Showing papers in "Human Movement Science in 1999"

TL;DR: In this article, the clinical performance characteristics of seven optical-based and one electromagnetic-based biomechanical measurement system were evaluated in a 3 m long volume, and the results indicated that five of the seven optical systems produced less than 2.0 mm RMS errors when measuring fully visible moving markers, and typically less that 1.0mm RMS error when measuring the stationary marker.

TL;DR: The authors examined the generalizability of the learning advantages produced by instructions that induce an external relative to an internal focus of attention, and found that the learning benefits of an external attentional focus seem to generalize to the feedback given to the learner.

TL;DR: Studies from the laboratory have demonstrated that, even for very rapid aiming movements, the characteristics of the movement trajectory change with the availability of visual information about the position of the limb and the target during the movement.

TL;DR: In this article, two groups of participants had to make very light tactile contact with an adjacent pliable surface while standing with their eyes closed, and the tactile contact was merely the result of extending the right forearm.

TL;DR: A 71 year old hypokinetic woman with PD is illustrated who demonstrated normalisation of key kinematic and spatiotemporal variables of gait when provided with visual cues at peak-dose of the medication cycle, despite persistent abnormalities in gait kinetics.

TL;DR: This paper examines possible interactions between the specialized structures for visuomotor transformation and the internal model that adapts prehension to its goals.

TL;DR: In this article, the influence of increasing load carriage on the gait of 10 military subjects was assessed under four conditions (unloaded barefoot, and in issue boots: unloaded, 20 and 40 kg loads).

TL;DR: In this article, the authors compared walking and running constrained to one speed (2.24 m/s) and the average of preferred walking-and running stride frequency, using phase plots, relative phase and variability analysis.

TL;DR: A technique is proposed to determine a correction factor which can be applied to gait data to correct for mal-alignment in conventional models of joint rotation angles arising from mis-placement of thigh markers.

TL;DR: Results show that the use of a full body kinematic model gives a better representation of the CM than does a fixed point in the pelvis, especially in pathological gait patterns.

TL;DR: The three-dimensional motions of the pelvis and lumbar spine in walking were measured, in 20 normal adult males, using “Vicon” optoelectronic system, with reflective targets attached to lightweight rigs over the thoracolumbar junction and upper sacrum.

TL;DR: A gait score was developed to indicate the overall assessment of the kinematic and kinetic gait measures by the principal component models and it was shown to agree with the clinical status as measured by the Knee Society Score.

TL;DR: The method is based on a biomechanical model of sway movements in quiet standing, according to which the horizontal acceleration of the COM is approximately proportional to the COM–COP difference.

TL;DR: For H-reflexes, significant differences between the two bimanual conditions were observed, suggesting differences in levels of excitability of the Ia afferent pathway, and motor-evoked potentials were larger in the antiphase condition than in the inphase condition.

TL;DR: In this article, the relative phase φ rel between angular motion of ankles and hips was analyzed and two preferred patterns emerged; close to in-phase (φ rel ǫ≈ 0°) and close to anti-phase(φ rea − 180°).

TL;DR: The authors found that children with developmental coordination disorder were more disadvantaged by invalid cues compared with controls, regardless of stimulus onset asynchrony, SOA; this finding was consistent with a deficit in the disengage operation of directing covert attention.

TL;DR: The timing of repetitive movements was assessed in a callosotomy patient under unimanual and bimanual conditions and the results suggest that motor commands from the two hemispheres are integrated subcortically.

TL;DR: Increased muscle tension provided a more stable base, producing increased stiffness, and the resonant frequencies of wand marker systems found to be typically 23–51 Hz, depending on the mass of the marker.

TL;DR: In this paper, the authors investigated the effects of preferred stroke rate and practice on metabolic variables, ratings of perceived exertion (RPE) and movement control of a rowing ergometer.

TL;DR: In this article, the effects of speed variation on the joint kinematic characteristics during multisegment reaching movements were examined, which revealed that neither the joint angle selection nor amplitude of the selected angle motions was significantly influenced by the speed variation, neither the time-scaling effect nor the symmetry of velocity profile was present, and a faster speed induced a steeper rate (time-scaled) for the primary descending/ascending but a greater fraction of total time for accelerating phase where the velocity and acceleration are in the same direction.

TL;DR: An eye targeting task was employed to investigate saccadic bias and endpoint variability as a function of target size and configuration, and movement amplitude, and the Muller–Lyer (ML) illusion was used to create illusory target endpoints.

TL;DR: In this paper, the development of both intralimb and interlimb coordination in fullterm and low-risk preterm infants was examined by recording spontaneous kicking at 4 weekly intervals from 4 to 24 weeks of age.

TL;DR: In this paper, the authors consider the problem of how the psychomotor system translates a stable motor memory into an invariant spatial output within an infinitely variable biomechanical and environmental context.

TL;DR: In this article, it is argued that by studying coordination dynamics at both the potential function and coupled oscillators, new insights into the way in which control parameters influence pattern dynamics may be obtained.

TL;DR: An explicit relation among control variables to the two joints is suggested as the foundation of a simple synergy whose purpose is to preserve control over the trajectory of the limb's endpoint in the presence of joint coupling.

TL;DR: Data is interpreted as consequences of the emergence of two synergies: (a) Pointing with a non-redundant set of the elbow and shoulder joints; and (b) keeping wrist position constant, which is based on a structural unit that includes all the major arm joints.

TL;DR: In this paper, eight right-handed participants performed a bilateral circle tracing task in symmetric or asymmetric patterns in synchrony with an auditory metronome and a visual display at, or comfortably below, each participant's transition frequency.

TL;DR: A distinct pattern of trunk kinematics during gait was found in this study and was used to identify the critical trunkKinematic events which occur during walking.

TL;DR: In this paper, the authors investigated bi-manual pointing movement towards a common target and hypothesised that if (parts of) bi-MANUAL movements are planned as one functional unit, then there should be significant correlations between the movement parameters of each hand.

TL;DR: In this paper, the authors investigated the effect of postural constraints on the performance of climbing reachings in two different postural conditions (easy and complex) towards holds of various depths (0.8, 2 and 5 cm).