Objectives: To test if the Kinesio Tex Gold ® is able to change the electromyographic signal of iliocostalis and longissimus muscles in patients with chronic nonspecific low back pain.

Study design: Three-arm, randomized controlled trial with a blinded assessor.

Location of study: Physical therapy Clinic of the Universidade Cidade de São Paulo (UNICID)

Patients: Sixty-three patients with chronic nonspecific low back pain.

Intervention: Patients allocated to the Kinesio Taping® group will receive the tape as described by the manufacturer's manual. The patients assigned to the placebo group will receive a Micropore tape and the control group will not receive any intervention. All groups will be assessed before and 30 minutes after intervention

Measures: The following outcomes will be measured: 1) Muscle activity and 2) pain intensity.

Limitations: Therapists will not be blinded.

Patients who are seeking care for low back pain at the physiotherapy clinic from Universidade São Paulo will be invited to participate in the study and informed about the objectives of the study and evaluation procedures.

Patients who agree to participate will sign a consent form.

Patients will be assessed at baseline and immediately after the interventions.

Investigators will collect data with regards to personal and anthropometric data, as well as pain intensity (measured by a 0-10 numerical rating scale in all follow up points) and disability (measured by the 0-24 point Roland Morris Disability Questionnaire at baseline only).

Finally, muscle activation will be evaluated by surface electromyography and the maximum voluntary contraction of the trunk at 30 degrees position for a lumbar dynamometer that will be adjusted to the anthropometric profile of patients. The average and maximum values of muscular strength will be obtained by maximum voluntary contraction. The electromyography will capture the muscle activity in an integrated manner to electrogoniometers and will transmit the data via Bluetooth to a desktop with a MWX8 software (Biometrics) that will analyze the data. Before instrumentation patients will be instructed to perform the trunk extension movement the therapist's commands to become familiar with the equipment. Soon after will be held instrumentation (placement of electromyography electrodes and electrogoniometers and lumbar dynamometer) maximal voluntary contraction will be collected in trunk extension without Kinesio taping

Inclusion Criteria:

• Patients with chronic low back pain (with a duration of at least 3 months), with or without leg pain.

Exclusion Criteria:

• patients who have used the Kinesio Taping previously
• any contraindications to the use of Kinesio Tex Gold®, such as allergy or severe skin problems.
• patients with nerve root compromise
• patients with fracture, tumor, inflammatory and/or infectious diseases
• patients with severe cardiorespiratory and/or metabolic diseases
• previous spinal surgery