Background: The incidence rate of elbow injuries has been rising in recent years among professional baseball pitchers. Determining valid screening procedures that allow practitioners to identify pitchers at an increased risk of such injuries is therefore of critical importance.
Purpose: To validate the use of countermovement jump (CMJ) tests as a diagnostic tool for pitcher conditioning.
Study design: Case-control study; Level of evidence, 3.
Methods: More than 500 pitchers at a single professional baseball organization performed preseason CMJ assessments on a force plate before the 2013 to 2018 seasons. Three measurements were extracted from ground-reaction force data during the test: eccentric rate of force development (ERFD), average vertical concentric force (AVCF), and concentric vertical impulse (CVI). Athletic trainers at the organization collected detailed information on elbow and shoulder injury rates as well as workload (pitch count) throughout the rest of the season. Poisson regression models were fit to investigate the dependency of injury rates on CMJ test performance.
Results: ERFD, CVI, and AVCF were all significant predictors of elbow injury risk after accounting for pitcher age, weight, and workload. The analysis identified 3 specific indicators of heightened risk based on the results of a CMJ scan: low ERFD, a combination of low AVCF and high CVI, and a combination of high AVCF and low CVI. In contrast, shoulder injury risk was roughly independent of all 3 CMJ test measurements.
Conclusion: This study supports the hypothesis of the entire kinetic chain's involvement in pitching by establishing a link between CMJ test performance and elbow injury risk in professional baseball pitchers. CMJ assessment may be a powerful addition to injury risk alert and prevention protocols. Pitchers in high-risk groups can be prescribed specific exercise plans to improve movement imbalances.
Keywords: Poisson regression; countermovement jump test; elbow injuries; vertical ground-reaction forces.
Improving Vertical Jump Profiles Through Prescribed Movement Plans.J Strength Cond Res. 2018 Jun;32(6):1619-1626. doi: 10.1519/JSC.0000000000002248. J Strength Cond Res. 2018. PMID: 28930872
Risk Factors for Shoulder and Elbow Injuries in High School Baseball Pitchers: The Role of Preseason Strength and Range of Motion.Am J Sports Med. 2014 Aug;42(8):1993-9. doi: 10.1177/0363546514535070. Epub 2014 Jun 3. Am J Sports Med. 2014. PMID: 24893778
Biomechanical Comparisons Among Fastball, Slider, Curveball, and Changeup Pitch Types and Between Balls and Strikes in Professional Baseball Pitchers.Am J Sports Med. 2017 Dec;45(14):3358-3367. doi: 10.1177/0363546517730052. Epub 2017 Oct 2. Am J Sports Med. 2017. PMID: 28968139
Risk Factors for Baseball-Related Arm Injuries: A Systematic Review.Orthop J Sports Med. 2019 Feb 25;7(2):2325967119825557. doi: 10.1177/2325967119825557. eCollection 2019 Feb. Orthop J Sports Med. 2019. PMID: 30828579 Free PMC article. Review.
Prevention of elbow injuries in youth baseball pitchers.Curr Sports Med Rep. 2009 Sep-Oct;8(5):250-4. doi: 10.1249/JSR.0b013e3181b7ee5f. Curr Sports Med Rep. 2009. PMID: 19741352 Review.