The effect of intermittent ice application on dynamic postural control. Andrew C. S. Mitchell and Peter Thain. Biomechanics Research Group, University of Hertfordshire, Hatfield, Hertfordshire, United Kingdom First coined by Hayden and Grant in 1964, cryokinetics, literally meaning ‘cold’ and ‘motion’, is the application of ice to induce an analgesic effect with subsequent pain-free exercises being performed. Cryokinetics is used throughout the rehabilitation process to decrease pain and muscle spasm thereby facilitating exercise, with implementation prevalent in the latter stages prior to sprinting and sharp cutting manoeuvres being performed. PURPOSE: The purpose of this study was to examine the effects of intermittent ice application on dynamic postural sway following a drop jump landing. METHODS: Twenty-four physically active students (males n = 12, age 19.5 years ± 0.9, height 175.2cm ± 5.4, mass 74.7kg ± 13.2, females n = 12, age 20.0 years ± 0.7, height 164.1cm ± 6.5, mass 59.1kg ± 7.9) volunteered to take part in the study. Human subject approval was granted by the institutional ethics committee, with informed written consent obtained. Subjects were positioned on a bench standing on the non-dominant leg, with the dominant leg flexed to 45° at the hip, before dropping from the bench and landing with the dominant leg onto a pressure plate. Changes in centre-of-pressure during the landing from the 30cm drop jump were recorded a total of 3 times. Crushed ice (1.5L) was placed into a fabric bag, held under running warm water for 30s, and applied to the lateral aspect of the subject's ankle. Three 30cm drop jumps were completed and postural sway measured after the initial ice application, with subsequent measures performed after; 10-minutes rest, 10-minutes ice, and 10-minutes rest. Normality of data was verified using the Shapiro-Wilk test. Within-subjects repeated measures (ANOVA) were performed. Specific post hoc pairwise comparisons between the pre-treatment and post-ice conditions were made. The alpha level was set at P<0.05. RESULTS: Repeated measures ANOVA indicated significant differences across time for peak medial (P = 0.008), total anterior (P = 0.011) and total posterior (P = 0.012) postural sway. Post hoc pairwise comparisons identified significant differences between the pre-treatment and the second 10-minute ice (P = 0.011), and between the first 10-minute ice and the second 10-minute ice application (P = 0.029) for peak medial sway. Further pairwise comparisons identified significant differences between the pre-treatment and the second 10-minute ice for total anterior sway (P = 0.036), and for total posterior sway (P = 0.039). CONCLUSIONS: The results suggest that intermittent ice application to the ankle is advantageous to postural control during dynamic activity and may elicit a shift from ankle to hip strategy, thus recruiting the larger musculature of the hip joint. Postural control was shown to improve in the current study, with previous studies identifying increased motorneuron recruitment. This study supports the previous findings that have shown joint cooling is beneficial in exercise rehabilitation. This cryokinetic protocol reduced postural sway from a drop landing, giving evidence to show it is a viable rehabilitation technique. PRACTICAL APPLICATIONS: Intermittent ice application is recommended prior to dynamic full-weight-bearing proprioceptive exercises, which may be prescribed during the late stages of rehabilitation. Not only does ice application reduce the athlete's sensation of pain, it may also enable exercises to be performed earlier than would normally be possible.