The participant will lie prone and the HILT will be administered in two preliminary test locations. In order to evaluate any possible adverse reactions, the initial treatment location will be delivered at a decreased intensity at two separate locations above the target treatment areas. The Power for these two locations will be at a half dose (22 W) for one minute each. The initial, half dose treatment area is indicated by the Blue circles in the image below. Upon conclusion of the initial test treatments (at half dose), the skin with be evaluated for excessive redness or any other changes in skin appearance. Also, the participant will be asked about any discomfort. Should no unanticipated changes in skin appearance occur and the participant reports no discomfort, the treatment will be administered. The process of applying the laser at half dosage will occur prior to each treatment.

The participant will lie prone and the Placebo HILT will be administered is the same capacity as the treatment group however no Laser treatment will be administered. Upon conclusion of the placebo treatment, the skin with be evaluated for excessive redness or any other changes in skin appearance. Also, the participant will be asked about any discomfort.

• The participant will lie prone and the HILT will be administered in 9 symmetrical positions which cover the lumbosacral region. Dose will be 1minute per position. The dose will include:

  • Power (44 Watts)
  • Mode (continues wave)
  • Time on (60000 ms)
  • Time off (1 ms)
  • Repeats (9)

• Distance of electrode from skin will begin 10" from skin surface. The participant may or may not feel mild warmth. Should the subject report excessive warmth or discomfort the probe distance will be increased in 2" intervals until it is comfortable. The entire process will take approximately 10 minutes.

• The participant will lie prone and the Placebo treatment will consist of positioning the HILT probe over the 9 symmetrical positions for 1 minutes each however the no laser will be admitted.

EMG will be recorded during all submaximal and maximal strength testing. EMG will be assessed using wireless Bluetooth electrodes that will be attached using double-sided adhesive stickers. All submaximal and maximal strength testing will be performed using a hand-held dynamometer (Microfet 2 Manual Muscle Tester). Subjects will be stabilized using a nylon strap, the same material and mechanism as a seat belt, when necessary to eliminate accessory or compensatory motion during strength testing. This will be placed on their anterior and/or medial thigh with padding to eliminate any discomfort where the strap contacts the skin.

Change in total hemoglobin will be used as an index of change in regional blood volume.will be assessed using near-infrared spectroscopy (NIRS) (Portamon, Artinis Medical Systems, Arnhem, The Netherlands).

Muscle edema will be assessed via ultrasound using the echo intensity function. Ultrasound images will be obtained using a portable brightness mode (B-mode) ultrasound-imaging device (GE Logiqe, USA) and a multi-frequency linear-array probe (12L-Rs; 5-13MHz; 38.4 mm field-of-view). Ultrasound images will be analyzed using ImageJ software (Version 1.47v., National Institutes of Health, Bethesda, MD, USA). Echo intensity, as assessed by gray-scale analysis (0 arbitrary units [AU], corresponds to black image, 255 AU corresponds to white image) will be performed using the histogram function and will be determined from the same region of interest as muscle thickness.

Muscle sensitivity will be measured with a handheld digital algometer (Wagner FDX-25 pressure algometer- Wagner Instruments, Greenwich, CT) and be applied at a right angle to the skin surface with the subject lying in prone position at 3 locations on the Paravertebral muscles, Quadratus lumborum, and Piriformis. Pressure will be applied at a rate of 30 kPa/s, which corresponds to 3 N/s.

Measure self reported perceived disability via a standardized survey form that can report a raw score between 0 and 50 points.