Track the last four weeks of total running minutes, multiply the most recent week by 1.2, and stop training the moment that figure overtakes the previous three-week rolling average. A squad of 42 Danish Superliga players followed this rule for two seasons; only three suffered lower-limb muscle tears compared with ten in the control group who tolerated a 1.5 spike.

English Premier League data from 2025-26 show the same threshold: athletes who breached 1.25 were 5.6 times more likely to miss matches within the next fourteen days. GPS outputs from 237 fixtures reveal that soft-tissue casualties averaged 98 high-speed metres per minute in the spike week, while uninjured teammates held 76 m·min⁻¹. The difference is 22 m·min⁻¹-roughly two extra 30 m sprints every quarter hour.

Programmers can automate the flag in less than twenty lines of Python: pull daily distance from Polar, sum seven-day windows, divide by the preceding twenty-one, and push a red alert to the physio’s phone if the value ≥ 1.15. Brighton & Hove Albion built this micro-service in forty-eight hours and saved an estimated £340 000 in wages otherwise paid to sidelined talent.

Calculate 7-Day vs 28-Day Load in Excel Sheets

Insert a new sheet named Calc, list dates down column A starting at A2, then in B2 enter =SUMIFS(Data!C:C,Data!A:A,">="&A2-6,Data!A:A,"<="&A2) to pull the past seven days’ training impulse. Copy this formula down 28 rows. In C2 write =SUMIFS(Data!C:C,Data!A:A,">="&A2-27,Data!A:A,"<="&A2)/4 to average the last four weeks. Drag the fill handle; conditional-format column D with =B2/C2>1.5 to turn cells red when the short-term spike exceeds the safe 1.3-1.5 band.

Keep raw session data on a sheet called Data: date in A, sport-specific stress score (RPE × minutes) in C. Freeze row 1, add a dynamic chart: select A:A and B:C, insert line, set x-axis to Date, primary y-axis for weekly stress, secondary y-axis for rolling four-week mean. Save the workbook as a macro-enabled template; assign Ctrl+Shift+R to a button that refreshes the query, sorts newest first, and exports the last 35 rows to a csv for the squad dashboard.

Spot Red-Zone Athletes with 1.5 Cut-Off Alerts

Spot Red-Zone Athletes with 1.5 Cut-Off Alerts

Flag any athlete whose last-week stress score exceeds the preceding four-week average by ≥1.5×; push the name straight to the medical Slack channel within 5 min of the overnight sync.

  • Last-week stress = sum of (session-RPE × minutes) for days 1-7.
  • Four-week baseline = mean of the four previous seven-day blocks.
  • 1.5× threshold yields 78 % sensitivity and 82 % specificity for a time-loss event within the next 10 days in 312 pro footballers (Ortega 2025).

Automate the math in the SQL view: SELECT player_id, ROUND(last7/mean28,2) AS spike FROM workload WHERE last7/mean28 >= 1.5; Push the resulting list to a red-label Grafana panel that refreshes every 30 s.

  1. Once the spike triggers, the physio has a 24-hour window to cut the next planned micro-cycle by 30 % and swap one high-speed session for a 20-min pool flush.
  2. Keep the athlete below 0.9× baseline for 72 h; retest a counter-movement jump; green-light normal build only if RSImod is within 5 % of individual February mean.
  3. Log every action in the AMS; the audit trail cuts insurance premiums 11 % (AFL data 2021-23).

Goalkeepers and pitchers behave differently: use a 1.4× cut-off if weekly high-speed runs <3 km or competitive throws <50; still keep the same alert colour code so coaches don’t second-guess the dashboard.

Weekly false-positive noise drops from 18 % to 6 % when you add a second rule: red label sticks only if perceived sleep (1-10 scale) also drops ≥2 points from the player’s rolling 28-night median. Filter early, intervene faster, keep more athletes on the field.

Adjust Pitch Counts to Drop Ratio Below 0.8 in 72 h

Adjust Pitch Counts to Drop Ratio Below 0.8 in 72 h

Cut the next bullpen to 18 pitches if yesterday’s game hit 95; this drives the 7-day rolling tally versus the 28-day baseline under 0.8 inside the 72-hour window. Keep post-session RPE ≤4, cap fastballs at 60 % of those 18, and slot the outing 11 hours after high-resolution HRV returns to the athlete’s 8-week mean. Pair the work with 12 min of prone diaphragmatic breathing at 6 br·min⁻¹ to accelerate parasympathetic rebound, then retest countermovement jump height; a drop >6 % triggers an extra rest day before mound work resumes.

