There's a ritual that happens in every dugout between innings. A pitcher walks off the mound, sits down, throws a jacket over his shoulder, and waits. The jacket is supposed to keep the arm warm. The logic is simple, if you let the arm cool down, it'll stiffen up, and you'll lose feel, velocity, command. So you keep it warm. You keep the blood flowing. You stay ready. And for decades, that's been the standard. Except a 2016 study published in the Journal of Strength and Conditioning tested whether that standard actually makes sense. Eight NCAA pitchers threw a simulated five-inning start. Between innings, half of them used intermittent cooling, four minutes of ice applied to the deltoid and forearm. The other half followed the traditional approach, passive rest, no cooling, just sitting. The results were striking. The pitchers who cooled their arms threw harder on average. They lost less velocity in the later innings. They reported lower perceived exertion and better recovery between innings. And anecdotally, they preferred the cooling, even though it contradicted everything they'd been taught about keeping the arm warm.

The average velocity difference was modest, about 0.6 meters per second, roughly 1.3 miles per hour. But the effect was more pronounced in the later innings. By inning four, the cooling group was throwing 31.3 meters per second while the no-cooling group had dropped to 30.0, a difference of 1.3 meters per second, nearly 3 miles per hour. By inning five, the gap was still there. The cooling group maintained 31.3 meters per second. The no-cooling group climbed back slightly to 30.4, but the cooling group was still faster. Perceived exertion, measured by rating of perceived effort, was 35 percent lower in the cooling group. Perceived recovery, measured by a standardized scale, was significantly higher in the cooling group between innings. The pitchers who iced between frames felt fresher, threw harder, and maintained velocity deeper into the game. All from four minutes of cold.

When The Body Overheats, The Brain Breaks Down First

To be honest, this reminds me of watching pitchers struggle in late-summer games when the temperature climbs above 90 degrees. Velocity starts dropping. Command gets loose. Fastballs start leaking over the plate. The assumption is always that the arm is tired, that the muscles are fatigued, that the shoulder or elbow can't keep up. But research on environmental heat suggests the problem might start in the brain, not the arm. A 2021 study on professional baseball games analyzed 480 contests across different temperature ranges. In games played above 93 degrees Fahrenheit, offensive production spiked. Slugging percentage jumped to 0.467. Home runs per nine innings rose to 1.24. WHIP increased from 1.48 in cold conditions to 1.60 in extremely hot games. Pitchers threw fewer strikes. Command deteriorated. And strikeout rates didn't change, suggesting the issue wasn't overall control but zone location, the ability to execute specific pitches to specific spots.

The researchers attributed the decline to hyperthermia-induced cognitive decline. Core temperatures above 38.5 degrees Celsius, roughly 101 degrees Fahrenheit, impair working memory and executive function, both of which are critical for pitch strategy and motor execution. The pitcher's body isn't necessarily failing. His brain is. And when the brain struggles to process information, make decisions, and coordinate complex movements under fatigue, the arm compensates. Command suffers. Velocity drops. Pitches flatten. Hitters feast. The researchers noted that hitters, who spend most of the game resting in the dugout, experience less physiological strain than pitchers, who are working continuously. The disparity creates an uneven playing field when temperatures climb. The pitcher is fighting his own body's thermoregulatory response while the hitter is comfortable.

The cooling study didn't track core temperature or cognitive function directly, but the mechanism is plausible. Applying ice to the deltoid and forearm reduces local tissue temperature and peripheral blood temperature. That cooler blood circulates back to the core, lowering overall body temperature and potentially reducing the thermal stress that impairs cognitive and motor function. The four minutes of cooling between innings might not seem like much, but if it's enough to blunt the rise in core temperature, it could preserve the brain's ability to execute under fatigue. And if the brain stays sharp, the arm stays sharp. The velocity data support that. The pitchers who cooled maintained their fastball speed in innings four and five. The pitchers who didn't cool showed measurable decline.

Less Time Between Innings, Better Recovery?

One of the most counterintuitive findings in recent baseball research comes from data on the pitch clock. A 2025 study comparing MLB pitchers before and after the implementation of the pitch clock found that pitchers under the clock threw 61 percent more pitches per season before UCL injury than pitchers in the pre-clock era. The incidence of UCL tears didn't change, but the workload tolerance did. Pitchers were handling more stress before breaking down. The researchers speculated that reducing the time between pitches, and by extension reducing the total game time, might improve fatigue management. Less time under tension. Less opportunity for central and peripheral fatigue to accumulate. Games have been reduced by an average of 30 minutes since the pitch clock's introduction. That's 30 fewer minutes of sitting, waiting, cooling down passively, and then trying to ramp back up.

