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We have previously reported on the possibility that light resistance exercise performed with a high plasma amino acid concentration resulting from the ingestion of a high-protein snack (HPS; 15 g protein, 18 g sugar) 3 h after a basal meal promotes the utilization of amino acids in peripheral tissues such as muscle in both rats and humans. In the present study, we further examined the effectiveness of a daily routine involving ingestion of HPS 3 h after a basal meal and subsequent light resistance exercise (dumbbell exercise) in increasing the mass and strength of human muscle. Ten young adult males were subject to the following 3 conditions for 5 wk each, with sufficient recovery period between each condition: (1) Snack-Exercise (SE), (2) Snack-Sedentary (SS), and (3) No snack-Exercise (NE). The SE group showed a significant increase in lean body mass and total cross-sectional area (CSA) of the right forearm muscles along with a significant decrease in body fat mass. The SS group showed no change in body composition. Furthermore, the SE group showed significant increase in grip strength and isometric knee extensor muscle strength, while the SS group showed no increase in muscle strength. The NE group showed significant increase in grip strength. In conclusion, daily routine ingestion of HPS 3 h after a basal meal and subsequent light resistance exercise is effective in increasing the mass and strength of human muscle.

The study investigated exercise patterns resulting in the more efficient promotion of amino acid utilization. High-protein snacks (HPS; 15 g protein, 18 g sugar) were ingested by 8 young adult subjects 3 h after the basal meal ingestion. Sixty minutes after the HPS ingestion, the subjects performed arm flex/extend exercises for 15 min. The difference between 2 exercise patterns was compared. Pattern 1: High-number long-interval (HL) arm flex/extend (3+3 s) exercise; the HL group performed 9 sets of 15 exercises with a 10 s interval between sets. Pattern 2: Low-number short-interval (LS) arm flex/extend (3+3 s) exercise; the LS group performed 27 sets of 5 exercises with a 3-4 s interval between sets (135 exercises during 15 min, respectively). The plasma branched-chain amino acid (BCAA) concentrations were measured before the HPS ingestion, before the exercise, and 60 and 90 min after the HPS ingestion. The plasma BCAA concentrations increased significantly after the HPS ingestion. In the HL group, BCAA concentration increased consistently during the period and 60 to 90 min after the HPS ingestion. During the same period in the LS group the BCAA concentration stopped increasing. After HPS ingestion, a significantly greater suppressive effect on plasma BCAA concentration was seen in the LS group compared to the HL group. Results confirmed that the intermittent blood volume fluctuation in muscle tissue during the exercise pattern performed by the LS group had an effect on the utilization of nutritional components (BCAA, glucose) from the blood, and showed the possibility that the group where the blood volume in the muscle tissue increased/lowered with higher frequency was a more effective exercise pattern for nutrient utilization.

We have previously reported the preventive effects of light resistance exercise (voluntary tower climbing exercise) after ingestion of a high-protein snack (HPS) on muscle loss in glucocorticoid-injected rats. However, such studies have not been performed in humans. In this cross-over study, we examined the effect of light resistance exercise after ingestion of HPS on plasma branched-chain amino acid (BCAA) concentrations in humans. Seven healthy young adult females (aged 22.1+/-1.2 y) participated in this study. They were assigned to either an exercise group or a control group. Seven days after the first experiment, they were crossed over to the opposite intervention. The subjects ingested HPS (15 g protein, 18 g sugar) 3 h after breakfast (basal meal). The plasma BCAA concentrations increased at 30 min after HPS ingestion. The subjects in the exercise group performed light resistance exercise (15 min dumbbell exercise using 300 g brown-rice-filled fabric dumbbells) when the plasma BCAA concentrations were increased (60 min after the snack ingestion). The control group maintained a resting position during the experiment. Changes in the plasma BCAA concentrations between 60 and 90 min after HPS ingestion increased continuously in the control group (+27 micromol/L) but decreased in the exercise group (-37 micromol/L). Therefore, light resistance exercise after HPS ingestion may be effective for utilization of plasma BCAA in humans.