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Biomedical subjects

R C Krejci

Publications and source records attributed to R C Krejci.

4 recordsLinked to original sources

Psychological and behavioral differences among females classified as bulimic, obligatory exerciser and normal control.

The compulsion to maintain a lean body shape while living in a society obsessed with food may encourage the use of dieting, binge eating and purging behaviors in young women. The body of literature on bulimia nervosa (Boskind-Lodahl and Sirlin 1977; Fairburn and Cooper 1984; Katzman and Wolchik 1984; Scott 1988) clearly establishes its relationship to the current American fashion for thinness and the value placed on physical attractiveness for self-esteem. This notion promotes a multitude of weight control strategies ranging from self-starvation (Humphrey 1983; Brownell and Foreyth 1986) to cigarette smoking (Klesges and Klesges 1988), many of which may have a profound influence on maintenance of good health. Similar to weight control, exercise behavior could be viewed as falling on a continuum from reasonable efforts to maintain physical fitness to a preoccupation with exercise that is far out of proportion to the expected benefits of a 30-minute, three to five day a week routine. Characteristics of obligatory exercise have been described by several researchers and include maintaining a rigid schedule of intense exercise; resisting temptation to lapse into nonexercising; feelings of guilt and anxiety when the exercise schedule is violated; compensatory increase in exercise to make up for lapses; pushing oneself even when tired, ill, or injured; mental preoccupation with exercise; and detailed recordkeeping on exercise (Yates et al. 1983; Blumenthal et al. 1984; Nudelman et al. 1988). In a competitive society, obsessive exercise behaviors may be linked to the development of rigid dietary guidelines while one strives toward the "optimal" lean-fat ratio of body composition.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Changes in intraocular pressure during acute exercise.

The effect of vigorous physical activity on intraocular pressure has been well documented. Other studies have only focused on pretest and posttest measurements of intraocular pressure. This study presents a continuous evaluation of intraocular pressure during exercise and correlates changes in intraocular pressure with changes in heart rate through time. A total of 17 adult male and female subjects were submaximally tested on a bicycle ergometer using the Astrand-Rhyming protocol. The results of this test were used to design an individualized four-stage workload that would proportionally take each subject to 85% of a predicted maximum heart rate. During this test, intraocular pressure was measured at the end of each stage and through 15 min of recovery with an American Optical non-contact tonometer. A statistically significant decrease (p less than 0.05) in intraocular pressure was noted at the end of the fourth stage and during 1, 5, and 10 min of recovery; however, no trend was found to indicate a significant correlation between heart rate and intraocular pressure.

Adolescent↗

Physical fitness and intraocular pressure.

The ability of moderate to intense aerobic exercise to reduce intraocular pressure (IOP) has been reported. Previous studies have focused on a single postexercise recovery period not considering the long-term effect of improved physical fitness on IOP. A total of 32 adult subjects, all having IOP's of greater than 18 mmm Hg in each eye as determined by an American Optical Corporation Non-Contact Tonometer, were selected for the study. After a complete medical and visual evaluation, participants were randomly assigned to either an intervention group (N = 18) receiving a 6-month supervised exercise program to improve physical fitness or into a control group (N = 14). After 6 months, each group was reevaluated to observe changes in physical fitness and IOP. Pre- and poststudy measurements of maximum oxygen uptake (ml/kg/min) made with a Beckman O2 analyzer showed significant improvement in physical fitness in the intervention group (p less than 0.05). There was a significant decrease (p less than 0.05) in IOP, 2.0 mmm Hg in the right eye and 1.3 mm Hg in the left eye, in the intervention group; however, decreases in IOP were comparable and significant (p less than 0.05) in the control group. Results from multiple regression analysis for each individual group and for combined groups indicated that changes in IOP were not dependent upon changes in physical fitness.

Adult↗