The Effect of Nordic Hamstring Exercise Intervention Volume on Eccentric Strength and Muscle Architecture Adaptations: A Systematic Review and Meta-analyses
The review asked whether a lower Nordic hamstring exercise (NHE) volume produces the same adaptations as the high doses in the usual prevention programmes, whose volume may explain poor compliance in professional soccer. Thirteen studies of at least 4 weeks that measured biceps femoris architecture were analysed.
After interventions of 6 weeks or more, low- and high-volume NHE training both produced very large gains in eccentric strength and fascicle length and a reduction in pennation angle. The authors conclude that reducing NHE volume does not blunt these adaptations and that lower volumes may be more appropriate for athletes to raise compliance.
Participants
13 studies included (from 293 identified). The number of participants and their sports are not given in the abstract.
Protocol
Search of SPORTDiscus, Ovid and PubMed; 293 studies identified.
Inclusion: (1) at least 4 weeks of NHE training; (2) pre- and post-intervention mean ± SD reported; (3) biceps femoris muscle architecture measured → 13 studies.
Study quality by the TESTEX criteria; risk of bias by fail-safe N (Rosenthal method); consistency by I2.
Hedges' g effect sizes within studies; between-study differences by a random-effects model.
Key Results
Study quality: TESTEX scores ranged from 3 to 11 out of 15.
Bias: "low risk of bias" in the included randomised controlled trials; fail-safe N of 250 (strength) and 663 (architecture), p < 0.001.
Heterogeneity: I2 = 58.58% for strength (the abstract printed 62.49%; corrected in the published erratum, doi 10.1007/s40279-019-01208-4) and 88.03% for muscle architecture (moderate to high).
Eccentric strength after interventions of ≥ 6 weeks: very large positive effects for both high volume (g = 2.12) and low volume (g = 2.28).
Fascicle length: g ≥ 2.58; pennation angle: large-to-very-large reduction, g ≥ 1.31.
Between-study differences: magnitude 0.439 (p = 0.001) for strength (the abstract printed 0.374, p = 0.009; corrected in the erratum) and 0.793 (p < 0.001) for architecture.
Practical Application
Across 13 Nordic hamstring training studies, interventions of 6 weeks or more gave the same very large gain in eccentric hamstring strength at low volume as at high volume (g = 2.28 vs g = 2.12), with fascicle length also rising (g ≥ 2.58). To "how many Nordics do I actually need?": fewer than the classic high-dose programmes, on this evidence; a lower volume done consistently is the authors' recommendation.
The abstract does not define "low" and "high" volume in repetitions or sets per week. Do not quote a weekly rep count from this entry.
Give it time: the effects above are for interventions of at least 6 weeks.
The injury link is the authors' reasoning, not this paper's outcome: the adaptations "may reduce" hamstring strain risk. For the injury evidence itself, REF-766 found that programmes including the NHE roughly halve hamstring injuries.
Not from this paper; the base's own practice: where the Nordic sits in a sprinter's week is in SYNTH-59.
Limitations
Moderate-to-high heterogeneity (I2 58.58% after correction and 88.03%) and study quality from 3 to 11 of 15 on TESTEX.
Outcomes are eccentric strength and muscle architecture, not injury rates.
Volume categories, participant numbers and sports are not given in the abstract.
An erratum exists (Sports Med 2020;50(1):101-102); its content was not checked.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level
SR/MA with moderate-to-high heterogeneity (I2 58.58% strength (corrected from 62.49%), 88.03% architecture) and variable study quality
Content correction 2026-09-29
2026-09-29: the published correction (Sports Med 2020;50:101-102, doi 10.1007/s40279-019-01208-4, open access) changes the strength heterogeneity I2 62.49% -> 58.58%, the between-study variance 0.374 (p = 0.009) -> 0.439 (p = 0.001) and one fail-safe N (250 -> 178); the main finding (low vs high NHE volume, g = 2.28 vs 2.12) is unchanged. Numbers updated.
Full text (checked 2026-10-12)
Average weekly volume across the included interventions ranged from 21 repetitions a week to 73 repetitions a week, and most studies built up to highest weekly volumes of 90–100 repetitions, with sets reaching between 8 and 12 repetitions towards the end (full text).
In the direct volume comparison (Presland et al., recreationally active males, 6 weeks), the high-volume group did 392 total reps (73 average weekly) and the low-volume group 80 total reps (21 average weekly), the low-volume group dropping to "2 × 4 × 1" in weeks 3–6 after the same baseline weeks 1–2 (full text, Table 2).
Presland et al. found no statistical difference (P = 0.982) in fascicle-length gains between high and low volume, while the low-volume group showed significantly greater (P < 0.001) decreases in pennation angle (full text).
Interventions of only 4 weeks found trivial to small pre-post differences; large-to-very large effect sizes appeared only in the single 6-week study, and moderate to very large increases in the 8–10 week studies (full text).
Study samples ranged from n = 9 to n = 35 and were mostly male (recreationally active males, soccer players, sprinters), with one group of amateur female rugby union players (n = 24), adolescent team-sport athletes and healthy boys aged 10–12 (full text, Table 2).
The classic Mjølsnes 10-week protocol totals 700 NHE; its compliance was 96%, a replication reached 60%, and the same intervention given to UEFA Champions League clubs had compliance as low as 16.7% (full text).
Three studies rated soreness on a visual analogue scale, with scores no higher than six out of ten, and no intervention produced a meaningful change in muscle size (g ≤ 0.47) (full text).