Discernible means noticeable. If your extra hours training are having no discernible influence on your basketball game, it means your game has not changed.
You can use discernible in two senses. First, you can use it to describe something you physically see: Because the sky was so clear, the ship was discernible from miles off. You can also use it to describe something you sense or understand: When your younger brother told he was sorry he broke your baseball bat, the truth was discernible in his voice.
perceptible by the senses or intellect“things happen in the earth and sky with no
discernible cause”“the newspaper reports no
discernible progress in the negotiations”“the skyline is easily
discernible even at a distance of several miles”
capable of being seen or noticed
capable of being perceived clearly“an essay with a meaning that was not always
capable of being perceived by the mind or senses