Twenty athletes with low back pain were randomized to receive the Mézières method (n=10) or isostretching (n=10). The primary outcome of interest was pain (numeric rating scale). Secondary outcomes included perceived exertion (modified Borg scale) and trunk mobility (flexion, extension, bilateral rotation, and inclination) measured with a wearable sensor at baseline, 2, 4, 6, and 12 weeks (over a 12-week intervention). Overall, the results of the study revealed significant pain reduction over time in both groups, with a greater reduction in the isostretching group, and time- and group-specific gains in trunk mobility, notably larger right and left rotation at 6 weeks in the Mézières group. In short, both programs were effective; Mézières showed advantages for rotation measures at mid-intervention, whereas isostretching reduced pain more.