NMES to Improve Hip Abductor Strength and Balance

Falls are a leading cause of disability in older adults. Decreased lower extremity muscle mass and strength contribute to balance and mobility limitations. Our more recent work also suggests that in addition to the traditional targets of muscle mass of the thigh and leg muscles, dysfunction of the hip abductors may contribute to balance and mobility limitations resulting in increased fall risk. Older adults with impaired hip abductor muscles demonstrate increased amounts of intramuscular fat (IMAT) in and around the muscles, decreased hip abductor strength, lower balance scores, increased gait variability (a predictor of future falls), and poor stepping mechanics when recovering from a balance perturbation. Increased IMAT and muscle dysfunction of the hip abductors may contribute to poor hip abductor muscle recruitment and make changing these muscle during a traditional intervention difficult. Neuromuscular electrical stimulation (NMES) is one method to improve muscle mass, strength and quality in older adults, but has not traditionally been used on the hip abductors. We propose that a targeted multimodality balance intervention (MMBI) focused on the lateral and diagonal stepping and hip abductor strengthening when combined with NMES will result in improvements in mobility and balance.

Inclusion criteria

Mobility and balance limitations as demonstrated by a self-reported fall within the past year or requiring greater than 8 seconds to complete the 4-square step test

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Exclusion criteria

• Cardiovascular Risks: Poorly controlled hypertension (>160/100); or patient report of: symptomatic angina at rest or during exercise, syncope without known resolution of cause, or a significant coronary event (such as a MI) in the past six months
• COPD requiring home oxygen
• Contraindications to resistance training, including a self-reported history of intracranial or retinal bleeding in the last year or Diabetes with active proliferative retinopathy
• Patient report of significant spinal stenosis that would limit participation in the exercise intervention
• Non-ambulatory mobility status or a transtibial or transfemoral amputation
• Dementia (on medical record review or mini-mental status exam score <24).
• Other severe medical illness or condition that would preclude safe participation in the study as determined by the study team