Acute Cross-education Effect on Force Production and Central/Peripheral Responses to Unilateral Eccentric and Concentric Resistance Exercise in Elbow Flexors
Résumé
The cross-education effect (CE) is the transference of neuromuscular adaptations from a single exercised limb to the contralateral non-exercised limb, which seems to differ between exercise modalities. We compared the acute CE of unilateral eccentric (ECC) and concentric (CONC) resistance exercises on neuromuscular function and force production changes of the non-exercised elbow flexors (EF). Healthy men were randomly allocated into ECC (n=15) or CONC (n=15) groups. The effects of control (CTRLCONC or CTRLECC: 30 min of sitting) and exercise conditions (5 sets x 10 repetitions at 80% of either ECC or CONC 1-repetition maximum) of the dominant EF were measured. Maximal voluntary isometric contraction (MVIC), rate of torque development (RTD), corticospinal excitability (CSE), voluntary activation (VA), and peripheral factors were measured before and immediately after CTRLCONC/CTRLECC or CONC/ECC. Surface electromyography amplitude integral (sEMGi) from the biceps brachii (BB) muscle was monitored during exercise. Physical-mental demands (NASA-TLX) were assessed after exercise. ECC performed 26.2% greater exercise volume than CONC (P=0.01). ECC showed lesser BB sEMGi (P=0.04) than CONC in the exercised EF; however, it induced threefold greater irradiated sEMGi to the non-exercised BB than CONC (P=0.04) during exercise. NASA-TLX was unchanged (P=0.81). The non-exercised EF maintained MVIC, VA, CSP, and peripheral factors after ECC and CONC (P>0.05), but lower RTD was observed after ECC (23.5-29.4%; P<0.05) and CONC (10.8%; P<0.05). Lower CSE at 75% of MVIC occurred after ECC (-17%; P=0.02) compared to CTRLECC, which was correlated to RTD decreases (r=0.45-0.56, P=0.02-0.04). ECC induces acute contralateral reductions in CSE that are associated with decreases in RTD.
Unilateral eccentric and concentric resistance exercises can modulate the neuromuscular response differently, which influences the transference of the force production capacity to the contralateral non-exercised muscle. Unilateral eccentric exercise induced decreases in corticospinal excitability with associated reductions in the early phase of the rate of torque development, which differs from the changes observed after concentric exercise. Thus, both exercise modalities seem to change the excitability differently.
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Est documentée par 10.60483/UNAB/WZCIFD/MGDQGY Jeu de données Penailillo, L. (2025). SUPPLEMENTARY MATERIAL Table 2 docx [Data set]. Repositorio de Datos de Investigación - Universidad Andrés Bello (Chile). https://doi.org/10.60483/UNAB/WZCIFD/MGDQGY
Table 2: Results of the fatigability of the neuromuscular protocol
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Est documentée par 10.60483/UNAB/WZCIFD/QD0I1G Jeu de données Penailillo, L. (2025). SUPPLEMENTARY MATERIAL Table 3 docx [Data set]. Repositorio de Datos de Investigación - Universidad Andrés Bello (Chile). https://doi.org/10.60483/UNAB/WZCIFD/QD0I1G
Table 3: Pre- and Post- (mean ± SD) measurements