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Dynamic Knee Stability and Perturbation Training

Dynamic Knee Stability and Perturbation Training. Dynamic Knee Stability. Rudolph et al, KSSTA 2001 31 active subjects 10 uninjured 11 copers 10 non-copers Screening evaluation Quadriceps strength testing Knee joint laxity testing. Testing. EMG testing Normalized to maximum EMG

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Dynamic Knee Stability and Perturbation Training

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  1. Dynamic Knee Stability and Perturbation Training

  2. Dynamic Knee Stability • Rudolph et al, KSSTA 2001 • 31 active subjects • 10 uninjured • 11 copers • 10 non-copers • Screening evaluation • Quadriceps strength testing • Knee joint laxity testing

  3. Testing • EMG testing • Normalized to maximum EMG • Variables • Muscle onset (threshold 2.5x ave rest EMG) • Termination of activity • Magnitude (Integration over weight acceptance interval) • Co-contraction of VL-LH, VL-MG

  4. Testing • 3D motion analysis • Self-selected walking, jogging speeds • Joint motions, moments • Support moments

  5. Walking *Control group different from copers and non-copers (P<0.05) **Non-copers' involved side different from all others (P<0.05)

  6. Walking Distribution of support moments on the involved side during weight acceptance, walking. Non-copers* had lower knee moments (F=5.402, P=0.045) and higher hip moments (F=3.979, P=0.056) than copers or uninjured subjects

  7. Walking

  8. Walking • Regression analyses • 79.5% of the variability in the knee moment at peak knee flexion accounted for by the variability in the onset-to-peak of the hamstrings and quadriceps muscles (F=6.009, P=0.030) in the copers only.

  9. Jogging

  10. Jogging Knee flexion Knee moment

  11. Jogging Non-copers had significantly greater hip (F=3.3994, P=0.030) and less knee (F=4.727, P=0.017) extensor moments on the involved sides

  12. Jogging Non-copers had significantly greater co-contraction between vastus lateralis and medial gastrocnemius in the involved limb (*F=3.609, P=0.041)

  13. Jogging • Regression analyses • 83.5% of the variability in the knee moment at peak knee flexion accounted for by the variability in the amount of VL-LH and VL-MG co-contraction (F=15.231, P=0.004) in the non-copers only.

  14. Conclusions Copers Non-copers • Normal knee motions and moments • Less co-activation • Muscle activation-important factor in stability • Compensation related to quadriceps strength, passive knee laxity • Reduced knee flexor moment • Reduced knee motion • Transfer control to hip • Possible delayed force production?

  15. Perturbation training • Fitzgerald et al, PT 2000 • 26 subjects completed training • 14 subjects in standard group • 12 subjects in perturbation group • Screening exam • Pass “rehab candidate” criteria

  16. Training programs Standard program Perturbation training • Resistance training to quads and hams • Cardiovascular endurance training • Agility training • Sport-specific skill training • AP, ML on Balance Master • AP, ML rotary on tiltboard • Rollerboard/Platform • Multi-directional on rollerboard

  17. Treatment outcomes • Unsuccessful rehab • Episode of knee giving way • Status reduction from rehab candidate to high risk for reinjury on retesting • Outcome measures • MVIC quadriceps • Single-limb hop tests • Knee joint laxity • KOS-ADLs • KOS-Sports • Global Rating Scale

  18. Results Greater number of subjects in the standardgroup had unsuccessful rehabilitation (χ2=5.27, critical value=3.84,P<.05) Positive likelihood ratio was 4.88 ([11/18]/1–[7/8])

  19. Results KOS-Sports interaction. P=.12 KOS-ADLS interaction. P<.05

  20. Results GRS interaction. P<.05 X-over Hop interaction. P<.05

  21. Hop Testing * P<.05 at follow-up

  22. Conclusions • More subjects in standard group (50%) had unsuccessful rehab compared to pert group (92%) • ~5x more likely to successfully return to high-level activities if receive perturbation training • Pre to post training • ADLs, GRS, X-over hop improved in both groups • Post training to follow-up • Maintained in pert group, in standard group

  23. Development of Dynamic Stability • Chmielewski et al, J Electromyo & Kinesiology 2002 • 9 subjects • Passed screen and wanted to attempt to return to activity • Quadriceps strength testing • Screening exam

  24. EMG testing • VL, LH, MG, SOL • Muscle timing onset • Termination of activity • Muscle activity duration • Time to peak amplitude • Peak amplitude • Integral of muscle activity during loading response

  25. Training • Perturbation training • Agility training • Resistance strength training for quads, hams, and gastrocs

  26. Screening examination P<.05

  27. EMG testing * VL integral of activity during walking is significantly increased after perturbation training (p<0.05) VL activity integrated from 100 ms before initial contact to peak knee flexion is less before training (a) compared to after training (b).

  28. EMG testing Timing of muscle activity during walking before and after perturbation training

  29. Conclusions • Quadriceps activity integral after training • Relationship of quadriceps activity, peak magnitude, time-to-peak activity with hamstrings and soleus activation • Influenced by training • Self-reports sports , functional test

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