A straight leg raise is knee rehabilitation exercise to strengthen the quads muscles, but it is also used by surgeons to give a quick idea of the activity of the quads after surgery.
Starting position for straight leg raise.
The straight leg being slowly elevated.
Hold in this position for a few seconds and gradually return the leg to the bed.
Quadriceps muscle inhibition
After any insult to the knee, the quads muscle may exhibit reflex inhibition, and appear to be weak. Early encouragement of the quads is essential to minimise the impact on rehabilitation.
Normal inter-limb differences during the straight leg raise neurodynamic test: a cross sectional study Boyd BS and Villa PS. BMC Musculoskelet Disord. 2012; 13: 245.