CYBEX VR2 User Manual

CYBEX VR2 Owner’s Manual
The Quadriceps
• Knee Extension - The quadriceps are respon-
sible for extension of the knee joint. Although
the vastus medialis and vastus lateralis are
pulling at slightly different angles on the
patella, the knee joint functions as a hinge.
Attempts at emphasizing either of these two
muscles by altering knee alignment will have
limited effect on the muscle and detrimental
effects on the joint itself. It should be noted
for alignment purposes that the axis of the
knee joint is actually near the posterior aspect
of the knee.
MUSCLES TRAINED
• Range of Motion - The normal range of motion is generally considered to be -10 to
135 degrees. Unless a restriction occurs or is prescribed, range of motion is limited only by
the user’s ability to control the quads concentrically into full extension and eccentrically
into flexion. Full extension on the Leg Extension (an open chain exercise) does not place
forces on the knee that furthers hyperextension, as is the case in a closed chain exercise. In
full extension, the least compressive force is placed on the patella. As range of motion
increases, the compressive forces on the patella increase. Ninety degrees (where patellar
compression equals eight times the resistance applied) is often regarded as being the end of
safely resisted extension, however, this remains an individual matter. Normal cruciate liga-
ments safely counter shearing forces developed in this exercise. The hamstring can be a lim-
iting factor in achieving full knee extension if the hip is positioned at 90 degrees.
Exercise
Page 3-6

CYBEX VR2 Specifications

General

Category	Fitness Equipment
Frame Material	Steel
Weight Stack	Varies by model
Dimensions	Varies by model
Weight Capacity	Varies by model
Color Options	Varies by model
Warranty	Varies by model
Adjustability	Yes