Right arm begins to extend backward and left arm comes forward. Head stays down for the first 15-20 meters and gradually lifts, in this case it is up. Left leg begins to extend and prepares to strike the ground. The right leg begins to flex at the right hip and knee and is brought upward. Make sure to run "on your toes".
Shoulder Girdle- Scapulothoracic protraction (abduction) by the pectoralis minor, serratus anterior, and subclavius begins to occur on the left side.
Scapulothoracic retraction (adduction) by the rhomboids and middle/lower fibers of the trapezius begins to occur on the right side.
Scapulothoracic Elevation/Upward Rotation by the levator scapulae, serratus anterior, upper and middle trapezius, and rhomboids begins to occur on the left side.
Scapulothoracic depression/downward rotation by the pectoralis minor and lower trapezius muscles begins to occur on the right side.
Shoulder Joint Movements and Muscles- Glenohumeral joint begins to be concentrically contracted through flexion in left arm by anterior deltoid and upper pectoralis major muscles.
Glenohumeral joint begins to be concentrically contracted through extension in the right arm by the latissimus dorsi, teres major, lower pectoralis major, and posterior deltoid.
Elbow- The left radioulnar joint begins to flex and is concentrically contracted through the elbow flexors which include the biceps brachii, brachialis, and brachioradialis.
The right radioulnar joint begins to extend and is concentrically contracted by the elbow extensors which includes the triceps brachii and anconeus.
Hip- The right hip begins to flex and is concentrically contracted through the hip flexors which includes the iliacus, psoas major and minor, rectus femoris, sartorius, pectineus, adductor brevis, adductor longus, and gluteus minimus.
The left hip begins to extend and concentrically contracts through the hip extensors which includes the biceps femoris, semi-tendinosus, semi-membranosus, and the gluteus maximus.
Knee- The left knee begins to extend and concentrically contracts through the biceps femoris, semi-tendinosus, semi-membranosus, and popliteus.
The right knee begins to flex and concentrically contracts through the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.