Overuse injuries and proprioception: Mark Alexander argues that reduced joint position sense may hold the key to the understanding and effective treatment of many overuse injuries

What are the main causes of lower limb overuse injuries? Poor biomechanics, inflexibility, weakness and instability are all commonly cited. Rarely will you find a mention of proprioception, but this article argues that this factor is an extremely important component in the development of overuse injuries, which needs to be addressed in injury rehabilitation to prevent recurrences.

Proprioception is the ‘accuracy of joint position sense or the threshold for detecting joint movement’ ⁽¹⁾. Numerous studies have shown that joint sprains of the ankle and knee can cause a reduction in lower limb proprioception and that proprioceptive training can improve joint position sense and hence reduce the incidence of sprains. Yet amid this consensus, the literature is almost silent on the concept of proprioception in relation to the development and subsequent management of overuse injuries. I searched the Pubmed, Medline, Cinahl, Sports Discus, Pedro and Cochrane databases, and found no anecdotal discussions and only one experimental study specifically investigating the effect of proprioception on the development or treatment of overuse injuries of the leg: Baker et al⁽²⁾ showed that individuals with patellofemoral pain syndrome (PFPS) had reduced proprioception.

To date, no relationship has been shown to link proprioception and the development of other lower-limb overuse injuries such as shin splints, stress fractures, ITB friction syndrome and tendinopathies. But it is my belief that proprioception needs to be routinely included in the assessment and treatment of these conditions. If an individual sprains an ankle or knee it has been shown that they are at increased risk of suffering another joint sprain. But if an individual sprains an ankle or knee, are they also at increased risk of developing a lower limb overuse injury? And when an individual presents to the clinic with an overuse injury of the leg, is proprioception routinely assessed, as it would be with joint sprains?

Proprioceptor interference

When ligament fibres are torn, de-afferentation of the joint mechano-receptors adversely alters the spinal reflex pathways to the motor nerves and muscle spindles, as well as to the cortical pathways for conscious and unconscious appreciation of proprioception⁽³⁾. The feedback and feed-forward neuromuscular control systems need these pathways in order to dynamically stabilise joints. The feed-forward motor control system is responsible for the preparatory muscle activity that is vital in maintaining stability and preventing the development of pain in the lumbar spine (Hodges et al, 1997)⁽⁴⁾, patellofemoral joint (Cowan et al, 2002)⁽⁵⁾ and shoulder (Wadsworth & Bullock-Saxton, 1997)⁽⁶⁾. Injury that impacts on this system reduces joint position sense, and joint stability is inherently altered.

Neurology may offer a hypothesis for this. It is common in neurological conditions such as stroke or head injury to see the affected individual compensating for their lack of joint position sense and stability by overshooting and undershooting on motor tasks as a way of increasing feedback to the joint and limb. To extrapolate from this phenomenon, we have all observed how an athlete with a sprained joint will, when standing on the injured side, experience under- and over-shooting movement at the ankle joint and through the whole leg. There is also obvious excessive muscular activity of the ankle stabilisers such as tibialis posterior and the peroneals.

If an individual can’t stand on one foot at rest without excessive ankle and leg sway, then they are clearly going to experience too much uncontrolled foot and ankle movement while running, when the foot strikes the ground. This can lead to overactive shin muscles, such as within tibialis posterior, which can cause excessive pulling of the muscle and lead to shin symptoms.

An analogy I give to patients about how lower limb injuries may develop is to think of the movement of the legs during running as pistons moving vertically up and down within an engine. If the pistons were to become malaligned, the engine could not run properly: the pistons would create friction at certain points, and then break down. Similarly, when a lower-limb joint sprain occurs and malalignment follows in the lower-limb kinetic chain as a result of reduced proprioception, the potential for the development of overuse injuries and muscle strains increases dramatically. The shift in loading and stresses exceed the ability of lower-limb structures to withstand those forces, and microtrauma and pathology ensue.

Adequate shock-absorption, through the control of the leg muscles during running, is an extremely important factor in the prevention of injuries: 60% of generated force is absorbed by the ankle complex and 40% is transmitted proximally (Cook et al, 2000)⁽⁷⁾. If there is inadequate control at the ankle joint with extraneous movement, then the shock generally absorbed by the muscular contraction around the ankle may be transmitted to the other lower-limb structures – a process that may be amplified once the athlete is fatigued.

