- Human Motor Behavior, Sensory Neuroscience, Motor Development, Infancy, Performance Analysis, Electrophysiology, and 29 moreAffordances, Human Movement Science, Electroencephalography, Visual perception (Psychology), Psychophysics, Motor Learning, Visual Working Memory, Visual attention, Brain Imaging, Mirror Neurons, Perception-Action, Visual Neuroscience, Ecological Psychology, Gait Biomechanics, Human Perception and Performance, Locomotion, Proprioception, Posture, Perception (Psychology), Eye tracking, Visual perception, Psychophysics of vision, Philosophy of Neuroscience, Implicit learning, Motor Control, Neural Control of Movement, Visual Search, Multisensory perception, and Tactile Perceptionedit
BACKGROUND: Individuals with a perception of their fragile health can potentiate the fear of COVID-19. AIM: We investigated the relationship between perceived functional capacity and fear of falls with fear of COVID-19 in older adults.... more
BACKGROUND: Individuals with a perception of their fragile health can potentiate the fear of COVID-19. AIM: We investigated the relationship between perceived functional capacity and fear of falls with fear of COVID-19 in older adults. METHOD: Thirty older adults (60-75 years) participated in this study. We applied two questionnaires to assess functional capacity: the Independence in Activities of Daily Living and the Instrumental Activities of Daily Living Scale. We also administered two questionnaires for fear of falling: the Activities-Specific Balance Confidence Scale and Falls Efficacy Scale International. Finally, we used the Fear of COVID-19 Scale. RESULTS: The results showed a significant correlation between fear of COVID-19 and the ABC Scale (r = -0.548, p = 0.002) and FES-I (r = 0.466; p = 0.009). Multiple linear regression analysis showed that the ABS Scale was the only predictor of fear of COVID-19 (p = 0.004). CONCLUSION: Fear of COVID-19 was related to a worsening perc...
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During locomotion, we respond to environmental and task changes by adjusting steps length and width. Different protocols involving stepping on targets and obstacle avoidance suggest the involvement of cortical and subcortical pathways in... more
During locomotion, we respond to environmental and task changes by adjusting steps length and width. Different protocols involving stepping on targets and obstacle avoidance suggest the involvement of cortical and subcortical pathways in these online adjustments. The addition of a concomitant cognitive task (CT) can affect these online corrections depending on the neural pathway used. Thereby, we investigated the online adjustment using a target stepping task and a planar obstacle avoidance task in young adults and analyzed the effect of a CT on these adjustments. Twenty young adults executed two blocks of trials of walking performing the target task (TT) and obstacle avoidance task (OAT), with and without a concomitant CT. In the TT, participants stepped on a target projected on the ground, whereas in the OAT they avoided stepping on an obstacle projected on the ground. The target/obstacle could change its original position in four directions at contralateral foot contact on the gr...
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The force variability of the plantar flexor muscles (PFM) appears to be directly related to the control of upright standing. Nevertheless, this association is still uncertain in older adults. This study aimed to evaluate the relationship... more
The force variability of the plantar flexor muscles (PFM) appears to be directly related to the control of upright standing. Nevertheless, this association is still uncertain in older adults. This study aimed to evaluate the relationship between PFM force variability and postural sway in the upright standing in older women. Forty older women performed submaximal plantar flexion movements measured by force transducers coupled to an experimental chair. They performed this task during three sets of 20 s at 5% and 10% of their maximum voluntary isometric contraction with and without the aid of visual feedback of the force produced. The volunteers then stood barefoot, with eyes closed and feet parallel on a force platform, which allowed the measurement of the center of pressure displacement in the anteroposterior direction. The results did not indicate a significant association between force variability of the PFMs and postural sway in older women. It can be inferred that the force varia...
