Velocity has long been the great separator in baseball. Yet for decades, the conversation around where velocity truly comes from has leaned heavily toward arm strength, stride length, and hip-shoulder separation. What Wang et al. [2025] reveal is that we may have been looking at the wrong things, or at least not looking closely enough. The pelvis, acting as the bridge between the lower body and trunk, emerges not just as a passive structure but as the most powerful regulator of velocity. More specifically, it is the control of pelvic motion in the transverse plane — and the way the pelvis coordinates with the trunk — that distinguishes high-velocity pitchers from their peers.

The Primary Problem

For years, coaches and scientists alike have wrestled with the question: why do two athletes with similar strength, mobility, and intent throw at vastly different speeds? Traditional explanations often emphasized arm path mechanics or lower-body force output. While both matter, they fail to explain the efficiency differences between pitchers who appear equally “strong” or “mobile.” This is where pelvic control enters the discussion. The pelvis dictates timing, organizes sequencing, and either facilitates or disrupts the energy transfer from the legs to the trunk to the arm. Without pelvic stability and precise coordination, the chain breaks down — no matter how strong the athlete may be.

Major Finding from Wang et al. [2025]

The study’s most provocative finding is that pelvic rotation variability in the transverse plane was the single strongest predictor of velocity (r = –0.78). In other words, pitchers who displayed less inconsistency in how their pelvis rotated during the delivery threw harder. This isn’t just about “turning the hips faster.” It’s about the pelvis acting like a gyroscope — stable enough to transfer energy, but dynamic enough to coordinate with the trunk at exactly the right moments.

The research also revealed the value of simple clinical tests. A single-leg balance test, when viewed through the lens of transverse pelvic control, strongly predicted velocity on both the stride leg (r = –0.76) and drive leg (r = –0.65). This gives coaches and clinicians a low-cost, high-value screening tool that could help identify which pitchers are leaving velocity untapped because of poor rotational stability.

Even more fascinating is how the pelvis and trunk coordinate across the pitching cycle. From foot contact to maximal external rotation, the ability to create dissociation — pelvis and trunk moving out of phase — correlated positively with velocity (r = 0.74). From maximal external rotation to maximal internal rotation, however, high-velocity pitchers displayed in-phase coordination, with pelvis and trunk rotating together (r = 0.58). This shifting relationship highlights that pitching is not just about separation; it’s about knowing when to separate and when to sync.

Why This Matters for Baseball Performance

This finding forces us to expand how we define “mechanics.” Too often, we isolate hip-shoulder separation as the gold standard. But what this study makes clear is that separation is only valuable if preceded and followed by the correct pelvic control patterns. Poor stability early disrupts dissociation; poor coordination later reduces the ability to deliver force efficiently.

It also clarifies why two pitchers with nearly identical strength profiles can produce vastly different velocities. One has refined pelvic-trunk timing; the other does not. This distinction shifts training from being purely about adding horsepower to focusing on how that horsepower is harnessed and released.

How We Apply This at VeloU

At VeloU, this research validates what we’ve seen anecdotally: pitchers who struggle with velocity often lack rotational stability and control, not raw strength. In practice, this means:

• Single-leg balance under rotational challenge. Standing on the stride or drive leg with resistance bands creating transverse pull, forcing the pelvis to stabilize dynamically.
  
  
• Resisted trunk-pelvis dissociation drills. Athletes stabilize the pelvis while rotating the trunk against banded or manual resistance, mirroring the early cocking phase.
  
  
• Isometric rotational holds. Pelvis fixed against resistance while the trunk attempts to rotate, reinforcing stability under load.
  
  
• Sequencing drills. Teaching dissociation early in the delivery, then coordinated “catch-up” later, so athletes experience the exact timing demands of high-velocity pitching.
  
  

We are also cautious to note that sagittal control — although not predictive of velocity in this study — cannot be ignored for overall movement health. Likewise, the lack of frontal plane assessment is a gap that future studies must address. Pelvic hike, lateral lean, and frontal instability remain strong candidates for influencing both velocity and injury risk.

The Wang et al. [2025] study is a watershed moment in understanding pitching performance. It shows us that velocity is less about sheer output and more about precision — the pelvis acting as both stabilizer and conductor of movement. Yet, we must be cautious not to over-interpret. The absence of frontal plane analysis means the picture is incomplete, and we cannot yet claim pelvic control is the key, only that it is a key. Still, this research pushes the field forward by giving coaches tangible metrics and screenable qualities that can be addressed in training.

At VeloU, the implications are clear: we will continue to prioritize not just strength and mobility but the precise coordination of the pelvis and trunk. The pitchers who master this subtle skill will not just throw harder — they will do so more efficiently, with a reduced likelihood of breaking down.

References

Wang, X., et al. (2025). Pelvic Control and Pelvic-Trunk Coordination as Key Determinants of Pitching Velocity in Baseball Pitchers. [Journal name, volume, pages].

(If you’d like, I can expand this with references from your indexed library to reinforce training parallels — e.g., studies on hip mobility, trunk kinematics, or pelvic tilt in pitchers.)