Comparison of Resistance Exercise Perceived Exertion and Muscle Activation at Varied Submaximal Durations, Loads, and...

Area of Science:

• Exercise Physiology
• Biomechanics
• Sports Science

Background:

• Previous research on muscle activation during dynamic contractions often overlooked differences in strength between concentric (CON) and eccentric (ECC) actions.
• Understanding how varying exercise parameters affect perceived exertion and muscle activation is crucial for optimizing training protocols.

Purpose of the Study:

• To investigate the impact of different dynamic muscle contraction durations (2-5 seconds), loads (30-70% of 1RM), and contraction types (CON vs. ECC) on perceived exertion and muscle activation in women.
• To analyze differences in perceived exertion and electromyography (EMG) amplitude under varied submaximal resistance exercise conditions.

Main Methods:

• Six women performed leg extensions at 30%, 50%, and 70% of their CON and ECC one-repetition maximum (1RM) for durations of 2, 3, 4, and 5 seconds.
• Rating of Perceived Exertion (RPE) and EMG root mean square amplitude were recorded during the knee extension exercise.
• Participants received auditory and visual feedback to control contraction speed and duration.

Main Results:

• Rating of Perceived Exertion (RPE) significantly increased with higher loads (30%, 50%, 70%) and longer time under tension, irrespective of contraction type (CON/ECC).
• Electromyography (EMG) amplitude also increased with load but showed less distinction across different contraction durations (2-5 seconds).
• The study identified distinct effort perceptions in women at submaximal knee extension loads.

Conclusions:

• Higher loads and increased time under tension are key drivers of perceived exertion during resistance exercise in women.
• Contraction duration has a less pronounced effect on muscle activation compared to load.
• These findings can inform the development of resistance training programs that enhance exercise adherence by optimizing load, duration, and contraction type for positive user experience.