If you want to use weight machines to work on your core, it is important to know what you are doing. Be sure to talk to a member of staff at the gym if you need help, and make sure you warm up properly before you start exercise.
Abdominal crunch machine
An abdominal crunch machine (often called an ab crunch machine, or just an ab machine) can be used to target your core if you do not want to do sit-ups on a mat, and has the added benefit of encouraging good form while exercising, as well as extra resistance from weights you wouldn’t get with normal sit-ups.
The ab machine consists of a seat with a lower and upper backrest, and either a handle above each shoulder with pads for you to rest your elbows on during the exercise, or a padded bar which goes across the chest. Ensure the machine is adjusted for your size, with your lower back firmly supported by the backrest.
Whilst holding the handles, the exercise is completed by you using your abs to push forwards against the resistance provided by the weights. Complete a rep by slowly returning to the starting position. This machine, unsurprisingly, works your entire core – your abdominal muscles, obliques and lower back.
Back extension machine
A back extension is similar to the abdominal crunch, but works in the opposite way. The bench has pads (connected to weights) which sit against the middle of your upper back.
To do the exercise, start in a sitting position and use the muscles of your back to press against the pads, pushing against the resistance, until your body is at a full extension. You then return back to the start position in a controlled manner, sitting upright.