Shin splints in runners: is there a better treatment approach?

The lower leg is densely packed with muscles, each surrounded by a compartment of connective tissue (fascia). Although MTSS can be caused by a dysfunction in a number of these muscles, one popular theory is that tension caused by repeated loading on the boundary between the posterior tibialis muscle and the tibia bone (red shaded area) is the primary cause of pain in MTSS.

Are you at risk of MTSS?

Given that an ounce of prevention is worth a pound of cure, and the fact that following an episode of MTSS, the rate of relapse is high, being able to predict the onset of MTSS and take proactive and pre-emptive action is a valuable asset for athletes and coaches. To date, studies have suggested the following risk factors for MTSS:

·        Excessive pronation of the foot (see figure 2), female gender, and a history of previous shin splints⁽⁸⁾.

·        Flattening of the long arch of the foot (ie in the heel-toe direction), increased plantar flexion in the upper ankle joint (see figure 2), and reduced internal hip rotation (where the leg is rotated inwards towards the midline of the body) ^(9,10).

·        Smoking and poor cardiovascular stamina⁽¹⁾.

·        An increased body weight/mass index⁽¹¹⁾.

Figures 2&3: Pronation and ankle movement (right leg seen from the rear)/Plantar flexion vs. dorsiflexion

Figure 2 (top): Excessive pronation is where the foot rolls inwards too much after footstrike, subjecting the ankle and lower leg to undesirable loading.
Figure 3 (bottom): During running, increased plantar flexion means the shin muscles have to work harder to bring the foot back to a horizontal position.

The above risk factors are undoubtedly useful to be aware of, but are there any tests that can accurately predict the likely onset of MTSS? A large study on Australian military personnel attempted to identify individuals in a pre-symptomatic stage of MTSS (ie those without symptoms but who would likely develop symptoms)⁽¹²⁾. These tests consisted of the shin palpation test and shin oedema test, which together took only around 30 seconds to complete (see box 1 for details).

These results found that both the shin palpitation and the shin odema tests were strongly predictive of future development of MTSS. However, in subjects who scored positive on both tests, the result was extremely predictive. While other physical examinations are still important, this study makes a strong case for inclusion of these quick tests into a coach’s or physio’s preseason musculoskeletal screenings on athletes. They take minimal time to perform, and the findings, combined with the athlete’s sport, and gender could help determine if there is a risk of developing MTSS in the near future, in which case training can be modified to prevent this.

Box 1: Testing to predict MTSS (shin splints)

Test 1: Shin palpation
Moderate pressure is applied to the shin bone, two thirds of the way down and on the inside. A positive test is recorded if there is any pain present.

Test 2 Shin oedema
Pressure is applied constantly for five seconds on the shin bone, two thirds of the way down and on the inside. A positive test is recorded if there is pitting oedema (a dent lasting on th shin once pressure is released).

What are the symptoms of MTSS?

MTSS typically starts with vague, diffuse pain in the lower leg, along the middle to lower portion of the shin bone. The pain is associated with exercise⁽¹³⁾, and in the early stages, pain is worse on starting exercise, gradually subsiding during training or shortly after the end of exercise. However, as the injury progresses, less and less activity is required to produce pain, and eventually pain can occur even at rest.

When athletes develop these symptoms, an assessment is needed from a physio as soon as possible. He/she will need to obtain a comprehensive exercise history including:

·        The athlete’s weekly exercise routine and total training volumes (eg total running mileage).

·        Exercise intensity/pace/loading.

·        Footwear used.

·        Training terrain.

Particular attention needs to be given to any of these factors that have changed radically over the past three months. This is because research suggests that MTSS is most likely to occur in athletes who have attempted to do ‘too much, too fast’^(14,15).

Common errors include a recent onset of rapidly increased activity, intensity, or duration⁽¹⁶⁾. Running on hard or uneven surfaces is also a common risk factor and all risks are increased once weekly mileage exceeds around 20 miles per week⁽¹⁷⁾. Athletes and their coaches should also be aware of the MTSS gender factor; studies indicate that the risk for progression from shin splints to a stress fracture is 1.5 to 3.5 times greater in females than in males^(17,18). This is especially relevant in females at risk of diminished bone density and osteoporosis – commonly observed in the ‘female athlete triad syndrome’ (osteoporosis, amenorrhea, and disordered eating – see figure 4 and this article)⁽¹⁹⁾.

