Introduction

A 2024 cross-sectional study published in the Journal of Athletic Training explored a question that doesn't get asked nearly enough in youth baseball: how does core strength, specifically through the abdominal obliques, relate to trunk and pelvis rotation in adolescent pitchers? The researchers didn't just measure general core strength or ask athletes to hold a plank for as long as possible. They tested oblique strength on both the throwing side and the glove side, then analyzed how that strength correlated with rotational mechanics during maximal-effort fastballs. Nineteen high school pitchers participated, and the findings were revealing. Three kinematic variables showed strong correlations with oblique strength. Throwing-arm oblique strength was positively correlated with maximum pelvis rotation velocity. But the glove-side obliques, the side that often gets ignored in training conversations, showed even stronger relationships. Glove-arm oblique strength was positively correlated with both maximum pelvis rotation velocity and maximum torso rotation velocity. And here's the part that matters most: these rotational improvements occurred without increases in shoulder or elbow torque, suggesting a more efficient transfer of force through the kinetic chain. The obliques weren't just helping these athletes rotate faster, they were helping them rotate better.

What the Study Found

The study design was straightforward but deliberate. Nineteen adolescent baseball pitchers were recruited and tested for abdominal oblique strength using isometric dynamometry on both the throwing and glove sides. After strength testing, each athlete threw maximal-effort fastballs while motion capture systems tracked pelvis rotation velocity, torso rotation velocity, shoulder torque, and elbow torque. The researchers were looking for relationships, not just correlations between strength and speed, but whether stronger obliques translated into more efficient mechanics without adding stress to the arm.

The results showed clear patterns. Throwing-arm oblique strength was positively correlated with maximum pelvis rotation velocity, with a correlation coefficient of 0.52. That's meaningful, but not the full story. The glove-side obliques showed even stronger relationships. Glove-arm oblique strength correlated with maximum pelvis rotation velocity at 0.69, and with maximum torso rotation velocity at 0.52. Both correlations were statistically significant, and both suggest that the glove side plays a more prominent role in driving rotational speed than many coaches or athletes might assume. To be honest, this reminds me of conversations I've had with strength coaches who program endless medicine ball throws and rotational slams, all targeting the throwing side, while the glove side gets treated like an afterthought. This study suggests that's backwards.

What makes these findings particularly valuable is what didn't happen. Despite increases in pelvis and trunk rotation velocity, there were no corresponding increases in shoulder or elbow torque. That means the athletes weren't just rotating faster and absorbing more stress downstream, they were transferring energy more efficiently. The system was working better. Average contralateral trunk tilt at maximum external rotation remained at 26.1 degrees, well below thresholds that have been linked to injury risk in other research. The athletes were rotating harder, but not in a way that compromised their mechanics or overloaded their joints.

There was one finding that might seem disappointing at first glance: oblique strength was not directly associated with ball velocity in this adolescent sample. The athletes with stronger obliques rotated faster, but the radar gun didn't immediately reflect it. But that disconnect might be the most important part of the story. Adolescent pitchers are still developing the neuromuscular coordination, timing, and sequencing that allow rotational speed to translate into ball velocity. The obliques may be laying the foundation for efficient movement, even if the performance outcomes don't show up yet. And if that's the case, prioritizing oblique strength early in an athlete's development might be one of the most underrated investments a coach or parent can make.

Why This Information Is Important

This study matters because it identifies a specific, trainable quality that improves rotational mechanics without increasing arm stress. That's rare. Most interventions that increase velocity also increase torque. Most strategies that improve sequencing come with tradeoffs. But stronger obliques, particularly on the glove side, appear to offer a way to rotate faster and more efficiently without asking the arm to pay the price. A 2025 study on Australian baseball pitchers found that later upper trunk rotation relative to the pelvis was linked to higher ball velocity and spin rate, but also greater shoulder loading. The researchers described it as a performance-risk tradeoff, where efficient sequencing amplifies velocity but mismanaging that sequence amplifies stress. The obliques are the muscles responsible for controlling that sequence. If an athlete lacks the strength to stabilize the pelvis and regulate trunk rotation, they can't access the timing patterns that define efficient mechanics. The system breaks down before it ever gets a chance to work.

We also know from research comparing professional and high school pitchers that rotational efficiency is what separates levels. A 2018 study published in the Orthopedic Journal of Sports Medicine analyzed 37 high school and 40 professional pitchers and found that professionals threw harder but had similar or lower normalized elbow torque compared to high school athletes. The difference wasn't arm speed, it was trunk and pelvis rotation. Professionals used significantly greater rotation across all phases of the delivery, and greater trunk and pelvis rotation correlated with lower elbow torque. High school pitchers, in contrast, relied more on the arm to generate velocity, placing them at higher injury risk. The implication is clear: learning to rotate efficiently early in development may be one of the most protective things a young pitcher can do. And the obliques are central to that process.

Another 2025 study reinforced the importance of pelvic control in pitching performance. Researchers found that pitching velocity was most strongly associated with transverse-plane pelvic control and dynamic pelvic-trunk coordination across specific phases of the delivery. Sagittal-plane control showed no significant relationship with velocity, reinforcing the specificity of transverse-plane movement in rotational athletes. The obliques are the primary muscles responsible for controlling transverse-plane motion at the pelvis and trunk. If an athlete can't stabilize and regulate rotation through those segments, they can't access the coordination patterns that drive performance. Training programs that ignore oblique strength are leaving one of the most important qualities on the table.

