Effect of power output on muscle coordination during rowing

Area of Science:

• Biomechanics
• Motor Control
• Sports Science

Background:

• Understanding how varying exercise intensity affects muscle activation and coordination is crucial for optimizing training and performance.
• Rowing involves complex multi-joint movements where muscle synergies play a key role in efficient execution.

Purpose of the Study:

• To quantify the impact of different power outputs on muscle coordination during rowing.
• To investigate changes in muscle synergies and electromyographic (EMG) activity across varying exercise intensities.

Main Methods:

• Surface electromyography (EMG) of 23 muscles and mechanical variables were recorded in untrained and experienced rowers.
• Subjects performed rowing exercises at 60%, 90%, and 120% of their mean power output.
• Nonnegative matrix factorization was employed to extract and analyze muscle synergies.

Main Results:

• A significant increase in EMG activity was observed for most muscles as power output increased (p < 0.004).
• Individual EMG patterns and activation timing showed minimal changes across power outputs (mean r = 0.93).
• Extracted muscle synergies demonstrated high consistency in activation coefficients and muscle synergy vectors across different power loads.

Conclusions:

• While muscle activity levels increase with power output, the overall temporal and spatial organization of muscle coordination in rowing is minimally affected.
• The identified muscle synergies provide a stable framework for motor control during rowing, regardless of intensity.