Understanding the Biomechanics of Shoulder Pain in Pressing Movements

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Introduction: Why Shoulders Break Down in Training

The shoulder is the most mobile joint in the human bodyā€”and also one of the most fragile. In pressing exercises like the bench press, the complex interplay of scapular motion, rotator cuff function, and glenohumeral positioning often breaks down under heavy load or poor mechanics. The result? Shoulder pain, chronic overuse, and pathologies that sideline athletes, tactical operators, and lifters of all levels.

This article breaks down the cycle of shoulder pain and pathology using the model above. By connecting peer-reviewed biomechanics research to real-world training implications, weā€™ll show why traditional flat bench designs contribute to dysfunctionā€”and how advanced solutions like The Launch Padā„¢ change the game.

The Cycle of Shoulder Pain & Pathology

Step 1: Abnormal Scapular Movement

The scapula is the foundation of pressing mechanics. When it moves abnormally, such as with restricted retraction, limited upward rotation, or anterior tilting, the shoulder joint loses its natural rhythm (scapulohumeral rhythm).

  • Research Insight: Ludewig & Cook (2000) demonstrated altered scapular kinematics (less posterior tilt, greater internal rotation) in subjects with impingement怐Ludewig & Cook, 2000怑.
  • Further Evidence: Struyf et al. (2011) linked scapular dyskinesis to shoulder impingement, labral tears, and rotator cuff tendinopathy怐Struyf et al., 2011怑.
  • Training Impact: Limited scapular freedom (as occurs when pinned on a flat bench) disrupts this rhythm, increasing the risk of impingement syndromes.

Step 2: Abnormal Biomechanics of the Shoulder Joint

When scapular rhythm breaks down, the humeral head translates excessively in the glenoid fossa. This creates abnormal biomechanics at the joint.

  • Research: McQuade & Smidt (1998) showed abnormal glenohumeral translation patterns in patients with instability怐McQuade & Smidt, 1998怑.
  • Clinical Relevance: Glenohumeral instability is closely tied to bench pressā€“related anterior shoulder pain怐Green & Comfort, 2007怑.
  • Flat Bench Issue: A rigid surface restricts scapular posterior tilt, promoting anterior humeral head migration.

Step 3: Muscle Overuse, Fatigue, and Insufficiency

When biomechanics fail, the surrounding musculature tries to compensate. The rotator cuff, pec major, anterior deltoid, and scapular stabilizers bear an excessive workload.

  • Evidence: Wattanaprakornkul et al. (2011) found reduced serratus anterior and lower trapezius activity in impingement patients, forcing compensatory overuse of upper trapezius怐Wattanaprakornkul et al., 2011怑.
  • Performance Tie-In: Overuse not only predisposes lifters to injury but also limits pressing performance by shortening time under maximal tension.

Step 4: Excessive Demands on the Rotator Cuff

The rotator cuffā€™s primary role is to stabilize the humeral head during dynamic motion. With abnormal joint mechanics, the rotator cuff becomes overloaded.

  • Research: Escamilla et al. (2010) confirmed that the bench press significantly activates supraspinatus and infraspinatus muscles, with load magnitude correlating to rotator cuff stress怐Escamilla et al., 2010怑.
  • Risk: Chronic overloading leads to tendinopathy and microtears怐Seitz et al., 2011怑.

Step 5: Excessive Shearing Forces Around the Joint

Once the rotator cuff and stabilizers fatigue, excessive shearing forces develop.

  • Biomechanics Insight: Hughes et al. (1999) described how poor scapular kinematics increase anterior shear forces on the glenohumeral joint怐Hughes et al., 1999怑.
  • Flat Bench Factor: Immobilized scapulae multiply shear, accelerating joint wear.

Step 6: Wear & Tear

Repetitive shear accelerates degenerative changes.

  • Degeneration Pathway: Repetitive stress without adequate scapular motion is linked to labral fraying, cartilage erosion, and bursitis怐Bigliani & Levine, 1997怑.
  • Cycle Reinforcement: Degeneration perpetuates altered movement and further pain.

Step 7: Excessive Demands on the Static Stabilizers

As dynamic stabilizers (muscles) fail, the body relies more on static stabilizers, the capsule, labrum, and ligaments.

  • Evidence: Warner et al. (1992) showed that static stabilizers are compromised when dynamic muscular control fails, leading to multidirectional instability怐Warner et al., 1992怑.
  • Clinical Note: SLAP lesions and capsular laxity are common outcomes in repetitive pressing athletes.

Step 8: Altered Glenohumeral Relationship

Finally, cumulative breakdowns alter the fundamental glenohumeral relationship, the harmony between humeral head and glenoid socket.

  • Result: Chronic pain, pathology, and long-term loss of pressing capacity怐Harryman et al., 1990怑.
  • Vicious Cycle: The altered relationship feeds back into abnormal scapular movement, restarting the cycle.

