Cycling training induces adaptive cardiovascular benefits both centrally and peripherally in previously sedentary individuals. Less is known about what exercise prescription is necessary to improve fitness in already active, healthy middle aged adults. Cycling is not a well-accepted exercise to enhance strength, especially in healthy active adults.
PURPOSE: To determine if participation in a novel cycling program affects aerobic fitness (VO2max) and leg strength.
METHODS: Participants (N=41, M+SD age=45.5+8.1) were healthy adults recruited to complete a 6-day/wk exercise program on a cycle ergometer for 6-months. All participants self-reported at least 30 min of vigorous exercise, 3 times/wk prior to joining the study and met NASA developed fitness standards. Participants exercised 6 day/wk, using high intensity routines (SPRINT) developed and designed to protect fitness of middle aged active healthy astronauts. SPRINT includes (a) 30 min continuous aerobic cycling at or above 75% of max heart rate (HRmax), (b) long, 4x4 min intervals at or above 90% HRmax with 3 min active rest, (c) medium 6x2 min intervals at 70, 80, 90, 100, 90, and 80% of HRmax, respectively with 2 min active rest, and (d) short, 30 sec max sprint intervals with 20 sec active rest. Participants reported that they did not change other exercise behavior during the study. VO2max was measured (via indirect calorimetry) pre, mid (3 month), and 6 month post intervention. Isometric leg strength, including peak torque extension (PTE) and flexion (PTF) was measured (pre and 6 month post intervention) on the right leg using the Biodex3 dynamometer. Results were assessed via repeated measures ANOVA.
RESULTS: Average VO2max increased from pre to mid-test (33.8±6.2 ml/kg/min vs. 38.5±6.8 ml/kg/min), and was maintained from mid to post-test (38.5±6.8 ml/kg/min vs. 38.3±7.3 ml/kg/min), F(2,62) = 57.65, p<0.001. PTE increased significantly from pre to post test (119.6±42.6ft/lbs vs. 131.7±48.8ft/lbs), F(1,35)=8.00, p<0.008. PTF did not change from pre to post-test (71.2±21.4ft/lbs vs. 70.2±21.7ft/lbs), F(1,35)=0.13, p=0.73.
CONCLUSION: SPRINT interval cycle ergometer training is effective for increasing aerobic fitness and muscular strength over a 6-month training period among physically active middle-age adults.
Grant: NASA/NSBRI MA03401.