• The effect of repetitive ankle perturbations on muscle reaction time and muscle activity

      Thain, Peter K.; Hughes, Gerwyn T.G.; Mitchell, Andrew C.S.; Birmingham City University; University of San Francisco; University of Bedfordshire; University of Hertfordshire (Elsevier Ltd, 2016-07-15)
      The use of a tilt platform to simulate a lateral ankle sprain and record muscle reaction time is a well-established procedure. However, a potential caveat is that repetitive ankle perturbation may cause a natural attenuation of the reflex latency and amplitude. This is an important area to investigate as many researchers examine the effect of an intervention on muscle reaction time. Muscle reaction time, peak and average amplitude of the peroneus longus and tibialis anterior in response to a simulated lateral ankle sprain (combined inversion and plantar flexion movement) were calculated in twenty-two physically active participants. The 40 perturbations were divided into 4 even groups of 10 dominant limb perturbations. Within-participants repeated measures analysis of variance (ANOVA) tests were conducted to assess the effect of habituation over time for each variable. There was a significant reduction in the peroneus longus average amplitude between the aggregated first and last 10 consecutive ankle perturbations (F = 3.90, P = 0.03, ɳ  = 0.16). Authors should implement no more than a maximum of 30 consecutive ankle perturbations (inclusive of practice perturbations) in future protocols simulating a lateral ankle sprain in an effort to avoid significant attenuation of muscle activity.
    • Muscle reaction time during a simulated lateral ankle sprain after wet-ice application or cold-water immersion

      Thain, Peter K.; Bleakley, Christopher M.; Mitchell, Andrew C.S.; University of Hertfordshire; Ulster University; University of Bedfordshire (NATL ATHLETIC TRAINERS ASSOC INC, 2015-07-01)
      Context: Cryotherapy is used widely in sport and exercise medicine to manage acute injuries and facilitate rehabilitation. The analgesic effects of cryotherapy are well established; however, a potential caveat is that cooling tissue negatively affects neuromuscular control through delayed muscle reaction time. This topic is important to investigate because athletes often return to exercise, rehabilitation, or competitive activity immediately or shortly after cryotherapy.Objective: To compare the effects of wet-ice application, cold-water immersion, and an untreated control condition on peroneus longus and tibialis anterior muscle reaction time during a simulated lateral ankle sprain.Design: Randomized controlled clinical trial.Setting: University of Hertfordshire human performance laboratory.Patients or Other Participants: A total of 54 physically active individuals (age = 20.1 +/- 1.5 years, height = 1.7 +/- 0.07 m, mass = 66.7 +/- 5.4 kg) who had no injury or history of ankle sprain.Intervention(s): Wet-ice application, cold-water immersion, or an untreated control condition applied to the ankle for 10 minutes.Main Outcome Measure(s): Muscle reaction time and muscle amplitude of the peroneus longus and tibialis anterior in response to a simulated lateral ankle sprain were calculated. The ankle-sprain simulation incorporated a combined inversion and plantar-flexion movement.Results: We observed no change in muscle reaction time or muscle amplitude after cryotherapy for either the peroneus longus or tibialis anterior (P < .05).Conclusions: Ten minutes of joint cooling did not adversely affect muscle reaction time or muscle amplitude in response to a simulated lateral ankle sprain. These findings suggested that athletes can safely return to sporting activity immediately after icing. Further evidence showed that ice can be applied before ankle rehabilitation without adversely affecting dynamic neuromuscular control. Investigation in patients with acute ankle sprains is warranted to assess the clinical applicability of these interventions.