expenditure during the present study. The four sensors were embedded under the insole at the heel, arch, ball, and toe positions. (b) A depiction of the instrumented treadmill and general experimental setup. Methods Subjects Thirty adults participated in this study. To be included, each subject was required
Alyssa Evans, Gavin Q. Collins, Parker G. Rosquist, Noelle J. Tuttle, Steven J. Morrin, James B. Tracy, A. Jake Merrell, William F. Christensen, David T. Fullwood, Anton E. Bowden and Matthew K. Seeley
Claire Peel, Carolyn Utsey and Jan MacGregor
This study aimed to evaluate the effects of an 8-week supervised exercise program on physiological measurements during treadmill walking, muscle strength, functional performance, and health status in older adults limited in physical function. Twenty-four participants were randomly assigned to an exercise group (EG, N = 13) or a control group (CG, N = 11), and were evaluated before and after the exercise program (EG) or 8-week period (CG). Evaluations included a progressive treadmill lest, strength testing, the Physical Performance Test (PPT), and the SF-36 Health Survey. The exercise program consisted of 3 sessions per week of brisk walking and strengthening exercises. The EG demonstrated increases in cardiorespiratory fitness and increases in treadmill walking time. The EG also demonstrated increases in force production in 3 of the 6 muscle groups that were tested. Both the EG and CG demonstrated improvements in PPT scores and in 2 health concepts on the SF-36 Health Survey.
David Alexander Leaf and Holden MacRae
The purpose of this study was to examine the criterion-related validity of two indirect measures of energy expenditure (EE): American College of Sports Medicine (ACSM) predictive equations, and estimated EE based on the Caltrac accelerometer. These measures were compared in 20 community-dwelling older men and women (mean age 71 years). The strength of the relationships among major determinants of EE during self-selected speeds of treadmill and outdoor walking was also examined. EE measured by respiratory gas analysis during an exercise stress test was highly correlated with ACSM predictive equations and poorly correlated with Caltrac. Multivariate regression equations were established to evaluate the ability of independent variables—body weight and height, age, and preferred treadmill walking speed—to predict EE (dependent variable). It was concluded that the ACSM predictive equations are suitable for use in elderly individuals, and that the apparent differences in the relationships between treadmill and outdoor walking speeds on EE deserve further investigation.
Richard A. Boileau, Edward McAuley, Demetra Demetriou, Naveen K. Devabhaktuni, Gregory L. Dykstra, Jeffery Katula, Jane Nelson, Angelo Pascale, Melissa Pena and Heidi-Mai Talbot
A trial was conducted to examine the effect of moderate aerobic exercise training (AET) on cardiorespiratory (CR) fitness. Previously sedentary participants, age 60-75 years, were randomly assigned to either AET treatment or a control group for 6 months. The AET consisted of walking for 40 min three times/week at an intensity that elevated heart rate to 65% of maximum heart rate reserve. The control group performed a supervised stretching program for 40 min three times/week. CR fitness was assessed before and after the treatments during a grade-incremented treadmill walking test. Both absolute and relative peak V̇O2 significantly increased (p < .01) in the AET group, whereas they decreased modestly in the control group. Maximum treadmill time increased significantly (p < .01) in the AET group relative to the control group. These results indicate that CR fitness as measured by peak V̇O2 modestly improves in the elderly with a moderate-intensity, relatively long-term aerobic exercise program.
Blanche Evans, David Hopkins and Tracey Toney
The purpose of this study was to determine the metabolic stress of a self-paced half-mile walk test incorporated in the AAHPERD functional fitness assessment for older adults. Forty-three subjects, aged 57 to 75, completed a half-mile walk on an indoor track (IT) and during a treadmill simulation (TS) of the track walk. Treadmill data indicated that subjects exercised at a mean VO2 of 14.7 ml · kg−1 · min−1 and mean heart rate (b · min−1) of 129. A significant difference (p ≤ .05) was found between IT and TS on rating of perceived exertion. Results indicate that older subjects selected a pace that stressed their cardiorespiratory system without producing severe fatigue or medical complications. Therefore, the half-mile walk test appears to be a safe test that may be incorporated in functional fitness testing. However, its ability to determine functional capacity needs further study.
