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Biomedical subjects

D L Ballor

Publications and source records attributed to D L Ballor.

26 records · Page 2Linked to original sources
PubMed1990

Body composition, muscle and fat pad changes following two levels of dietary restriction and/or exercise training in male rats.

This study examined the effects of exercise training on conservation of lean mass during moderate and severe dietary restriction in male Sprague-Dawley rats. Eight rats each (48 total) were assigned to one of three levels of dietary restriction (ad lib., AL; moderate, MR; severe, SR) and to one of two activity levels (cage-confined, CC; or treadmill exercised, E) for a 10-week period. Post-intervention, the AL-E (91 percent), MR-CC (84 percent), MR-E (86 percent), SR-CC (66 percent) and SR-E (68 percent) groups all weighed less than the AL-CC group (427 +/- 4.3 g). Exercise training resulted in conservation of lean mass (protein + water + ash) at the moderate but not severe levels of dietary restriction. Further examination showed that this was mostly water since no between-group differences existed at any given diet level for protein or ash mass. Exercise training did elicit conservation of left ventricular heart muscle mass at both the moderate and severe levels of dietary restriction. In contrast, gastrocnemius muscle mass was conserved or maintained only at the moderate dietary restriction level. Thus, the level of dietary restriction appears to affect the ability of exercise training to elicit conservation of both total lean mass and the mass of individual muscles during diet-induced body mass reduction.

Adipose Tissue↗
PubMed1990

Neither high- nor low-intensity exercise promotes whole-body conservation of protein during severe dietary restrictions.

The effects of 11 weeks of severe dietary restriction alone or in combination with either high- or low-intensity exercise on conservation of protein were studied in 32 male Sprague-Dawley rats. The rats were assigned to one of four groups: sedentary control (C), diet restriction alone (DO) or diet restriction in combination with either high-intensity (HI) or low-intensity (LO) exercise. The groups trained at either 75 percent (HI) or 37.5 percent (LO) of maximal running speed for up to 45 or 90 min/day, 5 days/week, respectively. Total (g) proteins, fat, water and ash content did not differ between the DO, HI and LO groups and were all reduced significantly in comparison to C. Similarly, heart, gastrocnemius muscle and epididymal fat pad masses were significantly reduced for the DO, HI and LO groups in comparison to C. However, the absolute decrease in heart mass was reduced for the HI group (heart mass = 0.31 percent of body mass) in comparison to the DO group (heart mass = 0.28 percent of body mass). Thus, in lean rats undergoing severe dietary restrictions, neither high- nor low-intensity exercise appears to affect total protein conservation in comparison to diet alone. However, high-intensity exercise training appears to attenuate cardiac but not skeletal muscle mass loss in the face of severe dietary restriction.

Animals↗
PubMed1989

Strength gains in obese females are unaffected by moderate dietary restriction.

This study examined the effects of dietary restriction on strength gains from whole body resistance training. Comparisons were made between diet-restricted (n = 12) and non-diet-restricted (n = 10) obese women (mean +/- SD, 36.7 +/- 7.0% fat) undergoing identical 8-week resistance training regimens. Diet-restricted subjects reduced their dietary intake by 4200 kJ/day and reduced body mass by 3.9 kg over 8 weeks. Ten-repetition maximum masses were compared between the groups on biweekly intervals. Results indicated no differences between the groups with respect to the rate or magnitude of strength gains for any of the eight exercises. Significant pre- to post-test increases in strength (p less than 0.05) were found for all eight exercises. The rate or magnitude of strength gains induced by resistance training does not appear to be affected by moderate dietary restrictions in obese females.

Adult↗
PubMed1989

Comparison of three methods of estimating energy expenditure: caltrac, heart rate, and video analysis.

