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- Genre: Masters Thesis
Description
The effects of aging on muscular efficiency are controversial. Proponents for increased efficiency suggest that age-related changes in muscle enhance efficiency in senescence. Exercise study results are mixed due to varying modalities, ages, and efficiency calculations. The present study attempted to address oxygen uptake, caloric expenditure, walking economy, and gross
et cycling efficiency in young (18-59 years old) and older (60-81 years old) adults (N=444). Walking was performed at three miles per hour by 86 young (mean = 29.60, standard deviation (SD) = 10.50 years old) and 121 older adults (mean = 66.80, SD = 4.50 years old). Cycling at 50 watts (60-70 revolutions per minute) was performed by 116 young (mean= 29.00, SD= 10.00 years old) and 121 older adults (m = 67.10 SD = 4.50 years old). Steady-state sub-maximal gross
et oxygen uptake and caloric expenditures from each activity and rest were analyzed. Net walking economy was represented by net caloric expenditure (kilocalories/kilogram/min). Cycling measures included percent gross
et cycling efficiency (kilo-calorie derived). Linear regressions were used to assess each measure as a function of age. Differences in age group means were assessed using independent t-tests for each modality (alpha = 0.05). No significant differences in mean oxygen uptake nor walking economy were found between young and older walkers (p>0.05). Older adults performing cycle ergometry demonstrated lower gross
et oxygen uptakes and lower gross caloric expenditures (p< 0.05).
et cycling efficiency in young (18-59 years old) and older (60-81 years old) adults (N=444). Walking was performed at three miles per hour by 86 young (mean = 29.60, standard deviation (SD) = 10.50 years old) and 121 older adults (mean = 66.80, SD = 4.50 years old). Cycling at 50 watts (60-70 revolutions per minute) was performed by 116 young (mean= 29.00, SD= 10.00 years old) and 121 older adults (m = 67.10 SD = 4.50 years old). Steady-state sub-maximal gross
et oxygen uptake and caloric expenditures from each activity and rest were analyzed. Net walking economy was represented by net caloric expenditure (kilocalories/kilogram/min). Cycling measures included percent gross
et cycling efficiency (kilo-calorie derived). Linear regressions were used to assess each measure as a function of age. Differences in age group means were assessed using independent t-tests for each modality (alpha = 0.05). No significant differences in mean oxygen uptake nor walking economy were found between young and older walkers (p>0.05). Older adults performing cycle ergometry demonstrated lower gross
et oxygen uptakes and lower gross caloric expenditures (p< 0.05).
ContributorsFlores, Michelle (Author) / Gaesser, Glenn A (Committee member) / Campbell, Kathryn D (Committee member) / Angadi, Siddhartha S (Committee member) / Arizona State University (Publisher)
Created2014
Description
Maximal oxygen uptake (VO2max) declines with age and is a predictor of morbidity and mortality risks. Due to these implications, accurate assessment and determination of VO2max are important for the older population. Without the presence of a VO2 plateau, secondary criteria are used to determine whether the test resulted in a maximal value. However, inconsistent secondary criteria do not account for intersubject variability. To circumvent this issue, a verification phase following a traditional ramp assessment may be utilized. The purpose of this study was to compare verification phase strategies in older adults. A secondary purpose of this study was to examine the repeatability of the ramp assessment performed during each visit. Twenty-two older adults between 60 and 80 years of age were recruited to participate in the study. Each subject completed two experimental trials in a randomized, counterbalanced cross-over design. Both trials consisted of a ramp test and verification phase at either 85% (VP85) or 110% (VP110) of the peak work rate achieved during the ramp (Ramp85 and Ramp110, respectively). Expired gases and heart rate (HR) were monitored continuously and measured every ten seconds. VO2peak was determined by the highest 30-second averages for the ramp and verification phases. No significant differences were observed for absolute (L/min) VO2peak between VP85 (P = 0.679) or VP110 (P = 0.200) and the associated ramp. There was also no significant difference in maximal HR between VP85 (P = 0.243) or VP110 (P = 0.085) and the associated ramp. However, individual data shows that 36% of individuals achieved a 2% greater VO2 (L/min) during the VP85 compared to the Ramp85, while only 15% of subjects achieved a 2% greater VO2 (L/min) during the VP110 compared to Ramp110. No significant differences (P < 0.05) were found for most variables between Ramp1 and Ramp2. These data suggest that if a verification phase is employed for VO2max assessment in otherwise healthy older adults, a power slightly below peak work rate may provide a more accurate assessment compared to a power slightly above peak work rate.
ContributorsVillanueva, Ian Robert (Author) / Dickinson, Jared M (Thesis advisor) / Gaesser, Glenn A (Committee member) / Angadi, Siddhartha S (Committee member) / Arizona State University (Publisher)
Created2019