Paraspinal muscle function and pain sensitivity following exercise-induced delayed-onset muscle soreness.

PURPOSE: The aim of this study was to evaluate the effectiveness of an exercise protocol designed to induce delayed-onset muscle soreness (DOMS) in paraspinal muscles and its effects on low back functional capacities.

METHODS: Twenty-four healthy participants were asked to perform four series of 25 trunk flexion-extension in a prone position (45° inclined Roman chair). The protocol was performed using loads corresponding to participant's trunk weight plus 10% of their trunk extension maximal voluntary contraction. Perceived soreness and pain were assessed using an 11-point numerical analogue scale three times a day during 5 day post-DOMS protocol. Pressure-pain thresholds (PPT) in paraspinal muscles (L2 and L4 bilaterally) and the vastus medialis (control site), and trunk extension maximal voluntary contraction were assessed 24-36 h post-protocol and compared to baseline (t tests).

RESULTS: Muscle soreness (3.8/10) and pain (2.1/10) peak scores were observed 24-36 h post-protocol (mean of 28 h). A significant reduction in trunk extension maximal voluntary contraction was observed post-protocol (p = 0.005). Significant reductions in PPT were observed post-protocol for all trunk extensor sites (ps < 0.01), but not for the control site (p = 0.40).

CONCLUSIONS: The exercise protocol efficiently led to low back muscle DOMS, reduced functional capacities, and increased pain sensitivity locally. Such protocol could be used as an efficient and safe experimental low back pain model.