RESUMO
CONTEXT: Long-term conditioning programs for enhanced sensorimotor performance have been causally linked to reduced risk of serious ligamentous injury. However, the efficacy of brief, short-term conditioning interventions has not been established. OBJECTIVE: To assess the effects of short-term sensorimotor conditioning on the knee flexors. DESIGN: Randomized controlled trial. SETTING: University research laboratory. PARTICIPANTS: 23 males randomly assigned to conditioning (n = 12; age: 20.5 ± 1.8 y; height: 1.80 ± 0.05 m; body mass: 74.3 ± 6.0 kg [mean ± SD]) and no-conditioning control (n = 11; age: 20.6 ± 1.9 y; height: 1.79 ± 0.05 m; body mass: 73.6 ± 6.3 kg) groups. INTERVENTION: Sensorimotor conditioning of the nondominant leg (4 sessions/wk; 3 wk). MAIN OUTCOME MEASURES: Sensorimotor (blind force and limb-position-replication errors) and neuromuscular (peak force, electromechanical delay [volitional and magnetically evoked]) performance of the knee flexors of both legs were assessed. The contralateral limb and an antecedent period of no conditioning were controls. RESULTS: The conditioned leg showed decreased force error to 3.8% (3.8 ± 6.9% vs 6.3 ± 3.7% [mean ± SD], post- vs preconditioning, respectively; F1,21 = 5.4; P = .04) and a trend toward decreased positional error to 2.0% (2.0 ± 6.9% vs 4.7 ± 7.7%, post- vs preconditioning; F1,21 = 2.7; P = .06). Performances were not altered in the control conditions. Modest improvements were noted for volitional electromechanical delay following conditioning (39.8 ± 4.3 ms vs 42.3 ± 5.2 ms [F1,21 = 7.2; P = .01]), but peak force (overall, 202 ± 78 N) and magnetically evoked electromechanical delay (24.7 ± 4.2 ms) were not influenced. CONCLUSION: Short-term conditioning offered improved sensorimotor performance and positively affected neuromuscular determinants of knee flexor performance in men.
