Swimmer's Rotator Cuff (SITS) Strength Training Program

Introduction

The rotator cuff (abbreviated as SITS, comprising the Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis) is the core of dynamic shoulder joint stability. During swimming, each stroke requires the shoulder joint to perform large ranges of internal and external rotation. If the rotator cuff muscles lack strength or are imbalanced, “swimmer’s shoulder” (shoulder impingement syndrome) is almost an inevitable injury.

It is estimated that 40–70% of competitive swimmers have experienced shoulder pain at some point, with the majority related to rotator cuff dysfunction.

Common Imbalance Patterns

Swimming heavily recruits the internal rotators (subscapularis, pectoralis major, latissimus dorsi), while the external rotators (infraspinatus, teres minor) are relatively neglected. Over time, the shoulder joint develops an “internal rotation dominance,” causing the humeral head to shift anteriorly within the glenoid fossa, reducing the subacromial space and leading to impingement.

Additionally, the supraspinatus is responsible for the initial 30 degrees of arm abduction, acting as the “igniter” for all stroke movements. When the supraspinatus is weak, the body recruits other compensatory muscles, eventually creating movement faults.

SITS Training Program

The following program is designed to be performed 3 times per week, either as activation warm-up before main training or as a standalone session.

Exercise Descriptions

Prone Y/T/W: Lie prone on a bench or the floor, positioning the arms into Y (diagonal elevation), T (horizontal abduction), and W (elbow-flexed external rotation) shapes, emphasizing coordination between the lower trapezius and rotator cuff. This is one of the most recommended preventive exercises for swimmers’ shoulders.

Band External Rotation (90° Abduction Position): Raise the arm to shoulder height and slowly rotate from an internally rotated position to an externally rotated position, simulating the joint motion of the early pull phase. This has the highest training specificity for the infraspinatus.

Eccentric External Rotation: Perform the concentric (external rotation) phase at normal speed, then deliberately slow the eccentric (return to internal rotation) phase to 4–5 seconds. Eccentric training has significant effects on tendon regeneration and repair, making it the preferred strategy for post-injury recovery.

Training Timing and Precautions

• During warm-up: Light SITS training (2–3 sets) can be incorporated into the shoulder warm-up to activate the rotator cuff before large muscle group training or pool work.
• Standalone training day: If you have a history of shoulder injury, it is recommended to schedule a dedicated 20–30 minute SITS session, separate from large muscle group training.
• Avoid the painful arc: If pain occurs at specific angles during movement (especially 60–120° of abduction), stop immediately and consult a physical therapist.

Practical Recommendations

• The external rotation to internal rotation strength ratio (ER/IR ratio) should be maintained above 0.65; if external rotation is significantly weaker than internal rotation, increase external rotation training volume.
• When using resistance bands, the resistance direction should align with the muscle fiber orientation to achieve optimal training effects.
• Assess single-arm support stability monthly (e.g., side plank on the hand), observing for scapular winging, which is a sign of serratus anterior weakness.

Conclusion

Rotator cuff training is tedious but non-negotiable. Many Taiwanese swimmers only pay attention to it after shoulder pain appears, often missing the window for prevention. Incorporating the SITS program into your weekly routine is the lowest-cost, highest-return investment in sports injury prevention.

Related Reading

• Shoulder Strengthening for Swimming: Preventive Rotator Cuff Training
• The Complete Guide to Preventing Swimmer’s Shoulder: Causes, Diagnosis, and Strength Training for Rotator Cuff Injuries
• The Complete Diagnosis and Treatment Guide for Swimmer’s Shoulder
• Shoulder Stability Training for Swimming: Key Movements to Prevent Rotator Cuff Injuries