Relative phase quantifies interjoint coordination

Burgess-Limerick, Robin; Abernethy, Bruce; Neal, Robert J.

doi:10.1016/0021-9290(93)90617-n

Cited by 141 publications

(101 citation statements)

References 6 publications

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“…First, angular position and velocity data were normalized to a unit circle using the maximum and minimum values (van Emmerik & Wagenaar, 1996). Second, angular position and velocity data were normalized to ±1 along the position axis, and to +1 or -1 along the velocity axis, depending on where the maximum absolute velocity occurred (Burgess-Limerick et al, 1993). Each of the above techniques were employed, with the normalization occurring on a stride-per-stride basis or with normalization occurring over the maximum values of multiple strides (Haddad et al, 1999).…”

Section: Continuous Relative Phase (Crp)mentioning

confidence: 99%

Issues in Quantifying Variability from a Dynamical Systems Perspective

Hamill¹,

Haddad²,

McDermott³

2000

Journal of Applied Biomechanics

189

120

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Variability is a critical aspect of a dynamical systems analysis. Because there are a number of numerical techniques that can be used in such an analysis, the calculation of variability has several issues that must be addressed. The purpose of this paper is to present a variety of quantitative methods for investigating variability from a dynamical systems perspective. The paper is divided into two major sections covering discrete and continuous methods. Each of these sections is subdivided into two sections. Within discrete methods, we discuss, first, the calculation of the discrete relative phase from a time-series history of two parameters and, second, the use of return maps. Using continuous methods, we present procedures for using angle-angle plots in the evaluation of relative phase. We then discuss the use of phase plots in the calculation of the continuous relative phase. Each of these methods presents unique problems for the researcher and the method to be used is determined by the nature of the question asked.

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Section: Continuous Relative Phase (Crp)mentioning

confidence: 99%

Issues in Quantifying Variability from a Dynamical Systems Perspective

Hamill¹,

Haddad²,

McDermott³

2000

Journal of Applied Biomechanics

189

120

View full text Add to dashboard Cite

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“…However, such presentations do not reveal the direct relationship between velocity changes and position [5,37,38]. It is important to evaluate this relationship in an ACLreconstructed knee since the ACL provides sensory feedback on both velocity and position [13,21].…”

mentioning

confidence: 99%

The effect of anterior cruciate ligament recontruction on lower extremity relative phase dynamics during walking and running

Kurz

Stergiou

Buzzi

et al. 2004

Knee Surg Sports Traumatol Arthrosc

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The purpose of this investigation was to use relative phase dynamics to evaluate gait in individuals with a reconstructed anterior cruciate ligament (ACL) during walking and running. Relative phase dynamics can describe the coordination strategies between the interacting segments at the lower extremity. Ten subjects who had undergone ACL reconstruction using the central third of their patellar tendon and ten healthy controls walked and ran on a treadmill at a self-selected pace. Relative phase dynamics were calculated for the foot-shank and shank-thigh coordinative relationships. Statistical differences between the groups were noted for the foot-shank relationship (p < 0.05) during both walking and running and for the shank-thigh relationship (p < 0.05) during walking. Our results indicate that current ACL reconstructive techniques may result in altered relative phase dynamics. These changes in relative phase dynamics could be related to a loss of sensory information about joint position and velocity that is typically provided by the intact ACL. Additionally, relative phase adaptations could be a learned response from the early stages of postsurgical rehabilitation. Relative phase dynamics provide quantitative information about the dynamic status of the ACL-reconstructed knee that cannot be gained from the conventional time-series evaluation of gait analysis data. Relative phase dynamics measures should supplement the conventional gait analysis measures that are used today for the clinical evaluation of the functional dynamic stability of the reconstructed knee. The examination of relative phase dynamics could be clinically important for the quantification of new ACL surgical interventions and of patient performance at various stages of rehabilitation. Further research should incorporate relative phase dynamics to understand the influence of ACL reconstruction on coordination and functional patient outcomes.

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“…Although individual segmental range of motion has been quantified for all spinal levels, 1 in vivo research from a biomechanical and motor control perspective has typically approximated the thoracolumbar spine [2][3][4][5][6][7][8][9] or the lumbar spine 10 -14 as a single segment. In a limited number of studies, the thoracolumbar spine has been segmented to yield one thoracic and one lumbar angle, 15,16 while other studies have used in vivo kinematics to determine regional movement in the thoracic spine 17 and the lumbar spine, 18 with the spine region under examination being divided into several segments.…”

mentioning

confidence: 99%

Regional Changes in Spine Posture at Lift Onset With Changes in Lift Distance and Lift Style

Gill¹,

Bennett²,

Savelsbergh³

et al. 2007

Spine

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Study Design. Repeated measures experiment. Objective. To determine the effect of changes in horizontal lift distance on the amount of flexion, at lift onset, in different spine regions when using different lift styles.Summary of Background Data. By approximating spine bending during lifting as a pure rotation about a single revolute joint, the differential effects of task constraints and instructions on motions of different spine levels will be obscured.Methods. Eight participants lifted a 10-kg crate from the floor, 10 times at each of five distances. Participants were instructed to use freestyle (a participant's preferred lift style), squat, or stoop lift styles. Kinematic data were collected from the mid thoracic spine, lower thoracic/ upper lumbar spine, mid lumbar spine, and the lower lumbar spine at lift onset. A whole spine angle was also calculated.Results. Flexion of the lower lumbar spine was not affected by lift distance and style. Differences between lift styles occurred mainly in the mid thoracic and the lower thoracic/upper lumbar regions. With increasing horizontal distance, changes in lift style occurred in the upper three spine regions.Conclusions. These results suggest that the tensile strain on tissues in the lower lumbar spine, which can be a cause of injury in lifting, was not affected by lift style or horizontal lift distance when lifting from floor level.

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Relative phase quantifies interjoint coordination

Cited by 141 publications

References 6 publications

Issues in Quantifying Variability from a Dynamical Systems Perspective

Issues in Quantifying Variability from a Dynamical Systems Perspective

The effect of anterior cruciate ligament recontruction on lower extremity relative phase dynamics during walking and running

Regional Changes in Spine Posture at Lift Onset With Changes in Lift Distance and Lift Style

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