Transcript 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
– 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
Testing
• 3D motion analysis
– Self-selected walking, jogging speeds
– Joint motions, moments
– Support moments
Walking
Coper
Non-coper
Control
Involved
Uninvolved
Involved
Uninvolved
Involved
Uninvolved
Vert GRF at loading
(F=8.499, P=0.017)*
1.25%BW
(±0.030)
1.23%BW
(±0.022)
1.22%BW
(±0.031)
1.26%BW
(±0.033)
1.31%BW*
(±0.031)
1.29%BW*
(±0.033)
Peak knee flexion angle
(negative=flexion)
(F=8.499, P=0.017)**
-22.8°
(±1.9)
-24.5°
(±1.8)
-21.9°**
(±1.9)
-25.9°
(±1.9)
-26.5°
(±1.9)
-26.5°
(±1.9)
Knee moment at PKF
(F=6.212, P=0.034)**
0.368
(±0.07)
0.437
(±0.68)
0.314**
(±0.071)
0.542
(±0.071)
0.558
(±0.074)
0.601
(±0.071)
Soleus integral over wt
acceptance (t=2.894,
P=0.020)**
8.655
(±1.292)
7.489
(±0.679)
9.811**
(±1.362)
6.626
(±0.716)
8.302
(±1.292)
7.612
(±0.679)
*Control group different from copers and non-copers
(P<0.05)
**Non-copers' involved side different from all others
(P<0.05)
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
Walking
Non-coper
Quadriceps strength
(t=4.033, P=0.001)*
Quadriceps index
Lateral hamstrings Onsetto-peak EMG
Coper
75.3% (±11%) 97.1% (±12.7%)
Knee flexion angle
External knee flexion
moment
Copers
Copers
r=0.029, P=0.932
r=0.135, P=0.693
Non-copers
Non-copers
r=0.933, P=0.000*
r=0.716, P=0.030*
Copers
Copers
r=0.672, P=0.030*
r=0.765, P=0.010*
Non-copers
Non-copers
r=0.095, P=0.824
r=0.408, P=0.316
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.
Jogging
Copers
Non-copers
Controls
Involved
Un-involved
Involved
Un-involved
Involved
Un-involved
Velocity m/s per LL
(F=4.00, P=0.03)*
4.041
(±0.23)
4.00 (±0.19)
4.137
(±0.24)
4.236
(±0.21)
4.745*
(±0.23)
4.885*
(±0.19)
Stride length m/LL
(F=4.30, P=0.029)*
3.089
(±0.13)
3.034
(±0.11)
3.194
(±0.18)
3.297
(±0.15)
3.575*
(±0.15)
3.592*
(±0.13)
Vertical ground
reaction force
(F=2.849, P=0.075)
2.172
(±0.07)
2.204
(±0.07)
2.084
(±0.07)
2.156
(±0.07)
2.322
(±0.07)
2.357
(±0.07)
Knee flexion
Jogging
Knee moment
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
Jogging
Peak knee flexion
angle
Copers
Passive laxity
r=0.203, P=1.000
Non-copers
r=-0.866, P=0.015*
Copers
Quadriceps
index
Non-copers had significantly greater cocontraction between vastus lateralis and medial
gastrocnemius in the involved limb (*F=3.609,
P=0.041)
r=-0.133, P=1.000
NS
NS
NS
Non-copers
r=-0.798, P=0.060**
Copers
VL-LH cocontraction
Knee moment
at peak knee
flexion
r=-0.417, P=0.231
Non-copers
r=-0.670, P=0.048*
NS
NS
NS
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 VLMG co-contraction (F=15.231, P=0.004) in the non-copers only.
Conclusions
COPERS
• Normal knee motions and
moments
• Less co-activation
• Muscle activationimportant factor in
stability
NON-COPERS
• Compensation related to
quadriceps strength,
passive knee laxity
• Reduced knee flexor
moment
• Reduced knee motion
• Transfer control to hip
• Possible delayed force
production?
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
Training programs
STANDARD PROGRAM
• Resistance training to
quads and hams
• Cardiovascular
endurance training
• Agility training
• Sport-specific skill
training
PERTURBATION
TRAINING
• AP, ML on Balance
Master
• AP, ML rotary on tiltboard
• Rollerboard/Platform
• Multi-directional on
rollerboard
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
Results
Greater number of subjects in the
standard group had unsuccessful
rehabilitation (χ2=5.27, critical
value=3.84, P<.05)
Positive likelihood ratio was
4.88 ([11/18]/1–[7/8])
Results
KOS-Sports interaction. P=.12
KOS-ADLS interaction. P<.05
Results
GRS interaction. P<.05
X-over Hop interaction. P<.05
Hop Testing
Perturbation
(Immed after)
Single Hop
X-over Hop
Triple Hop
Perturbation
(F/u)
Standard
(Immed after)
101%(±14%)*
105%(±13%)
104%(±16%)
99%(±12%)*
Standard (F/u)
68%(±48%)
100%(±15%)
64%(±55%)
59%(±51%)
* P<.05 at follow-up
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
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
EMG testing
•
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•
•
•
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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
Training
• Perturbation training
• Agility training
• Resistance strength training for quads, hams, and gastrocs
Screening examination
Pre training
Post training
Quadriceps index
90.9%(±12.5%)
91.3%(±5.8%)
Timed Hop
97.3%(±7.95%)
96.0%(±4.9%)
KOS-ADLs
91.8%(±6.6%)
97.3%(±2.3%)*
GRS
83.7%(±13.6%)
94.3%(±4.3%)*
P<.05
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).
EMG testing
Timing of muscle activity during walking before and after perturbation training
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