Normative Hip Range of Motion and Strength Profiles of Uninjured Baseball Athletes: A Systematic Review.

Context: The baseball athlete incorporates the use of the entire kinetic chain while throwing. Hip range of motion (ROM) and strength have been previously studied in its relation to injury development. It is a clinical necessity to understand the normative profiles of hip musculoskeletal function across the playing career.

Objectives: To identify the normative hip ROM and strength profiles of baseball players across level of play.

Evidence Acquisition: The researchers searched the electronic databases MEDLINE, SPORTDiscus, CINAHL, and Embase using a custom search strategy. After applying inclusion and exclusion criteria, 31 articles were reviewed. Of these 31 articles, 22 examined hip ROM and/or strength in uninjured baseball athletes. A manual search of the references of those 22 articles revealed 4 additional articles that met the inclusion criteria. In total, 26 articles were included in data collection.

Evidence Synthesis: Articles were assessed for quality using the appraisal tool for cross-sectional studies. The appropriate hip ROM and strength data, along with player demographics, were extracted and reviewed to ensure accuracy. Articles were also categorized based on level of play and player position.

Conclusions: Hip ROM and strength profiles of baseball athletes across all levels of play were identified and presented to comprehensively summarize the available data on normative musculoskeletal hip profiles. Observed differences between positions and across levels of play were documented. In general, hip external rotation ROM was greater than internal rotation across all levels and between the stance and lead limbs. As age and level of play increased, the difference between hip external rotation and internal rotation ROM also increased. Hip strength increased as level of play (and subsequently age) increased. These summarized data can be used as benchmarks to compare clinical populations.