elbow flexion

ABSTRACT: Shibata, K, Yamaguchi, T, Takizawa, K, and Nosaka, K. Comparison between eccentric-concentric and eccentric-only dumbbell arm curl exercise training for their effects on neuromuscular adaptations. J Strength Cond Res XX(X): 000-000, 2026-Eccentric-concentric (ECC-CON), low-load (ECC-Low), and high-load eccentric-only (ECC-High) dumbbell arm-curl exercise training were compared to test the hypothesis that ECC-Low would induce similar neuromuscular adaptations to ECC-CON and ECC-High. Thirty-four male university students without regular elbow flexor resistance exercise training were placed to ECC-CON (n = 11), ECC-Low (n = 11), or ECC-High (n = 12) group, and trained twice weekly for 6 weeks. The training load was progressively increased from 30 to 90% of concentric-only one-repetition maximum (CON1-RM) for ECC-CON and ECC-Low, and of eccentric-only 1-RM (ECC1-RM) for ECC-High. Rating of perceived exertion (RPE) was recorded after each set and averaged RPE was obtained. Changes in elbow flexion CON1-RM and ECC1-RM, maximal voluntary isometric contraction (MVIC) strength at 30°, 60°, and 90° elbow flexion, concentric peak power at 30% MVIC, and biceps brachii and brachialis muscle thickness (MT) were compared between groups by split-plot analyses of variance. RPE was lower (p < 0.05) in ECC-Low (4.0 ± 0.7) and ECC-High (5.1 ± 1.1) than ECC-CON (6.2 ± 1.1). ECC1-RM, MVIC strength at all angles, and concentric peak power increased (p < 0.01) similarly between groups (e.g., ECC1-RM, ECC-CON: 9.8 ± 4.8%, ECC-Low: 10.3 ± 4.9%, ECC-High: 12.8 ± 7.1%), but increases (p < 0.01) in CON1-RM (ECC-CON: 11.8 ± 7.1%, ECC-High: 9.9 ± 5.3%) and MT (3.9 ± 3.1%, 5.4 ± 4.4%) were evident only after ECC-CON and ECC-High without a difference. These results did not fully support the hypothesis, but ECC-Low was effective for improving 6 of 8 measures similarly to ECC-High and ECC-CON with lower RPE. This suggests the efficacy of eccentric-only resistance exercise training for individuals who are novice in elbow flexor resistance exercise training.

matched text: “elbow flexion”

Introduction Neuromuscular fatigue disrupts rowing technique, yet its multisegmental effects in Traditional fixed-seat rowing remain poorly understood. This study examined the phase-specific impact of fatigue on joint angles, body segment heights, and center of gravity position at the catch and finish phases. Methods Nineteen elite male Traditional rowers (age: 29.4 ± 7.0 years, height: 182.0 ± 6.1 cm, body mass: 78.2 ± 8.0 kg) competing in the ACT, the highest Traditional rowing league division, were recruited for a within-subject pre–post design; two did not complete the post-fatigue assessment and marker availability varied, so paired analyses included ≤17 complete cases per variable. Following a pre-fatigue kinematic assessment, participants performed a standardized incremental test to volitional exhaustion on a fixed-seat ergometer. Three-dimensional kinematic data were captured using an STT Systems 3DMA. Paired-samples t -tests compared pre- and post-fatigue conditions, with Benjamini–Hochberg correction for multiple comparisons and Cohen's d as effect size. Results Body segment heights decreased significantly after fatigue and remained significant after correction. At the catch, head (1,182.0 vs. 1,163.8 mm), shoulder (914.3 vs. 882.9 mm) and hand heights (641.1 vs. 626.9 mm) were reduced (adjusted p ≤ 0.042; d = −0.72 to −1.19); at the finish, head (1,073.7 vs. 1,049.0 mm) and hand heights (989.3 vs. 962.8 mm) were reduced (adjusted p = 0.024; d = −0.78 and −0.79). The vertical center of gravity decreased at both the catch (659.4 vs. 647.9 mm; adjusted p = 0.045; d = −0.64) and finish (565.2 vs. 551.5 mm; adjusted p = 0.045; d = −0.64). Changes in joint angulations (increased shoulder and elbow flexion, decreased knee flexion) showed unadjusted trends but did not survive correction and are reported as exploratory. Conclusion Neuromuscular fatigue induces distinct, phase-specific kinematic adaptations in Traditional rowing, characterized by a systematic reduction in postural height (all three upper-body landmarks at the catch, and head and hand heights at the finish) and exploratory joint-angle adjustments at the catch and finish. These findings support multisegmental three-dimensional kinematic analysis as a sensitive tool for monitoring fatigue-related technique changes in Traditional rowing, with implications for training design and potential relevance for injury prevention.

matched text: “elbow flexion”