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Razor hamstring curl and Nordic hamstring exercise architectural adaptations : Impact of exercise selection and intensity
Pollard, Christopher W. Opar, David A. Williams, Morgan D. Bourne, Matthew N. Timmins, Ryan Gregory
Pollard, Christopher W.
Opar, David A.
Williams, Morgan D.
Bourne, Matthew N.
Timmins, Ryan Gregory
Abstract
Objectives: To investigate knee flexor strength and biceps femoris long head (BFlh) architectural adaptations following two different Nordic hamstring exercise (NHE) interventions and one razor hamstring curl (RHC) intervention.
Methods: Thirty recreationally active males performed a total of 128 reps of NHE<sub>bodyweight</sub> (n = 10), NHE<sub>weighted</sub> (n = 10), or RHC<sub>weighted</sub> training (n = 10) across 6 weeks. Following the intervention, participants avoided any eccentric training for 4 weeks (detraining period). Strength results during the NHE and RHC were recorded pre‐ and post‐intervention, as well as following detraining. Architectural characteristics of the BFlh were assessed weekly throughout the intervention and detraining periods.
Results: For the NHE<sub>weighted</sub> group, NHE strength increased (+81N, P = 0.044, d = 0.90) and BFlh fascicles lengthened (+1.57 cm, P < 0.001, d = 1.41) after 6 weeks of training. After 1 week of detraining, BFlh fascicle lengths shortened, with the largest reductions seen in the NHE<sub>weighted</sub> group (−0.96 cm, P = 0.021, d = −0.90). Comparatively, BFlh fascicle length and NHE strength responses were moderate in the NHE<sub>bodyweight</sub> group and negligible in the RHC<sub>weighted</sub> group. The greatest RHC strength changes (+82N, P = 0.038, d = 1.15) were seen in the RHC<sub>weighted</sub> group.
Conclusions: NHE<sub>weighted</sub> interventions induce large BFlh fascicle lengthening responses and these adaptations decay after just 1 week of detraining. NHE<sub>bodyweight</sub> training has a moderate impact on BFlh architecture while the RHC<sub>weighted</sub> group has the least. Weighted NHE and RHC training promoted exercise‐specific increases in strength. These findings suggest that exercise selection and intensity should be considered when prescribing exercises aiming to increase eccentric strength and BFlh fascicle length.
Keywords
eccentric training, fascicle length, muscle architecture, ultrasound
Date
2019
Type
Journal article
Journal
Scandinavian Journal of Medicine & Science in Sports
Book
Volume
29
Issue
5
Page Range
706-715
Article Number
ACU Department
School of Behavioural and Health Sciences
Faculty of Health Sciences
Faculty of Health Sciences
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Event URL
Open Access Status
Published as green open access
License
File Access
Open
Open
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Open
Open
Controlled
Open
Open
Open
Open
Open
Controlled
Open