scholarly journals Anticipatory Postural Adjustments in Dart Throwing

2013 ◽  
Vol 37 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Grzegorz Juras ◽  
Kajetan Słomka
Keyword(s):  
Repeated Measures ◽  
Training Session ◽  
Motor Task ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Target Size ◽  
Postural Adjustments ◽  
Dart Throwing ◽  
Task Parameters ◽  
Kinetics Of

The aim of this study was to explore the effects of accuracy constraints on the characteristics of anticipatory postural adjustments (APA) in a task that involves a movement consisting of a controlled phase and a ballistic phase. It was hypothesized that APA scaling with task parameters (target size) would be preserved even when the task is performed by muscles that have no direct effects on APA. Sixteen healthy right handed subjects participated in the study. All participants had no prior experience in dart throwing. Subjects’ average age was 24.1 ± 1.9 years. A force platform and a motion capture system were used to register kinetics of the body and kinematics of the throwing arm and throwing accuracy. The experiment consisted of six series of twenty consecutive dart throws to a specified target. Target sizes (T2-T6) were set at 25%, 50%, 75%, 125% and 150% of target 1 (T1) initially set as the spread of the last 20 throws in a 50 throw training session. This allowed to distinguish six indexes of difficulty (ID’s) ranging from 2,9 to 5,9. A one-way ANOVA for repeated measures was used for statistical analysis. Results of ANOVA showed a significant effect of target size at Constant Error but no effect at APA time. There were also no significant differences between hit and miss throws. From a control perspective, it can be stated that changes in central commands did not lead to changes in APA time in the analyzed motor task.

Modification of postural responses and step initiation: evidence for goal-directed postural interactions

1994 ◽  
Vol 72 (6) ◽  
pp. 2892-2902 ◽  
Author(s):  
A. L. Burleigh ◽  
F. B. Horak ◽  
F. Malouin
Keyword(s):  
External Perturbation ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Original Position ◽  
Foot Pressure ◽  
Postural Adjustments ◽  
Step Initiation ◽  
Postural Responses ◽  
Surface Translation ◽  
Automatic Postural Responses

1. In this study, the interaction between anticipatory postural adjustments for step initiation and automatic postural responses to an external perturbation were investigated by having subjects initiate a voluntary forward step while perturbed by a backward surface translation, which caused forward sway of the body. The postural adjustments for step initiation act to move the body center of mass (COM) forward, whereas the automatic postural responses act to move the COM backward to restore stance equilibrium. Because the postural behaviors are in opposition, we asked whether a temporal hierarchy exists in which automatic postural responses are executed to restore equilibrium and followed by stereotypic postural adjustments for step initiation, or whether the interaction between these two postural behaviors is more dynamic. 2. Lower extremity electromyographs (EMGs), ground reaction forces, and kinematics were recorded from 10 subjects during three conditions: to quantify the anticipatory postural adjustments for step initiation, subjects stepped forward as soon as they felt a proprioceptive cue; to quantify the automatic postural responses to perturbation, subjects maintained stance equilibrium in response to a backward surface translation under both feet; and to quantify the interaction between the postural adjustments for the voluntary step and the automatic responses to the perturbation, subjects were exposed to a backward surface translation and instructed to step forward as soon as they felt the platform begin to move. 3. The anticipatory adjustments for step initiation included tibialis activation [stance limb = 163 +/- 28 (SE) ms; swing limb = 173 +/- 33 ms] and soleus inhibition resulting in center of foot pressure (COP) moving backward and lateral toward the swing limb to propel the COM forward over the stance limb. Subsequently, activation of the swing limb gastrocnemius resulted in heel-off. In contrast, the automatic postural adjustments for maintenance of stance equilibrium during a backward surface translation included activation of soleus and gastrocnemius (104 +/- 23 ms and 115 +/- 14 ms, respectively) resulting in a symmetrical forward displacement of the COP that moved the COM back to its original position with respect to the feet. 4. When a forward step was initiated in response to the translation, the automatic postural responses were reduced in amplitude bilaterally in soleus and in the stance limb gastrocnemius. When present the postural response occurred at the same latency when the goal was to initiate a step as when the goal was to maintain standing.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Anticipatory Postural Adjustments and kinematic arm features when postural stability is manipulated

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4309 ◽  
Author(s):  
Bianca Callegari ◽  
Ghislain Saunier ◽  
Manuela Brito Duarte ◽  
Gizele Cristina da Silva Almeida ◽  
Cesar Ferreira Amorim ◽  
...  
Keyword(s):  
Upper Limb ◽  
Postural Stability ◽  
Motor Planning ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Postural Adjustments ◽  
Pointing Task ◽  
Standing Up ◽  
Degree Of Stability

