The peroneals are a group of muscles found in the lower leg bone or fibular, which is why they are also often referred to as the fibular or fibularis muscles. There are three muscles in this group: the peroneus longus, brevis and tertius.
Supporting the movement of the foot, these muscles can be subject to overuse, leading to peroneal tendinopathy – pain and swelling in the peroneal tendons.
The origination and insertion of the peroneal muscles
Originating from the fibula, the peroneal muscles become tendons at the lower part of the leg and insert into the metatarsals, which are located between the ankle and toe bones.
The peroneus longus originates at the head of the fibula and inserts into the first metatarsal and the medial cuneiform bone, while the peroneus brevis originates lower down on the fibula and inserts into the base of the fifth metatarsal. The peroneus tertius originates at the back of the third quarter of the fibula and inserts into the shaft and base of the fifth metatarsal.
The action and basic functional movement of the peroneals
The muscle group helps the foot to move, in particular around the ankle joint, and supports us when we stand, whether on both legs or one.
Both the peroneus longus and brevis allow the foot to bend downwards and twist outwards. Additionally, the peroneus longus supports the longitudinal and transverse arches of the foot.
The peroneus tertius is a small muscle that can vary in size and is absent in some people. It lifts the foot upwards and twists it outwards.
What is peroneal tendinopathy?
This is when the peroneal muscles have been overused, causing symptoms such as a painful ache or swelling on the outside of the ankle. You may also feel pain when pointing the foot, moving it inwards or outwards, or pushing off the ball of the foot while walking or running.
It’s common among athletes and sports professionals, in particular runners (especially long distance), dancers and basketball players, as well as any individual who has weak ankles or has suffered an injury to the ankle, such as a sprain.
How is peroneal tendinopathy treated?
Early diagnosis is important and the first stage of treatment is rest. Continuing to walk or run will only make the condition worse. It’s then advisable to consult a physical therapist.
A physical therapist can help you by:
- Assessing your posture, ankle strength, foot mobility and footwear
- Asking about your regular activities that involve specific motion (job, hobbies, sports)
- Establishing which movements you should avoid while the tendons heal
- Recommending treatments such as ice packs or ultrasound
- Using manual therapy to increase mobility in the areas around the injury
- Recommending exercises that stretch and strengthen the ankle, foot and leg to improve mobility and stability, including preventative measures
- Advising on the best footwear for you, including orthotics, eg. shoe inserts, if required
Other treatments that can help include swimming, which will strengthen the ankle without putting weight on it. After a period of time, you can gradually build up to walking and running faster and for longer.
How can peroneal tendinopathy be prevented?
Wearing the correct supportive footwear for everyday and sporting use can help to prevent this condition. In some cases you may benefit from using orthotics.
Specific exercises to strengthen these muscles can also help.
Exercises to strengthen the peroneals
- Standing calf raises – either with feet flat on the floor or standing with the toes on the edge of a step
- Resistance bands – loop under the arch of the foot and flex the foot to strengthen the muscles
- Lunges on to a half balance ball or wobble balance board
- Heel walks
If you are suffering from peroneal tendinopathy, it’s advisable to consult a medical professional and a personal trainer or fitness instructor before undertaking strengthening exercises.