This is an observational study that assess the baseball pitchers' fatigue status. The purpose of this study is to find the pitching mechanic change and the fatigue point to provide guidance for coaches to schedule training items . It is expected that earlier detect the pitchers' fatigue point could be able to prevent overuse injury caused by compensatory actions.

The expected outcomes of this study include providing more reliable scientific evidence of the effects of fatigue on baseball players' performance and movement control, which can help to improve muscle endurance and the quality of movement control. Moreover, fatigue that resulted from the prolonged practice can be reduced and recovered faster after exercise, as well as more understanding on the ideal pitching posture and compensatory action that caused by fatigue, providing a guideline for exercise training. This will not only help to prevent fatigue and reduce risk of injury, but also strengthen weak muscle groups and improve movement strategies before matches, as well as lengthen the time of being a baseball player.

Inclusion Criteria:

• healthy baseball pitchers
• age between 18~35 years old

Exclusion Criteria:

• surgery history in pitching arm
• Musculoskeletal disease
• Neuromuscular disease

baseball pichers