An Analysis of a Discrete Complex Skill Using Bernstein's Stages of Learning

Smith, Darla R.; McCabe, D. Rozena; Wilkerson, Jerry D.

doi:10.2466/pms.2001.93.1.181

Cited by 7 publications

(9 citation statements)

References 9 publications

(7 reference statements)

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“…13,[16][17][18][19] Progress of skill acquisition involves the release of DF. 12,15 This was shown in the AMC group as their elbows became more involved in the task of two-handed catching (Table I; Fig. 1).…”

Section: Discussionmentioning

confidence: 76%

“…Thus, across trials, children with DCD kept the individual DF of the elbow 'rigidly, spastically fixed' to solve the control problem. 12,13,15,19 Bernstein 12 also proposed that introducing temporary, rigid couplings between independent DF may reduce the computation burden on the central nervous system, because only the synergy needs active control. The data of the present study suggest that children with DCD and their AMCs also couple their limbs during a more dynamic task of catching a ball twohandedly.…”

Section: Discussionmentioning

confidence: 99%

“…With practice, both the range of motion at the elbows and the variability of angular excursion of the elbows increased, suggesting that DF were actually released and incorporated in the movement coordination. 13,15 This allowed the AMC participants to produce various solutions to the motor problem, and the large repertoire of solutions available to them was enhanced with practice. 7 In contrast to the AMC group, the children with DCD did not show such an increase in the variability of angular excursion of the elbows (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…12 Kinematic analysis has shown that during initial learning of a ski simulator, task performers 'froze' their DF; 13 in addition, learners of a racquetball forehand exhibited smaller ranges of motion for the upper limbs, pelvis, and torso during initial performance. 14,15 A second solution to reducing the DF is to instigate rigid and strong couplings between independent DF (such as the joints). In other words, the angular excursions of two or more joints are linked and thus control is reduced to a single DF as the limbs perform in synchrony.…”

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confidence: 99%

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Ball catching in children with developmental coordination disorder: control of degrees of freedom

Utley

Steenbergen

Astill

2006

Develop Med Child Neuro

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This study investigated two-handed catching in eight children (four males, four females) aged 7 to 8 years (mean 7y 4mo [SD 3mo]) with developmental coordination disorder (DCD) and their age-matched controls (AMCs). Kinematic data were collected to examine Bernstein's (1967) notion of freezing and releasing degrees of freedom (DF). Participants were asked to catch a ball 30 times, delivered in three blocks of 10 trials. Video analysis showed that children with DCD caught significantly fewer balls than their AMCs (p≤0.001) counterparts. Kinematic analyses showed that children with DCD exhibited smaller ranges of motion and less variable angular excursions of the elbow joints than their AMCs, and that their elbows are more rigidly coupled (p≤0.001). These data suggest that children with DCD rigidly fix and couple their limbs to reduce the number of DF actively involved in the task.Developmental coordination disorder (DCD) describes children with a marked impairment in the development of motor coordination that significantly interferes with daily activities and, often, academic achievement. These coordination difficulties are not due to a general medical condition, be it physical or mental. 1 Published work shows that children with DCD are a heterogeneous group with a variety of patterns of strengths and weaknesses yet rarely highly skilled at any motor task. 2,3 Children with DCD have been shown by many to exhibit difficulties with ball-handling skills. [2][3][4][5][6][7] Studies that have investigated ball catching in children with DCD suggest their problems could be due to a disturbance of visual perception 8 or problems with visuospatial anticipation and information processing. 9 Research has shown that children with DCD require more time than children without DCD to determine which cues are useful for their decision-making process in catching. 5 These observations are consistent with the notion that children with DCD have difficulty selecting appropriate motor responses, 10 suggesting that this could contribute to the difficulties observed when catching balls.Published work has also shown that children with DCD have problems with both temporal and spatial aspects of catching a ball. They exhibit more grasping errors and showed less elbow flexion and arm extension than their peers, and less bending of the elbows to absorb the force of the ball. 6 These observations suggest that children with DCD place restrictions upon their movement system to restrict the number of joints or degrees of freedom (DF) involved when catching a ball. 6 Catching a ball with two hands requires the coordination of many DF. Simply put, a DF refers to how many axes a joint can move about. For example, the elbow only has one DF: the forearm can flex toward or extend away from the upper arm. 11 If we take into account the number of joints and/or muscles working in the arms, there are far more DF available than the minimum number required to successfully accomplish the task. 12 These redundant DF give flexibility to the motor apparatus tha...

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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Ball catching in children with developmental coordination disorder: control of degrees of freedom

Utley

Steenbergen

Astill

2006

Develop Med Child Neuro

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“…Although some evidence supporting this hypothesis is provided by a number of kinematic studies of learning tasks (McDonald et al 1989;Smith et al 2001;Vereijken et al 1992), contradictory results have been reported (Caillou et al 2002;Ko et al 2003). Moreover, experimentally, the proposed "elimination of DOFs" has typically meant a reduction in the range of joint motion (Vereijken et al 1992), in which case no DOFs are actually eliminated.…”

Section: Introductionmentioning

confidence: 99%

The role of kinematic redundancy in adaptation of reaching

2006

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Although important differences exist between learning a new motor skill and adapting a well-learned skill to new environmental constraints, studies of force field adaptation have been used frequently in recent years to identify processes underlying learning. Most of these studies have been of reaching tasks that were each hand position was specified by a unique combination of joint angles. At the same time, evidence has been provided from a variety of tasks that the central nervous system takes advantage of the redundancy available to it when planning and executing functional movements. The current study attempted to determine whether a change in the use of joint motion redundancy is associated with the adaptation process. Both experimental and control subjects performed 160 trials of reaching in each of four adaptation phases, while holding the handle of a robot manipulandum. During the first and last adaptation phases, the robot motors were turned off. During phases 2 and 3 the motors produced a velocity-dependent force field to which experimental subjects had to adapt to regain relatively straight line hand movements during reaching to a target, while the motors remained off for the control group. The uncontrolled manifold (UCM) method was used to partition the variance of planar clavicle-scapular, shoulder, elbow and wrist joint movements into two orthogonal components, one (V UCM ) that reflected combinations of joint angles that were equivalent with respect to achieving the average hand path and another (V ORT ) that took the hand away from its average path. There was no change in either variance component for the control group performing 640 nonperturbed reaches across four 'pseudo-adaptation' phases. The experimental group showed adaptation to reaching in the force field that was accompanied initially by an increase in both components of variance, followed by a smaller decrease of V UCM than V ORT during 320 practice reaches in the force field. After initial re-adaptation to reaching to the null field, V UCM was higher in experimental than in control subjects after performing a comparable number of reaches. V UCM was also larger in the experimental group after re-adaptation when compared to the 160 null field reaching trials performed prior to initial force field introduction. The results suggest that the central nervous system makes use of kinematic redundancy, or flexibility of motor patterns, to adapt reaching performance to unusual force fields, a fact that has implications for the hypothesis that motor adaptation requires learning of formal models of limb and environmental dynamics.

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