Research Interests: Engineering, Skeletal muscle biology, Aging, Medicine, Physical Medicine and Rehabilitation, and 15 moreHuman Movement Science, Humans, Female, Posture, Aged, Middle Aged, Sensory Feedback, Foot, Isometric Exercise, Postural Balance, Barefoot, Isometric Contraction, Force Platform, Psychology and Cognitive Sciences, and Medical and Health Sciences
Our purpose was to verify the effects of the use of the anchors on postural control after the fatigue of the plantar flexor muscles in young and older adults. They stood barefoot, with their eyes closed in four conditions combining the... more
Our purpose was to verify the effects of the use of the anchors on postural control after the fatigue of the plantar flexor muscles in young and older adults. They stood barefoot, with their eyes closed in four conditions combining the use of the anchors and the fatigue. When using the anchors, participants held one cable in each hand and kept the cable taut without removing the loads (125 g) from the ground. The fatigue protocol consisted of performing a single series of bilateral plantar flexion movements. The fatigue protocol increased postural sway in both groups. Both groups reduced postural sway with the anchors, but this effect was independent of fatigue. We conclude that the anchors contributed to the reduction of postural sway in young and older adults, but they were unable to compensate for the disturbing effect in postural control created by fatigue of the plantar flexor muscles.
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Typically, falls in older adults occur when 2 tasks are performed simultaneously, due to the increased motor demand required to maintain stability and attention to perform the other task. The... more
Typically, falls in older adults occur when 2 tasks are performed simultaneously, due to the increased motor demand required to maintain stability and attention to perform the other task. The authors' purpose was to investigate walking while grasping, transporting, and placing a dowel on a predetermined target while manipulating difficulty levels of the manual task. Faller and nonfaller older adults performed a walking block (manual tasks combined with gait) and a stationary block (upright stance combined with manual tasks). The manual task involved grasping, transporting, and placing the dowel over a target. The results showed that fallers underperformed when compared with nonfallers in the task of placing the dowel over the target. The main difference observed between the groups was found in the condition that required allocation of attention between tasks and greater accuracy in the final placement of the object. Fallers showed gait stability similar to the nonfallers, but fallers were less accurate than nonfallers in the object placement task, especially for the highest level of difficulty. Thus, fallers seem to use a stability-first strategy. Fallers had problems in executing the manual tasks, which suggests a more global change in motor behavior rather than specific changes to balance control.
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There are different ways to add haptic input during walking which may affect walking balance. This study compared the use of two different haptic tools (rigid railing and haptic anchors) and investigated whether any effects on walking... more
There are different ways to add haptic input during walking which may affect walking balance. This study compared the use of two different haptic tools (rigid railing and haptic anchors) and investigated whether any effects on walking were the result of the added sensory input and/or the posture generated when using those tools. Data from 28 young healthy adults were collected using the Mobility Lab inertial sensor system (APDM, Oregon, USA). Participants walked with and without both haptic tools and while pretending to use both haptic tools (placebo trials), with eyes opened and eyes closed. Using the tools or pretending to use both tools decreased normalized stride velocity (p < .001-0.008) and peak medial-lateral (ML) trunk velocity (p < .001-0.001). Normalized stride velocity was slower when actually using the railing compared to placebo railing trials (p = .006). Using the anchors resulted in lower peak ML trunk velocity than the railing (p = .002). The anchors had lower ...
Research Interests: Computer Science, Adolescent, Medicine, Physical Medicine and Rehabilitation, Humans, and 13 morePlacebo, Walking, Female, Male, Young Adult, Adult, Haptic Technology, Touch Perception, Postural Balance, Trunk, Biomechanical Phenomena, Psychology and Cognitive Sciences, and Medical and Health Sciences
The main aim of this study was to verify the relationship between the classification of coaches and actual performance in field tests that measure the kicking performance in young soccer players, using the K--means clustering technique.... more
The main aim of this study was to verify the relationship between the classification of coaches and actual performance in field tests that measure the kicking performance in young soccer players, using the K--means clustering technique. Twenty--three U--14 players performed eight tests to measure their kicking performance. Four experienced coaches provided a rating for each player as follows: 1--poor, 2--below average, 3--average, 4--very good, 5-excellent as related to three parameters (i.e. accuracy, power and ability to put spin on the ball). The scores interval established from k--means cluster metric was useful to originating five groups of performance level, since ANOVA revealed significant differences between clusters generated (p < 0.01). Accuracy seems to be moderately predicted by the penalty kick, free kick, kicking the ball rolling and Wall Volley Test (0.44 ≤ r ≤ 0.56), while the ability to put spin on the ball can be measured by the free kick and the corner kick tes...
