I twirling a rope.

We now ,that for a normal life we sleep, eat, drink,and move,and organism reminds me when hungry or fatigue displays,and not always he reacts on hypodynamic or poor move,and therefore to form this itself. And to train you enter slowly, and moves are normal,and after a habits to loads you can to change loads,trains,and in the result metabolism changing. For the result is posture improves, muscle mass raise, muscle capacity, a display net for nerves tissues, improves psychic condition against stress, strengthens bones, tensions, joints, improves oxygen entering in organism.
Therefore are 7 reasons to fight obesity having, and slimming to be a habit days for training. And after,yes muscles will hurt,that milk acid having in muscles and more slags,as if hurt til 3 days,therefore muscles had got microscopic tears, therefore they are long time had not trained. And if hurt is long and does not low,therefore something is not so,and better always to ask a doctor before any training! A best idea for childrens here is jumps through rope,as for strengthening cardiovascular system, loads give for joints, muscles hands,  belly,breast. And improves coordination and force,and big weight fly away.
A first two weeks to ad slowly jumps on two legs at the same time, or alternately on one leg, jump till 2.5 minutes, on every exercise.
On a third week to add for 5 minutes jumps on one leg, on 2.5 every, and jumps with a high raised knees.
On a fourth week ads a jumps crossed ,alternately crossing legs and hands.
Or calculate jumps if clocks do not had near, and 25 jumps are good for one approaches, rhythm is a time from time to change. 
When you will to habit and you will to jump more easy,and to think about new jumps,as to jump to a side, front-back,and over torsion a rope for two time.