How Elbow Injuries Happen

INJURIES ARE THE NUMBER ONE FEAR OF ATHLETES, COACHES AND PARENTS ALIKE. AND FOR GOOD REASON.

HIGH-PROFILE INJURY CASES HAVE HEIGHTENED MEDIA ATTENTION TO THE RISKS THAT PITCHERS FACE WHEN PITCHING.

UNFORUNATELY, THERE ARE A LOT OF MYTHS AND MISCONCEPTIONS SURROUNDING THROWING INJURIES.

A review of our in-house studies and peer-reviewed research lead us to some recommendations. 

But, how do elbow injuries, specifically UCL ruptures, occur? As the forearm lays back in external rotaton, valgus stress pulls the bones in the elbow apart while the UCL stabilizes those bones. Over time, this can cause the UCL to tear and rupture.

From Medscape , we learn:  “During the acceleration phase, valgus stress can exceed 60 Newton meters (Nm), which is significantly higher than the measured strength of the UCL in cadavers.”

If the valgus stress on the elbow exceeds the measured strength of the UCL in cadavers, how does a pitcher not suffer a traumatic arm injury on each pitch?

A study on the Biomechanics of the elbow during baseball pitching by Werner et al., concludes that several muscles in the arm work as dynamic stabilizers to prevent overloading of the UCL.

UNDERSTANDING PITCHING MECHANICS AS COMPLEX ADAPTIVE SYSTEMS

If we understand that elbow valgus stress damages our UCL, we should see to eliminate it, right?

Not necessarily.

Pitching is not a single-input, single-output machine. Reducing one variable that correlates with injury could reduce fastball velocity or impact command—and this is not always in the best interest of the athlete.

Werner examined 37 variables that contributed to elbow valgus stress. The four variables that explained 97% of the variance in pitchers were:

• Shoulder abduction angle at instant of stride foot contact
• Peak shoulder horizontal adduction angular velocity
• Elbow angle at instant of peak valgus torque
• Maximum shoulder external rotation torque