Participants
neurological disorders or cardiac disease, pain
Twenty healthy young adult males (age: 23.0 ± 0.91) participated in this study. The exclusion criteria were as follows: age < 20 years, no surgery in the year before study participation, history of neurological disorders or cardiac disease, and no back or lower limb pain during standing or gait. All study procedures were approved by the ethics committee of the Tokyo University of Science (21021), and written informed consent was obtained from all participants before the experiment. Power analysis was used to determine the sample size (alpha level: 0.05, power: 0.80, and effect size: 0.40) in this study; the required total sample size was 28. The number of participants in this study was less than the required sample size; therefore, post-hoc analysis for calculating the achieved power was performed based on the results of this study.