Science
These 20 constants are the entire clinical logic of Priveo. There is no model, no scoring engine of our own invention, and nothing learned from your data. When the product flags an athlete, it is because a number crossed one of these lines — and you can read the line.
Your practice can override any of them. A youth academy and a senior squad do not share a sensible sprint-exposure target. Where a threshold is marked overridable, your setting replaces the default and the audit trail records who changed it.
How much work an athlete has done relative to what they are conditioned for, and whether this week is a step or a jump.
{"red":1.5,"blue_lt":0.8,"green_hi":1.3,"week_jump_red":0.15}Acute:chronic workload ratio danger zone begins at 1.5; the 0.8-1.3 band is the sweet spot; a week-on-week acute rise above 15% is itself a spike.
Gabbett 2016 BJSM 50:273; Bowen 2020
{"acute":7,"chronic":21,"uncoupled":true}Uncoupled windows (acute 7d vs the PRIOR 21d) remove the mathematical coupling that inflates the ratio when acute load is inside the chronic window.
Lolli 2019; Fanchini 3:21 alt
{"lambda_a":0.25,"lambda_c":0.069}Exponentially weighted moving averages weight recent load more heavily than a flat rolling average: lambda = 2/(N+1) for N = 7 and N = 28.
Williams 2017 IJSPP
2
Training monotony (7-day mean load / 7-day SD) above 2.0 marks a strained, undifferentiated week; rest days count as zero-load days.
Foster 1998
2584
A 21-day chronic sRPE base at or above 2,584 AU is protective: athletes above the floor tolerate increases in high-speed exposure, while the same exposure below it raises risk. Supersedes the earlier 28-day floor.
Malone (Benfica, 48 weeks)
Daily self-report scored against the athlete's own baseline, in burden direction — higher is worse.
{"red_wi":2,"window":28,"amber_wi":1,"red_item":2.5,"amber_item":1.5,"min_baseline":10}Wellness is scored against each athlete's own 28-day baseline in BURDEN direction (higher z = worse). No flags below 10 baseline days.
IJSPP applied practice; SWC
Near-maximal running is protective in the right dose. Too little is a risk in its own right, which is why a substitute who played fifteen minutes is flagged rather than ignored.
{"green":[4,12],"red_gt":15,"window":21,"min_band":85}Near-maximal sprint exposures over a rolling 21 days: 4-12 protective, more than 15 excessive; a qualifying exposure is >= 85% of max speed.
Colby; Malone; Buchheit
60
A real match counts as high-speed exposure from 60 played minutes. Below that — substitutes, unused squad members, returning players — the exposure must be programmed as a compensation session; matches alone do not vaccinate midfielders, defenders or substitutes.
Buchheit, PSG tracking, 4 seasons
{"W":2,"AT":1.5,"CB":1,"CM":1.5,"FB":2,"GK":1,"CAM":2,"CDM":1}Near-max sprint occurrences are position-dependent: wingers and fullbacks most, central defenders and holding midfielders least. Players fail to reach >90% of max speed in 35% (attackers) to 65% (midfielders) of matches, so expected weekly top-band sessions differ by role.
Buchheit, PSG tracking, 4 seasons
Three lenses on the same test, because any one alone misranks somebody.
{"band":0.12,"buchheit_slope":4,"timmins_floor_n":337,"buchheit_intercept":26.1}Nordic force expected = 4 x body mass + 26.1 N (simple N/kg division misranks heavy athletes); flag beyond -12%; absolute force under 337 N carries ~4.4x hamstring-injury risk.
Buchheit 2016; Timmins 2016
{"pass":0.9,"discharge":0.95}Limb symmetry index gates: 0.90 to progress, 0.95 to discharge. LSI alone never clears an athlete — it is one lens of the battery.
Grindem; Plisky
{"asymmetry_flag":0.1,"baseline_within":0.1}Flag a >10% between-limb adductor difference or >10% below the athlete's own baseline. The adductor:abductor RATIO is displayed but never flagged (2025 meta: SMD -0.02, trivial).
Marković 2020; 2025 BJSM meta
{"vas_max":3,"pain_hours":24}Tendon and lengthening rehab progresses by 24-hour response, never by calendar week: pain must stay at or below 3/10 and must not exceed baseline the morning after.
Rio/PTLE BJSM 2021
The gates between rehab stages, and the psychological readiness score that no amount of force production replaces.
{"time_floor_months":9}Return to sport before 9 months post-ACL-reconstruction multiplies re-injury risk; each month of delay to ~9 months cuts risk by 51%. HARD GATE — not practice-overridable.
Grindem 2016
{"gate":65,"second":76.7,"flat_low":55,"early_spike":80}ACL-RSI psychological readiness: 65 is the clearance gate; 76.7 associates with return to pre-injury level; >= 80 within 3 months post-op is confidence outpacing tissue; a flat mean under 55 in late stage is a confidence gap.
2024 meta; PMC10996360
1.2
Inside the post-clearance window the ACWR amber threshold tightens from 1.3 to 1.2.
Bern consensus 2016; Gabbett 2016
0.1
Inside the post-clearance window the week-jump red threshold tightens from 15% to 10%.
Bern consensus 2016; Gabbett 2016
28
Clearance is not the end of the continuum (Return to Participation -> Sport -> Performance). For 28 days after return the load lane runs at raised sensitivity, because most re-injuries happen after monitoring stops.
Bern consensus 2016
42
A retest battery (injury-site tests vs the EPIC snapshot) falls due six weeks after return to sport.
Bern consensus 2016
The intervention with the best evidence base in the sport, and the adherence it needs to work.
2
FIFA 11+ cuts injuries 30-46% across male youth, collegiate and adult RCTs, but adherence is the determinant: about 40% reduction at two or more sessions per week. Below two, the programme is amber.
FIFA 11+ RCT meta-analyses
The ACWR and Nordic calculators on this site run the same functions against the same rows. Same numbers, same verdicts, no account.