useless. being slanted doesn't work your abs, it works your hips. the crunch at the very top is the only time your abs are working, so the whole rest of the movement is a waste of energy when it comes to ab development.
If you 'roll' up starting head so the curving starts at neck or clavicle, you can get intercostal and upper abdominals to work. But yeah, standard quick situps don't do much.
You are using your arms to propel yourself up when behind the head. It is way more effective if you fold arms across chest!
useless. being slanted doesn't work your abs, it works your hips. the crunch at the very top is the only time your abs are working, so the whole rest of the movement is a waste of energy when it comes to ab development.
If you 'roll' up starting head so the curving starts at neck or clavicle, you can get intercostal and upper abdominals to work. But yeah, standard quick situps don't do much.