A physical examination is also needed. In this, the physio will check for knee abnormalities, foot arch abnormalities, or a leg-length discrepancy. Abnormal gait patterns should be evaluated with the athlete walking and running, either in the office hallway or on a treadmill. A physio will also check for any symptoms indicating that the cause of pain is not MTSS. For example, symptoms such as sensory or motor loss in association with lower leg pain during exercise can indicate acute a completely different condition known as ‘chronic exertional compartment syndrome’, which is most likely to be confused with MTSS.

Figure 4: The ‘female triad’ spectrum

Rather than an ‘either/or’ condition, the female triad can be considered as spectrum from optimum eating, hormonal function and bone health (green) to poor eating/eating disorder, amenorrhea and osteoporosis at the other end (red). The further towards the red end of the spectrum, the greater the risk of MTSS progressing to a stress fracture.

Treating MTSS

There are a number of conservative treatment options for MTSS, but some are more effective than others⁽⁷⁾. For athletes diagnosed with MTSS, treatment is usually split into an acute phase to allow symptoms to settle, followed by a post-acute phase, during which the goal is to prepare the athlete for a full return to sport.

*Acute phase

In the acute phase of MTSS, rest is essential, with a complete or partial cessation of activity for 2-6 weeks depending on symptom severity⁽²⁰⁾. Non-steroidal anti-inflammatories (eg Ibuprofen) and paracetamol are often used for pain relief, while ice application to the affected area directly after exercise for approximately 15–20 minutes is also recommended.

Given that weeks of complete inactivity in athletes will do nothing for fitness, other treatment modalities to try and speed healing have also been advocated in the acute phase. These include ultrasound, whirlpool baths, soft tissue mobilisation, electrical stimulation, and unweighted ambulation (eg walking in water). However, while these are popular approaches among some clinicians, there’s little evidence that they offer tangible benefits over and above just rest and ice^(3,6,13-15).

*Post-acute phase

·        Training modification - Once the initial symptoms have subsided, the goal is to enable athletes to gradually return to training and competition without a relapse. Without doubt, the most important requirement is to modify the original training program and also address any biomechanical abnormalities. Research indicates that runners can continue to improve without cessation of activity so long as their weekly running distance, frequency, and intensity are reduced by at least 50%. In addition, they should eliminate running on hills and uneven or very firm surfaces, which increase loading on the tibia^(3,13-15). A better option is train on a synthetic track or treadmill, both of which provide a uniform surface with more shock absorption. During the post-acute phase, athletes can benefit from cross training with other low-impact exercises such as pool running, swimming, elliptical trainers or stationary cycling. This is also the time for physios and coaches to work with athletes on proper technique and running gait retraining, helping them to return to activity in a step-wise fashion. Over a period of weeks, training intensity and duration can be gradually increased and jumping exercises and hill running added as long as the athlete remains pain-free⁽³⁾. However, athletes should scale back any exercises that exacerbate their symptoms or cause pain.

·        Footwear - Many studies report that appropriate footwear can reduce the incidence of MTSS^{(3,15, 20,21)}; athletes should therefore switch to shoes with sufficient shock-absorbing soles and insoles, in order to reduce forces through the lower limbs. Runners should also change running shoes every 250–500 miles, a distance at which most shoes lose up to 40% of their shock-absorbing capabilities and overall support^(14,22). In addition, athletes with foot-related biomechanical problems may benefit from orthotics ^(13,14,16). Over-the-counter insoles may be sufficient to help with excessive foot pronation and low foot arch, but problems caused by forefoot or rearfoot abnormalities may require custom orthotics⁽²³⁾.

The role of fascial tissue in MTSS

Some researchers believe that the distortion of fascial tissue (the connective tissue that forms sheathes around muscles) plays an important role in the development of MTSS^(24,25). Targeted manual therapy (massage, mobilization) has been shown to reduce pain and improve function in frozen shoulder^(26,27), which is also related to fascial dysfunction (see this article) so can it help athletes with MTSS?

One study that looked at this question found that when MTSS patients were treated using manual therapy targeting the fascial tissue, there was a significant reduction in pain and an increase in exercise tolerance⁽²⁸⁾. Importantly, this manual therapy for the fascia was showed benefits in a short timescale. The drawback of course is time and cost; regular manual therapy sessions like this take around one hour per leg, which when delivered by a qualified physio is expensive! In addition, little is known about the longer-term benefits – ie whether the reduction of pain is maintained over time and whether the risk of reinjury is reduced.

