The Russian bar is a circus discipline practiced by three artists. Two porters propel a flyer by manipulating a flexible bar placed on their shoulders. The asymmetric forces to which they are exposed can ultimately lead to chronic lower back pain. The aim of this thesis is to study the intervertebral loads to which the porters are subjected using biomechanical modeling. A trio of Russian bar artists was recruited to participate in data collection, including motion capture and electromyographic measurements. A musculoskeletal model developed in the OpenSim software was then adapted to the loading conditions imposed by the Russian bar (high force and speed). The external forces applied to the shoulder were estimated indirectly through a mechanical characterization that revealed a linear deformation behavior of the bar. A numerical method was used to estimate the ground reaction force. The results show that there are no significant differences in the lumbar loads generated by candle jumps and salto, but a significant difference between the different phases of jumps, namely, propulsion and landing. The propulsion phase is the one that exerts the most forces on the participants' vertebrae, with an average maximum force of 12571.7±1714.5 N in compression. Furthermore, despite the extreme forces experienced by the artists, shear forces are low (<1000N), which can be explained by their technique. Artists and coaches must be aware of the severity of the forces involved and adapt training to the skills and physical condition of the artists.
| Date | 24 Jan 2023 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Éric Wagnac (Supervisor), Marion Cossin (Co-supervisor) & Michel Behr (Co-supervisor) |
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Schmidt, P. (Author),
Wagnac (Supervisor), Cossin (Co-supervisor) & Behr (Co-supervisor),
24 Jan 2023Student thesis: Master's thesis › Master in Engineering: Engineering