Ryan G Timmins1, Joshua D Ruddy, Joel Presland, Nirav Maniar, Anthony J Shield, Morgan D Williams, David A Opar. 1. 1School of Exercise Science, Australian Catholic University, Melbourne, AUSTRALIA; 2School of Exercise and Nutrition Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, AUSTRALIA; and 3School of Health, Sport and Professional Practice, University of South Wales, Pontypridd, Wales, UNITED KINGDOM.
Abstract
PURPOSE: To determine the architectural adaptations of the biceps femoris long head (BFlh) after concentric or eccentric strength training interventions and the time course of adaptation during training and detraining. METHODS: Participants in this intervention (concentric training group [n = 14], eccentric training group [n = 14], male subjects) completed a 4-wk control period, followed by 6 wk of either concentric- or eccentric-only knee flexor training on an isokinetic dynamometer and finished with 28 d of detraining. Architectural characteristics of BFlh were assessed at rest and during graded isometric contractions using two-dimensional ultrasonography at 28 d prebaseline; baseline; and days 14, 21, and 42 of the intervention and then again after 28 d of detraining. RESULTS:BFlh fascicle length was significantly longer in the eccentric training group (P < 0.05; d range, 2.65-2.98) and shorter in the concentric training group (P < 0.05; d range, -1.62 to -0.96) after 42 d of training compared with baseline at all isometric contraction intensities. After the 28-d detraining period, BFlh fascicle length was significantly reduced in the eccentric training group at all contraction intensities compared with the end of the intervention (P < 0.05; d range, -1.73 to -1.55). There was no significant change in fascicle length of the concentric training group after the detraining period. CONCLUSIONS: These results provide evidence that short-term resistance training can lead to architectural alterations in the BFlh. In addition, the eccentric training-induced lengthening of BFlh fascicle length was reversed and returned to baseline values after 28 d of detraining. The contraction mode specific adaptations in this study may have implications for injury prevention and rehabilitation.
RCT Entities:
PURPOSE: To determine the architectural adaptations of the biceps femoris long head (BFlh) after concentric or eccentric strength training interventions and the time course of adaptation during training and detraining. METHODS:Participants in this intervention (concentric training group [n = 14], eccentric training group [n = 14], male subjects) completed a 4-wk control period, followed by 6 wk of either concentric- or eccentric-only knee flexor training on an isokinetic dynamometer and finished with 28 d of detraining. Architectural characteristics of BFlh were assessed at rest and during graded isometric contractions using two-dimensional ultrasonography at 28 d prebaseline; baseline; and days 14, 21, and 42 of the intervention and then again after 28 d of detraining. RESULTS: BFlh fascicle length was significantly longer in the eccentric training group (P < 0.05; d range, 2.65-2.98) and shorter in the concentric training group (P < 0.05; d range, -1.62 to -0.96) after 42 d of training compared with baseline at all isometric contraction intensities. After the 28-d detraining period, BFlh fascicle length was significantly reduced in the eccentric training group at all contraction intensities compared with the end of the intervention (P < 0.05; d range, -1.73 to -1.55). There was no significant change in fascicle length of the concentric training group after the detraining period. CONCLUSIONS: These results provide evidence that short-term resistance training can lead to architectural alterations in the BFlh. In addition, the eccentric training-induced lengthening of BFlh fascicle length was reversed and returned to baseline values after 28 d of detraining. The contraction mode specific adaptations in this study may have implications for injury prevention and rehabilitation.
Authors: David A Opar; Ryan G Timmins; Fearghal P Behan; Jack T Hickey; Nicol van Dyk; Kara Price; Nirav Maniar Journal: Sports Med Date: 2021-04-29 Impact factor: 11.136
Authors: Maria João Valamatos; Francisco Tavares; Rute M Santos; António P Veloso; Pedro Mil-Homens Journal: Eur J Appl Physiol Date: 2018-07-07 Impact factor: 3.078
Authors: Matthew N Bourne; Ryan G Timmins; David A Opar; Tania Pizzari; Joshua D Ruddy; Casey Sims; Morgan D Williams; Anthony J Shield Journal: Sports Med Date: 2018-02 Impact factor: 11.136