The ab bench is also known as an adjustable sit-up machine, as you can adjust (increase or decrease) the angle of the bench. A steep angle adds more resistance and hence, is harder to work on. Likewise, a wider angle is easier to do and more appropriate for beginners. They assist in strengthening the core muscles.The free weights are the barbells and dumbbells in the gym, while the machines are any resistance-based workout machines such as the leg press, assisted chin up machine, or lat pull down. There are two types of resistance machine: plate loaded and pin loaded.
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