Some quick thoughts today on overstriding in running.
Overstriding in running is common, even in the more elite runners. It’s a hot
topic at the moment with the advent of minimalist running shoes and the
barefoot community pushing their side. Striking mid foot and fore foot has
become the new ‘trend’.
So, how do
we define an overstride?
Overstriding is basically where you land outside your centre of mass, ahead of
your body if you like. There are a couple of things that are usually apparent
with overstriding;
1.
Posterior pelvic
tilt
2.
Heavy heel
strike (as opposed to a light or glancing heel-strike)
3.
Greater knee
extension (meaning more work from the quads)
4.
Larger braking
forces (deceleration)
5.
Considerably
more work from the calves to ‘propel’ the runner
6.
More time on the
ground (slowest portion of the gait cycle)
7.
Slower cadence
With all of this going on it looks to increase your
injury risk profile. It is definitely less efficient and slower in nature. The
key point is how do we recognise this and how do we change this. Does it really matter whether we mid foot or fore foot
strike? Let’s look closer at each point.
Posterior pelvic tilt is one of the most common
things occurring in distance runners with greater prevalence in the more mature
athlete. As soon as this happens your sacrum is thrust into a position known as
‘counter-nutation’ effectively limiting your ability to extend your hips. This
position shuts down the powerful glute and hamstring muscles from their ideal
firing position. The propulsion is therefore gained from quads and calves.
Posterior pelvic positions leave the lumbar spine
vulnerable to loading forces – especially the sacro-iliac joint and discs. The
first thing you need to do is get your pelvis in a neutral to (slight) anterior
tilt, without this it’s very hard for the lower limb and foot to be in a
biomechanically correct position!
Heel striking is not inherently bad, it is more how
you do it rather than if you do it. As you fatigue, heel striking becomes the
preferred position. Even the great Haile Gebrasalasie ran in a glancing heel strike
position towards the end of the marathon. The key point here is to try and keep
your cadence a little shorter, allowing your foot strike to land closer to your
centre of mass. This results in a quicker and lighter foot strike with lower
braking forces and usually a strike that is more toward a mid-foot strike.
Greater knee extension occurs in relation to the
posteriorly rotated pelvic position. Lack of glute and hamstring firing
necessitates increased extension at the knee joint to lengthen the stride,
simultaneously increasing lower extremity loading as the heel strikes the
ground in a straightened (knee extended) position. To change this, you need to
address the pelvic position.
Deceleration (braking) forces occur during heel
strike outside the centre of mass with the foot in a strong dorsiflexed
position. This creates a collision impact with opposing forces as opposed to
the foot contacting the ground in a rotary motion. This rotary motion uses the
ground to propel and push off allowing acceleration to continue through the
full gait cycle. This allows the use of the elastic energy stored in the
myotendinous unit through the stretch-shortening cycle.
With deceleration occurring the calves are forced to
accelerate through mid-stance to toe off over a longer period of time, hence
there will be larger forces acting on the lower limb. Due to the longer contact
times the runner will be slower through their stride (the slowest portion is
the time on the ground, more time on the ground equals slower stride).
Mid foot and fore foot striking is the new ‘trend’. A
foot strike of this kind is not necessarily better. What is important is
whether or not an overstride is present. It is not impossible to have an
overstride with a forefoot strike especially if the runner forces the forefoot
into plantar flexion in the belief that a forefoot strike is better! Deal with
the overstride and let the foot land however it is used too.
With all this occurring it may appear as a long and lengthy
period to correct.
As the body works as a kinetic chain one change can
often alleviate others. Starting with the pelvic position is an obvious choice.
This often helps with a foot strike closer to the centre of mass. Changing the
cadence by as little as 5-10% may also assist by shortening the stride. These
two changes often increase knee flexion angle on foot strike and increase hip
extension.
Overstriding is a common problem that can be
addressed in a step by step fashion. The most important factor is whether you
end up striking close to your centre of mass, not whether you heel strike or
not.
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