The gluteus medius muscle is an important muscle that dampens and stabilizes the lateral inclination of the pelvis during one-leg standing and walking. Defining the internal structure of the gluteus medius muscle, muscle output and electromyographic waveform characteristics leads to appropriate improvement of the examination method in clinical practice and better interpretation of the examination data, and can contribute to improvement and prevention of functional disorders such as instability and fall.Macroscopic anatomical investigations revealed that the aponeurosis was present inside the gluteus medius and divided into anterior and posterior bundles. In the measurement of muscle cross-sectional area and electromyography at the time of maximum abductor abduction, the data were estimated that the anterior fiber bundle mainly contributed to the hip extension position and the posterior fiber bundle mainly contributed to the hip flexion position. The myoelectric potentials of both fiber bundles of the gluteus medius during walking had individual characteristics of the subjects, but reflected the characteristics at the time of maximum muscle strength.

[Purpose] This study aimed to investigate how the speed alteration task, which gradually increases or conversely decreases walking speed, affected walking stability. [Participants and Methods] Thirteen healthy young adults performed two walking tasks as follows: the speed alteration task, in which the walking speed was gradually increased or decreased, and the speed constant task, in which the walking speed was maintained at a comfortable level. Before and after each task, the Timed Up and Go test was performed to analyze time, walking speed, and trajectory. The overall score of the Timed Up and Go test, as well as the scores of the three major segments (i.e., forward, turning around, and return), and nine subsegments, were calculated and analyzed. [Results] During the speed alteration task, parameters including time and walking speed of the Timed Up and Go test were significantly improved. Also, the same parameters increased significantly in the forward and return segments. These increases were also observed in the first subsegment of the forward segment and the second subsegment of the return segment. [Conclusion] The speed alteration task improved walking stability, so it could be used in gait training to improve walking stability.

Few previous studies have delimitated the palpation zone of the gluteus medius muscle with a focus on its fiber bundles. The purpose of this study was to clarify the morphological characteristics of the gluteus medius muscle using an anatomical approach, and to define its proper palpation zone. [Participants and Methods] In this study, we evaluated thirteen halves of the pelvic region in seven formalin-fixed cadavers. We identified the borders between the iliotibial band and gluteus medius muscle, and between the gluteus medius and gluteus maximus muscles, on the iliac crest. Furthermore, we quantified the border points of the gluteus medius' fiber bundles and observed its anatomical and morphological characteristics. [Results] We identified two fiber bundles in the gluteus medius muscle, an anterior and a posterior fiber bundle, and detected that a portion of the posterior fibers was located subcutaneously. [Conclusion] We propose that the region where the posterior fibers of the gluteus medius muscle are located subcutaneously is an appropriate zone for the palpation of this muscle.