Flight attendants report on high physical load and complaints particularly focussing on the lower back. These findings are mainly ascribed to pushing and pulling of trolleys during the ascent and descent flight phases. Within an interdisciplinary experimental study, the load on the lumbar spine of flight attendants during trolley handling aboard aircraft was analysed based on laboratory measurements regarding posture and exerted forces as well as on subsequent biomechanical model calculations. Forces and moments of force at the lumbosacral disc were quantified for 458 manoeuvres performed by 25 flight attendants in total (22 female, 3 male). Lumbar load varies according to handling mode (pushing, pulling), floor gradient (0°, 2°, 5°, 8°), trolley type (half-, full-size trolley), trolley loading (empty, medium, full) and, in addition, according to individual execution technique. For each of the resulting 48 task configurations, lumbar load was evaluated with respect to potential biomechanical overload by applying work-design recommendations for disc compression and moment of force. Irrespective of floor inclination, trolley weight and individual performance, pushing of small trolleys is combined with acceptable lumbar load, pulling with critical load. Pushing or pulling large trolleys occasionally yield to critical lumbar load, in particular, when heavy or heaviest containers are moved on relatively steep or steepest surfaces. To diminish overload risk relevantly, top-edge grasp positions should be avoided for pulling of half-size trolleys, whereas for the other cases, grasping at the upper edge of the trolley is recommended. Relevance to industry The provided study illustrates lumbar load of flight attendants during trolley handling aboard aircraft for typical task conditions and individual execution techniques. Specified hints for work design regarding posture and grasp position enable to avoid biomechanical low-back overload for flight attendants. Furthermore, trolley properties may be reconsidered, regular maintenance of rollers should be guaranteed.