The cooling study suggests a different approach to managing between-inning recovery. Instead of keeping the arm warm and waiting passively, what if you actively intervene? Four minutes of cooling reduced perceived exertion and improved perceived recovery. The pitchers felt better. They reported less fatigue. And they maintained velocity. The traditional approach, keeping the arm warm, assumes that passive warmth is protective. But passive warmth might not be doing anything. It's not actively managing fatigue. It's not addressing tissue temperature. It's not modulating the inflammatory or thermoregulatory responses that drive performance decline. It's just, well, passive. The cooling intervention, by contrast, is active. It's targeting a mechanism, local and systemic cooling, that plausibly affects performance.

There's also the question of what's happening to the arm between innings when you don't cool. Muscle temperature rises during activity. Blood flow increases to dissipate heat. Metabolic byproducts accumulate. Inflammatory markers spike locally. If you do nothing between innings, those processes continue. The tissue stays warm. The metabolites linger. The inflammation persists. By the fourth or fifth inning, the cumulative effect might be enough to degrade neural drive, reduce force output, and impair coordination. The cooling group in this study interrupted that process. Four minutes of ice reduced local tissue temperature, constricted blood vessels temporarily, and potentially cleared some of the metabolic waste that accumulates during high-intensity activity. When the pitchers returned to the mound, their arms were in a better state to perform.

The Perception Problem Matters As Much As The Performance Problem

One of the most interesting findings in the cooling study wasn't velocity. It was perceived exertion. The cooling group reported 35 percent lower RPE, rate of perceived effort, than the no-cooling group. That's not a small difference. That's the gap between feeling like you're grinding through every pitch and feeling like you still have something left. Perceived effort is subjective, but it's not meaningless. Athletes who feel more fatigued perform worse, not just because their bodies are tired, but because their brains interpret the fatigue signal and adjust output accordingly. If you feel like you're working harder, you might back off subconsciously. You might lose intent. You might alter mechanics to conserve energy. The cooling group felt less fatigued. And feeling less fatigued, they maintained velocity.

There's also evidence from other research that reducing perceived exertion improves performance. A 2025 study on caffeine and Rhodiola rosea supplementation in volleyball athletes found that the combined group, which showed the greatest improvements in explosive power and fatigue resistance, also reported the lowest perceived exertion by week four. The athletes who felt less tired performed better. The mechanism isn't purely physical. It's perceptual. The brain gates effort based on how hard it thinks the body is working. If cooling between innings reduces the perception of fatigue, even if the actual physiological fatigue is similar, the brain might allow higher output. The pitchers in the cooling group threw harder not just because their arms were fresher, but because they felt fresher.

The perceived recovery scale reinforced this. Between innings, the cooling group reported significantly better recovery than the no-cooling group. They felt more ready to go back out. They felt more prepared to execute. And that subjective readiness translated into objective performance, maintained velocity, lower RPE, better execution in late innings. For a starting pitcher, the difference between feeling ready and feeling drained in inning five is the difference between finishing strong and getting pulled early. The cooling intervention didn't just preserve velocity. It preserved confidence. And confidence, especially under fatigue, is a performance variable that doesn't show up in biomechanics data but absolutely shows up in results.

The Practical Side Nobody's Talking About

The study used a specific cooling protocol. Four minutes of ice applied to the deltoid and forearm between innings. The ice was wrapped and secured, not loose or haphazardly placed. The pitchers then performed a structured warm-up routine before returning to the mound. That last part is critical. The study didn't just ice the arm and send them back out. The athletes re-warmed appropriately. They went through their normal bullpen routine. They activated the muscles, restored range of motion, and prepared to throw at full effort. The cooling wasn't a replacement for warm-up. It was an addition to the between-inning routine that seemed to enhance recovery without compromising readiness.

For coaches or pitchers considering this approach, the protocol matters. You can't just slap ice on the shoulder for 30 seconds and expect results. Four minutes is specific. The application sites, deltoid and forearm, are specific. And the warm-up afterward is non-negotiable. If you cool the tissue but don't re-activate it, you're asking for stiffness, reduced neural drive, and potentially worse performance. The cooling group in this study maintained velocity because they cooled strategically and warmed up properly. The no-cooling group declined because they did nothing to manage the cumulative fatigue. But a poorly executed cooling protocol, too much ice, too long, inadequate warm-up, could create problems that passive rest doesn't.

