Session-RPE Internal Load: Formulas, Monotony, and Practical Collection
A practical guide to measuring internal training load across every sport modality using CR-10 Rating of Perceived Exertion, duration, monotony, and strain.
Why Session-RPE Remains the Universal Internal Load Currency
External tracking tools such as GPS units work well on outdoor pitches, yet they cannot quantify resistance training, swimming, indoor court sessions, or off-feet rehabilitation ergometer blocks on a common scale. Foster's session-RPE (sRPE) method solves this cross-modality gap by multiplying a global session intensity rating (0–10 Borg CR-10 scale) by total session duration in minutes.
Because sRPE reflects how hard an individual athlete's physiology actually worked—accounting for heat, altitude, illness recovery, or tactical stoppages—two players completing the exact same drill can record meaningfully different internal loads. That individualized response makes sRPE indispensable for both elite teams and budget-conscious academies.
- Formula: sRPE Load (Arbitrary Units, AU) = Session CR-10 RPE × Duration (minutes)
- Applies uniformly across pitch, gym, conditioning, competition, and rehab sessions
- Captures physiological cost during static holds, wrestling, and high-resistance gym work
- Requires zero wearable hardware to deploy at scale across large squads
Standardizing Timing and Verbal Anchors for Accurate Ratings
Collection timing heavily influences perceived exertion accuracy. Asking an athlete immediately after a brutal final sprint over-weights the last three minutes of pain; conversely, waiting until the next morning dulls intensity recall. Research protocol recommends capturing sRPE roughly 15 to 30 minutes post-session.
Athletes should submit ratings privately on their phone or tablet without seeing teammates' scores to avoid social bias. Always display the CR-10 descriptors (for example, 3 = Moderate, 5 = Hard, 7 = Very Hard, 10 = Maximal) alongside numbers so youth and senior athletes anchor intensity consistently.
Computing Training Monotony and Training Strain
Weekly total load alone misses a crucial risk factor: repeating the exact same moderate-to-high load every single day with insufficient recovery variation. Foster introduced Training Monotony—calculated as the 7-day mean daily load divided by the 7-day standard deviation of daily load—to quantify day-to-day load variability.
Training Strain multiplies Weekly Total Load by Training Monotony. When both total volume and monotony climb simultaneously—such as intense pre-season camps without dedicated low-load recovery days—strain spikes sharply, signaling heightened risk of illness or non-functional overreaching.
Separating Multi-Session Days and Rehabilitation Blocks
On double-session days (such as morning strength plus afternoon technical practice), collect a separate duration and RPE for each modality rather than forcing one blended rating, then sum the daily AU total inside the AMS. This preserves gym versus field load attribution while keeping daily totals exact.
Include rest days as 0 AU in the 7-day window when calculating weekly mean and standard deviation for monotony; omitting rest days artificially inflates monotony and hides the protective effect of planned recovery days.
Modified Borg CR-10 Reference Anchors and Illustrative Session Outputs
| CR-10 Rating | Intensity Descriptor | 60-Min Session (AU) | 90-Min Session (AU) | Typical Session Context |
|---|---|---|---|---|
| 2 | Easy | 120 AU | 180 AU | Active recovery or mobility flush |
| 3 | Moderate | 180 AU | 270 AU | Technical walkthrough or light aerobic |
| 5 | Hard | 300 AU | 450 AU | Standard tactical team training |
| 7 | Very Hard | 420 AU | 630 AU | High-density conditioning or match play |
| 9 | Very, Very Hard | 540 AU | 810 AU | Peak competitive match or maximal test |
Arbitrary Units (AU) equal CR-10 score multiplied by total session duration in minutes including warm-up and cool-down.
Worked Illustration: Weekly Load, Monotony, and Strain Calculation
Consider an athlete logging seven daily load totals (including one 0 AU rest day) during a heavy training microcycle:
- Daily loads (Mon–Sun): 420, 300, 510, 0, 480, 390, 540 AU. Sum = 2,640 AU.
- 7-day daily mean load = 2,640 / 7 = 377.1 AU.
- Population SD across the 7 daily values ≈ 168.5 AU -> Training Monotony = 377.1 / 168.5 = 2.24.
- Training Strain = Weekly Total Load (2,640) × Monotony (2.24) = 5,914 AU.
Key Takeaway: High monotony (>2.0) combined with elevated strain flags coaches to schedule deeper contrast between hard loading days and recovery days.
Session-RPE Collection Checklist
- Trigger post-session mobile sRPE prompts 15–30 minutes after training ends.
- Collect ratings privately so peer scores never anchor an athlete's response.
- Record exact session duration including warm-up and active cool-down minutes.
- Log gym, field/court, and rehab modalities separately before summing daily AU.
- Include 0 AU rest days in 7-day monotony and strain standard deviation math.
- Educate new athletes quarterly on CR-10 verbal anchors to prevent scale drift.
Frequently Asked Questions
Should warm-up time be included in session-RPE duration?
Yes. Standard Foster protocol counts total active session duration from start of warm-up through cool-down, provided the athlete rates overall session exertion.
What if an athlete forgets to log sRPE until the next day?
Next-day recall is less precise for subtle intensity differences. Automated reminders 20 minutes post-session keep same-day compliance high; if missed, staff can log a verified estimate flagged as delayed.
What monotony value is considered high?
In Foster's original frameworks, sustained monotony above 2.0 indicates limited day-to-day load variation and warrants closer review alongside wellness and strain trends.
Can sRPE replace GPS tracking?
They complement rather than replace each other. sRPE measures internal physiological stress across all modalities, while GPS quantifies external mechanical output such as high-speed running.
Primary References & Standards
- Foster C, Florhaug JA, Franklin J, et al. A new approach to monitoring exercise training. Journal of Strength and Conditioning Research (2001).
- Haddad M, Stylianides G, Djaoui L, Dellal A, Chamari K. Session-RPE method for training load monitoring: validity, ecological usefulness, and influencing factors. Frontiers in Neuroscience (2017).
- Bourdon PC, Cardinale M, Murray A, et al. Monitoring Athlete Training Loads: Consensus Statement. IJSPP (2017).