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The purpose of the present study was to analyze the contribution of both exproprioceptive visual information and seat height in the control of stand-to-sit movement in young and older adults. Twelve older and 11 young individuals were... more
The purpose of the present study was to analyze the contribution of both exproprioceptive visual information and seat height in the control of stand-to-sit movement in young and older adults. Twelve older and 11 young individuals were invited to sit down on a chair under two seat heights (100% and 80% of the knee-ground distance) and under two visual conditions (with and without the availability of exproprioceptive visual information). Participants wore special goggles that reduced the size of the lower visual field. Participants performed the stand-to-sit movement with their feet positioned on a forceplate. The results allowed for the conclusion that the exproprioceptive visual information availability affected differently the way young and older adults control the stand-to-sit movement. On the other hand, seat height manipulation resulted in similar strategies by young and older individuals. Yet, older individuals exhibited a more conservative behavior than young adults while perf...
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Background. Depending on the dimensions of a hole, the characteristics of the walking surface, and the position of the hole relative to normal walking, individuals may need to step into the hole with the dominant or non-dominant limb.... more
Background. Depending on the dimensions of a hole, the characteristics of the walking surface, and the position of the hole relative to normal walking, individuals may need to step into the hole with the dominant or non-dominant limb. Aim. We investigated the effect of the lower limb dominance in walking adaptations in the presence of a hole on the ground. Methods: Twenty young adults walked and stepped into a hole positioned in the middle of the pathway using the dominant and non-dominant lower limbs. Results. For the trailing limb, the impulses were not affected by the lower limb dominance, but for the leading limb, the non-dominant leg increased the braking and propulsive impulses compared to the dominant leg. On the other hand, toe-off velocity increased when the non-dominant leg was used as trailing and leading limbs. Stride speed increased when the non-dominant leg was the trailing limb. Interpretation. Our results were consistent with asymmetrical behavior between dominant an...
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Dynamic balance keeps the vertical projection of the center of mass within the base of support while walking. Dynamic balance tests are used to predict the risks of falls and eventual falls. The psychometric properties of most dynamic... more
Dynamic balance keeps the vertical projection of the center of mass within the base of support while walking. Dynamic balance tests are used to predict the risks of falls and eventual falls. The psychometric properties of most dynamic balance tests are unsatisfactory and do not comprise an actual loss of balance while walking. Using beam walking distance as a measure of dynamic balance, the BEAM consortium will determine the psychometric properties, lifespan and patient reference values, the relationship with selected "dynamic balance tests," and the accuracy of beam walking distance to predict falls. This cross-sectional observational study will examine healthy adults in 7 decades (n = 432) at 4 centers. Center 5 will examine patients (n = 100) diagnosed with Parkinson's disease, multiple sclerosis, stroke, and balance disorders. In test 1, all participants will be measured for demographics, medical history, muscle strength, gait, static balance, dynamic balance using...
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Using conventional tDCS over the temporo-parietal junction (TPJ) we previously reported that it is possible to manipulate subjective visual vertical (SVV) and postural control. We also demonstrated that high-definition tDCS (HD-tDCS) can... more
Using conventional tDCS over the temporo-parietal junction (TPJ) we previously reported that it is possible to manipulate subjective visual vertical (SVV) and postural control. We also demonstrated that high-definition tDCS (HD-tDCS) can achieve substantially greater cortical stimulation focality than conventional tDCS. However, it is critical to establish dose-response effects using well-defined protocols with relevance to clinically meaningful applications. To conduct three pilot studies investigating polarity and intensity-dependent effects of HD-tDCS over the right TPJ on behavioral and physiological outcome measures in healthy subjects. We additionally aimed to establish the feasibility, safety, and tolerability of this stimulation protocol. We designed three separate randomized, double-blind, crossover phase I clinical trials in different cohorts of healthy adults using the same stimulation protocol. The primary outcome measure for trial 1 was SVV; trial 2, weight-bearing asym...
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The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to... more
The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to measure (300 Hz) ball velocity (V), foot velocity (V), V/Vratio, last stride length, and distance between the support foot and the ball. Simultaneously, a two-dimensional procedure was also conducted to compute (60 Hz) the mean radial error, bivariate variable error, and accuracy. Possible age-related differences were assessed through one-way analysis of variance and magnitude-based inferences. Ball velocity increased by 103% (p < .001, η = .39) from the U11 age group (48.54 ± 8.31 km/hr) to the U20 age group (98.74 ± 16.35 km/hr). Foot velocity presented a 59% increase (p < .001, η = .32) from the U11 age group (49.08 ± 5.16 km/hr) to U20 (78.24 ± 9.49 km/hr). This finding was due to improvement in the quality of foot-ball impact (V/Vratio) f...
