No abstract

The purpose of this study was to investigate the relationship between sprint performance and architectural characteristics of leg muscles in 26 female 100-m sprinters. Pennation angle and muscle thickness of the vastus lateralis (VL) and gastrocnemius medialis (GM) and lateralis (GL) muscles were measured by B-mode ultrasonography, and fascicle length was estimated. Sprinters had a significantly lower VL pennation angle, but GM and GL pennation angle was similar between sprinters and female control subjects (N = 22). There was no significant correlation between pennation angle and 100-m personal best performance. Sprinters had significantly greater absolute fascicle length in VL and GL than controls, which significantly correlated to 100-m best-record (r = -0.51 and r = -0.44, respectively). Relative fascicle length (VL and GL) were also significantly greater in sprinters than controls. However, there were no significant correlation between relative fascicle length and 100-m best-record (r = -0.36 and r = -0.29, respectively). No relationship was found between the sprint performance and fat-free mass (r = -0.26) or body mass index (r = -0.03). However, there was a significant correlation between percent (%) body fat and 100-m best-record (r = 0.62, p < 0.01). Adjusting the confounding effect of % fat, significant correlations were seen between relative fascicle length and 100-m best-record (VL; r = -0.39 and GL; r = -0.40). Absolute and relative fascicle length were similar in elite female sprinters compared with previous reported values for elite male sprinters (Kumagai et al., 2000). It was concluded that longer fascicle length is associated with greater sprinting performance in sprinters, but there is no gender differences in fascicle length for elite sprinters.

No abstract

It is generally believed that more muscle mass in the lower body reflects more muscular strength and power. If true, greater ground reaction forces may be facilitated from increasing muscle mass, which may result in higher maximal running speeds.One method to assess the potential contributions of body composition (i.e. muscle mass and fat mass) to sprint performance is to examine the associations between those variables within each sprinter across time. The present study examined the relationships between longitudinal changes in body composition and sprint performance. Twelve elite female sprinters (9 of whom participated in the Olympics and/or the World Championships) had total body muscle mass, leg muscle mass, and body fat estimated using ultrasound. For each participant, these measurements lasted at least 5 consecutive years and the longest was 10 consecutive years (average 7 ± 1.5 years). The best sprint time in each season was used for evaluating sprint performance. Our unadjusted model indicated that muscle mass, and body fat correlated favourably with sprint performance over time. After adjusting for the error variance attributable to body fat, the relationship muscle mass with sprint performance is largely eliminated. In the first adjusted model, the partial correlations were r = −0.20 for leg muscle mass and r = 0.46 for body fat. In the second, the partial correlations were r = −0.20 for total muscle mass and r = 0.50 for body fat. In conclusion, these findings may suggest that reducing fat mass may have a greater impact on sprint performance than increasing muscle mass.

Xanthophylls have been attracting attention as phytochemicals with antioxidant activity and various beneficial effects demonstrated by randomized clinical trials. Ripe red paprika has high xanthophyll content and is a valuable source of dietary xanthophylls. Our previous study revealed that paprika xanthophylls were detected in the plasma of healthy volunteers after oral administration and preferentially accumulated in erythrocytes, suggesting a potential beneficial effect on erythrocytes. The present study was performed to investigate the effect of paprika xanthophyll supplementation on respiratory parameters in athletes performing treadmill exercise. In a randomized, double-blind, placebo-controlled, parallel group study, 14 athletes were assigned to daily intake of a drink containing 9.0 mg of paprika xanthophylls or a placebo drink. Before and after the 4-week intervention period, blood samples were collected to measure plasma carotenoid levels. The athletes also performed treadmill exercise (12 km/hr for 20 min) before and after the 4-week intervention period, and respiratory parameters were analyzed. After 4 weeks, the paprika xanthophyll group had significantly higher levels of total plasma xanthophylls and total plasma carotenoids (p = 0.014 and 0.043, respectively) than the placebo group. V ・ O 2 , V ・ CO 2 , and V ・ E were significantly lower in the paprika xanthophyll group than the placebo group. These results suggest that paprika xanthophyll supplementation allowed athletes to perform exercise at a set intensity with lower oxygen uptake. Subjective fatigue after exercise was also significantly less severe in the paprika xanthophyll group.