Biomechanics of the overhead throwing motion

The throwing motion is a complex movement pattern that requires flexibility, muscular strength, coordination, synchronicity of muscular firing, and neuromuscular efficiency. During the act of throwing, excessively high stresses are generated at the shoulder joint because of the unnatural movements frequently performed by the throwing. The thrower's shoulder must be flexible enough to allow the excessive external rotation required to throw a baseball. The overhead throwing motion places tremendous demands on the shoulder joint complex musculature to produce functional stability. The surrounding musculature must be strong enough to assist in arm acceleration but must exhibit neuromuscular efficiency to produce dynamic functional stability. During the act of pitching, the angular velocity at the shoulder joint exceeds 7,000 degrees per second and has been referred to as the fastest human movement. Tremendous forces are generated at the shoulder joint, at times up to one times body weight. Because of these tremendous demands, at incredible angular velocities, various shoulder injuries may occur. An understanding of the biomechanics of throwing will assist the clinician in the recognition of various injuries and their specific treatment approaches. In this paper, we discuss the biomechanics of the overhead throwing motion for baseball as well as football.