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Training smarter, not harder, is the key to longevity as you age. It's a lesson that comes to most of us at some stage, but I wish someone had told me sooner.Working your key major muscle groups several times per week can help counteract the natural loss of muscle mass and strength that occurs through the decades, but there are some muscle groups I really want you to focus on later in life, and those are your glutes, hips, legs and shoulders.Strong glutes help stabilize your pelvis and keep your lower back safe; robust legs will allow you to stay balanced and active; mobile, active shoulders support proper posture and allow you to lift, push and pull your own weight.You don't need to get down on the ground to do these exercises, and for most people, they're low-impact. Give these moves a go, and let me know how you get on in the comments section below.2 moves I recommend as a personal trainerI highly recommend Bulgarian split squats and scapula push-ups as part of a wider exercise routine. Bulgarian split squats strengthen your hips, legs and glutes, while scapula push-ups work the shoulder blades through protraction and retraction, strengthening the stabilizing muscles that support shoulder movement.1. Scapula push-upsDuring scap push-ups, you'll protract and retract the scapulae (shoulder blades). Drawing the shoulders apart is protraction, as you push your chest away from the floor, whereas retraction involves pulling the shoulder blades together and drawing the shoulders back.You’ll start in a push-up position on your toes or knees. Keeping your arms straight, perform a push-up without bending your elbows. You could also perform this against a wall while standing.Get instant access to breaking news, the hottest reviews, great deals and helpful tips.Here's how to do scapula push-ups:Start in a push-up position with your shoulders stacked over your wrists and hips aligned with your shoulders. Use your knees if you preferBrace your shoulders, core, glutes and quadsPress through your hands and slightly rotate your shoulders outward to help engage your backKeep your arms straight, then push your chest away from the floor, pulling your shoulder blades apartPause, then draw your shoulder blades together and lower your chest toward the groundContinue for 8-12 reps and 3-4 sets.