Starting in athletic position, or the ‘start phase’, ankles are slightly dorsiflexed, knees flexed slightly, hips are flexed, and both the lumbar and cervical spine are extended. Shoulders are abducted at a ninety degree angle, and the shoulder girdle has slight upward rotation; the radioulnar joint is pronated, while the wrist and fingers are extended. All motions in the first phase are done bilaterally. While in the first phase, the great toe and lesser toes are both in the flexed position. The flexor hallucis longus is isometrically contracting the great toe while the flexor digitorium longus isometrically contracts the lesser toes. The muscles performing dorsiflexion in the ankle are the antagonist muscles including the gastrocnemius and soleus. This is an isometric movement in the sagittal plane. (Floyd 303) The knee is slightly flexed at about a thirty degree angle. The primary muscles used for this movement are the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. This constant movement is also an isometric contraction performed by the antagonist muscle group in the sagittal plane. (Floyd 278) The hip is flexed and the biceps femoris, semitendinosis, semimembranosis, and the gluteus maximus isometrically contracting. Both, the lumbar and cervical spine are held in anatomical position mainly by the erector spinae. (Prentice 734) The shoulder is
Bibliography: Floyd, R.T, Manual of Structure Kinesiology; copyright 2007. Boston Burr Ridge, IL; McGraw-Hill. Netter, Frank H., Atlas of Human Anatomy Fifth Edition; 2011. Philadelphia, PA; Saunders Elsvier. Prentice, William E., Principals of Athletic Training; copyright 2011. New York, NY;McGraw-Hill.