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Objective: The aim of the present study was to evaluate the influence of a balance training program on the semi-static balance of elderly persons by comparing a supervised group with individual home-based application. Method: A blinded... more
Objective: The aim of the present study was to evaluate the influence of a balance training program on the semi-static balance of elderly persons by comparing a supervised group with individual home-based application. Method: A blinded randomized controlled multi-arm trial was conducted. The elderly individuals were randomized into: Supervised Group (SG; n=18); Domiciliary Group (DG; n=20) and Control Group (CG; n=18). The SG and DG participated in twice weekly training sessions for 10 weeks. A posturography evaluation was performed based on velocity, anterior-posterior (AP) and medial-lateral (ML) medial amplitude variables in firm surface with eyes open (FSEO) and closed (FSEC), tandem stance with eyes open (Tandem EO) and closed (Tandem EC), and single-leg stance (SL) situations. Two-way ANOVA and Tukey's post-hoc were used for parametric data, the Friedman and Wilcoxon post-hoc tests were used for intragroup analysis and the Kruskal-Wallis and Mann-Whitney post-hoc tests wer...
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Older adults have a greater incidence of falls, and risk of falls will increase when combining two motor tasks. Thus, it is interesting to investigate the effect of fall history on motor performance in older adults when combining walking... more
Older adults have a greater incidence of falls, and risk of falls will increase when combining two motor tasks. Thus, it is interesting to investigate the effect of fall history on motor performance in older adults when combining walking with another task such as grasping an object. The aim of this study was to investigate the combined task of walking and prehension with different levels of manual task difficulty in older adults with and without a history of falls. Thirty older adults participated in this study; groups were designated as fallers (n=15) and non-fallers (n=15). Participants were asked to reach-to-grasp a dowel during quiet standing and during walking. Level of manual task difficulty was manipulated by the type of dowel support and obstacles located at different distances to the sides of the dowel. Fall history influenced the performance of this combined task for the most difficult manual conditions. Fallers were able to be identified due to differences in the grasping...
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Objective: Converging evidence supporting an effect of transcranial direct current stimulation (tDCS) on postural control and human verticality perception highlights this strategy as promising for post-stroke rehabilitation. We have... more
Objective: Converging evidence supporting an effect of transcranial direct current stimulation (tDCS) on postural control and human verticality perception highlights this strategy as promising for post-stroke rehabilitation. We have previously demonstrated polarity-dependent effects of high-definition tDCS (HD-tDCS) on weight-bearing asymmetry. However, there is no investigation regarding the time-course of effects on postural control induced by HD-tDCS protocols. Thus, we performed a nonlinear time series analysis focusing on the entropy of the ground reaction force as a secondary investigation of our randomized, double-blind, placebo-controlled, crossover clinical trial. Materials and Methods: Twenty healthy right-handed young adults received the following conditions (random order, separate days); anode center HD-tDCS, cathode center HD-tDCS or sham HD-tDCS at 1, 2, and 3 mA over the right temporo-parietal junction (TPJ). Using summarized time series of transfer entropy, we evalua...
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This mini-review focuses on intrinsic risk factors for falls, particularly the changes in motor behavior of faller older adults. Our purpose is to present evidence that faller older adults exhibit motor behavior changes beyond the... more
This mini-review focuses on intrinsic risk factors for falls, particularly the changes in motor behavior of faller older adults. Our purpose is to present evidence that faller older adults exhibit motor behavior changes beyond the typically investigated standing and walking tasks. We showed initially that postural control alterations with more prominent differences for fallers than non-fallers seem to depend on postural demands, availability of sensory information, and tasks performed concomitantly with the balancing task. We also provided evidence that walking speed is the most consistent aspect to differentiate fallers from non-fallers. This reduction in walking speed may be a strategy to improve gait stability to avoid a fall. More recent studies have shown that fallers presented modifications in the control of the prehension movement. These changes suggest that fallers have changes in movement categories other than balancing and walking, suggesting that fallers’ difficulties are...
