Effects of eccentric exercise on the quadriceps architecture

Abstract

To determine the muscle architecture adaptations in the vastus lateralis (VL) and vastus medialis (VM) after an eccentric training programme based on the Reverse Nordic Hamstring Exercise (RNHE) and after a subsequent detraining period. Subjects and methods: The participants (N = 28) underwent a 12-week intervention, consisting of one week of assessment and familiarisation, followed by seven weeks of eccentric training and four weeks of detraining. The VL and VM muscle architecture features were assessed in resting conditions by means of 2D ultrasonography before (week 1) and after (week 8) the training period, as well as after the detraining period (week 12). Results: Significant increases in the VL and VM muscle fascicle length (FL) (t = − 5.06, d = 1.43, P < 0.05 and t = − 11.14, d = 3.09, P < 0.001, respectively), muscle thickness (MT) (t = − 5.0, d = 1.39, P < 0.05 and t = − 6.17, d = 1.71, P < 0.05) and pennation angle (PA) (t = − 6.77, d = 1.88, P < 0.05 and t = − 4.48, d = 1.25, P < 0.05) were observed after the training period. Conclusion: The FL, MT and PA showed a significant decrease after the detraining period. The results provide evidence that an eccentric training programme based on the RNHE may lead to changes in the VL and VM muscle architecture features, which are reversible after a four-week detraining period.