Nishikawa Y1, Watanabe K2, Takahashi T3, Kawade S4, Kimura H5, Maruyama H3, Hyngstrom A6
1Hiroshima University Hospital, Division of Rehabilitation, Department of Clinical Practice and Support, Hiroshima, Japan, 2Chukyo University, Laboratory of Neuromuscular Biomechanics, School of International Liberal Studies, Nagoya, Japan, 3Hiroshima University, Department of Clinical Neuroscience and Therapeutics, Hiroshima, Japan, 4MTG Co., Ltd, Nagoya, Japan, 5Hiroshima University Hospital, Department of Rehabilitation, Hroshima, Japan, 6Marquette University, Department of Physical Therapy, Milwaukee, United States

Background: The Japanese Orthopaedic Association proposed the concept of the locomotive syndrome in 2007, which they defined as a condition of decreased mobility in activities essential to daily life, such as walking, standing, and climbing stairs, resulting from impairments in the musculoskeletal system. Although declines in mobility are often multifactorial, muscle strength is an important factor in the prevention of falls and the progression of orthopedic disorders. Declines in muscle strength in the elderly are due to both decreased ability to volitional activate musculature and muscle atrophy. Electrical muscle stimulation (EMS) interventions for improving muscle performance and motor unit activity patterns are widely known and performed. Especially, the portable EMS device is convenient because people do not need to go to the hospital and/or clinic for EMS intervention. However, there are few reports about the effects of the portable EMS device on muscle strength and locomotor activity in locomotive syndrome.

Purpose: The aim of the present study was to quantify the effect of an EMS intervention using a portable device on muscle strength and activation patterns in individuals with the locomotive syndrome.

Methods: Nineteen female subjects were randomly assigned to two groups: the intervention group (n = 10; age = 71-82 years) and the control group (n = 9; age = 70-84 years). Subjects in the intervention group used the portable EMS device to stimulate bilateral quadriceps muscles for eight weeks (23 minutes/5 days/week). The control group did not perform the intervention. To evaluate the effects of EMS, the following measurements were made at baseline, eight weeks and 12 weeks: locomotive syndrome assessment scores, knee extensor strength, vastus lateralis muscle activation patterns during a submaximal isometric knee extension contraction using multi-channel surface electromyography, and muscle thickness.

Results: The locomotive syndrome assessment scores, muscle strength, muscle thickness, and muscle activity patterns of the intervention group were significantly improved after eight weeks as compared to the control group (p 0.05). However, these results were not sustained at 12 weeks.

Conclusion(s): The EMS intervention resulted in increased locomotor assessment scores accompanied by enhanced muscle strength, muscle thickness, and changes in muscle activation patterns in locomotive syndrome subjects. Our results suggested that an EMS intervention is potentially useful for improving the neural activation of muscle and force output in locomotive syndrome subjects. Future studies intervention combinations (e.g., EMS and exercise training vs EMS alone vs exercise training alone) and double blinded study design (tester and subject) are needed to establish the most effective methods to treat locomotive syndrome subjects.

Implications: The EMS intervention showed improvement of muscle performance and instrumental activities of daily living in locomotive syndrome subjects. Therefore, it is possible that this method may extend healthy life expectancy in elderly people.

Keywords: Locomotive syndrome, electrical muscle stimulation, elderly people

Funding acknowledgements: This research was supported in part by the Japanese Society for Musculoskeletal Medicine (grant number 3010526).

Topic: Older people; Older people; Musculoskeletal: lower limb

Ethics approval required: Yes
Institution: Hiroshima University
Ethics committee: Hiroshima University’s Committee on Ethics in Research
Ethics number: C-151

All authors, affiliations and abstracts have been published as submitted.

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