The effect of a training program combined with augmented afferent feedback from the feet using shoe insoles on gait performance and muscle power in older adults: a randomised controlled trial

Background. Aged-related loss of afferent feedback of the feet plays an important role in gait performance. Although strength, balance and gait training can significantly improve the muscle power and functional abilities of older individuals, it remains unclear whether training effects can be enhanced by augmenting afferent feedback from the feet adding shoe insoles complementary to conventional training. Objective. The current study investigated the effect of physical exercise combined with wearing MedReflex (R) shoe insoles on the gait performance and muscle power in older adults. Methods. Twenty-eight independent living, older adults aged 65-91 years were randomly assigned to either an insole group (IG; n = 14) or a training group (TG; n = 14). Further 14 subjects matched to the IG and TG were recruited as a control group (CG; n = 14) (no exercise). The IG and TG completed the same training program consisting of aerobic exercises, progressive resistance strength training and stretching exercises twice per week for 12 weeks, whereas, the IG wore the insoles during everyday life and during training sessions. Assessments included the Falls Efficacy Scale International (FESI), gait analysis and muscle power measurements of the knee and ankle joint at pre- and post-training. Results. There were significant time x group interactions in walking speed, step length and in several muscle power measurements. The positive effects of gait parameters ranged between 1% and 12% and between 1% and 8% and the trend to improvements of muscle power ranged between 15-79% and 20-79% for the IG and TG, respectively. The IG and TG did not differ significantly in their improvements. The CG showed a trend to deteriorations between 0% and -5% for gait parameters and between -4% and -14% for muscle power. No significant change in FES-I score occurred in neither groups. Conclusions. The results of this study provide evidence of significant improvements in gait performance and muscle power after a conventional training program in independent living, older adults. However, there is no additional effect of long-term adaptation of gait caused by wearing insoles concurrent to physical training.