Biomedical subjects

N Vuillerme

Publications and source records attributed to N Vuillerme.

8 recordsLinked to original sources

PubMed2006

Do ankle foot orthoses modify postural control during bipedal quiet standing following a localized fatigue of the ankle muscles?

The purpose of the present experiment was to investigate the effects of wearing ankle foot orthoses (AFO) on postural control during bipedal quiet standing following a localized fatigue of the ankle muscles. To this aim, eight young healthy subjects were asked to stand upright as immobile as possible with and without AFO in two conditions of non-fatigue and fatigue of the ankle muscles. The center of foot pressure displacements (CoP) were recorded using a force platform. Larger CoP displacements in the fatigue than non-fatigue condition were observed without AFO along both the medio-lateral and antero-posterior axes. Interestingly, with AFO, these destabilizing effects were not observed along the medio-lateral axis. Altogether, the present findings suggested that the AFO allowed the subjects to limit the postural perturbation induced by a localized fatigue of the ankle muscles during bipedal quiet standing.

Adult↗

PubMed2006

[Cervicocephalic relocation test: a study of performance stability].

OBJECTIVE: The purpose of the present experiment was to determine the reliability of the cervicocephalic relocation test (CRT). METHODOLOGY: Thirteen young healthy adults were recruited to undergo a CRT test-retest. The test-retest reliability was determined by repeatedly measuring CR to a neutral position after active movement, with trials approximately 1 hour apart. Each CRT involved 20 CRs to a natural head position, 10 repositioning after right head rotation, and 10 repositioning after left head rotation (with the order of rotation sides randomized). The performance score for each subject for each CRT was the mean of the errors made during the 20 relocations (in degrees). STUDY RESULTS: The mean rate of error of the first and second trials was 3.2+/-1.1 degrees and 2.9+/-0.9 degrees, respectively. The intra class correlation coefficient was 0.81, and the standard error of measurement 0.90 degrees. CONCLUSION: CRT testing supports evidence of reliable cervicocephalic performance stability in healthy young adults. CRT shows promise as a relevant tool of assessment in head and neck proprioception.

Adult↗

PubMed2005

[Prediction of falls with performance on Timed "Up-and-Go" and one-leg-balance tests and additional cognitive tasks].

OBJECTIVE: This study aimed to determine whether ordinary clinical performance on the timed "up-and-go" and one-leg-balance tests varied with additional cognitive tasks and the predictive value of this combination for future falls. METHODOLOGY: The sample comprised 95 women with osteoporosis who lived independently in the community and were older than 70 years (mean 73.4+/-1.7 years) who were randomized to perform the timed "up-and-go" (TUG) and one-leg-balance (OLB) tests. The tests were performed with or without an additional cognitive task (math task involving subtraction by 2 s or 5 s or addition by 3 s). RESULTS: For both TUG and OLB, performance decreased in the dual-task condition (P<0.05) but did not differ in older women with and without a history of falling, whatever the test, and with or without an additional cognitive load. CONCLUSION: Performance on the TUG and OLB tests was less efficient when patients simultaneously performed a cognitive task. Performance on these tests, without or with cognitive tasks, did not predict falls in a sample of women who lived independently.

Accidental Falls↗

PubMed2002

Effects of lower limbs muscular fatigue on anticipatory postural adjustments during arm motions in humans.

BACKGROUND: The purpose of the present experiment was to examine the effects of lower limbs muscular fatigue on the anticipatory postural adjustments during a voluntary arm raising movement. METHODS: Eight adult males (mean age 29+/-6 years) voluntarily participated to the experiment. Subjects' task consisted in performing an unilateral ante-flexion of the right arm over 90 deg, holding a 500 g weight, once having stabilized their upright posture. A similar movement execution was required. Measurements were made in a no-fatigue situation and under a high level of fatigue of lower limbs. Surface EMG of four postural muscles (the ipsilateral and contralateral Gastrocnemius and the ipsilateral and contralateral Semitendinosus) and of one muscle involved in the arm raising (the Anterior Deltoïdeus of the right arm) was recorded. Body sway was also monitored using a force platform. RESULTS: With fatigue, quantitative EMG analysis showed a decrease of the ipsilateral Semitendinosus activity whereas the temporal EMG analysis showed an increase of its latency with respect to movement onset. CONCLUSIONS: These data suggested a functional adaptation resulting in an invariance of global anticipatory postural adjustments for the two conditions of no-fatigue and fatigue and ensuring an adequate execution of the movement.

Adaptation, Physiological↗

PubMed2001

The effect of expertise in gymnastics on proprioceptive sensory integration in human subjects.

The ability of experts in motor skills requiring a fine postural control to keep a stable upright posture while facing the task of reinserting proprioceptive information was investigated. Seven expert gymnasts and seven experts in other non-gymnastics sports were asked to stand as immobile as possible in two conditions of vision and no-vision. Within a trial, ankle proprioceptive input was modified by means of tendon vibration of both antagonistic ankle muscles. Center of foot pressure (COP) displacements were recorded using a force platform. Contrasting with the non-gymnasts, the gymnasts were able to rapidly take advantage of the reinsertion of proprioceptive information to decrease their COP displacements. These results suggest that the efficiency of the integration process leading to the reweighting of sensory information can be significantly improved through a specific training.

Adult↗

PubMed2001

Can vision compensate for a lower limbs muscular fatigue for controlling posture in humans?

The purpose of the present experiment was to investigate the effect of vision on postural control following a lower limbs muscular fatigue. Ten adult males were asked to maintain a single leg upright posture as immobile as possible in two conditions of no-fatigue and fatigue of the calf muscles. This muscles fatigue was achieved by standing on the toes until exhaustion. Within a trial, vision was suppressed or reinserted by eyes closure or opening. Center of foot pressure displacements were recorded using a force platform. Results showed that the availability of vision allowed the subjects to immediately cope with the destabilizing effect induced by muscular fatigue.

Adaptation, Physiological↗

PubMed2001

The effect of expertise in gymnastics on postural control.

The goal of this paper was (1) to investigate if gymnasts have a more stable standing posture than experts in other sports, and (2) to determine how much gymnasts are affected by the removal of vision in different postural tasks. Six expert gymnasts and six experts in other non-gymnastic sports were asked to maintain balance in three standing postures of increasing difficulty: bipedal, unipedal, and unipedal + unstable support (i.e. 7 cm thick foam surface). Each posture was tested successively with and without vision. Based on the displacement of the center of pressure (range and mean average speed), the results showed that when visual cues were available, postural sway increased with the difficulty of the task, but both groups had comparable performance in all the tasks. When vision was removed, although both groups demonstrated larger postural sway in the unipedal tasks, this effect was less accentuated for the gymnasts. We concluded that gymnasts are able to use the remaining sensory modalities to compensate for the lack of vision in unstable postures.

Adult↗

PubMed2000

Effects of a reaction time task on postural control in humans.

The purpose of the present experiments was to investigate the effects of a reaction time (RT) task on postural control, during and following the execution. Three different RT tasks consisting in verbal responses to visual and auditory stimuli were supposed to require different demands on cognitive resources. There was also a control condition in which no concurrent task was required. Postural control was assessed using a force platform. Results showed that (1) center of foot pressure (COP) displacements significantly decreased while concurrently performing the RT tasks, (2) this effect lasted for at least 10 s following the secondary task performance and (3) COP displacements decreased similarly, whatever the attentional requirements of the secondary task.

Adult↗