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BACKGROUND Asymmetrical load-carrying while walking requires modifications in joint forces to compensate the extra mass and ensure body stability, particularly when the environment is uneven, such as with a curb. Carrying a bag with one... more
BACKGROUND Asymmetrical load-carrying while walking requires modifications in joint forces to compensate the extra mass and ensure body stability, particularly when the environment is uneven, such as with a curb. Carrying a bag with one hand (dominant or non-dominant) may constrain the movement of the arm, altering the interlimb coordination of the upper limbs. Prior studies did not show changes in interlimb coordination when a light load was attached to the wrist, but the use of a bag to carry the load can be potentially disturbing since exaggerated movements of the bags may compromise balance. In this case, changes in interlimb coordination would be expected to minimize bag movements. However, it is not clear if these changes in interlimb coordination would be sufficient to affect the curb negotiation task. RESEARCH QUESTION We investigated the effect of asymmetric load-carrying using different bag types with the dominant and non-dominant hands on upper limb coordination and walking adaptations in a curb negotiation task in young adults. METHODS Seventeen young adults walked and stepped down a curb while carrying a bag with 7% of their body mass. The experimental conditions were to walk without the bag, carrying the bag (with and without strap) using the dominant and non-dominant hand. RESULTS Carrying the bag reduced the anti-phase pattern and increased the right or left shoulder phases, depending on the side used to carry the bag. It means that the limb that carried the load almost did not move while stepping down the curb. Load transportation did not influence foot-curb negotiation variables. SIGNIFICANCE Our study indicates that a mild load and the bag influenced the interlimb coordination of the upper limbs. Despite that, young adults compensated for the disturbance caused by the load carriage and did not compromise the curb negotiation task.
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O objetivo do presente estudo foi avaliar cinematicamente possíveis alterações que possam ocorrer na topologia do movimento de andar para frente (AF) e andar para trás (AT). Nove participantes idosos (GI) e nove jovens (GJ) foram... more
O objetivo do presente estudo foi avaliar cinematicamente possíveis alterações que possam ocorrer na topologia do movimento de andar para frente (AF) e andar para trás (AT). Nove participantes idosos (GI) e nove jovens (GJ) foram convidados a participar deste estudo. Os participantes foram filmados no plano sagital nas tarefas de AF e AT. A análise dos resultados permitiu observar que o comprimento relativo da passada foi maior para o GJ e maior no AF, enquanto a duração da passada não variou em função da idade nem da tarefa. A velocidade da passada (VP) foi maior no AF e maior para o GJ. O GI diminuiu a VP no AT em relação ao GJ. A análise dos retratos de fase (RF) do joelho e ângulos de fase da coxa e perna permitiu identificar que no AT há uma preferência pelo sistema coxa-perna de oscilar na mesma direção ao longo de toda a passada. Concluímos que indivíduos idosos têm um comprometimento maior para realizar atividades motoras não habituais, como AT. Além disso, no AT ocorre uma ...
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The present study had two main purposes. The first purpose was to investigate the contribution of visual and somatosensory information to postural control in deaf children. The second purpose was to investigate the motor development of... more
The present study had two main purposes. The first purpose was to investigate the contribution of visual and somatosensory information to postural control in deaf children. The second purpose was to investigate the motor development of deaf children measured through the Motor Development Scale (MDS). Deaf and normal hearing children of the same chronological age were asked to stand on three different bases of support (single-limb, bipedal, and Romberg). For each base of support, the availability of visual information and the quality of somatosensory information manipulated by using a foam surface were combined. Children were also assessed through the MDS. Results related to postural control pointed out that deaf children exhibited a reduction on the time they stayed on the single-limb standing, especially for firm surface. Besides, the manipulation of visual information and the quality of somatosensory information diminished the time that participants stayed on both single-limb and ...
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This study investigated the effect of adding haptic information to the control of posture, as well as comparing the effect of both the "light touch" (LT) and "anchor system" (AS) paradigms on postural sway.... more
This study investigated the effect of adding haptic information to the control of posture, as well as comparing the effect of both the "light touch" (LT) and "anchor system" (AS) paradigms on postural sway. Additionally, it compared the effect of location and number of points of contact to the control of posture in young adults. The location consisted of using the anchors tied to the finger and held by the hands, and, for LT, the fingertip. For the number of points of contact, participants used two hands, and then separately the dominant hand, and the non-dominant hand, for both anchor and LT paradigms. Participants stood upright with feet-together and in tandem position while performing tasks that combined the use of anchors and LT, points of contact (hand grip and finger), and number of points of contact (two hands and one hand). In this study, the anchors consist of holding in each hand a flexible cable with the other end attached to the ground. The LT consist...
