Using Rate Of Perceived Exertion As A Training Metric

Coaches invest hours devising training plans that will push their athletes just to the edge, but not over.  Overtraining leads to burnout and injuries but going easy won’t get the right results.  The challenge of walking this fine line is truly understanding the intensity and workload being placed on athletes, whether its real or perceived.  Objective, wearable technology has helped in the form of heart rate and GPS monitors, but can be expensive and doesn’t capture a true sense of the player’s experience.  As an alternative, sport scientists have recently found that a self-reported rate of perceived exertion (RPE) can accurately capture the workload experience.

Two sports that are learning to rely on RPE, soccer and swimming, represent two very different training styles.  Soccer coaches spend considerable time on team drills and scrimmages while interspersing physical fitness into the sessions.  Swimmers, while part of a team, primarily focus on individual times and skills.  Despite the differences, researchers have found plenty of evidence that the athlete’s opinion of their workout difficulty is valid and reliable.

Back in the 1960s, Gunnar Borg, psychology professor at Stockholm University, created the RPE scale, now respectively called the Borg scale.  The original version asked athletes to rate their level of exertion on a range of 6 to 20, with 6 being “very light” and 20 indicating “very difficult.”  While the 6-20 range may seem an odd choice, it actually has some logic.  Borg found that if the rating is multiplied by 10, there is a high correlation to the athlete’s heart rate at that moment (i.e. a rating of 12 typically corresponds with a HR of 120).

Borg also added a 10 point scale, known as the Category(C) Ratio(R) scale or CR-10.  This produces ratings of 1-10 and is used not only in sports training but also in clinical settings to estimate levels of pain.

Last year, Spanish and Italian researchers compared the workout assessments of 28 semi-pro soccer players.  For an objective measure, they captured heart rate history and tracked their distance travelled with GPS devices.  Then, after each training session, they asked the players for their RPE using the Borg CR-10 scale.  They found a very high correlation between the HR data, the distance travelled and the players’ RPE ratings.

“Being easy to perform and inexpensive compared with HR-based methods, sRPE should be regarded as a viable way to track internal load in training setup in soccer,” concluded David Casamichana, sport scientist at the University of the Basque Country and lead author of the study published in the Journal of Strength and Conditioning Research.

But what if young athletes report a “less than truthful” RPE in an attempt to either impress or fool their coach?  In the same way, what if the coach’s interpretation of a hard workout does not match with a player’s reaction to it?
Renato Barosso, of the School of Physical Education and Sport at the University of São Paulo, Brazil, gathered together 160 swimmers of different age-groups and different competitive swimming experience, and nine of their coaches.  Looking at their training plan for the day, the coaches were asked to rate the workout using the CR-10 RPE scale, prior to the session.  Then, 30 minutes after the training, the swimmers were asked for their RPE to see how well it matched the coaches’ estimates.  Athletes were divided into three age groups, 11-12, 13-14 and 15-16, while the workouts were classified as easy (RPE less than 3), moderate (3-5) or difficult (greater than 5).

As might be expected, the agreement between coach and swimmer was higher for older swimmers and lower for younger swimmers.  While the coach’s estimate of intensity was assumed correct, the researchers found that the swimmers aged 11-14 ratings differed across all three categories, easy-moderate-difficult.  The oldest swimmers only disagreed with their coaches at the difficult level.

So, while RPE can be trusted for an accurate estimate of training difficulty, it would benefit both athlete and coach to gather all available data in one online training system for comparison and analysis.  Being able to chart RPE over time against more objective measures like HR, repetitions or activities would enable better training plans.