Balthazard P, et al. BMC Musculoskelet Disord. 2012;13(162).
This is a well documented paper and well worth the 27 pages (Email firstname.lastname@example.org for a copy). 42 patient randomized to receive manipulation / mobilization (including muscle energy to the pelvic and PA mobilizations to the spine) followed by active exercise or detuned ultrasound followed by active exercise. Exercise included: mobility, passive stretching, motor control, stability, and strengthening. 8 sessions over 4 to 8 weeks. Manual therapy group had better immediate analgesic effect, lower disability and a trend toward lower pain.
Conclusion - manual therapy is beneficial