High incidences of overuse (1,2) and lower back injuries (LBI) have been reported in dance epidemiology.
Lower back injuries have been established as one of the most frequently occurring occupational injuries, and workers with lifting or manual handling duties have been identified as having greater LBI risk.
The peak lumbar anterior shear force (PLASF) generated during lifting has been identified as a predictor of LBI. (14,20) Peak lumbar anterior shear force occurs when a person lifts a load situated in front of his or her body with a flexed trunk posture.
Lumbar compression forces will be referenced to NIOSH normative data as an indicator of male dancer LBI risk.
Any compression force lower than the BCDL of 3400 N indicates a nominal risk to the lifter, whereas compression forces higher than the BCDL require administrative or engineering controls to reduce the potential risk of LBI. A compression force above the BCUL of 6400 N suggests the task poses a serious risk of LBI to the lifter.
Four of the eight male dancers reported having been diagnosed with a LBI by a medical professional at some stage in their career; however, all were injury free at the time of testing.
Forces of these magnitudes indicate a need for administrative controls such as limiting daily lift repetitions in order to reduce the risk of LBI.
The results of this study show that PLASF and high compression forces occur prior (~0.01 sec) to the jump of the ballerina; therefore, the ballerina's jump may be of limited value in reducing LBI risk in male dancers.
This situation may greatly increase lumbar forces and the risk of LBI.