William P. Berg

Effect of cellular telephone conversations and other potential interference on reaction time in a braking response

This experiment studied the effect of phone conversations and other potential interference on reaction time (RT) in a braking response. Using a laboratory station which simulated the foot activity in driving, 22 research participants were requested to release the accelerator pedal and depress the brake pedal as quickly as possible following the activation of a red brake lamp. Mean reaction time was determined for five conditions: (a) control, (b) listening to a radio, (c) conversing with a passenger, (d) conversing using a hand-held phone, and (e) conversing using a hands-free phone. Results indicated that conversation, whether conducted in-person or via a cellular phone caused RT to slow, whereas listening to music on the radio did not.

EFFECT OF THE INTENSITY OF WIRELESS TELEPHONE CONVERSATIONS ON REACTION TIME IN A BRAKING RESPONSE

Recently, concern has grown about the extent to which wireless telephone use by motor vehicle drivers constitutes a threat to traffic safety. This experiment investigated the effect of the intensity of wireless telephone conversations on reaction time (RT) for a braking response. Using a laboratory station to mimic the foot activity in driving, 16 adults were instructed to release the accelerator pedal and depress the brake pedal as quickly as possible following the activation of a red brake light. Mean RT was measured for 5 conditions which manipulated the intensity of a conversation, i.e., demand for attention, conducted on a wireless telephone. Analysis indicated that wireless telephone use caused a decrement in RT, however, there was no significant effect associated with intensity of the conversation across intensity.

Effect of walking speed on typing performance using an active workstation.

This study tested the effect of treadmill walking speed on typing performance when these tasks were performed simultaneously. 24 research participants (M age = 23.2 yr.) performed a typing test under each of four conditions including the control (seated), treadmill walking at 1.3 km/hr., 2.25 km/hr., and 3.2 km/hr. Results indicated that treadmill walking had a detrimental effect on typing performance, but that the walking speed of 2.25 km/hr. would result in better typing performance than the slower and faster speeds. Seated typing was better than typing while walking at 1.3 km/hr. and typing while walking at 3.2 km/hr. Typing performance while walking at 2.25 km/hr. was not different than seated typing performance. The results support the potential of treadmill walking at 2.25 km/hr. to provide low-intensity physical activity without compromising typing performance.

Stepping performance during obstacle clearance in women: age differences and the association with lower extremity strength in older women.

OBJECTIVE: To compare stepping performance during obstacle clearance in younger and older women, and to examine the relationship between lower extremity strength and stepping performance during obstacle clearance in older women.

Correlates of Recurrent Falling in Independent Community-Dwelling Older Adults

This study compared the ability of selected measures of vision, health, physical activity and performance, and fall history to predict the risk of recurrent falls in independent community-dwelling older adults. Of particular interest was the association between visual field (VF) constriction and falling. Age-related VF constriction is well documented and is known to accelerate in persons over age 55. Although several authors have implied that VF constriction in older adults could contribute to instability and falls, there has been no attempt to systematically examine this relationship. A battery of tests were administered to men and women (N = 96) 60-88 years of age. Falls were closely monitored for 1 year following the testing. Fifty of the 96 participants (52%) fell during the 1-year monitoring period, amassing a total of 91 falls, 5 of which resulted in fractures. There were 46 nonfallers, 27 one-time fallers, and 23 recurrent fallers. A stepwise logistic regression analysis revealed that average VF constriction, use of eyeglasses, and low systolic blood pressure were independently associated with recurrent falling. On discriminant function analysis, these 3 variables predicted status as a recurrent faller correctly in 48% of cases, and predicted nonfaller status correctly in 93% of cases. The overall performance of the model was 70%. Hypotheses are offered for how average VF constriction, use of eyeglasses, and low systolic blood pressure could influence stability and fall risk in older adults.

