A basic understanding of running biomechanics is essential for managing a running athlete. In comparison to walking, running increases our speed, reducing our contact time and increasing our flight time. This results in a distinctive stance and swing phase. For stance phase, we further break things down to:
- Initial contact
Initial contact involves the first striking of the foot on the ground, which can influence the whole kinetic chain. Typically, we contact with either our heel, midfoot or forefoot, with heel striking being the most common.
Midstance occurs as the foot starts to move under the body and the bodys' centre of mass moves to it's lowest point.
Propulsion involves push off as the lower limb moves behind the body, resulting in the foot forming a 'rigid lever' for push off. This rigid lever is through the Windlass Mechanism of the Plantar Fascia which is a story for another day.
Through this stance phase our lower limb joints go through several motions and movements. We require smooth motion to occur at our foot, ankle, knee and hip, and should these joints not provide us with the required range of movement, excessive force or movement will be required elsewhere (at another joint).
The foot goes through a transition of supination as it prepares for contact, which is followed by pronation or flattening of the arch, which allows the foot to act as a shock absorber. Through midstance and into propulsion the foot then supinates once more to prepare for a high gear push off.
The ankle dorsiflexes as it prepares for contact and continues to dorsiflex as it moves through midstance, getting to end range dorsiflexion before the heel starts to lift and plantarflexion takes place for push off.
The knee flexes through swing phase and then begins to extend, controlled by the hamstrings as we contact the ground in relative knee extension. The knee flexes through midstance as our centre of mass drops, then extending as our leg moves behind our body for push off. The more our knee bends through midstance the higher the load through our patellofemoral joint.
The hip flexes through swing phase as we get a 'triple flexion' scenario of hip, knee and ankle flexion. The hip moves to flexion for initial contact, and then moves behind us into hip extension for push off, where we get a 'triple extension' scenario of ankle, hip and knee extension.
There's a brief overview of our ideal biomechanics when we run. There are many variations from this and it is certainly worth checking out your own biomechanics with a structured running analysis!