Guides · NordBord · 7 min read
NordBord results explained: max force, N/kg, imbalance % and what counts as a red flag
How to read NordBord results — peak eccentric force, force per kilogram and between-limb imbalance — and the thresholds practitioners actually use.
By Vikas Kashyap · Updated 13 October 2026
The NordBord is the simplest VALD device to run and one of the easiest to misread, because the report boils down to three numbers and it is tempting to look at only one of them. This guide covers the Nordic eccentric test (the standard protocol), what each number means, and how to combine them into a decision.
The three numbers
| Number | What it is | Why it matters |
|---|---|---|
| Peak eccentric force, left and right (N) | The highest force each hook records during the eccentric lowering. Reported per limb. | The absolute strength number. Low absolute eccentric hamstring strength has been associated with higher hamstring injury risk in elite cohorts, independent of asymmetry. |
| Relative force (N/kg) | Peak force divided by body mass. | The number to compare across athletes of different sizes, and the one most normative datasets are expressed in. |
| Imbalance (%) | The between-limb difference expressed relative to the stronger limb. | The injury-risk and rehab-progression number. Also the most over-read one — see below. |
Thresholds practitioners use
Thresholds in this area come from prospective studies in elite Australian rules football and elite soccer, and from return-to-play consensus work. They are guides, not rules, and every squad should refine them from its own data. The ones you will hear most often:
- Absolute force: the most-cited figure from the AFL prospective work is that athletes with peak eccentric force below roughly 337 N had substantially elevated hamstring injury risk. Many elite programmes use a target in the 350–400 N range for senior male athletes and scale it for women and youth.
- Imbalance: 10% is the common flag; 15% or more is the common action threshold. In return-to-play, the injured limb is usually required to reach at least 90% of the uninjured limb (a 10% imbalance) before full training.
- Rate of change: a drop of more than about 10% in an athlete's own peak force between weekly tests, in the absence of a planned heavy eccentric block, is worth a conversation regardless of where it sits against the threshold.
Reading the trend
NordBord testing is typically weekly in-season, which gives you a dense time series per athlete. Three patterns are worth learning to spot:
- A slow decline in both limbs over 3–4 weeks with training load unchanged — accumulated fatigue, often before the athlete reports it.
- One limb falling while the other holds — the pattern that precedes a strain in some cohorts, and the one to catch early.
- A sudden recovery of imbalance in rehab without a recovery of absolute force — the athlete has got symmetric by the uninjured limb getting weaker, not the injured limb getting stronger. It looks like progress on the imbalance chart and is not.
Protocol notes that change the numbers
- Warm-up and familiarisation affect peak force meaningfully. Test after a standard warm-up, every time.
- Cueing matters: 'lower as slowly as possible' produces different force than 'resist as hard as you can'. Pick one cue and keep it.
- Record the best of three trials, not the mean, unless your monitoring has always used the mean. Do not mix.
- Hook height and knee position on the board change the lever. Set it once per athlete and note it.
Putting it next to the rest of the athlete
A hamstring finding rarely lives alone. A fall in NordBord force in the same fortnight as a single-leg CMJ asymmetry on ForceDecks, or a hip strength change on ForceFrame, is a clearer picture than any of the three on its own. The practical problem is that the three live in three exports, and the join is done by hand — which is why so many programmes never make it.
How Kinexis handles this
Kinexis puts NordBord peak force, N/kg and imbalance on the same athlete profile as their ForceDecks and ForceFrame testing, tracks each against the athlete's own baseline and your thresholds, and writes the flag in words — 'left eccentric force −11% over three weeks, imbalance now 14%, single-leg CMJ asymmetry also left-sided' — for every athlete in the squad after each testing session.
- Hamstring strength relative to body weight, left and right, against your target.
- The left–right gap beside it with the weaker leg named: force first, imbalance second.
- Quads, adductors and abductors on the same wheel, so the hamstring number is never read alone.
- A squad view: who is on target, who is close, who is under, and which leg is weaker across the group.