George is lifting weights. He starts by doing biceps curls which involves flexing his elbows. His elbow is able to bend because the humero-ulnar joint is a hinge joint. Sam is doing leg presses, extending his knees as he pushes against the weights. Meanwhile, Jane is doing "lat pulls" by pulling downward on a weighted bar. This movement involves adduction of her arms. Her shoulder joint is a ball-and-socket joint, allowing a wide range of movements.
