Effect of Timing of Meal Intake after Squat Exercise Training on Bone Formation in the Rat Hindlimb.

Abstract

SummaryWe hypothesized that bone acquisition was affected by the timing of meal intake after resistance exercise training. This was based on the following previous results: 1) Nutrient intake right after exercise resulted in an increase in muscle mass and a decrease in abdominal fat mass as well as muscle protein synthesis when compared to the intake of a meal later after the exercise; and 2) body composition has been proposed to be a good predictor of bone mass. To substantiate our hypothesis, 20 male rats were assigned to either a group fed a meal right after squat exercise (R) or a group fed a meal 4h after the exercise (L). The 10-wk training program consisted of approximately 70% of one repetition maximum for each animal, 15 repetitions per set, 10 sets per day, 3d per week. As a result, hindlimb muscle mass in the R group was greater (p<0.05) than that in the L group and abdominal fat mass was less (p<0.01) in the R group as compared to the L group, regardless of there being no significant difference in body weight between the groups. Bone volume in the tibia (p<0.01) and femur (p<0.05) were both significantly greater in the R group than in the L group. Bone mineral content index (BMCI) and bone mineral density index (BMDI) in the tibia of the R group were significantly (p<0.05) greater than the corresponding values of the

"Effects of a Calcium-Deficient Diet and Resistance Exercise on Bone in Male and Female Rats of Different Biological Maturity"

“…These results suggest that exerciseinduced muscle hypertrophy is less likely to occur after maturation. Okano et al [7] suggested that exercise-induced muscle hypertrophy may be partially responsible for the increase in bone mineral density…”

“…Jumping exercise training increases bone mass to a greater extent than aerobic exercise training in growing rats [6]. It has been shown that the mineral density and amount in the tibia, as well as the weight of the femur, were higher in rats given food immediately after squat exercise than in rats given food 4 h later [7]. The effect of resistance exercise on increasing bone mass has also been observed in adult rats [8].…”

Effects of a calcium-deficient diet and resistance exercise on bone in male and female rats of different biological maturity

“…Okano et al [7] suggested that exercise-induced muscle hypertrophy may be partially responsible for the increase in bone mineral density and content observed in rats subjected to squat training. Fujii et al [16] reported that the exercise used in the present study increased muscle mass, increased aminolevulinic acid dehydratase activity (the rate-limiting enzyme in hemoglobin synthesis), and mitigated anemia in rats fed an iron-de cient diet.…”

“…Jumping exercise training increases bone mass to a greater extent than aerobic exercise training in growing rats [6]. It has been shown that the mineral density and amount in the tibia, as well as the weight of the femur, were higher in rats given food immediately after squat exercise than in rats given food 4 h later [7]. The effect of resistance exercise on increasing bone mass has also been observed in adult rats [8].…”