Search

Oxidative stress seems to be involved in the pathogenesis of Parkinson disease (PD). Exercise training can increase endogenous antioxidant protection and decrease the production of reactive oxygen and nitrogen species. PURPOSE:: To investigate the effect of exercise training on oxidative status in persons with PD. METHODS:: Sixteen subjects with PD were match-randomly assigned to resistance exercise (n = 8) or a no-exercise control group (n = 8) on the basis of disease stage (Hoehn and Yahr stages I and II) and sex. Supervised exercise was performed twice weekly for 8 wk, consisting of three sets each of the leg press, leg curl, and calf press. Resting blood samples were taken from subjects before and after the intervention and assayed for markers of oxidative stress [malondialdehyde (MDA) and hydrogen peroxide (H2O2)] and antioxidant capacity (superoxide dismutase, catalase, glutathione peroxidase, and trolox-equivalent antioxidant capacity). RESULTS:: The exercise program was well-tolerated and associated with modest trends toward decreased oxidative stress and increased antioxidant capacity. The two biomarkers of oxidative stress were decreased after exercise training [MDA (15%) and H2O2 (16%)]. With these changes, a postintervention difference was apparent between the resistance exercise training and control groups for H2O2 (P = 0.007), with a trend for difference noted for MDA (P = 0.06). The mean increases in superoxide dismutase (9%) and glutathione peroxidase (15%) noted in the exercise training group were not statistically significant (P > 0.05). CONCLUSIONS:: Short-term resistance training may be associated with reduced oxidative stress in subjects with PD. Future studies with larger samples, inclusive of a higher volume of resistance exercise, are needed to extend these findings. [ABSTRACT FROM AUTHOR]

To determine the effects of 12 weeks of resistance exercise with MYOVIVE and/or colostrum supplementation, 19 male and female recreationally weight-trained subjects (X +/- SE; age = 28.3 +/- 6.9 yrs; hgt = 68.2 +/- 3.8 cm) were divided into MYOVIVE + colostrum (n = 4), MYOVIVE + casein & whey (n = 4), colostrum + casein & whey (n = 6), and casein & whey (n = 5) groups. All groups similarly increased (p < .05) 1 repetition maximum (RM) leg press (kg; pre = 158.6 +/- 12.8, post = 189.3 +/- 11.3), body mass (kg; pre = 79.0 +/- 3.2, post = 80.7 +/- 3.8), and lean body mass (kg; pre = 60.1 +/- 3.1, post = 62.2 +/- 2.8). Increases were observed for peak force (N; all loads), peak velocity (m x s[-1]; 70% & 40% 1 RM), and peak power (W; 70% & 40% 1 RM) for all groups for the leg press exercise, with no differences between groups. When performance data were adjusted for body mass, lean body mass, lower body lean mass as determined by DEXA, or % change, no group differences were observed. Relative (%) fiber type content, cross-sectional areas (microm[2]), % fiber type areas, or % myosin heavy chain expression did not change for any group. These data suggest that MYOVIVE and colostrum supplementation have no greater effect on cellular and performance adaptations when compared to casein and whey protein. [ABSTRACT FROM AUTHOR]

Computerized agility training (CAT) products are frequently suggested to improve agility. However, these claims often are made without unbiased scientific support. Therefore, the purpose of this study was (a) to determine the reliability and effectiveness of a 4-week CAT training program on foot speed (FS) and choice reaction (REACT), and (b) to assess whether training on the CAT would facilitate the improvement of a separate change-of-direction (COD) test in non-agility-trained, but active, men and women. Twenty-three participants (15 men, 8 women) pre- and posttested on FS, REACT, and COD drills. Eleven of those participants (7 men, 4 women) engaged in 4 weeks of training on the FS and REACT drills (EX). The remaining 12 (8 men, 4 women) did not participate in the training and served as controls (CON). Coefficients of variation indicate strong precision for FS (6.9%) and REACT (2.6%). Test-retest reliability, as analyzed by intraclass correlations (ICC), were high for both FS and REACT (0.89). Significant test-by-group interactions were observed for all three tests: FS (p = 0.004), REACT (p = 0.011), and COD (p = 0.049). Post hoc analysis indicated that EX increased foot contacts for the FS drill (p = 0.006), whereas REACT and COD demonstrated decreases in time to completion (p = 0.013 and 0.038, respectively). The CON group did not improve on any of the tests. This study indicates that the chosen CAT is an accurate and reliable tool for measuring foot speed and reaction time. These data justify the use of this CAT in analyzing foot speed and reaction time. Altogether, 4 weeks of foot speed and reaction training on the chosen CAT produced improvements in overall agility in non-agility-trained, but active, men and women. These data warrant the integration of such a device into the training program of untrained athletes attempting to improve agility. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the influence of myosin heavy chain (MHC) isoform composition and training status on the mechanomyographic (MMG) amplitude versus isometric torque relationship for the vastus lateralis. Five resistance-trained (mean +/- SD age = 23.2 +/- 3.7 years), 5 aerobically trained (mean +/- SD age = 32.6 +/- 5.2 years), and 5 sedentary (mean +/- SD age = 23.4 +/- 4.1 years) men performed isometric muscle actions of the leg extensors in 20% increments from 20% to 100% of the maximum voluntary contraction. Biopsies from the vastus lateralis revealed that the MHC composition for the resistance-trained subjects was 59.0 +/- 4.2% Type IIa, 0.1 +/- 0.1% Type IIx, and 40.9 +/- 4.3% Type I. The aerobically-trained subjects had 27.4 +/- 7.8% Type IIa, 0.0 +/- 0.0% Type IIx, and 72.6 +/- 7.8% Type I MHC. The sedentary subjects had 42.1 +/- 7.8% Type IIa, 17.8 +/- 6.4% Type IIx, and 40.1 +/- 10.9% Type I MHC. There were no consistent patterns of responses for the resistance-trained, aerobically trained, or sedentary subjects for MMG amplitude versus torque. Thus, differences in MHC isoform composition and training status did not explain the unique torque-related patterns for MMG amplitude. [ABSTRACT FROM AUTHOR]