Effects of Whole-body Electrical Muscle Stimulation Exercise on Adults With Myasthenia Gravis

Inclusion Criteria for Participants with MG:

• Age 18 or older

• Diagnosed with Generalized Myasthenia Gravis (gMG) via seropositive test for acetylcholine receptor (AChR) antibodies or seronegative test with clinical symptoms consistent with gMG

• On stable MG therapy for at least 1 month

• Ability to stand for approximately 15 minutes continuously with or without an assistive device (i.e. the length of time to stand to take a shower, complete meal preparation, wait in line at the bank, etc.)

• Score of 1 (Mild) or 2 (Moderate) on at least one side of the "arm outstretched" and "leg outstretched" items of the QMG, demonstrating fatigability

• At least some anti-gravity strength in major muscle groups as assessed by manual muscle testing (i.e. 2+/5 strength or better)

• Medical clearance to participate in an exercise program

• Ability to provide informed consent

• Ability to conform to the requirements of the study (i.e. attendance at assessment and intervention visits, maintain current level of non-study physical activity for the duration of the study, no intention to relocate mid-study)

Exclusion Criteria for Participants with MG:

• Concurrent participation in another interventional research study

• Unable to tolerate 15 minutes of continuous standing with or without an assistive device

• Regular participation in strength training (2x per week or more over the past 6 months)

• Score of 0 (None) on all "arm outstretched" and "leg outstretched" items of the QMG

• Presence of a pacemaker, metal implants, or other implanted medical devices that could impact participant safety during WB-EMS intervention

• Presence of unstable acute or chronic disease (i.e. renal failure, rheumatologic disease, cardia arrhythmia, neoplasm, uncontrolled hypertension)

• Known pregnancy at time of screening

• Presence of a terminal disease (i.e. receiving hospice services)

• Current or previous use of any drugs known to influence muscle mass or performance within 6 months; these may include but are not limited to anabolic steroids, IGF01, growth hormone, replacement androgen therapy, anti-androgen therapy

• Presence of an additional neuromuscular or neurologic condition affecting somatosensory or motor function/control (i.e. motor neuron disease, muscle disease, peripheral neuropathy, other NMJ condition, Parkinson's disease, Multiple Sclerosis, h/o stroke, traumatic brain injury, spinal cord injury, ataxia, apraxia, hemiplegia, etc.)

• Musculoskeletal condition or surgery in the past year that would confound results of exercise interventions (i.e. knee replacement, hip replacement, rotator cuff repair, spinal fusion)

• Other medical conditions, signs, or symptoms that would interfere with study conduct or interpretation of results as determined by an investigator

Inclusion Criteria for Healthy Controls:

• Age 18-39 years

• Ability to provide informed consent

Exclusion Criteria for Healthy Controls:

• Concurrent participation in an interventional research study

• Presence of unstable acute or chronic disease (i.e. renal failure, rheumatologic disease, cardia arrhythmia, neoplasm, uncontrolled hypertension)

• Presence of a terminal disease (i.e. receiving hospice services)

• Current or previous use of any drugs known to influence muscle mass or performance within 6 months; these may include but are not limited to anabolic steroids, IGF01, growth hormone, replacement androgen therapy, anti-androgen therapy

• Presence of an additional neuromuscular or neurologic condition affecting somatosensory or motor function/control (i.e. motor neuron disease, muscle disease, peripheral neuropathy, other NMJ condition, Parkinson's disease, Multiple Sclerosis, h/o stroke, TBI, SCI, ataxia, apraxia, hemiplegia, etc.)

• Musculoskeletal condition or surgery in the past year that would confound results of exercise interventions (i.e. TKA, THA, RTC repair, spinal fusion)

• Other medical conditions, signs, or symptoms that would interfere with study conduct or interpretation of results as determined by an investigator

Healthy controls will complete dEMG testing only during a one-time session.