Lumbar Multifidus Muscle Thickness During Graded Quadruped and Prone Exercises

Exercises for lumbar multifidus (LM) muscle are important for injury and low back pain prevention and treatment. This study examined the differences in LM contraction thickness between variations of the superman and bird dog exercises. Twenty-one recreational athletes performed the superman exercise from the prone position with the following grading: rest, right upper extremity lift (RU), right lower extremity (RL) and upper and lower extremities lift (UL). They also performed the following bird dog variations from the quadruped position: rest, RU, RL and left upper - right lower extremity lift (LURL). LM muscle thickness of both sides was recorded using two ultrasonography (US) devices. LM thickness during superman-UL, was significantly greater compared with the other exercises and significantly lower during upper extremity exercises compared with lower extremity exercises (p < 0.05). No significant differences in LM thickness between sides was found (p > 0.05). The US measurements of LM thickness displayed good to excellent intrarrater reliability for both muscle sides. It appears that superman-UL is the most effective exercise for a greater contraction thickness of LM. Further, in order to progressively increase LM muscle thickness, upper extremity tasks should be performed prior to lower extremity tasks and combined upper and lower lifting tasks.