Accomodating resistance equipment
Some experts argue that constant resistance exercise is more natural than any other weight lifting program because leverage imbalances match the actual day-to-day movement of the body.
Variable Resistance Devices: "When you hoist a weight by pulling on a cable that goes over the top of a pulley and is attached to a weight, you're engaged in constant resistance training" (source: International Sports Sciences Association; 2001).
For example, when doing dumbbell curls the amount of muscular force required is much greater at the bottom of the movement (when the dumbbells are at waist level) than it is at the top of the movement (when the dumbbells are near the chin).
As the dumbbells approach the top of the movement, leverage improves and the user doesn't have to work as hard.
static resistance is any exercise with force that has no movement.
anything with only a barbell or dumbbell is constant resistance.Critics respond that since everyone is different is size, stature and strength it is virtually impossible to match everybody's leverage with machine leverage.