Lumbar spine loads during education and training with self-contained breathing apparatus

Objective: German fire fighters often complain of lumbar back pain after tr aining with a self-contained breathing apparatus while using a device calle d 'Schlag-hammer' (SH). We investigated whether this training produces an e xcessive load on the lumbar spine. Method: We developed a model to estimate the load on the lumbar spine using a vector model similar to Jager et al.'s model. The force at the SH's cabl e was recorded on-liner and the position of each subject was registered wit h synchronized series of photos. The influence of the different parameters was calculated by varying these data (+/-10%) and computing the model. Results: There is no dangerous load for healthy persons using a correct tec hnique. Improper technique, however, caused by exhaustion or ignorance, can result in high peaks of lumbar spine load. Conclusions: The lumbar spine loads involved are acceptable if the exercise is performed with a straight back without bending of the lumbar spine and without sudden acceleration. The direction of the pull should be towards th e lumbar spine.