The Importance of Monitoring Elbow Stress in Pitchers

In baseball, the stress placed on a pitcher’s elbow is a crucial factor in long-term performance and injury prevention. With elbow injuries, particularly UCL tears, becoming increasingly common, understanding the biomechanical forces behind different pitch types can help coaches make more informed decisions about workload management, throwing mechanics, and training programs.

A recent study (PMID: 39836440) examined how different pitch types—fastballs, curveballs, change-ups, and sliders—impact elbow varus torque, loading rate, and cumulative torque. These factors all contribute to the overall stress placed on the arm, affecting both short-term performance and long-term durability.

Key Study Findings

Before diving into practical applications, let’s summarize the critical findings from the study:

• Fastballs had the highest ball velocity (40.4 ± 0.6 m/s) and the greatest peak elbow varus torque (90.1 ± 3.5 N·m), meaning they generate the most immediate stress on the elbow.
• Change-ups had the lowest peak torque (81.3 ± 2.4 N·m) but had the highest cumulative torque, meaning that while each pitch exerts lower force, the total load on the elbow over time is substantial.
• Curveballs and sliders produced intermediate torque values but still contributed significant stress to the elbow.
• Loading rate, which measures how quickly force is applied, was highest in fastballs (780.7 ± 65.4 N·m/s), reinforcing their potential for acute stress.

How to Apply These Findings to Coaching and Training

1. Don’t Rely on Peak Torque Alone—Consider Cumulative Stress

One of the biggest takeaways is that while fastballs generate the most peak torque, change-ups create more cumulative stress over time. This means that pitchers with high change-up usage may experience elbow wear and tear that builds up gradually rather than manifesting in an acute injury.

Application:

• Coaches should track not just pitch counts but also the types of pitches thrown.
• If a pitcher is throwing an excessive number of change-ups, their elbow might be under significant stress—even if peak torque readings suggest otherwise.

Tip: If a pitcher is known for a high-volume change-up approach, incorporating recovery strategies, rest periods, and proper strengthening exercises can counteract the cumulative stress effects.

2. Adjust Pitch Selection Based on Fatigue & Recovery

With loading rate being highest in fastballs, these pitches place rapid and intense stress on the elbow. When a pitcher is fatigued, their ability to properly stabilize the joint may be compromised, increasing the likelihood of injury.

Application:

• Pitch selection should be adapted based on where a pitcher is in their workload cycle.
• After high-intensity outings, limiting high-loading-rate pitches like fastballs may help reduce acute stress on the elbow.

Tip: Monitor recovery using grip strength tests, arm care assessments, or even subjective fatigue reports from pitchers. If a pitcher shows signs of fatigue, modifying pitch sequencing to reduce fastball volume may be beneficial.

3. Incorporate Strength Training to Offset Elbow Stress

One of the best ways to mitigate the stress caused by different pitch types is to improve strength and mechanical efficiency in the shoulder, forearm, and elbow stabilizers.

Application:

• Training should emphasize joint stability and endurance, particularly for pitchers who rely on fastballs or change-ups.

Strength Training Focus Areas:

• Scapular stability (e.g., banded YTWs, wall slides)
• Forearm & grip strength (e.g., wrist curls, rice bucket exercises)
• Eccentric elbow loading (e.g., reverse throws, slow deceleration work)

Tip: Incorporate isometric holds and controlled eccentrics in training to help pitchers handle high torque levels more efficiently.

4. Rethink Workload Management Beyond Just Pitch Counts

Traditionally, pitch counts have been the primary workload metric for protecting pitchers. However, this study suggests that the types of pitches thrown may be just as important as the number.

Application:

• Instead of treating all pitches the same, consider adjusting workload expectations based on pitch profile.

Example:

• A pitcher who throws 80% fastballs may need longer recovery than one who mixes pitches evenly.
• A pitcher with a high percentage of change-ups may not show immediate elbow stress but could accumulate excessive load over a season.

Tip: Use data tracking tools (e.g., Motus, TrackMan, Rapsodo) to monitor not just pitch volume but the stress each type of pitch is creating.

High-Specialized Training with Objective Data

By integrating data-driven workload monitoring with arm care testing and grip strength assessments, we can take a much more specialized approach to training and recovery. Utilizing objective tools like the ArmCare unit (armcare.com) and FlexPro Grip (flexprogrip.com) allows for precise tracking of fatigue, strength imbalances, and recovery needs.

By coupling this data with pitch-type information, coaches and trainers can:

• Assess whether an athlete’s grip strength or arm health is declining due to cumulative stress.
• Identify early warning signs of fatigue before a mechanical breakdown occurs.
• Adjust throwing programs to reduce unnecessary torque while maintaining velocity gains.
• Build individualized recovery protocols based on real-time data rather than subjective feel.

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