StepMetricTarget
1Daily throws≤18
2Fastball %≤60
3RPE≤4
4HRV delta±3 ms
5CMJ loss<6 %

Between sessions, prescribe 3 × 8 eccentric Cuban rolls at 15 % body-mass to reinforce rotator cuff and 2 × 30 s single-leg balance eyes-closed to re-establish proprioception after fatigue. Hydration target: 1 g carbohydrate kg⁻¹ and 15 ml kg⁻¹ fluid within 30 min of shutdown, adding 0.3 g kg⁻¹ whey isolate to shave creatine-kinase rise by 22 % at 24 h follow-up. If the 72-hour marker passes without the quotient dipping under 0.8, scrap live batting practice, shift to 12-pitch mirror mechanics at 50 % intensity, and re-evaluate after another 48-hour cycle.

Swap Sprint Volume Without Spiking Monday Ratio

Cut the planned 8×30 m at 95 % on Saturday, add 6×20 m at 92 % on Wednesday: the 240 m removed from the 7-day tally keeps the rolling 28-day denominator steady at 1 120 m, so the Monday spike stays ≤ 0.9.

Need more speed? Exchange 4 of the Wednesday reps for 3×30 m sled pulls at 70 % body-mass; the horizontal impulse rises 11 % while the weekly tally only inches up 60 m, leaving the 4-week average untouched at 1 180 m and the Monday quotient at 0.88.

Validate HRV Against Ratio for Non-Contact Injury Flags

Flag rMSSD drop ≥12 % within 7-day window when 4-week rolling workload climbs >1.35× baseline; pull the player next session.

Ultrashort HRV (55 s seated, Polar H10) collected 04:00-06:00 beats the 1.35× marker for forecasting hamstring or adductor mishaps (r = 0.62, n = 48 elite U-23 footballers, 2026-24 preseason). Sensitivity 0.83, false-positive rate 0.11, better than any GPS-derived metric alone.

Protocol checklist:

  • Same 5-min supine rest before recording
  • Room 20 °C, <45 dB
  • Caffeine withheld ≥9 h
  • Manual artefact check; <5 % ectopics or discard

Case: Serie A winger, week -2 pre-derby, 4-week exponentially-weighted sum = 1.41, rMSSD 64→51 ms (-20 %). Flagged, kept to 40 % volume next day, no mishap; teammate ignored alert, tore biceps femoris 72 h later.

Threshold recalibration needed for women: same 1.35× cut-off drops sensitivity to 0.68 (NWSL data). Use 1.25× plus rMSSD ≥10 % fall.

Combine with red-zone sprint tally: if HRV red AND >10 efforts >85 % top speed within micro-cycle, probability spikes to 0.91.

Export CSV from Kubios cloud → Python script (provided on GitHub) to merge with Catapult CSV; 8-line code prints daily traffic-light column.

Contested referee call altered match flow, spiking 2nd-half strain 18 %; details: https://likesport.biz/articles/it-was-a-foul-garcia-baffled-gironas-winner-allowed-to-stand-and-more.html

Present Coach Dashboards That Trigger 10 % Load Cuts

Paint a 4-week rolling stress score on the left y-axis, 7-day stress on the right, and color the bar red when the gap exceeds 1.4; auto-send an SMS that slashes next-week targets by 10 % the instant the red bar appears.

Embed a traffic-light tile: green keeps the planned minutes, amber trims 5 %, red drops 10 % and locks the calendar until the athlete confirms a 9-h sleep slot.

One women’s volleyball squad used this widget for nine months: soft-tissue cases fell from 11 to 3, average blocks jumped 8 %, and starters lost only 14 total practices versus 47 the year before.

FAQ:

My coach keeps talking about keeping the acute load within 1.5 times the chronic load. Where do these exact numbers come from and are they set in stone?

The 1.5 figure is borrowed from cricket fast-bowling research (Hulin 2014). Over two seasons the authors counted every ball bowled, rated each session RPE, then plotted next-week injury likelihood. The sweet spot sat near 0.8-1.3, while risk climbed sharply above 1.5. Later papers on AFL, rugby and soccer found similar inflection points, so the number stuck. It is not a law: adolescents, females and masters athletes often tolerate lower ratios, whereas elite endurance runners can stay healthy around 1.8 when ramped gradually. Treat 1.5 as the first yellow flag, not a red light, and adjust for tissue type (tendons hate spikes, bone tolerates them better), sleep debt and past injury.

I’m rehabbing an ACL and just cleared to run; my physio says the graft is back to 60 % of the other knee on the isokinetic test. How should I set the acute : chronic target for the next month so I don’t re-rupture but still progress?

Start the running block with a ratio ≤ 0.8 for the first two weeks. Measure acute load with a weighted formula: minutes × (RPE + 0.5 × limb-symmetry-index). Example: 20 min easy jog at RPE 4 with 60 % symmetry gives 20 × (4 + 0.5 × 0.6) = 86 au. Chronic load is the rolling 28-day average of the same metric. Add one controlled-speed session per week, never raising the ratio more than 0.1 per seven days. Once symmetry hits 80 % and you’ve completed four weeks pain-free, allow the ratio to drift up to 1.0 before any plyometric work. If soreness > 2/10 next morning, repeat the previous week’s load instead of progressing.