Floor bridges target your glutes, hamstrings, and abs while placing minimal pressure on the knees and hips.
How to do it: Lie faceup with knees bent, hip-width apart, feet flexed (pull toes up towards shins and off the floor), and arms by your sides. Brace your abs in and press down through your heels to lift hips up (avoid overarching your back), squeezing through your glutes. Hold for 1 count and then lower hips to floor. Try up to 3 sets of 15 reps.