Multidimensional Predictive Modeling to Understand Mechanisms of Exercise Response Heterogeneity in Older Adults (M3AX)

ET will consist of 3x/wk training (MWF) with MF being steady state cycling, treadmill, or elliptical at 70-75% HRR for 30 min and the W session being a 20 min high intensity interval session on a cycle ergometer (1 min on/off; 10 cycles) targeting 85-90% HRR. The treadmill and elliptical on M or F will be provided for variety but the mainstay will be cycle ergometry. On MF participants will complete 3 sets x 8-12 repetitions for leg press, knee extension, hamstring curl, chest press, seated row, overhead press, lat pulldown, triceps push-down, and biceps curl in superset fashion \[i.e., alternate between opposing muscle groups without rest (chest press followed by seated row)\] with a 60 s rest between supersets. Sets will be performed with load progression to ensure volitional fatigue in the 8-12 rep range. Core exercises (trunk flexion and extension) will also be included using bodyweight only for 3 sets.