[Vitamin D deficiency study in railway drivers.].

Heart rhythm disturbances are significant pathology and one of the reason of sudden cardiac arrest. Locomotive crew drivers are at high risk for cardiovascular diseases, including heart rhythm disturbances. Multiple factors as a professional stress, frequent night shifts, lack of insolation, diet disbalance, low physical activity, exposure to vibration and noise, and an unfavorable industrial climate.

Alpha-actinin-3 (ACTN3) R577X polymorphism influences knee extensor peak power response to strength training in older men and women.

Background: The alpha-actinin-3 (ACTN3) R577X polymorphism has been associated with muscle power performance in cross-sectional studies.

Methods: We examined baseline knee extensor concentric peak power (PP) and PP change with approximately 10 weeks of unilateral knee extensor strength training (ST) using air-powered resistance machines in 71 older men (65 [standard deviation = 8] years) and 86 older women (64 [standard deviation = 9] years).

Results: At baseline in women, the XX genotype group had an absolute (same resistance) PP that was higher than the RR (p =.

Muscle-power quality: does sex or race affect movement velocity in older adults?

To determine sex and race differences in muscle power per unit of muscle contraction, knee-extensor muscle power normalized for knee-extensor muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50-85 years). Results revealed that women displayed a 38% faster peak movement velocity than men and African Americans had a 14% lower peak movement velocity than Whites of a similar age when expressed per unit of involved muscle (p < .001).

Effects of moderate-velocity strength training on peak muscle power and movement velocity: do women respond differently than men?

The effects of a 10-wk unilateral knee extension strength training (ST) program on peak power (PP) and peak movement velocity (PV), at given absolute (force load) and relative (same % of 1 repetition maximum) resistances (loads), were examined in 30 older men [64 yr (7 SD)] and 32 older women [62 yr (6 SD)]. PP increased significantly in both men and women at the same absolute (P < 0.001) and relative loads (P < 0.

Gender differences in skeletal muscle fatigability are related to contraction type and EMG spectral compression.

The purposes of this study were 1) to evaluate gender differences in back extensor endurance capacity during isometric and isotonic muscular contractions, 2) to determine the relation between absolute load and endurance time, and 3) to compare men [n = 10, age 22.4 +/- 0.69 (SE) yr] and women (n = 10, age 21.