Portable Low-Level Laser Therapy for Recovery After a Quadriceps-Dominant Fatiguing Task in Recreational Runners

This randomized, sham-controlled, two-period crossover study evaluated the effects of portable 808-nm low-level laser therapy (LLLT) on acute recovery and running biomechanics following a quadriceps-dominant fatiguing task in recreational runners. Twenty male recreational runners completed both active LLLT and sham conditions, separated by a 2-week washout period. After the fatiguing task, participants received 10 minutes of bilateral quadriceps LLLT or sham treatment, followed by treadmill running at the same fixed self-selected speed. Quadriceps soreness, heart rate, running spatiotemporal parameters, and kinematic responses were assessed using a verbal numerical rating scale, heart-rate monitoring, two-dimensional video analysis, and inertial measurement units.

Inclusion Criteria: 1. Male recreational runners aged 18-40 years. 2. Recreational running status determined using the World Masters Athletics (WMA) age-graded performance score, with an age-graded score below 60%. 3. Previous experience with treadmill running. 4. Rearfoot-strike running pattern. 5. No running-related lower-limb injury during the preceding 6 months Exclusion Criteria: 1. WMA age-graded performance score of 60% or higher. 2. Non-rearfoot-strike running pattern. 3. Leg-length discrepancy greater than 3 cm. 4. Use of an orthosis, brace, or other lower-limb medical device that could influence running gait.