calculate-training-load

Calculate Training Load

Quantify the physical stress of training sessions using validated methods to guide load management and reduce injury risk.

Why This Is Best Practice

Adopted by: English Premier League, AFL, NRL, NBA, USA Cycling, elite rugby unions; standard in high-performance sport departments worldwide Impact: Gabbett (2020) showed maintaining acute:chronic workload ratio (ACWR) between 0.8-1.3 reduces injury risk by 20-40% vs. unmanaged spikes; Foster et al. (2001) validated session-RPE as ≥85% correlated with HR-based methods Why best: Without objective load quantification, training spikes go undetected; ACWR bridges the gap between what was planned and what the body actually experienced

Sources: Foster et al. Medicine & Science in Sports & Exercise (2001); Borresen & Lambert Sports Medicine (2009); Gabbett BJSM (2020)

Steps

1. Choose a load metric — Select session-RPE (simplest, validated for most sports), GPS-based PlayerLoad/distance, HR-based TRIMP, or sport-specific volume metrics (km for running, tonnes for weightlifting).

2. Calculate session load (session-RPE method) — Collect RPE on CR-10 or modified Borg scale 30 minutes after each session. Session Load = RPE × Duration (minutes). Example: RPE 6 × 60 min = 360 arbitrary units (AU).

3. Sum weekly acute load — Add all session loads within the past 7 days to get Acute Load (AL).

4. Calculate chronic load — Average the weekly loads over the past 28 days (4-week rolling average) to get Chronic Load (CL). CL = (Week−1 + Week−2 + Week−3 + Week−4) ÷ 4.

5. Compute ACWR — Divide Acute Load by Chronic Load: ACWR = AL ÷ CL. Target range: 0.8-1.3 (safe zone); >1.5 = elevated injury risk.

6. Track monotony and strain — Monotony = Weekly average load ÷ SD of daily loads (high monotony >2.0 signals lack of variation). Strain = Weekly load × Monotony (high strain indicates overtraining risk).

7. Flag spikes — Any week where ACWR exceeds 1.5 or weekly load increases >10% from previous week requires review and potential load reduction.

8. Adjust upcoming training — Use current ACWR and accumulated load to modulate next week's planned sessions; reduce load if ACWR is high, allow slight increase if ACWR is low (0.8-1.0).

9. Log and visualize — Plot load over time in a spreadsheet or sport science software (e.g., Smartabase, Excel) to identify trends; single session data is less useful than trends.

10. Communicate with coaching staff — Share weekly load summaries with coaches; integrate load data into periodization planning decisions.

Rules

• Use the same metric consistently; switching between session-RPE and GPS mid-season invalidates trend comparisons
• Collect RPE at the same post-session interval (30 min is standard) to reduce variability
• ACWR above 1.5 is a caution flag, not a prohibition — context (athlete readiness, competition proximity) determines action
• Never manage load in isolation from wellness data (sleep, HRV, subjective fatigue ratings)

Common Mistakes

• Using only acute load — looking at this week's sessions without chronic context misses the critical ratio; a hard week after light training is more dangerous than the same week in a well-trained athlete.
• Ignoring non-training stressors — travel, competitions, academic stress, and life stress all add to total load but are not captured by session metrics.
• Treating ACWR as a hard rule — rigidly restricting training because ACWR is 1.4 ignores individual differences; use it as one of several inputs.
• Inconsistent RPE collection — if athletes don't understand the scale or report dishonestly, session load calculations are worthless.

When NOT to Use

• Single session planning where cumulative load is not relevant
• Early rehabilitation where pain-guided protocols override load targets
• Sports with highly irregular session structures where consistent RPE collection is impractical