title: A Mechanical model for flexible exercise bars to study the influence of the initial position of the bar on lumbar discs and muscles forces.
abstract: A single-degree-of-freedom model is considered for flexible exercise bars based on the lumped-element approach. By considering the side segment of a flexible bar as a cantilever beam with an equivalent mass at the free end, its free-vibration response, as well as the forced response under the excitation of the grip, are expressed parametrically. Experiments are performed on a particular flexible bar (FLEXI_BAR) in order to obtain numerical values for quantifying the model's parameters. The model is also computationally simulated to study the response of the flexible bar to various excitations. The results are imported into a multi-segment musculoskeletal software (AnyBody), where the effect of different initial hand positions on the lumbar disc and back muscle forces is investigated (including Longissimus, Iliocostalis, and Transversus) during up-down exercises. The results show that all intervertebral discs and muscles forces are more sensitive to the horizontal position of the bar as compared to its vertical position.
authors.forename: Kinda
authors.initials: K
authors.lastname: Khalaf
authors.forename: Masoud
authors.initials: M
authors.lastname: Abdollahi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Nikkhoo
authors.forename: Maryam
authors.initials: M
authors.lastname: Hoviattalab
authors.forename: Mohsen
authors.initials: M
authors.lastname: Asghari
authors.forename: Sajad
authors.initials: S
authors.lastname: Ashouri
authors.forename: Seyedhassan
authors.initials: S
authors.lastname: Nikpour
authors.forename: Sedighe
authors.initials: S
authors.lastname: Kahrizi
authors.forename: Mohamad
authors.initials: M
authors.lastname: Parnianpour
mesh_terms: D001696:Biomechanical Phenomena; D005081:Exercise Therapy / Q000295:instrumentation*; D018737:Hand Strength; D006801:Humans; D007403:Intervertebral Disc / Q000502:physiology*; D008159:Lumbar Vertebrae / Q000502:physiology*; D055595:Mechanical Phenomena; D008954:Models, Biological; D009132:Muscles / Q000502:physiology*; D014732:Vibration