IntroLeg tension is an important part of executing a proper stance.
- Inner tension occurs when the tension in the legs and feet is directed inward toward the centerline, as in the cat and sanchin stances.
- Outer tension occurs when the tension in the legs and feet is directed outward away from the centerline, as in the front and sitting stances.
- Individual stances may use either inner or outer tension, but not both.
- Some stances have little or no tension, such as aback stance. Using unnecessary muscles for leg tension will hamper speed, power, and balance, and cause unnecessary fatigue and a lack of control.
Reasons for leg tension
- If a leg is tensioned just before being kicked, it can withstand the kick without collapse.
- When the legs are tensioned as a punch contacts its target, the forces generated by the muscles in the body are effectively pushing against an immovable object, the floor. This means most of the force can be applied to the target instead of being absorbed by loose joints.
Friction’s role in leg tensionSome instructors speak of squeezing the feet into the floor while creating leg tension to strengthen the stance. Some claim this acts as a suction cup to make the body more solid on impact, so it may resist any attacking force by using friction. Sound like pseudoscience to me!
Friction is the interaction between surfaces, expressed as a coefficient of friction. It relates only to the type of materials, the smoothness of the surfaces, and their geometry. You cannot change the composition of your feet or the floor, or the coefficient of friction between them, but you can change the geometry by maximizing your foot’s contact with the floor; therefore, don’t curl the toes, or rise on the balls or heels of the feet; you want your feet as flat as possible for maximum contact.
Does leg tension and the pushing of the feet outward or inward against the friction between the feet and the floor exert any greater force to the floor or increase the friction? The downward force that acts on your feet is your mass, which doesn’t change unless you lose weight. However, extra force can be created by the sudden contraction of muscles, such as when you jump. I have a 25-pound terrier that likes to retrieve. Sometimes, when he’s getting ready for the command to go, he stands with a rear paw on my foot. That’s only about 8 pounds of pressure so I don’t notice it until I say, GO! Then the downward pressure of his launch feels like a horse stepped on my foot and it really hurts. This increase in downward force against an immovable object (the floor) increases your mass and thus the friction but applying leg tension and pushing inward or outward has little effect on the friction.
Leg tension stiffens the legs but whether this strengthens the structure of the stance or increases stability is debatable. Some would argue that the increased muscle tension creates a more stable structure. Others would argue that the tensions counteract each other in opposite directions and accomplish nothing. Others argue that too stiff a stance structure may weaken the stance, and that continually pushing against the friction of the floor contact is reducing the amount of force necessary to break that contact to the floor and allows the feet to slip.