title: Upper limb joint forces and moments during underwater cyclical movements.
abstract: Sound inverse dynamics modeling is lacking in aquatic locomotion research because of the difficulty in measuring hydrodynamic forces in dynamic conditions. Here we report the successful implementation and validation of an innovative methodology crossing new computational fluid dynamics and inverse dynamics techniques to quantify upper limb joint forces and moments while moving in water. Upper limb kinematics of seven male swimmers sculling while ballasted with 4kg was recorded through underwater motion capture. Together with body scans, segment inertial properties, and hydrodynamic resistances computed from a unique dynamic mesh algorithm capable to handle large body deformations, these data were fed into an inverse dynamics model to solve for joint kinetics. Simulation validity was assessed by comparing the impulse produced by the arms, calculated by integrating vertical forces over a stroke period, to the net theoretical impulse of buoyancy and ballast forces. A resulting gap of 1.2±3.5% provided confidence in the results. Upper limb joint load was within 5% of swimmer׳s body weight, which tends to supports the use of low-load aquatic exercises to reduce joint stress. We expect this significant methodological improvement to pave the way towards deeper insights into the mechanics of aquatic movement and the establishment of practice guidelines in rehabilitation, fitness or swimming performance.
authors: Center of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, and Porto Biomechanics Laboratory, University of Porto, Portugal; Inter-university Laboratory of Human Movement Biology, University Savoie Mont Blanc, Le Bourget du Lac, France. Electronic address: jessy.lauer@gmail.com.
authors: Jessy
authors: J
authors: Lauer
authors: Inter-university Laboratory of Human Movement Biology, University Savoie Mont Blanc, Le Bourget du Lac, France.
authors: Annie Hélène
authors: AH
authors: Rouard
authors: Center of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, and Porto Biomechanics Laboratory, University of Porto, Portugal.
authors: João Paulo
authors: JP
authors: Vilas-Boas
mesh_terms: D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D006801:Humans; D057446:Hydrodynamics; D007101:Immersion; D007596:Joints / Q000502:physiology*; D007700:Kinetics; D008297:Male; D055595:Mechanical Phenomena; D013550:Swimming / Q000502:physiology*; D034941:Upper Extremity / Q000502:physiology*
keywords: Aquatic exercise; Computational fluid dynamics; Inverse dynamics; Joint load