Muscle activity increased after co-contraction resistance training, but it was unrelated to the rating of perceived exertion in older adults

BACKGROUND: Evaluating exercise intensity is crucial for designing effective training programs and monitoring progress. The Rating of Perceived Exertion (RPE) scale, a subjective measure of effort, is commonly used for estimating exercise intensity. However, its applicability in specific conditions and populations, particularly in co-contraction training and older individuals, warrants further investigation. AIM: Our main aim was to analyze the correlation between RPE and electromyographic (EMG) activity in co-contraction and conventional resistance training. We also compared muscle activity and RPE across training methods. METHOD: Twenty-three older adults were allocated and divided into conventional resistance training (CRT) and co-contraction training (CCT). EMG activity and RPE were recorded for knee extension and flexion movement and knee co-contraction during training sets and correlated before and after eight weeks of training. RESULTS: The results indicated no significant correlation between EMG activity and RPE for either training method. Additionally, EMG analysis showed higher EMG activity in the CRT than in the CCT. On the other hand, CCT demonstrated an increase in EMG activity after eight weeks of training. CONCLUSION: In conclusion, RPE did not correlate with EMG activity, highlighting the need for finding accessible tools to assess exercise intensity, particularly in older people, and alternative training methods, such as co-contraction training.