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.

The Right Amount Of Training Time For Single Sport Kids

Most parents and coaches have heard of the growing problem of overuse injuries in youth sports but few are probably aware of the startling statistics.  In the U.S. alone, high school athletes account for an estimated 2 million sports-related injuries every year, while athletes under the age of 14 suffer 3.5 million sports injuries. 

Unfortunately, the U.S. CDC estimates that almost half of these injuries are preventable and occur because of overuse of the same muscles or bones by kids who are specializing in a single sport.  Now, an update to a long-term research study confirms the need to better monitor the type and amount of training for young athletes.

Dr. Neeru Jayanthi, associate professor and medical director at Loyola University, sees quite a few middle and high school athletes at the Loyola sports medicine clinics in Chicago.  Back in 2010, he designed a long-term research program to monitor the types of athletes and injuries that the clinic was treating.  Since then, Jayanthi and his colleagues have enrolled 1,206 athletes between the ages of 8 and 18 into the study and will be following each one for up to three years.

In an April update, he reported that there had been 859 total injuries, of which 564 were diagnosed as overuse injuries with 139 of those being considered serious that kept the athlete sidelined for one to six months or longer.

Along with their health, the team also kept track of each athletes training schedule as reported by their parents.  Combining this data with the injury report, an eye-catching statistic jumped out at them. Those young athletes who spent more hours per week training or competing than their age, in a single sport, were 70% more likely to pick up a serious overuse injury.  So, for example, if a 14 year old soccer player spent more than 14 hours per week in just soccer, they suffered an injury rate over two thirds higher than those players who practiced less than their age.

"We should be cautious about intense specialization in one sport before and during adolescence,” Jayanthi said. “Among the recommendations we can make, based on our findings, is that young athletes should not spend more hours per week in organized sports than their ages.”

Not only is the amount of hours or practice vital but also the balance between organized, structured training versus just free play like pick-up games.  The latest research showed that if this ratio of structured to unstructured time exceeded 2:1, the injury rate went up significantly.

The medical evidence has become so overwhelming that a group of leading medical authorities, including the American Academy of Orthopaedic Surgeons and the National Athletic Trainers Association, have mounted a campaign called Stop Sports Injuries to make athletes, parents and coaches aware of the dangers of early sport specialization and overtraining (see video below).

“Kids often receive pressure from their parents or coaches to be the best in one given sport, when in reality participating in free play and a multitude of sports from an early age is the best strategy to create an outstanding athlete,” said William Levine, MD, Chair of the STOP Sports Injuries Advisory Committee.

Keeping track of an athlete’s training sessions is critical to prevent crossing the threshold to overuse.  Using an online training diary system is strongly recommended to log not only the hours but also the type of activity, the body’s reaction and recovery and the progress of results over time.  Coaches and clubs can also use the diary system to monitor entire teams and player populations enrolled in long-term athletic development plans.