Factors influencing upper extremity tissue characteristics and injury in youth overhead athletes
Date
2017
Authors
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Publisher
University of Delaware
Abstract
Despite previous research and proposed intervention strategies, upper extremity
injuries and surgeries in youth overhead athletes continues to rise. A lack of
knowledge about factors such as age, sport specialization, and overuse
pathomechanics are likely reasons for the continued high injury rate. Incomplete
information about underlying tissue characteristics and insufficient knowledge transfer
from the laboratory to field setting, limits the ability of sports medicine professionals
to fully understand these injuries. The purpose of this study was to investigate how
upper extremity tissue characteristics and injury may differ among those who
participate in separate sports, specialize earlier in their sport, and display various
biomechanical patterns. Musculoskeletal ultrasound allowed measurement of tissue
characteristics, and three-dimensional motion capture techniques examined the
relationship between biomechanical variables and injury history. Biomechanical
angles from high speed, commercially available video cameras were compared with
laboratory data to determine whether clinically applicable tools can identify pitchers
with injury history or higher upper extremity joint loads. Differing from non-overhead
athlete controls, the results of this study indicated that humeral retrotorsion and range
of motion are similar among athletes of various ages. Bilateral soft tissue differences
are only present in collegiate athletes. Sport and degree of specialization did not
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significantly impact tissue characteristics. These findings suggest that overhead sport
participation produces bony adaptations participation before skeletal maturity, whereas
the development of bilateral soft tissue differences occurs later. Three-dimensional
biomechanical analysis accurately differentiated pitchers with and without injury
history. Pitchers with a previous injury presented with limited shoulder abduction at
the point of maximal external rotation. While some two-dimensional techniques were
valid compared to three-dimensional analysis, they did not accurately identify
previous injury. Separating groups based on normative and non-normative pitching
mechanics did not differentiate between pitchers who experienced more upper
extremity joint loading. Based on these findings, clinicians may want to identify
pitchers who drop their arms at maximum external rotation. They should use caution
when examining other biomechanics, as variability in pitching mechanics often
supersedes injury group identification. Clinicians should also promote age specific
intervention programs which specifically address underlying anatomical differences
associated with each population.
Description
Keywords
Biological sciences, Health and environmental sciences, Humeral retrotorsion, Pitching mechanics, Posterior capsule thickness, Sport specialization, Youth sports