Efeito da educação cruzada sobre a função muscular durante o destreinamento em mulheres idosas

Abstract

Elderly people are unable to fully recover muscle function with activities return after a period of physical inactivity. Thus, avoiding physical inactivity is an important strategy to prevent loss of muscle function. However, in certain situations, such as musculoskeletal injuries, a part of the body (a leg or arm) is forced (e.g. pain) to physical inactivity (or low physical activity) for recovery. In this sense, the strategy that seems to be the most adequate is cross-training, in which training of a limb promotes adaptations in the untrained contralateral limb, avoiding loss of muscle function of the inactive limb. However, this strategy has not yet been tested in the active elderly. The objective of this study was to verify the effect of four weeks of cross-training on quadriceps function during detraining. We selected 19 elderly women who underwent a 10-week training period previously conducted. These elderly women were randomized to control (CO), n = 8, or cross-transfer (CT), n = 11. A maximal repetition (1RM), strength, torque, power, speed and myoelectric activity after a four-week period of detraining and cross-training in the unilateral extensor chair. Group TC realized unilateral knee extension exercise, with the first week: three sets of ten repetitions with a load of 70% of 1RM, the second week: three sets of eight repetitions with a load of 75% of 1RM, the third week : three sets of eight replicates with 80% loading of 1RM and fourth week: three sets of six replicates with 85% loading of 1RM. After 4 weeks, 1RM, the mean (N) strength in 40% and in 60% of 1RM, mean 40% and 60% of 1RM reduced in both groups (P <0.001), with no interaction between them (P> 0.05). There was a reduction of the torque peak at 60% in the CO group, but not for the TC group (P = 0.044). There was reduction of mean and peak power at 60% in the CO group only (P = 0.003 and P = 0.022, respectively). However, for the peak and average velocity at 60% of 1 RM, the CO group presented reduction, while the TC group presented maintenance (P = 0.039 and P = 0.035, respectively). For the EMG of the 1RM (RMS or peak) test corrected for the EMG of the CIVM (RMS or peak) test, only the TC group showed increase over this variable in the 60% 1RM test (RMS / RMS of the CIVM: P = 0.037 and PEAK / PEAK MIC: P = 0.027). Therefore, the training provided positive responses to the TC group, suggesting that cross-training can avoid the effects of four weeks of detraining on muscle strength and potency in the elderly. In addition, the adaptations seem to be associated to the specificity of training load and neural adaptations verified through myoelectric activity.