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G J Bell

Publications and source records attributed to G J Bell.

28 records · Page 2Linked to original sources
PubMed1989

The effect of velocity-specific strength training on peak torque and anaerobic rowing power.

This study investigated the effect of low- and high-velocity resistance training on isokinetic peak torque and anaerobic power output. Eighteen male varsity oarsmen were blocked on peak knee extension torque at 3.14 rad s-1 and assigned to a high-velocity resistance training group (HVR), a low-velocity resistance training group (LVR) or a control group. Subjects trained four times a week for 5 weeks. Each training session included three circuits of 12 stations using variable-resistance hydraulic equipment. The HVR training significantly improved peak torque (P less than 0.05) in knee extension and flexion at 2.61, 3.14, 3.66 and 4.19 rad s-1. The LVR training produced significant improvements (P less than 0.05) in peak torque for knee extension and flexion at 0.52, 1.05, 1.57 and 2.61 rad s-1. High positive correlations were found between peak torque and anaerobic power outputs for all groups. However, no significant changes occurred in 15 s power output, average 90 s power output or peak blood lactate in either training group. These results indicate that velocity-specific strength training does not necessarily improve anaerobic power output in a different exercise mode despite the high positive correlation between isokinetic strength and anaerobic power output.

Adult↗
PubMed1988

The effect of one-legged sprint training on intramuscular pH and nonbicarbonate buffering capacity.

To determine the effect of one-legged sprint training on muscle pH and nonbicarbonate buffering capacity (BC), 9 subjects completed 15 to 20 intervals at 90 RPM, 4 days a week for 7 weeks on a bicycle ergometer adapted for one-legged pedaling. Needle biopsies from the vastus lateralis and blood samples from an antecubital vein were taken at rest and twice during recovery (1 and 4 minutes) from a 60 s one-legged maximal power test on a cycle ergometer. pH one minute after exercise in both the trained and untrained legs following the training period was not different but both were higher than before training. BC increased from 49.9 to 57.8 mumol HCl x g-1 x pH-1 after training (p less than 0.05). Blood lactate levels after exercise were significantly higher for the trained leg when compared to the untrained leg after spring training. Peak and average power output on the 60 s power test increased significantly after training. One-legged aerobic power (VO2max) was significantly increased in the untrained and trained legs. Two-legged VO2max also improved significantly after training. These data suggest that nonbicarbonate buffering capacity and power output can be enhanced with one-legged sprint training. Also, small but significant improvements in VO2max were also observed.

Adult↗
PubMed1988

Sequencing of endurance and high-velocity strength training.

To compare two sequences of endurance (E) and high-velocity resistance (HVR) training, sixteen male oarsmen were separated into Group ES which trained endurance prior to strength and Group SE which trained strength prior to endurance. The endurance program consisted of up to 60 min a session, five days a week for five weeks. HVR exercise was conducted on 12 stations of variable resistance hydraulic equipment, four sessions per week for five weeks. Endurance training significantly improved VO2max and submaximal heart rate and blood lactate responses in both groups regardless of the sequence followed. HVR training improved VO2max in group SE only and had no effect on submaximal response to exercise. Peak torque increases for knee extension and flexion with HVR training were greater in group SE than group ES. These results show that organizing strength and endurance training into sequential programs can influence the physiological adaptation to training.

Adult↗
PubMedDate not supplied

The effect of strength training on estimates of mitochondrial density and distribution throughout muscle fibres.

The purpose of this study was to investigate the effect of strength training (12 weeks, 3 days/week, four lower-body exercises) of young individuals (mean age 23.6 years) on estimates of mitochondrial distribution throughout muscle fibres. A control group (mean age 21. 7 years) was followed simultaneously. Skeletal muscle biopsy samples were obtained from the vastus lateralis, pre- and post-training. The regional distribution of subsarcolemmal and intermyofibrillar mitochondrial populations was determined using quantitative histochemical staining of succinate dehydrogenase (SDH) in type I and II muscle fibres. Strength training resulted in significant increases of 26% and 28% in the cross-sectional area of type I and II fibres, respectively (P < 0.05). Overall SDH activity decreased by 13% with strength training (P < 0.05). The decrease in SDH activity with strength training between fibre types and between subsarcolemmal and intermyofibrillar regions of muscle fibres was not different. Fibre area and SDH activity was unchanged in the control group. We conclude that the muscle hypertrophy associated with strength training results in reduced density of regionally distributed mitochondria, as indicated by the reduction in the activity of SDH.

Adult↗
PubMedDate not supplied

The interactions of intensity, frequency and duration of exercise training in altering cardiorespiratory fitness.

This review has grouped many studies on different populations with different protocols to show the interactive effects of intensity, frequency and duration of training as well as the effects of initial fitness levels and programme length on cardiorespiratory fitness as reflected by aerobic power (VO2max). Within each level of exercise duration, frequency, programme length or initial fitness level, the greatest improvements in aerobic power occur when the greatest challenge to aerobic power occurs i.e., when intensity is from 90 to 100% of VO2max. The pattern of improvement where different intensities are compared with different durations suggests that when exercise exceeds 35 minutes, a lower intensity of training results in the same effect as those achieved at higher intensities for shorter durations. Frequencies of as low as 2 per week can result in improvements in less fit subjects but when aerobic power exceeds 50 ml/kg/min, exercise frequency of at least 3 times per week is required. As the levels of initial fitness improve, the changes in aerobic power decreases regardless of the intensity, frequency or duration of exercise. Although these pooled data suggest that maximal gains in aerobic power are elicited with intensities between 90 to 100% VO2max, 4 times per week with exercise durations of 35 to 45 minutes, it is important to note that lower intensities still produce effective changes and reduce the risks of injury in non-athletic groups.

Aerobiosis↗
PubMedDate not supplied

Moths and butterflies.

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Child, Hospitalized↗