Recovery: Session RPE and Training Load
Foster's sRPE model (2001): session load = RPE (6-20 Borg) × duration in minutes; weekly monotony = mean load / SD; strain = total load × monotony. Monotony >2.0 signals overreaching risk.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Session load formula | RPE × duration | arbitrary units (AU) | Borg CR10 scale (0-10) × session duration in minutes; 7/10 × 60 min = 420 AU |
| Monotony overreaching threshold | >2.0 | unitless ratio | Monotony = weekly mean load / weekly SD; values >2.0 indicate dangerously low variation (Foster et al., 2001) |
| Typical weekly load range | 1000-2500 | AU/week | Moderate training load range for recreational-to-competitive athletes; highly sport and individual dependent |
| Acute:chronic workload ratio safety | 0.8-1.3 | ratio | Acute (7-day) / chronic (28-day) load ratio; values >1.5 associated with elevated injury risk (Gabbett 2016) |
| ACWR injury risk threshold | >1.5 | ratio | Above 1.5, injury incidence increases significantly in team sport athletes; the 'danger zone' |
| RPE scale used | Borg CR10 | 0-10 scale | Modified Borg scale 0-10 is standard for sRPE; full Borg 6-20 scale is also used (multiply results by ~1.5) |
Foster’s session RPE model provides a simple, validated method to quantify training load without technology. Session RPE (sRPE) multiplied by session duration produces an arbitrary unit load score; weekly aggregates reveal patterns that predict overreaching and injury risk.
Alexiou & Coutts (2008 — PMID 18685606) confirmed that sRPE correlates highly with heart rate-based load metrics (r=0.86-0.88 with TRIMP) across team sports, validating its use as a practical daily monitoring tool.
Foster’s sRPE Model Components
| Metric | Formula | Normal Range | Overreaching Threshold | Collection Method |
|---|---|---|---|---|
| Session load | RPE (CR10) × duration (min) | 200-800 AU per session | >1200 AU single session (context dependent) | 30 min post-session self-report |
| Daily load | Sum of all session loads | 200-1000 AU/day | >1200 AU/day sustained | End-of-day total |
| Weekly load | Sum of 7 daily loads | 1000-2500 AU/week | >3000 AU/week (varies by athlete) | Weekly sum |
| Monotony | Weekly mean / weekly SD | <1.5 | >2.0 (Foster et al., 2001) | Calculated from daily loads |
| Strain | Weekly load × monotony | <4000 AU | >6000 AU (elevated risk) | Weekly calculation |
| ACWR (acute:chronic) | 7-day load / 28-day load | 0.8-1.3 | >1.5 (Gabbett, 2016) | Rolling weekly update |
Training Load Zones
| Zone | Weekly Load (AU) | Monotony | Risk Level | Recommended Action |
|---|---|---|---|---|
| Low | <800 | Any | Detraining risk if sustained | Increase load gradually |
| Moderate | 800-2000 | <1.5 | Optimal adaptation range | Maintain; vary intensity |
| High | 2000-3000 | <1.5 | Productive overload | Monitor HRV; ensure recovery |
| High monotonous | 2000-3000 | >2.0 | Overreaching risk | Restructure with variation |
| Excessive | >3000 | Any | Overreaching likely | Mandatory reduction |
| Excessive monotonous | >3000 | >2.0 | Overtraining risk | Immediate deload |
Calculation Example
A 5-day training week with sessions of RPE 6 × 60 min (360 AU), RPE 8 × 45 min (360 AU), RPE 5 × 30 min (150 AU), RPE 7 × 70 min (490 AU), and RPE 9 × 60 min (540 AU): weekly total = 1900 AU, mean = 380, SD = 145, monotony = 2.62 — above threshold despite moderate absolute load (Foster et al., 2001 — PMID 11584843).
How to use this data: Log RPE and duration within 30 minutes of each session. Calculate weekly monotony every Sunday. If monotony exceeds 2.0, restructure the following week to include at least 2 easy days (load <250 AU) between hard sessions. The goal is variation, not load reduction alone.
Related Pages
Sources
- Foster et al. 2001 — A New Approach to Monitoring Exercise Training
- Alexiou & Coutts 2008 — A Comparison of Methods Used for Quantifying Internal Training Load
- Gabbett 2016 — The Training-Injury Prevention Paradox
Frequently Asked Questions
When should I record session RPE for most accurate results?
Foster et al. (2001) specified collecting sRPE 30 minutes after session completion. This delay allows the acute perception of any single high-intensity interval to normalize and provides a more accurate whole-session gestalt. RPE collected immediately post-session tends to be inflated by the final effort.
How is training monotony calculated, and why does it matter?
Monotony = weekly mean daily load divided by the weekly standard deviation of daily loads. Low standard deviation (similar sessions every day) produces high monotony. Values above 2.0 indicate the athlete has insufficient variation, which is associated with overreaching and illness susceptibility regardless of absolute load level. Hard-easy alternation is the structural solution.
How does sRPE compare to heart rate-based load measures?
Alexiou & Coutts (2008 — PMID 18685606) found sRPE correlated well with heart rate-based methods (TRIMP: r=0.86-0.88) for team sport athletes. sRPE has the advantage of capturing psychological and neuromuscular load that heart rate does not reflect — a mentally taxing session at low HR still registers as high sRPE. Both methods have utility; sRPE is lower cost and captures internal load more broadly.
What counts as excessive weekly load in the strain metric?
Strain thresholds are highly individual and sport-specific. As a rule: strain = weekly load × monotony. A moderate week of 2000 AU with monotony 1.5 produces strain of 3000 — acceptable. The same 2000 AU load with monotony 2.5 produces strain of 5000 — elevated risk. The monotony component is often more important than total load alone.
Can sRPE track technical sessions and not just conditioning?
Yes, and this is one of its key advantages. A technically demanding skill session, a difficult mental preparation session, or a high-volume physical therapy protocol all register in sRPE where heart rate metrics would show low values. For multi-modal athletes, sRPE provides the most comprehensive load picture.