[The Swiss ball] also gives you more bang for your buck with the added instability, writes Maryniak in an Instagram post featuring the moves. The instability forces your core to work in overtime to prevent your body from toppling over to the side.
Grab a Swiss ball and give Maryniaks top three exercises for hamstring isolation and core demolition a try: the single-leg hamstring curl, the hamstring curl, and the single leg bridge.
For the single leg hamstring curl, start on your back. Straighten both legs, resting the back of your calves and heels on the ball. Engage your core and position your palms flat on the floor. Then, lift your hips and pelvis off the ground until theres a straight line from heel to head. Draw your right knee in towards your chest so that only your left lower-leg is on the ball. This is your starting position.
Next, bend the knee of your working leg, and use your hamstring to pull the ball in towards your rear. You should feel this in your left hammy and glute. Keeping a neutral spine, control the ball back to start by straightening your leg. Thats one rep. Do as many reps as desiredwe recommend 8 to 12before switching legs.
The goal here is to move with the same control as Maryniak. Squeezing your glutes, keeping your eyes on a fixed point, and midline engaged can help. Because its a full body exercise, you may tucker out more quickly than expected. Only do as many reps as you can without sinking into your lower back. If single-leg is too much for you, build-up strength with the double leg hamstring curl before graduating to the single-leg iteration.
The setup for the double-leg hamstring curl is similar. But instead of lifting one leg into the air, youll keep both heels on the ball. Then, with both feet flexed and knees bent, use both hamstrings to draw the ball in towards your body.
Next up: the single-leg glute bridge. This move allows you to strengthen your glutes while hulking your hamstrings. Begin on your back, with your left leg in the air, just as Maryniaks is in the video. With your right knee bent at a 90-degree angle, place your right heel on the ball. Tighten your core, making sure to avoid arching your back. Raise your torso only as high as you can by squeezing your glutes. Slowly lower back down to start position. Thats one rep. Repeat for target number of reps before switching lead legs.