Beyond the classical paradigm that presents the Anticipatory Postural Adjustments (APAs) as a manner to create forces that counteract disturbances arising from the moving segment during a pointing task, there is a controversial discussion about the role APAs to facilitate the movement and perform a task accurately. In addition, arm kinematics features are classically used to infer the content of motor planning for the execution and the control of arm movements. The present study aimed to disentangle the conflicting role of APAs during an arm-pointing task in which the subjects reach a central diode that suddenly turns on, while their postural stability was manipulated. Three postures were applied: Standing (Up), Sit without feet support (SitUnsup) and Sit with feet support (SitSup). We found that challenging postural stability induced an increase of the reaction time and movement duration (observed for the SitUnsup compared to SitSUp and Up) as well as modified the upper-limb velocity profile. Indeed, a greater max velocity and a shorter deceleration time were observed under the highest stability (SitSup). Thus, these Kinematics features reflect less challenging task and simple motor plan when the body is stabilized. Concerning the APAs, we observed the presence of them independently of the postural stability. Such a result strongly suggests that APAs act to facilitate the limb movement and to counteract perturbation forces. In conclusion, the degree of stability seems particularly tuned to the motor planning of the upper-limb during a pointing task whereas the postural chain (sitting vs. standing) was also determinant for APAs.

scholarly journals A Novel Viewpoint on the Anticipatory Postural Adjustments During Gait Initiation

2021 ◽  
Vol 15 ◽  
Author(s):  
Veronica Farinelli ◽  
Francesco Bolzoni ◽  
Silvia Maria Marchese ◽  
Roberto Esposti ◽  
Paolo Cavallari
Keyword(s):  
Center Of Pressure ◽  
Force Plate ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Gait Initiation ◽  
Concentrated Force ◽  
Postural Adjustments ◽  
Leg Muscles

Anticipatory postural adjustments (APAs) are the coordinated muscular activities that precede the voluntary movements to counteract the associated postural perturbations. Many studies about gait initiation call APAs those activities that precede the heel-off of the leading foot, thus taking heel-off as the onset of voluntary movement. In particular, leg muscles drive the center of pressure (CoP) both laterally, to shift the body weight over the trailing foot and backward, to create a disequilibrium torque pushing forward the center of mass (CoM). However, since subjects want to propel their body rather than lift their foot, the onset of gait should be the CoM displacement, which starts with the backward CoP shift. If so, the leg muscles driving such a shift are the prime movers. Moreover, since the disequilibrium torque is mechanically equivalent to a forward force acting at the pelvis level, APAs should be required to link the body segments to the pelvis: distributing such concentrated force throughout the body would make all segments move homogeneously. In the aim of testing this hypothesis, we analyzed gait initiation in 15 right-footed healthy subjects, searching for activities in trunk muscles that precede the onset of the backward CoP shift. Subjects stood on a force plate for about 10 s and then started walking at their natural speed. A minimum of 10 trials were collected. A force plate measured the CoP position while wireless probes recorded the electromyographic activities. Recordings ascertained that at gait onset APAs develop in trunk muscles. On the right side, Rectus Abdominis and Obliquus Abdominis were activated in 11 and 13 subjects, respectively, starting on average 33 and 54 ms before the CoP shift; Erector Spinae (ES) at L2 and T3 levels was instead inhibited (9 and 7 subjects, 104 and 120 ms). On the contralateral side, the same muscles showed excitatory APAs (abdominals in 11 and 12 subjects, 27 and 82 ms; ES in 10 and 7 subjects, 75 and 32 ms). The results of this study provide a novel framework for distinguishing postural from voluntary actions, which may be relevant for the diagnosis and rehabilitation of gait disorders.

scholarly journals Effects of self-controlled knowledge of performance on motor learning and self-efficacy: A kinematic study

2021 ◽  
Vol 13 (1) ◽  
pp. 187-196
Author(s):  
Rezvaneh Makki ◽  
Maryam Abdoshahi ◽  
Saeed Ghorbani
Keyword(s):  
Motor Learning ◽  
Self Efficacy ◽  
Repeated Measures ◽  
Statistical Tests ◽  
Motor Task ◽  
Movement Pattern ◽  
Self Control ◽  
Acquisition Phase ◽  
Dart Throwing ◽  
Coordination Patterns

Abstract Study aim: To evaluate the effects of providing the learners with self-controlled knowledge of performance (KP) on motor learning and self-efficacy (SE) in a dart-throwing motor task. Material and methods: The participants were thirty female university students who were divided into two groups including self-control and yoked groups. Participants performed five blocks of five trials in the acquisition phase, and retention and transfer tests of 10 trials one day later. Intra-limb coordination patterns (movement pattern), throwing scores, and SE (both movement pattern and movement outcome) were measured as dependent variables. Independent t test and one-way ANOVA with repeated measures were used as statistical tests. Results: The self-controlled group performed significantly better than yoked group on movement pattern during the acquisition phase (F1,28 = 24.239, p = 0.001) and the retention test (t28 = –3.074, p = 0.007). However, there were no significant differences between groups in terms of throwing scores and SE during the acquisition, retention, and transfer phases (all p > 0.05). Conclusion: Providing self-controlled KP can improve learning of movement pattern in the novices but do not necessary increase movement outcome or SE.

scholarly journals Characterization of Anticipatory Postural Adjustments in Lateral Stepping: Impact of Footwear and Lower Limb Preference

