Periodic limb movement disorder-A disorder characterized by involuntary flexion of leg muscles, causing twitching and leg extension or kicking during sleep.
This complex dance step combines an arched back with a leg extension or kick.
Legs: Leg extension machine -- two sets of 12-15 reps.
At home, lunges can take the place of the leg extension machine.
The quadriceps are located in the front of the leg and provide leg extension.