Laboratory study using a repeated measures design. The aim of this study was to determine if ankle proprioception is targeted in exercises on unstable surfaces. Lateral ankle sprain (LAS) has recurrence rates over 70%, which are believed to be due to a reduced accuracy of proprioceptive signals from the ankle. Proprioceptive exercises in rehabilitation of LAS mostly consist of balancing activities on an unstable surface. The methods include 100 healthy adults stood barefoot on a solid surface and a foam pad over a force plate, with occluded vision. Mechanical vibration was used to stimulate proprioceptive output of muscle spindles of triceps surae and lumbar paraspinal musculature. Each trial lasted for 60 s; vibration was applied from the 15th till the 30th second. Changes in mean velocity and mean position of the center of pressure (CoP) as a result of muscle vibration were calculated. Results show that on foam, the effect of triceps surae vibration on mean CoP velocity was significantly smaller than on a solid surface, while for paraspinal musculature vibration the effect was bigger on foam than on solid surface. Similar effects were seen for mean CoP displacement as outcome. Exercises on unstable surfaces appear not to target peripheral ankle proprioception. Exercises on an unstable surface may challenge the capacity of the central nervous system to shift the weighting of sources of proprioceptive signals on balance.
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We read the recent manuscript by Kal et al.1 ‘Explicit motor learning interventions are still relevant for ACL injury rehabilitation: do not put all your eggs in the implicit basket‘ with great interest. The authors did a commendable job summarizing the current literature and we highly respect them for being critical, to foster academic discussions to move science forward. We do however have some concerns regarding the methodology and interpretations made by the authors.
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Objective. There are no Dutch language disease-specific questionnaires for patients with patellofemoral pain syndrome available that could help Dutch physiotherapists to assess and monitor these symptoms and functional limitations. The aim of this study was to translate the original disease-specific Kujala Patellofemoral Score into Dutch and evaluate its reliability. Methods. The questionnaire was translated from English into Dutch in accordance with internationally recommended guidelines. Reliability was determined in 50 stable subjects with an interval of 1 week. The patient inclusion criteria were age between 14 and 60 years; knowledge of the Dutch language; and the presence of at least three of the following symptoms: pain while taking the stairs, pain when squatting, pain when running, pain when cycling, pain when sitting with knees flexed for a prolonged period, grinding of the patella and a positive clinical patella test. The internal consistency, test–retest reliability, measurement error and limits of agreement were calculated. Results. Internal consistency was 0.78 for the first assessment and 0.80 for the second assessment. The intraclass correlation coefficient (ICCagreement) between the first and second assessments was 0.98. The mean difference between the first and second measurements was 0.64, and standard deviation was 5.51. The standard error measurement was 3.9, and the smallest detectable change was 11. The Bland and Altman plot shows that the limits of agreement are 10.37 and 11.65. Conclusions. The results of the present study indicated that the test–retest reliability translated Dutch version of the Kujala Patellofemoral Score questionnaire is equivalent of the test– retest original English language version and has good internal consistency. Trial registration NTR (TC = 3258). Copyright © 2015 John Wiley & Sons, Ltd.