Cycle 4

The right leg is now extended forward at the hip and knee and has made contact with the ground. The left leg is fully flexed at the knee and is about to be driven forward at the left hip. The right arm is beginning to flex outward and the left arm is extending backward. A full cycle of right and left leg movements have been completed. The landing phase is considered an eccentric contraction everytime the foor strikes the ground. The cycle contiues the same way until the race has ended for your particular event.

Shoulder Girdle- Scapulothoracic protraction (abduction) by the pectoralis minor, serratus anterior, and subclavius on the left side but is in the process of retraction.

Scapulothoracic retraction (adduction) by the rhomboids and middle/lower fibers of the trapezius on the right side but is in the process of protraction.

Scapulothoracic Elevation/Upward Rotation by the levator scapulae, serratus anterior, upper and middle trapezius, and rhomboids on the left side but is in the process of downward rotation.

Scapulothoracic depression/downward rotation by the  pectoralis minor and lower trapezius muscles on the right side but is in the process of upward rotation.

Shoulder Joint Movements and Muscles- Glenohumeral joint is concentrically contracted through extension in the right and left arms at this time by the latissimus dorsi, teres major, lower pectoralis major, and posterior deltoid, however the right glenohumeral joint is preparing to flex forward as the left glenohumeral joint will extend backwards.

Elbow- The left radioulnar joint is still flexed and is concentrically contracted through the elbow flexors which include the biceps brachii, brachialis, and brachioradialis. It is preparing to extend backwards.

The right radioulnar joint is still flexed and is concentrically contracted through the elbow flexors which include the biceps brachii, brachialis, and brachioradialis. It is preparing to flex forwards.

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

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

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