1. Introduction
muscle mass, muscle contraction, muscle hypertrophy
These authors contributed equally to this study.(1) The purpose of this study was to investigate the effect of whey protein supplementation under dietary control on improvements in muscle mass and function following resistance exercise training. (2) Thirty-two men were randomly assigned to a whey protein supplementation group taking whey protein isolate (PSG, The popularity of dietary supplements has steadily increased. Similarly, in the sports field, professional athletes and the general public who enjoy leisure activities consume a variety of health supplements. In particular, many people take protein supplements to improve muscle hypertrophy and function in combination with resistance exercise [Among dietary supplements, carbohydrate supplementation is the main source of energy for muscle contraction, whereas amino acid supplementation not only provides energy but also affects muscle protein synthesis and muscle recovery after resistance exercise [Many studies have investigated the effect of whey protein supplement intake on the increase in muscle mass and strength associated with resistance exercise. However, the results of these studies have been inconsistent. Several review papers [Most studies on the effects of whey protein supplementation on resistance exercise, even when the normal diet is controlled, have been conducted using food diaries or questionnaires reported by the participants on their diet records [In this study, we investigated the effect of whey protein supplementation on changes in muscle mass and isokinetic muscle function following resistance exercise while controlling the participants’ normal diet by providing three meals a day during the entire study period.