A method of adjusting a length of at least one safety harness strap with an adjuster comprises positioning the adjuster at a desired location along the at least one strap, winding the at least one strap about the shaft, and locking the shaft with the locking mechanism to prevent rotation in an unwinding direction. The at least one strap is selected from the group consisting of at least one shoulder strap, at least one chest strap, at least one waist strap, at least one seat strap, and at least one leg strap. The adjuster includes a base, a shaft rotatably operatively connected to the shaft and defining a slot configured and arranged to receive the at least one strap, and a locking mechanism interconnecting the base and the shaft. The locking mechanism allows rotation of the shaft in one direction and prevents rotation of the shaft in an opposite direction.