Knee trouble could mean you suffer from weakness, imbalance, immobility, or a combination of all of the above. Learning to use full range of motion on leg exercises could be a good first step, along with ensuring the muscles of the posterior chain are making their fair contribution to the leg’s function. Basketball is a sport involving starts, stops, and lots of jumping, so to zero in on the knee joint specifically, it’s good to look at the quads a little closer and make sure they’re firing on all levels. Try these moves:
The Peterson step-up is a move designed to allow the knee to travel far over the toe and bear load using bodyweight as the resistance. Focusing on letting the muscles surrounding the knee (especially the vastus medialis oblique, your “teardrop” quad muscle beside the kneecap) fire strongly to make the movement stable is the key. Start with a box no more than a foot high. To progress this, don’t add weight — just use a higher box.
Terminal Knee Extension
Similar to the Peterson step-up, the terminal knee extension allows the VMO to get some special attention and do its job as a knee stabilizer. Be sure to stand squarely, but don't allow your hips to shift or twist — the only part that should be in motion is the knee joint. Press through the ball of the foot.