The latest thinking

The most recent research on shin splints has tended to consolidate and refine what we already know about MTSS, rather than radically change our understanding and treatment approaches. An in-depth review of the all the literature to date was published earlier this year in the journal ‘Cureus’, and it concluded the following⁽²⁹⁾:

*Causes

·        Shin splints are brought on by persistent strain on the connective tissues that attach muscles to the shinbone and usually appear after abrupt changes in physical activity – both in terms of workload and the type of running – eg jogging uphill or for longer distances.

·        Predisposing factors include flat feet or inflexible arches, and exercising in unsuitable or worn-out footwear.

·        Distance running is the activity most likely to precipitate the condition.

*Management

·        The standard course of treatment includes taking several weeks off from the painful activity during which lower-impact exercise such as swimming, stationary biking, elliptical training etc is recommended as a substitute.

·        Acute pain can be managed by anti-inflammatory medications including ibuprofen, aspirin, and naproxen. Ice can also be applied several times a day, and compression bandages may help.

·        Flexibility exercises for the shins may assist in recovery.

·        Shoes with good cushioning and arch support are recommended while orthotics or other inserts may be helpful for those more persistent shin splint issues.

·        At least two pain-free weeks should elapse before running is restarted.

·        Once activity is resumed, exercise should not be performed as frequently or for the same amount of time as it previously was in the past, and a thorough stretch and warm up before exercising is recommended

·        Exercise duration and intensity should be increased only slowly; if pain returns, exercise should cease for two days and cold packs used, then exercise resumed at a lower intensity before the pain reappeared.

In summary

When athletes start to suffer with shin splints (MTSS), they need to understand that although merely inconvenient to begin with, if left untreated, a much more serious stress fracture injury may follow. It’s also important to realize that when MTSS occurs, it signifies that the athlete’s training habits need adjusting – not just in the short term with rest and recuperation, but also in the longer term to prevent reoccurrence.

There is no magic bullet to treat MTSS, but by sticking to the treatment recommendations outlined above, most athletes can expect a steady and complete resolution of the condition – providing of course, training is adjusted appropriately. In addition to rest, the use of anti-inflammatories, icing, and change to footwear/orthotic use, some other therapies to speed recovery may help, although the data for long-term benefits is far from conclusive. The take-home message is that if MTSS strikes, don’t ignore it; the earlier you seek advice,   take proactive action and adjust your training regime, the more rapid and complete your recovery will be!

References

1.       Gait & Posture. 2011;33(3):361–365

2.       Clinics in Sports Medicine. 2012;31(2):273–290

3.       Sports Med. 1998;26(4):265–279

4.       Radiology. 1997;204:177–180

5.       Sports Med. 1986;3(6):436–446

6.       Am J Sports Med. 1995;23:427–481

7.       Curr Rev Musculoskelet Med. 2009 Sep; 2(3): 127–133

8.       MTSS Clin Sports Med. 2012 Apr;31(2):273-90

9.       Journal of Foot and Ankle Surgery. 2008;47(2):89–95

10.     Scandinavian Journal of Medicine and Science in Sports. 2012;22(1):34–39

11.     Journal of Orthopaedic and Sports Physical Therapy. 2007;37(2):40–47

12.     Br J Sports Med. 2012 Sep;46(12):861-4

13.     Med Sci Sports Exerc. 2000;32(3 suppl):S27–S33

14.     Sports Med. 1996;21:49–72

15.     Clin Sports Med. 2004;23:55–81

16.     Phys Med Rehabil Clin N Am. 2006;17(3):537–552

17.     Phys Med Rehabil Clin N Am. 2007;18(3):401–416

18.     J Sports Med Phys Fitness. 1990;30(3):307–315

19.     Am J Sports Med. 2004;32(3):772–780

20.     Phys Sportsmed. 2002;30(6):29–361

21.     Med Sci Sports Exerc. 2002;34(1):32–40

22.     Am J Sports Med. 1985;13:248–253

23.     Med Sci Sports Exerc. 1995;27:800–804

24.     J Am Chiropr Assoc. 2004;41(9):32–42

25.     Journal Am Podiatric Med Assoc. 2007;97(1):31–36

26.     Med Sci Sports Exercise. 2009;41(11):1991–1996

27.     Zeitschrift fur Orthopadie und Unfallchirurgie. 2012;150(4):420–427

28.     Stein C. Untersuchung der Wirksamkeit einer manuellen Behandlungstechnik nach dem Faszien-Distorsions-Modell bei schmerzhaft eingeschränkter Schulterbeweglichkeit - Eine explorativ-prospektive, randomisierte und kontrollierte klinische Studie. Medizinische Hochschule Hannover; 2008

29.   Cureus. 2023 Jan; 15(1): e33905