Richard E A Van Emmerik

University of Massachusetts Amherst, Amherst Center, Massachusetts, United States

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Publications (111)231.94 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Excessive pronation, because of its coupling with tibial internal rotation (TIR), has been implicated as a risk factor in the development of anterior knee pain (AKP). Traditionally this coupling has been expressed as a ratio between the eversion range of motion and the TIR range of motion (Ev/TIR) that occurs during stance. Currently, this technique has not been used to evaluate specific injuries or the effects of gender. Additionally, Ev/TIR is incapable of detecting coupling changes that occur throughout stance. Therefore, the purpose of this study was to compare the coupling between eversion and TIR in runners with (n = 19) and without AKP (n = 17) and across gender using the Ev/TIR ratio, and more continuously using vector coding. When using vector coding, significant coupling differences were noted in runners with AKP (34-38% stance), with runners with AKP showing relatively more TIR than eversion. Similarly significant differences were noted across gender (14-25 & 36-47% stance) with males transitioning from a loading to propulsive coordination pattern using a proximal to distal strategy, while female runners used a distal to proximal strategy. These differences were only detected when evaluating this coupling relationship using a continuous technique such as vector coding.
    Journal of applied biomechanics. 11/2014;
  • Ryan Chang, Pedro A Rodrigues, Richard E A Van Emmerik, Joseph Hamill
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    ABSTRACT: Clinically, plantar fasciitis (PF) is believed to be a result and/or prolonged by overpronation and excessive loading, but there is little biomechanical data to support this assertion. The purpose of this study was to determine the differences between healthy individuals and those with PF in (1) rearfoot motion, (2) medial forefoot motion, (3) first metatarsal phalangeal joint (FMPJ) motion, and (4) ground reaction forces (GRF).
    Journal of biomechanics. 06/2014;
  • J G Remelius, J Hamill, R E A van Emmerik
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    ABSTRACT: This study examined the prospective control of the swing phase in young healthy adults while walking at preferred speed over unobstructed ground and during obstacle clearance. Three aspects of swing were examined: (1) the relation of the body Center of Mass (CoM) to the stability boundaries at the base of support; (2) a dynamic time-to-contact analysis of the CoM and swing foot to these boundaries; and (3) the role of head movements in the prospective control of gait and field of view assessment. The time-to-contact analysis of CoM and swing foot showed less stable swing dynamics in the trail foot compared to the lead foot in the approach to the unstable equilibrium, with the CoM leading the swing foot and crossing the anterior stability boundary before the swing foot. Compensations in temporal coupling occurred in the trail limb during the late swing phase. Time-to-contact analysis of head movement showed stronger prospective control of the lead foot, while fixation of the field of view occurred earlier in swing and was closer to the body in the obstacle condition compared to unobstructed walking. The dynamic time-to-contact analysis offers a new approach to assessing the unstable swing phase of walking in different populations.
    Human movement science. 05/2014;
  • Advances in experimental medicine and biology 01/2014; 826:251-76. · 1.83 Impact Factor
  • Joseph F Seay, Richard E A Van Emmerik, Joseph Hamill
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    ABSTRACT: Abstract Recent literature has related differences in pelvis-trunk coordination to low back pain (LBP) status. In addition, repetitive motions involving bending and twisting have been linked to high incidence of LBP. The purpose of this study was to examine trunk sagittal motion - axial rotation ('bend and twist') coordination during locomotion in three groups of runners classified by LBP status (LBP: current low back pain; RES: resolved low back pain and CTR: control group with no history of LBP). Trunk kinematic data were collected as running speed was systematically increased on a treadmill. Within-segment coordination between trunk sagittal and transverse planes of motion (trunk lean and axial rotation, respectively) was calculated using continuous relative phase (CRP), and coordination variability was defined as the between stride cycle standard deviation of CRP (CRPvar). Bend-twist coordination was more in-phase for the LBP group than CTR (p = 0.010) regardless of running speed. No differences in CRPvar were found between the groups. The results from our coordination (CRP) analysis were sensitive to LBP status and suggest that multi-plane interactions of the trunk should be considered in the assessment of LBP. This analysis also has potential for athletically oriented tasks that involve multi-plane interactions of the trunk, particularly ones that contain asymmetric action, such as sweep rowing or a shot on goal in field hockey or ice hockey.
