<i>Jinkyo</i> , a Japanese Traditional (Kampo) Medicine Concept That Is Analogous to Sarcopenia: Its Utility in Daily Practice and Its Physical Background

ABSTRACT Background Early detection of sarcopenia is important to prevent frailty. In Japanese Traditional (Kampo) medicine (JTM), weakness of the lower abdominal region (WLAR) is considered a sign of the JTM concept jinkyo, which is similar to sarcopenia. Patients and Methods We enrolled consecutive 100 patients (50 males, 50 females) who underwent abdominal X‐ray computed tomography (CT) at our institution in 2015–2021. We divided them into three groups according to the WLAR findings. The CT visualized a cross‐sectional area of the iliopsoas muscle and six independent parameters representing the size of the rectus abdominis muscle (RA). We analyzed the relationships between WLAR levels and sarcopenia state which was determined from the psoas muscle index, six RA muscle parameters, six other parameters, and the area of the iliopsoas muscle. Results In both males and females, our analyses detected a significant increase in the sarcopenia fraction with the advance of WLAR findings. Among the six RA parameters, upper‐ and lower‐part dehiscence of the muscles in females and lower‐part dehiscence in males showed significant differences as WLAR findings. A multiple linear regression analysis demonstrated a significant correlation between the iliopsoas‐muscle area and lower‐part thickness of the RA in females and lower‐part dehiscence in males. Conclusion The WLAR assessment, which is routinely performed in JTM, successfully screened sarcopenia. The jinkyo state defined by the WLAR is easy to identify in routine JTM practice, and JTM medicines for the jinkyo state may be effective remedies for sarcopenia in elderly people.