Gregory A. Brown

COMPARISON OF ENERGY EXPENDITURE ON A TREADMILL VS. AN ELLIPTICAL DEVICE AT A SELF-SELECTED EXERCISE INTENSITY

Brown, GA, Cook, CM, Krueger, RD, and Heelan, KA. Comparison of energy expenditure on a treadmill vs. an elliptical device at a self-selected exercise intensity. J Strength Cond Res 24(6): 1643-1649, 2010-Treadmills (TM) and elliptical devices (EL) are popular forms of exercise equipment. The differences in the training stimulus presented by TM or EL are unknown. The purpose of this investigation was to evaluate oxygen consumption, energy expenditure, and heart rate on a TM or EL when persons exercise at the same perceived level of exertion. After measuring peak oxygen uptake (&OV0312;O2peak) in 9 male and 9 female untrained college-aged participants, the subjects performed 2 separate 15-minute submaximal exercise tests on the TM and EL at a rating of perceived exertion (RPE) of 12-13. &OV0312;O2peak was higher (p < 0.05) in the males (48.6 ± 1.5 vs. 45.2 ± 1.6 ml/kg/min) than the females (41.7 ± 1.8 vs. 38.8 ± 2.2 ml/kg/min) for both TM and EL (means ± standard error of the mean; for TM vs. EL respectively), but there were no differences in the measured &OV0312;O2peak between TM or EL. During submaximal exercise there were no differences in RPE between TM and EL. Total oxygen consumption was higher (p < 0.05) in males (30.8 ± 2.2 vs. 34.9 ± 2.2 L) than females (24.1 ± 1.8 vs. 26.9 ± 1.7 L) but did not differ between TM and EL. Energy expenditure was not different between TM (569 ± 110 J) or EL (636 ± 120 kJ). Heart rate was higher (p < 0.05) on the EL (164 ± 16 beats/min) compared to the TM (145 ± 15 beats/min). When subjects exercise at the same RPE on TM or EL, oxygen consumption and energy expenditure are similar in spite of a higher heart rate on the EL. These data indicate that during cross training or noncompetition-specific exercise, an elliptical device is an acceptable alternative to a treadmill.

Validity of HydraTrend Reagent Strips for the Assessment of Hydration Status

Abstract Abbey, BM, Heelan, KA, Brown, GA, and Bartee, RT. Validity of HydraTrend reagent strips for the assessment of hydration status. J Strength Cond Res 28(9): 2634–2639, 2014—Hydration is used by athletic governing organizations for weight class eligibility. The measurement of urine specific gravity (USG) as a measure of hydration by reagent strips is a controversial issue. The purpose of this study was to determine the validity of HydraTrend reagent strips that facilitate the correction of USG for alkaline urine samples against refractometry for the assessment of USG. Fifty-one participants (33 males, age = 22.3 ± 1.3 years; 18 females, age = 22.4 ± 1.2 years) provided 84 urine samples. The samples were tested for USG using refractometry and reagent strips and for pH using reagent strips and a digital pH meter. Strong correlation coefficients were found between refractometry and reagent strips for USG (rs(82) = 0.812, p < 0.01) and between reagent strips and pH meter for pH (rs(82) = 0.939, p < 0.01). It was observed that false negative results for National Collegiate Athletic Association (NCAA) requirements (fail refractometry with USG >1.020, pass reagent strips with USG ⩽1.020) occurred 39% (33/84) of the time and false negative results for National Federation of State High School Association (NFHS) requirements (fail refractometry with USG >1.025, pass reagent strips with USG ⩽1.025) occurred 14% (12/84) of the time. There were no false positives (pass refractometry and fail reagent strips) for NCAA or NFHS requirements. These data show that refractometry and reagent strips have strong positive correlations. However, the risk of a false negative result leading to incorrect certification of euhydration status outweighs the benefits of the HydraTrend reagent strips for the measurement of USG.

A fitness screening model for increasing fitness assessment and research experiences in undergraduate exercise science students

When students analyze and present original data they have collected, and hence have a cultivated sense of curiosity about the data, student learning is enhanced. It is often difficult to provide students an opportunity to practice their skills, use their knowledge, and gain research experiences during a typical course laboratory. This article describes a model of an out-of-classroom experience during which undergraduate exercise science students provide a free health and fitness screening to the campus community. Although some evidence of the effectiveness of this experience is presented, this is not a detailed evaluation of either the service or learning benefits of the fitness screening. Working in small learning groups in the classroom, students develop hypotheses about the health and fitness of the population to be screened. Then, as part of the health and fitness screening, participants are evaluated for muscular strength, aerobic fitness, body composition, blood pressure, physical activity, and blood cholesterol levels. Students then analyze the data collected during the screening, accept or reject their hypotheses based on statistical analyses of the data, and make in-class presentations of their findings. This learning experience has been used successfully to illustrate the levels of obesity, hypercholesterolemia, and lack of physical fitness in the campus community as well as provide an opportunity for students to use statistical procedures to analyze data. It has also provided students with an opportunity to practice fitness assessment and interpersonal skills that will enhance their future careers.

Economy of Jogging Stroller use During Running

BACKGROUND: Three-wheeled baby strollers for use during jogging/running (JS) have been available for almost twenty years and are widely used. Although one can easily assume that using a JS will change the energy cost and stride mechanics of running, no information regarding the change is available. PURPOSE: To determine the impact of using a JS on the oxygen cost and stride length/frequency of running. METHODS: 8 experienced runners (5 female, 21.1 ± 1.7 y, 20.8 ± 1.9 % fat, VO2peak 47.8 ± 2.4 ml/kg/min; 3 male 21.7 ± 1.5 y, 8.4 ± 4.2 % fat, VO2peak 50.1 ± 6.1 ml/kg/min) completed a supervised, self-paced 2.4 km running trial while pushing (JS) or not pushing (CON) a JS. To simulate the weight of a child, a 9 kg weight was fastened to the seat of the jogging stroller. VO2 and HR were measured on a breath by breath basis with a portable metabolic cart, then the data were averaged over 30 second intervals with a custom computer algorithm. Number of steps taken was measured with a pedometer. Data were analyzed using paired t-tests with a Bonferoni correction of alpha level for repeated tests. Data are presented as Means ± se. RESULTS: Time to complete the run was not different between JS and CON (687 ± 30 vs. 660 ± 18 seconds), respectively. Mean steady state HR (173.0 ± 5.0 vs. 167.0 ± 5.1 beats/min) and VO2 (40.1 ± 3.1 vs. 36.1 ± 2.8 ml/kg/min) were higher (PCONCLUSION: Using a jogging stroller results in significant, yet relatively minor, increases in HR and decreases running economy due partly to changes in the normal stride pattern. ©2004The American College of Sports Medicine Keywords: Exercise; Jogging; Baby strollers; Annual Meeting Abstracts: F-23 1714 Language: en