Posterior muscles of the arm that you are writing about are the muscles forming the triceps. They are responsible for such functions as for example straightening of the forearm. That is why firming exercises will be based on the arm straightening movement flexed at the elbow. These exercises are different types of push-ups and body building exercises for example straightening the forearm when leaning forward and various types of so called French lifts, throwing the medicine ball, swimming and a number of different exercises can affect this group of muscles and as a result the whole body would benefit from it.

Summarising, there are many exercises which directly or indirectly affect the triceps if only the straightening of the arm flexed in the elbow takes place. You should remember that these exercises are of firming nature if you perform them with load and they need to include an appropriate number of movements, which initially amounts to 16-20 reps in 2-3 series but it depends on a given exercise or the game you play (basketball will involve triceps most of the time of the game).

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