The trials suggest that work place exercise is effective , braces and education are ineffective , and workplace modification plus education is of unknown value in preventing low back pain
A systematic review of r and omised controlled trials was undertaken to evaluate the effectiveness of  workplace interventions  to prevent low back pain .
How study design affects outcomes in comparisons of therapy. II: Surgical.
We analysed the results of 221 comparisons of an innovation with a st and ard treatment in surgery published in six leading surgery journals in 1983 to relate features of study design to the magnitude of gain . For each comparison we measured the gain attributed to the innovation over the st and ard therapy by the Mann-Whitney statistic and the difference in proportion of treatment successes . For primary treatments ( aim ed at curing or ameliorating a patient 's principal disease ) , an average gain of 0.56 was produced by 20 r and omized controlled trials . This was less than the 0.62 average for four non-r and omized controlled trials , 0.63 for 19 externally controlled trials , and 0.57 for 73 record review s ( 0.50 represents a toss-up between innovation and st and ard ) . For secondary therapies ( used to prevent or treat complications of therapy ) , the average gain was 0.53 for 61 r and omized controlled trials , 0.58 for eleven non-r and omized controlled trials , 0.54 for eight externally controlled trials , and 0.55 for 18 record review s. Readers of studies evaluating new treatments , particularly for primary treatments , may consider adjustment of the gain according to the study type
The trials suggest that work place exercise is effective , braces and education are ineffective , and workplace modification plus education is of unknown value in preventing low back pain
A systematic review of r and omised controlled trials was undertaken to evaluate the effectiveness of  workplace interventions  to prevent low back pain .