The swing drill
The purpose of the swing drill is to learn the sequence of actions executed by the swinging leg. The role of this sequence in efficient running action is described in the page entitled ‘The Mechanics of Efficient Running’. The drill entails practice of the three segments of the swing phase: ankle lift; leg swing; and foot fall, while the body is stationary, supported by the opposite leg. Note that this drill is still experimental.
This version was updated on 2nd Jan 2014 to place greater emphasis on the relationship of the swing to the preceding hip extension that occurs from mid to late stance. The hip extension is produced largely by a sharp contraction of gluteus maximus. Although this powerful contraction of gluteus maximus is not a part of the swing drill, it is worthwhile to discuss it here as it sets the scene for the swing. The timing of this contraction is one of the most crucial features of running. Electromyographic studies (eg Prilutsky and Gregor http://www.ncbi.nlm.nih.gov/pubmed/11507111 ) reveal a strong sharp contraction of gluteus maximus at mid-stance. This contraction pushes the foot against the ground, helping create the peak vertical Ground Reaction Force required to lift the body off stance. The contraction is sustained for a brief period beyond mid-stance, extending the hip, so that by toe-off the foot of the stance leg is trailing behind the torso. The hip flexors are under tension, and reflexive contraction of these hip flexors, especially iliopsoas, helps initiate the swing. Precise timing the gluteus maximus contraction is crucial but it is difficult to achieve this by conscious pushing. However, precise timing of consciously controlled contraction of muscles of the upper limb is easier. The contraction of gluteus maximus can be facilitated by a sharp downward swing of the opposite arm. The action is mediated by Latissimus dorsi, the wide back muscle that is anchored to the thoraco-lumbar fascia at the base of the spine. The oblique pull of Latissimus dorsi tensions the thoraco-lumbar fascia stabilising the pelvis and facilitates the required sharp contraction of the Gluteus maximus on the opposite side (as described in detail in my post of June 3rd 2012 https://canute1.wordpress.com/2012/06/03/mary-keitany-a-muscle-named-lady-dorothy-and-the-future-of-the-womens-marathon/ )
Because this drill is intended only to create the sensation associated with the swing while the other leg provides fixed support, it starts with the active leg extending behind the torso as it would be after completion of the contraction of gluteus maximus. Furthermore, only the arm contralateral to the active leg is moved during the drill, to emphasize the relationship between the motion of contralateral arm and leg. After describing the swing drill we will consider how the swing can be integrated into a full gait cycle within a bounding drill that includes the powerful contraction of gluteus maximus at mid-stance.
Stand with the foot that will become active about 12-15 inches behind the other foot, with the ankle in a neutral position and knees slightly flexed; with weight carried forward but with the heel the of the stationary foot remaining on the ground. The arm on the side which will become active is allowed to hand loosely at the side. The contralateral arm is held with elbow bent and the fingers loosely curled, thumb opposed to tip of index finger, a few inches behind the iliac crest.
Ankle lift (hip and knee flexion.)
Lift the ankle towards the hip by flexing hip and knee. Think of the direction of lift rather than which muscles are engaged. (A hand placed on the hamstring should detect the contraction of the muscle body as the knee flexes; there should be very little activity in the quads; the hip flexion is largely performed by iliopsoas which lies deep in the pelvis.) At the end of the lift, the ankle is a little behind the knee of the supporting leg, and the raised knee is a little forward of mid-thigh of the supporting leg. As the ankle moves up, the contralateral arm on the same side moves forward, close to the body.
While the thigh rises towards horizontal, allow a passive swing of the lower leg forwards with the knee as pivot. The swing stops when the knee still retains about 10 degrees of flexion. (When first learning, allow the lower leg to swing back and forth several times to get the feel of a relaxed swing.) In fact gluteus maximus contracts to arrest and reverse the forward swing of the thigh, but this does not need to be a conscious contraction. As the leg reaches the forward limit of the swing, the contralateral arm rises close to the body bringing the hand to a position just below the breast.
Allow the entire leg to swing back passively from the hip. The knee remains slightly flexed and the ankle is neutral. (When first learning, allow the leg to swing back and forth several times to get the feel of passive fall). The foot should strike the ground lightly beside the foot of the supporting leg. The contralateral arm swings sharply down and back, close to the body, easily but not loosely, as the leg falls.
After foot fall, the foot slides lightly back to the starting a position about 12-15 inches behind the other foot. If you create a feeling of stroking the ground with the foot as it returns to the starting position, this will facilitate the required backwards motion of the foot relative to the COG at foot-strike. The contralateral arm continues its backward motion to the point where the hand is a few inches behind the iliac crest. The down and backwards sweep of the arm is firm and precise, but not as forceful as it would be when running..
At the beginning of each session, perform these three actions as separate, distinct movements, and once you have the correct feel for each action, perform them as a continuous smooth loop.
This drill has some similarities to the tapping drill in Pose, but it is designed to encourage a somewhat longer stride than is typical in Pose, while avoiding over-reaching. In addition, the emphasis on simultaneous arm movement is intended to establish a link in the brain between a compact arm movement and an associated compact leg movement. Because proprioceptive signals from the upper limb are more strongly represented in the brain than signals from the leg, the creation a strong link between leg and arm movement should facilitate monitoring of the swing action while running.
Integration of the swing into the gait cycle
To integrate this relaxed swing with the more dynamic action that occurs during the stance phase of running, it can be helpful to follow the swing drill with several short bursts of bounding for about 20 metres. During bounding, employ a sharp downward movement of arm opposite the stance leg. This facilitates a forceful contraction of gluteus maximus at mid-stance, delivering a push which is augmented by elastic recoil of the quads and propels the torso upwards and forwards while pre-loading iliopsoas. However, focus more on the timing than the forcefulness of this action, and visualise the relaxed swing that will follow. During early swing the major work load is borne by the iliopsoas which contracts without requiring conscious attention. Later, Gluteus maximus will again become active to arrest the swing, but this activation is also automatic provided the visual image is of the foot dropping under the body (but actually a little in front) .
In summary, during bounding, direct attention to the timing of the sharp down swing of the arm opposite the stance leg and visualise the relaxed trajectory of the swinging leg. If you allow the major forceful actions of the large muscles (Gluteus maximus, the quads and iliopsoas) to occur automatically, the timing of these contractions is likely to be more precise.