Doing push ups while pushing her body up and down to strengthen her core, the woman is doing her fitness routine in a gym

push ups upperbody core strength circuit training workout fitness strength workout tightening core chest muscles bending elbows abdominal muscles external obliques internal obliques rectus abdominis muscles deltoids pectoral muscles triceps biceps upper arm gluteal lower back resistance training weight loss burn calories metabolism burn fat pink yoga mat exercising aerobic physical fitness health physical exertion warm up routine keep in shape relaxation physical exercise limber up stretching healthier lifestyle workout regimen conditioning drills stretches lifestyle conditioning rehabilitation gym