A one-leg pike on the yoga ball begins with you assuming a plank position, placing your hands on the ground and your shins or feet resting on the ball behind you. Lift one foot off the ball and extend your leg straight behind you. Engage your core muscles to stabilize your body. Then, while maintaining the plank position, use your foot on the ball to roll it towards your hands by lifting your hips towards the ceiling and bending at the waist, aiming to bring your body into an inverted V shape. Hold this piked position briefly, feeling the stretch in your hamstrings and the engagement in your core. Slowly return to the starting position by rolling the ball back out to the plank position. Repeat for the desired number of repetitions, then switch legs. This exercise targets the core, shoulders, and hamstrings while also improving balance and stability.