La Marathon 2016: Part 3

In the last post we discussed running dosage, or training. I wanted to add just one more thing: Training = Work + Rest. Ideal training involves adequate rest to allow for recovery from the work you are putting in. There are many opinions about training, and the same is true for biomechanics. There are still many runners who don’t think working on running mechanics is beneficial. Even some of the authors mentioned in the last post believe that runners self-select their best running form and that more miles leads to more efficiency. Well, there is evidence supporting that higher mileage runners are more efficient, but that is kind of a chicken and egg problem. Maybe they’re able to run higher mileage because they’re more efficient? The research into biomechanics, gait, and injury is relatively new, but we have learned a lot already. Over these next two posts we’ll dig a little deeper into biomechanics, with this post focused more on background info and the next more on specifics.

To be clear, there is no single perfect running form that fits everyone. Your structure will partly determine your mechanics, but as we discussed in my first post, it’s much easier to improve your mechanics. Recent research has linked things like core weakness, hip weakness, and high loading rates to many of the most common running injuries. We’ve also learned that “over-pronation” and VMO activation of the quad probably aren’t as important as once thought. New research into biomechanics is coming out weekly and will hopefully translate into decreased injury rates soon.

Using a biomechanical approach, we not only diagnose and treat the painful area, but also address the faulty mechanics that led to the problem. We describe this as ‘Victims and Culprits.’ So although we should treat the painful IT Band since it is the victim, we also need to deal with the culprit which is usually weak hip muscles. The area of pain isn’t necessarily the area that caused that pain. When runners battle a recurring injury, it usually means the real culprit hasn’t been dealt with. And here is the best part of biomechanics: Many of the same movement problems that cause injury also lead to inefficiency. Fixing these problems not only prevents injuries, but can also speed you up!

One significant cause of injuries and inefficiency is over-striding. The farther in front of your body that the foot lands, the more breaking forces act to slow you down. This also increases the loading rate – or the speed that force is being applied to the body. Higher loading rates have been linked to patella-femoral pain syndrome, IT band syndrome, shin splints, stress fractures, and plantar fasciitis. These are 5 of the most common injuries for runners!

Christopher McDougall’s book Born to Run got everyone thinking about feet, shoes, and mechanics a few years ago, but everyone’s focus turned to heel striking versus forefoot striking. While there is a connection between shoe type, foot strike and loading rate, the most important factor is where the foot lands in relation to the body. Farther in front = higher loading rate. Closer to body = lower loading rate.

How do we fix this? That depends on the cause and we’ll address some common ones. Running speed is a simple equation: stride length x stride frequency, or cadence (how many times the feet turn over each minute). Some people have a slow cadence and make up speed with a longer stride. Most elite marathoners have a cadence near 180 steps a minute, while many average runners are closer to 160. While keeping the same pace, we can speed up their cadence which will shorten their stride. Our goal is to get folks to at least 172 steps or 86 strides a minute. Test this on your next run by counting how many times one foot hits the ground in 30 seconds and double that number. If it’s less than 86, try increasing your leg turnover for a minute or two without changing your speed. Re-check every 10 – 15 minutes and correct if needed. Or download a running music app that lets you adjust song tempos to the cadence you choose. Your cadence should gradually improve over a few weeks. If you have a good cadence, but still over-stride, then the most likely cause is from lack of hip extension and/or gluteus maximus strength. Those same 180 cadence elite runners also typically show amazing hip extension and good glute drive. Your goal should be to open your stride behind you, rather than over-reach in front of you. At least 80% of the runners I see for gait analysis have tight hip flexors. Many people know the basic hip flexor stretch, but don’t perform it well. If your low back arches and your pelvis rotates forward, then you’re actually decreasing the stretch. We teach people to perform this stretch in a doorway and rotate the pelvis back, pushing the low back into the door jam. This is a little confusing, but try it on yourself a few times. You’ll know you are doing it right when you feel the stretch in front of your hip. To really loosen this up you need to invest 3 – 5 minutes of stretching each hip flexor daily, 5 – 6 days a week, for at least 10 weeks.Right hip flexor stretch. Use a pole or door jam and push your low back into it while tightening your core and squeezing the glutes on the hip you are stretching.

For the sake of space, we will wrap up this post here. In the next post we’ll continue discussing hip extension and go over some exercises to improve gluteus maximus strength. We will also discuss other forces that act on the body during running, as well as ways to help control those forces. In the meantime, stretch those hip flexors and start working on your cadence!

Thank you for reading and Happy Running!

Kasey Hill, M.D. 

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