Myasthenic Syndrome Exercise Protocol

Myasthenic syndromes overview and exercise considerations: 1) Disease characteristics - myasthenia gravis (MG, autoimmune neuromuscular junction disorder, fluctuating muscle weakness with use), Lambert-Eaton myasthenic syndrome (LEMS, voltage-gated calcium channel autoimmunity, often paraneoplastic with small cell lung cancer, weakness with improvement after brief use - facilitation), congenital myasthenic syndromes (CMS, genetic NMJ disorders); 2) Exercise pathophysiology in MG - reduced safety factor at neuromuscular junction; with repeated activity, EPP (end-plate potential) becomes subthreshold; weakness emerges; rest restores transmission; 3) LEMS - opposite pattern with post-tetanic facilitation; brief intense activity actually transiently improves strength; 4) Disease activity considerations - stable mild MG: moderate exercise generally safe with monitoring; recent exacerbation: rest and gradual return; bulbar MG: respiratory muscle training crucial; ocular MG: exercise generally safe; pre-thymectomy: optimize for surgery; 5) Medication interactions - anticholinesterase timing (peak effect 1-2 hours post pyridostigmine - exercise during this window); corticosteroid effects (myopathy with long-term use, osteoporosis - exercise is bone-protective); immunosuppressants stable; 6) Specific contraindications/cautions - active infection, uncontrolled crisis, fever, recent thymectomy <2 months, unstable medications, severe weakness MGFA class IV-V; 7) Pre-exercise assessment - MGFA classification, QMG score, MG-ADL, fatigue scales (FSS, MFI), pulmonary function (FVC, MIP/MEP), 6-minute walk test, manual muscle testing, balance assessment.

Aerobic and respiratory training: 1) Aerobic exercise - moderate intensity 30-50% VO2max (heart rate reserve method) or 11-13 RPE scale; mode: cycling preferred over walking (less fall risk, controlled effort), swimming/aquatic excellent (buoyancy reduces work, cooling, low joint stress, but careful with breath holds), recumbent options for fall risk; duration starts at 10-15 minutes, progressed to 30-40 minutes; frequency 3-5 days/week; 2) Aerobic protocol example - week 1-2: 10-15 min cycling 3 days/week at 11 RPE; week 3-4: 20-25 min 3-4 days/week 12 RPE; weeks 5-12: 30 min 4-5 days/week 13 RPE; long-term: maintenance 3-5 days/week; 3) Respiratory muscle training - critical for bulbar/respiratory MG; inspiratory muscle trainer (Threshold IMT, Powerbreathe), 30% MIP intensity, 30 breaths twice daily, progressing to 60% MIP; for severely affected MIP <30 cmH2O - hospital-supervised; 4) Cooling considerations - heat sensitivity (Uhthoff-like phenomenon) common; cool environment, evaporative cooling, ice towels, scheduled in cool morning hours; aquatic exercise in cool water beneficial; 5) Monitoring - symptoms during/after exercise (specific MG fatigue vs general fatigue), pyridostigmine timing, skin temperature, RPE, target heart rate; stop if pronounced muscle fatigue beyond expected, dyspnea worsening, ptosis worsening, dysphagia; 6) Special populations - LEMS exercise tolerated better with patient learning to use facilitation, repetitive bursts may be helpful; CMS variable based on subtype; MuSK MG - particular focus on bulbar/respiratory; ocular MG - mostly straightforward exercise.

Resistance and functional training: 1) Resistance training principles - low intensity 30-50% 1RM, multiple sets 2-3 with 8-12 reps, slow progression; focus on functional tasks; avoid eccentric exercise (can cause excessive fatigue); avoid prolonged isometric holds; 2-3 days/week with 48-72 hours rest between same muscle groups; 2) Programming - large muscle groups first when fresh, smaller after; bilateral or unilateral as tolerated; functional movements (sit-to-stand, step-ups) preferred to isolation; bodyweight exercises modified for strength; 3) Specific exercises by region - lower extremity: chair squats, mini squats, step-ups, wall slides; bridges; standing heel raises (calf weakness common); seated leg extensions/flexions if standing limited; upper extremity: shoulder elevation modifications (scaption preferred), elbow flexion/extension, light dumbbells; trunk: bridges, bird-dog, supine leg lifts; 4) Balance and falls prevention - falls common (40-60% of MG patients), often from leg fatigue; balance training: tandem stance, single-leg stance, dynamic gait drills; integrated with cognitive (dual-task), Tai chi adapted, vestibular component if relevant; assistive devices as needed; home safety modifications; 5) Functional training - activities of daily living simulation, sit-to-stand power, stairs (if able), reaching tasks, fine motor (especially with hand involvement); 6) Long-term maintenance - lifelong commitment for benefit; periodic reassessment by PT; integration into daily life; family/caregiver education; coordinated care with neurologist; 7) Outcomes evidence - randomized trials show improvements in QMG score, MG-ADL, 6MWT, fatigue, depression scores, quality of life without exacerbation; supervised programs more beneficial than home programs; aquatic exercise particularly well-tolerated; 8) Specific patient education - recognize fatigue vs weakness distinction, plan exercise during best symptom hours, hydration, skin temperature, seek help for new ptosis/dysphagia/dyspnea, never push through severe fatigue, communicate with team about response, gradual return after illness; 9) Multidisciplinary care - neurologist (medications, exacerbations), physiatrist (exercise prescription), physical therapist (supervised exercise), occupational therapist (ADL), respiratory therapist if bulbar/respiratory, pulmonologist if FVC <50%, social worker; 10) Future directions - wearable monitoring during exercise, heart rate variability and physiologic monitoring, telerehabilitation for home programs, virtual reality balance training, individualized AI-guided exercise prescription.