Physical Performance and 3D Shoulder Kinematics of Asymptomatic Unilateral/Bilateral Overhead Athletes and Non-athletes

Study Overview
=================
Brief Summary
-----------------
This study compares the performance and 3-dimensional shoulder kinematics between sides in unilateral overhead-throwers (volleyball attackers), bilateral overhead athletes (swimmers) and non-athletes during two physical performance measures of the upper extremity, one in an open kinetic chain position (unilateral seated shot put test) and the other in a closed kinetic chain position (upper quarter Y balance test)

Detailed Description
-----------------
3-dimensional shoulder kinematics (e.g., scapular angular position/displacement) at key events of each test will be described and compared across sides and groups. For the unilateral seated shot put test, the events are based on humeral motion: a) initiation of humeral motion, b) maximal humeral flexion, c) end of humeral motion. For the upper quarter Y balance test the events are the a) initiation of free hand motion on GO, b) maximal reach on the medial direction, c) maximal reach on superolateral direction, and d) maximal reach on the inferolateral direction (kinematics measured on the stance upper extremity). The best of 3 maximal-effort trials on each side will be used for analysis. Warm-up exercises and two submaximal practice trials will be performed for preparation for maximal efforts and familiarization with the tests. A rest period of at least one minute between trials will be given to guarantee good physiological conditions to maximally perform. Further resting time will be allowed, if necessary, upon request of the participant.

Official Title
-----------------
Physical Performance and 3D Shoulder Kinematics of Asymptomatic Unilateral/Bilateral Overhead Athletes and Non-athletes

Conditions
-----------------
Shoulder Pain

Intervention / Treatment
-----------------
* Behavioral: Chronic exposure to unilateral overhead sports activity
* Behavioral: Chronic exposure to bilateral overhead sports activity
* Behavioral: Not exposed


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Perform at least 150 degrees of arm elevation Exclusion Criteria: history of shoulder dislocation surgery in the upper extremity ≥ 6 months injury in the past month evident abnormalities in posture and movement of the upper body quadrant pain at the time of testing

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Unilateral overhead throwing athletes<br>Volleyball attackers involved in competitive events ≥ 2 years, ≥18 years of age | Behavioral: Chronic exposure to unilateral overhead sports activity<br>* Overhead sports athletes that have been chronically exposed (≥ 2 years) predominantly to specific unilateral overhead movement patterns of the dominant extremity (throwing arm), such as throwing or hitting a ball (asymmetrical overhead sports).<br>|
| Bilateral overhead athletes<br>Swimmers involved in competitive events ≥ 2 years, ≥18 years of age | Behavioral: Chronic exposure to bilateral overhead sports activity<br>* Overhead sports athletes that have been chronically exposed (≥ 2 years) predominantly to bilateral overhead movement patterns of the upper extremities, such as swimmers (symmetrical overhead sports).<br>|
| Non-athletes<br>Persons not regularly involved in sports activities or occupational overhead tasks (e.g. construction workers), ≥18 years of age | Behavioral: Not exposed<br>* People not engaged in regular sports competition/exercise training.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Side-to-side differences in the unilateral seated shot put test (normalized distance thrown, in centimeters) | The unilateral seated shot put test consists of pushing (not throwing) at shoulder height a  3kg medicine ball as far and forward as possible while keeping the axial skeleton in contact with a wall, knees bent at a right angle, feet flat on the floor, and the non-testing arm resting on the lap. | Through study completion, an average of 1 year | 
| Side-to-side differences in the upper quarter Y balance test (normalized maximal distance reached in each direction, in centimeters) | The upper quarter Y balance test is performed through the assistance of a testing device (Y-Balance Test Kit), with the subject stabilizing his/her body weight with the upper extremity being tested while performing maximal reaching efforts with the free hand in three directions: medial, superolateral, and inferolateral. | Through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Side-to-side differences in 3-dimensional scapular angular displacement (in degrees) | The angular displacement of the scapula in the 3 planes of orientation: lateral/medial (upward/downward) rotation, protraction/retraction (internal/external rotation), anterior/posterior tilting. | Through study completion, an average of 1 year | 
| Side-to-side differences in 3-dimensional humerus angular displacement (in degrees) | The angular displacement of the humerus in the 3 planes of orientation: plane of elevation, elevation/depression, axial rotation. | Through study completion, an average of 1 year | 
| Side-to-side differences in 3-dimensional thoracic angular displacement (in degrees) | The angular displacement of the thorax in the 3 planes of orientation: flexion/extension, lateral rotation (inclination), axial rotation. | Through study completion, an average of 1 year | 
| Side-to-side differences in the upper quarter Y balance test (total excursion, in centimeters) | total excursion = sum of the 3 normalized reach distances, in centimeters | Through study completion, an average of 1 year | 
| Side-to-side differences in the upper quarter Y balance test (overall performance score, in centimeters) | overall performance or composite score = average score of the 3 normalized reach distances, in centimeters. | Through study completion, an average of 1 year |