Background: Unstable shoes, which have recently become popular, claim to provide additional physiological and biomechanical advantages to people who wear them. Alterations in postural stability have been shown when using the shoe after training. However, the immediate effect on muscle activity when walking in unstable shoes for the first time has not been investigated. Objective: To evaluate muscle activity and temporal parameters of gait when wearing Masai Barefoot Technology shoes (R) for the first time compared to the subject's own regular trainer shoes. Study Design: A pilot repeated-measures quasi control trial. Method: Electromyographic measurements of lower leg muscles (soleus, medial gastrocnemius, lateral gastrocnemius, tibialis anterior, peroneus longus, rectus femoris, biceps femoris and gluteus medius) were measured in 15 healthy participants using Masai Barefoot Technology shoes and trainer shoes over a 10-m walkway. Muscle activity of the third and sixth steps was used to study the difference in behaviour of the muscles under the two shoe conditions. Temporal parameters were captured with footswitches to highlight heel strike, heel lift and toe off. Paired samples t-test was completed to compare mean muscle activity for Masai Barefoot Technology and trainer shoes. Results: Indicated that the use of Masai Barefoot Technology shoes increased the intensity of the magnitude of muscle activity. While this increase in the activity was not significant across the subjects, there were inter-individual differences in muscle activity. This variance between the participants demonstrates that some subjects do alter muscle behaviour while wearing such shoes. Conclusion: A more rigorous and specific assessment is required when advising patients to purchase the Masai Barefoot Technology shoe. Not all subjects respond positively to using unstable shoes, and the point in time when muscle behaviour can change is variable.
