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Biomedical subjects

M Scharff-Olson

Publications and source records attributed to M Scharff-Olson.

10 recordsLinked to original sources
PubMed1998

Bench stepping and running in women. Changes in fitness and injury status.

BACKGROUND: The purpose of this investigation was to evaluate injury rates and changes in VO2peak in women associated with aerobic exercise (bench stepping and running). METHODS: A pretest post-test repeated measures design was used to evaluate changes in VO2peak after training for 10 weeks, 3 days per week, for 1 hour per session. Injury incidence was monitored by questionnaires throughout the training program. SETTING: All testing and training took place at Auburn University Montgomery, Montgomery, AL, USA. PARTICIPANTS: The subjects were women enrolled in university physical activity courses. The exercise groups consisted of 23 women who performed bench exercise and 15 who performed running-jogging. Eleven subjects served as non-exercising controls. INTERVENTION: The 10-week exercise training program served as the intervention. MEASURES: Subjects were both pre- and post-tested for VO2peak by open circuit calorimetry. Body composition was estimated from a 7-site skinfold equation. A daily injury log was maintained to evaluate injury status. RESULTS: A repeated measures ANOVA found similar significant improvements in VO2peak for both the bench and running groups with no change for the control group. An evaluation of the injuries graded II or higher found 0.29 injuries per 100 hrs for the bench group and 0.66 injuries per 100 hrs for the running group. When all complaints were considered (grade I to grade IV) the rates increased to 2.44 per 100 hrs for the running group and 6.09 per 100 hrs for the bench group. CONCLUSIONS: Aerobic bench exercise produced similar changes in VO2peak compared to running. The results indicated that the primary injury complaints were grade I and related to delayed onset muscle soreness (DOMS). The bench group experienced an greater incidence of grade I complaints while the running group experienced a slightly greater incidence of more serious grade II or higher injuries.

Adult↗
PubMed1997

Vertical impact forces during bench-step aerobics: exercise rate and experience.

The purpose of this study was to determine the effects of two bench-step exercise speeds on vertical impact forces and to explore this variable between novices, and instructors. 12 women (mean age 24 yr.) randomly performed 8-min. protocols of the "basic" bench-stepping technique and a more advanced "travel" technique at 30 and 33 cycles.min.-1. Analysis showed that the faster exercise rate yielded significantly higher vertical impact forces on a reference (B-8) step height (20.3 cm). At 33 cycles.min.-1, the instructors, and novices' responses were both higher than those at 30 cycles.min.-1. The mean peak vertical impact force ranged from 1.54 times the body weight for the novice group at 30 cycles.min.-1 to 1.87 times the body weight for instructors at 33 cycles.min.-1. A comparison of the groups' force curves showed a distinctive pattern in the loading of the impact forces. Specifically, the instructors consistently produced a transitory decrement in force prior to attaining peak force. In addition, the novices exhibited nonuniform increases in the production of vertical impact force across other step heights at the faster (33 cycles.min.-1) speed. Thus, experience with bench-step exercise may afford an ability to make uniform and force-absorbing adjustments in the resultant vertical impact forces at increased speeds.

Adult↗
PubMed1996

Injury rates and physiological changes associated with lateral motion training in females.

The purpose of this investigation was to evaluate physiological changes and injury rates associated with lateral motion (slideboard) training. Twenty-five females performed slideboard exercise 3 days per week, 1 hour each session, over a 10 week period. Eleven females served as controls. The subjects were pre and post tested via treadmill exercise to determine VO2peak. Body composition was analyzed by a seven-site skinfold equation. The slideboard subjects (SBS) were evaluated daily for injury incidence. A factorial repeated measures ANOVA (p < 0.05) revealed a significant 14% increase in VO2peak. No significant modifications were shown for body composition. The incidence of injury was 80% for Grade I injuries, 52% for Grade II injuries, 0% for Grade III injuries, and 4% for Grade IV injuries. Thus, the primary injury reports were of a Grade I and Grade II level of severity. The present injuries were largely associated with delayed onset muscle soreness (DOMS) in the medial leg musculature during the first two weeks of training. These results show that during a 10 wk training program lateral motion exercise is an effective mode for improving cardiorespiratory fitness. In addition, the risk of incurring an injury requiring medical attention appears to be quite low. However, untrained women who perform this activity at a frequency, duration, and intensity similar to the present study may experience muscle soreness during the initial period of training.

Adult↗
PubMed1996

Cross-validation of non-exercise predictions of VO2peak in women.

The purpose of this investigation was to cross-validate non-exercise (N-Ex %fat and N-Ex BMI) models for predicting VO2peak in females, and to evaluate the validity of these models in estimating fitness status, based on a < 9 METs cardiovascular fitness/health-risk criterion. Subjects were 165 females who completed the PA-R activity scale and were evaluated for VO2peak and body composition. The cross-validation statistics for the N-Ex %fat and N-Ex BMI models were: ryy' = 0.86, E = 6.3 (ml.kg-1.min-1), and ryy' = 0.81, E = 6.9 (ml.kg-1.min-1), respectively. Both models were found to accurately identify 87% of the subjects with VO2peak < 9 METs. The statistics associated with the < 9 MET criterion were: ryy' = 0.73, E = 3.4 (ml.kg-1.min-1), and ryy' = 0.80, E = 4.5 (ml.kg-1.min-1), for N-Ex %fat and N-Ex BMI, respectively. The N-Ex models yielded values similar to those reported previously (Jackson, A. S., S. N. Blair, M. T. Mahar, L. T. Wier, R. M. Ross, and J. E. Stuteville. Prediction of functional aerobic capacity without exercise testing. Med. Sci. Sports Exerc. 22:863-870, 1990). When exercise testing is not an option, the present N-Ex models provide an alternative method for predicting VO2peak in females.

