials at a standardized power output (approx. 30 Watts per leg).
• Surface electromyography (sEMG) recorded activity from 10 major left leg muscles, with data processed for each crank cycle quadrant.

Main Results:

• One-legged pedaling reduced downstroke torque and extension muscle activity (vastus lateralis, vastus medialis, soleus).
• Flexion-related muscles (hamstrings, gastrocnemii, tensor fasciae latae, tibialis anterior) increased activity during the upstroke to compensate for the absent contralateral leg.
• Greater hip flexor activity was observed at the top of the crank cycle for pelvic stabilization.

Conclusions:

• Changes in muscle activation during one-legged pedaling are attributed to altered mechanical factors.
• These factors include modified crank torque, reduced pelvic stability, and increased knee/ankle stiffness during the upstroke.
• These findings highlight the neuromuscular adaptations required for unilateral cycling performance.