To each their own, but I really don't need more than 10 minutes tops to feel my abs beg (no, demand) for a stoppage to the core workout I'm doing. More important than timing is exercise variety, ...

While sit-ups and crunches are an effective way to train your core, you can work your abs just as well with a standing abs workout, and this 12-minute dumbbell workout not only hits the core but also ...

Bodyweight workouts are ideal if you want to build strength at home without spending any money. There are plenty of free workouts to choose from on YouTube, too, like this 20-minute full-body routine ...