This study investigated whether postural configuration has a significant effect upon the kinematics of arm movements when humans performed unconstrained reach movements to visual targets. Eight subjects were required to reach to static visual targets (unperturbed REACH movements) or correct reach movements when the position of a target unexpectedly changed during the execution of a planned movement (perturbed reaches, or online corrections, OC). Subjects were required to execute REACH and OC movements in sitting and standing (STAND) positions. The height of the targets, distance from the right shoulder (acromion) and eccentricity in terms of the body midline were standardized between the two postural conditions before movements begun. Unperturbed REACH movements were executed to a central target placed at 130 % of outstretched arm length, along the midline (0°). Perturbed (OC) movements involved subjects initiating an arm movement to the 0° target upon its illumination. Two hundred milliseconds after the onset of the hand movement, the 0° target was extinguished and the target at 60° to the right of the midline (still at 130% outstretched arm distance) illuminated. Subjects had to correct their reach movements online to the new target. Results demonstrated that, despite evident differences in postural kinematics between the four experimental conditions (e.g. pelvis obliquity and trunk/pelvis rotation), postural configuration had little or no effect upon the endpoint kinematics of the finger. Most importantly, the STAND position, with its greater postural constraints, did not affect the time taken to initiate an OC, nor did it lengthen the time taken to complete the REACH or OC movements. Our results suggest, therefore, that postural constraints are accounted for by the central nervous system when executing complex arm reaching movements.

It has been suggested that the well-known health benefits associated with exercise can be explained by a placebo effect, and that greater effort should be given to convince people that their current behaviors have desirable health consequences. The overall purpose of this study was to test the efficacy of this "mind-set matters" hypothesis through the use of an expectancy-based intervention with adolescents. The study involved a four week randomized controlled trial with 348 Grade 9 adolescents (M (age) = 14.07 yrs, SD = 0.30), from four high schools, taking part in either a placebo-intervention condition (n = 188) or a control condition (n = 160). Participants in the placebo-intervention condition were informed that what they are already doing in school physical education lessons fulfills current recommendations for an active lifestyle. Participants in the control condition were not given this information. Four weeks after the intervention, adolescents in the placebo-intervention condition did not demonstrate significant changes in physiological health-related measures (diet, weight, body mass index, percentage body fat, heart rate, mean arterial pressure). The findings question the external validity of the "mind-set matters" hypothesis with adolescents, and suggest that simply encouraging adolescents to believe that they are healthy may not enable them to respond with improved indicators of physical health.