Walter J. Rejeski and Paul M. Ribisl
The purpose of this study was to examine the effects of anticipated task duration on ratings of perceived exertion during treadmill running. Male subjects.(N = 15) completed two separate runs on a motor-driven treadmill at 85% V02 max. During one trial, subjects ran for a period of 20 minutes, while for a second trial, subjects were led to believe that they would be running for 30 minutes. In each case, the trials were terminated at the 20-minute mark. Ratings of perceived exertion, heart rates, respiratory rates, and ventilatory minute volumes were collected across each trial. Results supported the supposition that the anticipation of continued performance mediated ratings of effort expenditure. This effect was obtained only during moderate work levels and was in contrast to research examining mental fatigue.
Joanne Kraenzle Schneider and Kenneth H. Pitetti
The purpose of this study was to compare measured
Amanda Hickey, Dinesh John, Jeffer E. Sasaki, Marianna Mavilia and Patty Freedson
There is a need to examine step-counting accuracy of activity monitors during different types of movements. The purpose of this study was to compare activity monitor and manually counted steps during treadmill and simulated free-living activities and to compare the activity monitor steps to the StepWatch (SW) in a natural setting.
Fifteen participants performed laboratory-based treadmill (2.4, 4.8, 7.2 and 9.7 km/h) and simulated free-living activities (eg, cleaning room) while wearing an activPAL, Omron HJ720-ITC, Yamax Digi-Walker SW-200, 2 ActiGraph GT3Xs (1 in “low-frequency extension” [AGLFE] and 1 in “normal-frequency” mode), an ActiGraph 7164, and a SW. Participants also wore monitors for 1-day in their free-living environment. Linear mixed models identified differences between activity monitor steps and the criterion in the laboratory/free-living settings.
Most monitors performed poorly during treadmill walking at 2.4 km/h. Cleaning a room had the largest errors of all simulated free-living activities. The accuracy was highest for forward/rhythmic movements for all monitors. In the free-living environment, the AGLFE had the largest discrepancy with the SW.
This study highlights the need to verify step-counting accuracy of activity monitors with activities that include different movement types/directions. This is important to understand the origin of errors in step-counting during free-living conditions.
Carmelo Bazzano, Lee N. Cunningham, Giovanni Cama and Tony Falconio
The purpose of this study was to examine the relationship between selected physiological variables and lactate accumulation at the end of a l-mile walk test (MWT) in older women (mean ± SD: 64.6 ± 3.1 years). Seventeen women with a
Mallory R. Marshall and James M. Pivarnik
Maternal physical activity declines across gestation, possibly due to changing perception of physical activity intensity. Our purpose was to a) determine whether rating of perceived exertion (RPE) during a treadmill exercise changes at a given energy expenditure, and b) identify the influence of prepregnancy physical activity behavior on this relationship.
Fifty-one subjects were classified as either exercisers (N = 26) or sedentary (N = 25). Participants visited our laboratory at 20 and 32 weeks gestation and at 12 weeks postpartum. At each visit, women performed 5 minutes of moderate and vigorous treadmill exercise; speed was self-selected. Heart rate (HR), oxygen consumption (VO2), and RPE were measured during the last minute at each treadmill intensity.
At moderate intensity, postpartum VO2 was higher compared with 20- or 32-week VO2, but there was no difference for HR or RPE. For vigorous intensity, postpartum HR and VO2 were higher than at 32 weeks, but RPE was not different at any time points.
RPE does not differ by pregnancy time point at either moderate or vigorous intensity. However, relative to energy cost, physical activity was perceived to be more difficult at 32 weeks compared with other time points. Pregnant women, then, may compensate for physiological changes during gestation by decreasing walking/running speeds.