The Shoulder Dysfunction & Load-Intolerance Cycle: A Proposed Framework for Repetitive Pressing

Shoulder trouble during pressing rarely behaves like a single broken link. This eight-stage model organizes how task mechanics, fatigue, motor responses, symptoms and exposure may reinforce one another—and where the loop can be interrupted.

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Key Takeaways

A cycle is useful only if it preserves uncertainty and reversibility.

The model organizes eight interacting states that can be observed and tested separately rather than assumed to form one inevitable chain.

Scapular dyskinesis is common in asymptomatic athletes; it is a finding, not a diagnosis.

Fatigue and pain can change movement, but the response may be protective, neutral or costly depending on context.

Modeled joint loading, EMG, bar kinematics, symptoms and injury are different endpoints.

Technique, recovery, load management, clinical care and support conditions can enter at multiple stages.

AMM research changes the surface-mechanics/performance question; it does not validate a pain or injury pathway.

How to read the framework

Eight states, two-way transitions, many entry and exit points

Complex-systems injury models reject the idea that one isolated “risk factor” produces a predictable outcome. They ask how interacting constraints create a pattern over time [1]. This article applies that logic to repetitive pressing, but the cycle is a proposal: it is a map of testable links, not a validated natural history.

That distinction is essential because altered scapular motion is common without pain. Burn and colleagues synthesized 12 studies involving 1,401 athletes and reported dyskinesis in 61% of overhead athletes and 33% of nonoverhead athletes [2]. Hickey and colleagues pooled five prospective cohorts (419 athletes) and found a 43% higher future shoulder-pain risk when dyskinesis was present at baseline (RR 1.43, 95% CI 1.05–1.93) [3]. Prevalence and prospective association can coexist: a common sign may shift risk without identifying cause, diagnosis or destiny. The Scapular Summit consensus likewise treats dyskinesis as an impairment that must be interpreted inside a clinical examination, not as a diagnosis by itself [4].

Dominant visual · proposed eight-stage feedback model

The Shoulder Dysfunction & Load-Intolerance Cycle

Every perimeter connection is bidirectional. Athletes may enter, stabilize or exit at any stage.

Eight-stage shoulder dysfunction and load-intolerance cycleEight numbered boxes form a loop with two-way arrows: task constraints, altered mechanics, local demand, fatigue, movement adaptation, symptom response, reduced tolerance, and repeated exposure. A central box lists technique, load, recovery, clinical care and support conditions; dashed two-way spokes show multiple entry and exit points. 01 · DIRECT / DESCRIPTIVETASK CONSTRAINTSload · grip · range · surface02 · DIRECT / MODELEDALTERED MECHANICSbar path · pose · forces03 · INFERENCELOCAL DEMANDmuscle · joint · tissue04 · DIRECTFATIGUEwithin-set · accumulated05 · DIRECT / VARIABLEMOVEMENT ADAPTSprotective or performance-led06 · ASSOCIATIONSYMPTOM RESPONSEpain · apprehension · recovery07 · PROPOSEDREDUCED TOLERANCEless capacity for the same task08 · EXPOSUREREPEATED PRESSINGdose meets current stateINTERRUPT AT ANY STAGETechniqueLoad managementRecoveryClinical careSupport condition
  1. 01 · Direct/descriptive

    Task constraints: load, grip, range and support.

  2. 02 · Direct/modeled

    Altered mechanics: bar path, pose and external/modelled forces.

  3. 03 · Inference

    Local demand: muscle, joint and tissue requirements.

  4. 04 · Direct

    Fatigue: within-set and accumulated.

  5. 05 · Direct/variable

    Movement adapts: protective, performance-led or costly.

  6. 06 · Association

    Symptom response: pain, apprehension and recovery.

  7. 07 · Proposed

    Reduced tolerance: less capacity for the same task.

  8. 08 · Exposure

    Repeated pressing: dose meets the athlete’s current state.

TechniqueChange execution or range
LoadChange dose or proximity to fatigue
RecoveryChange frequency and restoration
Clinical careAssess, diagnose and treat
SupportChange the physical condition
The evidence labels describe the link type, not a grade for an individual athlete. Arrows show possible influence in both directions, not inevitable progression.
The framework has no mandatory starting point, no irreversible step and no product positioned as a universal exit.

Evidence behind the links

What is measured, what is associated and what remains proposed

01 → 02

Task constraints change mechanics

In experienced lifters, grip width, scapular pose and shoulder-abduction targets changed modeled glenohumeral and acromioclavicular forces [5]. Lateral barbell forces also materially affect calculated net joint moments [6].

Direct mechanics + modeling · not symptoms
02 ↔ 03

Mechanics inform demand, with model limits

Motion and external force help estimate muscle and joint demand, but the estimates depend on anatomical and optimization assumptions. A lower modeled component is not proof of lower tissue damage or clinical risk.

