RT Journal Article SR Electronic T1 Impact of the Nordic hamstring and hip extension exercises on hamstring architecture and morphology: implications for injury prevention JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 469 OP 477 DO 10.1136/bjsports-2016-096130 VO 51 IS 5 A1 Matthew N Bourne A1 Steven J Duhig A1 Ryan G Timmins A1 Morgan D Williams A1 David A Opar A1 Aiman Al Najjar A1 Graham K Kerr A1 Anthony J Shield YR 2017 UL http://bjsm.bmj.com/content/51/5/469.abstract AB Background The architectural and morphological adaptations of the hamstrings in response to training with different exercises have not been explored.Purpose To evaluate changes in biceps femoris long head (BFLH) fascicle length and hamstring muscle size following 10-weeks of Nordic hamstring exercise (NHE) or hip extension (HE) training.Methods 30 recreationally active male athletes (age, 22.0±3.6 years; height, 180.4±7 cm; weight, 80.8±11.1 kg) were allocated to 1 of 3 groups: (1) HE training (n=10), NHE training (n=10), or no training (control, CON) (n=10). BFLH fascicle length was assessed before, during (Week 5) and after the intervention with a two-dimensional ultrasound. Hamstring muscle size was determined before and after training via MRI.Results Compared with baseline, BFLH fascicles were lengthened in the NHE and HE groups at mid-training (d=1.12–1.39, p<0.001) and post-training (d=1.77–2.17, p<0.001) and these changes did not differ significantly between exercises (d=0.49–0.80, p=0.279–0.976). BFLH volume increased more for the HE than the NHE (d=1.03, p=0.037) and CON (d=2.24, p<0.001) groups. Compared with the CON group, both exercises induced significant increases in semitendinosus volume (d=2.16–2.50, ≤0.002) and these increases were not significantly different (d=0.69, p=0.239).Conclusion NHE and HE training both stimulate significant increases in BFLH fascicle length; however, HE training may be more effective for promoting hypertrophy in the BFLH.