Loading of the knee and hip joint during swimming and water gymnastics

• Applicant: Dr. Ines Kutzner
• Subject Area: Orthopaedics, Traumatology, Reconstructive Surgery
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 262969587

Swimming and water gymnastics are considered to be ideal sports to improve mobility and strengthen muscles, while loading the joints of the lower extremity less than during other sporting activities. The buoyant force of the water reduces the weight force and it is widely believed that this leads to a joint load reduction. The water resistance can in turn be used to strengthen muscles and can be modified by movement speed or surface area.Whether swimming is suitable in the context of rehabilitation after joint surgery or for patients with osteoarthritis is still discussed controversially. On the one hand swimming is considered as a sporting activity without high joint loading and therefore is advised after joint replacement, as well as for patients with osteoarthritis. On the other hand, some studies report high shear stresses in the hip and knee joint during breaststrokes.Knowledge about the joint loading during swimming or water gymnastics is limited and mainly based on calculations using musculoskeletal models, which are subject to many uncertainties. However, facts about the joint loading are necessary to provide evidence-based recommendations for patients with osteoarthritis, following fractures or joint replacement. Using instrumented hip and knee replacements, the joint loading during swimming and water gymnastics can be measured directly. The contact forces and moments can be measured in vivo with a measurement error <2% and are transmitted telemetrically out of the body. As part of ongoing projects instrumented knee and hip replacements were implanted in 19 patients. The existing telemetry system was enhanced for the water use by special induction coils for the power supply and receiving antennas.The goal of this study is to examine whether swimming and water gymnastics lead to low joint loads compared to other sports or everyday activities. Furthermore, the loading during two types of swimming (breast stroke and freestyle leg) will be compared. In the context of water gymnastics, the joint loading during basic movements such as ab-/ adduction, flexion/ extension of the hip and knee joint will be measured in the water. A further goal is to examine how the loading is influenced by increasing water resistance due to increased speed or aids which increase the surface area.The results of this study will allow to provide evidence-based recommendations for patients with osteoarthritis, following fractures or joint replacement, and thus to optimize the course of therapy.

• DFG Programme: Research Grants
• Participating Persons: Professor Dr.-Ing. Georg Bergmann; Jörn Dymke; Dr.-Ing. Friedmar Graichen; Verena Schwachmeyer