Re-examining the concept of the “resistance training effect” in older adults

Traditionally, skeletal muscle health in older people has been focused primarily on the loss of muscle mass. However, there are several aspects of age-dependent progressive changes associated with aging, including skeletal muscle fibrosis, decreased muscle cell density, and intermuscular adipose tissue infiltration. While resistance training has been known to be effective in maintaining or increasing skeletal muscle mass, it is important to understand its effectiveness in addressing the different aspects in skeletal muscle health with aging. This review outlines methods for assessing various changes in skeletal muscle in older people and summarizes the evidence for the effectiveness of resistance training in improving skeletal muscle health. In terms of the effectiveness of resistance training for skeletal muscle mass, an alternative approach that is more feasible for older adults has been shown to be effective in addition to standard resistance training methods such as high-intensity and being performed to exhaustive state. On the other hand, scientific evidence on the effectiveness of resistance training in reducing inter- and/or intramuscular adipose tissue and increasing skeletal muscle cell mass remains to be accumulated. This review aims to identify these gaps in the research findings and highlights the need for individualized and multifaceted assessments and approaches to skeletal muscle in older people.