Dating back to 2005, research from our laboratory and others from around the world has focused on how improving muscle strength can help runners. The purpose of this article is to provide an overview of the importance of muscle strengthening for injury treatment and prevention to also explain, in part, the scientific side of strengthening.

Let’s start with the physiological response to strengthening. We recently published a study wherein runners with patellofemoral pain syndrome (PFPS: pain under your knee cap) performed 2 simple hip-muscle strengthening exercises everyday for 3 weeks. At the end of the 3-week program, runners had a 43% reduction in pain and a 30% increase in muscle strength. In such a short period of time, improvements in strength are largely attributable to changes in neuromuscular activation of muscles and not to changes in muscle fibre composition. Changes in muscle composition are commonly called hypertrophy: the enlargement in the size of the muscle fibres. Other studies have also shown that after only 10 or 14 days of daily strengthening, the number of nerve fibres that are recruited to activate the muscle is what primarily causes the improvements in strength: more nerves are working and thus more fibres are activated. What this means is that if you stop the exercises after only 2–3 weeks of work, even though your pain might be getting better, you’ll quickly lose all the strength you have gained. It takes approximately 5–6 weeks for the architecture of the muscle to actually change, hypertrophy to begin, and long lasting effects to take place.


There have actually been no studies involving long-distance (recreational or competitive) runners to understand the effects of muscle strengthening on overall performance. So I cannot speak to how these types of exercises will help you reach a personal best time. However, our research was one of the first studies to show that strengthening equates to a reduction in stride-to-stride variability — in other words a more consistent running gait pattern on a step-by-step basis. From a clinical perspective, it is reasonable to assume that restoration of a more consistent and predictable movement pattern, concomitant with increases in muscle strength and reductions in pain, would occur. By getting your key stabilizing muscles stronger, you provide the body with more consistent (less variable) movement pattern. If you are injured, the strengthening equates to an optimal environment to allow for tissue healing and pain-resolution. If you’re not injured, the improved muscle strength will be injury protective since your body is being subjected to a consistent stimulus and knows what to expect each step. We’re currently conducting a large study, funded by the Alberta Heritage Foundation, to continue researching this important topic.


Funny thing … one day back in the 1930s someone simply thought that 3 sets of 10 repetitions sounded like a good idea. Unfortunately, no studies have been conducted to determine if 4 sets of 17 repetitions or maybe even 6 sets of 6 repetitions, as examples, would be better. Regardless, 3 sets of 10 reps is commonly the gold standard and certainly used throughout clinical research. There is also strong evidence that performing strengthening exercises everyday, using lighter resistance, is better than only 2 or 3 times per week. One important principle to keep in mind though: always perform these exercises after a run and never before. These are your key stabilizing muscles and if these exercises are done before the run the risk of injury increases due to fatigue.

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