Cycling Efficiency and Energy Cost of Walking in Young and Older Adults

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Journal of Applied Psychology






To determine whether age affects cycling efficiency and the energy cost of walking (Cw), 190 healthy adults, ages 18–81 yr, cycled on an ergometer at 50 W and walked on a treadmill at 1.34 m/s. Ventilation and gas exchange at rest and during exercise were used to calculate net Cw and net efficiency of cycling. Compared with the 18–40 yr age group (2.17 ± 0.33 J·kg−1·m−1), net Cw was not different in the 60–64 yr (2.20 ± 0.40 J·kg−1·m−1) and 65–69 yr (2.20 ± 0.28 J·kg−1·m−1) age groups, but was significantly (P < 0.03) higher in the ≥70 yr (2.37 ± 0.33 J·kg−1·m−1) age group. For subjects >60 yr, net Cw was significantly correlated with age (R2 = 0.123; P = 0.002). Cycling net efficiency was not different between 18–40 yr (23.5 ± 2.9%), 60–64 yr (24.5 ± 3.6%), 65–69 yr (23.3 ± 3.6%) and ≥70 yr (24.7 ± 2.7%) age groups. Repeat tests on a subset of subjects (walking, n = 43; cycling, n = 37) demonstrated high test-retest reliability [intraclass correlation coefficients (ICC), 0.74–0.86] for all energy outcome measures except cycling net energy expenditure (ICC = 0.54) and net efficiency (ICC = 0.50). Coefficients of variation for all variables ranged from 3.1 to 7.7%. Considerable individual variation in Cw and efficiency was evident, with a ~2-fold difference between the least and most economical/efficient subjects. We conclude that, between 18 and 81 yr, net Cw was only higher for ages ≥70 yr, and that cycling net efficiency was not different across age groups.


Gross efficiency, Net efficiency, Muscular efficiency, Metabolic cost of walking, Aging



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