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The subjects of this study were high school baseball team players who had consent from April 2017 to June 2017 out of the top 32 schools in the Saitama prefecture high school baseball championship last year. Exclusion criteria were those with injuries during treatment. All players were randomized due to the risk of team-based practice affecting the results. Randomization was achieved using the envelope method. The randomized procedure was performed by drawing a sealed opaque envelope and drawing a sealed opaque envelope containing that specific assignment group (intervention or control group). The number of envelopes, including assigned groups, has been adjusted to match the number of players. The procedure was took in June 2017. Even if the target number of subjects was not reached, we decided to conduct the research with the number of subjects that could be collected. There was no significant difference in the characteristics of participants between the two groups.Age, height, weight, period of baseball experience, dominant hands and field position of the participants were recorded by a questionnaire. From September 2017 to March 2018, FMS score, eyes closed single leg stance time, fatigue over the previous week, pitching ball speed and baseball performance were also measured before the intervention, and at 8, 12 and 24 weeks after the intervention in their field. The FMS comprised 7 tasks including deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, trunk stability push-up, rotary stability. Each task was carried out using the standard FMS measurement kit (1.2 m bar, 2 of 60 cm bar, 5 x 15 cm box). Seven movement tasks were scored with a maximum of three points per task. For balance ability, single leg stance time of dominant leg was measured with eyes closed (the right foot when right pitching). During this test, hip and knee joints were set at 90 degrees on elevated leg with barefoot of standing leg and both upper extremities attached to the body side. During the measurement, the time was recorded at the point the subject could no longer hold the upper and lower extremity and the test was repeated twice with the maximum value recorded. Next, fatigue in the previous week was measured on 11 point numerical rating scale (NRS) anchored at 0 as no fatigue and 10 maximum possible level of fatigue. Pitching ball speed and control were used to evaluate baseball performance using each player's preferred method of pitching. The pitching protocol was set to 3 and 20 fastball pitches at maximum effort toward the simulated strike zone at the official distance of 18.44m. We recorded the fastest ball velocity from 3 pitches using speed gun (SR3600; Sports Radar Ltd., Homosassa, FL, USA), the number of strikes out of the 20 pitches and pitches that were less than 70% of the maximum speed value were not included. The measurement commenced after the participants performed a preparation routine of stretching and warm-up throwing. In the control group, all players practiced normally and there was no limit on voluntary baseball training. In the intervention group, FMS training for tasks that were scored at 2 points or less in the FMS was carried out 4 times per week for 12 weeks from September 2017 to November 2017. Following this, normal activity without performing FMS training continued for 12 weeks as the follow-up period after the initial 12 week intervention. FMS training for 15 minutes a day was conducted after practice and before cool down. However, due to the lack of specialized equipment in high schools, we adopted training that could be implemented with simple equipment such as towels, cushions and sticks as used in previous studies, and according to the official website of FMS. The training was set based on the result of each player's FMS score. In addition, The researcher demonstrated the FMS training program using a video recording. Players were asked to record relevant data daily during the investigation. In addition, a representative was elected at each high school, who was tasked to ensure that data was properly recorded and who checked the implementation at least once every two weeks. FMS training compliance was calculated by dividing the actual FMS training date by the planned period of date. All physical function assessments were performed by the research team and the measurers were blinded. Approval to participate in this research was sought from the principal and coach of each high school. All players were provided with written information about the research prior to obtaining consent. After confirming that they understood the research, approval was sought from the player’s parents with a signed consent form. The study was approved by our institutional review board, the Ethics Committee at the Faculty of Health and Medical Care, Saitama Medical University, Japan (M-75). Registered as a trial registration at the University hospital Medical Information Network Center, Tokyo, Japan