Several reasons that could cause a person to walk on one leg include a fracture, recent surgery or an amputation. Regardless of the reason, one leg is not accustomed to carrying all your upper body's weight, so muscle soreness is to be expected. Consult with your doctor if the soreness does not disappear within a week or the pain gets worse.
Identification
Everyone experiences muscle aches occasionally. Pain can occur in any one of your leg muscles and can affect your ligaments and tendons. Muscle aches often have a dull, persistent pain that may have a slight burning sensation. If you've strained your leg muscles, it may be difficult to fully extend your knee. The muscle may also be swollen and have spasms. If your condition is because of a recent event, you may experience delayed onset muscle soreness, or DOMS. DOMS will make the muscle feel tight and sore. The pain starts going away within three days and is usually gone within a week.
Cause
Muscle aches and strains are overuse injuries. Extra weight placed on your good leg will make the muscles work harder than they're accustomed to and this will result in the aching sensation. If your muscles are tight or weak, they must adjust to the new usage. Repetitive movements over a prolonged period cause muscle strains. DOMS is normally associated with exercise, but hopping -- a common action if you're only walking on one leg --- increases your risk of DOMS. The exact cause of DOMS is unknown, but it occurs when you overload your muscles, which results in microscopic muscle tears. If you've exercised beyond what your body is accustomed to, you'll usually notice DOMS in your muscles within 24 hours.
Treatment
Muscle aches and DOMS can be treated at home by resting your leg and taking over-the-counter pain medication to relieve soreness. Ice the area four times per day for 15 minutes during the first 72 hours. If you continue to experience muscle aches, heat the area after 72 hours. Massaging and gently stretching your muscles can also give you relief. A strain can be treated the same way, except you'll want to compress the muscle with a wrap and elevate it above your heart to reduce swelling.
Prevention
Since one leg is carrying all your upper-body weight, you'll want to keep it flexible and strengthened. Stretch your leg several times per day, paying extra attention to the calves, hamstrings and quadriceps. Swimming and water aerobics are non-weight-bearing aerobic activities that help you strengthen your leg with water resistance. Wear supportive shoes to reduce your risk of falls and support your ankle. Once DOMS occurs in your leg muscles, you're unlikely to experience it again until you increase the intensity of physical exertion on your leg.
