Knee
Flexion - Extension
Flexion is
the bending of a part, or decreasing the angle between two parts. You flex your
knee when you bring your leg up toward your thigh.
Range of motion: 140°.
Extension is the opposite of flexion,
describing a straightening movement that increases the angle between body parts.
When standing up, the knees are extended.
Range of motion: 0°.
Extensors: quadriceps femoris
(rectus
femoris,
vastus medialis, vastus lateralis and vastus intermedius); tensor fasciae latae.
Flexors: hamstrings (biceps
femoris,semitendinosus and
semimembranosus); popliteus; gracilis; sartorius.
Mobility tests:
Knee
Identify if caused by 1- or 2-joint muscles.
Strength tests:
Knee
Posture Evaluation: Poor alignment of the knee is likely caused
by problem in the joint below or above it.
FMS: Deep Squat, difficulty
to get back up will indicate a lack of strength.
Inline Lunge: same as for the Deep
Squat.
Hurdle Step: Identify lack
of mobility.
Active Straight Leg Raise:
look for lack of mobility at knee level.
Running
Low
Most of the time, running low, with a small angle of the knee (should be around
150°) is not cause by a limited range of motion of the knee extension but it can
be.
Corrective measures
Mobility:
Standing Hamstring
Stretch, Sitting Hamstring Stretch.
Hurdle Movement (Front Leg)
Hurdling requires a rapid extension of the knee of the attacking leg. Lack
of strength and/or flexibility would results in poor performance or injuries.
The knee flexors (hamstrings) are rapidly stretched at the knee level at the
same time the hip is flexed, compounding the stress on these muscles (remember
that they are 2 joints muscles, dlexing the knee and extending the hip).
Corrective Measures
Mobility:
Standing Hamstring
Stretch, Sitting Hamstring Stretch.
Hyperextension
Knee hyperextesnion can be diagnosed with a posture evaluation. While it
might not affect negatively performance of T&F athletes, it should be addressed
if that position is seen while performing. Bounding and running with the
knee in hyperextension drastically increase the possibility of getting injured.
(Find out more here)