SIZE OF THE VISUAL FIELD IN COLLEGIATE FAST-PITCH SOFTBALL PLAYERS AND NONATHLETES

The purpose of this study was to examine whether visual-field size differed between female Division I collegiate fast-pitch Softball players and female college students who were nonathletes. The relationship between visual-field size and batting performance among the softball players was also examined. 24 female undergraduate students (12 varsity fast-pitch softball players and 12 nonathletes) participated. The size of the visual field was measured via manual kinetic perimetry, and batting performance was assessed using a batting-skill test as well as batting averages for an entire competitive season. Analyses indicated that the mean visual-field size of softball players was significantly larger than that of nonathletes. However, there was no relationship between visual-field size and batting performance among the softball players. Results are discussed with respect to the origin of the superiority of visual-field size of softball players.

Differential mastication kinematics of the rabbit in response to food and water: implications for conditioned movement.

Analysis of naturalistic chewing patterns may provide insight into mapping the neural substrates of jaw movement control systems, including their adaptive modification during the classically conditioned jaw movement (CJM) paradigm. Here, New Zealand White rabbits were administered food and water stimuli orally to evaluate the influence of stimulus consistency on masticatory pattern. Chewing patterns were recorded via video camera and movements were analyzed by computerized image analysis. The mandibular kinematics, specifically the extent of dorsal/ventral, medial/lateral, and rostral/caudal movement, were significantly larger in food-evoked than water-evoked chewing. Water-evoked chewing frequency, however, was significantly higher than that of food-evoked movements. In light of known cortical mastication modulatory centers, our findings implicate different neural substrates for the responses to food and water stimuli in the rabbit. A detailed delineation of jaw movement patterns and circuitry is essential to characterize the neural substrates of CJM.

Evidence of unconscious motor adaptation to cognitive and auditory distraction

Using a simulated driving station, 36 participants applied the brake as quickly as possible following the activation of a red light under each of six conditions including (1) the control (braking only), (2) 72 dBA music stimulus, (3) 86 dBA music stimulus, (4) cell phone conversation, (5) cell phone conversation and 72dBA music, and (6) cell phone conversation and 86dBA music. Participants were distracted by the cell phone conversation, as demonstrated by slower response time and reaction time (RT). The addition of the music stimulus, even at 86 dBA, did not exacerbate the deficits. Braking movement time was faster, and peak braking force greater when the cell phone conversation was present than when it was absent. Participants appear to have anticipated impaired RT and adapted unconsciously by executing a more rapid movement to the brake pedal. Also, participants appear to have compensated for slower RT by applying greater braking force. The adaptive behavior observed in the experiment is discussed in the context of unconscious goal pursuit and neuromotor noise theory.

The impact of object weight, reach distance, discomfort and muscle activation on the location of preferred critical boundary during a seated reaching task

Successful performance of a goal-directed action requires the prospective actor to perceive the environment relative to their action capabilities and tailor their movements accordingly. The current study examined the roles of reach distance, object (power drill) weight, gender, discomfort, and muscle activation (anterior deltoid, upper trapezius, biceps, ventral and dorsal forearm) in determining the location of the transition between an arm-only and an arm-and-torso reach (preferred critical boundary) during a seated reach task in which participants had to direct a power drill toward a target. Generalized Estimating Equations (GEE) used extrinsic (independent of the participant) and intrinsic measures (relative to the biodynamic properties of the participant) of reach distance and drill weight, discomfort judgments, and EMG integral recordings for the five muscles to identify factors that best predicted the type of reach used. GEE revealed that intrinsic measures of reach distance and drill weight were superior predictors compared to extrinsic measures. Discomfort judgment and upper trapezius activity were also significant predictors of the location of the preferred critical boundary.

How to study movement in children

Publisher Summary The chapter is divided into six sections: First, a brief review of the past 25 years of motor development research, focusing primarily on the style of inquiry and the nature of the dependent variables used. Second, a discussion of the dependent variables that traditionally measures the product rather than the process of movement, and the ways in which their contribution to the description and analysis of movement patterns in children has both helped and constrained progress. Third, the movement studies of children incorporating the ecological perspective. Fourth, research on fetal motor activity is reviewed in the chapter. Fifth, a discussion of periodicity in motor behavior; the ways in which it is measured and its promise in understanding movement behavior is illustrated in the chapter. A sixth and final section summarizes the chapter and comments on future directions and initiatives, one of which is the use of allometry as a technique for studying movement patterns in children.