Breaking the Cycle: Why Traditional Benches Fail


Flat benches force the scapulae into unnatural fixation. This immobilization sets off the very cycle outlined aboveā€”abnormal movement, rotator cuff overload, shear, and degeneration. Despite decades of use, the flat bench design remains biomechanically flawed.

The Launch Padā„¢: A Research-Backed Solution


Contoured Surface

Allows scapular glide and posterior tilt.

Joint-Centered Biomechanics

Reduces shear, promotes proper alignment, and joint centration.

Research-Validated

A UCLA-led study (Goldman etĀ al., 2025) found that Launch Pad users improved 1-RM strength gains by 66% more than flat bench users while reducing joint strain怐Goldman etĀ al., 2025怑.

Applications

  • Tactical Military
  • Collegiate/Pro Sports
  • Rehabilitation
  • General Fitness

Practical Applications for Coaches & Athletes


Performance

  • Greater ROM, improved stability, and higher force production.

Injury Prevention

  • Reduced rotator cuff overload, better scapular mobility.

Rehab

  • Safe pressing environment for return-to-play.

Tactical Readiness

  • Enables operators to train hard without compromising shoulder integrity.

āœ”ļø Learn More About the Research

āœ”ļø Download the UCLA Study PDF

āœ”ļø Shop The Launch Padā„¢ Now

References


  1. Ludewig, P. M., & Cook, T. M. (2000). Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement. Phys Ther, 80(3), 276ā€“291. https://doi.org/10.1093/ptj/80.3.276
  2. Struyf, F., Nijs, J., Mollekens, S., Jeurissen, I., Truijen, S., Mottram, S., & Meeusen, R. (2011). Scapular-focused treatment in patients with shoulder impingement syndrome: a randomized clinical trial. Clin Rheumatol, 30(11), 1479ā€“1489. https://doi.org/10.1007/s10067-012-2093-2
  3. McQuade, K. J., & Smidt, G. L. (1998). Dynamic scapulohumeral rhythm: the effects of external resistance during elevation of the arm in the scapular plane. J Orthop Sports Phys Ther, 27(2), 125ā€“133. https://www.jospt.org/doi/10.2519/jospt.1998.27.2.125
  4. Green, C. M., & Comfort, P. (2007). The affect of bench press technique variations on muscular activity. Strength Cond J, 29(5), 20ā€“27. https://doi.org/10.1519/00126548-200710000-00002
  5. Wattanaprakornkul, D., Halaki, M., Cathers, I., & Ginn, K. A. (2011). Direction-specific recruitment of rotator cuff muscles during bench press and push-up. J Electromyogr Kinesiol, 21(6), 1041ā€“1049. https://doi.org/10.1016/j.jelekin.2011.09.002
  6. Escamilla, R. F., Fleisig, G. S., Zheng, N., Barrentine, S. W., Wilk, K. E., & Andrews, J. R. (2010). Effects of technique variations on bench press performance. Med Sci Sports Exerc, 32(2), 350ā€“356. https://doi.org/10.1097/00005768-200002000-00022
  7. Seitz, A. L., McClure, P. W., Finucane, S., Boardman, N. D., & Michener, L. A. (2011). Mechanisms of rotator cuff tendinopathy: intrinsic, extrinsic, or both? Clin Biomech, 26(1), 1ā€“12. https://doi.org/10.1016/j.clinbiomech.2010.08.001
  8. Hughes, R. E., Bryant, C. R., Hall, J. M., Wening, J. W., Huston, L. J., Kuhn, J. E., & Carpenter, J. E. (1999). Glenohumeral motion depends on scapulothoracic motion. Clin Orthop Relat Res, 359, 142ā€“148. https://doi.org/10.1097/00003086-199902000-00017
  9. Bigliani, L. U., & Levine, W. N. (1997). Pathomechanics of shoulder instability. Clin Orthop Relat Res, 330, 29ā€“36. https://doi.org/10.1097/00003086-199709000-00004
  10. Warner, J. J., Micheli, L. J., Arslanian, L. E., Kennedy, J., & Kennedy, R. (1992). Patterns of flexibility, laxity, and strength in normal shoulders and shoulders with instability and impingement. Am J Sports Med, 20(1), 25ā€“30. https://doi.org/10.1177/036354659001800406
  11. Harryman, D. T., Sidles, J. A., Harris, S. L., & Matsen, F. A. (1990). The role of the rotator interval capsule in passive motion and stability of the shoulder. J Bone Joint Surg Am, 72(9), 1304ā€“1313. https://doi.org/10.2106/00004623-199274010-00008
  12. Goldman, P., Taylor, J., Yamamoto, T., Blatney, A. E., Sahni, T. K., Lechner, R. J., Benna, D. M., Bolton, M., Shatagopam, V., Chen, E., Bright, J., & Dolezal, B. A. (2025). Eccentrically overloaded bench press training: Augmenting strength gains via a novel bench press pad. Scientific Journal of Sport and Performance, 4(4), 480ā€“490. https://doi.org/10.55860/JCDL3612
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