I have already talked about the stance phase in a previous post and now it’s time to talk about the swing phase. These two phases show you what your body does when you run; the way your muscles, joints, ligaments, among other structures, work while you don’t even think about what you are doing. Swing phase is part of the running gait cycle which begins when your foot makes contact with the ground, and ends when that same foot makes contact with the ground again. Stance phase begins when your foot makes contact with the ground, and ends when that same foot takes off and the swing face begins when your foot takes off and ends when that foot makes contact with the ground.
To make things clearer, stance phase is when your foot is in contact with the ground and swing phase is when your foot is in the air. Let’s leave the stance phase behind and focus on the swing phase.
Note that your arm movements also play an important role in running, although it is something I will talk about in the future.
It is considered the least important phase, as the risk of injury when the foot is in the air is lower. The swing phase can be divided into different stages, depending on the paper or website you have a look at. I am going to divide it into three stages: initial swing or acceleration, mid-swing and terminal swing or deceleration.
1. Initial swing or acceleration
Initial swing is the initial one-third of the swing period. It begins when the foot leaves the ground until maximum knee flexion occurs. The lower limb (leg) is directly under the body. The hip extends (leg moves backward) and then flexes (leg moves forward) due to the contraction of the iliopsoas muscle (important hip flexor) with external rotation (your leg rotates outward). Your knee flexes (bends) , and the ankle goes from plantar flexion to dorsiflexion.
Mid-swing occurs in the second third of the swing period. This phase begins following maximum knee flexion and ends when the tibia is in a vertical position. The hip flexes more (comparing to initial swing) and the ankle dorsiflexes due to the contraction of the tibialis anterior muscle (muscle located at the front of your shin bone). Your knee flexes (bends) and then extends (straighten) due to the contraction of your quadriceps (important muscle located at the front of your thigh)
3. Terminal swing or deceleration
Terminal swing occurs in the third third of the swing period. Your hip is flexed, your knee in complete extension and your ankle in neutral position ( position when you are standing upright). All these steps are the preparation for heel contact and, therefore, for starting the stance phase again.
Find below a video with your foot movement in the swing phase.
I do understand that this is a very simple way to explain the running gait cycle. The reason is that this is an easy way to understand the basics for those that are not much into running and anatomy yet. Check out this link about the biomechanics of running if you want to find more in-depth information.
Comments are welcome, they are always helpful for everyone.
If you have any questions, do not hesitate to contact me on The Physical Therapy, Physiotherapy Clinic based in Southampton, and I will be happy to help you.