The Achilles Tendon – Ways to Help Protect It

This article is about ways to take care of the Achilles tendon. According to the All Japan Kendo Federation (AJKF), among all the injuries that occur in kendo, Achilles tendon-related injuries are the most prevalent at 10.4% [AJKF_InjuryStats] [AJKF_AchillesInjuries] – based on this book published in 2014 [AJKF_MedicalQ&A]. To keep things in perspective, the frequency of injuries in Japan associated with kendo seems significantly smaller relative to that found in many sports according to [AJKF_InjuryStats] [Kanagawa_Stats]. A study in the U.S. published in 2015 shows similar results [Schultzel_KendoInjuries].

With respect to the cause of such injuries, according to [Kendo-Practice_Achilles] (in Japanese),:

I think that the main causes (of Achilles-tendon related injuries) include: “fatigue accumulated around the Achilles tendon from daily training”, “fumikomi when executing a waza,” and “the sudden change of direction during kakari-geiko etc.”
- 主な原因として「日々の訓練の積み重ねにより、アキレス腱・アキレス腱周辺に疲労が溜まった時」「技を決めるときの踏込み時やかかり稽古等での急な方向転換時」などがあげられると思います.

And according to this study of Japanese junior and high school students practicing kendo [Kisi_AchillesKendo], Achilles tendon ruptures “tend to occur when Kendo players make a lunge step forward from the rear position (the fumikomi, I believe) because they assume a ready position with the left foot placed backward the right foot forward.”

My interest in this stems from two recent events. I hurt the Achilles tendon area of my foot (not from kendo incidentally). Second, a sensei ruptured his Achilles tendon during a shiai.

Here’s a compilation of some ways to help protect the Achilles tendon:

Massage Therapy
Warm-up Exercises
Stretches
An “Achilles tendon-friendly” Fumikomi
Other Approaches and Resources
References

Please see the disclaimer below.*

Probably the most important advice is to rest the foot if it hurts. And more generally to listen to the body as described in more detail by Masahiro Imafuji sensei in [Kendo-Guide_Healthy]. Words of wisdom.

Take care of those Achilles tendons!

Massage Therapy

Rolling each foot over a golf ball [Human_Achilles, at 3:43 min] or a sturdy can [Sundial_Achilles].
Massaging the calf muscle using
- a foam roller [Naples_Achilles] [Duke_Achilles, at 3:43mins] or
- a massage therapy ball [Duke_Achilles, at 1:44 mins] [Lexsport_Tutorial]

Warm-up Exercises

Make sure to warm up the calf muscles prior to a vigorous practice and/or stretching.
- This can be done with light footwork e.g. walking, jogging, skipping, squats, suri-ashi, burpees, fumikomi, hopping.

Stretches

It’s probably best to try these slowly and gently at first while avoiding any strain or over-doing it.

The “Standard” standing stretch with the rear leg extended back behind the front leg with the calf muscle and heel stretched.
- I find that I can get a deeper stretch by pushing against a wall with my arms as shown from 0:30 mins in [AskDoctorJo_Achilles].
Heel raises.
- This can be done while standing or while seated on a chair [Dubail_Achilles, 0:19min]. With one or two legs.
Extended heel raises while standing on a stair ledge and holding on to a rail for support [Dubail_Achilles, 0:45min] with one or two legs [Bupa_Achilles].
Yoga poses
- The “downward dog” with alternate extensions of the two heels [SportsWebPT_CalfStretch].
- The forward fold where the front paws of the feet are elevated (e.g. by resting the front paws on a yoga mat and the heels on the ground) [CarolAnn Achilles].

An “Achilles tendon-friendly” Fumikomi

This technique, which also can be used as a form of seme and taught by Nakamura sensei, is described in [KendoNotes ShinkansenFumikomi].
- This approach is much gentler on the Achilles tendon of the rear leg and shifts the burden more to the front leg.
  - The rear foot is involved with a more even and gradual push (rather than an instantaneous and sudden one).
- This approach instead focuses on the hikitsuke – the quick pull of the rear leg and body forward by the forward leg when the forward foot lands.
- I have found this technique very helpful and easier on my rear foot.

Other Approaches and Resources

Taping
- There are many articles and videos explaining this approach including [AJKF_Taping] [Pygeorge_TapingVideo].
- This study [Tsai_AchillesTaping] recommends Athletic Taping (AT) of the Achilles tendon “to protect the Achilles tendon” and Kinesio-Tex Taping (KT) of the Achilles tendon “to speed up kendo striking motion.”
- I have yet to try this.
Achilles Tendon Support
- There are a number of products for supporting the Achilles Tendon including one designed for kendo. This may be a faster and re-usable alternative to taping. The reviews seem positive.
General articles on the Achilles tendon
- [Carey_Calf]

* Disclaimer: the content herein is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.