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Here's something that should make every pitching coach and athlete pay attention: a simple single-leg step-down test, performed in a controlled setting with no ball in hand, can predict which pitchers are at elevated risk for high elbow torque and low velocity. A 2025 study by DeZee and colleagues explored whether lumbopelvic stability during a single-leg step-down (SLSD) could predict elbow stress during pitching. Using a dual-task version of the SLSD that included cognitive load via the Stroop test, researchers analyzed pelvic and trunk motion in 44 NCAA Division I pitchers. What they found was striking. Pitchers who displayed greater transverse-plane motion of the trunk during the SLSD were 2.9 times more likely to fall into a high-torque, low-velocity group. Similarly, increased transverse-plane motion of the pelvis led to 2.5 times higher odds of being in that same inefficient pattern. The SLSD, a test that takes less than a minute to administer, effectively flagged pitchers whose mechanics were costing them both performance and durability.
The researchers divided 44 NCAA Division I pitchers into two clusters based on their pitching biomechanics: a low-torque, high-velocity group and a high-torque, low-velocity group. They then had each pitcher perform a single-leg step-down test, both with and without a cognitive task (the Stroop test, which requires athletes to name colors while ignoring conflicting word stimuli). The idea was to simulate the divided attention demands of actual pitching, where athletes must process information, make decisions, and execute complex movements simultaneously.
What emerged was a clear pattern. Pitchers who rotated more in the transverse plane during the SLSD, meaning their trunk and pelvis twisted rather than staying controlled, were far more likely to belong to the inefficient, high-stress group. The odds ratios were significant: 2.9 times greater for trunk rotation and 2.5 times greater for pelvic rotation. Interestingly, frontal-plane and sagittal-plane motions during the SLSD had no predictive value for elbow torque. It wasn't about how much they leaned side to side or how far forward they tipped. It was specifically about rotational control, or the lack of it.
The authors suggested that gluteal and core deficits may underlie this poor transverse-plane control. When the muscles responsible for stabilizing the pelvis and trunk under load aren't doing their job, the body finds another way to complete the task. That compensation shows up as rotation. And if it shows up in a controlled, non-throwing environment, there's a good chance it's showing up on the mound too.
While there's never a single cause of injury or inefficiency, the fact that pitchers with more trunk and pelvic rotation during a simple SLSD showed higher elbow torque and lower velocity is tough to ignore. It's not that rotation is inherently bad. Pitching is a rotational activity, after all. But when rotation shows up in a controlled, non-throwing task where the goal is to maintain stability, it may reveal compensations or deficits upstream. The movement isn't supposed to be there, and when it is, it tells us something about the system's ability to control force.
This finding aligns with a 2025 study on pelvic control and pitching velocity that found transverse-plane pelvic variability had the strongest negative correlation with velocity (r = –0.78). Pitchers who couldn't control pelvic rotation during their delivery lost up to 4 mph compared to those with tighter rotational control. That same study used single-leg balance tests and found that poorer transverse pelvic control on both the stride leg and drive leg was linked to lower velocity, supporting the use of these tests as functional screening tools. And just like the SLSD study, sagittal-plane control showed no significant relationship with velocity. The transverse plane is where the action is, and it's where deficits show up most clearly.
Research on oblique strength adds another layer to this conversation. A 2024 study on adolescent pitchers found that glove-side oblique strength was positively correlated with both maximum pelvis rotation velocity and maximum trunk rotation velocity, and critically, these rotational improvements occurred without increases in shoulder or elbow torque. Athletes with stronger obliques on the glove side rotated faster and did so more efficiently. The authors suggested that glove-side obliques may play an early role in the kinetic chain by contributing to elastic energy storage during hip-to-shoulder separation. If the core can't do its job, the rotation still has to come from somewhere, and that somewhere is often the arm.
