Cardiorespiratory and perceptual responses to arm crank and wheelchair exercise using various handrims in male paraplegics.

The purpose of the present study was to determine the effects of 10-in [0.25-m] versus 16-in [0.41-m] wheelchair handrims on cardiorespiratory and psychophysiological exercise responses during wheelchair propulsion at selected velocities. Fifteen male paraplegics (27.0 +/- 5.5 yrs) performed three discontinuous exercise tests (ACE = arm crank ergometer; WERG = wheelchair roller ergometer) and two 1600-m performance-based track trials (TRACK) under simulated race conditions. There were no significant differences in HR, VO2, VE, HLa, or category-ratio ratings of perceived exertion (RPE) using different handrims during wheelchair propulsion at 4 km.h-1. In contrast, at 8 km.h-1 subjects demonstrated a 13% lower steady state VO2 (p less than .05) using the 10-in handrims, coincident with a 23% lower VE. Steady state HR during WERG at 8 km.h-1 using the 10-in (124.4 +/- 3.9 b.min-1) or 16-in (130.6 +/- 4.6 b.min-1) handrims were not significantly different. There were also no significant differences between ACE or WERG conditions during maximal effort for VO2 or VE. However, HRpeak during ACE was 7% higher than HRpeak during WERG16 (183 +/- 15 b.min-1 vs. 171 +/- 12 b.min-1, p less than .05), and whole blood HLa during ACE was also significantly higher (by 2.3-2.5 mmol; p less than .05) compared to WERG. There were no significant differences for HR, performance time, or RPE between trials using different handrim diameters during the 1600-m event.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study of the dynamic, static, and rotary balance of deaf and hearing children.

The purpose of the present study was to measure the dynamic, static and rotary balance of deaf and hearing children. 20 deaf and 20 normal hearing students matched for mean age of 123 +/- 5.9 or 5.6 mo. and sex (11 boys, 9 girls) performed three tests of balance. A series of Wilcoxon signed-ranks tests and a Kendall Tau were applied to assess whether balance was affected in sensorineural deafness and to assess whether age and sex were factors in over-all balance, respectively. Significant differences were noted between groups for dynamic balance and rotary balance. Although not significant, there was a difference of 57.8% in number of trials for successful completion of static balance in favor of the hearing children. In the present study, over-all balance in deaf children was significantly inferior to the balance in hearing children. Knowledge of these differences may aid those working with deaf children in physical education.

Increased bone calcium following endurance exercise in the mature female rat.

In order to determine the effects of exercise on the calcium status of selected axial and appendicular bones of mature rats, female Sprague-Dawley rats (8-9 mo.) were divided into three groups including, two months (E2, n = 8) or four months (E4, n = 9) of exercise, and four month sedentary controls (S, n = 10). Exercise consisted of treadmill running for 1 hr/day, 5 days/wk at a speed of 14.1 m/min and 8 degrees elevation. After sacrifice all femurs, tibia/fibula complexes, ribs (T7), and vertebrae (T7) were excised, cleaned, weighed and measured for length and volume. After freeze-drying and bone hydrolysis in 5N HCl, total bone calcium contents and concentrations were determined spectrophotometrically. The acid soluble, appendicular bone calcium contents of the E4 group were significantly greater than S for the femur and tibia respectively: E4 = 159.78 +/- 3.44 mg (mean +/- SEM), 129.46 +/- 4.87 mg; S = 140.03 +/- 5.04 mg, 110.40 +/- 4.71 mg. Bone calcium concentration (mg/g dry bone) also was significantly greater in the tibia/fibulas, ribs and vertebrae of the E4 group than the S group. With respect to other training-induced effects, the oxygen carrying capacity of the blood, as well as the heart and lung DNA and protein concentrations did not change after four months of exercise training. Within four months, moderate exercise can increase the calcium deposition in the bones of mature, female rats.

Morphometry and calcium contents in appendicular and axial bones of exercised ovariectomized rats.

To determine the effects of exercise and ovariectomy on calcium status in selected appendicular and axial bones, female Sprague-Dawley (8-9 mo) rats were assigned to groups based on the following combinations: control (C) or ovariectomized (O); sedentary (S) or exercised (E); and length of treatment (2 or 4 mo). Exercise consisted of treadmill running for 1 h/day, 5 days/wk at a speed of 14.1 m/min and 8 degrees elevation. After death, femurs, tibia-fibula complexes, ribs (T7), and vertebrae (T7) were excised, cleaned, and weighed, and selected morphometrics were measured. Tensile strength was measured for the femurs, and all bones were then acid-hydrolyzed and calcium concentration determined spectrophotometrically. Bone [Ca2+] was significantly greater for CE and OE animals when compared with their sedentary counterparts (CS, OS). Within 4 mo calcium losses were evident in the femur and tibia of the ovariectomized animals, and the moderate exercise program was of insufficient intensity to alter this loss. The average stress to failure for femur from all groups was 1.13 +/- 0.11 N/m2. However, the effects of exercise appeared beneficial in the axial bones where [Ca2+] increased in the ovariectomized animals.