CYBEX VR Owner's Manual page 16

Closed Kinematic Chain Leg Extension
• Hip/Knee Extension - The quadriceps are
responsible for extension of the knee joint.
The gluteus maximus and hamstring are
responsible for hip extension. The hip-knee
relationship in closed kinematic chain extension
represents an indirect proportion. An increase
in hip motion will increase hip extensor work
and proportionally decrease knee extensor
work, and vice versa.
• Knee Tracking - Functioning as a hinge, it is
imperative that the knee be directed toward the
toes when eccentrically flexing or concentrically
extending during closed chain movements.
Exactly which toe(s) the knee is to be directed
towards is dependent upon the anatomical
structure of the user. It is commonly suggested
that the knee track between the big and
second toes. However, if a marked Q-angle is
noted, tracking is recommended more toward the fifth (little) toe. Comfort is also a factor
in the decision. Ultimately, once the proper tracking has been determined, it must be
monitored and maintained throughout each repetition.
• Range of Motion - The range of motion is limited by spinal alignment during eccentric
flexion and at full knee extension concentrically. Hyperextension of the knee is to be
avoided in closed chain leg work.
• Associated Muscles - Hip adductor involvement varies with foot placement. As the feet
are placed wider and the knees track accordingly, hip adduction is increased.
Exercises
Page 2-2
Cybex VR Owner's Manual
MUSCLES TRAINED