REF-1796 · Franke et al., 2026 · International Journal of Sports Medicine · Paper · PubMed

One set of six Nordic hamstring repetitions a week in season did not keep the eccentric hamstring strength 34 athletes had gained in a 5-week preseason Nordic block (+9.5%): by in-season week 5 both the microdose and the no-Nordic group were back near baseline, with no significant difference between them

Eccentric strength, not injuries, in one randomised trial

Main caveat: One dose tested (1 × 6 a week); the dose that retains strength is not identified.
moderate evidenceMeasured on trained athletesRead from the abstract only

Franke and colleagues tested whether a very small weekly dose of the Nordic hamstring exercise during the competitive season keeps the eccentric strength built in preseason.

Thirty-four athletes first completed a 5-week preseason programme that included Nordics at a typical volume of up to 60 repetitions a week, and were then randomised to stop Nordics entirely or to do one set of six repetitions a week through the season. Eccentric hamstring strength was measured at baseline, at the end of preseason and after 5 and 10 in-season weeks.

Preseason raised strength by a mean 9.5% (95% CI 5.3 to 14.3%). By week 5 of the season strength had returned to baseline levels in both groups and stayed there to week 10, and the groups did not differ significantly. The authors conclude that this microdose was not enough to retain the preseason gain.

Participants

34 athletes; sport, sex, age and competition level are not in the abstract.
Arm sizes are not given; about 17 per arm by our arithmetic.

Protocol

Preseason (both groups): 5 weeks including a typical-volume Nordic protocol, up to 60 repetitions a week.
In season, 10 weeks: control = no Nordics; microdose = 1 set of 6 Nordic repetitions a week.
Eccentric hamstring strength (in newtons) at baseline, end of preseason, in-season week 5 and week 10; the test device is not named in the abstract.
Not in the abstract: the sport's in-season training and match load, adherence to the microdose, dropouts, and whether testers were blinded.

Key Results

Time pointMicrodose (N, mean ± SD)Control (N, mean ± SD)
Baseline317 ± 82292 ± 82
End of preseason346 ± 82321 ± 82
In-season week 5324 ± 83289 ± 83
In-season week 10330 ± 83290 ± 84
Preseason gain, both groups together: +9.5% (95% CI 5.3 to 14.3%).
After 5 in-season weeks strength was back at baseline levels in both groups and stable to week 10; no significant between-group differences.

Practical Application

Six Nordic reps once a week did not hold the eccentric strength gained in preseason: within 5 weeks of the season it was back near baseline, as in athletes who dropped Nordics altogether. Eccentric strength, not injury, in one trial of 34 athletes.
Where it meets the base: it limits, but does not contradict, [SYNTH-59]'s "a low volume kept up". That line rests on REF-887, where low- and high-volume Nordic programmes of 6 weeks or more built similar eccentric strength (its volume bands are not given in repetitions).This trial asked a different question: whether 1 set of 6 Nordics a week keeps a gain built in 5 preseason weeks on up to 60 a week; over 10 in-season weeks it did not.A low building volume is still supported and the Nordic stays in the week; what this adds is that one weekly set of 6 was too little to hold eccentric strength in these athletes, and the dose that holds it is unknown.
Inference, not tested here: a larger in-season dose (more sets, or twice a week) may hold more; this trial tested only one dose, so the amount that does retain strength is unknown. Nor does it contradict SYNTH-106: that guide's "one strength session a week held strength" rests on full sessions with the usual exercises and loads over 12 weeks in small trials (REF-1628, REF-1136); one set of one exercise is a far smaller dose, tested on a different strength measure.
Do not read this as injury evidence. Whether losing the strength gain changes hamstring injury risk was not measured; injury protection from Nordic programmes rests on REF-766.
This is not injury treatment advice; a hamstring strain is assessed and rehabilitated with a physiotherapist or sports physician.

Limitations

One dose tested (1 × 6 a week); the dose that retains strength is not identified.
The groups differed by about 25 N at baseline (our arithmetic) and stayed apart, and the SDs are large (about 82 N); the study may be too small to show a modest difference. In season the microdose group stayed 7-13 N above its own baseline and the control group 2-3 N below it (our arithmetic from the group means; not tested in the abstract), so a small retained effect is not excluded.
Sport, sex, competition level, in-season training load, adherence and the strength device are not in the abstract.
Eccentric strength only; no injury, sprint or architecture outcome.
Written from the abstract and the PubMed record; full text not read.
How this entry was checked and changed
Why this level

a parallel RCT with about 17 per arm (34 in two arms), read from the abstract: risk of bias not read (abstract only)