You have now worked the major muscles of the body. These exercises are to be done on ALTERNATE DAYS so that the body gets time to recover from the strain.
The trick to strength training is to 'overload' the muscle, to work it until it fails. The human body is such that it adapts to overloading by adapting to face the extra workload the next time round. Our muscles cells react to overload by increasing in size to match the larger cells, thus increasing the overall size of the muscle. Something called 'neural adaptation' also increases the size of the muscles initially. Usually, the bigger the muscle, the stronger it is.
Weight Training in the gym is the best method of building muscles. But, hey! Don't rush to the gym as yet, because if you are below sixteen years of age, you must avoid working out with weights.
The alternative is to do freehand exercises, which are a close second to weight training in efficient muscle building. 'Calisthenics', as these exercises are called, help you build strength rapidly. Select a group of seven exercises that will overload your muscles from arms and shoulders to leg muscles, as described in the illustrations above. Do them as described with a one-minute gap in between sets. HOWEVER, do not get disheartened if you cannot exercise continuously for one minute. As your strength improves, you will be able to slide through these routines.
Do not forget to warm up before doing the strength training exercises and also do not forget to stretch and cool down after the session of strength training exercises is over. I hope you have checked with your Doctor if you are fit enough to do strength-training exercises.