Estimating training intensity for low-intensity resistance training using surface electromyography

BACKGROUND: Generally, resistance training is performed to improve muscle atrophy and increase muscle mass among various populations. Low-load resistance training for the quadriceps muscles, including knee extensions, squats, sit-to-stand maneuver, and stair ascent and descent, has been performed in rehabilitation settings. However, the training intensity for the exercises have remained unclear for young and older populations undergoing rehabilitation. The aim of this study was to investigate quadriceps muscle activity during these resistance training exercises, which are frequently performed by young and older community-dwelling adults undergoing rehabilitation and determine training intensity.METHODS: A total of 26 healthy young adults and 24 older community-dwelling participants participated in this study. Surface electromyography measurements were recorded from the right rectus femoris and vastus lateralis during low -load resistance training and knee extension exercise and were averaged for further analysis and named quadriceps femoris activity.RESULTS: Our results showed that resistance training intensity was less than 40% of 1 repetition maximum in both young and older adults.CONCLUSIONS: Our outcomes suggested that the low-intensity resistance training program investigated in this study may be insufficient for increasing muscle strength and mass among both young and older adults.