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  • Author: James C. Brown x
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John McDaniel, N. Scott Behjani, Steven J. Elmer, Nicholas A.T. Brown and James C. Martin

Previous authors have reported power-pedaling rate relationships for maximal cycling. However, the joint-specific power-pedaling rate relationships that contribute to pedal power have not been reported. We determined absolute and relative contributions of joint-specific powers to pedal power across a range of pedaling rates during maximal cycling. Ten cyclists performed maximal 3 s cycling trials at 60, 90, 120, 150, and 180 rpm. Joint-specific powers were averaged over complete pedal cycles, and extension and flexion actions. Effects of pedaling rate on relative joint-specific power, velocity, and excursion were assessed with regression analyses and repeated-measures ANOVA. Relative ankle plantar flexion power (25 to 8%; P = .01; R 2 = .90) decreased with increasing pedaling rate, whereas relative hip extension power (41 to 59%; P < .01; R 2 = .92) and knee flexion power (34 to 49%; P < .01; R 2 = .94) increased with increasing pedaling rate. Knee extension powers did not differ across pedaling rates. Ankle joint angular excursion decreased with increasing pedaling rate (48 to 20 deg) whereas hip joint excursion increased (42 to 48 deg). These results demonstrate that the often-reported quadratic power-pedaling rate relationship arises from combined effects of dissimilar joint-specific power-pedaling rate relationships. These dissimilar relationships are likely influenced by musculoskeletal constraints (ie, muscle architecture, morphology) and/or motor control strategies.

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Michael C. Geraci Jr., Walter Brown and James R. Velasquez

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James C. Brown, Caron-Jayne Miller, Michael Posthumus, Martin P. Schwellnus and Malcolm Collins

Purpose:

Endurance running performance is a multifactorial phenotype that is strongly associated with running economy. Sit and reach range of motion (SR ROM) is negatively associated with running economy, suggesting that reduced SR ROM is advantageous for endurance running performance. The COL5A1 gene has been associated with both endurance running performance and SR ROM in separate cohorts. The aim of this study was to investigate whether COL5A1 is associated with ultra-marathon running performance and whether this relationship could be partly explained by prerace SR ROM.

Methods:

Seventy-two runners (52 male, 20 female) were recruited from the 56 km Two Oceans ultra-marathon and were assessed for prerace SR ROM. The cohort was genotyped for the COL5A1 BsfUI restriction fragment length polymorphism, and race times were collected after the event.

Results:

Participants with a TT genotype (341 ± 41 min, N = 21) completed the 56 km Two Oceans ultra-marathon significantly (P = 0.014) faster than participants with TC and CC genotypes (365 ± 39 min, N = 50). The COL5A1 genotype and age accounted for 19% of performance variance. When the cohort was divided into performance and flexibility quadrants, the T allele was significantly (P = 0.044) over-represented within the fast and inflexible quadrant.

Conclusion:

The COL5A1 genotype was found to be significantly associated with performance in a 56 km ultra-endurance run. This study confirms previous findings and it furthers our understanding of the relationships among ROM, COL5A1, and endurance running performance. We continue to speculate that the COL5A1 gene alters muscle-tendon stiffness.

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James C. Martin, Steven J. Elmer, Robert D. Horscroft, Nicholas A.T. Brown and Barry B. Shultz

The purpose of this study was to develop and evaluate an alternative method for determining the position of the anterior superior iliac spine (ASIS) during cycling. The approach used in this study employed an instrumented spatial linkage (ISL) system to determine the position of the ASIS in the parasagittal plane. A two-segment ISL constructed using aluminum segments, bearings, and digital encoders was tested statically against a calibration plate and dynamically against a video-based motion capture system. Four well-trained cyclists provided data at three pedaling rates. Statically, the ISL had a mean horizontal error of 0.03 ± 0.21 mm and a mean vertical error of −0.13 ± 0.59 mm. Compared with the video-based motion capture system, the agreement of the location of the ASIS had a mean error of 0.30 ± 0.55 mm for the horizontal dimension and −0.27 ± 0.60 mm for the vertical dimension. The ISL system is a cost-effective, accurate, and valid measure for two-dimensional kinematic data within a range of motion typical for cycling.

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Leyre Gravina, Frankie F. Brown, Lee Alexander, James Dick, Gordon Bell, Oliver C. Witard and Stuart D.R. Galloway

Omega-3 fatty acid (n-3 FA) supplementation could promote adaptation to soccer-specific training. We examined the impact of a 4-week period of n-3 FA supplementation during training on adaptations in 1RM knee extensor strength, 20-m sprint speed, vertical jump power, and anaerobic endurance capacity (Yo-Yo test) in competitive soccer players. Twenty six soccer players were randomly assigned to one of two groups: n-3 FA supplementation (n-3 FA; n = 13) or placebo (n = 13). Both groups performed two experimental trial days. Assessments of physical function and respiratory function were conducted pre (PRE) and post (POST) supplementation. Training session intensity, competitive games and nutritional intake were monitored during the 4-week period. No differences were observed in respiratory measurements (FEV1, FVC) between groups. No main effect of treatment was observed for 1RM knee extensor strength, explosive leg power, or 20 m sprint performance, but strength improved as a result of the training period in both groups (p < .05). Yo-Yo test distance improved with training in the n-3 FA group only (p < .01). The mean difference (95% CI) in Yo-Yo test distance completed from PRE to POST was 203 (66–340) m for n-3 FA, and 62 (-94–217) m for placebo, with a moderate effect size (Cohen’s d of 0.52). We conclude that 4 weeks of n-3 FA supplementation does not improve strength, power or speed assessments in competitive soccer players. However, the increase in anaerobic endurance capacity evident only in the n-3 FA treatment group suggests an interaction that requires further study.