Identify Your Injury Threshold

Post by Jannine Myers

Is it possible that each runner has a definite "injury threshold" - in other words, a maximum number of miles that they can run each week before they run the risk of injuring themselves? Anna and I have discussed this on some of our runs together and we agree that this is probably the case for most runners.

Anna and I swapping thoughts and ideas on one of our runs

I became even more convinced of this after I trialed a couple of different training strategies last year. During my training for the 2011 Okinawa marathon, I suffered a number of injury setbacks due to the high volume of miles I was logging each week. In an attempt to avoid the same thing happening again, I decided to heavily reduce my training workload in preparation for the Portland marathon last October. I not only remained injury-free during my Portland training cycle, but I also managed to finish the marathon just two minutes slower than my Okinawa marathon time.

To further convince myself that running beyond a certain number of miles per week would most certainly predispose me to greater odds of injury, I decided to test our theory once more. In preparation for this year's Okinawa marathon, I followed an intense six-day-a-week training plan that had me averaging between fifty and sixty miles per week (with the Portland training plan, I followed a three-day-a-week training plan that peaked at around forty miles per week).

As I began to ramp up the mileage for this year's Okinawa marathon, I welcomed the endurance and speed gains that quickly resulted from the higher volume of training, but it wasn't long before the first signs of injury appeared. I began to have issues with my right calf muscle, my right hamstring, my right achilles tendon, and my right IT band. Fortunately each of these problem areas were not affected simultaneously, but as they each went through phases of stress and tearing, my training was obviously hindered.

When race day finally arrived, it really wasn't surprising when I hit the wall at around mile twenty one and was forced to run the remaining five miles with terrible cramping down the side of my right leg. Fortunately, my first twenty or so miles had been run at a fairly decent pace, so even though the pain I felt caused a significant reduction in pace, I still managed to finish the marathon just four minutes slower than last year.

In summary, I trained for three marathons, two of which entailed five and six day training weeks with an average weekly volume of 50 to 60 miles, and one of which entailed just three days of training a week with a weekly average of 30 to 35 miles. My times for each of the marathons were within a range of no more than a four minute difference, with my second best time resulting from the heavily reduced Portland training schedule.

I realize this is hardly enough conclusive evidence to support mine and Anna's theory, but many running experts do believe that most runners have an injury threshold. If this is true, then one of the keys to injury prevention would obviously be to stay below your injury threshold. Physical therapist and biomechanist Irene Davis, Ph.D., from the University of Delaware's Running Injury Clinic, says, "Your threshold could be at 10 miles a week, or 100, but once you exceed it, you get injured."

I believe that my injury threshold is probably at 40 to 45 miles per week. I also believe that my body handles the stresses of training much more efficiently when I run every other day and allow a day of recovery between runs. More trial and error will help me to know if my beliefs are valid, but for now, I'm opting to follow a "less is best" approach.

As for the rest of you ladies, until you learn what your injury threshold might be, follow the golden rule with training and build your weekly training mileage by no more than ten percent per week!