Journal of strength and conditioning research
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J Strength Cond Res · Aug 2011
Heart rate and core temperature responses of elite pit crews during automobile races.
There is limited information regarding the physiological and psychological demands of the racing environment, and the subsequent effect on the performance of pit crew athletes. The purpose of this study was to evaluate heart rates (HRs) and core body temperatures (CTs) of pit crew athletes in the race environment. The HR and CT of pit crew athletes (n = 7) and control subjects were measured during 6 National Association for Stock Car Automobile Racing Sprint Cup races using ingestible sensors (HQ Inc, Palmetto, FL, USA). ⋯ Unexpectedly, the CTs of the pit crew athletes were not elevated in the race environment, despite high ambient temperatures and the extensive fire-protection equipment (e.g., helmet, suit, gloves) each pit crew athlete wore. The lack of CT change is possibly the result of the increased HR more efficiently shunting blood to the skin and dissipating heat as a consequence of the athletes' extensive training regimen and ensuing heat acclimation. Additionally, it is possible that psychological stress unique to several of the tracks provided an additive effect resulting in increased heart rates.
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J Strength Cond Res · Jul 2011
Relationship between peripheral muscle structure and function in patients with chronic obstructive pulmonary disease with different nutritional status.
The purpose of this study was to investigate the relationships between peripheral muscle structure (mass) and function (strength, endurance, and maximal aerobic capacity) in patients with chronic obstructive pulmonary disease (COPD) with different nutritional states. Thirty-nine patients (31 male) with moderate-severe COPD (63.5 ± 7.3 [SD] years) and 17 controls (14 male; 64.7 ± 5.5 [SD] years) underwent isokinetic (peak torque [PT]), isometric (isometric torque [IT]), and endurance strength (total work [TW]) measurements of the knee extensor muscles and a maximal cardiopulmonary exercise test to evaluate the maximal aerobic capacity (peak oxygen uptake [VO(2)] peak). Muscle mass (MM) was determined using dual-energy x-ray absorptiometry. ⋯ Muscle atrophy seems to be the main determinant of strength reduction among patients with moderate-severe COPD, whereas endurance reduction seems to be more related to imbalance between oxygen delivery and consumption than to the local muscle structure itself. Peripheral MM did not constitute a good predictor for maximal aerobic capacity in this population. The main practical application of this study is to point out a crucial role for the strategies able to ameliorate cardiorespiratory and muscular fitness in patients with COPD, even in those patients with preserved MM.
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J Strength Cond Res · May 2011
Personal best time and training volume, not anthropometry, is related to race performance in the 'Swiss Bike Masters' mountain bike ultramarathon.
We investigated in 73 male ultraendurance mountain bikers, with (mean and SD) age 39.1 (8.6) years, weight 74.4 (8.3) kg, height 1.78 (0.07) m, and a body mass index of 23.3 (1.9) kg·m⁻², whether variables of anthropometry, training, or prerace experience were associated with race time using bi and multivariate analysis. Our investigation was conducted at the "Swiss Bike Masters," which covers a distance of 120 km and an altitude of 5,000 m. In the bivariate analysis, body mass index (r = 0.29), circumference of upper arm (r = 0.28), sum of upper body skinfolds (r = 0.38), sum of lower body skinfolds (r = 0.25), sum of 8 skinfolds (r = 0.36), percent body fat (r = 0.41), total cycling kilometers per year (r = -0.47), yearly volume in both mountain bike (r = -0.33) and road cycling (r = -0.52), number of training units per week (r = -0.48), distance per unit in road cycling (r = -0.33), average speed during training in road cycling (r = -0.33), and personal best time in the "Swiss Bike Masters"(r = 0.67) were related to race time. ⋯ When the personal best time was the dependent variable in a separate regression model, total yearly cycling kilometers (p = 0.002) remained the single predictor variable. We concluded that finishing a particular mountain bike ultramarathon does not seem to require a special anthropometry but rather a specific skill and experience for this selective kind of race coupled with a high training volume. For practical use, we concluded that successful athletes in a mountain bike ultramarathon, in a special environment and using sophisticated equipment, need prerace experience coupled with high training volume, rather than any special anthropometry.
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J Strength Cond Res · May 2011
Comparative StudyAre the perceptual and decision-making components of agility trainable? A preliminary investigation.
Agility is an open motor skill; requiring change of direction speed (CODS) and perceptual and decision-making ability. The aim of this study was to determine whether the perceptual and decision-making component of agility can be trained. Fifteen rugby league players were tested on a sport-specific reactive agility test (RAT) and a CODS test. ⋯ All other comparisons were not. Results from this study suggest that the perceptual and decision-making components of agility are trainable. Coaches should incorporate some open motor skills training in their programs when training agility.
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J Strength Cond Res · Apr 2011
Randomized Controlled TrialResponse time to stimuli in division I soccer players.
The purpose of this investigation was to examine the effect of auditory stimuli (AS) and visual stimuli (VS) on sprint time, sprint speed, and reaction time in National Collegiate Athletic Association Division I male soccer players. Fifteen healthy subjects (mean age 22.1 ± 1.6 years) volunteered for the study. This experiment was conducted on a regulation soccer field, using a wireless timing system. ⋯ Sprint speed (distance covered) was greater in VS compared to AS (5.3 ± 0.21 m · s vs. 5.1 ± 0.19 m · s, p < 0.001), and reaction time was reduced in VS compared to AS (0.53 ± 0.048 seconds vs. 0.61 ± 0.044 seconds, p = 0.001). These data show that VS rather than AS improve sprint response times in collegiate male soccer athletes. The data suggest that performance on the field may be improved if coaches and players strategize to integrate visual cues (e.g., gestures and signals) during practices and games.