In recent years, the Functional Movement Screen (FMS™) has been used for the prevention of disability. Some studies have reported that corrective exercise to improve FMS score is an effective method of preventing injuries (Bodden et al., 2015; Justin et al., 2017). However, measurement instrument to assess FMS™ are not available in high school's. The purpose of this research is to clarify the effectiveness of corrective exercises without specific FMS measurement instruments on FMS score, physical function, and throwing performance in high school baseball players.

High school baseball players were randomly assigned to two groups; 37 in the training group and 34 in the control group. All subjects were evaluated for FMS score, eyes closed single leg stance time, subjective fatigue, as well as pitching ball speed and control at the beginning of the intervention and at 2-months follow-up. Baseball players in training group conducted the corrective exercises 4 times per week for 2 months.

When comparing the 2 groups group, pitching ball control significantly decreased in the training group compared to prior to the intervention. After 2 months, deep squat, hurdle step, inline lunge, active straight-leg raise, trunk stability pushup, rotary stability, total score of FMS, and pitching ball control showed significant better results in the training group compared to the control group.

Results of this study showed that corrective exercises improved asymmetries, trunk stability, movement pattern, proprioception, total FMS score, and pitching ball control without using special instruments following a 2-months training period. Corrective exercises to improve FMS are effective even in high school baseball players without using special measurement instruments.