 The EMG of lumbar multifidus will be recorded 3 times at rest first prior to each of muscle activation conditions: 1 verbal instruction only, and 2 combined tactile stimulation and verbal instruction. For both the muscle activation conditions, the participant will be asked to assume a starting position: abduct the contralateral shoulder and flex the contralateral elbow to approximately 90. The contralateral side will be opposite to the painful side of patients with LBP or the left side of the asymptomatic participants. If the patient has bilateral LBP, the contralateral side will be the less painful side. 