Biomechanical Basis of Interval Throwing Programs for Baseball Pitchers: A Systematic Review.
Travis Dias, Benjamin G Lerch, Jonathan S Slowik and 4 others
PMID 37795321WHAT IT FOUND
Interval throwing programs raised elbow stress as distance and effort increased, but the distance where long toss matched full-effort pitching stress varied.
Partial-effort mound throws stayed below full-effort pitching stress, and mechanics were not identical.
Key findings
01Most included studies found elbow varus torque rose as flat-ground throwing distance increased, while some reported different trends.
02In partial-effort mound pitching, elbow varus torque increased with effort, but all partial-effort pitches produced less torque than full-effort pitching.
03Flat-ground throwing kinematics differed from full-effort pitching, with shorter stride, lower foot position at foot contact, and more upright trunk, while shoulder external rotation and arm speed increased with distance.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The search may have missed relevant articles. Two included studies were conference abstracts. The included studies measured different biomechanical variables. Six studies used optical motion capture and seven used an inertial measurement unit sensor, and the raw numbers from the two technologies cannot be combined. Some included studies had small participant groups; five studies had fewer than 20 subjects. Only one study reported partial-effort pitching kinematics, and it was published more than 25 years ago. Most participants were high school or college pitchers, so the review says little about youth or professional pitchers. Flat-ground throwing instructions varied, including whether a crow hop was used and how hard or on what line the throw was made. The review did not evaluate injury outcomes, pain, return to sport, or program efficacy. The authors did not evaluate the optimal progression of the interval throwing program.
Declared interests
The authors reported no conflicts of interest.
The easy way to misread this
Do not conclude that interval throwing fully reproduces full-effort pitching loads or mechanics. The review found that partial-effort mound throws produced less elbow varus torque than full-effort pitching, and flat-ground throws did not consistently reach full-effort pitching torque at a predictable distance.