The producer of Bokushingu’s Kendo TV kindly introduced me to plyometrics several years ago. I had wanted to increase the speed and strength in my footwork and koshi (hips). It is used by those in martial arts and sports such as football, gymnastics, track and field to develop quick and explosive movements [Campbell] [Gymnastics] [Wiki_Plyometrics].
Plyometrics … are exercises in which muscles exert maximum force in short intervals of time, with the goal of increasing power (speed-strength). This training focuses on learning to move from a muscle extension to a contraction in a rapid or “explosive” manner, such as in specialized repeated jumping [Wiki_Plyometrics].
Here’s a handful of videos which demonstrate plyometric exercises for the lower body either on land or in water (for lower-impact to the joints and higher resistance):
- “Kendo Guidance with Tokoro Masataka sensei, Awa Kendo – Win with Footwork,” (所 正孝の剣道指導 ～足さばきで勝つ安房剣道～), tandhnet, Feb 2011 (1:53 mins). (Two plyometric exercises are shown from 0:49.)
“30 Agility Ladder Drills – Beginner, Intermediate and Advanced Variations,” Redefining Strength, Dec. 12, 2014 (6:53mins) (e.g. the single leg hops 0:32, 0:46, skiers 1:17, laterals 2:46, Forwards and backs 6:03).
- “Tony Sands – Explosive Water Training,” June 22, 2014 (2:38 mins). (Water portion starts at 0:54).
Effectiveness. The benefits of plyometrics for “kendo athletes” were investigated in a 2016 study across twelve male and seven female members of the Ibaraki University Kendo Club [Ibaraki]. The study, in Japanese, reported improvements after four weeks of plyometrics training in all of the eight areas measured. For example, the average datotsu execution time for a shoumen-uchi strike, measured by a high-speed camera, improved from 291 msec to 277 msec and the average from-standing jump distance, from 208.5 to 218.6 cm (a 4″ improvement) [Ibaraki, Table 3 on PDF p. 5]. Personally, I have tried several of the exercises and found them quite helpful during a period of more intensive training for shinsa. I noticed that my abs and legs became stronger and my movements, easier and quicker. Since then, I include them periodically when I jog.
Safety Tips. These apply primarily to the land-based exercises and less so to the water-based ones. Because of the power generated, there are a number of safety tips to keep in mind. As described in [Gymnastics] and more fully in [Quinn]: warm-up beforehand, start slowly with smaller jumps (movements or heights) before working gradually towards larger ones, take rests between sets, avoid over-doing them, stop immediately if there is any pain and, most importantly, to land softly. The cited references recommend performing these exercises once every week to once every other day – depending on a person’s skill level and time needed for muscle recovery.
Closing Notes. Stretching afterwards is often recommended by trainers. It apparently “is the best time to make improvements in tissue extensibility” according to a comment by Dr. John Glover [Kendo-Guide_Muscles]. Exercises for the upper body exist also. However, I have not attempted nor felt the need for such exercises thus far as also noted in a comment by Markus “Forget your arms!” in [Kendo-Guide_Muscles]. Finally, the theory behind plyometrics is explained in “The 3 Phases” section of [Gymnastics] and the Methods section of [Wiki_Plyometrics].
[Ibaraki] Nanami MORI, Masahi WATANABE, Nobunao TATSUMI, “Effectiveness of plyometrics training for Kendo athletes,” Faculty of Education Bulletin, Ibaraki University, Natural Sciences, 65: pp. 55-61, Nov 18, 2015. (森奈々実, 渡邊將司, 巽 申直, 剣道におけるプライオメトリックストレーニングの有効性, 茨城大学教育学部紀要（自然科学）65 号（2016）55 － 61, 2015 年 11 月 18 日) (PDF, 8 pages). (in Japanese)
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