| PURPOSE: To assess the individual variability in the capacity to lift submaximal loads in younger and older men and women in resistance training exercises.;METHODS: We recruited 16 younger (8 female, 22.8+/-1.8 yrs) and 32 older adults (16 female, 74.3+/-5.4 yrs). One repetition maximum (1RM) was measured on two days for all participants using three different exercises: leg press (LP), leg extension (LE), bicep curl (BC). On days three and four, participants performed repetitions to failure at 60% or 80% 1RM, the order of which was randomized.;RESULTS: For LP, LE, and BC, at 60% 1RM, younger men completed 26.3 (95% CI=12.9-39.6), 13.9 (10.7-17.1) and 12.9 (10.0-15.8) repetitions and younger women completed 28.8 (22.0-35.5), 11.4 (9.7-13.1), and 13.0 (9.8-16.2). At 60%1RM, older men completed 19.3 (14.7-23.8), 11.8 (10.2-13.3), and 14.3 (11.8-16.8) and older women completed 23.3(14.8-31.7), 11.1 (9.0-13.3), and 16.1 (12.4-21.4) repetitions. For LP, LE, and BC, at 80% 1RM, younger men completed 14.9 (8.7-21.0), 7.3 (5.8-8.7), 6.1 (5.0-7.3) and younger women completed 17.0 (12.2-21.8), 8.8 (7.3-10.2), and 6.5 (4.2-8.8). At 80% 1RM older men completed 9.1 (7.2-11.0), 8.6 (7.2-9.9), 6.1 (4.5-7.6) and older women completed 12.8 (8.7-16.8), 7.9 (6.1-9.6), 8.9 (6.7-11.2). Greater muscular strength was observed in younger participants on all tasks (p<0.01).;CONCLUSIONS: We observed considerable inter-individual variability in the number of repetitions completed in younger and older men and women at 60% and 80 % 1RM. Practitioners should give consideration to individual variability when attempting to maximize the benefits of resistance exercise.;Supported by a Science Research Fund grant at Wake Forest University. |
