As a massage therapist I see and hear a lot about low back pain.  Often problems arise when combining lifting and twisting, but why?  

One theory is that the weakness vs. strength imbalance between postural and phasic muscles in and around the pelvis perpetuates instability, strain and altered movement - accounting  for re-injuring of these key structures.   There are 33 [amazon-product region="us" text="muscles that attach to the pelvis" type="text"]0805350861[/amazon-product] and when the relationships between agonists and antagonists become altered, you get postural distortion and painful movement patterns.

 If you take a look at the muscles of the low back there is one in particular that stands out, the Quadratus Lumborum - or QL -  connects the pelvis to the spine. 

 Functionally, it  extends the lower back when contracting bi-laterally.  They also pick up the slack, as it were, when muscle fibers of the erector spinae are weak or inhibited.  Constant contraction while seated can overuse the QLs, resulting in muscle fatigue.    A contracted QL may have decreased bloodflow and adhesions in the muscle and fascia may develop in time,  which may result in muscle spasm. 

Stretching and strengthening the Quadratus Lumborum  are indicated for low back pain.   Also, the use of  Heat packs and ice  applied to the effected area,.  Massage and other manual therapies should be considered, as results are often felt within moments and repeated treatment can lead to long-lasting results.