NIOSH (1997) identified the relationship between low back disorders and occupational risk factors. The five risk factors included for this review are: (1) heavy physical work which is defined as work that has high energy demands
or requires some measure of physical strength, (2) lifting and forceful movements, (3) bending and twisting (awkward postures), (4) whole-body vibration (WBV), and (5) static work postures. Many of the studies addressed multiple workrelated factors. Heavy physical work and awkward postures are the main causes of low back pain. Low-back disorders are associated with work-related lifting and forceful movements.