Bodyweight squats work the main muscles in your legs, your calves, hamstrings and quadriceps. Stand with your feet shoulder width apart and stick your glutes out (your butt) or you won’t be able to keep your feet flat on the ground when you bend down. You’ll find that you’ll be able to do a lot of these. I tend to do 3 sets, first one comprising 100, then 70, then 50. You’ll feel it the next day for sure!

Push ups are a great compound exercise. They work all the muscles in your back, shoulders, triceps and to some extent your biceps. Do 3 sets, each time doing as many as you can to failure. This will vary a lot according to the individual. You can mix them up between hands shoulder width apart, wide handed and diamond.

Main muscles worked by the plank are the abdominals; rectus abdominis) and the transversus abdominis. These are the muscles in your belly, and the muscles that sit in between your belly and your side muscles. Stabilising muscles contracted include the obliques in your waist, your hip flexors, your quadriceps in your thighs, the pectoralis major in your chest, and a group of muscles covering your ribcage called serratus anterior, or “boxer’s muscle.”

Hold the plank for a minute without sinking your lower back to avoid injury. You can mix them up by raising your legs either one at a time or alternately. If you want to go nuts, raise your arms out in front as well. You'll be dripping in no time.

Lunges or Power Lunges as Lanre demonstrates here work your glutes in your hips and butt along with the hamstrings and quadriceps in your thighs. The calf muscles in your lower legs, your abdominal muscles and your back muscles act as stabilisers during this exercise. Vary these each week but keep the same technique for 3 sets. Do as many as you can each time with a short break in between. 

Sit ups work all your abdominal muscles when you vary the actions from week to week. The important thing to remember with sit ups is not to strain your neck or back. There's no need for anyone to hold your feet down and the most effective sit ups are done slowly and up to about 45 degrees. Do as many as you can comfortably and aim for 3 sets. Never lose form so don't push it.