Effect of Ankle Disk Training Combined With Tactile Stimulation to the Leg and Foot on Functional Instability of the Ankle.

Matsusaka N, Yokoyama S, Tsurusaki T, et al (School of Allied Medical Sciences, Nagasaki University; Department of Rehabilitation, Nagasaki University Hospital, Nagasaki, Japan), Am J Sports Med. 2001;29:25-30.

The purpose of this study was to determine whether the application of nonelastic tape to the lateral side of the ankle (from the sole to the lateral malleolus) of patients with functional instability of an ankle would decrease the time needed for rehabilitation. The rehabilitation training program consisted of a protocol using an ankle disk platform. The dependent variable was the mean rectangular area of anteroposterior and mediolateral postural sway as measured by a computer-controlled forceplate. Baseline forceplate data were compared with values obtained from people who were healthy and with values obtained following training on the ankle disk.

Twenty-two university students (10 women, 12 men; mean age=20.9 years) with a diagnosis of functional instability in one ankle volunteered to be in the study. The subjects were randomly assigned to either an experimental group that trained on an ankle disk platform (non-taping group) or an experimental group that trained on an ankle disk platform with 2 strips (1-cm wide) of nonelastic tape applied from the lateral malleolus to the sole of the foot (taping group). A control group of 21 subjects without ankle pathology (9 women, 12 men) also was included to provide normative values for postural sway.

During ankle disk training, the patient balanced on one foot on the ankle disk for as long as possible. Training was done for 10 minutes each day, 5 days per week, for 10 weeks. In this study, postural sway data from the one-legged stance were assumed to be an indicator of ankle functional instability--the more postural sway, the more ankle instability. Testing was done by having the subjects stand on one leg on a forceplate for 30 seconds while values of anterioposterior and mediolateral sway (defined as mean rectangular area [[cm.sup.2]]) were recorded. Testing for the experimental groups took place before training and alter weeks 2, 3, 4, 5, 6, 8, and 10. Tape was not worn during testing. The control group was tested for postural sway once at the beginning of the study. These measurements became the control values. All training and testing for both the experimental and the control groups were done barefoot.

The results for baseline postural sway for the 2 experimental groups did not differ; however, the control group baseline value for mean rectangular area (9.6 [cm.sup.2]) was significantly lower than those for the experimental groups (16.0 [cm.sup.2]). A 2-way ANOVA for repeated measures was done to determine if and when the baseline mean rectangular area differed from the mean rectangular area following training. The taping group did not demonstrate a significant difference in mean rectangular area when compared with baseline data at weeks 2 and 3, but a significant difference was observed at week 4. This value (11.2 [cm.sup.2]), however, was still significantly different from the normative data and, therefore, not the same as the postural sway value for the control group.

The mean rectangular area value for the taping group continued to fall with training, and, at 6 weeks, this value (9.0 [cm.sup.2]) was not different from the mean rectangular area of the control group. At this point the authors assumed that the functionally unstable ankle was functioning at the level of a healthy ankle. The non-taping group needed 6 weeks of training for the mean rectangular area to be significantly different from the baseline measurement and 8 weeks of training for the mean rectangular area to be statistically similar to that of the control group.

The researchers concluded that people with functional instability of the ankle who train on an ankle disk while wearing tape on the lateral side of their ankle will decrease their rehabilitation time by up to 2 weeks as compared with people who do not wear tape while training on an ankle disk. The authors hypothesized that the strips of tape may enhance the afferent input from the skin to the brain and spinal cord during training. The authors, however, felt that the small sample size limited the clinical significance of the study.

Richard J Kasser, PT, PhD
University of Tennessee Health Science
  Center
Memphis, Tenn