Optimal test characteristics for maximal anaerobic work on the bicycle ergometer.
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Biomedical subjects
Publications and source records attributed to A Weltman.
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Forty-seven active boys and girls, 7 to 12 years of age, underwent a comprehensive medical and physical evaluation in order to assess their prevalence of single and multiple coronary heart disease risk factors. Each subject received a densiometric determination of body composition, blood lipid analysis, pulmonary function and a physical work capacity test to assess their peak oxygen consumption (Vo2max). Obesity (greater than 25% fat), elevated triglycerides (greater than 100 mg %) and the presence of Type IV hyperlipoproteinemia appear to be the more predominant risk factors. Twenty-nine (62%) of the children had at least one risk factor. Of these, seventeen had two or more risk factors with one subject having as many as five factors.
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Theoretical justification for the preferential use of casing (circumference) measurements for estimating total body volume (TBV) and body density (Db) was studied in 24 female subjects (mean age 20 yr, mean wt 58 kg). Multiple linear regression equations resulted in R = On-0.99 with a standard error no larger than 1.69 liters for predicting TBV and R = Oa-Oh with a standard error no larger than 0.0084 g/ml for predicting Db. Validations of these regression equations using two additional samples of subjects resulted in validity coefficients of r = 0 -0.99. All the correlation coefficients were statistically significant (P less than 0.01).
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To determine the role of endogenous opioid peptides in regulating pulsatile luteinizing hormone (LH) release in the early follicular phase of the menstrual cycle of eumenorrheic women, we evaluated serum LH concentrations in blood collected every 10 min for 12 h in 27 women each studied during two menstrual cycles: (1) without pretreatment and (2) following oral administration of naltrexone, a mu opiate receptor blocking agent, at a dose of 1.0 mg/kg. Pulsatile LH release was assessed by the CLUSTER algorithm. The mean (+/- SE) integrated serum LH concentration (IU/L/min) increased following the administration of naltrexone (4715 +/- 298) in comparison to the control day (3997 +/- 381; p = 0.0008). The mean number of LH pulses (/12 h) detected on the naltrexone day (10.3 +/- 0.3) was higher than on the control day (8.9 +/- 0.4; p = 0.0068). Mean maximal LH peak height (IU/L) was greater on the naltrexone (7.8 +/- 0.5) vs control (6.7 +/- 0.5) days (p = 0.0064) as was the interpulse valley mean serum LH concentration (IU/L; 6.3 +/- 0.4 vs 5.0 +/- 0.4; p = 0.0013). No difference was noted in the mean incremental LH pulse amplitude (IU/L; 1.9 +/- 0.1 vs 2.1 +/- 0.1; p = 0.13), or peak duration (min; 40 +/- 1.8 vs 45.0 +/- 2.4; p = 0.06). Mean LH peak area (IU/L/min) was greater on the control (45.0 +/- 2.4) vs naltrexone (40 +/- 1.8) days (p = 0.0475).(ABSTRACT TRUNCATED AT 250 WORDS)
This study examined the safety of one type of strength training for prepubescent males. Eighteen males (average age, 8.3 +/- 1.2 years) participated in a 45 min/session, three session/week, 14 week supervised strength training program with an attendance rate of 91.5%. Concentric work was done almost exclusively. KinCom analysis showed significant strength gain in this group (P less than 0.05), while an age, sex, and activity matched control group did not gain strength. Safety was evaluated by injury surveillance, blood pressure and heart rate monitoring, scintigraphy, and creatine phosphokinase measurement. Effects on growth and development, flexibility, and motor performance were also investigated, as these are factors with an impact on sports injury occurrence. Results showed that in the short term, supervised concentric strength training results in a low injury rate and does not adversely affect bone, muscle, or epiphyses; nor does it adversely affect growth, development, flexibility, or motor performance. As the safety question is multifaceted, this should not lead to the conclusion that strength training for prepubescents is uniformly safe. Further research is needed.