This study examined the accuracy of a new device (Caltrac) in estimating energy expenditure via acceleration measurements. Energy expenditure of 20 high school students during basketball class activity (average length = 37 min) was estimated using the Caltrac, heart rate recording, and video analysis. Heart rate recording and video analysis estimates of energy expenditure were determined from heart rate, caloric expenditure curves, and an activity rating scale, respectively. The following estimates of caloric expenditure (M +/- SD) were found: heart rate recording = 196 +/- 73 greater than Caltrac = 163 +/- 49 greater than film analysis = 123 +/- 30 kcal (p less than .05). Laboratory simulations of the basketball activity revealed that the Caltrac energy expenditure was not significantly different from the actual energy expenditure (p greater than .05). The heart rate recording and video analysis estimates of energy expenditure were significantly (p less than .05) higher and lower, respectively, than the actual energy expenditure. The Caltrac is a lightweight, low-cost device that provides a relatively accurate estimate of energy expenditure in free-ranging activities, such as basketball.

Adolescent↗
PubMed1989

Physiological responses to nine different exercise:rest protocols.

This study determined the metabolic responses to different exercise:rest protocols during circuit exercise using hydraulic resistance. In experiment 1, nine subjects underwent nine different 27 min exercise circuits. There were three variations of three exercise:rest protocols (2:1, 1:1, 1:2). The VO2 for the nine circuits averaged (mean +/- SEM) 1.94 +/- 0.03 l.min-1 (43% of treadmill VO2max), with the largest difference between the protocols being 13%. Heart rate averaged 152.2 +/- 3.1 beats.min-1, with the largest difference between the protocols being 8%. Increasing the exercise duration per minute or the number of exercise bouts per minute had minimal effects on the mean VO2 and heart rate response to hydraulic resistive exercise. In experiment 2, nine subjects underwent three different 9 min exercise circuits using exercise:rest protocols of 2:1, 1:1, and 1:2 while work and VO2 were simultaneously measured. Surprisingly, increases in work were not necessarily accompanied by corresponding increases in VO2.

Adult↗
PubMed1988

Resistance weight training during caloric restriction enhances lean body weight maintenance.

To assess the individual and combined effects of weight loss and weight training on body weight and body composition, 40 obese women were randomly assigned to one of four groups for an 8 wk weight-loss study. These groups were control (C); diet without exercise (DO); diet plus weight training (DPE); and weight training without diet (EO). Body weight decreased for DO (-4.47 kg) and DPE (-3.89 kg) compared with C (-0.38 kg) and EO (0.45 kg). Lean body weight (LBW) increased for EO (1.07 kg) compared with DO (-0.91 kg) and C (-0.31 kg) and for DPE (0.43 kg) compared with DO. Upper-arm muscle areas (determined by radiograph) increased for DPE (11.2 cm2) and EO (10.4 cm2) compared with C (2.7 cm2) and DO (2.1 cm2). It was concluded that weight training results in comparable gains in muscle area and strength for DPE and EO. Adding weight training exercise to a caloric restriction program results in maintenance of LBW compared with DO.

Adult↗
PubMed1987

Metabolic responses during hydraulic resistance exercise.

Thirteen college-age men under-went a treadmill (TM)-graded VO2max exercise test on 1 d and a 24.5-min hydraulic resistive exercise circuit on a following day. Seven exercises were performed in the following order: leg extension, bent-over row, bicep curl, squat, upright row, bench press, and behind-neck press. Each exercise was performed three times with the following work-to-rest timing: 30 s exercise, 30 s rest; 30 s exercise; 30 s rest; and 30 s exercise, 60 s rest (to allow for machine switch-over to the next exercise). Thus, each exercise took a total of 120 s, of which work was for 90 s and rest 120 s. During the circuit, heart rate averaged 153.8 b X min-1 (81.2% of TM max) and VO2 averaged 1.93 l X min-1 (41.4% of TM max). Oxygen uptake for the individual exercises ranged from 1.52 l X min-1 (32.6% of TM max) for the behind-neck-press exercise to 2.43 l X min-1 (52.1% of TM max) for the squat exercise. Heart rate ranged from 135.9 b X min-1 (71.8% of TM max) for the leg extension exercise to 163.4 b X min-1 (86.3% of TM max) for the squat exercise. Hydraulic circuit resistance exercise results in an average caloric expenditure of 40.8 kJ X min-1 (9.75 kcal X min-1).

Adult↗