Crunches

According to Russell, the problem with this commonplace ab move is the curving of the spine and lower back, which can be hard on older bones if they’re not already reinforced with regular exercise. “I would suggest a plank to work the abs instead.”
Check out these beginner-friendly exercises you can do at home right now.
Dead lift

“Dead lifts can put a lot of strain on the hips and torso,” says chiropractor Kelsey Nelson. Instead, she recommends doing body-weight exercises such as glute bridges: lie on your back and bend your knees with your feet flat on the ground; keep your heels close enough that you can touch them with your fingertips. Press your feet into the floor and lift your hips toward the ceiling, then lower them.
Jumping lunges

Plyometric leg exercises include things like jump squats and jumping lunges. “These can cause joint strains as well as wear and tear,” says Nelson. She still likes lunges; she just recommends removing the jumping part – or doing them on a springy floor.