A pilot study of posture change when wearing high-heeled shoes and pantyhose

Women desire to be taller and to make their legs look longer, so they often wear high-heeled shoes and pantyhose. Our ultimate goal is to develop a pantyhose that reduces muscle fatigue when wearing high-heeled shoes. We applied the panty part of the support half pants that we developed in 2016 to the development of this sample and designed two types of pantyhose based on the appropriate pressure value that changes for each body part. (Mitsuno et al., 2018, 2022). When myoelectric potentials were measured at 8 points in the lower extremities at this time, there was a significant positive correlation between muscle activity in bare feet and muscle activity when wearing high heels and pantyhose B/when wearing low heels and pantyhose A. From this, even if we wear high-heeled shoes, we can reproduce muscle activity close to that of bare feet by wearing pantyhose that matches the shoes. We thought that this change was related to the change in posture when wearing shoes and pantyhose and investigated the change in posture and the use of muscles. Two-dimensional postural images of the right half of the participant's body were taken. To define the orientation of the participant's head and trunk, a 50 cm square was drawn on the floor and a vertical line was added through the midpoint of top side. The participant was instructed to stand across this line so that the front-back median plane of the participant was projected onto the floor, and to look forward. In addition, a guide rod was worn on the top of the participant's head along the anteroposterior median plane, and the line passing through the vertical midpoint of the square at the foot and the guide rod on the top of the head was aligned with the position which they were so as to always overlap or be in equilibrium. The standing position was corrected using two mirrors so that the head and body would not twist. Reflectors (10 mm diameter hemisphere made own) are placed at 10 points: the vertex of the head, acromion, lateral malleolus, the midpoint of the waist/groin/knee/calf, pelvic head, anterior superior iliac spine, and posterior superior iliac. The participant's posture was photographed under 12 conditions when wearing two types of stockings: barefoot, running, low-heeled shoes, and high-heeled shoes. We assumed that the angles formed by the body axis I connecting the acromion point and the waist, the body axis II connecting the acromion point and the calf, and the line connecting the iliac crest and the anterior superior iliac spine are angles a and b, respectively. In addition, the horizontal distance between the lateral malleolus and the vertex/acromion was determined. When correlation coefficients between these four observation items were calculated, there was a significant positive correlation between angles a and b, and there was also a significant positive correlation between the horizontal movement distance of the top of the head and the acromion point. There was also a significant negative correlation between the angle a/b and the horizontal movement distance of the vertex. From that, the smaller the angles a and b, then the more the pelvis rotates forward, and the more the head moves forward. When wearing pantyhose, angles a and b become smaller, that is, the pelvis rotates forward and the posture of the lower leg changes, but the balance is achieved by changing the position of the head and shoulders. When the participant wore high heels and become taller, her shoulder moved back to balance the forwardly moving head. In the future, it is necessary to increase the number of subjects and classify them according to their standing posture while barefoot and investigate these relationships.