Cycle 3

The right knee and hip is now fully flexed. The left knee and hip is fully extended and the next cycle in which the right leg begins to extend and the left leg flexes is about to begin. The left toes push off the ground to initiate the process of beginning to land on the right foot. The left arm is extended forward and flexed at the shoulder and elbow while the right arm is extended backward at the right shoulder and elbow with still a slight bend in the right elbow.

Shoulder Girdle- Scapulothoracic protraction (abduction) by the pectoralis minor, serratus anterior, and subclavius on the left side.

Scapulothoracic retraction (adduction) by the rhomboids and middle/lower fibers of the trapezius on the right side.

Scapulothoracic Elevation/Upward Rotation by the levator scapulae, serratus anterior, upper and middle trapezius, and rhomboids on the left side.

Scapulothoracic depression/downward rotation by the  pectoralis minor and lower trapezius muscles on the right side.

Shoulder Joint Movements and Muscles- Glenohumeral joint is concentrically contracted through flexion in left arm by anterior deltoid and upper pectoralis major muscles.

Glenohumeral joint is 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 flexes and is concentrically contracted through the elbow flexors which include the biceps brachii, brachialis, and brachioradialis.

The right radioulnar joint extends and is concentrically contracted by the elbow extensors which includes the triceps brachii and anconeus. Although there is still a slight bend in the right elbow, it is still extended by the elbow extensors.

Hip- The right hip is flexed and 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 is extended and concentrically contracts through the hip extensors which includes the biceps femoris, semi-tendinosus, semi-membranosus, and the gluteus maximus.

Knee- The left knee extends and concentrically contracts through the biceps femoris, semi-tendinosus, semi-membranosus, and popliteus.

The right knee flexes and concentrically contracts through the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.