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

Abstract

Background Unilateral resistance training increases the strength of the contralateral non-trained homologous muscles known as the cross-education effect. We tested the hypothesis that unilateral eccentric resistance training (ET) would induce greater and longer-lasting cross-education effect when compared with concentric resistance training (CT). Methods Young (20–23 y) participants were allocated to ET (5 males, 4 females) or CT (5 males, 4 females) group that performed unilateral progressive ET or CT of the elbow flexors, twice a week for 5 weeks (10 sessions) followed by a 5-week detraining, and control group (7 males, 6 females) that did not perform any training. Maximum voluntary isometric contraction torque of the elbow flexors (MVIC), one-repetition maximum of concentric dumbbell curl (1-RM), and biceps brachii and brachialis muscle thickness (MT) were measured from the trained and non-trained arms before, several days after the last training session, and 5 weeks later. A ratio between the trained and non-trained arms for the change in MVIC or 1-RM from pre- to post-training (cross-body transfer ratio) was compared between ET and CT groups. Results The control group did not show significant changes in any variables. Both ET and CT increased (P < 0.05) MVIC (22.5 ± 12.3 % vs. 26.0 ± 11.9 %) and 1-RM (28.8 ± 6.6 % vs. 35.4 ± 12.9 %) of the trained arm without a significant difference between groups. MVIC was maintained after detraining for ET but returned to the baseline for CT, and 1-RM was maintained after detraining for both ET and CT. For the non-trained arm, MVIC (22.7 ± 17.9 % vs. 12.2 ± 10.2 %) and 1-RM (19.9 ± 14.6 % vs. 24.0 ± 10.6 %) increased similarly (P > 0.05) after ET and CT, and MVIC returned to the baseline after detraining, but 1-RM was maintained for both groups. An increase (P < 0.05) in MT was found only after ET for the trained arm (7.1 ± 6.1 %). The cross-body transfer ratio for MVIC was greater (P < 0.05) for ET (90.9 ± 46.7 %) than CT (49.0 ± 30.0 %). Conclusions These results did not support the hypothesis and showed similar changes in the most of the variables between ET and CT for the trained and non-trained arms, and strong cross-education effects on MVIC and 1-RM, but less detraining effect after ET than CT on MVIC of the trained arm. Trial registration University Hospital Medical Information Network Clinical Trials Registry (UMIN000044477; Jun 09, 2021).

Relationship between Eccentric-Exercise-Induced Loss in Muscle Function to Muscle Soreness and Tissue Hardness

“…This study showed that the decrease in ROM caused by ECC exercise was associated with an increase in tissue hardness, and the decrease in muscle strength was associated with muscle soreness. As described above, the ECC emphasized a larger muscle strength increase and muscle hypertrophy when compared with other types of training [ 3 , 4 , 5 ]. Nevertheless, acutely and up to the time that the muscle is fully recovered, ECC exercise could negatively affect athletic performance, reduce training quality, adherence to resistance, and likely cause higher injury prevalence.…”

“…The time course of changes in muscle strength ROM, DOMS, swelling, and blood creatine kinase (CK) in the day after intense eccentric exercise varies, and the loss of muscle strength and ROM and increase in muscle soreness could peak 24–48 h after intense ECC exercise [ 1 ]. Additionally, the ECC emphasized that resistance training could cause larger muscle-strength increase and muscle hypertrophy [ 3 , 4 , 5 ]. Since such impairments after intense ECC exercise could influence athletic performance, reduce training quality, reduce adherence to resistance training, and result in a higher injury prevalence, it is necessary to control the loss of muscle strength and ROM and increase muscle soreness after intense ECC exercise.…”

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

“…A familiarization session was set 1 week prior to the baseline measurements, and all participants practiced the MVC-ISO, MVC-CON, and MVC-ECC torque measurements on both trained (dominant) and non-trained (non-dominant) arms. The resistance training was performed twice a week with a rest period of at least 48 h between sessions for 5 weeks ( Sato et al, 2021 ). All participants were instructed to refrain from any systematic training outside the study for the experimental period.…”

“…Each participant lay in the supine position on a bed with the arms placed at each side and the forearm supinated while relaxing the arms. Ultrasound measurements of the transverse-axis were repeated twice, and the MT of biceps brachii plus brachialis was measured as the distance from the inner edge of the fascia to the humerus ( Abe et al, 2000 ; Sato et al, 2021 ). The average of the two measurements was calculated for each site and used for further analysis.…”

Comparison of the Acute Effects of Foam Rolling with High and Low Vibration Frequencies on Eccentrically Damaged Muscle

“…Many factors affect muscle strength and hypertrophy in resistance training. Although further discussion is needed regarding the effect of muscle contraction mode, it is well known that resistance training emphasizing eccentric contraction (ECC) has a superior effect on muscle strength and hypertrophy than resistance training emphasizing concentric contraction (Katsura et al, 2019;Sato et al, 2021;Tseng et al, 2020). Although ECC resistance training can be applied in sports and medical fields, delayed onset muscle soreness (DOMS) often occurs as an adverse effect.…”