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RESUMO O sistema âncora é uma ferramenta não rígida que fornece informação háptica adicional, consistindo de dois cabos maleáveis com 125 g de massa repousando no solo, devendo-se segurar a outra extremidade com as mãos (âncora-mão).... more
RESUMO O sistema âncora é uma ferramenta não rígida que fornece informação háptica adicional, consistindo de dois cabos maleáveis com 125 g de massa repousando no solo, devendo-se segurar a outra extremidade com as mãos (âncora-mão). Considerando que o toque leve em diferentes partes do corpo reduz a oscilação corporal, é possível, da mesma forma, que o uso do sistema âncora em diferentes partes do corpo seja efetivo. Portanto, o objetivo deste estudo foi investigar o efeito do uso do sistema âncora em diferentes segmentos corporais sobre a oscilação corporal de idosos. Trinta idosos participaram do presente estudo. Eles ficaram na postura ereta com os pés na posição semi-tandem sobre uma plataforma de força para a obtenção do deslocamento do centro de pressão (CP). Cinco condições experimentais foram realizadas: sem âncora, âncora-mão, âncoras nas mãos presas com presilhas, âncoras nos antebraços presas com presilhas e âncoras nos ombros presas com presilhas. Os resultados mostrara...
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Although gait initiation from an upright posture has been extensively studied, little attention has been given to understanding gait initiation from a sitting posture. The purpose of the present study is to describe the changes in muscle... more
Although gait initiation from an upright posture has been extensively studied, little attention has been given to understanding gait initiation from a sitting posture. The purpose of the present study is to describe the changes in muscle activity during STW movement in comparison to STS movement. Green light cued individuals (N = 7) to initiate sit-to-walk (STW) movement whereas a red light cued them to perform sit-to-stand (STS) movement. Participants sat on an armless and backless seat with a mechanism for adjusting seat height (based on knee distance from the ground). They kept arms folded on the chest throughout the trial and were instructed to stand up as quickly as possible and to initiate gait with the right leg. Ten channels of EMG were recorded using surface electrodes over the belly of tibialis anterior (TA), medial gastrocnemius (GA), rectus femoris (RF), biceps femoris (BF), and erector spinae at L3-L4 location (ES). EMG signal was full wave rectified and digitally filtered using a fourth-order zero lag Butterworth filter with a cut-off frequency of 10 Hz. Six markers were placed on anatomical landmarks on the right side (5th metatarsal, heel, ankle, knee, hip and shoulder) and tracked by three OPTOTRAK units. A force plate was used under the seat to identify seat-off event. EMG data was aligned relative to the movement initiation (identified based on the anteroposterior velocity profile of the shoulder). EMG profiles for the STS movement (plus/minus one standard deviation) were used as baseline values. For the STW, deviations from this baseline values were identified and the latencies were calculated. The results indicated that for right and left TA, changes in muscle activity started before seat-off, which can be interpreted as an additional mechanism to help moving the body forward. For the muscle latencies, the one-way ANOVA with repeated measures (muscles) identified a main effect (F9,54 = 5.795, p = 0.006). Differences between left and right pairs of muscles were observed only for the GA (longer latency for the left than for the right side) due to differences in timing for the right and left push-offs. For the right side, changes in the TA, GA, and RF were followed by changes in the ES and later by changes in the BF. For the left side, changes in the TA were followed by changes in the RF and ES and later by changes in the GA and BF.
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This study assessed whether the use of an "anchor system" benefited older adults who performed a tandem walking task. Additionally, we tested the effects of practice with the anchor system during walking on trunk stability, in... more
This study assessed whether the use of an "anchor system" benefited older adults who performed a tandem walking task. Additionally, we tested the effects of practice with the anchor system during walking on trunk stability, in the frontal plane, of older adults. Forty-four older adults were randomly assigned to three groups: control group, 0g anchor group, and 125g anchor group. Individuals in each group performed a tandem walking task on the GaitRite system with an accelerometer placed on the cervical region. The participants in the 125g anchor group held, in each hand, a flexible cable with a light mass attached at the end of the cable, which rested on the ground. While the participants walked, they pulled on the cables just enough to keep them taut as the masses slid over the ground. The 0g anchor group held an anchor tool without any mass attached to the end portion. The results of this study demonstrated that the use of the anchor system contributed to the reduction o...
