Ground reaction force data in functional ankle instability during two cutting movements.
ABSTRACT Functional instability of the ankle joint may interfere with proper execution of quick cutting movements in sports. Previous studies have provided information regarding the ground reaction force characteristics in such movements in healthy players but no research was found in players with ankle instability. The purpose of this study was to evaluate and compare ground reaction forces in functionally unstable ankles with healthy ones during two cutting movements, the v-cut and the defensive shuffle.
Fifteen male basketball players with self reported unilateral functional instability and 17 matched controls, performed three v-cuts and three defensive shuffles on two synchronised force platforms. Both joints were tested and ground reaction forces analysed by an one-way ANOVA for independent groups to test differences between groups, and paired t-test to examine differences within affected players.
Unstable ankles, demonstrated significantly greater first vertical force peak, than contralateral unaffected joints (P < or = 0.05) and lower relative time to peak than controls (P< or = 0.05), during v-cut movement. No significant differences were seen in variables between groups during lateral shuffling.
Unstable ankles demonstrated altered patterns of ground reaction forces, with a rapid onset of high vertical force during the first millisecond post-impact, while the medial component was unchanged. Although the increased vertical forces are considered predisposing factors to repeated injury, this finding is likely a neuromuscular response making the ankle joint more stable avoiding excessive inversion forces.
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ABSTRACT: This study assessed the validity of a tri-axial accelerometer worn on the upper body to estimate peak forces during running and change-of-direction tasks. Seventeen participants completed four different running and change-of-direction tasks (0 degrees, 45 degrees, 90 degrees, and 180 degrees; five trials per condition). Peak crania-caudal and resultant acceleration was converted to force and compared against peak force plate ground reaction force (GRF) in two formats (raw and smoothed). The resultant smoothed (10 Hz) and crania-caudal raw (except 180 degrees) accelerometer values were not significantly different to resultant and vertical GRF for all running and change-of-direction tasks, respectively. Resultant accelerometer measures showed no to strong significant correlations (r = 0.00-0.76) and moderate to large measurement errors (coefficient of variation [CV] = 11.7-23.9%). Crania-caudal accelerometer measures showed small to moderate correlations (r = -0.26 to 0.39) and moderate to large measurement errors (CV = 15.0-20.6%). Accelerometers, within integrated micro-technology tracking devices and worn on the upper body, can provide a relative measure of peak impact force experienced during running and two change-of-direction tasks (45 degrees and 90 degrees) provided that resultant smoothed values are used.Sports Biomechanics 11/2013; 12(4):403-12. DOI:10.1080/14763141.2013.811284 · 0.87 Impact Factor
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ABSTRACT: The forward-sprint is considered to be, and is regularly performed as, a unique measure of "on-ground" linear-speed performance. Thus far, no investigation has simultaneously studied different forms of linear-speed or investigated whether different forms of linear-speed should be observed as unique performance quality. The purpose of this study was to determine (I) the achievements (i.e. execution time), and (II) the reliability and inter-relationships between various linear-speed performances. The participants were 42 male physical education students with substantial sport-specific backgrounds. We applied a total of six tests: three quadrupedal (supine backward, supine forward, and pronate backward locomotion) and three bipedal-performances (forward sprinting, backward sprinting, lateral shuffling). All of the tests showed appropriate reliability parameters (Cronbach Alpha ranged from 0.91 to 0.97; Inter-Item-R 0.78-0.92; Coefficient-of-Variation 1.3-9.1). The tests used in this study shared between 9% and 50% of the common variance. Our results suggest that different activities require activity-specific tests of linear-speed. This is particularly significant in those sports and activities in which quadrupedal locomotion patterns are highly important (wrestling, physically trained military services, law enforcement, fire and rescue, protective services).Journal of Human Kinetics 10/2013; 38:53-61. DOI:10.2478/hukin-2013-0045 · 0.70 Impact Factor
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ABSTRACT: Force plates are commonly used to register ground reaction forces in order to assess neuromusculoskeletal function of the ankle joint. There exists a great variety in dynamic tests on force plates and in parameters calculated from ground reaction forces in order to evaluate neuromusculoskeletal function of the ankle. The purpose of this study was to evaluate which dynamic tests and force plate parameters are most sensitive to differences between and within groups with regard to foot and ankle pathology. A systematic review and meta-analysis was performed evaluating studies that compared force plate parameters of dynamic tests between patients with foot and ankle pathology, and healthy controls. Data were pooled per parameter and test category. Given the clinical heterogeneity, we constructed comprehensive recommendation criteria to indicate a 'proven relevant parameter' or 'candidate relevant parameter'. A total of 34 studies were included, and 58 relevant comparisons were identified. Results were subdivided by test category: walking, running, landing (in anteroposterior direction), sideways (movement in mediolateral direction) and termination (movement in anteroposterior direction). The 'walking' test showed significant differences in a great variety of pathologies, with the magnitude and timing of the 'second peak vertical force' as proven relevant parameters. The 'landing' test detected differences due to ankle instability, with 'time to stabilization in anteroposterior direction' as proven relevant parameter. This study provides recommendations concerning the potential of various dynamic tests and force plate parameters as a tool to compare neuromusculoskeletal function between patients with foot and ankle pathology and healthy controls.Clinical biomechanics (Bristol, Avon) 06/2013; DOI:10.1016/j.clinbiomech.2013.06.002 · 1.88 Impact Factor