What is ADHD? ADHD (attention deficit-hyperactivity disorder) affects both adults and school-aged children. Symptoms include restlessness, difficulty paying attention, and hyperactivity. The causes of ADHD are unknown, however factors such as diet, environment and genetics may contribute to symptoms.
The knee muscles control how the knee joint and patella move. There are two main groups of muscles, the quadriceps and the hamstrings, as well as a small muscle behind the knee (popliteus).
The hamstrings are the opposing muscles, or antagonists, to the quadriceps muscles located on the front, or ventral, side of the leg. When the quads contract to extend your knee, they pull your leg up and allow you to move it away from your body. In this way, they are the prime mover, or the agonist.