Running on a treadmill offers distinct advantages over running outdoors. The deck is softer than asphalt or concrete, foul weather and high winds are not factors, you can calculate the distance you cover with great precision, and you can bail at any time without needing to find a way back to your starting point. Nevertheless, unilateral aches and pains in the lower leg are common even under these welcoming conditions. Work with your physician to determine the cause of your pain and discuss the best treatment options for your condition.
Achilles Tendinitis
Almost all runners experience Inflammation of an Achilles tendon at some point. It is usually an overuse injury that can be caused or aggravated by running faster than usual or doing a lot of running uphill, both of which stretch the calf beyond its typical range of motion. If you incline the treadmill deck, keep it to less than a 5 percent grade if you've had recent Achilles trouble. A tight calf and worn-out shoes also contribute to the development of this type of tendinitis. Treatment includes ice, anti-inflammatory medication, careful stretching and, in severe cases, corticosteroid injections.
Shin Splints
Shin splints are a common complaint among novice runners and those who have recently upped their training volume. They can strike both shins, but if you have a leg-length discrepancy, pain on the left leg only is not unusual. Worn-out shoes can also set you up for shin splits. The pain often dissipates after you rest for a few days, ice the area twice a day for about 15 minutes, and get new shoes if necessary. Slowing the belt down by one or two miles an hour can help, too.
Posterior Tibial Tendinitis
The posterior tibial tendon on the inside of the ankle is the primary support of the arch of the foot. When overworked, it may become inflamed, as when you boost the speed or amount of your training overzealously. If you have flat feet or overpronate with your left foot -- that is, roll it foot inward as you move from heel to toe -- then you're especially susceptible to this tendinitis. Treatment includes rest, icing, making sure to wear rigid and supportive shoes and possibly an orthotic insert for your left shoe.
Peroneal Tendinitis
This injury resembles posterior tibial tendinitis, but is on the outside of the ankle rather than the inside. It results in a more dull, gradually worsening type of pain than other types of tendinitis. There may be a small lump in the region. Pain is usually worst in your ankle but may extend to the arch of your foot. According to Northcoast Footcare, running in worn-out shoes -- easy to do when you usually run on a bouncy treadmill and are thus less aware of your shoes' cushioning status -- is a common cause of peroneal tendinitis. Treatment includes icing and stretching.
