Access to exercise and its relation to cardiovascular health and gene expression in laboratory animals.

The interaction between genes and environment can influence cardiovascular disease (CVD). This 16 month study investigated if genes associated with cardiovascular (CV) regulation were expressed differently in animals having: 1) no access to physical activity or exercise (SED), 2) access to hour-long, twice weekly activity (PA), and 3) access every-other-day to a running wheel (EX). Out of 31,000 genes, a CV subset comprising 44 genes was investigated. Ten genes from this subset were expressed differently in EX compared with SED, and 34 genes were expressed differently in PA compared with SED (p<0.05). Total cholesterol (70+/-8 vs. 101+/-9 mg dl(-1)), triglycerides (104+/-8 vs. 127+/-4 mg dl(-1)), resting systolic blood pressure (130+/-3 vs. 141+/-3 mmHg), mean arterial pressure (110+/-2 vs. 120+/-2 mmHg) and heart rate (380+/-6 vs. 405+/-9 beats min(-1)) were lower in EX compared with SED (p<0.05), but intracellular adhesion molecule levels did not differ among groups. Mean gene expressions for Gja1, Fdft1, Edn1, Cd36, and Hmgb2 differed in animals according to access to physical activity. These genes play roles in heart rate, cholesterol biosynthesis, blood pressure, cell adhesion, and transcription and neurogenesis regulation, respectively. In conclusion, a total of 44 CV genes were expressed differently in SED compared to PA and EX; and SED showed more physiological evidence of CVD.

Use of an overhead goal alters vertical jump performance and biomechanics.

This study examined whether an extrinsic motivator, such as an overhead goal, during a plyometric jump may alter movement biomechanics. Our purpose was to examine the effects of an overhead goal on vertical jump height and lower-extremity biomechanics during a drop vertical jump and to compare the effects on female (N = 18) versus male (N = 17) athletes. Drop vertical jump was performed both with and without the use of an overhead goal. Greater vertical jump height (p = 0.002) and maximum takeoff external knee flexion (quadriceps) moment (p = 0.04) were attained with the overhead goal condition versus no overhead goal. Men had significantly greater vertical jump height (p < 0.001), maximum takeoff vertical force (p = 0.009), and maximum takeoff hip extensor moment (p = 0.02) compared with women. A significant gender x overhead goal interaction was found for stance time (p = 0.02) and maximum ankle (p = 0.04) and knee flexion angles (p = 0.04), with shorter stance times and lower angles in men during overhead goal time. These results indicate that overhead goals may be incorporated during training and testing protocols to alter lower-extremity biomechanics and can increase performance.

Exercise improves biomarkers of health and stress in animals fed ad libitum.

Voluntary and forced exercise decrease morbidity and mortality in laboratory animals. Caloric restriction has similar effects on health and unique benefits on life span. Nonetheless, in most experiments, animals do not have access to physical activity and are fed ad libitum (AL). We hypothesized that with regular access to either unlimited running wheel exercise (EX) or limited physical activity (PA), key biomarkers of health would be enhanced enough to counter some consequences of a sedentary AL lifestyle. This 16-month study compared body weight, tumor number and size, tissue lesions, oxidative stress, and reactive stress in (1) sedentary animals with no access to physical activity (SED); (2) animals with access to hour-long, twice weekly activity in a large box (PA); and (3) animals with access every other day to a running wheel (EX). At the end of the study, EX body weight was 8-9% lower than PA and SED. In addition, EX had no kidney lesions versus 50% in PA and SED, and had smaller tumor size (10+/-2 vs. 14+/-4 and 30+/-4 mm). Exhaustive exercise lowered glutathione/oxidized glutathione ratio in EX and PA, but in SED, the ratio was depressed even in resting animals. In all treatments, prolactin (PRL) levels were lower in resting animals than in acutely exercised animals. In conclusion, EX had the most favorable health biomarkers while SED had the least. PA did not confer gross health benefits different than the SED group, but was biochemically more similar to EX animals.