We also know that fatigue disrupts the very coordination patterns that oblique strength supports. A 2025 study on muscular fatigue in adolescent baseball pitchers found that after just 35 pitches, torso rotation angle decreased by 1.3 degrees at ball release, and hip-to-shoulder separation dropped by 1.4 degrees. Timing of maximum shoulder internal rotation velocity also decreased, suggesting altered sequencing. Fatigue doesn't just reduce output, it disrupts the kinetic chain. And when the kinetic chain breaks down, the arm has to compensate. Building oblique strength and endurance may help athletes maintain efficient sequencing under fatigue, reducing the mechanical drift that increases injury risk as pitch counts climb.

There's also evidence that the timing of trunk rotation relative to pelvic rotation directly influences efficiency. A 2021 study on stride length and ball velocity found that a shorter time interval between peak pelvic rotation velocity and peak trunk rotation velocity was associated with improved biomechanical efficiency. The obliques are the muscles that control that timing. If an athlete lacks the strength to decelerate the pelvis and accelerate the trunk in coordinated sequence, the timing gets sloppy. Energy leaks. Velocity suffers. And the arm works harder than it should.

How This Information Can Be Applied

The practical takeaway here is that oblique training, particularly on the glove side, should be prioritized in developing pitchers. That doesn't mean endless sets of side planks or Russian twists. It means training the obliques to do what they're supposed to do during pitching: stabilize the pelvis, control transverse-plane rotation, and coordinate the transfer of energy from the lower body through the trunk and into the arm. Exercises that challenge rotational control under load, resisted trunk-pelvis dissociation drills, and isometric holds under rotational demand are all tools that can develop the qualities this study identified.

One approach is to use exercises that mimic the demands of the pitching delivery. Single-leg rotational med ball throws, where the athlete has to stabilize the pelvis on one leg while rotating the trunk, challenge the obliques in a way that transfers to the mound. Pallof presses, particularly when performed in a split stance or with a step, teach the obliques to resist rotation while the limbs move, which is exactly what happens during the delivery. Anti-rotation exercises, where the athlete resists an external rotational force, build the eccentric strength needed to decelerate the pelvis and trunk at the right moments in the kinetic chain.

It's also worth acknowledging that this study found stronger relationships on the glove side than the throwing side. That's not an accident. The glove side obliques are responsible for decelerating the pelvis and controlling the rate at which the trunk rotates. If those muscles are weak, the pelvis rotates too early, the trunk follows too quickly, and the sequencing that defines efficient mechanics falls apart. Training the glove-side obliques isn't just about balance or symmetry, it's about giving the athlete the ability to control the timing of their delivery.

For coaches working with adolescent pitchers, it's also important to recognize that oblique strength may not produce immediate velocity gains. This study found no direct correlation between oblique strength and ball velocity in the adolescent sample. But velocity is the outcome of a coordinated system, not a single input. Oblique strength enables better sequencing, which enables better energy transfer, which eventually enables higher velocity. The gains might be delayed, but they're foundational. And for young athletes who are still developing the coordination and timing that define efficient mechanics, building that foundation early might be the difference between sustainable velocity gains and compensatory patterns that lead to injury.

Finally, oblique training should be integrated into a broader strength and conditioning program that addresses the entire kinetic chain. The obliques don't work in isolation. They function as part of a system that includes the hips, the lower body, the shoulders, and the arm. A pitcher with strong obliques but weak hips won't be able to generate the pelvic rotation that the obliques are supposed to control. A pitcher with strong obliques but poor shoulder strength won't be able to decelerate the arm efficiently after ball release. The goal isn't to maximize oblique strength for its own sake, it's to build a system that works together, where each segment contributes to efficient energy transfer and no single segment absorbs more stress than it can handle.

Conclusion

This study doesn't claim that oblique strength is the key to velocity or the secret to injury prevention, and neither should we. But it does provide clear evidence that stronger obliques, particularly on the glove side, improve rotational mechanics in adolescent pitchers without increasing arm stress. That's a rare combination. Most interventions that improve performance come with tradeoffs. This one appears to offer efficiency without cost. The fact that oblique strength didn't correlate directly with velocity in this sample might be the most important finding of all. It suggests that the adaptations happening at the level of trunk and pelvis rotation are foundational, not immediate. They're building the infrastructure that will support velocity gains as the athlete matures, rather than forcing gains through compensation or overload. For coaches, parents, and practitioners working with developing pitchers, the message is clear: don't ignore the glove side. Don't treat the obliques as an accessory. And don't expect the radar gun to tell you whether your training is working. Sometimes the most important adaptations are the ones that show up in sequencing, coordination, and efficiency, long before they show up in miles per hour.

References

Eilen HT, Kokott W, Dziuk C, Cross JA. Relationship of Abdominal Oblique Strength on Biomechanics in Adolescent Baseball Pitchers. J Athl Train. 2024. PMID: 39480789.

Australian Study. Delay The Trunk For Added Velo. J Sports Sci. 2025.

Luera MJ, Dowling B, Magrini MA, et al. Role of Rotational Kinematics in Minimizing Elbow Varus Torques for Professional Versus High School Pitchers. Orthop J Sports Med. 2018. PMID: 29581995.

Wang SM, Chen SH, Chen HY, et al. Pelvic Control and Pelvic-Trunk Coordination as Key Determinants of Pitching Velocity in Baseball Pitchers. Orthop J Sports Med. 2025.

Johnson AL, Kokott W, Dziuk C, Cross JA. Assessment of Muscular Fatigue on Hip and Torso Biomechanics in Adolescent Baseball Pitchers. Strength Cond. 2025. PMID: 40440541.

Manzi JE, Dowling B, Dines JS, et al. The Association of Stride Length to Ball Velocity and Elbow Varus Torque in Professional Pitchers. J Sports Sci. 2021. PMID: 34240663.

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