Postural control development from late childhood through young adulthood.

Background: The development of stable postural control is characterized by changes in sway variability and periods of rapid reorganization of motor system components.

Research Question: The current study examined whether changing biomechanical and perceptual demands influences the postural control behavior during development.

Method: The center of pressure (COP) was assessed via a cross-sectional design.

Perception of another person's maximum reach-with-jump height from walking kinematics.

Humans can perceive affordances (possibilities for action) for themselves and others, including the maximum overhead height reachable by jumping (reach-with-jump height, RWJ). While observers can accurately perceive maximum RWJ for another person without previously seeing the person jump, estimates improve after viewing the person walk, suggesting there is structure in walking kinematics that is informative about the ability to produce vertical force for jumping. We used principal component analysis (PCA) to identify patterns in human walking kinematics that specify another person's maximum RWJ ability, and to determine whether athletes are more sensitive than non-athletes to these patterns.

Ontogeny of tool use: how do toddlers use hammers?

Hammering with a hand tool appears early in life. Skillful hammering involves accommodating movements to properties of the hammer, orienting the hammer's head to the item to be struck, and maintaining stable posture during forceful action with the arm(s). We aimed to characterize development of these abilities in young children (12, 18, and 24 months old).

Functional Task Constraints Foster Enhanced Postural Control in Children With Cerebral Palsy.

Background: Postural instability is a classical characteristic of cerebral palsy (CP), but it has not been examined during functional play activity. Recent work has demonstrated that when motor tasks are made functionally more relevant, performance improves, even in children with movement pathology. It is possible that in a disease state, the underlying control mechanisms that are associated with healthy physiology must be elicited.

Children with cerebral palsy effectively modulate postural control to perform a supra-postural task.

The purpose of this study was to determine whether signatures of adaptive postural control remain present in children with cerebral palsy (CP) when they performed a supra-postural task (i.e., a task performed above and beyond the control of posture) requiring them to balance a marble inside a tube held in the hands.

Lower-limb proprioceptive awareness in professional ballet dancers.

Enhanced proprioceptive feedback strengthens synergistic muscle groups and stabilizes the coordination of limbs, thus contributing to the movement efficiency of ballet dancers. The present study compared lower-limb proprioceptive awareness in professional ballet dancers to matched controls who had no dance training. Two assessment methods were used to test the hypothesis that ballet dancers would demonstrate increased proprioceptive awareness in the ankle, knee, and hip: 1.

Multi-segmental postural coordination in professional ballet dancers.

Ballet dancers have heightened balance skills, but previous studies that compared dancers to non-dancers have not quantified patterns of multi-joint postural coordination. This study utilized a visual tracking task that required professional ballet dancers and untrained control participants to sway with the fore-aft motion of a target while standing on one leg, at target frequencies of 0.2 and 0.

Perceiving affordances for joint actions.

Two individuals acting together to achieve a shared goal often have an emergent set of afforded behavioral possibilities that may not easily reduce to either acting alone. In a series of experiments we examined the critical boundaries for transitions in behavior for individuals walking through an aperture alone or alongside another actor as a dyad. Results from experiment 1 indicated that an intrinsically scaled critical boundary for behavioral transitions was different in individuals than in dyads performing a similar task.

The production of bimanual percussion in 12- to 24-month-old children.

Bimanual coordination represents a complex self-organizing system that is subject to both internal and contextual constraints. Although there has been interest in examining bimanual development throughout the lifespan, few data exist relative to the bimanual activity of children between 1 and 4 years of age. The study reported here represents an initial effort to address this gap.

Relational spatial reasoning by a nonhuman: the example of capuchin monkeys.

The authors review spontaneous manipulation and spatial problem solving by capuchin monkeys to illuminate the nature of relational reasoning (wherein two or more elements of a problem or situation are considered together to arrive at a course of action) that these monkeys use in goal-directed activity. Capuchin monkeys master problems with one, two, or three spatial relations, and if more than one relation, at least two relations may be managed concurrently. They can master static and dynamic relations and, with sufficient practice, can produce specific spatial relations through both direct and distal action.

Choosing and using tools: capuchins (Cebus apella) use a different metric than tamarins (Saguinus oedipus).

Cotton-top tamarins (Saguinus oedipus) selected canes positioned so that a straight inward pull brought food within reach (M. D. Hauser, 1997; see also record 1997-41347-003).