Lower limb injuries part 1..

One of the most common problems with long distance running is the recurrence of lower limb injuries. By ‘lower limb’ I’m talking about the stuff that goes on below the knee and this includes (but not exclusively):

1. Achilles problems
2. Shin Splints (front or rear)
3. Plantar Fasciitis (pain under the foot / heel)

Overuse injuries are created by repeated action, hence they are common in long distance runners. In some circumstances, runners may have bio-mechanical faults which make them more susceptible to overuse injuries. In other cases, it’s simply a matter of doing too much and the tissues just can’t handle the load. Perhaps the most commonly cited reason for injury in runners in ‘over-pronation’, this describes the action of the foot landing on the outside of the heel and then rolling both forwards and inwards onto the big toe. Pronation has been blamed so frequently for running injuries that we now have specific shoes and various inserts to prevent the action, but is pronation receiving unnecessary criticism?

Pronation explained

The vast majority of runners pronate to some extent when they run. If you stand with your feet hip distance apart and then start walking, you’ll notice that you don’t walk with your feet hip distance apart. It is natural to walk and run with your foot directly underneath the centre line of your body (if you draw a line from your nose, through your belly button and down to the floor, that’s where you foot will land). This means that your leg is always at a slight angle, starting at your hip, the leg angles inwards to the point of foot strike and this means that you are likely to hit with the outside of your heel.

At the point of impact, the force applied to the outside of your heel ‘flips’ your shoe (and your foot) inwards. Stand holding a running show and with your hand, strike the underside of the heel on the outside edge. The blow will flip the shoe inwards, this is what happens to your foot each time you strike the ground.

Injuries linked to pronation

As your foot flips inwards, this triggers the pronation movement. In an attempt to control both the amount and speed of pronation, there are some specific muscles  which take the majority of the strain. The tibialis posterior and anterior muscles run along the length of your shin bone. The anterior muscle is found on the front of your shin and the posterior muscle is found on the inside of the lower leg, behind the shin bone. You can generally find both quite easily with your fingers. The tendons from each pass over the inside of your ankle joint (look at the boney lump on the inside of your ankle, if you move your foot about, you’ll see the tendon moving on the boney lump).

When these 2 muscles contract, they pull up the arch of the foot and turn the ankle so the sole of the foot faces inwards, this is the opposite movement to pronation. Their main job is to control the pronation movement and as the foot rolls inwards, they are pulling back in the opposite direction to reduce and slow the pronation movement. For this reason, if your foot pronates excessively, these muscles have to work extremely hard and this may lead to inflammation of the muscle or the tendon (the tendon is the white part which attaches the muscle to the done). Inflammation of these muscles is commonly referred to as shin splints or potentially ‘compartment syndrome’.

The pronation movement can also lead to achilles problems. Generally the achilles is pretty strong when it pulls in correctly alignment, unfortunately pronation causes the achilles to twist, as if ‘wringing it out’ and this leads to damage and inflammation. Pronation can also lead to flattening of the arch and this applies stress to the tissues which are supporting the arch. one of the main structures supporting the arch is the plantar fascia, a tendon which runs from the underside of the heel bone to the forefoot, splitting into the 5 toes. If stress is applied to the plantar fascia, it can start to pull away from the underside of the heel bone, leading to a sharp pain known as plantar fasciitis.

So pronation is bad.. right?

There are various problems which are ‘potentially associated’ with pronation and these are often treated with a change of shoes or orthotic insert when they may well have been resolved with some rehab (strength and stretch). However, pronation is not a bio-mechnical fault, it is an important part of your running which has simply received a lot of bad press. Before you rush out and buy inserts for your shoes, contrary to what you might think from reading the above information, pronation can be your friend if you know how to handle it.. we’ll look at that in part 2 of the sequel.

Advertisements