Effects of upper-body, lower-body, or combined resistance training on the ratio of follistatin and myostatin in middle-aged men

Abstract

Purpose: Due to the mechanistic role of myostatin and follistatin in modulating muscle mass, shifts in the 3 follistatin to myostatin ratio (F: M) may help explain changes in muscular size in response to resistance training 4 (RT). The present study examined whether differential responses in follistatin and myostatin occur based on the 5 amount of active musculature in a RT program in middle-aged men. 6 Methods: Forty middle-aged men (age= 46.5±3.1 years) were randomly assigned to one of 4 groups, upper-body 7 RT (UB; n=10), lower-body RT (LB; n=10), combined RT (UB+LB; n=10) or control (C; n=10). The training 8 protocol consisted of 3 exercise sessions per week for 8 weeks. Blood samples were obtained at baseline and 48 9 hours after the final session of the training program. 10 Results: Muscle mass significantly increased (p˂0.05) following UB= 0.76 ± 0.46 kg, LB= 0.90 ± 0.29 kg, 11 UB+LB= 1.38 ± 0.70 kg, compared to no changes after control. Serum follistatin increased in the LB= 0.24 ± 0.06 12 ng.mL-1 , UB= 0.27 ± 0.17 ng.mL-1 , UB+LB= 0.50 ± 0.18 ng.mL-1 , while serum myostatin decreased in the LB=-13 0.11 ± 0.08 ng.mL-1 and UB+LB=-0.34 ± 0.23 ng.mL-1 , but not UB= 0.07 ± 0.16 ng.mL-1. Further, change in 14 concentration following training was larger between UB+LB and either LB or UB alone for both follistatin and 15 myostatin. 16 Conclusions: Both UB and LB increase muscle mass and alter the F: M ratio, however the change in these 17 endocrine markers is approximately twice as large if UB and LB is combined. The endocrine response to RT of 18 myostatin and follistatin may depend on the volume of muscle mass activated during training.

Comparison of whole egg v. egg white ingestion during 12 weeks of resistance training on skeletal muscle regulatory markers in resistance-trained men

“…An a priori sample size calculation was conducted using the G*Power analysis software (22) . Our rationale for sample size was based on previous data (1,23,24) . Based on an α value of 0•05 and a power (1 -β) value of 0•85, the analysis revealed that a total sample size of at least thirty participants (n 15 per group) was needed to have sufficient power to detect significant changes in MSTN and FLST concentrations.…”

“…The participant's stature was measured with a stadiometer (Race Industrialization) to the nearest 0•1 cm. BMI, fat mass (FM) and SMM were evaluated using a multi-frequency bioelectrical impedance device (Inbody 720) (1) . Prior to the measurement, the participant's palms and soles were cleaned with an electrolyte tissue.…”

“…The 1RM value was also used to determine the relative training intensity of the RT programme (19) . Participants were instructed to refrain from caffeinated drinks for 12 h and food intake for 2 h prior to the testing session; however, water consumption was allowed (1) .…”

“…To minimise dietary variability, participants submitted 3-d (2 weekdays and 1 weekend) food records at baseline and at 12 weeks of the assigned intervention. Each item of food was individually entered into Diet Analysis Plus, version 10 (Cengage), and total energy consumption and the amount of energy derived from proteins, fats and carbohydrates were assessed (1) .…”

“…Resistance training (RT) is acknowledged as an effective modality for enhancing muscular strength and hypertrophy (1) . The mechanical tension and metabolic stress imposed on skeletal muscle via RT modalities, when combined with proper nutritional factors, can result in a net anabolic response in myofibrillar protein metabolism, leading to myofiber hypertrophy and muscular growth over time (2) .…”