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The purpose of this study was to verify whether or not different levels of sensitivity and accuracy of force perception would be related to athletic experience and to verify whether or not accuracy depends on type of muscle groups used... more
The purpose of this study was to verify whether or not different levels of sensitivity and accuracy of force perception would be related to athletic experience and to verify whether or not accuracy depends on type of muscle groups used during different psychophysical tasks of force perception. Subjects with athletic experience (GA) and sedentaries (GS) produced and estimated magnitudes of force by: 1. pressing manually a dynamometer (DM); 2. arm lifting in a supine position (SU) and 3. leg pressing in a sitting position (LP). Results showed that GA and GS groups had different styles of force perception. The GS perceived magnitudes of weights closer to the real scale used in the LP task. The GA exhibited superconstancy during both SU and LP tasks. Underconstancy was common for both groups in the DM task. The GA tended to overestimate the terminal magnitudes of lifted weights in the SU and LP tasks. However, they were not very sensitive to changes of weights of low intensity.
The present study had two purposes: assess the effect of the anchor system on the postural control of older adults, and assess the effect of the systematic use of the anchor system on the postural control of older adults. Five older... more
The present study had two purposes: assess the effect of the anchor system on the postural control of older adults, and assess the effect of the systematic use of the anchor system on the postural control of older adults. Five older adults were invited to stand in a semi-tandem position with and without the use of an anchor system. For each block of practice trials using the anchor system, participants held, in each hand, a nylon rope attached to a 125g-anchor-weight. Participants were asked to keep each rope stretched and the anchor weight resting on the floor. Results pointed out that the anchor system reduced body sway measured through center of pressure displacements. However, when the older adults were tested in the transfer condition without the anchor system, the use of the anchor system did not result in any long lasting effect on their postural control.
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The purpose of this study was to use kinematic analysis to evaluate changes that take place in the movement topology of older individuals while walking forward (FW) and backward (BW). Nine older participants (OG) and nine young adults... more
The purpose of this study was to use kinematic analysis to evaluate changes that take place in the movement topology of older individuals while walking forward (FW) and backward (BW). Nine older participants (OG) and nine young adults (YG) participated in this study. Subjects were filmed from the sagital plane while FW and BW. Analysis of results permitted us to observe that relative stride length (RSL) for the YG was longer than for the OG. When we compared both tasks, we observed that RSL was longer for FW than BW. Stride duration was the same for both groups in both tasks. For the YG, stride velocity (SV) during the FW task was higher than for the BW task. The OG exhibited diminished SV in the BW task. The analysis of knee phase portraits (PPs) and phase angles permitted us to identify that, in the BW task, the thigh-shank systems oscillated in the same rotational direction during strides. Additionally, both groups modified their damping strategies, as observed in the knee PPs. T...
The purpose of this study was to verify whether or not mental retardation can be a constraint in the perception of space during tasks of dynamic orientation by individuals with mental retardation. Two different groups—fourteen individuals... more
The purpose of this study was to verify whether or not mental retardation can be a constraint in the perception of space during tasks of dynamic orientation by individuals with mental retardation. Two different groups—fourteen individuals with mental retardation (MR), and ten normal individuals (NN)—were requested to return to the departure point after walking in a straight line (L) and along two sides of a squared triangle (T). Distances varied in length from 5 to 24 meters. Monocular (MN) and haptic (HP) modes were tested. A power function was used to determine a fit between curves representing physical and produced (behavioral) distances. Also, relative errors of produced distance (REPD) and angle deviation (READ) were analyzed. In both experiments results showed underconstancy (psychophysical exponent below 1.0) for both groups in both conditions. The MR group showed larger angle deviations in both task trajectories. Significant differences between groups were found for the psyc...