    European journal of sport science. 12/2013;
  • Christopher J Palmer, Carol Bigelow, Richard E A Van Emmerik
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    ABSTRACT: Soldier equipment compromises task performance as temporal constraints during critical situations and load increase inertial and interactive forces during movement. Methods are necessary to optimise equipment that relate task performance to underlying coordination and perception-action coupling. Employing ecological task analysis and methods from dynamical systems theory, equipment load and coordination was examined during two sub-tasks embedded in combat performance, threat discrimination and dynamic marksmanship. Perception-action coupling was degraded with load during threat discrimination, leading to delays in functional reaction time. Reduced speed and accuracy during dynamic marksmanship under load was related to disrupted segmental coordination and adaptability during postural transitions between targets. These results show how reduced performance under load relates to coordination changes and perception-action coupling. These changes in functional capability are directly related to soldier survivability in combat. The methods employed may aid equipment design towards more optimised performance by modifying equipment or its distribution on humans. Practitioner Summary: The combat equipment necessary for soldier survival and mission accomplishment significantly impedes task performance. Understanding relations among equipment, task performance, situational awareness and segmental coordination is necessary to define the trade space for design optimisation. This article begins to define this trade space in terms of perception-action coupling and survivability in combat.
    Ergonomics 09/2013; · 1.67 Impact Factor
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    ABSTRACT: Little biomechanical evidence exists to support the association between excessive foot pronation and anterior knee pain (AKP). One issue could be the way excessive pronation has been defined. Recent evidence has suggested that evaluating pronation in the context of the joint's available range of motion (ROM, anatomical threshold) provides greater insight on when pronation contributes to injury. Theoretically, quantifying the amount of time the joint has to respond before reaching end range (neuromuscular threshold) could provide additional insight. Therefore the purpose of this study was to use a neuromuscular threshold, the time to contact (TtC) the ankle joint complex's ROM boundary, to evaluate runners with and without AKP. Nineteen healthy and seventeen runners with AKP had their ROM and running biomechanics evaluated. The TtC was calculated using each individual's angular distance from end range (eversion buffer) and eversion velocity. Data were recorded over ten stance phases and evaluated using a one way analysis of variance and 95% confidence intervals. Runners with AKP had significantly shorter TtC the joint's ROM boundary when compared to healthy runners (64.0ms vs. 35.6ms, p=0.01). While not statistically significant, this shorter TtC was in large part due to having a smaller eversion buffer, however velocity was found to have a substantial influence on the TtC of select individuals. These results provide evidence that a link between pronation and AKP exists when using anatomical and neuromuscular based thresholds.
    Gait & posture 06/2013; · 2.58 Impact Factor
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    ABSTRACT: The aim of this paper was to present a review on the role that movement variability (MV) plays in the analysis of sports movement and in the monitoring of the athlete's skills. MV has been traditionally considered an unwanted noise to be reduced, but recent studies have re-evaluated its role and have tried to understand whether it may contain important information about the neuro-musculo-skeletal organisation. Issues concerning both views of MV, different approaches for analysing it and future perspectives are discussed. Information regarding the nature of the MV is vital in the analysis of sports movements/motor skills, and the way in which these movements are analysed and the MV subsequently quantified is dependent on the movement in question and the issues the researcher is trying to address. In dealing with a number of issues regarding MV, this paper has also raised a number of questions which are still to be addressed.
    Sports Biomechanics 06/2013; 12(2):69-92. · 0.74 Impact Factor
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    Joseph Hamill, Christopher Palmer, Richard E Van Emmerik
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    ABSTRACT: Overuse injuries are generally defined as a repetitive micro-trauma to tissue. Many researchers have associated particular biomechanical parameters as an indicator of such injuries. However, while these parameters have been reported in single studies, in many instances, it has been difficult to verify these parameters as causative to the injury. We have investigated overuse injuries, such as patella-femoral pain syndrome, using a dynamical systems approach. Using such methods, the importance of the structure of coordinative variability (i.e. the variability of the interaction between segments or joints) becomes apparent. We view coordinative variability as functionally important to the movement and different from end-point or goal variability. Using concepts derived from the work of Bernstein, we conducted studies using a continuous relative phase and/or modified vector coding approaches to investigate the coordinative variability of overuse injuries. Consistently, we have found that the higher variability state of a coordinative structure is the healthy state while the lower variability state is the unhealthy or pathological state. It is clear that very high coordinative variability could also result in injury and that there must be a window of 'higher variability' in which non-injured athletes function. While this finding that coordinative variability is functional has been shown in several studies, it is still not clear if reduced variability contributes to or results from the injury. Studies are currently underway to determine the potential reasons for the reduced variability in injured athletes. Nevertheless, our laboratory believes that this understanding of how joints interact can be important in understanding overuse injuries.
