Muscle Strengthening sessions should be a minimum of 8-10 exercises using the major muscle groups. Ideally use some sort of resistance (such as a weight for arm exercises) and do 8-12 repetitions of each exercise. The level (weight) of each exercise should be so that you can do 8-12 repetitions before the muscle group gets tired. So, for example, for the upper arm muscles, hold a weight in your hand and flex (bend) your arm up and down 8-12 times. This should make your arm muscles tire.
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