In future, when athletes with overuse injuries present to the clinic, initially assess their proprioception and train them accordingly, as improvements in lower-limb proprioception can help reduce overuse injuries (Alexander, 2000)⁽⁸⁾. The case study on p2 opposite shows how a proprioceptive deficit led to the development of shin splints, subsequently alleviated by balance and stability training.

CASE STUDY

Patient history

A 30-year-old male triathlete presents to the clinic with a three-month history of right medial shin pain felt with running, which is progressively getting worse. His training has remained constant over the past six months, running 30-40km per week, cycling 150-175km and swimming 15km. He has reasonable running shoes and wears orthotics that are still only six months old and feel comfortable. The only subjective point of note is that he suffered a severe right ankle sprain four to five months ago and despite undergoing physiotherapy treatment on the ankle range of movement and muscle strength after the initial injury, he still feels vulnerable on unsteady ground when he runs. He has been reviewed by a sports physician, who ordered bone scans that returned a normal result.

Physical assessment

This highlighted the following factors:

• good lower-limb biomechanics with walking and running
• poor proprioception and control on right side with single leg squat test, single leg balance test (eyes open and closed)
• ankle dorsiflexion right = left, no limitations
• ender on palpation of the distal mid sections of the medial tibial border. No oedema detected on the periosteum which could signify a stress reaction/fracture.

Diagnosis

The diagnosis was medial tibial periostitis caused by reduced joint position sense or proprioception on his right side after sustaining a right ankle sprain. A hypothesis as to the potential predisposing factors leading to the injury could be:

• previous right ankle sprains leading to
• poor propriception leading to
• poor lower limb stability leading to
• overactive tibialis posterior leading to
• periosteal traction leading to
• microtrauma leading to
• inflammation/injury.

Treatment

Symptomatic treatment consisted of:

• deep tissue massage and acupuncture to the tibial posterior muscle
• once daily oral anti-inflammatory medication prescribed by GP
• topical application of anti-inflammatory gel to tender injured area
• application of ice for 20 minutes daily and after running.

Essential rectification of his predisposing factors included twice daily:

• proprioceptive training of right lower limb (wobble board / single leg balance)
• stability training with single leg squats in front of mirror.

Training modifications

• no running for two weeks
• maintain cycling and swimming mileage
• after two weeks, he resumed running every third day, increasing 1km each session from a 2km starting point, ensuring that he remained symptom-free
• after five weeks he was back to full intensity training with no symptoms.

He still had poorer balance and stability on the right leg than on the left, but the deficit had significantly reduced. He was encouraged to continue his proprioceptive programme to prevent a likely recurrence of injury.

References

1. Ashton-Miller J, Woijtys E, Huston L, Fry-Welch D (2001): Can proprioception really be improved by exercises? Knee Surg Sports Traumatol Arthrosc. 9 (3): 128-136
2. Baker V, Bennell K, Stillman B, Cowan S, Crossley K. (2002): Abnormal knee joint position sense in individuals with patellofemoral pain syndrome. J Orthop Res. Mar;20(2):208-14
3. Swanik C, Lephart S, Giannantonio F (1997): Re-establishing proprioception and neuromuscular control in the ACL-injured athlete. Journal of Sport Rehabilitation May;182-206
4. Hodges P et al (1997): Contraction of the abdominal muscles associated with movements of the lower limb. Phys Ther. 77(2):132-142
5. Cowan SM, Hodges PW, Bennell KL, Crossley KM (2002). Altered vastii recruitment when people with patellofemoral pain syndrome complete a postural task. Arch Phys Med Rehabil. Jul;83(7):989-95
6. Wadsworth D & Bullock-Saxton J (1997): Recruitment patterns of the scapular rotator muscles in freestyle swimmers with subacromial impingement. Int J Sports Med. Nov;18(8):618-24
7. Cook J et al (2000): Patellar Tendinopathy – new approaches to a chronic problem. Phys. SportsMed. 28(6):31-46
8. Alexander M (2000): A Reduction in the Incidence of Injuries in Pre-Season Rugby League Training after the Introduction of an Injury Prevention Program. Sixth International Physiotherapy Congress Proceedings