Basal concentrations and acute responses of serum hormones andstrength development during heavy resistance training in middle-aged andelderly men and women

Open Access
Publisher Website
Google Scholar
Abstract
Effects of 6 months of heavy resistance training combined with explosiveexercises on both basal concentrations and acute responses of total andfree testosterone, growth hormone (GH), dehydroepiandrosterone (DHEA),dehydroepiandrosterone sulfate (DHEAS), cortisol and sex hormone-bindingglobulin (SHBG), as well as voluntary neural activation and maximalstrength of knee extensors were examined in 10 middle-aged men (M40; 42 +/-2 years), 11 middle-aged women (W40; 39 +/- 3 years), 11 elderly men (M70;72 +/- 3 years), and in 10 elderly women (W70; 67 +/- 3 years). The maximalintegrated electromyographic (iEMG) and 1 repetition maximum (RM)knee-extension values remained unaltered in all groups during a 1-monthcontrol period with no strength training. During the 6-month training the1RM values increased in M40 by 27 +/- 9% (p < .001), in M70 by 16 +/- 6%(p < .001), in W40 by 28 +/- 11% (p < .001), and in W70 by 24 +/- 10%(p < .001). The iEMGs of the vastus lateralis and medialis musclesincreased(p < .05-.001) in M40, M70, W40, and W70. No systematic changesoccurred during the experimental period in the mean concentrations of serumtotal and free testosterone, DHEA, DHEAS, GH, cortisol, or SHBG. However,the mean levels of individual serum free testosterone in W70 and serumtestosterone in the total group of women correlated with the individualchanges recorded in strength during the training (r = .55,p <.05; and r= .43,p <.05). The single exercise session both before and after thetraining resulted in significant responses in serum total and freetestosterone concentrations in both male groups (p <.05-.01), but not inthe female groups, as well as in serum GH levels in all groups (p<.05-.01) except W70 (ns). In summary, the present strength training ledto great increases in maximal strength not only in middle-aged but also inelderly men and women. The strength gains were accompanied by largeincreases in the maximal voluntary activation of the trained muscles. Noneof the groups showed systematic changes in the mean serum concentrations ofhormones examined. However, a low level of testosterone, especially inolder women, may be a limiting factor in strength development andtestosterone could mediate interactions with the nervous systemcontributing to strength development. The physiological significance of thelack of acute responsiveness of serum GH to heavy resistance exercise inolder women for their trainability during prolonged strength trainingrequires further examination.

This publication has 0 references indexed in Scilit: