1. Putting the palms of your hands together and pushing hard for 1 minute is an: Isometric exercise
2. Using dumbbells to strengthen the arm muscles is an: Isotonic exercise
3. Performing push-ups is an: Isotonic exercise
4. Flexing your stomach muscles for 30 seconds is an: Isometric exercise
5. Performing 30 sit-ups is an: Isotonic exercise