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Biomedical subjects

S H Constable

Publications and source records attributed to S H Constable.

27 records · Page 2Linked to original sources
PubMed1983

Maximal exercise and residual lung volume: considerations for body composition analysis.

Pulmonary function was evaluated in 11 female cross country runners before and after maximal treadmill exercise. Hydrostatic weighing was also performed post exercise. Significant increases were found in both residual lung volume (X delta + 210 ml, 20.6%) and total lung capacity (X delta + 170 ml, 3.4%). These changes were not correlated to the intensity of the exercise. The magnitude of the change in residual lung volume resulted in a mean error of 12.1% in body composition prediction. Standardized testing orders are recommended.

Adult↗
PubMed1982

Mechanical and physiological calibration of four cycle ergometers.

Mechanical and physiological calibrations were performed on four research-grade cycle ergometers. Ten subjects rode each ergometer twice in a randomized testing order. The subjects pedaled at 60 rpm for 5 min at each of three power outputs, i.e., 49, 98, and 147 W. Heart rate, metabolic, and perceptual data were obtained each minute. Prior to and immediately following these test rides, mechanical calibrations were obtained in duplicate. From the mechanical calibrations, Ergometer A was approximately 10% below actual values at each power output. Ergometer B demonstrated a variable error, with the largest percentage and absolute errors occurring at the lower power outputs. Ergometers C and D generally demonstrated less than a +/- 3% error. Following the physiological calibration, Ergometer B exhibited a substantial drift in calibration, while Ergometers A, C, and D maintained their original calibration. The physiological data supported the mechanical calibration, and Ergometer B demonstrated a substantial drift between the first and second trials and produced substantially different results compared with the other three ergometers. Ergometers A, C, and D demonstrated acceptable consistency in results both within trials and among ergometers. These results demonstrate the importance of proper calibration and of understanding the calibration characteristics of ergometers selected for research purposes.

Adult↗
PubMed1981

Instructor pilot teaching behavior and student pilot stress in flight training.

The purpose of this study was to investigate the relationship between instructor pilot behavior and student pilot stress. Six instructor pilots and 12 undergraduate pilot training students served as subjects. Two students were assigned to each instructor. Ten categories of instructor pilot behavior were coded from audio cassette tapes made during four sorties from the initial instrument phase of undergraduate pilot training in the T-50 Instrument Flight Simulator. Behaviors were tallied and converted to a rate per minute; inter-recorder agreement was 87%. Instructors who relied heavily on acceptance and praise behaviors were placed in a positive group (N = 4), while those relying on criticism and scolding were placed in a negative group (N = 2). Student stress was estimated from timed urine samples used to quantify catecholamine excretion. Results indicated that missions in the T-50 Instrument Flight Simulator produced a significant stress response in the subjects and that the stress response was greater in lessons taught by the instructor pilots in the negative group.

Aviation↗
PubMed1981

The effect of an acute bout of exercise on selected pulmonary function measurements.

The purpose of this study was to determine and follow the effect of an acute bout of exercise on residual volume (RV) and other pulmonary function measurements over a 24-h post-exercise period, and to evaluate the effect on subsequent body composition calculations. Selected pulmonary function measurements of 12 male college students were collected prior to exercise at 5, 15, and 30 min, and at 1, 2, and 24 h post-exercise. RV was significantly (P less than 0.01) increased 20.8% (260 ml), 16.8% (210 ml) and 12.0% (150 ml) at 5, 15, and 30 min post-exercise, respectively. Total lung capacity (TLC) was significantly (P less than 0.01) increased 2.7% (190 ml) and 2.3% (160 ml) at 5 and 15 min post-exercise, respectively. Subsequent body composition calculations, using the post-exercise RV data, resulted in significantly (P less than 0.01) lower relative body fat measures, as compared to the pre-exercise value, through 30 min of recovery. In conclusion, our data demonstrate apparent increases in RV and TLC immediately following maximal treadmill exercise; these measurements remained significantly increased over pre-exercise values, through 30 and 15 min of recovery, respectively. It is recommended that the RV measurement and the actual hydrostatic weighing procedure not be separated by an acute bout of exercise, and that protocols for long-term studies be standardized.

Adult↗
PubMed1980

Training and acclimatization: effects on responses to exercise in a desert environment.

The purpose of this investigation was to observe differences in responses to work in a desert environment among males representing varying levels of acclimatization and physical training. Three groups of subjects were selected: 1) unacclimatized males (UM), VO2max = 46.8 ml . kg-1 . min-1, 2) acclimatized males (AM), VO2max = 49.6 ml . kg-1 . min-1, and 3) acclimatized-fit males (AFM) VO2max = 65.8 ml . kg-1 . min-1. Each subject sat for 40 min and then walked for 40 min at 3.5 miles/h on a grade which represented his 50% VO2max in a neutral indoor environment (WBGT = 18.1 DEGREES C) and in a desert (hot, dry and sunny) environment (WBGT = 29.9 DEGREES C). The UM experienced consistently higher HR during both rest and work in the heat than did the AM. The AFM exhibited lower HR than either AM or UM during both neutral and hot exposures, despite a higher workload. Both groups of acclimatized subjects possessed lower Tre's than the unacclimatized subjects in the heat. The superior fitness of the AFM gave an advantage in terms of increased sweating sensitivity since they had equal or greater SR at lower Tre. It was concluded that a high level of physical training is an additional and important variable in the ability to tolerate work in the desert.

Acclimatization↗
PubMed1980

Catecholamine excretion in A-10 pilots.

Catecholamine excretion was determined for 15 USAF pilots during surface attack training in the A-10 aircraft. Timed urine samples were used to determine excretion rates of epinephrine and norepinephrine during basal conditions, during five sorties performed in high-realism simulators, and during six actual flights. Catecholamine excretion was significantly elevated (p < 0.05) over basal rates during all 11 training sorties; therefore, it was concluded that A-10 conversion and surface attack training results in a significant stress response in the subjects. The stress response experienced in the simulator diminished across trials; the stress response from aircraft flights remained steady through all sorties monitored. The relative proportions of epinephrine and norepinephrine remained similar across all but the final sorties in both the simulator and the aircraft. These occasions were typified by increased norepinephrine and decreased epinephrine excretion rates.

Aerospace Medicine↗