I confess to having a fetish with putting my body under load in various ways while syncing it up to kinky music. Kind of weird behavior though we are all adults here ;-). This is a simple drill that I occasionally work into my routine to challenge trunk strength and control while superimposing lower extremity movements. All you need is a flat bench and you are in business! Naturally folks, will tend to overarch their back, which is by no means the devil though something that you should aim to minimize, especially if you do not tolerate spinal extension. If this particular version of the exercise is too difficult, modify the exercise by reducing the excursion of the leg movements or slide up on the bench. As always, wishing you HAPPY, HEALTHY, & STRONG TRAINING!