Hmm, your brake system may need some adjusting. Most looms require a fairly firm pressing but it should not be terribly difficult to step on the brake release lever and release tension. What brand model of loom do you have? Does the manufacturer have drawings you can reference for how the brake is to be set up or adjusted?
Most looms have the brake release and crank on the same side of the loom so it is possible to step on the brake with left foot and crank on with right hand. Some looms have a lever that can be engaged to keep the brake off. Leclerc is one.