Every pitcher who’s gone through a throwing progression has heard it: “Keep it at 75% effort.” It’s the language of restraint—a cue meant to protect the arm, preserve tissue recovery, and build back up safely. But what if 75% effort doesn’t actually mean 75% of the stress?

A 2023 motion capture analysis revealed that even when pitchers consciously dialed back to 50–75% of their perceived maximum, their elbows still absorbed between 74–81% of the torque seen at full intensity. That discovery has quietly rewritten one of the most common assumptions in return-to-throwing and workload management: that throwing softer proportionally unloads the arm.

[The Primary Problem]

Across professional baseball, return-to-throwing programs are built around a simple equation—less intent equals less stress. But this logic assumes that subjective effort scales linearly with joint torque. That belief drives everything from early rehab throwing to pitch count prescriptions.

The flaw is that “effort” is a psychological variable. Torque is a mechanical one. They don’t always move together.

When a pitcher throws at 75% effort, the intent to slow down is filtered through deeply ingrained motor patterns built for maximum velocity. The arm may slow slightly, but kinetic chain sequencing, timing, and elastic energy transfer often remain close to full-effort patterns. The result is a delivery that feels easier but loads similarly.

That’s what the 2023 motion capture study set out to test: whether dialing back effort produces a meaningful mechanical unload—or just the illusion of one.

[Major Findings]

The study’s findings were striking. When pitchers threw at what they perceived as 75% effort, elbow torque remained at 81% of their full-effort maximum. Velocity only fell to 90%.

At 50% effort, torque decreased slightly more—to 74% of max—but velocity still hovered around 85%. For every 25% decrease in perceived effort, elbow stress dropped just 13%, while velocity declined only 7.5%.

That relationship revealed two key points.

First, throwing effort and joint load are not 1:1 variables. A pitcher’s perception of effort is not a reliable gauge of internal stress. Second, velocity—often used as a proxy for load—also fails to tell the full story. Even when the radar gun shows lower numbers, the elbow may still be enduring substantial varus torque.

Perhaps most important, the study found that mechanical variability increased as effort decreased. At 50% intensity, motion patterns became less repeatable [intraclass correlation coefficients ≥ 0.93 for torque, ≥ 0.80 for velocity at full effort, but significantly lower at reduced effort]. In practical terms, pitchers lost consistency when trying to “take it easy.”

This introduces a paradox: the very throws meant to protect the arm may actually introduce instability, altering kinematics in ways that reduce mechanical efficiency.

[Why This Matters for Baseball Performance Training]

For coaches and rehab specialists, these results carry enormous implications.

If torque reduction doesn’t scale with perceived effort, then our current models for gradual throwing progression—built on subjective cues like “75% effort” or “light catch”—are flawed.

A pitcher’s intent to throw easier doesn’t automatically translate to safer mechanical output. The nervous system’s ingrained sequencing drives near-maximal force transmission through the chain, even when the athlete believes he’s easing off.

That means that a pitcher returning from a UCL reconstruction, or one managing chronic medial elbow soreness, might be exposing their tissues to nearly the same mechanical load they’re trying to avoid.

The secondary finding—reduced mechanical repeatability at lower effort—compounds the issue. When variability increases, the likelihood of inefficient kinetic transfer and compensatory movement rises. Instead of reinforcing stable mechanics, “easy throws” may destabilize them.

From a performance perspective, this challenges one of baseball’s most deeply rooted rituals: the sub-maximal catch play session. The assumption that it offers both mechanical recovery and skill retention may be oversimplified.

[How We Apply This at Velo University]

At VeloU, we’ve learned that effort perception is a poor metric for load management. Instead, we focus on objective feedback through measurable data: torque sensors, grip force metrics, radar readings, and arm slot tracking.

When athletes are reintroduced to throwing post-rest or post-injury, the goal isn’t simply to “throw easier”—it’s to throw more efficiently. That means emphasizing patterns that maintain timing, posture, and segmental sequencing even at reduced output levels.

In practical terms, we apply this research by:

• Monitoring torque instead of relying solely on intent cues.
  
  A radar gun can’t tell us what the elbow feels; a torque sensor can.
  
  
• Prioritizing movement integrity at submaximal efforts.
  
  If variability increases at 50%, we target drills that reinforce repeatability—constraint throws, mirror work, and tempo-controlled reps rather than pure “light toss.”
  
  
• Reframing progression language.
  
  Instead of saying “throw 75%,” we cue “throw with the same movement pattern but lower output.” That distinction preserves the kinetic structure while allowing controlled intensity modulation.
  
  

Ultimately, this study reinforces the principle that mechanical efficiency—not perceived effort—is the key to both durability and velocity retention.

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The data reveal a hard truth: “partial effort” doesn’t equal “partial load.” The elbow remains under substantial torque even when velocity drops. More importantly, the throws designed to protect may inadvertently degrade motor consistency.

That doesn’t mean submaximal work should be eliminated—it remains an essential part of tissue reconditioning and throwing progression. But it does mean that subjective effort alone cannot guide workload safely.

The next evolution in baseball performance isn’t about throwing harder or softer—it’s about throwing with feedback. Only through quantifiable monitoring can we truly manage recovery, progression, and long-term arm health.

As the 2023 study shows, effort perception is an unreliable compass. Objective data must now take its place.

Reference:

Fiegen, A. P., Nezlek, S. P., Loushin, S. R., Christoffer, D., Verhoeven, M., Kaufman, K. R., & Camp, C. L. (2023). The effect of reduced-effort pitching on elbow torque and ball velocity in high school pitchers. The American Journal of Sports Medicine, 51(3), 677–684. https://doi.org/10.1177/03635465221144020