Gait is the manner in which we walk, run or jog. Each of us has our own unique gait, with its own variations in tempo, joint kinematics and muscle activation sequences. Analyzing gait has even been used for security identification purposes. You know what I’m referring to if you are a Mission Impossible fan.
Today let’s discuss the two primary support phases of gait. Support simply means some aspect of our foot is in contact with the ground. Early support refers to the point of our gait where our foot has just struck the ground, commonly known as heel strike. Late support, often referred to as toe-off, involves those last few moments right before our toes leave the ground.
Early support is all about shock absorption. Think about it…that leg striking the ground takes on all of your body weight pretty quickly. To make sure we do not crumble to the ground upon heel strike, we have a series of controlled eccentric contractions to offer shock absorption. The bulk of the eccentric work is done by the quadriceps, as our knee goes into flexion. At the ankle, the gastrocnemius-soleus complex eccentrically contracts to make sure we do not go into an excessive amount of dorsiflexion.
As we transition from early support to late support, our lower extremity will go into triple extension as we toe off and propel ourselves forward. Triple extension involves hip extension, knee extension, and ankle plantar flexion. Ideally, our energy expended during late support should be primarily horizontal. Any force produced vertically does aid our endeavor to push forward.
This is a very quick overview of the support phases of gait, but understanding these basics discussed above is a huge step forward in taking your gait analysis skills to the next level.