The effects of eccentric training on hamstring muscle architecture

Abstract

The architectural features of the hamstring muscle group are important to prevent injury or to reduce the risk of re-injury. Besides, eccentric training is often used in the rehabilitation of hamstring injuries. The aim of this systematic review was to examine the changes created by eccentric training on hamstring muscle architecture and to determine the minimal values of training duration and intensity for requiring functional changes. The research was conducted on the PubMed, Scopus, Web of Science, COCHRANE, CINAHL, and Pedro databases. Full-text studies examining the effect of eccentric training on at least one parameter of the hamstring muscle architecture were included in the review. Studies on cadavers and animals and studies involving different types of training combined with eccentric training were excluded. Twelve of the 7954 studies met the set criteria. According to the results, eccentric training undoubtedly increases fiber length. However, the pennation angle tends to decrease. On the other hand, muscle thickness and cross-sectional area tends to increase depending on the eccentric training. Although the frequency, number of sets and number of repetitions in sets were similar in the examined studies, muscle architecture changes were different. We think that eccentric training duration and the number of repetitions in total or per training session seem to have an impact on muscle architecture. In order to determine the minimal eccentric training program that can create these changes, quality research is needed to examine the duration, intensity and methods of eccentric training.

The chronic effects of eccentric exercise interventions in different populations: an umbrella review

“…On the other hand, Roig et al 23 thought that the greatest increase in the cross-sectional area can be obtained especially at higher levels of intensity of the eccentric resistance training. Eccentric training also greatly increased fascicle length compared to baseline results, 32,33 while greater increase of fascicle length was observed even when comparing the eccentric training results with a group that was executing concentric training. 32 Emirzeoğlu et al 33 added that the increase inside of eccentric group was found independent of duration, frequency of intervention, and the number of repetitions.…”

“…Eccentric training also greatly increased fascicle length compared to baseline results, 32,33 while greater increase of fascicle length was observed even when comparing the eccentric training results with a group that was executing concentric training. 32 Emirzeoğlu et al 33 added that the increase inside of eccentric group was found independent of duration, frequency of intervention, and the number of repetitions. It was found that hamstring fascicle length increased greatly when Nordic hamstring exercise was implemented in the warm-up (before the training session), while muscle thickness and pennation angle increased greatly after implementing Nordic hamstring exercise after the training session.…”

“…The results were presented as the rating of overall confidence in the range of critically low overall confidence and high overall confidence (See Supplementary Materials: Table 1.). Sixteen studies had a critically low rating of overall confidence, 22,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] thirteen had a low rating of overall confidence, 6,17,23,[42][43][44][45][46][47][48][49][50][51] no studies had a moderate rating of overall confidence, and 6 had a high rating of overall confidence. 21,[52][53][54][55][56] Eleven out of 35 reviews were not limited to studies that included a control group to compare outcomes obtained between the experimental group (which implemented eccentric exercise) and the control group(/-s) (which implemented other types of therapies, other exercise interventions, or no intervention at all).…”

“…32 Douglas et al 32 pointed out that particularly heavier eccentric training caused greater muscle hypertrophy and increased cross-sectional area, while Roig et al 23 emphasized that eccentric resistance training performed outstanding improvements in eccentric strength, muscle girth, and cross-sectional area compared to concentric training. Eccentric exercise in general greatly increased fascicle length too, 32,33,37 but Emirzeoğlu et al 33 added that the increase was found independent of duration and frequency of intervention, and a number of repetitions. The other authors 53 who were focused particularly on the effects of Nordic hamstring exercise agreed with Douglas et al 32 and Emirzeoğlu et al, 33 but added that they found out that in the case of implementing Nordic hamstring exercise in the training session, it provided great results (increased hamstring fascicle length) only when the exercise was performed before the training session (in warm-up).…”

“…32,36 Executing eccentric exercise was found to increase muscle cross-sectional, and distal muscle size, especially the fast-twitch muscle fibers to a greater range compared to concentric exercise. 32,33,38,41 Nevertheless, authors 23,32 pointed more solutions, how to achieve the greatest increase in cross-sectional area. Douglas et al 32 thought that the greatest increases of the cross-sectional area can be achieved by rising velocities of exercises and/or by following heavier eccentric training protocol.…”