BACKGROUND: Individuals with a perception of their fragile health can potentiate the fear of COVI... 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...
We investigated the effect of asymmetric load carrying using different bag types with the dominan... more We investigated the effect of asymmetric load carrying using different bag types with the dominant and non-dominant hands on upper limb coordination, walking adaptations, and stability control in a curbdescend task in older adults. Fourteen participants walked on a pathway with a 16-cm curb located in the middle. They walked without a load or asymmetrically carrying a load corresponding to 7% of their body mass. The weight was placed in two different bags (with and without strap) and carried by the dominant and non-dominant hands. The upper limb coordination analysis showed that the anti-phase pattern between right and left shoulder reduced considerably due to the almost motionless shoulder of the side carrying the load. The spatial-temporal walking parameters and curb negotiation variables were unaffected by load carriage. The margin of stability (MoS) was unchanged by load transportation in the AP direction. In the ML direction, taking the bag on the same side of the foot contacting the floor increased the MoS; however, when the load was incorporated into the COM model, the MoS did not differ anymore from the control condition. The changes in interlimb coordination reflected a strategy to prevent unexpected movements of the bag that could threaten body stability. Healthy older adults were able to predict the consequences of carrying a load and kept the MoS constant. They compensated for the disturbance caused by the transport of a relatively moderate load and performed the descending curb task successfully.
Background: Muscle fatigue is characterized by a decrease in muscle performance, accompanied by a... more Background: Muscle fatigue is characterized by a decrease in muscle performance, accompanied by an increase in perceived exertion to produce a desired amount of force. The duration of the fatigue effects is not completely clear regarding postural sway and force production in athletes. Research question: What is the effect of a specific fatigue protocol in postural sway and force production in female handball athletes and the recovery time necessary for these variables? Methods: Twenty female handball athletes participated in this study. Specific handball actions composed the fatigue protocol in the format of a circuit with the gradual increment of laps. They stood upright in one-leg posture on a force plate. For the maximum propulsion force (F MAX), they performed a countermovement jump on the force plate. The center of pressure (COP) and the F MAX were obtained at baseline, immediately after the exhaustion due to the fatigue protocol and every minute during the first 10 min of the recovery phase. Results: The F MAX decreased ∼9.5% after the fatigue protocol, whereas de COP area increased 224%. During the recovery phase, the F MAX and the COP area returned to baseline values after five minutes. Significance: The first five minutes immediately after the fatigue protocol represent the time interval where the fatigue effects are still present. Future studies willing to investigate the effects of fatigue in athletes should perform the analysis within this short time-window.
During locomotion, we respond to environmental and task changes by adjusting steps length and wid... 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...
The force variability of the plantar flexor muscles (PFM) appears to be directly related to the c... 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...
Our purpose was to verify the effects of the use of the anchors on postural control after the fat... 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.
Typically, falls in older adults occur when 2 tasks are performed simultaneously, due to the incr... 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.
There are different ways to add haptic input during walking which may affect walking balance. Thi... 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 ...
The Journal of sports medicine and physical fitness, Jan 16, 2016
The main aim of this study was to verify the relationship between the classification of coaches a... 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...
The purpose of the present study was to analyze the contribution of both exproprioceptive visual ... 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...
Background. Depending on the dimensions of a hole, the characteristics of the walking surface, an... 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...
Dynamic balance keeps the vertical projection of the center of mass within the base of support wh... 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...
Using conventional tDCS over the temporo-parietal junction (TPJ) we previously reported that it i... 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...
Research quarterly for exercise and sport, Jan 7, 2018
The purpose of this study was to compare the kicking performance of young soccer players in the U... 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...
Revista Brasileira de Geriatria e Gerontologia, 2016
Objective: The aim of the present study was to evaluate the influence of a balance training progr... 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...
Older adults have a greater incidence of falls, and risk of falls will increase when combining tw... 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...
Lilian Teresa Bucken Gobbi, or simply Lilian, a beloved friend of many of us, died unexpectedly o... more Lilian Teresa Bucken Gobbi, or simply Lilian, a beloved friend of many of us, died unexpectedly on October 20, 2022. We wrote this tribute to recognize her legacy in science. We reviewed Lilian's education and career and her contributions to the research on balance and locomotion in children, older adults and people with Parkinson's disease. We also acknowledged her pioneering work on physical activity interventions for people with Parkinson's disease. Finally, but not least important, we tried to show a little bit about the wonderful human being who Lilian was beyond her scientific contributions.
Objective: Converging evidence supporting an effect of transcranial direct current stimulation (t... 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...
