Stability for Runners – Part 2: Stabilising muscles
By Peter Colagiuri
Stabilising muscles are the silent heroes in the pursuit of running. Working hard, without acknowledgement, to make sure the rest of the system can do its job. But how often do you work on your stabilisers and do you know what exercises can target them best?
If your answer included the words “clams”, “crunches”, “planks” or “sit-ups”, you’ve been fooled by some of the most enduring myths in the running world. The classic approach to core exercises misses the mark, targeting the wrong muscles and out of context without any benefit for the running action.
The primary stabilisers are the muscles optimally positioned to provide stability to a joint during the running gait pattern. Many stabilisers actually contribute to a number of different actions through the gait cycle, which makes it difficult to mimic their complex action with simple exercises.
In the ankle, one of the key players is Tibialis Posterior, responsible for control of the inside edge of the foot and ankle. But it’s not as simple as raising the arch for “Tib Post”; the muscle actually lowers the arch under control after the foot has contacted the ground. It works in conjunction with Peroneus Longus, located on the outside of the ankle but wrapping under the foot to connect to the ball of the big toe. It gives support to the big toe as it works to propel the runner.
If these primary systems aren’t performing, the secondary mechanisms will kick in to cover it. Muscles such as Tibialis Anterior, located on the front of the shin, begin to help but they’re not capable of performing the role as well as the primary muscles and pain and tightness soon follows. Alternatively, Flexor Digitorum Longus (“FDL” to his friends) kicks in to help make the foot rigid but leads to the toes curling over, causing painful and/or black toenails.
Around the hip, the gluteal muscles reign supreme as the key stabilisers. But they’re also some of the main contributors to power generation, and it’s this multi-tasking that can sometimes cause trouble. If the glutes aren’t performing well, the hamstrings will kick in to help with forward drive. But the hamstrings aren’t well placed to assist with power generation in the latter part of the movement, so they fatigue and tighten quickly. Another limitation occurs with over-striding, where the leg lands too far in front of the runner. As the glutes are quite short, they can’t effectively stabilise the hip when they’re at the end of their range. The easiest analogy is to compare it to a chin-up. It’s a lot harder to start this movement when you’re at a full drop (arms straight) instead of starting with your arms slightly bent (aka. cheating). This is because muscles at the end of their length can’t generate anywhere near as much power as they can when they’re in a neutral position.
The trunk is a more complex area, where arms and legs can assist in maintaining stability depending on how fast you’re moving. For distance runners the arm movement is generated by leg movement, not by the muscles in the arms. For sprinters, the arms create a lot of drive and their movement is powered by the arm muscles. That’s why Usain Bolt has muscular arms and Mo Farah does not.
With the arms generating a lot of the rotational stability of the trunk in distance running, the abdominal and back muscles don’t have to work as hard. For sprinters, strong abdominal and back muscles are necessary to transfer the force generated by the arms down into the legs. But it’s a rotational force, so classic core exercises like sit-ups, planks and crunches that target the ol’ six-pack (a muscle called Rectus Abdominus) aren’t overly effective for runners as these exercises don’t have a rotational control component.
In our final instalment of the Stability for Runners series, we’ll cover how to change your stability system with exercises, drills and specific running sessions.
Peter Colagiuri is a Sports Physiotherapist, specialising in running injuries. He practices in Miranda and Manly in addition to researching at the University of Sydney. For more information see bioathletic.com.au, firstname.lastname@example.org or book an appointment (02) 9977 1580.