Kinetics of throwing arm joints and the trunk motion during an overarm distance throw by skilled Japanese elementary school boys

Cross-sectional comparison of the probabilistic structure in the distribution of pitching location among baseball pitchers of different ages

The present study was a cross-sectional comparison of probabilistic structure in the distribution of pitching location among baseball pitchers of various age groups (25 elementary school (ES), 20 junior high school (JH), 15 high school (HS), and 18 college students (CL)). In the results, despite the general age-dependent variations in pitching precision, the difference was reflected not only in error 'size' but also in the 'shape' of error as it was shown by fitting 95% confidence ellipse to the two dimensional distribution of pitch location. While the precision measure as a reflection of trial-by-trial variability of release timing (major axis length of the ellipse) was constant, minor axis length of the ellipse as a reflection of variability in the pitching form of each participant demonstrated significant differences among the groups. In the ES group particularly, the trial-by-trial variability in the trajectory angle of the throwing arm was significantly correlated with the minor axis length; this correlation was far greater than those in older groups. The present study is the first to demonstrate the detailed structure of the variability of pitching location of baseball dependent on age.

Qualitative and Quantitative Assessment of Overarm Throwing in Children With and Without Developmental Coordination Disorder

Background: Children with developmental coordination disorder (DCD) frequently have difficulties performing gross motor skills such as the overarm throw. Our study examines the differences in both qualitative and quantitative characteristics of overarm throwing for accuracy between typically developing (TD) and children with DCD. Methods: A total of 74 children (36 females/38 males) aged between 7 and 11 years, participated in this study. The authors used the Movement Assessment Battery for Children—second edition to assess motor impairment. In total, 37 (50%) met the criteria for DCD. Each participant completed 10 overarm throws for accuracy at a target. The authors assessed movement quality using the component approach (Roberton & Halverson, 1984) and quantity using target accuracy. Results: The analyses revealed significantly lower throwing accuracy in DCD versus TD children. Children with DCD also demonstrated fewer component combinations and lower developmental levels than their TD peers. Finally, product scores tracked with process scores. Discussion: Both qualitative and quantitative measures clearly showed that children with DCD are at a disadvantage in controlling a ball during overarm throwing. They used stability profiles that limited coordination variability. TD participants performed more combinations of higher developmental levels to achieve more accurate throws, suggesting they controlled variability to optimize the accuracy of their throws.