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John Scriven, Josephine Cabot, Demri Mitchell and David Kennedy

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John A. Nyland, Dean P. Currier, J. Michael Ray and Mitchell J. Duby

This paper discusses function changes during an accelerated rehabilitation program at 6, 10, and 52 weeks postsurgery for a college athlete following anterior cruciate ligament reconstruction/meniscectomy of the left knee. The effects of combined pulsed electromagnetic field (PEMF) and neuromuscular electrical stimulation (NMES) on knee extensor torque, thigh girth, and pain level are presented. PEMF-NMES decreased stimulation pain by 76%. Knee extensor isometric torque increased by 23%, and thigh girth decreased less than 5% at 6 weeks. Knee extensor isokinetic torque was 13% and 3% deficient at 90°/s and 240°/s, and standing single-leg broad jump distance was 19% deficient at 10 weeks. Knee extensor isokinetic torque was 1% and 1.5% greater at 90°/s and 240°/s, and standing single-leg broad jump distance was 11% deficient at 52 weeks. Knee anterior laxity was 2 mm at 10 weeks and 3 mm at 52 weeks. PEMF-NMES appears to comfortably enhance knee extensor torque gains and diminish thigh girth loss. Despite early return to practice, functional deficit remained and anterior laxity was increased at 52 weeks.

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Nicola Furlan, Mark Waldron, Kathleen Shorter, Tim J. Gabbett, John Mitchell, Edward Fitzgerald, Mark A. Osborne and Adrian J. Gray

Purpose:

To investigate temporal variation in running intensity across and within halves and evaluate the agreement between match-analysis indices used to identify fluctuations in running intensity in rugby sevens.

Methods:

Data from a 15-Hz global positioning system (GPS) were collected from 12 elite rugby sevens players during the IRB World Sevens Series (N = 21 full games). Kinematic (eg, relative distance [RD]) and energetic (eg, metabolic power [MP]) match-analysis indices were determined from velocity–time curves and used to investigate between-halves variations. Mean MP and RD were used to identify peak 2-minute periods of play. Adjacent 2-minute periods (prepeak and postpeak) were compared with peak periods to identify changes in intensity. MP and RD were expressed relative to maximal oxygen uptake (V̇O2max) and speed at V̇O2max, respectively, and compared in their ability to describe the intensity of peak periods and their temporal occurrence.

Results:

Small to moderate reductions were present for kinematic (RD; 8.9%) and energetic (MP; 6%) indices between halves. Peak periods (RD = 130 m/min, MP =13 W/kg) were higher (P < .001) than the match average (RD = 94 m/min, MP = 9.5 W/kg) and the prepeak and postpeak periods (P < .001). RD underestimated the intensity of peak periods compared with MP (bias 16%, limits of agreement [LoA] ± 6%). Peak periods identified by RD and MP were temporally dissociated (bias 21 s, LoA ± 212 s).

Conclusions:

The findings suggest that running intensity varies between and within halves; however, the index used will influence both the magnitude and the temporal identification of peak periods.

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Mohanraj Krishnan, Andrew N. Shelling, Clare R. Wall, Edwin A. Mitchell, Rinki Murphy, Lesley M.E. McCowan and John M.D. Thompson

Purpose: The decline of physical activity in children is considered an important determinant to explain the rising rates of obesity. However, this risk may be augmented in children who are genetically susceptible to increased weight gain. We hypothesized that a sedentary lifestyle and moderate activity will interact with genetic loci, resulting in differential effects in relation to obesity risk. Methods: We recruited 643 European children born to participants in the New Zealand-based Screening for Pregnancy Endpoints (SCOPE) study. Seventy gene variants were evaluated by the Sequenom assay. Interaction analyses were performed between the genetic variants and the activity type derived from actigraphy, in relation to percentage body fat. Results: We found a statistically significant association between increased proportions of sedentary activity with increased percentage body fat scores (P = .012). The OLFM4-9568856 (P = .01) and GNPDA2-rs10938397 (P = .044) gene variants showed genotype differences with proportions of sedentary activity. Similarly, the OLFM4-9568856 (P = .021), CLOCK-rs4864548 (P = .029), and LEPR-1045895 (P = .047) showed genotype differences with proportions of moderate activity. We found evidence for unadjusted gene-by-activity interactions of SPACA3/SPRASA-rs16967845, PFKP-rs6602024, and SH2B1-rs7498665 on percentage body fat scores. Conclusions: These findings indicate a differential effect of physical activity in relation to obesity risk, suggesting that children genetically predisposed to increased weight gain may benefit from higher levels of moderate activity.