known as power resistance bands. These are essentially like large, wide elastic bands. They are similar to standard therapy bands but are looped round to form a long, continuous loop. This can make them easier to anchor to things and means you don't need to worry about tying and untying knots. Loop resistance bands often come with an anchor set to make it even easier to attach to doors for increased versatility. known as power resistance bands. These are essentially like large, wide elastic bands. They are similar to standard therapy bands but are looped round to form a long, continuous loop. This can make them easier to anchor to things and means you don't need to worry about tying and untying knots. Loop resistance bands often come with an anchor set to make it even easier to attach to doors for increased versatility.