Elbow Flexion Excursion: Why High School Pitchers Move More, Stress More, and Gain Less

Introduction

Every pitching coach has seen it: the younger pitcher whose arm seems to “move too much.” The elbow flexes deeply at hand break, stays bent through acceleration, and never quite straightens at release. The delivery looks loose—sometimes even athletic—but beneath that motion may lie a mechanical inefficiency that compounds over time.

A 2025 study published in The American Journal of Sports Medicine by Manzi and colleagues quantified this phenomenon through a motion capture analysis of 59 high school (HS) and 288 professional (PRO) pitchers. Their goal was to evaluate how elbow flexion excursion—the total degree of flexion and extension the elbow travels through during the pitching motion—relates to both ball velocity and elbow stress.

The findings suggest that more motion is not always better. In fact, for younger pitchers, excessive elbow excursion may reflect deeper inefficiencies in how force is transferred up the kinetic chain—and may offer little payoff in velocity for a much higher cost in joint stress.

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The Primary Question

The researchers wanted to understand two key relationships:

1. Does greater elbow flexion excursion increase throwing velocity?
   
   

2. How does that increased motion affect the loads experienced by the elbow joint, particularly elbow varus torque (EVT) and medial elbow force?
   
   

These questions carry major implications for athlete development. For years, coaches have emphasized “layback” and “arm whip” as hallmarks of efficient velocity generation. But those concepts often get conflated with excessive elbow motion, especially in younger pitchers who haven’t yet developed the trunk control or timing precision to coordinate their segments efficiently.

If elbow flexion and extension become exaggerated or poorly timed, they may simply magnify distal stress rather than translate to usable power.

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What the Study Found

High school pitchers moved through more range of motion.

HS pitchers demonstrated an average elbow flexion excursion of 70°, compared to 63° in professionals (P < .001). The difference may seem small, but it reflects a meaningful change in how the arm organizes through the throw.

The starting position matters.

HS pitchers began their motion with the elbow already more flexed at foot contact—about 8° greater flexion than professionals. That earlier bend persisted throughout the delivery, meaning the entire kinetic sequence started “shorter” and stayed more compact.

Professionals released the ball from a more extended position.

Despite less total motion, professional pitchers achieved greater extension at release. Their elbows didn’t travel as far through flexion, but they ended up with more leverage and less stress. This represents a form of mechanical efficiency: a smaller range producing the same—or better—result.

Stress rose sharply in high school arms.

For every 1 SD increase in elbow excursion:

• EVT rose 0.34–0.40 SD in HS pitchers, versus only 0.13–0.22 SD in professionals.
  
  

• Medial force increased 1.9–2.3% of body weight in HS pitchers versus 1.4–1.7% in professionals.
  
  

This means that in high school pitchers, each additional increment of elbow movement produced a disproportionate rise in torque and tensile force. The arm was doing more work to achieve less velocity.

Velocity gains were minimal.

High school pitchers gained roughly +2 mph for every standard deviation increase in excursion, while professionals gained less than +1 mph. Those modest returns suggest that the extra motion does not translate into meaningful on-field advantage.

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Why This Matters

The difference between professional and high school mechanics likely reflects proximal control. Professional pitchers appear to generate their velocity upstream—through efficient sequencing of the pelvis, trunk, and scapular complex—allowing the elbow to move through a tighter, more constrained arc.

High school pitchers, by contrast, often rely on the arm to “finish” the motion. They start with more flexion at foot contact, fail to fully extend at release, and remain flexed into the deceleration phase. This sustained flexion after ball release—a pattern observed frequently in the study—is associated with increased valgus stress and potential injury risk.

The researchers concluded that reduced elbow excursion in professionals may serve as a protective adaptation rather than a limitation. Their arms are not simply stiffer; they are more stable within a refined movement window.

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Reframing the Coaching Lens

This study invites a rethinking of how we coach youth pitchers. Too often, range of motion is viewed as inherently positive—a sign of looseness or athleticism. But the question isn’t how much the arm moves; it’s how well that movement fits into the broader kinetic sequence.

If the trunk rotates too early, or the pelvis decelerates too late, the elbow may be forced to compensate by flexing more or staying flexed longer. The arm becomes the fail-safe for a system that’s out of sync.

At Velo University, we interpret these findings as evidence that arm motion is a mirror of body control. The elbow’s path reflects what the lower half and trunk are—or aren’t—doing. Addressing timing, stability, and center-of-mass control upstream is likely the real solution to excessive elbow excursion, not direct constraint of arm path.

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How Velo University Applies This

When analyzing elbow kinetics during high-speed motion capture, we look at both range and rate. A high total excursion paired with elevated torque indicates compensatory sequencing, not simply mobility.

Our training interventions prioritize:

• Pelvic-trunk timing: drills that synchronize rotation and tilt to reduce distal overwork.
  
  

• Eccentric control in the flexor-pronator complex: ensuring the elbow can resist valgus load as force transfers distally.
  
  

• Proximal stability and deceleration control: improving scapular and trunk deceleration to avoid sustained elbow flexion post-release.
  
  

These systems-based corrections consistently yield reductions in elbow torque without any loss of velocity—a pattern that mirrors what this study observed in professional pitchers.

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The Bigger Picture

Mechanics don’t exist in isolation. The arm’s kinematics are simply the visible outcome of the body’s deeper coordination strategies. What this study reminds us is that youth pitchers are not just smaller versions of professionals. Their patterns represent developing systems that rely more heavily on the arm to create speed, often at the expense of efficiency.

By identifying excessive elbow excursion as a stress amplifier with limited velocity benefit, coaches and performance specialists gain a measurable marker for early intervention.

The most efficient arms in baseball aren’t those that move the most—they’re the ones that move just enough.

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Reference

Manzi, J. E., Dowling, B., Estrada, J., Sudah, S. Y., Moran, J., McElheny, K. D., Erickson, B. J., Ruzbarsky, J., Ciccotti, M. C., Ciccotti, M. G., & Dines, J. S. (2025). Elbow flexion excursion: Intra- and inter-throwing arm kinetic evaluations in high school and professional baseball pitchers. The American Journal of Sports Medicine, 53(7), 1731–1738. https://doi.org/10.1177/03635465251338080