Transcript Quadriceps strengthening and knee biomechanics during stair ascent and descent - WCB 2014

Quadriceps Strengthening Does Not Change Quadriceps and Knee Biomechanics During
Stair Ascent and Descent in Adults With Knee Osteoarthritis
1
DeVita ,
1
Leonardis ,
2
Henriksen ,
2
Bartholdy ,
1
Rider ,
2
Jørgensen ,
2
Bliddal ,
Paul
Josh
Marius
Cecilie
Patrick
Lars Bo
Henning
Shane
1
2
1
Rabideau , & Jens Aaboe
Biomechanics Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC, USA
2The Parker Institute, Department of Rheumatology, Copenhagen University Hospital, Frederiksberg, Denmark
Introduction
Results
Knee osteoarthritis (OA) causes pain, reduced function and
quality of life and is associated with reduced quadriceps
muscle strength. Quadriceps strengthening is
recommended as treatment of these negative outcomes
based on the widely accepted hypothesized mechanism
that increased quadriceps strength increases quadriceps
force and negative muscle work in locomotion, supposedly
reducing knee joint loading and mediating clinically
beneficial effects. We propose this mechanism to be flawed
in that increased muscle force would increase joint loading
and negative muscle work does not reduce joint loads but
total body mechanical energy. The purpose of this study
was to assess the effect of quadriceps strengthening
on quadriceps muscle force, power and work and knee
joint forces in stair ascent and descent. These tasks are
quadriceps-demanding and include both concentric and
eccentric contractions.
Ascent
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Descent
Quadriceps Force
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Quadriceps Power
Figure 3 – Mean quadriceps strength. # = significant group x time
interaction, p<0.05, * Post > Pre, Trained only, p<0.05
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Tibio-femoral Contact Force
Methods
32 participants (18 females, age 57 yrs, BMI 27.1 kg/m2)
with physician diagnosed tibio-femoral knee OA were
randomly assigned to strengthening or non-training control
groups after providing written informed consent. All
participants were pre- and post-tested over a 12 week
interval with WOMAC (pain and function), isokinetic
quadriceps strength, 3D motion capture, and force platform
instruments. Strength training consisted of supervised leg
extension, leg press and lunge exercises (fig 1) three times
per week with three sets of ten repetitions and loads
increasing from 65% to 80% of 3RM. Maximum quadriceps
force, power and total work and tibiofemoral contact forces
during stair ascent and descent were assessed with a
biomechanical model (1). Data were analyzed with two-way
ANOVAs (Group by Time) for ascent and descent with
Tukey post hoc tests following significant interactions, all at
p<0.05.
Figure 4 – WOMAC pain & function. # = significant group x time
interaction, p<0.05, * Post < Pre, Trained only, p<0.05
Conclusion
Despite significant improvements in quadriceps
strength, pain, and function in the strength training
group only, no significant interaction, group, or time
effects were observed in maximum quadriceps
force, power, work and knee loads in either stair
ascent or descent. Our data refute the concept
that the mechanical function of the quadriceps
muscle in locomotion is altered after
quadriceps strengthening in knee OA patients.
Improvements in pain and function following
quadriceps strengthening are therefore not due
to altered quadriceps or knee biomechanics
during daily activities but to another, as yet
unidentified mechanism.
References
Figure 1 – Strength training exercises.
Figure 2 –
Stair ascent & descent
simulations & videos
Ascent
Descent
Figure 6 – Stair ascent and descent maximum forces
and powers. There were no significant interaction or
main effects for these variables, p>0.05.
1. Messier, et al, Osteoarthritis & Cartilage, 2011
Lab
website
Figure 5 – Stair Ascent: Quadriceps force & power and knee contact
force. Solid lines represent pre-test means, dashed lines represent
post-test means, and dotted lines represent one pre-test SD
Lab
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