Intra-session repeatability of lower limb muscles activation pattern during pedaling

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• Assessing intra-session repeatability of muscle activation patterns is crucial for research, particularly for detecting changes over time.
• The reliability of lower limb muscle activation patterns during cycling, a common exercise, requires further establishment.

Purpose of the Study:

• To evaluate the intra-session repeatability of muscle activation patterns in 10 lower limb muscles during sub-maximal cycling.
• To assess both muscle activity level and activation timing for key cycling muscles.

Main Methods:

• Eleven triathletes performed a reference cycling exercise (150 W) before and after a simulated training session (200 W).
• Electromyography (EMG) recorded activation patterns (RMS, burst onset/offset) for gluteus maximus, hamstrings, quadriceps, gastrocnemius, soleus, and tibialis anterior.
• Repeatability was analyzed using ICC, SEM, and cross-correlation coefficients.

Main Results:

• No significant differences in muscle activation levels were observed between test and retest for any muscle.
• Significant differences in activation timing were found only for vastus medialis, soleus, and tibialis anterior.
• Cross-correlation analysis indicated good repeatability for activation timing across all studied muscles.

Conclusions:

• The electromyography (EMG) patterns during pedaling demonstrate good intra-session repeatability for both muscle activity level and activation timing.
• These findings support the use of EMG for reliable assessment of lower limb muscle function during cycling research.