Relationship between a history of disabled throwing shoulder/elbow and the ability to perform the deep squat test among youth baseball players

Aim: The deep squat test (DST) is a screening test to assess the function of the lower extremity and the flexibility of ankle dorsiflexion. Previous study reported that approximately 70% of players with disabled throwing shoulder and/or elbows were unable to perform DST. The aim of this study was to reveal the relationship between performance of DST and history of disabled throwing shoulder/elbow. Methods: A total of 1,439 youth baseball players (10.9 years; range 6–16 years), who participated in pre-season medical examination were included in the study. Players who experienced shoulder or elbow pain of the throwing side during or after playing baseball in the past were defined as players with a history of disabled throwing shoulder/elbow. The DST was evaluated by having the players perform a full squat with while having their arms crossed in front of their chest and their feet apart without lifting the heel off the floor or falling backwards. The relationship between a history of disabled throwing shoulder/elbow and the ability to perform DST was analyzed. Results: Among the study participants, 499 (34.7%) had a history of disabled throwing shoulder/elbow, and 532 players (37.0%) were unable to perform DST. Of the players with disabled throwing shoulder/elbow history, 227 players (45.5%) were unable to perform DST, as were 305 players out of 940 players (32.5%) without a disability; this difference was statistically significant (P