The Achilles tendon connects calf muscles to the back of the ankle. It is not difficult to strain this tendon, especially over time, and it can eventually end up with mild swelling or lumps in it.
Lumps in the Achilles tendon may indicate chronic Achilles tendonitis. This is an advanced form of tendonitis that results if the earlier stages of acute tendonitis are not properly treated.
Achilles tendinitis comes about from overuse of the tendon, either by suddenly increasing activity, not allowing enough downtime between activities or overusing weak calf muscles, per Mayo Clinic. Running uphill or on feet that turn inwards, or overpronate, can also lead to tendinitis.
Shoe type can also play a part in tendinitis that leads to nodules or lumps. High heels shorten the Achilles tendons, which may then be overexerted in flat shoes, and a change in workout shoes may also contribute.
A cold pack coupled with resting the tendon helps alleviate the condition, as does wearing a heel pad while the tendon is healing.
A specialists may be needed for proper treatment; they may recommend anti-inflammatory medications, taping the leg to support the tendon or even applying a cast. Surgery, sports massages, ultrasound treatments or orthotics, which are supportive insoles, may also be suggested.