Disclaimer: if it’s bulging biceps and a body like Thor you’re after, this little pocket rocket isn’t going to get you very far. However, for strength, flexibility and a quick-fix way to work your muscles when you’re on the move, Activ5 is surprisingly effective.
Isometric exercises are all about maintaining resistance in a fixed position. Using just your bodyweight, you can force your muscles to work against each other for increases in strength and muscular endurance.