Acute Effect Of Resistance Exercise Research Articles

Effect of resistance exercise on muscle steroid receptor protein content in strength-trained men and women

The purpose of this study was to examine the acute effect of resistance exercise (RE) on muscle androgen receptor (AR) and glucocorticoid receptor (GR) protein content. Fifteen resistance-trained men ( n = 8; 21 ± 1 years, 175.3 ± 6.7 cm, 90.8 ± 11.6 kg) and women ( n = 7; 24 ± 5 years, 164.6 ± 6.7 cm, 76.4 ± 15.6 kg) completed 6 sets of 10 repetitions of heavy squats. Blood samples were obtained before RE, after 3 and 6 sets of squats, and 5, 15, 30 and 70 min after RE. Muscle biopsies from the vastus lateralis were obtained before RE, and 10 min and 70 min after RE. Blood samples were analyzed for total and free testosterone concentrations and muscle samples were analyzed for AR and GR protein content. Circulating total testosterone increased significantly ( p ≤ 0.05) in men and free testosterone increased in men and women with exercise. AR was significantly reduced at 70 min post-exercise in men and at 10 min post-exercise in women compared to pre-exercise. There were no changes in GR following RE, but GR was significantly higher in women compared to men. These findings support a current paradigm for stabilization followed by a reduction and then a rebound in the acute AR response to RE but demonstrate that gender differences exist in the timeline of the AR response.

Increased Serum C-reactive Protein Concentrations After High Volume Resistance Exercise

C-reactive protein (CRP) is a marker of inflammation. The acute effect of resistance exercise on CRP is unclear. PURPOSE: To examine the effect of high volume resistance exercise on serum CRP concentrations. METHODS: Following University Ethical Advisory Committee approval, nine healthy males (aged 20.8 ± 0.05 years, height 1.81 ± 0.06 m, body mass 79.4 ± 11.5 kg, mean ± SD) completed two trials, exercise and control, one-week apart. The order of the trials was randomized and balanced. On the exercise trial participants reported to the laboratory at 09:00 h and performed five, 45-min bouts of weight lifting. Each bout consisted of 4 sets of 15 repetitions of 5 different exercises at 30–40% of one repetition maximum. There was a 15 min rest interval after the first two bouts, a 105 min lunch break after bout three and a 15 min rest interval between bouts four and five. Serum CRP concentrations were determined before exercise (09:00 h), immediately after the last bout of exercise (15:30 h) and on the day after exercise (08:00 h, 11:00 h and 14:00 h) using a high sensitivity CRP assay. On the control trial participants were inactive and serum CRP was measured at corresponding times to the exercise trial. RESULTS: Baseline serum CRP concentrations did not differ between trials (paired t-test, P=0.149) but the pattern of CRP response differed over time (repeated measures ANOVA, trial × time interaction, P=0.028) indicating elevated serum CRP post exercise (Table).Table: Serum CRP concentrations (mg-L-1) on a control and resistance exercise trial.CONCLUSION: High volume resistance exercise may lead to elevations in serum CRP concentrations. Further study is needed to determine if smaller volumes of resistance exercise produce a similar effect.