Foot orthoses, which are normally insoles combined with a small wedge-like piece of material called a 'wedge' or 'post' have been part of the sports medicine armoury for years as a method of combating biomechanical imbalances. Recently though, some scientists have questioned whether certain injuries might not be better tackled through core stability exercises.
The debate is whether wedges truly address the cause of the problem or whether they simply deal with one of its symptoms. A problem in the foot, after all, can have its origins in a different part of the body entirely.
"Biomechanically speaking, the foot is merely the end of a series of linkages that make up the human body," says Professor Mark Batt of the Centre for Sports & Exercise Medicine at the University of Nottingham. "So if you have a weakness in, for example, the buttock muscles, it can in turn lead to a problem in the knee which could cause another effect in the foot."
The case against wedges
The argument against wedges, then, is that you're better off working on strengthening or correcting your biomechanical 'foundation' - that is your hips, trunk and shoulders - than forking out for wedges. Too often though, the solution isn't necessarily black or white, according to Batt.
"The principle of using core stability exercises rather than wedges to tackle these kinds of problems is sound," said Batt. "But there will be people, and not necessarily a minority, for whom those exercises will not be sufficient and who will still require orthoses. The key is to get a correct diagnosis - too often othoses are prescribed when they'll do little good." For example, wedges are often prescribed for cyclists to treat front or rearfoot mal-alignments. That is, when one foot is angled inwards or flattened to compensate for a slight difference in leg length. However, according to biomechanics expert Martin Haines, it may not be that the legs are actually of different length, but that they look like they are because of a problem in the alignment of the pelvis.
"A rotated pelvis is probably the most likely reason for people who have one leg shorter than the other," said Haines. "Certainly anecdotal evidence points to this and in these cases wedges can cause more problems than they solve."
A rotated pelvis occurs when the pelvic bone becomes locked in an abnormal position. This rotation results in the apparent leg discrepancy, which the cyclist then tries to compensate for by flattening or arching their foot as they push the pedal, resulting in injury.
In this scenario, Haines argues, wedges may exacerbate the injury as they are likely to perpetuate a leg discrepancy which isn't actually there. Far better, he claims, is to try and correct the pelvic problem through manipulation and exercise.
As a result, Haines helped form a company called HumanLab, which produces a software package that cyclists can use to monitor their own biomechanical health and prescribes correcting exercises accordingly.
They tested 4,000 individuals and compared them bio-mechanically with a couple of computer robots. By seeing how the humans differed from the robot gold standard, they were able to discover the most common problems and the exercises required to put them right.
"There is nothing new about these exercises," said Haines. "They're all established core stability exercises: mostly abdominal and lower-back strengthening work aimed at straightening the alignment of the hips, spine and shoulders. But thousands of people have tried them and have had positive results."
One of those was former Cycling Plus writer Andy Waterman, an experienced cyclist who was perpetually troubled by hip stiffness, especially after long rides. He found that doing the exercises cleared up his problems in a matter of weeks.
Furthermore, while Haines' has a vested interest, even those in the orthotics industry concede that cyclists sometimes need to look beyond wedges for their injury solutions.
"Because cycling is only a semi-weightbearing activity unlike, for example running, and because cyclists only have their fore-foot on the pedal, I think that under these circumstances there is only a limited amount (that wedges) can achieve," said Mark Elmer of Premier Orthotics.
The case for wedges
This is not to say, however, that wedges are useless. There are other causes aside from a rotated pelvis for both leg discrepancy and poor foot alignment. It could simply be a genetic issue or as a result of the healing process following a broken leg. In these cases and others, wedges may still be beneficial either as a stand-alone treatment or in conjunction with the core stability exercises.
For example, Elmer notes that wedges may be of far more use to cyclists off the bike than on because a person is less weight-bearing on a bike than when simply walking around. Plus if it's a heel problem, that part of the foot is unlikely to be on the pedal so a wedge may be of more use on a day-to-day basis, for walking around, than whilst cycling.
"There is undoubtedly a large number of people who do benefit and will continue to benefit from orthotics," said Dr Mike Stone of the English Institute of Sport. "But I think it is fair to say that the number is smaller in cycling than other sports and that the majority of those might be solved through specific exercise programmes."
All the doctors and scientists agreed that the vital first step for any cyclist with a lower-limb injury is to get the problem properly diagnosed. Whether wedges are then part of the correct solution depends on what that diagnosis is, but if the problem is caused by a rotated pelvis, they probably aren't.