There's also the question of environmental context. This study was conducted in temperate conditions. The athletes weren't pitching in 95-degree heat with high humidity. They were in a controlled lab setting simulating a game. Would cooling between innings produce even greater benefits in hot weather, when core temperature rises faster and cognitive decline sets in earlier? Probably. The environmental heat study showed that pitchers struggle more as temperatures climb. Cooling might be even more effective under those conditions, not just for maintaining velocity but for preserving decision-making, command, and the cognitive functions that break down when the body overheats. But we don't have data on that yet. The cooling study was small, eight pitchers, and limited to one environmental condition. Generalizability is uncertain.

What This Means For Pitchers Who Want To Finish Games

If you're a starting pitcher, especially one who struggles to maintain velocity in late innings, this study suggests a tool worth considering. Four minutes of strategic cooling between innings, applied to the deltoid and forearm, might preserve fastball speed, reduce perceived fatigue, and improve how recovered you feel before going back out. The gains aren't massive, 1.3 to 1.5 miles per hour in later innings, but they're consistent. And in a sport where the difference between a quality start and getting pulled in the fifth is often a couple of pitches, a couple of miles per hour, or a couple of well-located fastballs, those marginal gains matter.

The key is execution. You need a structured protocol. Four minutes of ice, properly applied, with a deliberate warm-up routine afterward. You can't just ice randomly and hope it works. And you need buy-in from the coaching staff, because this approach contradicts decades of conventional wisdom about keeping the arm warm. The pitchers in this study preferred the cooling, despite the cultural norm. They felt better. They performed better. But changing a dugout routine requires more than just research, it requires trust that the intervention won't backfire when it matters most.

There's also the possibility that cooling works for some pitchers and not others. Individual variability is massive in all physiological interventions. Some athletes respond strongly to cold. Others don't. Some might find that cooling disrupts their feel or timing. Others might find it sharpens them. The study didn't stratify results by individual response, so we don't know if the benefits were universal or concentrated in a subset of the group. For athletes considering this approach, the recommendation is straightforward: test it in low-stakes environments first. Simulate a game in a bullpen session. Cool between innings. See how it feels. Track velocity. Monitor perceived exertion. If it works, integrate it. If it doesn't, don't force it.

The Bigger Question About Recovery Between Innings

This study opens a line of inquiry that goes beyond ice. What else could we be doing between innings to manage fatigue and preserve performance? Traditional approaches are passive. Sit down. Throw a jacket on. Wait. But passive rest might not be optimal. Active recovery, whether it's cooling, breathing protocols, compression, or structured movement, might offer advantages that passively waiting doesn't. The pitch clock research suggests that shorter rest periods might actually improve workload tolerance by reducing time under tension. The cooling study suggests that targeted interventions during rest periods can preserve output in late stages. Both challenge the assumption that more passive rest equals better recovery.

For pitchers, the application is clear. You don't have to accept late-game velocity decline as inevitable. You don't have to assume that by inning five, you're just going to be slower and more fatigued. You can intervene. You can structure your between-inning routine to actively manage the processes that drive fatigue. Cooling is one option. But the principle is broader. Recovery isn't just about resting. It's about doing the things that allow your body to reset, perform, and repeat. And if four minutes of ice can preserve 1.5 miles per hour and reduce perceived exertion by 35 percent, it's worth asking what other tools we're not using because we're stuck in the way things have always been done.

References

Bishop SH, Herron RL, Ryan GA, et al. The Effect of Intermittent Arm and Shoulder Cooling on Baseball Pitching Velocity. J Strength Cond. 2016. PMID: 24077378.

Huang JH, Chiu YC, Chang CK. Influence of Hot Environment on Pitching and Hitting Performance in Professional Baseball. J Strength Cond. 2021. PMID: 34100784.

Card RK, Liakos BJ, Schwartz JT, et al. Pitch Clock Increases Tolerated Workload Before Ulnar Collateral Ligament Injury: A Retrospective Cohort Study of Major League Baseball. Orthop J Sports Med. 2025. PMID: 40933948.

Tao B, Sun H, Li H, et al. Combined Effects of Rhodiola Rosea and Caffeine Supplementation on Straight Punch Explosive Power in Untrained and Trained Boxing Volunteers: A Synergistic Approach. Metabolites. 2025. PMID: 40278391.

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