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).
At the back of the leg behind the thigh there are three muscles known as the hamstrings.These muscles have a lot to do with how flexible we are.The three muscles, semitendinosus, semimembranosus, and biceps femoris (which has two heads) flex the knee and extend the hip (except for one head of the biceps femoris). The hamstrings also cross and act upon the joints of both the hip and the knee.We are looking at three muscles with four attachments.hese muscles have a lot to do with how flexible we are. The three muscles, semitendinosus, semimembranosus, and biceps femoris (which has two heads) flex the knee and extend the hip (except for one head of the biceps femoris).