In performance training, the relationship between effort, fatigue, and adaptation is often misunderstood. Many athletes still believe that grinding through sets to failure guarantees progress. Yet new evidence suggests that fatigue management—rather than fatigue accumulation—may be the key to unlocking performance gains. A 2023 systematic review and meta-analysis published in Sports Medicine by Jukic et al. examined how different “velocity loss thresholds” (the drop in bar speed within a set) affect adaptations in strength, hypertrophy, and power.

Across 37 studies and more than 700 participants, researchers found that while pushing sets deeper into fatigue increased muscle size, it did not improve strength or power—and often compromised them. The implications are especially relevant for baseball athletes, where performance depends on speed, precision, and the ability to recover rapidly between high-intensity bouts.

What the Study Found

Velocity loss (VL) refers to how much bar speed declines from the first rep to the last rep in a set. Coaches can use VL as a real-time indicator of fatigue. The review found a clear pattern:

1. As VL increases, fatigue rises linearly. Blood lactate and perceived exertion escalated, while countermovement jump and sprint performance declined.
   
   
2. Strength gains plateau regardless of VL. Whether sets ended at 10% or 40% velocity loss, overall strength improvements were statistically equivalent.
   
   
3. Hypertrophy increases with higher VL. Every 10% increase in VL was linked to greater muscle growth (β = 0.006; 95% CI 0.001–0.012).
   
   
4. Power and speed suffer under high fatigue. Jump height, sprint velocity, and bar speed all declined at higher VL thresholds (CMJ β = –0.040; Sprint β = 0.001).
   
   
5. Low to moderate VL (10–25%) is optimal. These ranges provided the best balance between muscular adaptation, neuromuscular quality, and recovery.
   
   

In short, higher fatigue yields bigger muscles but slower movements—a poor tradeoff for a baseball athlete who relies on quick-twitch efficiency and rotational explosiveness.

Why This Matters for Baseball Athletes

Baseball performance is defined by repeated, high-velocity efforts: swinging, throwing, sprinting. The body’s ability to produce force quickly, not just maximally, determines success. This study confirms that pushing training sets to failure—high VL—is not only unnecessary for strength gains but potentially detrimental to sport-specific performance.

For a pitcher or hitter, preserving bar speed during resistance training mirrors the neuromuscular demands of the game. Low to moderate VL ensures that each rep reinforces high-quality movement patterns and motor control under fatigue, translating to greater transfer in skill execution. Conversely, chronic exposure to high VL may blunt fast-twitch fiber expression and prolong recovery—factors that can compromise in-season readiness and increase cumulative fatigue risk.

How Velo University Applies This

At VeloU, we view fatigue as a variable—not a badge of honor. Our resistance training protocols integrate velocity-based monitoring to ensure that bar speed, not arbitrary repetition counts, dictates set termination. In the off-season, moderate VL exposure is used strategically to promote hypertrophy where structural development is needed—particularly in the lower half and posterior chain.

During the season, however, training pivots toward maintaining performance readiness. We prioritize low VL thresholds (10–15%), emphasizing rapid intent and precise execution. This ensures that every repetition enhances neural drive and bar velocity—qualities that directly translate to mound efficiency, bat speed, and throwing velocity.

By tailoring VL thresholds to the phase of training, we can target adaptation without compromising readiness, providing a measurable method for balancing performance gain and fatigue cost.

Closing Thoughts

This meta-analysis challenges the long-held notion that more fatigue equals more progress. In reality, the optimal dose depends on context: high fatigue builds size, but low fatigue builds speed. For baseball athletes, the ability to repeatedly express power is far more valuable than the ability to repeatedly express effort.

Velocity-based training provides a way to quantify that difference. By understanding how fatigue shapes adaptation, coaches can prescribe with precision—ensuring athletes not only grow stronger but also stay faster, fresher, and more explosive across the season.

References:

Jukic, I., Pérez-Castilla, A., García-Ramos, A., Van Hooren, B., McGuigan, M. R., & Helms, E. R. (2023). The acute and chronic effects of implementing velocity loss thresholds during resistance training: A systematic review, meta-analysis, and critical evaluation of the literature. Sports Medicine, 53(2), 177–214. https://doi.org/10.1007/s40279-022-01754-4