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Typically, prehension and gait behaviors are studied separately. However, little is known about what changes occur in these motor skills when they are combined. We investigated and characterized motor performance during combined walking... more
Typically, prehension and gait behaviors are studied separately. However, little is known about what changes occur in these motor skills when they are combined. We investigated and characterized motor performance during combined walking and prehension at different levels of difficulty of the prehension task. Fifteen right-handed young adults were invited to walk at their self-selected pace and grasp a dowel as they walked. They also grasped the dowel in a stationary condition (upright stance). We combined conditions with/without obstacles and stable/unstable base for dowel prehension. Modifications in gait and prehension were identified when they were combined, especially for the most difficult prehension conditions. The grasping task caused an adaptation in gait because the participants preferred to adopt a more conservative strategy of increasing their dynamic stability during the approach phase and when grasping the dowel. Walking changed the prehension movement by reducing the r...
Research Interests: Engineering, Computer Science, Medicine, Physical Medicine and Rehabilitation, Human Movement Science, and 15 moreGait, Humans, Walking, Kinematics, Female, Male, Arm, Adult, Analysis of Variance, Time Factors, Hand, Wrist, Psychomotor Performance, Psychology and Cognitive Sciences, and Medical and Health Sciences
The purpose of this study was to investigate children&amp;amp;amp;#x27;s distance perception while walking blindfolded. Also, in order to measure differences at various distances, biomechanical parameters were assessed. Seven... more
The purpose of this study was to investigate children&amp;amp;amp;#x27;s distance perception while walking blindfolded. Also, in order to measure differences at various distances, biomechanical parameters were assessed. Seven children, aged 6 (CG), and 10 adults (AG) were asked ...
Prior studies suggest that infants with Down syndrome (DS) need more experience to acquire a similar relationship between visual information and body sway than infants without DS. However, it is unclear how adults with DS deal with visual... more
Prior studies suggest that infants with Down syndrome (DS) need more experience to acquire a similar relationship between visual information and body sway than infants without DS. However, it is unclear how adults with DS deal with visual information to control posture. To examine the coupling between visual information and body sway in adults with DS. Twenty adults with DS (25.8±4.0years) and twenty age- and sex-matched controls (25.6±4.0years) stood upright inside a "moving room" in two experimental conditions: continuous (room oscillated continuously at 0.1, 0.2, and 0.5Hz) and discrete (room moved forward or backward for a brief moment). Tridimensional body sway and moving room displacement data were registered. Individuals with DS coupled their body sway to the imposed visual stimulus, but showed higher position variability at frequencies other than the frequency of room movement (0.48cm) and lower coherence (0.80) than controls (0.40cm and 0.90, respectively). Adults...
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Research Interests:
Research Interests:
Research Interests:
This study assessed the contribution of the "anchor system's" haptic information to balance control during walking at two levels of difficulty. Seventeen young adults and seventeen older adults performed 20 randomized trials... more
This study assessed the contribution of the "anchor system's" haptic information to balance control during walking at two levels of difficulty. Seventeen young adults and seventeen older adults performed 20 randomized trials of tandem walking in a straight line, on level ground and on a slightly-raised balance beam, both with and without the use of the anchors. The anchor consists of two flexible cables, whose ends participants hold in each hand, to which weights (125 g) are attached at the opposing ends, and which rest on the ground. As the participants walk, they pull on the cables, dragging the anchors. Spatiotemporal gait variables (step speed and single- and double-support duration) were processed using retro-reflective markers on anatomical sites. An accelerometer positioned in the cervical region registered trunk acceleration. Walking on the balance beam increased single- and double-support duration and reduced step speed in older adults, which suggests that thi...
Research Interests:
Obstacle avoidance and object prehension occur regularly in real-world environments (walking up/down steps and opening a door). However, it is not known how walking and prehension change when there is an increase in the level of... more
Obstacle avoidance and object prehension occur regularly in real-world environments (walking up/down steps and opening a door). However, it is not known how walking and prehension change when there is an increase in the level of difficulty of the walking task. We investigated the changes in walking and reach-tograsp when performing these two motor skills concomitantly in the presence of an obstacle on the ground positioned in different locations in relation to the object-to-be-grasped. Fifteen young adults walked and grasped a dowel placed on a support with the obstacle positioned at the step before (N-1), during (N) and after (N + 1) the prehension task. The prehension task did not affect leading limb obstacle negotiation. Toe clearance and maximum toe elevation were lesser at obstacle position N + 1 than at obstacle position N-1 when combining grasping and obstacle-crossing task for the trailing limb. Step width increased in the presence of the obstacle-crossing task independent o...