Rotational Power Using the Keiser Machine – A Review

Every summer at The Florida Baseball ARMory, we turn our training environment into a living laboratory. Athletes from around the world come to chase gains in velocity, command, and durability, and in the process, they help us uncover new insights about how the body truly creates power. This year, our Director of Performance, Alan Kolb, led a case study using the Keiser functional trainer to explore one simple but critical question: does rotational power in the trunk translate to velocity on the mound? The results, drawn from 20 pitchers ranging from high school to Division I, revealed some fascinating patterns and practical takeaways for coaches and athletes alike.

Summer training at the ARMory is an experience unlike any other. Athletes travel from across the world, bringing unique backgrounds and stories, yet all united by one purpose: to become the best players they can be. From high schoolers to Power Four Division 1 arms, they train side by side in an environment fueled by competition, camaraderie, and relentless work. The atmosphere hums with energy. Music pumping, sweat dripping, and athletes driving each other toward new standards of excellence.

When you work with as many athletes as we do in a short span, patterns begin to emerge. One of the most consistent amongst collegiate athletes? Players arriving strong, but stiff and uncoordinated. They can grind through endless trap bar deadlifts and heavy squats, but when asked to move fast or into particular ranges of motion, the wheels come off. No one denies that strength for athletes is critical, but when the pursuit of heavy maxes becomes the only pursuit, athletes often trade mobility, speed, and skill development for barbell numbers.

Strength is the foundation, but power is the bridge. Power lives at the intersection of strength and speed. Too often, athletes and coaches spend months stacking strength without ever layering in the speed component. Think about it: no coach or scout has ever written off a player for being “too powerful,” but countless athletes have been overlooked because they never learned to apply their strength at game speed. Power is what happens when force meets velocity (Power = Force × Velocity).

This summer, we set out to explore rotational power using our Keiser functional trainer. While this project is best described as an applied case study within our summer training environment, not a controlled research experiment, the findings offer meaningful insight into how trunk and abdominal power may influence performance on the mound. By testing across a diverse group, from rising high schoolers to elite college arms, we aimed to answer a simple but important question: Does rotational power created in the trunk translate to velocity on the mound, or does it scatter with no clear connection?

The Abs: Their Role and Importance for pitchers

It would be naïve not to first touch on the abdominals and their role in athletic movement. In throwing, the abdominal muscles are often misunderstood. Unlike the glutes or lats, which are designed to generate large amounts of force, the abs function more like precision regulators. They operate within a narrow bandwidth, coordinating trunk rotation, stabilizing the pelvis, and bridging force transfer between the lower half and the upper body.

When the abs do their job well, energy flows seamlessly through the kinetic chain. When the abdominals are pushed out of their optimal length, compensations emerge and stress on the elbow and shoulder increases. The challenge with the abdominals is that their functional sweet spot is razor thin.

Much of traditional abdominal training misses the mark. Endless crunches and sit-ups build superficial strength but do little to develop the precise, elastic, and timing-sensitive role the abs must play in throwing. To unlock their real potential, abdominal training must respect context: variability, timing, and the constant demand to transfer energy at game speed.

How:

For this study, we utilized our Keiser functional cable machine, which allows us to quantify force, velocity, and ultimately power output. The Keiser uses Pneumatic resistance, which helps to minimize inertia and momentum, and better allows athletes to accelerate the load through the full range of motion than traditional methods.

With the Keiser, we focused on two key measures:

• Peak Power: the highest level of power achieved within a set.
• % of Peak Power: the percentage of that peak achieved on each rep, providing insight into consistency, fatigue, and repeatability.

Together, these metrics gave us both the ceiling (how much an athlete could maximally produce) and the reliability (how well they could sustain it across multiple attempts).

To explore how rotational power expressed itself, we divided testing into two conditions across three differing loads (8%, 10%, and 12% of bodyweight). In both conditions, athletes stood in a hinged position with the Keiser cable set slightly above sternum height:

• Strict reps: Feet “glued” to the floor. Athletes could rotate explosively, but no lifting the lead leg, no coiling, no counter-rotation.
• Anyway reps: Athletes were free to move however they wanted. Examples include lead leg lift, coiling, and counter-rotation.

Each pitcher performed three strict reps and three “anyway” reps at each load, giving us a clear picture of both constrained strategies and self-organized strategies.

The findings:

First, we collected data on rotational power using the Keiser machine. Then, we paired those results with fastball velocities captured during bullpen sessions on our TrackMan system, aligning both sets of data by date. During summer training, athletes’ time at the ARMory varied considerably. Summer ball, prior commitments, rest periods, and family vacations meant that no two training windows looked the same, but each athlete was tested at the beginning of training and at the end. When we calculated the gap between the initial Keiser test and the follow-up, the average interval across all athletes was approximately 33 days.

First, let’s talk about velocity gained on the mound. Out of the 20 pitchers who fit the test parameters, thirteen athletes gained velocity in both their average (sitting) fastball and their max velocity. On average, this group improved their average velocity by +2.1 mph, while their max velocity climbed by +2.4 mph. The biggest individual jump came from one collegiate pitcher who added +4.1 mph to his top fastball.

The remaining seven pitchers did not show increases in their average velocity, but each recorded gains in their max velocity. On average, this group improved their top fastball by +0.9 mph, with the largest single increase being +1.3 mph. In other words, their average FB stayed the same, but their max velo grew. It’s worth noting that training goals varied across the group. Some athletes prioritized pitch design, command, or workload management. These factors help explain why velocity gains weren’t uniform across the board.

The most striking result from the study was the consistency: all 20 pitchers improved their rotational power on the Keiser machine over their training window.

It’s important to note that NONE of these athletes trained Keiser chops or rotations directly. We did however program a variety of exercises that used waterbags/balls, medballs and ropes/chains which all included rotational variations. On top of this, they were completing a lot of skill work as noted above.

The Bigger Picture – Implications for Coaches and Athletes

The most consistent outcome from this case study was that every athlete improved their rotational power. While increases in pitch velocity often coincided with these gains, the improvements also reflected deeper changes in skill and movement patterns. That includes better control of the lead leg, more efficient hinging, and cleaner sequencing. Strength and power may provide the foundation, but without coordination, sequencing, and adaptability, that foundation rarely translates into performance on the field.

For coaches and athletes, the takeaway is simple: training must move beyond the endless pursuit of heavier lifts or raw horsepower. It’s not strength versus skill, it’s the integration of multiple qualities. The athletes who made the biggest jumps weren’t merely stronger; they became better movers. They learned to generate power in the trunk and transmit it seamlessly through the kinetic chain. This requires training abdominals for timing and transfer, not just force, and creating drills that challenge them under dynamic conditions.

The bigger picture is this: strength builds the base, but it is only when speed, coordination, and skill are woven together that training produces true performance. Weight room numbers matter, but the numbers that matter most are on the mound. In the end, the weight room is a starting point, but true success is measured 60 feet, 6 inches away.

Limitations of Study:

While the findings from this case study provide valuable insights, there are several limitations to consider. The sample size was relatively small (20 pitchers), and although it included a range of athletes from high school to Division I, the group is not large enough to generalize across all populations. Training goals also varied, with some athletes prioritizing velocity while others focused on pitch design, command, or rehabilitation, which likely influenced the results. Despite these limitations, we hope this case study helps paint a clearer picture of how improvements in rotational power can support athletes, not as the sole ingredient for success, but as one important piece in the broader puzzle of performance development.