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8244
Author(s):  
Yuri Russo ◽  
Dragan Marinkovic ◽  
Borislav Obradovic ◽  
Giuseppe Vannozzi
Keyword(s):  
Everyday Life ◽  
Lower Limb ◽  
Force Plate ◽  
Motor Task ◽  
Anticipatory Postural Adjustments ◽  
Postural Adjustments ◽  
Spatiotemporal Parameters ◽  
Base Of Support ◽  
Force Plate Data

Lateral stepping is a motor task that is widely used in everyday life to modify the base of support, change direction, and avoid obstacles. Anticipatory Postural Adjustments (APAs) are often analyzed to describe postural preparation prior to forward stepping, however, little is known about lateral stepping. The aim of the study is to characterize APAs preceding lateral steps and to investigate how these are affected by footwear and lower limb preference. Twenty-two healthy young participants performed a lateral step using both their preferred and non-preferred leg in both barefoot and shod conditions. APA spatiotemporal parameters (size, duration, and speed) along both the anteroposterior and mediolateral axes were obtained through force plate data. APAs preceding lateral stepping showed typical patterns both along the anteroposterior and mediolateral axis. RM-ANOVA highlighted a significant effect of footwear only on medio-lateral APAs amplitude (p = 0.008) and velocity (p = 0.037). No differences were found for the limb preference. APAs in lateral stepping presented consistent features in the sagittal component, regardless of limb/shoe factors. Interestingly, the study observed that footwear induced an increase in the medio-lateral APAs size and velocity, highlighting the importance of including this factor when studying lateral stepping.

scholarly journals Transfer of Dynamic Learning Across Postures

2009 ◽  
Vol 102 (5) ◽  
pp. 2816-2824 ◽  
Author(s):  
Alaa A. Ahmed ◽  
Daniel M. Wolpert
Keyword(s):  
Motor Task ◽  
Standing Position ◽  
The Body ◽  
Whole Body ◽  
Robot Dynamics ◽  
The Novel ◽  
Dynamic Learning ◽  
Postural Adjustments ◽  
Body Segments ◽  
Combined Movements

When learning a difficult motor task, we often decompose the task so that the control of individual body segments is practiced in isolation. But on re-composition, the combined movements can result in novel and possibly complex internal forces between the body segments that were not experienced (or did not need to be compensated for) during isolated practice. Here we investigate whether dynamics learned in isolation by one part of the body can be used by other parts of the body to immediately predict and compensate for novel forces between body segments. Subjects reached to targets while holding the handle of a robotic, force-generating manipulandum. One group of subjects was initially exposed to the novel robot dynamics while seated and was then tested in a standing position. A second group was tested in the reverse order: standing then sitting. Both groups adapted their arm dynamics to the novel environment, and this movement learning transferred between seated and standing postures and vice versa. Both groups also generated anticipatory postural adjustments when standing and exposed to the force field for several trials. In the group that had learned the dynamics while seated, the appropriate postural adjustments were observed on the very first reach on standing. These results suggest that the CNS can immediately anticipate the effect of learned movement dynamics on a novel whole-body posture. The results support the existence of separate mappings for posture and movement, which encode similar dynamics but can be adapted independently.

scholarly journals Anticipatory Postural Adjustments in the Frail Older Adults When Postural Stability is Manipulated

2020 ◽  
Author(s):  
Bianca Callegari ◽  
Alexandre Kubicki ◽  
Ghislain Saunier ◽  
Manuela Brito Duarte ◽  
Gizele Cristina da Silva Almeida ◽  
...  
Keyword(s):  
Older Adults ◽  
Postural Stability ◽  
Motor Planning ◽  
Functional Independence ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Upright Posture ◽  
Postural Adjustments ◽  
Frail Older Adults ◽  
The Impact

Abstract Background: Anticipatory Postural Adjustments (APAs) are importantly affected by age and may represent restrictions for functional independence. Previous studies have already highlighted some delayed APAs during self-generated rapid arm movements in aged adults, as well as in cases of non-optimal aging, such as in frail older adults. In young (Y) adults, it was also previously demonstrated that changing the postural stability (i.e. seated vs. upright posture) affects the motor planning and APAs. Considering the clinical relevance of these balance tasks in the functional independence in frail older adults (FOA), and the lack of literature about this task, the present study aimed to investigate the impact of these different conditions of postural stability on APAs in FOA. Methods: In this paper, participants executed an arm-pointing task to reach a diode immediately after it turned on, under different conditions of stability (seated with and without feet support and in upright posture). Results: The main finding of this study is that the adopted posture and body stabilization in FOA did not reflect differences in APAs or kinematic features. In addition, they did not present an optimal APA, since postural muscles are recruited simultaneously with the deltoid. Conclusion: Thus, FOA seem to use a single non-optimal motor plan to assist the task performance and counterbalance perturbation forces, in which they present similar APAs and do not modify their kinematics features according to the body stabilization (i.e. less challenging task present greater finger velocity).

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