Long-Toss Throwing from 120 Feet and Mound Throwing Place Similar Varus Torque on the Elbow

Leafblad ND, Larson DR, Fleisig GS, et al. Variability in baseball throwing metrics during a structured long-toss program: Does one size fit all or should programs be individualized? Sports Health A Multidiscip Approach. 2019;11(6):535-542. doi:10.1177/1941738119869945

Background

Long-toss throwing is considered an integral component of structured rehabilitation interval throwing programs.  During long-toss throwing, there is great variability in elbow varus torque, rotational velocity, and arm slot position across different baseball pitchers.  Given this variability, well-structured interval throwing programs should be individualized to the athlete.  Understanding how long-toss throwing influences different metrics would be useful for the rehabilitation specialists who prescribe and monitor interval throwing programs for pitchers.

Purpose

The purpose of this study was to:

  1. Describe the progression of throwing metrics (arm speed, rotation, torque, velocity, etc) through a structured long-toss program,
  2. Quantify the intra-thrower reliability at each stage of throwing,
  3. Assess inter-thrower reliability between pitchers.

Study Population

  • High school and collegiate baseball pitchers (n = 60)
  • Free from any throwing restriction or injury
  • The primary position was as a pitcher

Methods

  • 5 throws from each of the following: long-toss at 90, 120, 150, and 180 ft, followed by maximal effort fastballs from a standard pitcher’s mound.
  • Participants asked to throw “on a line” without crow- hops or bouncing the ball.
  • Players wore a Motus baseball sleeve with an inertial measurement unit to track arm slot, arm velocity, maximum shoulder external rotation, and elbow varus torque.
  • Ball velocity was tracked with a radar gun
  • Intra- and inter-thrower reliabilities were calculated for each metric at every stage of throwing.

Key Results

Leadblad Image

  • Ball Velocity
    • Ball velocity increased significantly at each progressive distance and from the mound.
  • Elbow Varus Torque
    • There was a significant difference in elbow varus torque between long-toss at 90 ft and all other distances (P < 0.05).
    • No significant difference in elbow varus torque at 120 ft, 150 ft, 180 ft, and mound throwing.
    • Pitching from the mound did not place more torque on the elbow than long-toss throwing from 120 ft and beyond.
  • Intra-thrower reliability
    • Determined to be excellent (ICC >0.75) throughout the throwing program.
  • Inter-Thrower Reliability
    • Arm slot demonstrated the worst inter-thrower reliability (coefficient of variation [CV] > 5% at all distances).
    • The mean CV was <5% for arm speed, shoulder rotation, elbow torque and ball velocity for each throwing distance.

Final Thoughts & Practical Applications

A key finding from this study was throwing from the mound placed similar varus torque on the elbow to long-toss throwing from 120 ft to 180 ft.   This suggests mound throwing may be introduced in some pitchers once he or she has progressed to 120 ft within their interval throwing program.

Intra-thrower reliability data was superior to inter-thrower reliability for most metrics.  This favors an individualized approach to interval throwing program prescription and progression.  As the authors suggest, “there is no one-size-fits-all approach.”

Maximum-effort throwing from the mound placed similar varus torque on the elbow to 180 ft long-toss throwing (71.1 compared with 71.2 N·m).  This occurred despite ball velocity and arm speed being highest throwing from the mound.  Overall, ball velocity and elbow torque did not correlate with one another.  Therefore, methods other than those utilizing a radar gun should be used to track torque on the elbow during long-toss throwing.  Inertial measurement units such as those used in this study are becoming widely used and show some promise.

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