The Dose–Response of the Nordic Hamstring Exercise on Biceps Femoris Architecture and Eccentric Knee Flexor Strength: A Randomized Interventional Trial

Abstract

Purpose: To examine the dose–response of the Nordic hamstring exercise (NHE) on biceps femoris long head (BFlh) architecture and eccentric knee flexor strength. Design: Randomized interventional trial. Methods: Forty recreationally active males completed a 6-week NHE training program consisting of either intermittent low volumes (group 1; n = 10), low volumes (group 2; n = 10), initial high volumes followed by low volumes (group 3; n = 10), or progressively increasing volumes (group 4; n = 10). A 4-week detraining period followed each program. Muscle architecture was assessed weekly during training and after 2 and 4 weeks of detraining. Eccentric knee flexor strength was assessed preintervention and postintervention and after 2 and 4 weeks of detraining. Results: Following 6 weeks of training, BFlh fascicle length (FL) increased in group 3 (mean difference = 0.83 cm, d = 0.45, P = .027, +7%) and group 4 (mean difference = 1.48 cm, d = 0.94, P = .004, +14%). FL returned to baseline following detraining in groups 3 and 4. Strength increased in group 2 (mean difference = 53.6 N, d = 0.55, P = .002, +14%), group 3 (mean difference = 63.4 N, d = 0.72, P = .027, +17%), and group 4 (mean difference = 74.7, d = 0.83, P = .006, +19%) following training. Strength returned to baseline following detraining in groups 2 and 3 but not in group 4. Conclusions: Initial high volumes of the NHE followed by lower volumes, as well as progressively increasing volumes, can elicit increases in BFlh FL and eccentric knee flexor strength. Low volumes of the NHE were insufficient to increase FL, although as few as 48 repetitions in 6 weeks did increase strength.

The dose–response of pain throughout a Nordic hamstring exercise intervention

“…Low volume NHE prescription (Group 2: 2 sets of 4 repetitions once a week for 6 weeks) results in a low pain response (weekly median of 0 for DOMS, with only 10% experiencing non-DOMS pain): this volume has also been shown to be sufficient to increase strength. 8 Whether both strength and architectural changes are required to reduce prospective HSI risk has not yet been elucidated, and NHE volumes demonstrated to be effective in reducing HSI risk have involved high volume programmes. 2 Whether these lower volume protocols may also reduce HSI risk prospectively requires further investigation.…”

“…Higher DOMS and non‐DOMS related musculoskeletal pain is experienced by larger volume NHE prescriptions. Greater NHE volumes increases both strength and architecture adaptation 8 but appear to also increase the risk of DOMS and non‐DOMS pain. 33% of the cohort experienced non‐DOMS related pain, with 85% of these found in the higher volume groups.…”

“…A reduced exercise dosage of NHE (8 repetitions per week from week 3), 5 compared to protocols employed in prevention RCTs (progressing to 90 repetitions per week), 2 is effective for altering biceps femoris long head (BFlh) muscle architecture and eccentric strength, 5 both previously linked to HSI risk, 6 although not consistently 7 . Recently, an even lower volume of NHE was found to be effective for increasing strength (8 weekly repetitions from week 1), while a higher dose was found to be effective for architectural changes 8 . However, the pain response (DOMS and non‐DOMS) to different levels of NHE dosage has not been investigated; this may be useful for guiding exercise prescription and providing insight on adherence.…”

“…for architectural changes. 8 However, the pain response (DOMS and non-DOMS) to different levels of NHE dosage has not been investigated; this may be useful for guiding exercise prescription and providing insight on adherence. Therefore, this study aimed to determine if there is a dose-response relationship between NHE exposure with DOMS and non-DOMS pain.…”

Differences in Peak Knee Flexor Force between Eccentric-Only and Combined Eccentric-Concentric Nordic Hamstring Exercise

“…In fact, it is so common to perform the concentric part of strength exercises that the activities themselves have names that imply the involvement of concentric movement: weight lifting , power lifting . The exception to this rule would be NHE research in which, as mentioned earlier, the typical NHE variation is for the athletes to perform the exercise eccentrically [ 8 , 12 , 20 , 22 , 29 , 30 , 31 ]. However, this differs from the usual practice in strength training and testing, where key exercises like the bench press and barbell squat generally are performed eccentrically-concentrically.…”