Introduction
Pitchers all over the world experience arm pain. As a pitching trainer, I’m often asked, “I have pain at X spot or place, is this normal?” While arm pain is common among pitchers, that doesn’t mean it should be accepted — especially while throwing. Pain is a sign that something needs attention, not just part of the game. When an athlete comes to Driveline Baseball, I tend to ask, “Why did you choose us?” Lately, I have been getting the answer, “I’m wondering if you guys can figure out why my arm is hurting?” I was always told; never ask a question you don’t want the answer to.
The Limits of Motion Capture
Motion capture technology is one of the most powerful tools in baseball biomechanics and the greatest tool that’s been developed over many years here at Driveline. By tracking joint angles, velocities, and movement patterns with millimeter precision, motion capture provides deep insights into how athletes move on the mound. Coaches and trainers can use this data to identify inefficiencies, compare mechanics to those who throw harder or slower, and refine training programs to optimize performance. However, despite its sophistication, motion capture cannot directly tell you why your arm hurts.
Pain is a complex and multifaceted issue, influenced by factors beyond what motion capture can record. While motion capture excels at breaking down mechanics, it does not measure internal biological responses such as muscle fatigue, tissue stress, or inflammatory processes. Many athletes with seemingly “ideal” mechanics still can experience pain, while others with mechanical flaws remain injury-free. This gap highlights the limitations of using motion capture as a diagnostic tool for arm pain.
What Motion Capture Actually Measures
Motion capture technology is a powerful tool for analyzing an athlete’s movement with high precision. This allows coaches, trainers, and sports scientists to quantify an athlete’s mechanics, identify inefficiencies, and potential velocity outcome.
However, while motion capture provides valuable insights, it does not directly measure several critical components of movement and injury risk:
- Muscle Forces & Activation: Motion capture captures how joints move but does not measure the forces generated by muscles to create that movement. Electromyography (EMG) or musculoskeletal modeling is required to estimate muscle activation and force production. (This will be added into our assessment process this year!)
- Soft Tissue Stress & Joint Loading: While motion capture can infer joint kinetics (the forces and torques acting on a joint) when combined with force plate data, it does not directly measure stresses on ligaments, tendons, or cartilage. For example, an athlete may exhibit “high stress” movement patterns, but convention motion capture alone cannot quantify actual tissue strain or microtrauma.
- This requires a Forward Dynamics approach, which is what our R&D team has been working on for years and will deploy at some point soon!
- Neurological & Motor Control Factors: Coordination, proprioception, and reflexive adjustments are crucial to movement but are not captured in motion capture data. The central nervous system’s role in injury risk and movement efficiency requires additional testing beyond kinematic (just how something moves, not why) analysis.
- Pain & Fatigue: Motion capture data cannot determine whether an athlete is experiencing pain, compensating due to discomfort, or fatigue. These factors influence movement patterns but require subjective (based on personal feelings, opinions, or experiences) reporting, force analysis, or physiological assessments to evaluate fully.
What Motion Capture Can Do
While motion capture can’t diagnose pain, it plays a crucial role in understanding mechanical inefficiencies and potential risk factors. For example, if a pitcher exhibits excessive elbow valgus torque or inefficient hip-shoulder separation, motion capture data can highlight these trends, which may contribute to increased stress or inefficiencies over time. While not a direct predictor of injury, this information allows coaches/trainers to assess potential risk factors and make data-driven decisions to adjust mechanics, modify workload, or refine strength and mobility programs.
Additionally, motion capture provides an objective baseline for tracking an athlete’s mechanical changes over time. By comparing sessions, trainers can assess the effectiveness of mechanical adjustments, evaluate how an athlete adapts to training constraints, and ensure that improvements are sustainable.
Ultimately, while it doesn’t directly explain why an athlete experiences pain, motion capture helps bridge the gap between subjective feedback (not necessarily factual) and objective (based on facts, data, or something measurable, not influenced by personal feelings) data. It empowers athletes and trainers with deeper insights into movement efficiency, helping to reduce injury risk and optimize long-term performance.
The Best Approach to Arm Pain
It’s important to recognize that pain is complex, often with many layers!
When an athlete experiences arm pain, it’s tempting to look for a single cause and solution. However, arm pain is often the result of multiple factors, and relying solely on motion capture to diagnose the issue is insufficient. While motion capture provides valuable data on joint angles, velocities, and positions, it does not measure muscle forces, tissue health, or fatigue levels — key components in understanding pain.
A more comprehensive approach includes:
- Strength & Mobility Assessments — Identifying imbalances, weaknesses, or restrictions that could contribute to stress on the arm.
- Workload Tracking — Monitoring throwing volume, intensity, and recovery patterns to detect overuse or sudden spikes in stress.
- Medical Evaluation — Consulting with athletic trainers, physical therapists, or doctors to rule out structural issues such as ligament damage or nerve irritation.
- Recovery & Fatigue Monitoring — Tracking sleep, nutrition, and subjective soreness to understand how well the body is adapting to stress.
Pain sometimes isn’t simple and therefore the answer isn’t always easy to find. Pain is complex, which is true — pain can have many layers, including physical, emotional, and psychological aspects. While the immediate response to a cut is physical injury and nerve signals to the brain, pain can also be influenced by past experiences, stress, and even how you mentally process the injury. So, pain isn’t always as straightforward as just a physical response; it can also involve how your body and mind interpret that experience.
Conclusion
Motion capture is an incredible tool for analyzing pitching mechanics, offering precise data on joint angles, velocities, and movement patterns. However, it is not a complete solution for diagnosing injuries or identifying the root causes of pain. While motion capture provides valuable biomechanical insights, it does not directly measure tissue stress, muscle fatigue, or underlying physiological factors that contribute to discomfort or the cause of pain.
Recognizing these limitations is crucial for athletes and trainers to make informed decisions. Rather than treating motion capture data as a definitive diagnosis, it should be used as one piece of a larger puzzle — guiding adjustments to mechanics, assessing movement efficiency, and identifying potential risk factors.
To truly safeguard an athlete’s health and maximize performance, motion capture should be integrated with professionals who understand the data and strength programming, along with workload management strategies. By combining biomechanics with a holistic approach to player development, we can create more effective injury prevention strategies, optimize training interventions, and help pitchers perform at their highest level for the long term. The best ability is availability.
Written by Luke Dziados – Pitching Trainer at Driveline Tampa