Mechanistic inference
03 ↔ 04

Demand and fatigue interact

Duffey and Challis tracked ten men during sets to fatigue and found systematic changes in bar kinematics as repetitions accumulated [7]. A 2024 narrative review integrates fatigue and shoulder-biomechanics hypotheses, but it does not provide a prospective injury threshold [8].

Direct kinematics · narrative risk synthesis
03 → 05

Recruitment is direction-specific

Wattanaprakornkul and colleagues used EMG to show direction-specific rotator-cuff recruitment during bench press and row [9]. Recruitment describes a motor strategy; it does not identify a damaged structure.

Direct EMG · no injury endpoint
04 ↔ 05

Movement can adapt without “failure”

A slower or altered bar path may preserve performance, redistribute load or signal that the rep has left its intended standard. The direction is athlete- and task-dependent; the model should record the adaptation before assigning it a value.

Direct observation · interpretation required
05 ↔ 06

Pain changes movement variably

Hodges and Tucker propose that pain alters motor behavior by redistributing activity within and between muscles. The response can protect a threatened region in the short term while creating other costs if it persists [10].

General pain theory · not bench-specific
06 ↔ 07

Symptoms and tolerance are not interchangeable

Pain can reduce willingness or ability to repeat a task, while low tolerance can raise the chance that a dose provokes symptoms. Neither proves structural damage. Clinical examination is the appropriate route when symptoms persist, recur or follow trauma.

Proposed state transition
07 ↔ 08

Exposure meets the athlete’s current state

The same session can be tolerable in one state and excessive in another. Injury-surveillance reviews describe where problems are reported in strength sports, but heterogeneous methods cannot supply this model’s transition probabilities [11].

Exposure logic · no causal sequence

Practical use

Intervene at the earliest observable link—then verify the response

The model is not a checklist for locating one root cause. It is a measurement plan: identify the state that can be observed, change one defensible input and watch both the intended outcome and downstream response.

Before symptoms

Standardize. Record grip, range, contacts, support, load and fatigue endpoint. Use video or velocity only if the measurement changes a decision.

Technique drifts

Decide what it means. A changed bar path may be an acceptable solution or an invalid repetition. Apply the rule specified before the set.

Recovery worsens

Adjust exposure. Reduce dose, proximity to failure, range or frequency; then observe whether tolerance returns rather than assuming one mechanical cause.

Symptoms persist

Escalate appropriately. Clinical assessment can identify diagnoses, red flags and individualized constraints that this training framework cannot.

The relationship is bidirectional. Better capacity can expand tolerable exposure; an appropriate exposure can build capacity. Pain reduction may permit cleaner practice, and cleaner practice may improve confidence. Conversely, rest alone may reduce symptoms without restoring tolerance for the original task.

Where the support interface belongs

A changed surface enters at the task-constraint stage

The Launch Pad studies provide direct evidence that one complete support condition changed acute repetition mechanics/performance and longitudinal performance under specific programs. They do not validate the full cycle or establish a clinical interruption.

Acute crossover · n = 10 resistance-trained men

The surface changed measured repetition outputs

Measured

Right/left pectoralis sEMG, mean/peak velocity, vertical bar displacement and power.

Result and boundary

The Launch Pad condition produced 24.4% and 27.1% higher pectoralis sEMG, 17.5% and 15.8% higher mean/peak velocity and 15.8% greater vertical displacement. Power was 8.8% higher but nonsignificant after correction (p = .071) [12]. No pain or injury outcome was measured.

In a four-week trial of 42 intermediate-trained men, the same supervised eccentric-overload program produced an average 1-RM gain of 18.4 kg (40.6 lb) with the Launch Pad versus 11.1 kg (24.5 lb) conventionally—a 7.3 kg (16.1 lb) difference, about 66% greater average improvement (p < .001) [13]. That is an interface comparison under AEL, not an AEL-versus-conventional-training comparison.

In a separate eight-week trial, 30 collegiate football players completed matched periodized programs for 24 supervised sessions. The Launch Pad group improved more in 1-RM, NFL-225 repetitions and seated medicine-ball throw distance; all reported between-group comparisons were p < .001 [14]. Those are performance outcomes. They do not show that the interface prevented injury, treated pain or changed any specific transition in this cycle.

Joint Ops boundaryJoint Ops is a distinct system in active prototype research with no published outcomes. A cycle study would need to compare defined configurations and measure the proposed mediator and downstream state directly; Launch Pad performance evidence cannot be reassigned to Joint Ops.

Research agenda

Test links in sequence instead of validating the picture by impression

A strong longitudinal design would standardize grip, range, support and load; repeatedly capture three-dimensional motion, vertical and lateral external forces, bar kinematics, muscle activity, symptoms, next-day function and exposure; and define in advance what counts as a meaningful state transition.

