Training Load Calculator
Session load uses the session-RPE (sRPE) method popularised by Foster: multiply your rating of perceived exertion (0–10) by the session duration in minutes.
Enter Values
How to use this calculator
- For a single session's load, enter the session RPE (0–10 on the Borg CR10 scale) and the duration in minutes — the tool multiplies them to give session load in arbitrary units (AU).
- For the workload ratio, enter this week's total load (acute) and your 4-week rolling weekly average (chronic) in the same AU units; you'll get the ACWR and its risk zone.
- You can fill just the session pair, just the load pair, or both at once — each result appears independently.
How it works
Session load uses the session-RPE (sRPE) method popularised by Foster: multiply your rating of perceived exertion (0–10) by the session duration in minutes. A 45-minute session at RPE 8 is 360 AU. Summing every session's AU over a week gives your weekly (acute) training load in a single, equipment-free number.
The acute:chronic workload ratio (ACWR) divides your most recent week's load (acute) by your longer-term rolling average weekly load (chronic, typically a 4-week average). Ratios around 0.80–1.30 are the commonly cited 'sweet spot', while values above ~1.50 mark a sharp spike that team-sport studies associate with higher injury risk. It is a monitoring signal, not a diagnosis.
Worked example
A 60-minute session at RPE 7, plus a weekly ratio. A footballer rates a 60-minute session at RPE 7, so the session load is 7 × 60 = 420 AU. Over the week their total load is 2,500 AU while their 4-week rolling weekly average (chronic load) is 2,000 AU. The acute:chronic workload ratio is 2,500 ÷ 2,000 = 1.25, which sits inside the 0.80–1.30 'sweet spot' — a controlled, progressive week rather than a dangerous spike.
Common mistakes
- Mixing units between acute and chronic — both must be the same arbitrary units (both sRPE-AU, or both distance, etc.) or the ratio is meaningless.
- Using a session's total load as the chronic figure. Chronic load is a weekly AVERAGE over about 4 weeks, not one session or one day.
- Treating the 0.80–1.30 sweet spot as a hard medical rule. It is a population-level guideline; individual tolerance, fitness and sport vary widely.
Frequently asked questions
What is session RPE (sRPE)?
Session RPE is your overall rating of how hard a whole session felt, on a 0–10 scale, taken about 30 minutes after finishing. Multiplying it by the session's duration in minutes gives a simple training-load score in arbitrary units (AU) that needs no heart-rate monitor or GPS.
What is a safe acute:chronic workload ratio?
Research on team sports often cites 0.80–1.30 as a 'sweet spot', with ratios above roughly 1.50 flagged as a spike linked to higher injury risk. These are guidelines derived from groups of athletes, not personal thresholds — use them alongside how you feel, your training history and coaching advice.
What units is training load measured in?
Arbitrary units (AU). The sRPE method deliberately produces a unitless number so you can compare sessions and weeks against yourself over time; it is not calories, joules or watts.
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