Injury Is More Than Tissue Damage

Tissue recovery and movement recovery answer different questions

Track four parts of recovery: tissue integrity, physical capacity, movement control and sustained participation.

Strength and tolerance can lag behind tissue repair

Shin and colleagues followed 164 patients after intact arthroscopic rotator cuff repair, measuring isometric forward-flexion, internal-rotation and external-rotation strength before surgery and at 6, 12, 18 and 24 months. Strength recovered more slowly than pain relief and shoulder-function outcomes. Small-tear groups reached contralateral strength in all three directions by six months; medium-tear groups did so by eighteen months. Large-to-massive tears improved but did not reach the opposite shoulder’s strength at final follow-up. [1]

Assess maximal strength and repeated-load tolerance separately. Pressing also requires consistent execution across repetitions and recovery between sessions.

Wall and colleagues immobilized one leg in 24 healthy young men for five or fourteen days, with twelve per group. Quadriceps cross-sectional area fell 3.5% and 8.4%; strength fell 9.0% and 22.9%, respectively.[2]

Weakness can involve muscle size and quality, restricted movement, discomfort and incomplete voluntary activation. Assess the contributors relevant to the individual’s care.

Joint input can change voluntary muscle activation

Arthrogenic muscle inhibition, usually shortened to AMI, describes difficulty fully activating a muscle associated with an affected joint. Rice and McNair’s review explains how changed joint-afferent input can influence spinal and supraspinal motor pathways after injury, surgery or joint disease. The most developed experimental literature concerns the quadriceps and knee. AMI is a neurophysiological phenomenon, not a judgment about effort or willingness. [3]

Palmieri-Smith and colleagues isolated two possible contributors in a randomized-order crossover study of fourteen healthy adults: a normal knee, experimentally induced effusion, experimentally induced pain, and both together. Sessions were separated by five to seven days. They measured knee-extension torque and used an electrical burst during maximal effort to estimate voluntary activation. Each experimental condition reduced both outcomes relative to the normal condition; differences between the three experimental conditions were not statistically significant. [4]

The central activation ratio estimates voluntary activation from the force response to an added electrical burst during maximal effort.

Rice and colleagues provide a useful counterexample to a simple “cortex switches off” explanation. In seventeen healthy volunteers, they infused a knee to a standardized pressure and used transcranial magnetic stimulation, or TMS. Motor-evoked-potential area increased after infusion, at rest and during contraction; cortical silent-period duration decreased. Short-interval intracortical inhibition and facilitation did not change significantly. Twelve participants reported no pain and the others rated it at most 5/100. [5]

Joint swelling changed the stimulated pathway’s excitability. Interpret this alongside voluntary torque and activation measures to understand motor function.[5]

Recovery includes the information used to control movement

Proprioception is the sense of body position, movement and force. Proske and Gandevia’s physiological review describes contributions from muscle, skin and joint receptors, interpreted alongside signals related to motor commands. It is not a single sensor inside a ligament, and it is not synonymous with balance. Different tasks can emphasize different information. [6]

Pressing requires the athlete to sense upper-arm and torso position, direct hand force and maintain useful bench contact. Assess available range and active control through that range.

Anatomical context · sensory feedback

The shoulder is both a moving structure and a source of information

Available movement

The positions the joint and surrounding tissues permit.

Sensory information

Signals from muscle, skin and joint contribute to the sense of position and movement.

Active control

The athlete organizes force and motion using sensory information alongside motor commands.

What a sensory test measures

Ager and colleagues reviewed twenty-one shoulder-proprioception studies with 407 participants. Position-matching and movement-detection protocols varied; only two assessed validity, and none reported responsiveness. Choose a test suited to the sensory function being followed.[7]

A change in discrimination after repair

In an uncontrolled pre–post study, Cao and colleagues tested thirty-one patients with unilateral partial-thickness cuff injuries before repair and one week afterward. Active external-rotation discrimination improved on the affected side and no longer differed significantly from the opposite shoulder.[8]

Follow sensory performance over time and connect it to the movement being resumed. For pressing, pair the sensory assessment with a familiar, reproducible task.

The central nervous system can adapt after injury

Brain activity during a knee movement

Grooms and colleagues compared fifteen people after left anterior cruciate ligament reconstruction with fifteen matched controls. At an average 38.13 months after surgery, participants repeatedly flexed and extended the knee during functional MRI. The reconstructed group showed a different distribution of brain activity, including greater activation in the contralateral motor cortex and lingual gyrus and lower activation in the ipsilateral motor cortex and cerebellum. The authors proposed greater reliance on a visual-motor strategy. [9]

This controlled laboratory comparison establishes a group difference during the tested movement. It does not establish each participant’s preinjury brain state, prove that the difference caused disability, or reveal what happens during a heavy bench press. Functional MRI measures a blood-oxygenation-related signal; it does not directly count motor-unit impulses. The study is valuable because it expands the recovery question beyond the reconstructed ligament while leaving the interpretation attached to its method.

Motor excitability in a painful shoulder

There is also shoulder-specific evidence. Ngomo and colleagues used TMS to examine infraspinatus representation in thirty-nine patients with unilateral rotator cuff tendinopathy. Active motor threshold was higher on the affected side, consistent with lower corticospinal excitability. The asymmetry correlated with pain duration (r = .45; p = .005), but not pain intensity. In a subset of sixteen, cortical map location and motor-response amplitude across stimulation intensities did not differ significantly between sides. [10]

In this cross-sectional tendinopathy sample, active motor threshold differed between shoulders, while map location and response amplitude did not. Assess these measures alongside symptoms and function.[10]

Connect the neural finding to function

Knee and shoulder studies identify central motor changes that may accompany injury. Their practical relevance lies in how they relate to the individual’s function, symptoms and recovery.