What a cycle-validation program would have to demonstrate
QuestionMinimum evidenceNull result that still matters
Does a constraint change mechanics?Randomized, familiarized condition comparison with direct motion and force data.The configuration changes perceived support but not the preregistered mechanical mediator.
Does the mediator change tolerance?Repeated exposure with temporal ordering and symptom/function measures.Mechanics change without a later tolerance difference.
Does an intervention interrupt the loop?Prospective comparison showing the targeted link changes before downstream outcomes.Symptoms improve equally while the proposed mediator remains unchanged.
Does the result generalize?Replication across sexes, body dimensions, training ages and clinical states.A response appears only in one subgroup or configuration.
Established here

Bench constraints can change acute mechanics and performance; fatigue can change bar kinematics; pain-related motor adaptation is variable; a support condition can change acute and longitudinal performance outcomes.

Unresolved here

The direction and strength of most transitions, whether the complete loop occurs in pressing athletes, and whether any equipment configuration changes pain, injury or rehabilitation outcomes.

Continue Reading

Bench-Press Shoulder RiskUse Article 16’s demand–capacity model for risk-factor and surveillance evidence.Scapular Motion During the Bench PressSeparate scapular motions from the shorthand of “retraction.”Shoulder Mechanics & Surface DesignReview bench-specific mechanics without turning models into diagnoses.Velocity Loss, Fatigue & AdaptationTrack how repetition performance changes across a set.

Use the cycle to ask a better next question

Identify the observable link, choose a reversible input and measure whether the intended state actually changed.

Open the Research HubFollow Joint Ops™ Research

Medical notice: This proposed framework is educational and is not a diagnostic or treatment algorithm. Persistent, traumatic, postoperative or neurologic symptoms require individualized evaluation by an appropriately qualified clinician.

References

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  2. Burn MB, McCulloch PC, Lintner DM, Liberman SR, Harris JD. (2016). Prevalence of scapular dyskinesis in overhead and nonoverhead athletes: A systematic review. Orthopaedic Journal of Sports Medicine, 4(2), 2325967115627608. doi:10.1177/2325967115627608. ↩
  3. Hickey D, Solvig V, Cavalheri V, Harrold M, McKenna L. (2018). Scapular dyskinesis increases the risk of future shoulder pain by 43% in asymptomatic athletes: A systematic review and meta-analysis. British Journal of Sports Medicine, 52(2), 102–110. doi:10.1136/bjsports-2017-097559. ↩
  4. Kibler WB, Ludewig PM, McClure PW, Michener LA, Bak K, Sciascia AD. (2013). Clinical implications of scapular dyskinesis in shoulder injury: The 2013 consensus statement from the Scapular Summit. British Journal of Sports Medicine, 47(14), 877–885. doi:10.1136/bjsports-2013-092425. ↩
  5. Noteboom L, Belli I, Hoozemans MJM, Seth A, Veeger HEJ, van der Helm FCT. (2024). Effects of bench press technique variations on musculoskeletal shoulder loads and potential injury risk. Frontiers in Physiology, 15, 1393235. doi:10.3389/fphys.2024.1393235. ↩
  6. Mausehund L, Werkhausen A, Bartsch J, Krosshaug T. (2022). Understanding bench press biomechanics—the necessity of measuring lateral barbell forces. Journal of Strength and Conditioning Research, 36(10), 2685–2695. doi:10.1519/JSC.0000000000003948. ↩
  7. Duffey MJ, Challis JH. (2007). Fatigue effects on bar kinematics during the bench press. Journal of Strength and Conditioning Research, 21(2), 556–560. doi:10.1519/R-19885.1. ↩
  8. Motlagh JG, Lipps DB. (2024). The contribution of muscular fatigue and shoulder biomechanics to shoulder injury incidence during the bench press exercise: A narrative review. Journal of Strength and Conditioning Research, 38(12), 2147–2163. doi:10.1519/JSC.0000000000004973. ↩
  9. Wattanaprakornkul D, Halaki M, Cathers I, Ginn KA. (2011). Direction-specific recruitment of rotator cuff muscles during bench press and row. Journal of Electromyography and Kinesiology, 21(6), 1041–1049. doi:10.1016/j.jelekin.2011.09.002. ↩
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  11. Tung MJY, Lantz GA, Lopes AD, Berglund L. (2024). Injuries in weightlifting and powerlifting: An updated systematic review. BMJ Open Sport & Exercise Medicine, 10(4), e001884. doi:10.1136/bmjsem-2023-001884. ↩
  12. Kidwell JA, Yamamoto T, Hetherton KJ, Truneh N, Bright JJ, Blatney AE, et al. (2026). Acute effects of thoracic-spinal elevation via a novel bench press pad on sEMG and barbell kinetics in resistance-trained males. International Journal of Exercise Science, 19(1), 1003. doi:10.70252/IJES2026103. ↩
  13. Goldman P, Taylor J, Yamamoto T, Blatney AE, Sahni TK, Lechner RJ, et al. (2025). Eccentrically overloaded bench press training: Augmenting strength gains via a novel bench press pad. Scientific Journal of Sport and Performance, 4(4), 480–490. doi:10.55860/JCDL3612. ↩
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