Unlocking Shoulder Mobility: How It Impacts Performance in Baseball and Softball Players

By Kathy Ryan-Ceisel, PT MHS

Overhead Throwing Specialist

Owner Athletic Edge and Wellness

Shoulder mobility is crucial for all baseball and softball athletes, but especially for pitchers and outfielders who work through extreme ranges of motion every throw.

Good shoulder mobility allows for efficient movement, better performance, and reduced injury risk. Because the shoulder is the most mobile joint in the body, it must maintain a delicate balance of mobility and stability to handle the high demands of throwing.

Repetitive throwing naturally changes muscle balance around the shoulder and elbow. These changes need to be monitored in-season and addressed during the off-season to prevent overuse injuries.

Below, we’ll break down the most common mobility deficits that impact throwing performance — and what they mean for your arm health.

⚾ 1. Shoulder Internal Rotation Deficit (GIRD)

Description: Internal rotation allows the arm to reach behind the back — ideally touching the opposite shoulder blade with ease. GIRD (Glenohumeral Internal Rotation Deficit) occurs when the throwing arm loses internal rotation compared to the non-throwing arm.

Impact: Loss of internal rotation disrupts the deceleration phase of throwing, forcing the elbow and shoulder to absorb more stress. This often leads to medial elbow pain and increases risk for UCL injuries.

Research Findings:

• 🧠 Mike Reinold (2008) found that pitching leads to immediate reductions in internal rotation and total shoulder motion — lasting up to 24 hours post-throwing and up to 4 days to return to baseline.

• Chronic loss of internal rotation increases elbow and shoulder pain over time.

Injury Risk: For each degree of internal rotation lost, the risk of shoulder injury rises significantly, contributing to issues like rotator cuff strains and shoulder impingement.

💪 2. Loss of Shoulder External Rotation

Description: External rotation lets you reach behind your head and touch the opposite shoulder blade. It’s essential during the “cocking phase” of throwing when the arm loads into extreme external rotation.

Impact: Reduced external rotation limits power generation, decreases throwing velocity, and increases force on the elbow and shoulder.

Research Findings:

• Greater external rotation allows more elastic energy storage, translating to higher throwing velocity.

• Each degree of lost external rotation increases elbow injury risk by 7%.

• Wilk et al. (2015) found pitchers with external rotation deficits were:

  • 2.2x more likely to land on the injured list for shoulder injury

  • 4x more likely to require shoulder surgery

• Camp et al. (2017) showed that losing more than 5° of external rotation significantly increases elbow injury risk.

Takeaway: Even though pitchers often develop increased ER from throwing, a loss of this adaptation breaks the balance between mobility and stability — raising injury risk.

🧍‍♂️ 3. Loss of Shoulder Flexion

Description: Shoulder flexion is raising your arm in front of the body (0°–180°). It’s essential for proper arm positioning during throwing and fielding.

Impact: Reduced flexion limits the ability to achieve optimal arm angles, affecting velocity, accuracy, and arm path.

Research Findings:

• A 5° loss of flexion increases injury risk 2.8x.

• Every degree of lost flexion raises elbow injury risk by 9%.

• During deceleration, the latissimus dorsi (lat) works eccentrically to slow the arm. Over time, tightness or shortening of the lat limits shoulder flexion.

Functional Consequences: Lat tightness pulls the humerus down and back, restricting overhead motion and causing compensations such as:

• Excessive lumbar extension (arching the back)

• Overuse of the elbow and biceps

Key Takeaway: Improving lat and thoracic spine mobility is one of the quickest ways to restore shoulder flexion and reduce post-throw stiffness.

💥 4. Loss of Elbow Extension

Description: Loss of elbow extension (inability to fully straighten the arm) is common in pitchers due to repeated eccentric stress during deceleration and follow-through.

Impact: Even a few degrees of loss affects throwing mechanics, release point, and velocity — and can lead to inflammation in the joint.

Research Findings:

• Professional pitchers often lose 5°–8° of elbow extension on their dominant arm.

• Over 50% of pro pitchers develop chronic elbow flexion contractures.

• These changes stem from repetitive stress and tightness in the biceps, brachialis, and forearm muscles.

• Even small changes in elbow extension can change ball release, arm path, and impact shoulder kinematics.

  
  

⚠️ Overall Implications for Baseball and Softball Players

1. Immediate and Long-Term Adaptations

• Even one 40–50 pitch bullpen can reduce internal rotation by 10° and elbow extension by 3°.

• Without intervention, these small changes accumulate across a season, leading to chronic motion loss.

2. Performance Impact

• Reduced ROM disrupts the kinetic chain, limiting velocity and control.

• Compensations increase stress on the low back, elbow, and wrist.

3. Injury Risk

• Every degree of motion lost increases risk for shoulder or elbow injury.

• Increased valgus stress on the elbow contributes to UCL tears and overuse conditions.

🧩 Recommendations for Prevention and Management

🔹 Range of Motion Assessments

• Get regular mobility screens by a physical therapist or athletic trainer.

• Track changes in shoulder IR, ER, flexion, and elbow extension throughout the season.

🔹 Mobility and Flexibility Training

• Focus on cross-body and sleeper stretches, foam rolling, and thoracic spine mobility.

• Use manual therapy and soft tissue work for the posterior capsule, biceps, and forearm.

🔹 Strength and Stability Work

• Strengthen the rotator cuff and scapular stabilizers.

• Add core stability and triceps strengthening to support proper mechanics.

🔹 Recovery and Maintenance

• Include post-throw recovery routines — light band work, stretching, and soft tissue release.

• Prioritize rest and load management between outings.

🧠 Final Takeaway

Maintaining optimal shoulder and elbow mobility is critical for baseball and softball athletes. Off season is the time to evaluate your mobility and address your deficits. Consistent attention to flexibility, thoracic mobility, and scapular control helps maximize performance and minimize injury risk throughout your career.

📍Need Help?

If you’re noticing decreased shoulder motion, elbow tightness, or soreness after throwing, it’s time for a professional mobility assessment.

Contact Athletic Edge and Wellness in Algonquin, IL📞 224-505-3343. We’ll help you build a customized off-season shoulder mobility and strength program designed for your baseball and softball athlete.

Athletic Edge and Wellness, Illinois Baseball Edge, and 1Top Prospect in Algonquin IL are your professional throwing partners in elite baseball/softball performance and arm care through the continuum of ages and competition levels.  We offer team and hyper-personalized private instruction to help players move better, maximize training progressions, and more efficiently navigate the college recruitment process.  Our services include player centric training on elements such as velocity, command, secondary pitch, arm care, recovery (including Normatec), physical therapy, performance therapy, strength and mobility, and consulting that provides personal attention to student-athletes on their collegiate recruiting journey.  These services are offered under one roof.  Come experience the difference with a professional staff that is world class, tightly aligned, and able to collaborate for superior results.