Effects of Wearing Raised Heel Insoles (RHI) for a Long Term on Physical Functions: Focused on an Adult Male in Their Twenties
The objective of this study was to evaluate the effects of the long-term wear of raised heel insoles (RHI) on the changes in overall body functions and mechanical adaption. Methods: This study measured pelvic range of motion (ROM), balance, sensory, ankle joint ROM, lower back pain (LBP), muscle tone, and the muscle stiffness and decrement of male subjects in their 20s. The subjects wore RHI (5cm) for 8 hours per day for 8 weeks (60 days) and measurements were conducted three times (0th, 30th,
... times (0th, 30th, and 60th days from the experiment start date). Results: Pelvic ROM increased and static balance decreased when the duration of wearing the RHI increased. Moreover, when the duration of wearing the RHI increased, the sensory function of twopoint discrimination (2PD) decreased, the state of tension of the medial gastrocnemius (MG) increased, and the dynamic stiffness worsened. Conclusions: This study provides baseline data for presenting guidelines for preventing the musculoskeletal deformity and degeneration of the body by revealing changes in overall physical functions due to the extended wearing of RHI. Background In the 20th century, men have become increasingly interested in their appearance. Consequently, they have been pursuing the aesthetic beauty of personality and fashion by using high-heeled (HH) shoes and insoles. It is for men to settle dissatisfaction in their physical appearance and gain confidence using raised heel insoles (RHI), just as women wear high-heeled shoes . As men use RHI more frequently for a cosmetic purpose rather than functional purposes in daily life, people, regardless of gender, are more exposed to the risk of musculoskeletal disorders  . Various RHI are sold in the market. Interestingly, it was reported that men (70%) purchased RHI more than women (30%) did. Particularly, men in their 20s accounted for 30% of the total sale , and men preferred 3 and 5cm the most . Insoles were originally designed and developed for satisfying a functional objective to prevent muscle fatigue by distributing body weight and protect ankle and knee joints by absorbing impacts. However, as more people are interested in the appearance, young men often use high-heeled shoes and RHI to overcome dissatisfaction with height and gain confidence in their body [1, 5]. Wearing high-heeled shoes weakens the anterior tibial muscle, changes the dynamics of the feet, and decreases the muscle strength of lower extremities, resulting in imbalances in lower extremity alignment. Garn et al  reported that it could cause various changes to the musculoskeletal system (e.g., muscle weakness, ligament injury, ankylosis, and improper body alignment) and chronic ankle instability. Jung et al  analyzed the effects of RHI on the overall body functions and showed that it affected balance ability, sensation, and range of motion (ROM). Ankle instability damages joint movements and positional sensation, changes the local sensation of the ankle joint, changes the feedback system between the ankle joint and the central nervous system, and affects the recognition of it. The impairment of the sensory feedback hinders the ability to coordinate movements and adapt properly . It was also reported that the common habit of wearing high-or low-heeled shoes affected healthy women in their 20s to decrease the sensitivity of the somatosensory system and reduce the balance ability . Wearing high-heeled shoes makes it hard for the lower extremities to make an ideal walking condition, changes the center of body's gravity by altering the positions of the spine and lower extremity joints , raises the medial arch , puts more weight in front of one's feet while walking , decreases stability, and generates compensation in the knee and hip joints . Lee et al  showed that wearing 4cm-thick insoles increased pelvic ROM. The results indicated an increase in the forward bending of the lumbar spine and they concluded that wearing tall insole negatively affected the spine. The sacroiliac joint needs the stability of ligaments and muscles because it has high mobility anatomically  . Kim et al  reported that spinal curvature was changed according to pelvic ROM and caused a lower back pain by increasing shearing force and changing the structure to stress the posterior ligaments and the posterior joints. High-heel changes the center of gravity (COG), increases the center of body mass (CBM), and hinders ideal walking [16, 17] . Nashner  indicated that maintaining balance is a process generated by the coordination among senses, movement, the central nervous system, and dynamic aspects. Wearing high-heeled shoes None.