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Biomedical subjects

R Serfass

Publications and source records attributed to R Serfass.

7 recordsLinked to original sources
PubMed1994

Comprehensive evaluation of the Minnesota Leisure Time Physical Activity Questionnaire.

The accuracy of the Minnesota Leisure Time Physical Activity (LTPA) Questionnaire (a 1-year survey of non-occupational activity used in MRFIT) was studied in 78 men and women, age 20-59 years, by comparing survey results to the following measures obtained over a year's duration: six 48-hour physical activity records; fourteen 48-hour Caltrac accelerometer readings (Caltrac); 14 administrations of a 4-week version of the LTPA Questionnaire (FWH); 3 VO2peak determinations and percent body fat (% BF). The LTPA Questionnaire demonstrated: weak to moderate associations with % BF (r = -0.24) and with VO2peak (r = 0.47); a weak association with Caltrac readings expressed as MET.minutes.day-1 (r = 0.23); strong associations with corresponding activities reported on the FWH; and moderate associations with total and heavy activities reported in the physical activity record, but no associations with moderate and light activities. Furthermore, several types of LTPA were found to be either under-represented or not currently included in the Minnesota LTPA Questionnaire. It is concluded that although validation results were found to be quite good, several possible refinements were identified, which should improve the accuracy of the Minnesota LTPA Questionnaire in assessing habitual physical activity.

Adipose Tissue↗
PubMed1992

The effects of a hockey-specific training program on performance of Bantam players.

Few studies have attempted to identify the effects of training on performance measures related to ice hockey. The present study was designed to examine the effects of a 7-week hockey-specific training program on the on- and off-ice test performance scores of 14- and 15-year-old (Bantam) hockey players. Pre- and post-training tests of percent fat (ultrasound), center of gravity location, 40-yard dash, vertical jump, and on-ice tests of top speed, acceleration, and concerning ability were completed on 28 male subjects (16 in a training group, 12 in a control group of summer league participants). The training group showed significant improvements (p less than .01) in percent fat, top speed, acceleration, and cornering test performance whereas only percent fat was significantly improved for the control group. The results suggest that performance on tests related to ice hockey can be improved by training specifically for hockey but that performance is not affected by summer league play alone.

Adolescent↗
PubMed1989

Quadriceps strength training using two forms of bilateral exercise.

The purpose of this study was to determine the effectiveness of quadriceps strength training in 15 women using bilateral constant resistance computerized exercise equipment that enabled only concentric contractions. To facilitate this investigation, data from an experimental control group (n = 14), using bilateral variable resistance exercise equipment which enables both concentric and eccentric muscle contractions, and a nonexercise control group (n = 17) were incorporated into the study design. Through a random selection process, subjects were assigned to one of three groups that participated in this 10-week study. Analysis, including univariate and multivariate statistical techniques, revealed no significant changes in strength between the two experimental groups. However, compared with the nonexercise group, there were significant increases in strength in the experimental exercise groups; yet, these increases were significant in both groups only on the right legs. In addition, the development of transient knee pain in two subjects engaged in both concentric and eccentric exercise training required their removal from the study. This finding, in concert with previous experimental evidence of an association between eccentric exercise and the development of transient pain, must be integrated into future studies. Results suggest that further investigation is necessary to reveal the neurologic or biomechanical factors which may result in unequal training stimuli to the limbs with bilateral strength training on various types of equipment.

Adult↗
PubMed1979

Effects of a vigorous walking program on body composition, and carbohydrate and lipid metabolism of obese young men.

With no attempt made to influence their diet, six sedentary obese men ages 19 to 31 completed 16 weeks of vigorous walking 90 min, 5 days/week, on a treadmill at up to 3.2 mph on a 10% grade, expending about 1100 kcal per session. Body composition studies indicated a loss of 5.9 kg of body fat and a gain of 0.2 kg of lean tissue for a net loss of 5.7 kg. Percentage body fat decreased from 23.3 to 17.4. Monitored food intake initially increased, then progressively decreased below pretraining levels. Work capacity and cardiovascular efficiency improved with training. Plasma cholesterol and triglyceride concentrations were not significantly changed; however, high density lipoprotein cholesterol progressively increased to 15.6% above pretraining levels and the high/low density lipoprotein ratio increased 25.9%. Fasting blood sugar was significantly lower after training. Blood glucose concentrations after a glucose challenge did not significantly change, but a 43% reduction in plasma radioimmunoassay insulin levels and a 36% decrease in the ratio of insulin/glucose concentration occurred. Thus, vigorous regular walking resulted in a reduction of body fate stores, endogenous insulin requirements, and food intake, and perhaps improved the ability to eliminate cholestrol by increasing the plasma high density lipoprotein fraction.

Adipose Tissue↗
PubMedDate not supplied

Ability of the Caltrac accelerometer to assess daily physical activity levels.

PURPOSE: The purpose of this study was to determine the ability of the Caltrac accelerometer to assess habitual daily physical activity levels. METHODS: The ability of the Caltrac accelerometer to assess 24-hour physical activity (PA) levels was studied in 28 men and 50 women, age 20 to 59 years, with varying levels of self-reported PA. Twelve days of Caltrac readings obtained over 1 year's duration were compared to simultaneously recorded 48-hour PA records. Additionally, 28 days of Caltrac readings obtained over 1 year's duration were compared to mean values of the following validation measures assessed repeatedly over a 1-year period: a 4-week version of the Minnesota Leisure Time Physical Activity Questionnaire (FWH); VO2peak; and percent body fat. RESULTS: The Caltrac measurements of movement (in MET minutes per day-1) were significantly associated with the following: PA record indices of total (r = .51) and heavy (r = .34) and PA; FWH indices of total (r = .30), heavy R = .36) and moderate (r = .23) PA;, and VO2peak (r = .24). However, the Caltrac measurements of caloric PA record and FWH indices of PA, although there were directly associated with percent body fat (r = .50) and inversely associated with VO2peak (r = -.26). CONCLUSIONS: Caltrac measurements of movement exhibited a moderate associated with several criterion measures related to habitual PA, whereas Caltrac measurements of total energy expenditure, were not reflective of varying levels of PA.

Activities of Daily Living↗