Reviews published in 2013 and 2015 evaluating evidence for MFR efficacy found that clinical trials that had been conducted varied in quality, technique, outcome measurements, and had mixed outcomes; the 2015 review noted: "it is time for scientific evidences on MFR to support its clinical use." Another review concluded that the use of foam rollers or a roller massager before or after exercise for self-myofascial release appears to be helpful with regard to range of motion and soreness, but the optimal timing and duration of use requires further study.