Exercises that are most effective in improving core strength include the plank, dead bug, and Russian twists. The plank engages multiple muscle groups and builds endurance for the core. The dead bug focuses on coordination and stability, while Russian twists strengthen the obliques. Incorporating these exercises into a routine challenges the core muscles from various angles, promoting balanced strength. It's also beneficial to include functional movements that require core engagement, such as squats and lunges, enhancing overall fitness and athletic performance.