As a trainer you're always looking for the most effective exercises. That's why you may want to use the physioball when training new female exercisers, according to research published in the November 2003 issue of the Journal of Strength and Conditioning Research (vol. 17, pp. 721-5). The study found that, in a 5-week exercise program using the physioball, untrained women achieved greater gains in torso balance and electromyography (EMG) activity than women who performed traditional floor exercises witho1itthe ball. (EMG measurements show the amount of electrical activity on the surface of an active muscle.) The experimental group did curl-ups and back extensions on the physioball while the control, group performed the same exercises on the floor. The physioball group was found to have a significantly greater change in EMG flexion and extension activity and greater balance scores than the floor exercise group.