Background and purpose: Chronic non-specific low back pain (CNLBP) is associated with decreased lumbar Multifidus (LM) muscle cross-sectional area (CSA) and Transverse abdominis (TrA) muscle strength which highly predispose the person to recurrent occurrence of disease. We compared the Pilates (PL) and McKenzie (MK) methods on LM CSA and TrA strength in these patients.

Materials and methods: In this clinical trial, 47 female patients, mean age 39.7 years, with CNLBP were allocated to one of three groups including PL training (n=16), MK exercises (n=15), and control (n=16). The measurements of LM CSA and TrA muscle strength were performed using imaging ultrasonography and Bent Knee Lowering Test, respectively at baseline, following a 6-week intervention program, and a follow-up of one month. To evaluate the changes of outcome measurements over time, repeated measures ANOVA test was applied at P< 0.05 in SPSS V. 21.

Results: Compared with MK exercises, PL training could significantly increase right and left LM CSA at L5 level (P< 0.001), while there were no significant effects on this factor in other lumbar segments (P> 0.05). Additionally, PL method significantly increased TrA muscle strength (P< 0.001), however this efficiency was not observed for MK exercises (P> 0.05). The changes were not significantly different after a one-month follow-up (P> 0.05).

Conclusion: PL training can lead to increase in LM CSA and also TrA muscle strength. These effective changes are persistent following one month.

(Clinical Trials Registry Number: IRCT201406169440N4)