When I was younger, my main fitness goals revolved around faster runs, heavier lifts, and a leaner physique.Once I turned 40, a few recurring injuries made me realize that I needed to shift my focus. I started to train with longevity in mind, paying more attention to deep core stability, pain-free mobility, optimal range of motion, and functional strength.I began incorporating the following four exercises into my regular routine. These moves target key muscle groups that not only support the pelvis and spine, but also facilitate every day movement and maintain proper posture.If you’re nearing (or over) 40, have a yoga mat and a set of dumbbells handy, and want to preserve your strength as you get older, give these exercises a try.How to do the 4 exercisesConsult with your medical team before starting any new activity. If you’re a beginner, consider meeting with a certified personal trainer to learn proper exercise form. A trainer can also provide modifications when necessary and progress the exercises as needed.You’ll need a yoga mat and a set of moderately-heavy dumbbells for this workout.Start by doing 1-2 sets of the dumbbell front squats, bear plank leg reaches, and renegade rows for 8-10 reps. Hold the side plank for 15-30 seconds. Once your strength improves, gradually increase to 3 sets of 10-12 reps and 30-45 second holds. You can perform these exercises as a circuit and complete one set of each exercise before repeating, or you can perform all sets of a given exercise before moving on to the next.Get instant access to breaking news, the hottest reviews, great deals and helpful tips.If you’re unable to complete at least 8 reps with good form, use a lighter weight. If you can perform 12 reps without feeling fatigued, use a heavier weight.Here’s how to do the exercises:1. Dumbbell front squats