Running and Dorsi Flexor Strength
When a runner has weak dorsi flexors they will have a tendency to slap the ground with every foot strike. A runner slaps the ground because they are unable to control foot motion as they hit the ground (eccentric contraction). Next time you are out running, listen to the runners around you. You will be surprised to hear just how many of those runners are slapping the ground with their feet. These runners are susceptible to shin splints (MTSS).
Another point to consider is that slow runners have a tendency to slap the ground more. In other words, they have weak dorsi flexors. This is a very interesting observation seeing that faster/elite runners are hitting the ground with more force, yet the fast runner is a quieter runner. This is because most elite runners have strong dorsi flexor muscles which are able to control the foot as it comes down. Essentially they have good shock absorbers that are able to dissipate the impact of each stride.
Some of quietest elite runners you will see (actually not hear) are the east Africans. Many of these runners have extremely strong dorsi flexor muscles from running barefoot throughout their lives. Having strong dorsi flexors may be one of the factors as to why east Africans have dominated major marathons around the world for decades. When I ran the Paris Marathon in 2009, the winner was Tadesse Tola from Ethiopia in a time of 2 hours, 6 minutes and 40 seconds. Seeing runners maintaining such incredible speeds while quietly taking each stride is incredible.
A runner at this level recycles about half their energy through elastic recoil. This process is very similar to a spring mechanism, loading and releasing the spring with each stride. Part of this amazing spring mechanism is the dorsi flexor muscles.
Treatment of Shin Splints (MTSS)
The classic treatment of shins splints involves: rest, icing, elevation, compression and some easy stretches. This is good advice especially in the acute stage of the injury. However, exclusively following this advice will not prevent the return of the problem.
In order to resolve MTSS, the removal of any myofasial restrictions that may have formed in the soft tissue is required. This will be done in combination with a program of functional strengthening exercises for both the dorsi flexors and other areas that are affecting gait stability.
Any type of restriction that forms in the dorsi flexors, or other related areas should be removed for a full resolution of shin splints. Some of these restrictions can be removed through the process of self-myofascial release (foam rollers, and stretching). If the restrictions are severe, a manual therapy practitioner (ART, Graston, Massage) will be needed to break the restrictions.
Any time a restriction is removed from one muscle the antagonistic and synergist muscles must also be assessed for restrictions. This is a key point that many manual therapists fail to recognize. For a full resolution, myofascial adhesions must be removed from the entire kinetic chain.
The following list of dorsi flexor muscles are common sites of adhesion removal, but a much larger kinetic chain must also be assessed and treated if necessary.
Dorsi Flexors (Primary)
- Tibialis Anterior Muscle (TA)
- The TA dorsiflexes and inverts the foot. In running, the TA is twice as active as many of the other muscles in the lower extremity. Consequently it is easily fatigued if weak. Once fatigue sets in, abnormal pronation is likely to increase.
- Extensor Hallucis Longus Muscle (EHL)
- Extensor Digitorum Longus Muscle (EDL)
- The EDL dorsiflexes the foot.
- Peroneus Tertius
In Part Four of Shin Splints we will cover: Exercise and Shin Splints.
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