    Sports Medicine Arthroscopy Rehabilitation Therapy & Technology 11/2012; 4(1):45.
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    ABSTRACT: To investigate (1) whether previously observed changes in gait parameters in individuals with multiple sclerosis (MS) are the result of slower preferred walking speeds or reflect adaptations independent of gait speed; and (2) the changes in spatiotemporal features of the unstable swing phase of gait in people with MS. Cross-sectional study assessing changes in gait parameters during preferred, slow (0.6m/s), medium (1.0m/s), and fast (1.4m/s) walking speeds. Gait laboratory with instrumented walkway and motion capture system. MS group with mild to moderate impairment (n=19, 16 women) with a median Expanded Disability Status Scale score of 3.75 (range, 2.5-6), and a sex- and age-matched control group (n=19). Not applicable. Gait speed, stride length, stride width, cadence, dual support time, swing time, and timing of swing foot and body/head center of mass during swing phase. Individuals with MS walked at slower preferred speeds with longer dual support times compared with controls. In fixed-speed conditions, dual support times were longer and swing times were shorter in MS compared with controls. Stride width was wider for all speed conditions in the MS group. In fixed-speed conditions, the MS group positioned their head and body centers of mass closer to the anterior base of support boundary when entering the unstable equilibrium of the swing phase. Longer dual support time is part of a gait strategy in MS that is apparent even when controlling for the confounding effect of slower preferred speed. However, a gait strategy featuring longer dual support times may have limitations if potentially destabilizing swing dynamics exist, which especially occur at walking speeds other than preferred for people with MS.
    Archives of physical medicine and rehabilitation 03/2012; 93(9):1637-42. · 2.18 Impact Factor
  • Christopher J. Palmer, Gary E. Riccio, Richard E. A. Van Emmerik
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    ABSTRACT: Orientation toward one's surroundings is necessary for prospective control of action, and constraints on orienting activity have consequences for animal survival. Physically coupled load is a constraint for humans wearing protective equipment (firefighters, soldiers, etc.). The consequences of load on postural affordances while transitioning to upright stance was used to quantify the impact of different soldier configurations. Eight participants established upright posture in 4 relevant load configurations (5.0 to 79.2 lb). Load affected the accessibility of optical information at a distance as evidenced by increasing downward head angles and reductions in postural coordination. Reductions in the variability of time to establish upright stance with load suggests a loss of functional adaptability. Load asymmetries played a significant role as the most asymmetric configuration (not the heaviest) had the most detrimental effect on postural affordances. Center of Pressure (CoP) dynamics reflected the consequences of asymmetric loading on postural regulation as greater power and fluctuations across frequencies were observed. Physically coupled load induces significant constraints on orienting activity, and load asymmetry contributes significantly to the detrimental effects of protective equipment on action-perception coupling during whole-body movements.
    Ecological Psychology - ECOL PSYCHOL. 01/2012; 24(2):95-121.
  • Molly B Johnson, Richard E A Van Emmerik
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    ABSTRACT: During stance, head extension increases postural sway, possibly due to interference with sensory feedback. The sit-to-stand movement is potentially destabilizing due to the development of momentum as the trunk flexes forward and the body transitions to a smaller base of support. It is unclear what role head orientation plays in the postural and movement characteristics of the sit-to-stand transition. The authors assessed how moving from sitting to standing with head-on-trunk extension compared with moving with the head neutral or flexed, or with moving with the head facing forward in space (which would involve head-on-trunk extension, but not head-in-space extension) in healthy, young participants. Head-on-trunk extension increased center of pressure variability, but decreased movement velocities, movement duration, and trunk flexion compared with flexed and neutral head-on-trunk orientations. Similarities in movement characteristics between head-on-trunk extension and the forward head-in-space orientation suggest that stabilizing the head in space does not fully counteract the postural and movement changes due to head-on-trunk extension. Findings suggest that proprioceptive feedback from the neck muscles contributes to the regulation of posture and movement, and therefore should not be overlooked in research on the role of sensory feedback in postural control.
    Journal of Motor Behavior 11/2011; 43(6):491-8. · 1.04 Impact Factor
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    ABSTRACT: Studies have suggested that proper postural control is essential for the development of reaching. However, little research has examined the development of the coordination between posture and manual control throughout childhood. We investigated the coordination between posture and manual control in children (7- and 10-year-olds) and adults during a precision fitting task as task constraints became more difficult. Participants fit a block through an opening as arm kinematics, trunk kinematics, and center of pressure data were collected. During the fitting task, the precision, postural, and visual constraints of the task were manipulated. Young children adopted a strategy where they first move their trunk toward the opening and then stabilize their trunk (freeze degrees of freedom) as the precision manual task is being performed. In contrast, adults and older children make compensatory trunk movements as the task is being performed. The 10-year-olds were similar to adults under the less constrained task conditions, but they resembled the 7-year-olds under the more challenging tasks. The ability to either suppress or allow postural fluctuations based on the constraints of a suprapostural task begins to develop at around 10 years of age. This ability, once developed, allows children to learn specific segmental movements required to complete a task within an environmental context.
