ORIGINAL ARTICLE  SPORT INJURIES AND REHABILITATION 

The Journal of Sports Medicine and Physical Fitness 2019 April;59(4):640-7

DOI: 10.23736/S0022-4707.18.08873-4

Copyright © 2018 EDIZIONI MINERVA MEDICA

lingua: Inglese

Changes in rectus femoris architecture induced by the reverse nordic hamstring exercises

Diego ALONSO-FERNANDEZ ^{1, 2}, Rosana FERNANDEZ-RODRIGUEZ ¹, Rocío ABALO-NÚÑEZ ^{2, 3} ✉

¹ Department of Special Didactics, Faculty of Science Education and Sport, University of Vigo, Vigo, Spain; ² Galicia Sur Health Research Institute (IIS Galicia Sur), Vigo, Spain; ³ Department of Functional Biology and Health Sciences, Faculty of Physiotherapy, University of Vigo, Vigo, Spain

BACKGROUND: Injuries and mechanical stimuli alter the muscle architecture and, therefore, its function. The changes in the architecture of the rectus femoris (RF) induced by an eccentric training protocol with reverse nordic hamstring exercises (RNHE) have never been studied. Therefore, the aim of the present study was to determine the architectural adaptations of the RF after an eccentric training with RNHE, followed by a subsequent detraining period.
METHODS: Twenty-six subjects performed a first week of control, 8 weeks of eccentric training, concluding with a 4-week period of detraining. The architectural characteristics of the RF were evaluated using 2D ultrasound at rest (pretest: week 1), after the training (post-test: week 9), and at the end of the detraining period (retest: week 13).
RESULTS: At the end of the training period, a significant increase in the muscle fascicle length (FL) (t=-8.96, d=2.22, P<0.001), muscle thickness (MT) (t=-8.76, d=2.219, P<0.001), pennation angle (PA) (t=-9.83, d=2.49, P<0.05) and cross-sectional area (CSA) (t=-13.06, d=3.06, P<0.001) was observed. After the detraining period FL, MT, PA and CSA showed a significant decrease.
CONCLUSIONS: The eccentric training with RNHE may cause changes in the architectural conditions of RF, which, in addition, are also reversible after a 4-week detraining period. The adaptations produced by RNHE may have practical implications for injury prevention and rehabilitation programs, which include the changes in muscle architecture variables.

KEY WORDS: Quadriceps muscle - Hamstring muscles - Exercise - Ultrasonography