Adolescent↗
PubMed1996

The physiological effects of bench/step exercise.

Recent investigation of acute cardiorespiratory responses to the current 'popularised' style of bench/step exercise has validated its use in improving aerobic physical fitness, particularly in women. However, no marked differences in relative measures of cardiorespiratory demand have been reported between men and women. Instructor data and training investigations further substantiate the effectiveness of bench/step exercise in promoting physical fitness, including upper body strength. However, the energy cost of bench/step exercise can vary dramatically. Important factors include, the selected step height, exercise rate, imposed step manoeuvre, routine format and use of hand-held weights. Hand-held weights may be more useful for men than woman. During training, bench/step exercise has been reported to yield a high incidence of grade I injury complaints, particularly in the calf and shoulder region. However, nearly 90% of these complaints were attributable to acute muscle soreness. Few serious injuries have been associated with the activity. Biomechanical research has shown that the ground reaction forces (GRF) experienced during bench stepping are lower than running and directly related to the step height and type of manoeuvre. In addition, compared with novices, instructors exhibit a moderation in the GRF pattern generated during landing. This suggests that a learning effect has occurred and that teachers yield a more consistent landing pattern. Finally, the activity may be effective in improving body composition, but a consideration of factors related to energy expenditure (e.g. exercise duration and dietary control) appear to be important in regimens prescribed for modifying body fat.

Athletic Injuries↗
PubMed1995

The metabolic responses of slideboard exercise in females.

Recently, slideboard exercise training has been introduced as a mode of aerobic training. The purpose of the investigation was to determine the acute cardiovascular and metabolic responses to slideboard exercise. Subjects consisted of 20 healthy females with a mean age of 26.5 +/- 7.9 years, and a VO2max of 40.8 +/- 5.6 ml.kg-1.min-1. The results of the investigation showed that 10 min of a commercially produced slideboard routine elicited mean heart rate (HR) responses ranging from 160 to 168 beats.min-1 and VO2 values of 27.5 to 33.5 ml.kg-1.min-1. A sub-group of 10 subjects was also evaluated while performing sliding exercise at different sliding rates (SR). Subjects performed the standard slide technique at metronome cadences of SR-40, SR-50, and SR-60 slide.min-1. As sliding rate increased so did HR and VO2. The subjects demonstrated mean responses of approximately 55 to 81% of VO2max for the slower to the most rapid sliding rates, respectively. Compared to treadmill exercise at the same oxygen consumption levels, the heart rates for sliding were approximately 15% higher. Slideboard exercise can be an alternative mode of aerobic training.

Adult↗
PubMed1992

The heart rate VO2 relationship of aerobic dance: a comparison of target heart rate methods.

The purpose of this study was to examine the relationship between heart rate (HR) and oxygen consumption (VO2) for aerobic dance exercise. Therefore, eleven females completed 20 minutes of aerobic dance with continuous monitoring of HR and VO2. These physiological responses were analyzed with correlation/regression techniques. The results showed that for aerobic dance to produce a response in excess of 50% of VO2 max, the target HR must be approximately 80% of the age-predicted HR max or greater. In contrast, previously reported data for treadmill running shows that 50% of VO2 max is achieved at approximately 65% of age-predicted HR max in females. The maximum heart rate reserve (Karvonen) method was also found to underestimate the actual VO2 of AD. With the Karvonen method, the target heart rate must approximate 65% of maximum HR reserve in order to elicit a VO2 response which is representative of 50% of VO2 max. These data support recent research which illustrates that target heart rate prescriptions derived from treadmill testing may fail to accurately place AD participants in the recommended training zone.

Adult↗
PubMed1989

The physiological effects of aerobic dance. A review.

Aerobic dance exercise is currently one of the most commonly practised adult fitness activities. The majority of the research pertaining to this form of exercise supports its application as a valid cardiovascular training alternative, especially for adult females if performed according to the American College of Sports Medicine (ACSM) guidelines. If, however, the participant is interested in modifying body composition, training frequency, duration, or efforts toward caloric restriction may need to be increased or altered beyond those employed in the aerobic dance training investigations. The amount of energy expended during a bout of aerobic dance can vary dramatically according to the intensity of the exercise. 'Low intensity' dance exercise is usually characterised by less large muscle activity and/or less lower extremity impact, and music of slower tempo. Dance exercise representative of this variety requires a cost of approximately 4 to 5 kcal/minute. Several trials, however, have shown that vigorous 'high intensity' aerobic dance which entails using the large muscle groups can require 10 to 11 kcal/minute. The associated training outcomes could be affected by such differences in dance exercise intensity and style.

Adult↗
PubMedDate not supplied

Physical and performance characteristics of successful high school football players.

The purpose of this investigation was to determine the performance and physiologic characteristics of a "successful" American high school football team, and to compare the present values with values reported for other groups of high school, college, and professional players. For descriptive purposes, players were divided into two groups: backs (N = 8) and linemen (N = 10). Maximal aerobic power (VO2max) was determined from a maximal treadmill test, and body composition was evaluated by hydrostatic weighing. Maximal strength values were evaluated by one-repetition maximum bench press and squat test; the sit-and-reach test was used to measure flexibility. Speed and power were evaluated by a vertical jump and a 36.6-meter sprint. Results indicate that compared with other groups of college and professional players, as the level of competition increases so do height, weight, and fat-free weight of the players. Similar maximum oxygen consumption values were found for the present group when compared with other groups of these players. From the strength and power standpoint, football players at all levels are becoming stronger. Incorporation of strength training programs has greatly improved strength and performance profiles of football players at all levels of competition.

Adipose Tissue↗