The contralateral leg- what’s it doing?
So you have injured your right knee, ankle, or foot, but it’s the opposite foot that ‘rolls in more’ or
the left hip that drops rapidly. How does the affect the injury on the side that’s actually injured- and
did that biomechanical issue contribute to the injury?
There have been some interesting studies over the years on the complex world of biomechanics. You
would think by now that 3d imaging, schools of biomechanics, physio, podiatry and exercise
physiologists would have done enough research that the little twist here and the slight restriction
there has caused the injury over there.
Unfortunately the body is amazing complex and I try to give you the information to self-assess as
only you can feel, well what you’re feeling!
So as we run, studies suggest that the hips, core etc. are in control of the foot for MOST of the time
throughout gait (running). So subtle changes at this level can certainly influence mechanics and
injuries at a foot level. Not to say that the foot does not in any way influence the other way, there is
plenty of research suggesting this with many chicken or egg type scenarios.
One thing that I find very interesting and the reason I assess full running mechanics with all injuries is
the opposing limb function in swing (the foot that isn’t on the ground). Let’s make it easy and take
your right foot, and you have an Achilles injury. Now some theories suggest that a lot of Achilles
injuries are a results of twisting of the tendon (think squeezing a sponge) reducing good spring back
and therefore causing injury. There is therefore the assumption that pronation of the foot, inward
rotation of the shin (Tibia) and the knee and thought are the cause of this excess twisting. But why is
it happening, pronation and rotation are normal movements that happen throughout gait so when
do they become a problem?
Some may say excessive movement (there is too much movement), some say rapid movement (the
movement happens too fast) and some say prolonged movement (the rotation or movement takes
too long). Now let’s say this is occurring on the injured side, more so than the opposite side at a foot
level. BUT, at a hip level the movement is ‘excessive’ in some way at a pelvic level…
If you’re still with me, then think about this. While the foot is rolling in, and the tibia rotating in, the
forces at the thigh are in an outward direction- i.e. the forces higher up have changed as the glut
max is an external rotator (all normally what will happen) So the internal movements at the lower
leg are somewhat controlled and cancelled out by the forces at the thigh.
Now if the opposite side like I said is unstable/poorly controlled then this will make it more difficult
for the injured side to move how it is supposed to. Having instability on the opposite side to the
injury may create a larger, longer or faster movement on the side that is injured- and may in fact be
the cause of injury. The opposite side severely limiting what may be in normal circumstances good
efficient function on the good side (but that is the injured side…)
Who’s completely confused!
Basic terms- your right foot hurts- you display normal function in testing of the right limb but while
running there are prolonged, rapid or bigger movements seen. The opposite side shows weakness,
or poor muscle recruitment and there is poor function around the pelvis and hip. The normal shift of
weight from this limb is delayed as you compensate to get control of it (often seen as one arm stiff
one arm swinging excessively) results in the ‘good side’ having greater forces placed on it and
eventually becoming injured.
Think of that over the course of your long run…or even off the bike when you’re already fatigued.
The take home message is try and be body aware, learn some anatomy or get a proper running
assessment done that includes some anatomy.
Ryan Quintano
Podiatrist I Southern Sports Podiatry
Suite 2 49-51 Eton Street Sutherland NSW 2232
T 9521 7578 | Email: ryan@southernsportspodiatry.com.au