2011 Annual Conference

Newstead, Ann H.

The purpose of this study was to determine the effects of an 8-week intervention program, either cycling or walking, on measures of function and maximal power in sedentary older adults.

A sample of sedentary older adults ages 65-74 (n=6; 3 per group) were recruited from the community. The inclusion criteria were: 1) ability to walk 1-mile by self-report, 2) physician clearance, 3) ability to provide informed consent, and 4) meet the definition of sedentary. In this study “sedentary” was defined as someone who spent more than 60% of their day in less energy consuming activities as measured by the Actical ®.

The intervention study was a repeated-measures within-subjects design with a between-group comparison. There was a baseline pre-test (-3 to 0 weeks), intervention (8 weeks), and post-test phase (week 9). Sedentary older adults were randomly assigned into two different groups: a “cycling” intervention group or a “walking” intervention group. The “cyclists” focused on intermittent fast and moderate, low intensity power training whereas the “walkers” focused on intermittent fast and moderate walking on a treadmill. Both exercise groups met 3 times a week for 30 minutes of exercise for a total of 8 weeks. Outcome measures included power and functional measures (Five time Sit to stand [5STS], Timed Up and Go [TUG], Timed Stair Climb [TSC]). Maximal power (P_max) was measured using specialized cycle ergometer. Heart rate, blood pressure, and perceived exertion were monitored for safety.

Mean and standard deviation (SD) were computed for each group. The Coefficient of Variation ([CV = (T₂ – T₁)/T₁]) was used to determine percent change. The Coefficients of Determination (R²) between power and timed tests were also calculated to show the relationship between the outcome measures.

The cycling group improved Pmax over 8 weeks by 7.1% from pre test (mean + SD; 5.99 + 2.20 w/kg) to post test  (6.42 + 1.27 w/kg). In comparison, the walking group improved Pmax by 0.6% (pre test  6.91 + 1.88 w/kg; post test  7.03 + 1.27 w/kg). For 5STS, the cycling group improved 7.1% (pre-test  8.25 + 2.20 s; post test  7.94 + 2.63 s), whereas the walking group decreased performance by 15% (pre test  6.69 + 0.91 s;  post test 7.15 + 1.87s). For the TUG, the cycling group improved 6% (pre-test 7.16 + 1.09 s; post test 6.94 + 1.98 s), and the walking group improved by 3% (pre test  6.65 + 1.09; post test 6.98 + 1.52 s). Both groups improved the TSC - the cycling group improved by 11% (pre-test  0.9 + 3.19 s/step; post test 0 0.83 + 0.15), and the walking group improved by 16% (pre test 0.78 + .20; post test 0.66 + 0.10). Moderate to high correlations were found between power and 5STS (R2 = .615 for pre test, and R2 = .762 for post test), between power and TUG (R2 = .533 for pre test, and R2 = .750 for post test) and between power and TSC (R2 = .785 for pre test, and R2 = .820 for post test) for the groups combined.

Cycling improved performance on power tasks more so than walking, as the cycling group improved on all timed functional tests as well as power. A comparison of pre and post testing showed that there were more meaningful changes (>5%) in the cycling group for 1) 5STS, 2) TUG, whereas TSC improvements were greatest for the walking group. All functional tests were found to have a positive correlation with power. The largest positive correlation was between power and Timed Stair Climb. Our preliminary results need further study, a larger participant pool and comparison with a control group is in progress.

Cycling may be a more effective than walking as a mode of exercise to improve leg power production. Both modes of exercise, cycling and walking, improved overall power and functional task performance. Older adults who are sedentary will benefit from regular exercise. Health professionals are encouraged to provide exercise prescriptions for their patients.