Squats - engage your core and keep your back straight, keep your chest lifted as you bend down and push through your heels to return to the start position.
Reverse lunges - step back on one foot at a time, keeping your knees and toes facing straight forward and your chest lifted, push through your front heel to return up.
Squat jumps - squat down low then push your weight up though your heels and jump up off the ground. Land with soft knees and repeat.
Curtesy lunges - step one leg behind and slightly to the side of the other, keep all your weight in your front leg - the back one is just there for support.
Press ups - keep your core tight and your back straight, lower yourself as far down as you can go before pushing back up to the start position. If this is too difficult then perform the exercise on your knees instead of on your feet.
Sit ups - start lying down with your feet flat on the floor and your knees bent. Squeeze your core to help yourself up, then slowly lower yourself back down. There should be no momentum helping you up as all the movement should be coming from your core.
Burpees - lower yourself into a press up position, take your chest all the way to the floor then tuck your feet in and jump up. This should be an explosive and continuous movement.
Mountain climbers - start in a press up position on your hands and feet, run one leg in at a time towards the opposite below, using your course to squeeze your knee to your chest. Your back should be straight and almost parallel to the ground.
Plank - on your forearms and feet, hold the position by squeezing your core and glutes - your back should be parallel to the floor rather than arched up in the air.