 Next, one investigator will prepare the participants skin in the areas of the 2 electrode placements. The skin will be cleaned with isopropyl alcohol. If there is excessive hair, a new disposable razor will be used to shave the hair to improve the quality of the EMG recording. If shaving is required, the investigator will wear gloves to perform shaving following universal precautions. Once the skin is prepared for EMG recording, 2 electrodes will be placed on the skin over the right and left lumbar multifidus at two at the L4-5 level. 