RESUMEN
BACKGROUND: Pain relief is important both for the movement of patients suffering from low back pain and the quality of life. Dry needling is effective on myofascial trigger points but its effect on the area of pain and the functional balance is not fully known. OBJECTIVE: To examine the immediate effect of dry needling on pain and functional balance of patients suffering from low back pain. METHODS: Twenty five patients with sub-chronic low back pain were randomly divided into two groups: the intervention or control group. Needles were used for the participants of the intervention group, bilaterally at the spinus level, one and a half finger breath from the midline in levels L2-L5 of the lumbar spine. A third line of needles was inserted in the interspinosus spaces, except L5-S1 level. Bipedal stance, lateral loading and mediolateral body sway were assessed using a pair of force plates. Pain tolerance was assessed using an algometer. RESULTS: The pain tolerance significantly increased in the intervention group from (M = 4.87, SE 0.663) to (M = 6.52, SE 0.547) (F(1,23) = 7.8, p< 0.05) after intervention. During mediolateral body sway the force signal in the dominant frequency significantly increased in the intervention group from (M = 43.2, SE 4.6) to (M = 54,9, SE 3.6) (F(1,23) = 4.63, p< 0.05) after intervention, exhibiting more controlled rhythmic behavior. CONCLUSIONS: Dry needling in painful areas and penetrating all the muscle groups seems to improve pain and functional balance, yet its effect on specific muscles needs to be studied further.