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 hamstring muscle fibers gradually become tendon fibers near the knee to attach to bone. One can appreciate the thick tendon bands when feeling behind the knee joint. The hamstring muscle is balanced by the quadriceps muscles on the front of the thigh that cause the knee to extend. Together the hamstrings and the quadriceps help control power and stability of the knee joint, allowing activities like walking, running, jumping, and squatting.