Having a strong back and core does a number of positive things for you. First, it makes everyday activities such as doing yardwork, cleaning the house, and playing with the kids or grandkids easier. It also helps protect your spine, which likely means fewer back problems and a higher quality of life. So, which exercises are key to these two areas? Here are the best five:#1: The PlankThe plank works almost every muscle in your body, which is why it is number one on this list. To do it, simply lay face first on the ground with your elbows bent and your upper body weight on your forearms. Now, straighten your body so your weight is balanced between your forearms and your toes and hold this position for 10 seconds. Add a few seconds each time and work your way up to one full minute. #2: Push-UpsAnother exercise that is good for both your back and core is the pushup. Still lying face down, place your palms beneath your shoulders with your elbows bent. Slowly extend your arms until they are almost straight, balancing on your palms and toes before lowering to the start position.#3: Pull-DownsPull-downs work your upper back and your core, strengthening both in the process. To do them, attach a pull-down bar to the weight machine and grasp it with your hands about shoulder width apart. Slowly pull the bar down in front of you, to about chest height, before returning to the starting position.#4: Squat with Knee LiftsTo focus on your lower back and core, start with a squat. Upon returning to a standing position, lift one knee to waist height. Then lower that leg to the floor, do another squat, and perform a knee lift on the other side.#5: Sitting TwistsAnother great exercise for your back and core is the sitting twist. Simply sit with your knees bent, holding a medicine ball in front of you. Slowly, twist your torso while moving the medicine ball to the right. Then twist slowly to the left before returning to the starting position.What exercises do you like to do for your back and core?