The consequences of poor sequencing become clearer when we look at research comparing professional and high school pitchers. A 2018 study found that professionals generate more velocity with less relative elbow torque by using greater trunk and pelvis rotation. High school pitchers, by contrast, relied more heavily on the arm. When normalized for body size, high school pitchers actually experienced greater torque at maximum external rotation than professionals, despite throwing at the same or lower velocities. The more profound lesson here is that efficiency comes from coordination. Professional pitchers time and sequence their hips and trunk so the arm simply transfers energy rather than creating it. When that sequencing breaks down, the arm picks up the slack, and the elbow pays the price.
Research on youth athletes reinforces the idea that simple movement screens can identify risk before injury occurs. A 2024 longitudinal study tracked over 250 elementary school pitchers across one year to see whether deep squat performance could predict future medial elbow injuries. Players who failed the squat tests, particularly the backward squat variation with hands behind the back, were significantly more likely to develop elbow problems. The success rate on the squat test was 22.6% lower in the injured group compared to the non-injured group. The backward squat challenges multiple systems at once: postural stability, balance, coordination, and mobility. For developing pitchers, deficiencies in these areas can interrupt the efficient transfer of force from the ground up, leaving the arm to absorb the slack. The elbow might be where pain shows up, but it's rarely where the problem begins.
The fatigue research ties this all together. A 2025 study on adolescent pitchers found that after just 35 pitches, pelvic rotation velocity dropped and hip-to-shoulder separation decreased. Fatigue doesn't just happen in the arm. It starts in the hips. When hip rotation and pelvic velocity drop, the torso compensates, disrupting energy transfer and forcing the shoulder and elbow to absorb more stress. If an athlete's baseline rotational control is already compromised, as the SLSD might reveal, the margin for error under fatigue becomes even smaller. The deficits that show up in a simple step-down test don't stay in the weight room. They follow the athlete onto the field, and they get worse as the game goes on.
The practical takeaway here is straightforward. The single-leg step-down, especially when combined with a cognitive task like the Stroop test, offers a simple and accessible way to screen for rotational control deficits that may be affecting pitching efficiency and elbow health. If a pitcher displays excessive trunk or pelvic rotation during this test, it's a signal that targeted intervention is needed.
That intervention should focus on the lumbopelvic-hip region, specifically the muscles responsible for controlling rotation under load. Gluteal strength, particularly the gluteus medius and maximus, plays a critical role in stabilizing the pelvis during single-leg activities. Core strength, especially the obliques on the glove side, contributes to efficient trunk rotation and energy transfer. Drills involving single-leg balance under rotational challenge, resisted trunk-pelvis dissociation, and isometric holds under rotational load may help reinforce the coordination patterns observed in higher-velocity, lower-stress throwers.
The key is specificity. Training sagittal-plane movements like squats and deadlifts is valuable, but this research suggests that transverse-plane control is what separates efficient pitchers from inefficient ones. Programming should reflect that. Anti-rotation exercises, Pallof presses, rotational medicine ball work with an emphasis on deceleration, and single-leg stability drills that challenge the athlete to resist rotation can all contribute to building the qualities that matter most on the mound.
For coaches and trainers, integrating the SLSD into regular screening protocols provides a low-cost, high-yield way to monitor athletes over time. Changes in rotational control during the SLSD may indicate fatigue accumulation, incomplete recovery, or developing deficits that need to be addressed before they manifest as performance drops or injury. The test doesn't require expensive equipment or a biomechanics lab. It requires a step, a camera, and an eye for movement quality.
The SLSD study reinforces a principle that has been emerging across the research for years: the elbow is often the victim, not the cause. Pitchers who can't control rotation in a simple, controlled task are nearly three times more likely to show elevated elbow stress and reduced velocity on the mound. That rotation, appearing where it shouldn't, reveals deficits in the muscles and coordination patterns that are supposed to stabilize the system under load. The good news is that these deficits are trainable. Strengthening the lumbopelvic-hip region, emphasizing transverse-plane control, and using simple screening tools like the SLSD can help identify at-risk athletes before injury occurs and guide intervention toward the qualities that actually matter. A simple tool can offer surprisingly clear insight into where stability is lacking and how to target it.
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