MEGAN FLYNN, PT & DPT.
In the running world, the most common way to measure training load is how many miles per week an athlete is doing. While running distance is an important factor, it only accounts for one aspect of training stress. It can actually be a poor representation, and an underestimation, of training stress.
When determining training stress, both external and internal factors should be considered to get a true measure of training load and avoid overtraining. Examples of external factors include running distance, running intensity, and frequency of runs. On the other hand, internal factors include psychological and physiological responses to the external load (i.e. rates of perceived exertion [RPE], heart rate, blood lactate threshold). In addition, daily stressors and non-training factors (i.e. work, family/relationships, sleep, financial stress) must be incorporated into the overall training load to get an accurate measure.
Limiting the training load to solely external factors does not take into account how the athlete feels during the session. How much sleep did they get the night before? Is the athlete starting on an empty tank due to an illness? Combining internal and external factors provides a more complete quantification of training stress.
One of the most practical ways to add internal factors to the equation is by using the Rate of Perceived Exertion (RPE). RPE is a subjective rating of intensity and uses a scale ranging from one to ten, with one being the easiest and ten being the hardest. This number should reflect on how you felt during the workout.
You can use a daily mileage, minutes ran, and a daily RPE rating to determine daily training load with either of the following equations:
Daily Training Load = (# of miles run) x (daily RPE)
-OR-
Daily Training Load = (# of minutes run) x (RPE)
You can use this equation to figure out your weekly training load by adding the days of the week together. Track to see if you made a big jump, if you are maintaining a training load, or if you have a true recovery week. You’ll start to notice trends after doing this for a few weeks.
This is a more accurate depiction of your training load because it includes factors other than mileage. It can also help you to make sense of those weeks when your body feels run down and fatigued even though you didn’t have a recent increase in training or mileage.
Give this method a try and see if you recognize any patterns with your training and stress on your body!
Paquette, M. R., Ph.D., Napier, C., PT, Ph.D., Willy, R. W., PT, Ph.D., & Stellingwerff, T., Ph.D. (October 2020). Moving Beyond Weekly “Distance”: Optimizing Quantification of Training Load in Runners. Journal of Orthopaedic & Sports Physical Therapy, 50(10), 564-569.