1 / 18

Scholes CJ PhD 1,2,3 McDonald MD PhD 2 Coolican MRJ FRACS 1 Parker DA FRACS 1

Efficacy of Repetitive Stepping as a Test of Quadriceps Fatigue: Comparison to Isokinetic Exercise. Scholes CJ PhD 1,2,3 McDonald MD PhD 2 Coolican MRJ FRACS 1 Parker DA FRACS 1 Parker AW PhD 3 1 Sydney Orthopaedic Research Institute

ervin
Download Presentation

Scholes CJ PhD 1,2,3 McDonald MD PhD 2 Coolican MRJ FRACS 1 Parker DA FRACS 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Efficacy of Repetitive Stepping as a Test of Quadriceps Fatigue: Comparison to Isokinetic Exercise Scholes CJ PhD1,2,3 McDonald MD PhD2 Coolican MRJ FRACS1 Parker DA FRACS1 Parker AW PhD3 1 Sydney Orthopaedic Research Institute 2 School of Human Movement Studies, Queensland University of Technology 3Institute of Health & Biomedical Innovation, Queensland University of Technology Australian Orthopaedic Association 70th Annual Scientific Meeting Adelaide, 2010

  2. Conflict of Interest There is no conflict of interest in this research project

  3. Quadriceps Function • Strength and endurance critical to knee function • Implications of dysfunction following surgery • Quadriceps avoidance (Lewek et al 2002) • Joint loading (Shelbourne et al 2004) • Functional instability (Hurd et al 2007) • Endurance improves performance of functional activities

  4. Introduction • Dynamometry – ‘gold standard’ • Limitations • Cost (~$100k) • Space • Dedicated specialist personnel • Need for a clinical alternative

  5. Aim Validate a functional protocol to induce and quantify quadriceps fatigue compared to isokinetic dynamometry

  6. Methods • Participants • Male undergraduates • 20.6+2.5yrs • 1.78+0.05m • 72.3+8.8kg • Repetitive Stepping • Additional Weight • Step Height • Start-end Postures • Speed

  7. Methods • Dynamometry • 50 Repetitions • Concentric-Eccentric • Range-of-motion 900 • Speed 600/sec

  8. Methods - Fatigue Indicators • Peak power • Inverse dynamics • Integrated torque/time

  9. Methods - Fatigue Indicators • Surface Electromyography • Wireless (Zerowire, Italy) • VM, VL, RF • Standardised placement

  10. Methods - Mean Frequency

  11. Results - Peak Power Production

  12. Results - Mean Frequency

  13. Results - Protocol Comparison * ^ ^Significant difference between muscles * Significant difference between stepping and isokinetic

  14. Discussion • Stepping induced greater fatigue compared to previous studies (Coventry et al 2006; Bonato et al 2001) • Isokinetic exercise also induced greater fatigue compared to previous studies (Molinari et al 2006) • Combined eccentric-concentric action • Differential isokinetic fatigue pattern agrees with previous studies (Molinari et al 2006)

  15. Discussion • Lack of studies quantifying fatigue progression in quadriceps during functional task • Parallel fatigue could be related to joint stability and balance during stepping • Increased variability in power production • Load sharing between hip and knee

  16. Conclusions • Stepping protocol valid method to induce quadriceps fatigue • not as effective as isokinetic exercise • Potential future model for clinic-based fatigue assessment

  17. Future clinical tool • Adjustments to the protocol to reduce variability • Validity and reliability for surgically-repaired knees • Modify protocol for patient populations • Effects of rehabilitation • Clinical measurements – fatigue indicators • Steps to exhaustion • Stepping frequency

  18. Thank You

More Related