Effects Of Aerobic Training Programs On Maximal Joint Torque And Muscular Endurance In Senior Women

Abstract

PURPOSE To compare the effectiveness of aerobic exercise programs based on two training modes: intermittent vs continuous and two types of activity: walking and stepups, on maximal joint torque and muscular endurance, in 135 community-dwelling women aged 55–77. METHODS A 42-week prospective study with assessments at baseline (T0), after a 12-week exercise program (1 session/week) (T1), and 30 weeks after the program (T2), was investigated. Individuals were randomly assigned to one of five groups depending on the training program: continuous walking (near 80% maximal heart rate (HRmax)) (n = 43; 65.7 ± 5.0 yr), intermittent walking (near HRmax) (n = 44; 65.9 ± 3.8 yr), continuous step-ups (near 80% HRmax) (n = 23; 64.5 ± 4.0 yr), intermittent step-ups (near HRmax) (n = 13; 64.8 ± 2.9 yr) and control (n = 12; 65.6 ± 4.3 yr). Fat-free thigh volume (FFV) was estimated by anthropometric measurements. Maximal joint torque (MJT) of lower-limbs extensors was assessed with a force transducer. Muscular endurance (ME) was expressed as percentages of joint torque decrease during two exercises of 60 sec: a maximal continuous contraction and repeated maximal contractions of 2 sec separated by 3 sec of relaxation. RESULTS At T0, no significant difference was observed between the five studied groups. MJT was poorly related to FFV (r2<0.07, p<0.05). MJT of right lower-limb was significantly greater than MJT of left lower-limb (p<0.001). No significant MJT and ME improvement was observed from T0 to T2. CONCLUSION Whatever training mode and type of activity, aerobic exercise programs did not lead any maximal joint torque and muscular endurance improvements. The small number o training sessions and the non specificity (compared with musculation) of the exercise programs could explain these results. Supported by the FFEPGV (French Federation of Physical Education and Voluntary Gymnastics), the Auvergne DRJS (Regional Direction of Youth and Sports), the AFRAPS (French Association for Research in Physical and Sportive Activity), and the CREAS (Auvergne Executive Committee for Health Actions).