Pitching is often framed as a series of explosive, anaerobic efforts — and that’s true. But what happens between pitches, and over the course of an entire outing, is also influenced by aerobic fitness. A recent study of Major League pitchers examined how VO₂max and anaerobic threshold relate to performance. The findings show a clear divide between starters and relievers: for starters, aerobic fitness strongly predicted pitching success. For relievers, it didn’t.

What the Study Found
Researchers collected VO₂max and anaerobic threshold data from 24 Major League pitchers over seven seasons (2007–2013). Testing used a modified Bruce treadmill protocol with the CardioCoach™ CO₂ metabolic analyzer. Pitching performance was tracked across full seasons using advanced stats (ERA, WHIP, FIP, K/9, BB/9, HR/9, Wins).

Key results:

• Starters vs. Relievers: Starters had significantly higher VO₂max (49.5 vs. 45.3 mL·kg⁻¹·min⁻¹). No role-based difference in anaerobic threshold.
  
  
• Performance for Starters: Higher VO₂max correlated with lower ERA (r = –0.678), WHIP (r = –0.685), and FIP (r = –0.567). VO₂max also predicted higher strikeouts (r = 0.572), better K/9 (r = 0.614), and more wins (r = 0.548).
  
  
• Above vs. Below Average VO₂max: Starters with above-average VO₂max had a 1.3 run lower ERA (3.77 vs. 5.04) and better WHIP (1.25 vs. 1.48).
  
  
• Anaerobic Threshold (AT): AT showed modest correlations with ERA and WHIP in starters.
  
  
• Relievers: No consistent performance benefits from higher VO₂max — in fact, those with higher aerobic fitness sometimes pitched worse (higher FIP).
  
  

Why This Matters
These findings highlight a role-specific truth: starting pitchers depend more heavily on aerobic fitness to sustain performance over longer outings. Relievers, by contrast, may not require the same aerobic adaptations since their workloads are shorter and more power-focused.

This study also shifts the conversation beyond simply maintaining velocity. By linking aerobic fitness directly to game stats like ERA, WHIP, and strikeouts, it demonstrates that VO₂max has measurable value at the highest level of play.

How We Apply This at VeloU
For starters, VO₂max is not just a lab metric — it’s a predictor of consistency and resilience on the mound. But the way it’s trained matters.

• The Aerobic Foundation: VO₂max is primarily an aerobic adaptation, driven by cardiovascular and mitochondrial efficiency. Training in the 70–85% HRmax range (Zones 2–3) builds stroke volume, capillary density, and mitochondrial function — the physiological foundation that supports endurance. This is what raises the “ceiling” for how much oxygen the body can deliver and use.
  
  
• The Anaerobic Layer: Developing VO₂max for sport performance requires more than steady-state work. Intervals at or above 90–100% VO₂max (for example, 3–5 minutes at high intensity with short rest or repeated sprints) stress both aerobic delivery and anaerobic buffering. This builds lactate tolerance and sharpens the ability to sustain intensity near that ceiling.
  
  
• The Balance: For baseball, this means starters should integrate both approaches — using aerobic work to build the base, and layering anaerobic exposures to apply it under the metabolic stress of competition. The goal isn’t just to survive at ~85% HRmax, but to make it harder to even reach that level during games.
  
  
• Role-Specific Training: Relievers, on the other hand, may not benefit from aerobic emphasis. Their conditioning should lean toward explosive power and rapid recovery, while still maintaining enough aerobic capacity to support back-to-back outings.
  
  

This study shows that VO₂max is more than a physiological curiosity — for starting pitchers, it directly correlates with performance. Developing aerobic fitness through balanced conditioning can help starters maintain command, delay fatigue, and perform deeper into games. For relievers, the demands are different, and so the training must be as well. At VeloU, we believe VO₂max testing and individualized conditioning are key tools to ensure pitchers are not just strong, but also built for the specific demands of their role.

Reference
Gillett, J. S., Dawes, J. J., Spaniol, F. J., Rhea, M. R., Rogowski, J. P., Magrini, M. A., Simao, R., & Bunker, D. J. (2016). A description and comparison of cardiorespiratory fitness measures in relation to pitching performance among professional baseball pitchers. Sports, 4(1), 14. https://doi.org/10.3390/sports4010014