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  • Author: Joel M. Stager x
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Andrew C. Cornett and Joel M. Stager

It has been hypothesized that large differences in maximal performance can arise between various geopolitical regions solely on the basis of differing numbers of participants in the target activity. While there is evidence in support of this hypothesis for a measure of intellectual performance, the same relationship has not been examined for a measure of physical performance.

Purpose:

To determine whether the number of participants is a predictor of the best athletic performance in a region.

Methods:

The 2005–2010 USA Swimming Age Group Detail reports were used to determine the number of competitive swimmers participating in each age group for the 59 local swimming communities in the United States. The USA Swimming performance database provided 50-yd-freestyle times in each community for boys and girls for each age (6–19 y). Simple linear regression was used to examine the relationship between the outcome variable (fastest time) and the predictor variable (log of the number of swimmers) for each combination of age, sex, and calendar year.

Results:

The log of the number of swimmers in a region was a significant predictor of the best performance in that region for all 168 combinations of age, sex, and calendar year (P < .05) and explained, on average, 41%, and as much as 62%, of the variance in the fastest time.

Conclusions:

These findings have important implications for the development of regional sport strategic policy. Increasing the number of participants in the target activity appears a viable strategy for improving regional performance.

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Abigail S.L. Stickford, Robert F. Chapman, Jeanne D. Johnston and Joel M. Stager

The efficacy of and mechanisms behind the widespread use of lower-leg compression as an ergogenic aid to improve running performance are unknown. The purpose of this study was to examine whether wearing graduated lower-leg compression sleeves during exercise evokes changes in running economy (RE), perhaps due to altered gait mechanics. Sixteen highly trained male distance runners completed 2 separate RE tests during a single laboratory session, including a randomized-treatment trial of graduated calf-compression sleeves (CS; 15–20 mm Hg) and a control trial (CON) without compression sleeves. RE was determined by measuring oxygen consumption at 3 constant submaximal speeds of 233, 268, and 300 m/min on a treadmill. Running mechanics were measured during the last 30 s of each 4-min stage of the RE test via wireless triaxial 10-g accelerometer devices attached to the top of each shoe. Ground-contact time, swing time, step frequency, and step length were determined from accelerometric output corresponding to foot-strike and toe-off events. Gait variability was calculated as the standard deviation of a given gait variable for an individual during the last 30 s of each stage. There were no differences in VO2 or kinematic variables between CON and CS trials at any of the speeds. Wearing lower-leg compression does not alter the energetics of running at submaximal speeds through changes in running mechanics or other means. However, it appears that the individual response to wearing lower-leg compression varies greatly and warrants further examination.

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Jonathon L. Stickford, Timothy D. Mickleborough, Alyce D. Fly and Joel M. Stager

Purpose:

Conjugated linoleic acid (CLA) has been reported to modify the inflammatory response associated with allergic airway disease, primarily in animal models. To extend these observations to humans, the effect of short-term CLA supplementation on the severity of exercise-induced bronchoconstriction (EIB) was investigated in asthmatics.

Methods:

Six subjects with physician-diagnosed asthma and EIB began the study on their usual diet, to which was added 4.8 g CLA/d for 8 wk. Pulmonary-function tests were administered before and after eucapnic voluntary hyperventilation (EVH) challenge at the commencement (Week 0) and conclusion of the treatment period (Week 8). Pre- and 90 min post-EVH challenge, urine was assayed for the presence of cysteinyl leukotrienes (LT) C4−E4 and 9α,11β-prostaglandin (PG) F2.

Results:

Pre- to post- EVH forced expiratory volume in 1 s (FEV1) did not significantly differ (p > .05) from Week 8 to Week 0. The pre- to post-EVH decline in FEV1 at Week 8 (–29.6% ± 6.6%) was not significantly different (p > .05) from that at Week 0 (–32.0% ± 5.5%). Area under the curve of FEV1 plotted against time from zero to 60 min (AUC0–60) was unaltered at Week 8 (–931% ± 350% change per minute) compared with Week 0 (−1,090% ± 270% change per minute). CLA supplementation did not alter forced midexpiratory flow, forced vital capacity (FVC), or FEV1/FVC. In addition, post-EVH urinary LTC4–E4 and 9α,11β-PGF2 were unchanged after CLA supplementation.

Conclusion:

Daily supplementation of 4.8 g CLA for 8 wk does not attenuate airway inflammation or hyperpnea-induced bronchoconstriction in asthmatic individuals.

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Kosuke Kojima, Christopher L. Brammer, Tyler D. Sossong, Takashi Abe and Joel M. Stager

Purpose: The purpose of this study is to compare the efficacy of resisted sprint swim training with that of nonresisted sprint swim training on 50-m freestyle competition time (Vmax50) in age-group swimmers. Methods: Twenty-four age-group swimmers (age 10.6–14.9 y) were divided into resisted or nonresisted sprint swim training groups and completed a sprint swim training intervention 2 times per week for 10 weeks. Repeated 10-m sprints with progressively increasing resistance were used to determine measures of swim power. Skeletal muscle mass was estimated using B-mode ultrasound. Maturity status was estimated using predicted adult height (%Htadult) and maturity offset. Results: A 2-way repeated-measures analysis of variance revealed no group × time interaction for measured variables. Vmax50 was correlated with skeletal muscle mass and swim power variables, but no significant relationship was found between relative changes in these variables. Estimated maturity status (%Htadult) appeared to be associated with initial measures of swim power and performance variables. Conclusions: Ten weeks of resisted sprint swim training was not any more effective than nonresisted sprint swim training at improving sprint swim performance in age-group swimmers.

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Jason R. Karp, Jeanne D. Johnston, Sandra Tecklenburg, Timothy D. Mickleborough, Alyce D. Fly and Joel M. Stager

Nine male, endurance-trained cyclists performed an interval workout followed by 4 h of recovery, and a subsequent endurance trial to exhaustion at 70% VO2max, on three separate days. Immediately following the first exercise bout and 2 h of recovery, subjects drank isovolumic amounts of chocolate milk, fluid replacement drink (FR), or carbohydrate replacement drink (CR), in a single-blind, randomized design. Carbohydrate content was equivalent for chocolate milk and CR. Time to exhaustion (TTE), average heart rate (HR), rating of perceived exertion (RPE), and total work (WT) for the endurance exercise were compared between trials. TTE and WT were significantly greater for chocolate milk and FR trials compared to CR trial. The results of this study suggest that chocolate milk is an effective recovery aid between two exhausting exercise bouts.