Arms are connected to each other, and research as shown that individuals who continued to work their good arm still increased strength in the injured limb, despite not actively working on it. This is because muscle fibers are connected between the limbs.Mengenix Muscle Rampage Have you ever heard that you can jog and that's all you need to build up your stamina when you exercise? Start slowly. Then, week by week increase your jogging time. Make an effort to keep your heart rate at around 75% of your top limit. This often averages out somewhere between 120 and 150 beats per minute, but it can vary with age.Mengenix Muscle Rampage A great fitness tip for those people trying to get fit and build strength is lifting lighter weights at faster speeds.