A review of studies on the effects of plyometric or ballistic resistance training on baseball throwing velocity found that: Three studies involving 126 male baseball players ages 11-21 found that plyometric training programs lasting 4-8 weeks significantly increased throwing velocity by 1.5-2.2 mph compared to control groups. Only one subject reported any dissatisfaction with the training programs on questionnaires. Plyometric training can significantly and practically improve throwing velocity for baseball players to aid performance and rehabilitation from shoulder or elbow injuries.