Leg presses are a great way to increase the strength and muscle tone in your legs regardless if you use a leg press machine or free weights. As with any exercise, however, there is a small risk of injury while lifting weights that could occur anywhere in your body. Injuries that result in your core or torso, such as near your rib cage, can be debilitating and painful, if left untreated.
One possible cause of pain near or around your left rib cage is the development of an exercise-induced hernia. A hernia occurs when part of the intestines protrudes through a soft or weak spot in your abdominal wall, often causing a small lump in your side that is accompanied by pain. At times, this pain can radiate throughout one side of your body, and it can feel like you have injured your rib cage. Most hernias can also be made worse during physical activity, such as a leg press, or other strenuous activity.
Another possible cause for pain under your left rib cage is spleen irritation. In most cases, irritation around or within your spleen is caused by intestinal or digestive gases being pushed upward through your digestive tract in the process of exercise or similar physical activity. At times, this gas can cause an increase in pressure in areas of your torso, including just below your rib cage on either side of your body. This pressure can often be painful or made worse with continued activity or stress to your core muscles.
Pain in your left side near your rib cage can also be a sign of a “side stitch," or exercise-related transient abdominal pain. This condition is caused by a spasm in your diaphragm during exercise or physical activity such as running, walking or lifting heavy weights with your legs. When you inhale, your lungs are filled with air and your diaphragm is forced downward in your torso. When exercising and not properly breathing or holding your breath, your diaphragm and abdominal muscles may become cramped. This cramping can cause a sudden sharp pain in your side.
While leg presses focus most stress and activity to your lower extremities, your entire body is required to lift a heavy weight. As such, you may feel pain or discomfort in other areas of your body even when completing a simple leg exercise. If you begin to feel extreme pain in any part of your body, stop exercising immediately and seek medical attention.