Electrical stimulation of the abdomen preserves motor performance in the inactive elderly: a randomized controlled trial.

Abdominal muscle strength declines easily with the process of aging and/or disuse, and it is difficult to strengthen weak abdominal muscles in the inactive elderly. In the present study, we applied surface electrical stimulation (ES) to the abdomen of inactive elderly people to investigate its chronic effects. Twenty inactive elderly people (65-89 years) who spent most of the day in their bedroom participated in the study. The subjects were assigned to ES and non-ES groups in a random order. In addition to conventional physical therapy and occupational therapy, ES was applied to both sides of the flank of 10 subjects (ES group) for 8 weeks. For evaluation of the abdominal muscles, the cross-sectional area (CSA) was measured with computed tomography and the electrical muscle activity (iEMG) was measured by electromyography. Functional examinations were performed at 2, 4, and 8 weeks after the beginning of the study with the following parameters: grip strength; maximum walking speed (WS); movement time for sitting up (MSU); number of trunk flexions (NTF); flexibility of the trunk; sit-to-stand time (STS); and Barthel index (BI) score. In the ES group, the NTF and MSU were significantly improved at 4 weeks and thereafter. Furthermore, the STS and WS were also improved significantly after 8 weeks (p < 0.05). The CSA and iEMG both increased significantly (p < 0.05). However, the flexibility of the trunk and BI score did not change. In conclusion, ES to the abdomen has the potential to improve motor function in the inactive elderly.