Tohoku University confirms leg strength enhancement through incorporation of samurai Rei-ho etiquette

The Rei-ho etiquette practices that were once essential to the life of samurai have been revealed to be beneficial for modern health promotion. A research team led by Ayaka Ogasawara (Graduate Student at the time of the research) and Akira Sato (Part-time Lecturer at the time of the research) from Tohoku University School of Medicine and Specially Appointed Professor Ryoichi Nagatomi, Director of the Designing Future Health Initiative at Tohoku University's Head Office of Enterprise Partnerships, confirmed that implementing training based on etiquette (Rei-ho) squatting and standing movements for three months results in an average improvement of more than 25% in leg muscle strength. These results can be achieved with just 5 minutes or so of exercise per day and are easy to incorporate into daily life, making it a promising new method for preventing falls and muscle strength decline in old age. The research was published in The Tohoku Journal of Experimental Medicine.

In Japan, daily activities once naturally included many squatting movements, such as sitting in seiza (formal kneeling position), sleeping on a futon, and using Japanese-style toilets, which had the effect of strengthening the lower limbs. However, due to the Westernization of lifestyles, with the widespread adoption of chairs, beds, and Western-style toilets, opportunities for such movements have greatly decreased. On the other hand, there exists a movement system called Rei-ho that was passed down by samurai. In this form of etiquette, daily movements such as standing, sitting, and walking are emphasized to be performed slowly without momentum. While this may appear to be an inefficient movement, it was also a device for maintaining leg and hip strength.

To verify what effects simple exercises incorporating Rei-ho would have on leg muscle strength, the research team conducted a randomized controlled trial. They divided 34 healthy adults aged 20 to 64 years with no experience in Rei-ho into a training group (17 people) and a control group (17 people) that continued their usual lifestyle.

The Rei-ho training group continued exercises incorporating Rei-ho for about 5 minutes per day, four or more days per week, for three months. The content consisted of performing chair sitting and standing movements 10 times and squatting and standing movements 10 times, increasing to 12 times from the third week onward. All movements were characterized by being performed slowly at a constant speed without leaning the upper body forward significantly, based on Rei-ho principles. Meanwhile, the control group did not perform special exercises and continued their usual lifestyle. Knee extension strength was measured before and after training.

As a result, after three months, the Rei-ho training group showed an average muscle strength improvement of 25.9%, while the control group had only a 2.5% increase. This demonstrated that training incorporating Rei-ho is an effective method for enhancing leg muscle strength despite being implementable easily in a short time.

Since chair sitting and squatting are movements repeatedly performed in daily life, it is considered that leg strength can be trained naturally by consciously incorporating Rei-ho into daily life, not just as training exercises. Furthermore, etiquette, which combines cultural value and health benefits, has the potential to become a new health resource that attracts attention not only domestically but also from overseas.

Journal Information
Publication: The Tohoku Journal of Experimental Medicine
Title: A Traditional Japanese Samurai Movement Rei-ho as a Knee Extension Strength Training: A Randomized Controlled Study
DOI: 10.1620/tjem.2025.J099