protectivearts

SIZE MATTERS

Coaches always look quizzically when they see me approach my boys. The polite ones catch themselves, but inevitably ask, “Where do they get their height?” My boys are both over 6′ and have at least 8″ on me when they stand up straight. At 15, Kyrian is still filling out, but is whip-strong lean fromContinue reading “SIZE MATTERS”

CAMMING ACTION

The banner image shows a cam with a flat follower. Cams are used to convert rotary to linear motion. As the cam rotates, the follower rises and falls: Abrupt changes in the cam’s velocity results in large accelerations and cause the follower to jerk or chatter. In operating machinery, that is not a good thing, butContinue reading “CAMMING ACTION”

JO TORI

The jō 杖 (“wooden staff”) is a walking stick usually about four feet in length. It is unclear precisely how it became incorporated within Aikido. While some of the jō movements come from spear-fighting (yarijutsu 槍術), and others from staff-fighting (jō-jutsu 杖術 and bō-jutsu 棒術), many of them are most similar to the use of a bayonet (jūken-jutsu). Jō tori is takingContinue reading “JO TORI”