Shoulder function and movement can recover differently

Baumgarten and colleagues retrospectively analyzed prospectively collected outcomes from forty-eight patients undergoing rehabilitation after arthroscopic rotator cuff repair. They followed scapular substitution, patient-reported outcomes, active motion and strength for up to twelve months. Therapist-observed substitution decreased from 82% to 35% through the first postoperative year. Patients with substitution tended to have poorer outcomes, range and scaption strength. [11]

Follow changes in scapular movement alongside strength, stiffness and function to understand the athlete’s recovery.

Mercurio and colleagues added a prospective assessment of twenty-one patients before cuff repair and at a minimum twelve-month follow-up, using magnetic-inertial sensors to characterize three-dimensional scapular motion during arm elevation. Active motion and clinical scores improved, while most comparisons of scapulohumeral rhythm did not show a statistically significant pre–post difference. The paper describes persistent dyskinesis despite broader clinical improvement. [12]

Assess the shoulder girdle as a coordinated system. Reassess persistent movement changes when they accompany weakness, limited function or difficulty sustaining the intended task.

Returning to pressing adds torso support, a coupled-hand barbell task and repeated-set demands. The return-after-repair and scapular-motion articles connect these requirements to shoulder assessment.

Pain is real, and its relationship with tissue state is not one-to-one

Nociception is neural processing of potentially tissue-damaging stimulation. Pain is a personal, unpleasant sensory and emotional experience influenced by biological, psychological and social factors. Nociceptive activity does not by itself establish the presence or intensity of pain.[13]

Interpret pain alongside tissue status, strength, movement and training response. Several contributors can interact during recovery.

How sensitivity can change

Woolf describes central sensitization as increased responsiveness in central nociceptive pathways. It can amplify pain responses or extend sensitivity beyond the original site. Peripheral sensitization increases nociceptor responsiveness near the tissue; both processes can interact.[14]

Pressure-pain thresholds record the response to a controlled stimulus. Interpret sensory tests and questionnaires as part of the clinical assessment.

What the shoulder study found

King, Shapiro and Karduna compared twenty people with unilateral subacromial pain syndrome with twenty matched controls. Pressure-pain thresholds were lower at the affected shoulder, but remote-site group differences were not significant overall. Sex-stratified findings suggested more widespread sensitivity among the ten female patients. After a pain-reducing injection, clinical pain fell, but pressure sensitivity did not change significantly in the short observation period. [15]

The study found different patterns of shoulder sensitivity across participants and a distinction between immediate pain relief and pressure sensitivity. Clinical assessment should consider local tissue input, neurological factors and altered nociception together.

Protection can change the strategy while preserving the task

Hodges and Tucker proposed that adaptation to pain often involves redistribution of activity within and between muscles, with changes at multiple levels of the motor system. A protective response may reduce exposure to a threatened region or modify how a task is performed. The response can vary between people and tasks; there is no requirement that every painful muscle become uniformly inactive or every neighboring muscle become more active. [16]

This framework helps explain an apparent paradox: the movement can still be completed while the strategy has changed. Preserving the external outcome may require a different distribution of effort, stiffness or joint motion. A successful repetition can therefore be informative without revealing all the work occurring beneath it. Whether the alternative is useful, neutral or costly depends on what it allows and what demands it creates.

Bank and colleagues reviewed 112 studies of experimentally induced limb pain in healthy people. Pain changed motor processing and muscle activity while many task outcomes remained intact and visible movement changes were often subtle.[17]

Reassess guarded movement as symptoms and capacity change. Remaining weakness, stiffness, unfamiliarity and protective behavior may each contribute.

When Compensation Becomes the Strategy examines how repeated movement solutions develop and when they deserve reassessment.

Assess physical capacity, pain processing and context

Assess range, force capacity, tissue status and sustainable training exposure alongside sensory and motor control.

Expectations can influence pain experience

With drug concentration and heat stimulation held constant, Bingel and colleagues found that positive expectations increased remifentanil’s analgesic benefit and negative expectations eliminated the observed benefit in healthy volunteers.[18]

Confidence and uncertainty may affect participation after injury. Consider the athlete’s account alongside examination findings and responses to activity.

Take the athlete’s pain seriously and investigate it alongside tissue findings, capacity and the demands of the task.

Consider the effect of reduced activity

Reduced activity can make a previously routine workload more demanding. Reassess what the athlete can do, how the movement is performed and the response afterward.

The return task has to be defined before recovery can be judged

The 2025 American Academy of Orthopaedic Surgeons guideline reports better functional and patient-reported outcomes after healed cuff repairs than unhealed repairs. Preserve repair-specific restrictions and let the treating clinician guide the individual progression.[19]

Define the return task through grip, range, implement, torso support, speed and fatigue. Pair task-specific performance with the clinician’s assessment of repair integrity and physical capacity.

Follow tissue status, strength, range, relevant sensory or activation measures, a reproducible pressing task, and symptoms and participation over time.

Equipment affects contact, available movement and the setup the athlete must control. Include the support surface when recording a return-to-pressing task.

A related question concerns the practice environment. The Equipment Is Part of the Motor-Learning Environment considers how the physical setup may shape practice. Here, the evidence establishes why that question matters after injury: the athlete is returning with a history of altered tissue, exposure, sensation and behavior. A useful outcome is the recovery of meaningful, sustainable function, assessed with measures that can actually describe it.

For an injury or postoperative return, the treating clinician sets the progression and restrictions.