Group Training Culture
Session RPE: how to measure a class's training load with one question
Session RPE measures how hard a training session was with one question asked afterwards: how was your workout? The answer, on a 0–10 scale, is multiplied by the session's length in minutes. The product is a training load, a single number for the total stress the session placed on that person. In studies of team-sport and endurance athletes, this score rises and falls with heart-rate-based load, and it can also be used for sessions where heart rate is a weak guide, such as heavy lifting. For a gym, it is a cheap way to see how hard each member's week actually was.
Internal and external load
External load is the work done: distance, weight, rounds. Internal load is the body's response to that work, which depends on fitness, fatigue, sleep and heat. The same workout can be light for one member and hard for another.
Heart rate and perceived effort both measure internal load. Heart rate records the cardiovascular response second by second. Session RPE asks the person to sum up the whole session, including what heart rate misses, such as the muscular strain of a heavy squat set.
How the method works
Foster and colleagues described the method in 2001. About 30 minutes after the session, the athlete sees a modified CR-10 scale, Borg's 0–10 rating scale with verbal labels, and rates the session as a whole.
| Rating | Label |
|---|---|
| 0 | Rest |
| 1 | Very, very easy |
| 2 | Easy |
| 3 | Moderate |
| 4 | Somewhat hard |
| 5 | Hard |
| 7 | Very hard |
| 10 | Maximal |
Ratings 6, 8 and 9 have no label. The load is the rating multiplied by the minutes, in arbitrary units (AU): a 50-minute class rated 6 gives 300 AU. The number means little on its own and becomes useful when one person's sessions are compared over weeks.
Foster's group waited 30 minutes so that a very hard or very easy final segment would not dominate the rating. Later work suggests timing matters less than assumed. Christen and colleagues (2016) found no significant difference between ratings collected from 5 minutes to 24 hours after cycling sessions in 15 well-trained adults. In a 2023 study of 25 athletes from four sports, ratings given immediately after hard sessions differed from those given at 30 minutes, while easy and moderate sessions were unaffected. Asking after the cool-down, at least five minutes after the last hard effort, fits both findings.
How well it agrees with heart rate
The 2001 study followed 12 recreational cyclists in steady and interval rides and 14 collegiate basketball players in practices and games. It compared session RPE with the summated heart-rate zone method, proposed by Edwards, which multiplies the minutes in five heart-rate zones by factors from 1 to 5. The two scores moved together consistently, but session RPE always produced the larger number. The authors concluded that the methods carry similar information but are not interchangeable.
Impellizzeri and colleagues (2004) analysed 479 sessions of 19 soccer players aged about 18. For each player, session RPE correlated with three heart-rate methods, with coefficients from 0.50 to 0.85: a clear relationship, not an identical measurement.
A 2017 review by Haddad and colleagues gathered 36 validity and reliability studies across sports, sexes, ages and levels, and judged the method valid and reliable. Correlations with heart-rate load ranged from about 0.1–0.2 in adolescent taekwondo to above 0.9 in fencing and tennis. Stop-start and strength-based sessions tend to agree less, partly because heart rate reflects their effort poorly. Foster's group noted the same for weight training, plyometrics and short intervals, which is why heart rate during strength work needs careful reading.
These studies involved athletes, mostly young and trained. Mixed-ability gym classes have not been studied this way, so accuracy for beginners is an assumption.
Example: one class, two load scores
This is an illustration, not a prescription. A member's saved 50-minute session shows the time below. Pulz8's default zones use the same percentage-of-maximum bands as Edwards's method, so the breakdown converts by hand.
| Zone | % of maximum | Minutes | Factor | Score |
|---|---|---|---|---|
| Z1 | 50–60% | 8 | 1 | 8 |
| Z2 | 60–70% | 10 | 2 | 20 |
| Z3 | 70–80% | 14 | 3 | 42 |
| Z4 | 80–90% | 12 | 4 | 48 |
| Z5 | 90% and above | 6 | 5 | 30 |
| Total | 50 | 148 |
The member rates the class 6, so session RPE gives 6 × 50 = 300 AU. The two totals are on different scales and should not be compared directly. What matters is whether they move together. If this class usually produces about 300 AU and 150 heart-rate points, and one week the rating jumps to 400 while heart-rate load stays near 150, the member found the same cardiovascular work much harder. Poor sleep, an oncoming cold, heat or heavy strength work earlier in the week are plausible reasons, and a short conversation will say more than either number.
Monotony and strain
Foster (1998) combined daily loads into two weekly measures. Monotony is the average daily load divided by its standard deviation, with rest days counted as zero; it is high when every day carries a similar load. Strain is the weekly load multiplied by monotony.
Two weeks with the same total of 970 AU illustrate the difference:
- Varied week: 300, 0, 200, 0, 350, 120 and 0 AU. Monotony is about 1 and strain just under 1,000.
- Uniform week: 150, 130, 140, 150, 130, 140 and 130 AU. Monotony is about 15–17 and strain about 15,000–16,000, depending on how the standard deviation is calculated.
Among the 25 experienced athletes in Foster's study, many minor illnesses occurred when individuals exceeded training thresholds identified for each of them, mostly thresholds of strain. This is an association in a small group with individual thresholds, so it gives no universal cut-off. The practical message is modest: a mix of hard and easy days is easier to monitor, and possibly to tolerate, than daily sessions of similar difficulty.
What shifts the rating
The Haddad review lists many influences on perceived effort, including temperature, music, caffeine, mood, personality and the presence of other people. Caffeine, for example, lowers perceived effort without lowering heart rate. Because the scale is personal, ratings compare well within one person and poorly between people: a 5 from one member and a 7 from another does not show who worked harder.
The review also reports weak agreement between the effort coaches plan and the effort athletes report. In one swimming study, athletes rated hard sessions harder and easy sessions easier than intended. Writing a target rating on the class plan shows whether the class delivered the intended stimulus.
Key points
- Ask one question after class, "How was your workout?", on the 0–10 scale, at least five minutes after the last hard effort.
- Multiply the rating by the minutes to get the session load.
- Collect ratings individually, on paper or a phone, so that other members' answers do not sway them.
- Compare each member with their own history, not with other members.
- Write a target rating on the class plan and check how far members' ratings differ from it.
- Read heart-rate time in zone alongside the rating, and ask questions when the two diverge.
Sources
- Foster C, Florhaug JA, Franklin J, et al. A new approach to monitoring exercise training. Journal of Strength and Conditioning Research, 2001.
- Impellizzeri FM, Rampinini E, Coutts AJ, Sassi A, Marcora SM. Use of RPE-based training load in soccer. Medicine & Science in Sports & Exercise, 2004.
- 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.
- Foster C. Monitoring training in athletes with reference to overtraining syndrome. Medicine & Science in Sports & Exercise, 1998.
- Christen J, Foster C, Porcari JP, Mikat RP. Temporal robustness of the session rating of perceived exertion. International Journal of Sports Physiology and Performance, 2016.
- Rodríguez-Marroyo JA, Blanco P, Foster C, Villa JG, Carballo-Leyenda B. Expanding knowledge about the effect of measurement time on session rating of perceived exertion. Journal of Strength and Conditioning Research, 2023.
Heart rate and perceived effort are training signals, not medical advice. If unusual fatigue or breathlessness persists, or you have a heart condition, talk to a doctor before continuing to train.