BACKGROUND: Individuals with a perception of their fragile health can potentiate the fear of COVI... 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...
We investigated the effect of asymmetric load carrying using different bag types with the dominan... more We investigated the effect of asymmetric load carrying using different bag types with the dominant and non-dominant hands on upper limb coordination, walking adaptations, and stability control in a curbdescend task in older adults. Fourteen participants walked on a pathway with a 16-cm curb located in the middle. They walked without a load or asymmetrically carrying a load corresponding to 7% of their body mass. The weight was placed in two different bags (with and without strap) and carried by the dominant and non-dominant hands. The upper limb coordination analysis showed that the anti-phase pattern between right and left shoulder reduced considerably due to the almost motionless shoulder of the side carrying the load. The spatial-temporal walking parameters and curb negotiation variables were unaffected by load carriage. The margin of stability (MoS) was unchanged by load transportation in the AP direction. In the ML direction, taking the bag on the same side of the foot contacting the floor increased the MoS; however, when the load was incorporated into the COM model, the MoS did not differ anymore from the control condition. The changes in interlimb coordination reflected a strategy to prevent unexpected movements of the bag that could threaten body stability. Healthy older adults were able to predict the consequences of carrying a load and kept the MoS constant. They compensated for the disturbance caused by the transport of a relatively moderate load and performed the descending curb task successfully.
Background: Muscle fatigue is characterized by a decrease in muscle performance, accompanied by a... more Background: Muscle fatigue is characterized by a decrease in muscle performance, accompanied by an increase in perceived exertion to produce a desired amount of force. The duration of the fatigue effects is not completely clear regarding postural sway and force production in athletes. Research question: What is the effect of a specific fatigue protocol in postural sway and force production in female handball athletes and the recovery time necessary for these variables? Methods: Twenty female handball athletes participated in this study. Specific handball actions composed the fatigue protocol in the format of a circuit with the gradual increment of laps. They stood upright in one-leg posture on a force plate. For the maximum propulsion force (F MAX), they performed a countermovement jump on the force plate. The center of pressure (COP) and the F MAX were obtained at baseline, immediately after the exhaustion due to the fatigue protocol and every minute during the first 10 min of the recovery phase. Results: The F MAX decreased ∼9.5% after the fatigue protocol, whereas de COP area increased 224%. During the recovery phase, the F MAX and the COP area returned to baseline values after five minutes. Significance: The first five minutes immediately after the fatigue protocol represent the time interval where the fatigue effects are still present. Future studies willing to investigate the effects of fatigue in athletes should perform the analysis within this short time-window.
During locomotion, we respond to environmental and task changes by adjusting steps length and wid... 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...
The force variability of the plantar flexor muscles (PFM) appears to be directly related to the c... 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...
Our purpose was to verify the effects of the use of the anchors on postural control after the fat... 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.
Typically, falls in older adults occur when 2 tasks are performed simultaneously, due to the incr... 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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; 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.
There are different ways to add haptic input during walking which may affect walking balance. Thi... 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 ...
The Journal of sports medicine and physical fitness, Jan 16, 2016
The main aim of this study was to verify the relationship between the classification of coaches a... 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...
The purpose of the present study was to analyze the contribution of both exproprioceptive visual ... 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...
Background. Depending on the dimensions of a hole, the characteristics of the walking surface, an... 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...
Dynamic balance keeps the vertical projection of the center of mass within the base of support wh... 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...
Using conventional tDCS over the temporo-parietal junction (TPJ) we previously reported that it i... 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...
Research quarterly for exercise and sport, Jan 7, 2018
The purpose of this study was to compare the kicking performance of young soccer players in the U... 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...
Revista Brasileira de Geriatria e Gerontologia, 2016
Objective: The aim of the present study was to evaluate the influence of a balance training progr... 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...
Older adults have a greater incidence of falls, and risk of falls will increase when combining tw... 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...
Lilian Teresa Bucken Gobbi, or simply Lilian, a beloved friend of many of us, died unexpectedly o... more Lilian Teresa Bucken Gobbi, or simply Lilian, a beloved friend of many of us, died unexpectedly on October 20, 2022. We wrote this tribute to recognize her legacy in science. We reviewed Lilian's education and career and her contributions to the research on balance and locomotion in children, older adults and people with Parkinson's disease. We also acknowledged her pioneering work on physical activity interventions for people with Parkinson's disease. Finally, but not least important, we tried to show a little bit about the wonderful human being who Lilian was beyond her scientific contributions.
Objective: Converging evidence supporting an effect of transcranial direct current stimulation (t... 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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Papers by Renato Moraes