Shoe effects on tibial rotation vary
By Jordana Bieze Foster
Research from the U.K. published this month suggests that motion control running shoe technology can help decrease tibial internal rotation during running, theoretically decreasing the risk of proximal symptoms such as those associated with iliotibial band syndrome or patellofemoral pain syndrome.
However, the study found that the magnitude of change in TIR associated with footwear structure varied considerably within the study population, suggesting that shoe-specific interventions may be more effective for reducing injury risk in some runners than in others. The findings were published in the September issue of Physiotherapy.
Investigators from the University of Brighton analyzed proximal TIR in 24 healthy participants as they ran on a treadmill under two different shoe conditions. All participants were tested first while wearing neutral running shoes, then while wearing motion control shoes designed to limit pronation. The volunteers ran for five minutes to accommodate to the treadmill and shoes prior to each testing session.
For the group overall, TIR was significantly reduced in the motion control shoes compared to the neutral shoes. The mean difference between conditions, although statistically significant, was just 1.38°. However, individual results varied widely, with nine participants experiencing decreases of 3° or more and five participants, surprisingly, experiencing increased TIR (as much as 6°) in the motion control shoe.
Because the order of conditions was not randomized, the authors hypothesized that the increased TIR associated with the motion control shoe might have been the result of fatigue.
“Van Gheluwe and Madsen [in the February 1997 issue of the Journal of Biomechanics] found total pronation on average increased by 1.8° at the end of a treadmill run compared to the start. They concluded that rearfoot motion is directly affected by fatigue. Therefore it could be said that those five runners were tired [due to lack of treadmill experience] and as a result displayed increased pronation and a subsequent increase in tibial rotation,” said Alice Rose, BSc, MCSP, a physiotherapist for the National Health Service in Bristol, U.K., who was involved in the study while a
student at the University of Brighton.
Other variables not accounted for in the study could have played a role, suggested Bruce Williams, DPM, a podiatrist at Breakthrough Podiatry in Merrillville, IN.
“My feeling is that fatigue was of minimal input, but that foot type, ankle dorsiflexion range of motion, and arch height or stiffness were more likely to have caused the differences,” Williams said.
Tracy Dierks, PhD, an associate professor of physical therapy at the Indiana University School of Health & Rehabilitation Sciences in Indianapolis, allowed that fatigue might have been a factor. He also suggested, however, that the findings underscore the fact that the “control” provided by a motion control shoe is relative.
“Just because you have a “motion control” shoe on doesn’t mean it controls motion. Just because you have a laterally wedged orthotic in a shoe doesn’t mean you can’t move the foot laterally. The foot has 28 bones, so it can move pretty freely regardless of the shoe type,” Dierks said.
Given that some study participants did experience significant decreases in TIR with the motion control shoes, further research is needed to identify and characterize that subset of patients, Williams said.
“Ultimately patients do get results with these shoes, but there are many factors to study as to what foot types seem least likely to benefit,” he said.
But the larger take-home message may be that shoes alone will not reduce injury risk in all runners.
“Shoe type can certainly
influence running mechanics, but it isn’t the only thing that can,” Dierks said. “There are many more factors besides shoe type that are related to running injuries and running mechanics.”