Practical Research Finding Implementation and Experimentation Stage -- Phase I
The experimenter did not set out to determine specifically which of the various contributing factors (or combinations of factors) identified by the empirical research of medial tibial stress syndrome was most responsible for the experimenter's symptoms. However, since the initial attempts to resolve the symptoms incorporated changes to all of the external variables except a change in running surface, the experimenter immediately sought a softer running surface and temporarily abandoned running on any hard surface that magnified instead of minimized the physiological trauma associated with running on harder surfaces.
Because the empirical research also implicated poor running stride mechanics and excessive vertical elevation, the experimenter devoted considerable attention to making the following specific changes to the running stride: (1) shorter strides to minimize travel of the body while neither foot is in contact with the running surface; (2) conscious attempts to reduce vertical clearance to a minimum; and (3) increased surface contact of the sole and the running surface in a manner designed to decrease the magnitude of the highest spike in compressive load transmitted from the foot to the tibia on each foot-fall.
To reduce the risk of other injuries, such as ankle sprains, from uneven natural grass surfaces, the experimenter found an asphalt outdoor running track that was surrounded by a well-manicured grass field suitable for running on a soft but extremely uniform surface.
Unfortunately, none of these changes made a significant difference. Even the substitution of a much more forgiving natural running surface only further delayed the initial onset of symptoms and the increase of their intensity. However, the changes implemented by the experimenter were insufficient to allow the pursuit of running as a regular fitness activity because even with all of the changes implemented for the purpose of addressing the shin splint issues the symptoms recurred too soon and too intensely not to interfere with the activity.
As a last resort, the experimenter decided to try another anecdotal suggestion; namely, to try brisk walking or "power walking" on inclined surfaces such as naturally hilly terrain instead of running on flat surfaces. In principle, the idea is that brisk uphill walking provides many of the same cardiovascular and other physiological benefits of running, but eliminates the excessive trauma associated with the relatively high impact of foot-fall during a running stride.
A running stride necessitates that the exerciser leave the ground entirely and therefore, the high-impact nature of the activity cannot be eliminated entirely, even with perfect running stride mechanics; it can only be reduced. Conversely, a walking stride allows one foot to remain in contact with the surface at all times, and never requires that either limb bear the entire weight of the body without support from the opposite limb. It also dramatically reduces the mechanical loading and the intensity of the compression load spike associated with a running stride where each foot (and tibia) must bear the mechanical equivalent of several times the body weight on each stride (AOS, 2007; NIH, 2009).
However, the experimenter found that the symptoms actually increased from power walking on an inclined surface instead of decreasing.
As a result, the experimenter initiated additional searches for empirical research to identify additional possible solutions and to consider the possibility that the symptoms could be associated with alternate diagnoses. In fact, the experimenter managed to identify another major potential source of explanation for the physiological symptoms that related to a completely different aspect of physiology and biomechanics: Exertion-related Compartment Syndrome of the tibial fascia.
Survey of Empirical Research on Exertion-related Compartment Syndrome
Apparently, shin splints are frequently misdiagnosed because of the relative similarity in symptoms with another condition that is the result of entirely different physiological issues (Braver, 2002). According to the scientific literature, a system of muscles in the lateral anterior region of the tibia is responsible for the motion that allows the raising of the foot from the neutral position. Without these muscles, it would be impossible to walk or run efficiently because the foot would remain in the extended position at the end of each stride (Schissel & Godwin, 1999).
Like other muscles, the muscles in the anterior lateral region of the shin expand substantially during physical exercise as the result of engorgement with blood required to oxygenate those tissues and remove the buildup of lactic acid and other waste products produced in the physiological processes involved in repetitive muscular contraction during physical exertion (Mohler, Styf, Pedowitz, et al., 1997).
Also, much like other muscle systems, the set of muscles in the anterior lateral region of the tibia are bound together and encased in a compartment composed of a thin fibrous tissue sheath through which the muscles slide back and forth during physical exertion. In some individuals, there is insufficient room to accommodate the temporary increase in muscle volume associated with their increased size by virtue of engorgement with oxygenating blood volumes (Howard, Mohtadi, & Wiley, 2000; Mohler, Styf, Pedowitz, et al., 1997).
Because the biomechanical causes of shin splints and exertion-related compartment syndrome (ECS) are entirely different, the appropriate methods of reducing the factors responsible for the two conditions also differ tremendously. Whereas the symptoms associated with shin splints are most likely to respond to changes in exercise that reduces the exposure of the tibia to direct compressive loads and high impact under the weight of the athlete, the symptoms associated with ECS are most likely to respond to entirely different types of exercise adjustment and therapeutic modalities (Braver, 2002).
Moreover, ECS is not exclusively related to the tibial region as is generally the case with stress fractures, simply because other bones of the human anatomy are comparatively unlikely to be exposed to the types of repetitive impact and compressive loading in the manner that the running stride stresses the tibia. Stress fractures in the upper extremities, for example, are most often seen in laborers who use impact tools such as hammers and pneumatically powered mechanical equipment that transmit the mimetic forces of repetitive impact and/or vibrations to the user (Wilder & Sethi, 2004).
Exertion-related compartment syndrome is also commonly experienced by those who use their forearms in a manner that requires extended repetitive contractions, such as laborers who use hand tools, particularly those that require continual rotational exertion without the benefit of electrical or pneumatic assistance (Wilder & Sethi, 2004). In principle, the physiological phenomenon responsible is identical regardless of which particular group of muscles is involved: in all cases of ECS, the affected muscles become engorged with blood during the re-oxygenation and waste product removal process of repeated muscular contractions. Wherever the compartment formed by the fascia sheath surrounding those muscles provides insufficient space to accommodate the temporarily engorged muscle tissue, the resulting pressure causes considerable pain that is only capable of being reduced by cessation of the muscular contractions responsible for it (Mohler, Styf, Pedowitz, et al., 1997; Schissel & Godwin, 1999).
According to the literature, the fact that power walking up an incline surface dramatically increased the symptoms is a principal distinction between shin splints and ECS-related symptoms (Barver, 2002). Where symptoms are the result of shin splints, the substitution of brisk walking nearly always eliminates them, except where substantial inflammation still exists from previous exercise. However, unlike the symptoms associated with shin splints, the symptoms associated with ECS generally dissipate more quickly and are less likely to persist more than a day after the last exercise session.
Furthermore, walking (on a level surface) tends to cause pain where shin splints are involved because the irritation to the bone and/or to the periosteum produces sensitivity for several days following the most recent acute irritation to the area (Braver, 2002). Conversely, the symptoms associated with ECS tend to dissipate after the muscle tissues whose temporary engorgement is responsible for the condition as soon as those tissues return to their normal (i.e. un-engorged) condition (Mohler, Styf, Pedowitz, et al., 1997).
With respect to the differentiation of shin splints from ECS of the anterior tibial compartment is that the former is often associated with considerable tenderness to the touch in the medial in the inside (medial) region of the tibia whereas the latter is generally associated mainly with tenderness in the outside (anterior) portion of the lower leg. In addition, whereas the symptoms of shin splints persist and are often associated with tenderness to the touch several days after the most recent exercise session, the pain associated with ECS is only evident to the touch during and immediately after the exercise activity responsible for the irritation. Finally, as pertains to the differentiation of the two conditions, the symptoms of shin splints are produced by low-impact walking, even brisk walking on an inclined surface. Meanwhile, those associated with ECS in the anterior tibial compartment are dramatically increased by walking up an inclined surface, precisely because this motion exaggerates the range of motion of the…