Quantitative Assessment of Developmental Levels in Overarm Throwing

APDM Opal sensors were used in a recent study published in the Journal of Sports Sciences. The study, titled “Quantitative assessment of developmental levels in overarm throwing using wearable inertial sensing technology,” aimed to propose an in-field quantitative approach to identify different developmental levels in overarm throwing in children.

As outlined in the study, motor proficiency in children has been linked to levels of physical activity, and has been recently recognized as a public health determinant. Among the motor development community, ballistic skills assessment was progressively needed.

Researchers took anthropometric data characteristics of fifty-eight 5-10 year-olds, and then placed Opal sensors on three landmarks: Near the wrist of the right forearm, the anterior central surface of the thorax, and the lower lumbar spine. The kids were asked to stand 6 meters from a wall and perform an overarm throwing task using a tennis ball. Three complete executions of the task were recorded, and a video camera was used to record each throw.

A set of temporal and kinematic biomechanical parameters were defined and analyzed based on existing literature in order to determine different overarm throwing developmental levels. Certain phases of a throw were outlined, including a cocking phase, acceleration phase, and a post ball release phase. Specific parameters, such as the angular velocities of the trunk and pelvis and the duration before ball release, were shown to to identify all of the developmental transitions in overarm throwing skill in the children.

Results showed that the duration of the throw cocking phase significantly discriminated the highest developmental level from the other two levels used. An increased throw cocking phase was associated with an increased rotation of the trunk in the vertical axis. Throwing acceleration slightly decreased when moving along the developmental levels, showing that proficient throwers tend to decrease the time required to perform the acceleration phase of a throw.

The study outlines similarities and differences of results compared to previous studies, and identified the advantages of using Opal sensors compared to previous methods such as Video Motion Capture. Typically encumbered by long post-processing times and low accuracy, Video Motion Capture lacks the ease of use, robust design, small dimensions, and freedom that Opals offer researchers.

These results show promise for motor learning experiences in educational and youth sports training settings. They have the potential to be applied to further exploration in the biomechanical analysis of certain sports such as baseball, or for occupational therapy.


For more information on the study, click here. 

For more information on Opal sensors, click here.

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