Effect of taping on actual and perceived dynamic postural stability in persons with chronic ankle instability.
Delahunt E, McGrath A, Doran N, Coughlan GF. Arch Phys Med Rehabil. 2010;91(9):1383-9.
Ankle sprains and instability may be hands down the most common injury in the sports medicine clinic. Ankle sprains occur in every sport, gender, and age group. Therefore, as healthcare professionals it is one of the first injuries we learn to evaluate and treat. Due to the high reoccurrence of ankle sprains, a subpopulation has been identified that develops chronic ankle instability (CAI). It is thought to be a combination of both mechanical and functional instability with patients reporting episodes of “giving way” or “feelings” of instability. Postural stability has been identified as a good measure for those with CAI. Particularly, the Star Excursion Balance Test (SEBT) is a great clinical way of examining stability. One of the most common methods for reducing CAI and preventing additional ankle sprains is the use of ankle tape. Ankle tape has been shown to decrease ankle sprains, however it has not been shown to increase postural stability; which is thought to be a risk factor for ankle injury. Therefore, the purpose of this study was to examine the effect of two taping techniques (3 conditions: lateral subtalar sling, fibular repositioning, and no tape) on postural stability; measured with the SEBT. 16 participants with CAI were tested in all three conditions. The participants also answered questions regarding their feeling of stability, reassurance, and confidence during the SEBT. They found that there were no significant differences in reach distance (part of the SEBT) for any of the three conditions. However, the study found that feelings of confidence increased among 56% of participants during both taped conditions. Feelings of stability increased for 88% of participants with the lateral subtalar sling and 75% of participants with the fibular repositioning. Feelings of reassurance increased for 69% of participants with the lateral subtalar sling and 50% of participants with the fibular repositioning.
This was a well designed study to address a clinical problem that is seen every day. It demonstrated that actual postural stability, measured with the SEBT, is not improved when an ankle is taped; however the participants’ “feeling” of stability, reassurance, and confidence were significantly enhanced. The authors did not go into much explanation for the observed results but suggested it may be due to a placebo effect. From our previous post on the placebo effect we know that the placebo effect is real and associated with physiological changes. The study findings may be the results of a placebo effect and I think many of us may feel this way when it comes to tape. However, we must consider other options. Theoretically, the tape may acutely enhance sensorimotor function thereby improving dynamic stability. One problem is that there was no improvement in stability measured using the SEBT. Therefore, we may need a more sensitive test for ankle instability. Another thought is that tape may enhance stability through a chronic mechanism instead of acutely. Balance and stability may only improve after several weeks of wearing the tape on a daily basis. If the mechanoreceptors within the ankle ligaments are less responsive and the tape improves sensory feedback from the skin to compensate for the damaged ligaments then the brain will need to adapt over time to receive and transmit proprioceptive information primarily from the skin and less from the ligaments. Similar central nervous system adaptations have been seen in individuals that become blind. This has never been demonstrated scientifically with respect to taping but may be plausible and would give clinicians more insight into the way taping can prevent ankle injuries. This would suggest that ankle tape would have to be applied on a daily basis to enhance functional stability and reduce the risk of re-injury among patients with CAI; however, this needs to be further researched. Also, it would be interesting to examine if similar results are found with the use of an ankle brace.
Written by: Stephen Thomas
Reviewed by: Jeffrey Driban
What kind of research is there regarding peroneal nerve injury associated with an inversion ankle sprain that contributes to CAI?
Tommy thanks for the post. That is a good question. There has been some research examining peroneal latency and electromechanical delays in patients with functional ankle instability (https://www.ncbi.nlm.nih.gov/pubmed/19569189) and (https://www.ncbi.nlm.nih.gov/pubmed/19270189). Based on this it is suggested that the peroneal nerve is affected due to the ankle instability however we do not know if this is caused by direct injury to the peroneal nerve or due to injury to the mechnoreceptors of the lateral ankle ligaments which causes electromechanical delays to the peroneal muscle. Are there any ankle experts out there that can better answer this?