Contralateral effects of eccentric resistance training on immobilized arm

Abstract

This study compared the effects of contralateral eccentric‐only (ECC) and concentric‐/eccentric‐coupled resistance training (CON‐ECC) of the elbow flexors on immobilized arm. Thirty healthy participants (18‐34 y) were randomly allocated to immobilization only (CTRL; n = 10), immobilization and ECC (n = 10), or immobilization and CON‐ECC group (n = 10). The non‐dominant arms of all participants were immobilized (8 h·day−1) for 4 weeks, during which ECC and CON‐ECC were performed by the dominant (non‐immobilized) arm 3 times a week (3‐6 sets of 10 repetitions per session) with an 80%‐120% and 60%‐90% of one concentric repetition maximum (1‐RM) load, respectively, matching the total training volume. Arm circumference, 1‐RM and maximal voluntary isometric contraction (MVIC) strength, biceps brachii surface electromyogram amplitude (sEMGRMS), rate of force development (RFD), and joint position sense (JPS) were measured for both arms before and after immobilization. CTRL showed decreases (P < .05) in MVIC (−21.7%), sEMGRMS (−35.2%), RFD (−26.0%), 1‐RM (−14.4%), JPS (−87.4%), and arm circumference (−5.1%) of the immobilized arm. These deficits were attenuated or eliminated by ECC and CON‐ECC, with greater effect sizes for ECC than CON‐ECC in MVIC (0.29: +12.1%, vs −0.18: −0.1%) and sEMGRMS (0.31:17.5% vs −0.15: −5.9%). For the trained arm, ECC showed greater effect size for MVIC than CON‐ECC (0.47 vs 0.29), and increased arm circumference (+2.9%), sEMGRMS (+77.9%), and RDF (+31.8%) greater (P < .05) than CON‐ECC (+0.6%, +15.1%, and + 15.8%, respectively). The eccentric‐only resistance training of the contralateral arm was more effective to counteract the negative immobilization effects than the concentric‐eccentric training.

Elbow Joint Angles in Elbow Flexor Unilateral Resistance Exercise Training Determine Its Effects on Muscle Strength and Thickness of Trained and Non-trained Arms

“…The greater increase in the strength in the study by Tseng et al (2020) may be due to the focus on eccentric contractions. Valdes et al (2021) reported that elbow flexor eccentric-only resistance training performed by the dominant (non-immobilized) arm 3 times a week with 80–120% of one concentric 1-RM load increased MVC-ISO strength (20.9%) greater than concentric-eccentric coupled resistance training (13.7%) in which 60–90% of 1-RM load was used for the same total training volume. It seems possible that eccentric-only resistance training is more effective for increasing muscle strength.…”

“…The lack of increase in the other muscle strength measures was probably due to the low intensity of training in the first half of the training period (1–3 sessions) and the lower training volume, as mentioned above. The factors that influence the magnitude of the cross-education effect include training intensity ( Colomer-Poveda et al, 2020 ), muscle contraction type ( Hortobagyi et al, 1997 ; Kidgell et al, 2015 ; Manca et al, 2017 ; Tseng et al, 2020 ; Valdes et al, 2021 ), number of sessions ( Barss et al, 2018 ), and intervention duration ( Manca et al, 2021 ). Some studies have reported that the cross-education effect is greater after eccentric than concentric resistance training ( Hortobagyi et al, 1997 ; Kidgell et al, 2015 ; Tseng et al, 2020 ) or concentric-eccentric coupled training ( Valdes et al, 2021 ).…”

“…The factors that influence the magnitude of the cross-education effect include training intensity ( Colomer-Poveda et al, 2020 ), muscle contraction type ( Hortobagyi et al, 1997 ; Kidgell et al, 2015 ; Manca et al, 2017 ; Tseng et al, 2020 ; Valdes et al, 2021 ), number of sessions ( Barss et al, 2018 ), and intervention duration ( Manca et al, 2021 ). Some studies have reported that the cross-education effect is greater after eccentric than concentric resistance training ( Hortobagyi et al, 1997 ; Kidgell et al, 2015 ; Tseng et al, 2020 ) or concentric-eccentric coupled training ( Valdes et al, 2021 ). This may be attributed to the greater central nervous system adaptations, such as the reduction of intracortical and interhemispheric inhibition after eccentric than concentric resistance training ( Kidgell et al, 2015 ).…”

“…In (Hortobagyi et al, 1997;Kidgell et al, 2015;Manca et al, 2017;Tseng et al, 2020;Valdes et al, 2021), number of sessions (Barss et al, 2018), and intervention duration (Manca et al, 2021). Some studies have reported that the cross-education effect is greater after eccentric than concentric resistance training (Hortobagyi et al, 1997;Kidgell et al, 2015;Tseng et al, 2020) or concentric-eccentric coupled training (Valdes et al, 2021).…”

Cross-education and detraining effects of eccentric vs. concentric resistance training of the elbow flexors

“…This suggest that ET increased MVIC torque of the trained and non-trained arms more similarly than CT. Previous studies have reported a greater cross-education effect on MVIC strength after ET than CT [ 20 , 22 , 31 , 32 ]. For example, Kidgell et al [ 22 ] reported that after 4 weeks of unilateral resistance training of the wrist flexors performed three times a week, the increase in MVIC strength was greater in ET (43 %) than CT (11 %) for the non-trained arm.…”