We all want a flat tummy, but let's face it, core exercises like crunches ... 4'11" and 5'4" tall, a 65 cm ball if you're between 5'4" and 5'11" tall, or a 75 cm ball if you're between 5'11 ...

For strength, mobility or recovery sessions, these are the best exercise balls you could add to your home gym. You may think the exercise ball – often also called a Swiss ball or gym ball ...