    Journal of Experimental Child Psychology 10/2011; 111(2):286-98. · 3.12 Impact Factor
  • Joseph F Seay, Richard E A Van Emmerik, Joseph Hamill
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    ABSTRACT: The purpose of this study was to compare pelvis-trunk coordination and coordination variability over a range of walking and running speeds between three groups of runners; runners with low to moderate low back pain; runners who had recovered from a single bout of acute low back pain; and runners who had never experienced any symptoms of low back pain. Pelvis and trunk kinematic data were collected as speed was systematically increased on a treadmill. Coordination between pelvis and trunk in all three planes of motion was measured using continuous relative phase, and coordination variability was defined as the standard deviation of this measure. Oswestry Disability Index indicated the low back pain group was high functioning (mean 7.9% out of 100%). During walking, frontal plane coordination was more in-phase for the low back pain group compared to controls (P=0.029), with the resolved group showing an intermediate coordination pattern (P=0.064). During running, both low back pain (P=0.021) and resolved (P=0.025) groups showed more in-phase coordination in the transverse plane than the control group. The low back pain group also showed reduced transverse plane coordination variability compared to controls (P=0.022). Coordination and coordination variability results showed a continuum of responses between our three groups. Taken together, the data lend insight into increased injury risk and performance deficits associated with even one bout of low back pain, and suggest that clinicians need to look beyond the resolution of pain when prescribing rehabilitation for low back pain.
    Clinical biomechanics (Bristol, Avon) 07/2011; 26(6):572-8. · 1.76 Impact Factor
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    ABSTRACT: Locomotor respiratory coupling patterns in humans have been assessed on the basis of the interaction between different physiological and motor subsystems; these interactions have implications for movement economy. A complex and dynamical systems framework may provide more insight than entrainment into the variability and adaptability of these rhythms and their coupling. The purpose of this study was to investigate the relationship between steady state locomotor-respiratory coordination dynamics and oxygen consumption [Formula: see text] of the movement by varying walking stride frequency from preferred. Twelve male participants walked on a treadmill at a self-selected speed. Stride frequency was varied from -20 to +20% of preferred stride frequency (PSF) while respiratory airflow, gas exchange variables, and stride kinematics were recorded. Discrete relative phase and return map techniques were used to evaluate the strength, stability, and variability of both frequency and phase couplings. Analysis of [Formula: see text] during steady-state walking showed a U-shaped response (P = 0.002) with a minimum at PSF and PSF - 10%. Locomotor-respiratory frequency coupling strength was not greater (P = 0.375) at PSF than any other stride frequency condition. The dominant coupling across all conditions was 2:1 with greater occurrences at the lower stride frequencies. Variability in coupling was the greatest during PSF, indicating an exploration of coupling strategies to search for the coupling frequency strategy with the least oxygen consumption. Contrary to the belief that increased strength of frequency coupling would decrease oxygen consumption; these results conclude that it is the increased variability of frequency coupling that results in lower oxygen consumption.
    Arbeitsphysiologie 06/2011; 112(3):929-40. · 2.66 Impact Factor
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    ABSTRACT: Previous reports on changes in postural control in adolescent idiopathic scoliosis (AIS) compared to healthy controls have been inconsistent. This may suggest center of pressure (COP) sway parameters are not sufficient for determining the ability to maintain quiet upright stance indicating more complex measures may be needed to examine postural control in AIS. The purpose of this investigation was to compare postural control between AIS of different severity levels and healthy controls using time-to-contact (TtC), the complexity index of multiscale entropy (C(r)), and COP sway parameters. Thirty-six AIS patients were classified as pre-bracing or pre-operative and compared to 10 healthy control subjects. Overall, the AIS patients showed significantly greater COP sway in mediolateral direction, but deficits with respect to the anteroposterior direction were only systematically identified with the time-to-contact and entropy measures. The multiscale entropy (C(r)) results indicate that those with AIS utilize a different control strategy from healthy controls in the mediolateral direction that is more constrained, less complex and less adaptable. AIS severity further reduced this adaptability in the anteroposterior direction. These results indicate it is necessary to examine both planes of motion when investigating postural control in AIS. Additionally, the application of the measures used to assess the nature of the postural control changes in AIS should also be considered.
