hi, as you mentioned you are having poliomyelitis and the leg has become weaker and you need know the exercises for it. Well, telling just a regular leg exercises will not help. as it is a years of time where the muscle is progressively becoming weak to first thing here is to check the muscles which are activated. also by doing an EMG and NCV we will come close to find out which muscles are in active state to implement the proper exercise. Learning exercises for individual muscles will help provide input. Also, PNF exercises will work and extend the strength in muscle. It will be a slow and gradual way of getting strength. Also I am currently seeing the patient with same issues. We are working with different protocols. Only looking for leg Strengthening is not sufficient as body works as a unit. Using an electric stimulation to the muscles which may take some time for muscles to accept and reflect the improvement will take some time but performed along with exercise have helped my.patients to a degree. I will recommend to meet a physical therapist and get the assessment of muscles done and you can also learn exercises for individual muscles which later on you can do at home. with the game of God I wish you a speedy recovery