EMG activity does not change during a time trial in competitive cyclists

Area of Science:

• Sports Science
• Exercise Physiology
• Biomechanics

Background:

• Understanding muscle activation patterns is crucial for optimizing cycling performance.
• Electromyographic (EMG) analysis provides insights into neuromuscular control during endurance events.
• Previous research has explored muscle fatigue during cycling, but steady-state conditions require further investigation.

Purpose of the Study:

• To measure electromyographic (EMG) activity of four lower limb muscles during a cycling time-trial (TT).
• To assess the relationship between EMG activity and propulsive torque throughout the TT.
• To determine if cyclists achieve a muscular work steady-state during a self-selected intensity TT.

Main Methods:

• Nine elite cyclists completed a 30-minute cycling TT on a cycle ergometer.
• EMG activity of vastus medialis, rectus femoris, biceps femoris, and gastrocnemius medialis was recorded.
• Propulsive torque and pedaling cadence were measured concurrently.

Main Results:

• No significant time-dependent changes were observed in power output, cadence, or mean propulsive torque.
• EMG activity of vastus medialis and rectus femoris remained constant.
• EMG activity of biceps femoris and gastrocnemius medialis showed a non-significant trend of increase.
• EMG/torque ratio for vastus medialis and rectus femoris showed a non-significant trend of decrease.

Conclusions:

• Cyclists likely performed the 30-minute TT at a muscular work steady-state.
• The investigated lower limb muscles did not exhibit significant fatigue-related increases in EMG activity.
• Findings suggest a stable neuromuscular recruitment strategy during prolonged, self-paced cycling efforts.