Medicine and science in sports and exercise
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Med Sci Sports Exerc · Jul 2016
Replacing Sedentary Time with Physical Activity in Relation to Mortality.
Data evaluating mortality benefit from replacing sedentary time with physical activity are sparse. We explored reallocating time spent in sedentary behavior to physical activity of different intensities in relation to mortality risk. ⋯ Replacing sedentary time with an equal amount of physical activity may protect against preterm mortality. Replacement of light physical activity with moderate to vigorous activity is also associated with protection from premature mortality.
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Med Sci Sports Exerc · Jun 2016
Randomized Controlled TrialEffect of Docosahexaenoic Acid on a Biomarker of Head Trauma in American Football.
American football athletes are exposed to subconcussive impacts over the course of the season resulting in elevations in serum neurofilament light (NFL), a biomarker of axonal injury. Docosahexaenoic acid (DHA) has been reported to reduce axonal trauma associated with traumatic brain injury in rodent models. However, the optimal dose in American football athletes is unknown. This study examined the effect of differing doses of DHA on serum NFL over the course of a season of American football. ⋯ Findings from this study, the first large-scale study examining potential prophylactic use of DHA in American football athletes, include identification of optimal dose of DHA, suggesting a neuroprotective effect of DHA supplementation.
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Med Sci Sports Exerc · Apr 2016
Displacing Sedentary Time: Association with Cardiovascular Disease Prevalence.
Isotemporal substitution analysis offers new insights for public health but has only recently been applied to sedentary behavior research. We aimed to quantify associations between the substitution of 10 min of sedentary behavior with 10 min of light physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) and the prevalence of cardiovascular disease (CVD). Age was also explored as a potential effect modifier. ⋯ Isotemporal substitution of sedentary time with LPA was associated with a trivial relative risk reduction for CVD, whereas the equivalent replacement with MVPA had a small beneficial relationship. With respect to CVD prevalence, MVPA might become decreasingly important in older individuals. Prospective studies are needed to investigate causality.
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Med Sci Sports Exerc · Nov 2015
Meta AnalysisOptimizing Cold Water Immersion for Exercise-Induced Hyperthermia: A Meta-analysis.
Cold water immersion (CWI) provides rapid cooling in events of exertional heat stroke. Optimal procedures for CWI in the field are not well established. This meta-analysis aimed to provide structured analysis of the effectiveness of CWI on the cooling rate in healthy adults subjected to exercise-induced hyperthermia. ⋯ An optimal procedure for yielding high cooling rates is proposed. Using prompt vigorous CWI should be encouraged for treating exercise-induced hyperthermia whenever possible, using cold water temperature (approximately 10°C) and maximizing body surface contact (whole-body immersion).
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Med Sci Sports Exerc · Nov 2015
Randomized Controlled TrialInhomogeneous Quadriceps Femoris Hypertrophy in Response to Strength and Power Training.
Previous studies have reported inhomogeneous changes in quadriceps femoris (QF) cross-sectional area (CSA) in response to strength training. It is assumed that these differential changes in muscle shape influence the muscle's functional capacity during high-force and high-power movements. The purpose of the current study was to compare intermuscular and intramuscular QF adaptations to high-load strength training and fast-speed power training. ⋯ These observed inhomogeneous changes in CSA may alter the thigh's moment of inertia and moment arms of muscle "compartments," and the influence of elastic component force transmission on the muscular force expression. Such selective hypertrophy is speculated to be biomechanically beneficial to high-force or high-power movements used in training.