Affiliations: [a] Faculty of Science Education and Sport, University of Vigo, Pontevedra, Spain | [b] Education, Physical Activity and Health Research Group (Gies10-DE3), Galicia Sur Health Research Institute, University of Vigo, Vigo, Spain | [c] Faculty of Sport, University of Porto, Porto, Portugal
Correspondence:
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Corresponding author: Diego Alonso-Fernandez, Faculty of Science Education and Sport, University of Vigo, Campus A Xunqueira s/n. 36005, Pontevedra, Spain. Tel.: +351 34 896 801744; Fax: +351 34 986 801701; E-mail: diego_alonso@uvigo.es.
Abstract: BACKGROUND: Eccentric strength training changes muscle architecture but it is also an important factor for the prevention of injuries and their rehabilitation. OBJECTIVE: To determine the architectural adaptations of the semitendinosus (ST) after an eccentric strength training protocol with Nordic hamstring exercise (NHE), followed by a subsequent detraining period. METHODS: Twenty-three male individuals, aged 25.5 ± 3.3, completed an 8 week intervention, where the architectural characteristics of the ST were evaluated using a two-dimensional ultrasound before (pretest-week-1), after the training period (posttest-week-9) and at the end of the detraining period (retest-week-13). RESULTS: The post-test scores indicated that eccentric strength training resulted in a significant increase in the fascicle length (FL) (t =-12.5, d= 3.53, P< 0.01) and muscle thickness (MT) (t =-9.69, d= 2.85, P< 0.01), whereas the pennation angle (PA) decreased significantly (t = 6.42, d= 1.76, P< 0.01). In retest, both FL (t = 9.7, d= 2.65, P< 0.01) and MT (t = 9.18, d= 2.65, P< 0.01) decreased significantly, whereas PA showed a significant increase (t =-5.39, d= 1.47, P< 0.01). CONCLUSION: The NHE seems to generate adaptations in ST architecture, which, in addition, are also reversible after a detraining period. These results may have practical implications for injury prevention and rehabilitation programmes.
