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Eric Foch and Clare E. Milner

have a cumulative damaging effect on the iliotibial band. 12 In addition to atypical coordination patterns, coordination variability may also differ in injured runners compared with controls. For example, lowering coordination variability may be a compensatory mechanism used by runners with previous

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Adam E. Jagodinsky, Christopher Wilburn, Nick Moore, John W. Fox and Wendi H. Weimar

would help improve our understanding of how bracing works to be effective in individuals with and without CAI. Coordination variability may be considered fluctuations in the coordination pattern between 2 segments and can be measured to assess motor adaptations in the presence of constraints (eg

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Ben Serrien, Maggy Goossens and Jean-Pierre Baeyens

athletes. Not only does the average motion pattern across participants deserve attention, but so does the within-subject coordination variability, from a motor control and sport science perspective. Coordination variability (CV) should not be solely interpreted as neuromuscular noise, but for its profound

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Behrouz Abdoli, James Hardy, Javad F. Riyahi and Alireza Farsi

, McGuigan, & Thatcher, 2009 ), comparing the movement coordination variability associated with instructional and motivational self-talk was another objective for the present study. Targeting movement coordination afforded us the opportunity to examine more closely how self-talk might influence skilled

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Joseph F. Seay, Jeffery M. Haddad, Richard E.A. van Emmerik and Joseph Hamill

Increases in movement variability have previously been observed to be a hallmark property of cooraination changes between coupled oscillators that occur as movement frequency is scaled. Prior research on the walk-run transition in human locomotion has also demonstrated increases in variability around the transition region, supporting predictions of nonequilibrium phase transitions (Diedrich & Warren, 1995). The current study examined the coordinative patterns of both intra- and inter-limb couplings around the walk-run transition using two different temporal manipulations of locomotor velocity as a control parameter in healthy young participants (N = 11). Coordination variability did not increase before the transition. The nature of the change in continuous relative phase variability between gait modes was coupling-specific, and varying the time spent at each velocity did not have an overall effect on gait transition dynamics. Lower extremity inter-limb coordination dynamics were more sensitive to changes in treadmill velocity than intra-limb coordination. The results demonstrate the complexity of segmental coordination change in human locomotion, and question the applicability of dynamical bimanual coordination models to human gait transitions.

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Christopher J. Palmer and Richard E.A. van Emmerik

). Generation of increased inertial forces with increases in load during rapid postural transitions was predicted to “push” head, gun, and trunk relations from optimal baseline unloaded coupling angles, increasing between-trial coordination variability (Hypothesis 2). Time between movement cessation and trigger

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Christopher L. MacLean, Richard van Emmerik and Joseph Hamill

The purpose of this study was to analyze the influence of a custom foot orthotic (CFO) intervention on lower extremity intralimb coupling during a 30-min run in a group of injured runners and to compare the results to a control group of healthy runners. Three-dimensional kinematic data were collected during a 30-min run on healthy female runners (Shoe-only) and a group of female runners who had a recent history of overuse injury (Shoe-only and Shoe with custom foot orthoses). Results from the study revealed that the coordination variability and pattern for the some couplings were influenced by history of injury, foot orthotic intervention and the duration of the run. These data suggest that custom foot orthoses worn by injured runners may play a role in the maintenance of coordination variability of the tibia (transverse plane) and calcaneus (frontal plane) coupling during the Early Stance phase. In addition, it appears that the coupling angle between the knee (transverse plane) and rearfoot (frontal plane) joints becomes more symmetrical in the late stance phase as a run progresses.

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Hai-Jung Steffi Shih, Danielle N. Jarvis, Pamela Mikkelsen and Kornelia Kulig

central nervous system often controls movement variability based on task relevance. For example, expert dancers exhibit greater trunk coordination variability right before landing of bipedal jumps, possibly a combined effect of feedback control from each unique flight characteristic and feedforward

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Scott W. Ducharme and Richard E.A. van Emmerik

locomotion ( Hamill, Van Emmerik, Heiderscheit, & Li, 1999 ; Wagenaar & Van Emmerik, 1994 ). Much of this research emerged from a dynamical systems perspective on human movement with a special emphasis on coordination and coordination variability. Next, we will briefly review what clinical gait and sports

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Michael A. Samaan, Matthew C. Hoch, Stacie I. Ringleb, Sebastian Bawab and Joshua T. Weinhandl

The aim of this study was to determine the effects of hamstrings fatigue on lower extremity joint coordination variability during a sidestep cutting maneuver. Twenty female recreational athletes performed five successful trials of a sidestep cutting task preand postfatigue. Each participant completed an isolated hamstrings fatigue protocol consisting of isokinetic maximum effort knee flexion and passive extension contractions. Vector coding was used to examine hip and knee joint couplings (consisting of various planar motions) during the impact and weight acceptance phases of the sidestep cut stance phase. Paired t tests were used to analyze differences of each phase as an effect of fatigue, where alpha was set a priori at .05. The hip rotation/knee rotation coupling exhibited a significant decrease in coordination variability as a function of fatigue in both the impact (P = .015) and weight acceptance phases (P = .043). Similarly, the hip adduction-abduction/knee rotation coupling exhibited a significant decrease in coordination variability in the weight acceptance phase (P = .038). Hamstrings fatigue significantly decreased coordination variability within specific lower extremity joint couplings that included knee rotation. Future studies should be conducted to determine if this decrease in coordination variability is related to lower extremity injury mechanisms.