Technique > Step Anatomy > STANCE PHASE - MID-STANCE SUBPHASE
In animations below, the blue
leg is in stance phase and the
green leg is in swing phase.
 
 

Frames with grey background
indicate those being
discussed on this page.
 
 

Frames being discussed--
shown in slower motion.
 
 
The Mid-Stance subphase is a period of time in the middle of the stance phase. It beings when the foot of the stance leg first has both heel and toes on the ground (usually before the foot passes under the body), and ends just before the heel of the stance foot begins to rise off the ground. Its main purposes are to support the body, help maintain the body's momentum, and prepare the body for the Propulsion subphase.
 
This subphase has no unique technical elements. It simply connects the elements of the Contact subphase with those of the Propulsion subphase.
 
PROPULSION
 
Torque: Friction between the shoe and the ground continues to translate rotational forces in the area of the hip into a propulsive force. The resulting rearward pressure on the stance leg will sometimes hyperextend the stance knee.
 
Falling: As the stance foot moves behind the body's center of mass, gravity begins to make the torso fall forward.
 
Pushing: As the stance foot moves behind the body's center of mass, the walker can begin to use his calf and foot muscles to begin pushing aft. Such a pushing action, however, is almost certainly not going to begin before the heel of the stance foot begins to rise off the ground--which is, by definition, the next (Propulsion) subphase. If applied prematurely, the pushing force will almost certainly be directed downward resulting only in an unwanted rise in the torso and head.
 
BIOMECHANICS OF THE HIPS
 
hip rotation: The stance hip is moving aft, and is usually leading the stance foot (i.e., the stance hip will pass under the body's center of mass slightly ahead of the stance foot).
 
hip drop: The stance hip will be crossing over the top of the arc created by the straightened stance leg.
 
BIOMECHANICS OF THE LOWER BODY
 
straightened knee: While the stance knee can be bent as soon as the stance leg passes behind the body's center of mass, most race walkers continue to hold the stance knee straightened (or even hyperextended) well past the center of mass. In fact, most top-flite race walkers do not begin to bend the stance knee until some point after the stance heel has begun to lift off the ground (i.e., not until the next subphase).
 
flexion of the quads: If the race walker did not have a straightened stance knee on first contact, or he is not confident of having a straightened stance knee, he may still be using the quads to try to keep the knee straightened. Otherwise, the quads of the stance leg should be relaxed.
 
BIOMECHANICS OF THE UPPER BODY
 
shoulder rotation: If shoulder rotation is used, the location of the swing-side shoulder will generally match the location and motion of the stance-side hip. Accordingly, during this subphase, the swing-side shoulder will be at mid swing and moving aft.
 
shoulder drop: If shoulder drop is used, the shoulder usually arcs lower during its journey forward. Because the swing-side shoulder is now moving aft (tracking the stance leg), the shoulder drop should be minimal.
 

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