Kendo is the traditional Japanese art of swordsmanship, and is translated literally as “the way of the sword”. Kendo practitioners are referred to as kendoka or kenshi.
Kendo is regularly practiced to discipline the human character by applying the principles of the Japanese sword (katana). The purpose is to mold both the body and mind, while cultivating a strong spirit.
The practice of Kendo comes with a variety of physical challenges that could lead to injuries. These challenges come from various factors such as practicing on hard wooden floors, repetitive movements, inadequate post training cool down, use of additional equipment, and ignorance to of minor injuries.
Through the practice of swinging the bamboo sword (shinai), repetitive overhead movement of the shoulder may easily occur more than 500 times within a standard 2 hour training session. Such repetitive movement may cause inflammation of muscles, tendons, bursa, ligaments and other structures when the kendoka does not possess good control of the shoulder or have proper technique. Rotator cuff muscles perform the control of the shoulder blade, which requires specific strengthening program to ensure optimal movement of the shoulder.
Basic cutting practice known as Suburi is performed as much as a 1000 times a session. Suburi places the elbow in extreme stress, especially the wrist extensors, with a high frequency of big angular changes on top of the quick gripping movement (tenouchi) at the end of suburi. This therefore may lead to tennis elbow, scientifically known as extensor tendinopathy, which has been shown to be a degenerative condition of the elbow extensors.
Suburi also causes repetitive stress on the structures within the wrist (Itadera et al., 2001). Additionally, direct blows are received during practice and competitive matches into the wrist joints, which may lead to traumatic and overuse injuries of the wrist.
Low Back Pain
The incidence of low back pain is very high in kendoka, mainly due to the shear stress at the intervertebral joint of the third and fourth levels, as well as the facet joints (Kishi et al., 2009). The activation of core muscles is very important in the prevention of low back pain.
Ankle and Foot Pain
Kendokas have a high risk of problems in their arches and feet - high as 83.3% - but are usually not seen in athletes with less than three years of training experience (Kishi et al., 2002). The right foot stamping action, fumikomi ashi, can occur up to 400 times within a session, and each time the foot hits the floor, it receives an impact that is up to four times body weight (Nunn et al., 1997). Kendokas are at high risk of repetitive strain injury to the foot, such as plantar fascitis, an inflammation of the fascia.
What can be done?
Warm ups are important as part of injury prevention and performance optimization with delayed onset muscle soreness (DOMS) being very common post kendo training. Warm ups need to include dynamic stretching, as static stretching has been shown to impair Kendo practice.
Cool downs and stretching
Adequate cool down and stretching helps to reduce heart rate and promote recovery to return the body to a pre-exercised level. They also help to reduce soreness, increase flexibility and minimize injury rates.
Functional Core and Body Biomechanics
Strong core muscles and optimal body biomechanics are essential in the practice of Kendo, to allow optimal energy transfer and stability throughout the movement. A strong core means a strong body foundation; the foundation for all Kendo movement. A functional core with optimal body biomechanics that supports your body when practicing Kendo will help to improve your Kendo performance while minimizing injuries.
Functional range, strength and conditioning
It is important to maintain optimal muscle extensibility and muscle strengths for the practice of Kendo. Specific stretching and the implementation of a strengthening program that is tailored to each individual will help prevent injuries from affecting your training regimes.
… and most importantly… NEVER IGNORE MINOR INJURIES.
List of References
Itadera, E., Ichikawa, N., Hashizume, H., & Inoue, H. (2001). Stress fracture of the ulnar styloid process in kendo player – a case report. Hand Surgery, 6:109-111.
Kishi, S., Yoshikawa, N., Chiba, S., Kashiwagi, M., Wada, T., Sakai, N., Sumiya, H., Fujiwara, M., & Hirohashi, K. (2002). A study of the lower leg and foot pains in kendo athletes – influence of kendo steps on the foot arch in a certain growth period. Japanese Journal of Clinical Sports Medicine, 10(1): 82-89.
Kishi, S., Ikuhiro, M., Kyosuke, T., Tsuyoshi., Y., & Toshiaki, S. (2009). Factors responsible for lower back pain in kendo practitioners. Journal of Physical Therapy Science, 21(2): 147-154.
Nunn, N., Dyas, J., & Dodd, I. (1997). Repetitive strain injury to the foot in elite women kendoka. British Journal of Sports Medicine, 31:68-69.
B.Biomed, Doctor of Physiotherapy, APAM