论田径运动员爆发力的训练

爆发力是多数田径运动员取得优异成绩的素质基础,本文采用文献法,从爆发力的生理学机制出发,对发展田径运动员爆发力的途径,爆发力训练方法,以及训练时的注意事项加以论述。提出了一些发展田径运动员爆发力的训练方法,以期能最大限度地挖掘运动员的爆发力潜能,达到提高运动成绩的目的。     

The Effect of the Rate of Muscle Contraction on the Force-Time Curve Parameters of Male and Female Subjects

Purpose: Suprapostural task performance (manual tracking) and postural control (sway and frequency) were examined as a function of attentional focus, age, and tracking difficulty. Given the performance benefits often found under external focus conditions, it was hypothesized that external focus instructions would promote superior tracking and reduced postural sway for both age groups, most notably as a function of tracking difficulty. Method: Postural sway, frequency of postural adjustments, and tracking accuracy under two levels of task difficulty were assessed for younger (M _age = 20.98 years) and older (M _age = 70.80 years) participants while they manually tracked a pursuit-rotor target. Participants received instructions to focus on either their actions (internal focus) or the effect of their actions (external focus). Results: Analyses revealed a beneficial effect of an external focus on suprapostural performance on the less-difficult (0.5 Hz) tracking task, and this performance was associated with a modest improvement in medial-lateral postural sway. Conclusion: The findings offer limited support for external focus-of-attention benefits under a mildly challenging tracking task. While older adults tend to adopt a conservative postural control strategy regardless of tracking task difficulty, external focus instructions on a suprapostural task promoted a modest, beneficial shift in postural control.     

Improving Active Range of Hip Flexion

Abstract

It is argued that previous studies of active flexibility have not achieved experimental control. An experiment then is described which achieved experimental control by using daily flexibility training over a 7-day period.

Forty-two female subjects were randomly assigned to one of six treatment groups or a control group. The six treatment groups received proprioceptive neuromuscular facilitation training for six consecutive days with isometric contraction periods of 0 sec, 3 sec, or 6 sec. Three of the treatment groups followed an active regime (concentric contraction of the agonists) and three a passive regime. All subjects were pretested for active flexibility on Day 1. They were also posttested after training on Day 6, and without training on Day 7. A two factor multivariate analysis of covariance with trend analysis on the period of isometric contraction factor indicated a significant positive linear trend for this factor, approximate F(2, 28) = 7.90, p < .002, together with a significant interaction between this linear trend and the active-passive regime factor, approximate F(2, 28) = 3.81, p < .034. Follow-up tests revealed that this interaction was due to larger gains in active flexibility being associated with longer periods of isometric contraction in the active groups, but not in the passive groups.