Quad sets or quads sets are knee rehabilitation exercises to keep the quadriceps (quads) muscles from becoming inhibited after injury or surgery.
Positioning for quad sets exercises. Contract the quads and hold the contraction for 10 seconds, if necessary trying to push the knee down onto the bed.
Bending the knee slightly with a soft towel or foam will help the exercise.
Quads muscle inhibition
Impaired functioning of the quads muscle group is thought to arise from central nervous system alterations that can occur after knee injury as a protective mechanism to prevent further injury.
Disinhibitory Interventions and Voluntary Quadriceps Activation: A Systematic Review. Harkey MS, Gribble PA and Pietrosimone BG. J Athl Train. 2014 May-Jun; 49(3): 411–421.