Of course it strengthens, like any physical activity strengthens the corresponding muscles. If you are interested in any specific leg muscles (https://ru.wikipedia.org/wiki/Muscles of_the_lower_limbs_human), then you can choose the appropriate technique.
It should be noted that technique is very important. Since with the wrong technique, there will be a greater load on the knee joints, which can do more harm than good.
Run for fun!
Of course, running strengthens the muscles in our body. But keep in mind that you should not expect great results from running in terms of increasing mass.
Running helps tone muscles, causing them to harden and slightly increase in volume. Running also helps to make the body stronger and more enduring.
The muscles that work when running are worked out quite well.