Pistol Squats with support can effectively strengthen your thighs and glutes.
A challenging exercise that saves you a lot of time, because it effectively strengthens your stomach, chest and sagging arms in one repetition. Of course, you will also use your front core very nicely.
If the exercise is too difficult for you, then move the seat under your knees and hold your body on straight arms (do not do the push up). Exhale when you pull your knees to your chest.