    Gait & posture 05/2011; 34(1):13-8. · 2.58 Impact Factor
  • Joseph F Seay, Richard E A Van Emmerik, Joseph Hamill
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    ABSTRACT: Two-way repeated-measures analysis of variance. To assess pelvis and trunk three-dimensional segmental excursions and coordination differences during walking and running between runners with low back pain (LBP), runners with resolved LBP, and a control group with no history of LBP. Studies have documented differences in pelvis and trunk coordination between those with moderate to severe LBP during walking. Few studies document pelvis and trunk mechanics in those with low to moderate LBP and individuals who recover from LBP even though these individuals comprise 80% of LBP cases and are at increased risk for re-injury. Recreational runners walked and ran on a treadmill at speeds including 0.8 to 3.8 m/s at 0.5 m/s increments. Pelvis and trunk kinematic data were collected during the last 20 s of each stage. Coordination analysis quantified the portion of gait cycle each group spent in trunk only motion, pelvis-only motion, in-phase, and antiphase relationships. During walking, the LBP group spent more of the gait cycle in-phase in the frontal plane (P = 0.030). During running, the LBP group showed greater pelvis axial rotation than the control group (P = 0.014) and spent more of the gait cycle in-phase in the transverse plane (P = 0.019). Also during running, the LBP (P = 0.035) and the resolved LBP (P = 0.037) groups demonstrated reduced antiphase coordination compared to controls. Coordination analysis demonstrates a reduction in relative motion between the pelvis and trunk despite low disability levels in our LBP group and no pain in our group with a history of LBP.
    Spine 02/2011; 36(16):E1070-9. · 2.16 Impact Factor
  • Source
    Portuguese Journal of Sport Sciences. 01/2011; 11(Suppl. 2).
  • Christopher L MacLean, Richard van Emmerik, Joseph Hamill
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    ABSTRACT: 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.
    Journal of applied biomechanics 11/2010; 26(4):390-9. · 1.26 Impact Factor
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    ABSTRACT: People with multiple sclerosis (MS) often report problems with balance, which may be most apparent during challenging postural tasks such as leaning or reaching, and when relying on non-visual sensory systems. An additional obstacle facing people with MS is a high incidence of symptomatic fatigue (>70%). The purpose of this study was to investigate the changes in balance during upright stance in individuals with mild-to-moderate disability due to MS under normal and restricted vision and different levels of self-reported fatigue. Limb loading asymmetry, sway and magnitude of postural shift in center of pressure, and time-to-contact the stability boundary of the center of mass and center of pressure were assessed during quiet standing and maximal lean and reach tasks. Compared to controls, people with MS displayed greater postural sway, greater loading asymmetry, and shorter time-to-contact during quiet standing. In the postural perturbation tasks the MS group had smaller postural shifts and reduced stability compared to controls in the direction perpendicular to the lean and reach. Limiting vision increased loading asymmetry during quiet standing and postural instability during backward lean in the MS group. Inducing additional fatigue in the MS group did affect postural control in the more challenging balance conditions but had no impact during quiet upright standing. The results of this study indicate subtle changes in postural control during standing in people with mild-to-moderate impairments due to MS.
    Gait & posture 10/2010; 32(4):608-14. · 2.58 Impact Factor

Publication Stats

2k Citations
231.94 Total Impact Points

Institutions

  • 1996–2014
    • University of Massachusetts Amherst
      • Department of Kinesiology
      Amherst Center, Massachusetts, United States
  • 2011
    • Washington University in St. Louis
      • Program in Physical Therapy
      San Luis, Missouri, United States
  • 2008–2011
    • Purdue University
      • Department of Health and Kinesiology
      West Lafayette, IN, United States
    • Vancouver Island University
      Vancouver, British Columbia, Canada
    • Cardiff Metropolitan University
      • Cardiff School of Sport
      Cardiff, WLS, United Kingdom
  • 2000
    • Boston University
      • College of Health and Rehabilitation Sciences: Sargent College
      Boston, MA, United States
  • 1993–1996
    • VU University Amsterdam
      • • Department of Neurology
      • • Faculty of Human Movement Sciences
      Amsterdamo, North Holland, Netherlands
  • 1989–1996
    • University of Illinois, Urbana-Champaign
      • Department of Psychology
      Urbana, Illinois, United States
  • 1994
    • VU University Medical Center
      Amsterdamo, North Holland, Netherlands