Effects Of High-velocity Resistance Training On Lean-tissue Mass And Myostatin Among Community-dwelling Older Adults

Abstract

Among older adults, mobility disability is prominent, affecting 20% of community-dwelling adults over 70 years. This number is expected to rise over the next 35 years as the number of older adults is expected to more than double in size. Factors affecting mobility disability include muscular strength, muscular power, and lean-tissue mass, which all decrease throughout the lifespan. In addition, myostatin, a potent inhibitor of muscle growth, is inversely correlated with reductions in mobility disability variables. However, exercise is the only known treatment for mobility disability and works by improving muscular strength, power, and lean tissue mass, in addition to decreasing myostatin expression. Yet, the optimal exercise intervention has yet to be determined for this age group. PURPOSE: Therefore, the purpose of this study was to examine serum myostatin, muscular strength, muscular power, and lean-tissue mass changes following a 20-week, high-velocity resistance training (HVRT) intervention among community-dwelling older adults. METHODS: Forty-three older adults (77.2 + 6.2 years) were randomly assigned to high-velocity exercise at 70% of their one repetition maximum (1-RM) or a control group. The control group participated in the same exercises; however, only used their body weight as resistance. All participants exercised two days per week. RESULTS: There were no significant group by time interactions for any variable at baseline or after 20-weeks of HVRT. There was a trend for significant interaction in total muscular strength (p = .056); the HVRT group increased strength by 28.4% and the control group by 18.2%. HVRT significantly increased muscular power (23.2%, p = <.001) in both groups; however, there was no statistically significant increase in lean-tissue mass (+1.2%, p = .21) for either group. Serum myostatin had a statistically insignificant reduction after the intervention (-9.0%, p = .08). CONCLUSIONS: HVRT, with or without an external load, is beneficial for increasing muscular strength and power, and decreasing serum myostatin among older adults. Therefore, HVRT presents as an optimal training modality for minimizing mobility disability with age; however, the intensity of the activity should be studied further.