Dissection: Leg

We dissect and examine a frog's leg and muscles. The skin is removed and the leg is bent back and forth to see how pairs of antagonistic muscles work. Biology - Human Body - Learning Points. Muscles contract to cause movement. Muscles are connected to bones by tendons. Muscles can only contract and relax. Muscles are found in antagonistic pairs and can be classified as flexors or extensors. A Twig Experiment Film. Let students experience real experiments in lab conditions anywhere, from setup, method all the way through to analysis and real-world application.