
The Relationship Between Decision Timing and Swing Biomechanics in Baseball
By Ken Cherryhomes
There is a widespread belief that mechanical perfection is the key to batting success. Traditional swing training focuses heavily on biomechanics—the assumption being that if a player’s swing mechanics are “high-level”, contact with the ball will naturally follow. However, this belief is an oversimplification that overlooks a critical factor: decision timing. While the mechanics of a swing play a significant role, the decision of when to swing is equally, if not more, important.
Decision Timing Versus Biomechanics
When a hitter faces a pitcher, two key aspects govern their ability to make contact with the ball: swing mechanics and the timing of their decision to swing. Swing mechanics involve the physical actions required to move the bat through the hitting zone, while decision timing involves when the hitter initiates their swing.
When discussing swing biomechanics, it’s important to recognize the natural process of swing development and how hand/eye coordination contributes to refining mechanics. Hand/eye coordination is an innate skill that allows us to perform precise actions, like reaching for and grasping an object, without consciously thinking about the biomechanics involved. Similarly, as hitters develop their swings, the body naturally refines its mechanics through practice. Bernstein observed that novice learners often reduce degrees of freedom, constraining movement to maintain control. However, as skill improves, the degrees of freedom open up, allowing for smoother, more efficient, and adaptable motion. When primary constraints like timing are reduced, the body can better optimize mechanics, leading to a more fluid, effective and intent driven swing.
For a batter who has developed sound mechanics and is accustomed and efficient at hitting 70 mph pitches—the core requirement for transitioning to higher velocities (e.g., 90 mph pitches) is not to alter the swing itself, but to modify the timing of the swing initiation. This same premise applies to hitting pitches that arrive at different locations in the hitting zone, as the bat and ball arrive at different times depending on the location and doesn’t require modifying the swing mechanics. The physics of the bat-ball interaction and the spatial requirements for intersection, the way the bat and ball connect, and the space where they meet, remain unchanged, but as pitch velocity increases, the hitter has less time to make the decision to swing. So long as the batter’s swing is time efficient, isn’t long and needlessly time consuming, this presents a challenge not of mechanics, but of decision timing.
Adjusting to Faster Pitching
When a hitter transitions from facing 70 mph pitches to 90 mph pitches, the primary adjustment lies in when to swing, not how. If the swing mechanics are efficient, the mechanics used at 70 mph should still work at 90 mph. However, the decision to initiate the swing must occur earlier, as the hitter has less time to react to the faster pitch.
This concept also applies to different pitch locations and types. For example, an inside pitch requires a different decision timing than an outside pitch at the same velocity. Similarly, fastballs and change-ups, despite their velocity differences, demand differently timed swings, not different mechanics. We don’t have different swings for different pitch locations, types, or velocities—just differently timed swings.
If the swing time itself is inefficient—taking too long to move from load to contact—mechanical adjustments may be necessary. For instance, a swing that takes 180ms to complete might work well for 70 mph pitches because the batter has more time to react. However, that same 180ms swing is likely too slow for 90 mph pitches, as the increased pitch velocity leaves less time for the batter to make contact. In contrast, if the swing time is more efficient—around 150ms—the mechanics remain sound, and the primary challenge becomes adjusting the decision timing to account for the faster pitch speed.
A high-level high school batter who regularly faces and handles 90 mph pitches effectively provides a practical example of this principle. It stands to reason that the same swing, when timed differently, could successfully handle pitches at 95 mph or higher. The mechanics of the swing wouldn’t need to change, but the decision of when to initiate the swing would have to adjust to the increased velocity.
Syncing Load Mechanics with Reaction Timing Fallacy
There are those who believe that syncing the batter’s load mechanics with the pitcher’s windup and release will automatically take care of the swing’s reaction timing. While syncing can aid in timing preparation, and is indeed an aspect of timing, focusing on this aspect solely, overlooks the critical component of decision timing. Reaction timing doesn’t fall into place just because the load is synced with the pitcher. The batter still needs to consciously decide when to initiate the swing based on factors such as pitch speed, trajectory, and location, all of which can vary with each pitch.
If It Isn’t Mechanics but Decision Timing, Why Do Some Batters Still Fail to Progress?
If mechanics remain constant and decision timing is the primary factor that needs adjustment, why do so many batters struggle to progress? The answer lies in the psychological aspect of hitting. As pitch velocities increase, batters face reduced reaction times and greater consequences for failure, which introduces mental pressure and urgency. This psychological strain often leads to breakdowns in performance.
The key to success lies in timing excellence, not mechanical adjustments. Batters who can mentally manage the urgency and pressure of reduced event time are more likely to succeed. Confidence plays a critical role here—confidence is built on success, but success also hinges on confidence. This cycle becomes a core contributor to a batter’s psychological resilience or breakdown. Ultimately, the ability to time a swing correctly under pressure, rather than the pursuit of perfect mechanics, is the true differentiator between success and failure.
Timing as a Trainable Skill
This understanding highlights an important distinction: while mechanics are critical, they alone do not guarantee success. Decision timing must be treated as a separate, trainable skill. The batter must not only refine their swing mechanics but also hone their ability to make precise, timely decisions under pressure. This shift in focus challenges the traditional training philosophy that often lumps decision-making into a vague category of “reaction time,” without recognizing it as a distinct skill that can be consciously developed.
Batters already engage in timing training, but often in a largely unstructured way. During batting practice, whether from a live arm or machine pitch, the batter correlates their success or failure to their perception of when the swing was initiated and the point of contact. Their proprioception—where their hands and barrel are at contact, the depth of contact, and the timing of the swing decision—all contribute to memory formation. This spatial and temporal awareness enables batters to repeat successful decisions and form deeper memories through repetition.
The key to structured timing training is identifying collision points for specific pitch locations. These collision points remain constant, unaffected by pitch velocity. By understanding these points, the batter can effectively close the event time loop, where the beginning and end points of the event (swing initiation and ball-bat contact) become solvable and repeatable through practice.
Conclusion
In hitting development, there is a nuanced relationship between swing mechanics and decision timing. While traditional training tends to emphasize mechanical perfection, the ability to make timely swing decisions is equally crucial. As pitch velocity increases, the primary adjustment required is not in the mechanics of the swing itself but in the timing of the decision to swing. Only if the swing time is inefficient would mechanical adjustments be necessary.
This understanding also highlights the importance of training decision timing as a separate, structured skill, addressing not only the physical aspects but also the psychological factors that influence performance. By treating timing as a skill that can be developed both mentally and physically, hitters can improve their ability to succeed against faster pitching and perform under pressure.