Locomotor Coordination, Visual Perception and Head Stability during Running

Perception and action are coupled such that information from the perceptual system is related to the dynamics of action in order to regulate behavior adaptively. Using running as a model of a cyclic behavior, this coupling involves a continuous, cyclic relationship between the runner’s perception of the environment and the necessary adjustments of the body that ultimately result in a stable pattern of behavior. The purpose of this paper is to illustrate how individuals relate visual perception to rhythmic locomotor coordination patterns in conditions during which foot–ground collisions and visual task demands are altered. We review the findings of studies conducted to illustrate how humans change their behavior to maintain head stability during running with and without various degrees of visual challenge from the environment. Finally, we show that the human body adapts specific segment/joint configuration and coordination patterns to maintain head stability, both in the lower extremity and upper body segments, together with an increase in coordinative variability. These results indicate that in human locomotion, under higher speed (running) and visual task demands, systematic adaptations occur in the rhythmic coupling between the perceptual and movement systems

EYE MOVEMENTS AND LIMB KINEMATICS IN MOVING TARGET AIMING

INTRODUCTION: Previous eye movement studies in far target aiming have shown that a longer final eye fixation right before movement initiation results in enhanced performance accuracy (e.g., Vickers, 1996). Previous studies have been limited to fixed target aiming. In the present study eye movements were measured while participants attempted to intercept a moving target. The identification of the relationship between eye movements and limb kinematics in moving target interception will provide further understanding of perceptionaction coupling in rapid intercepting movement

Effects of a Four-Week Core Stability Exercise on Functional Movement and Balance in People with Mild Lower-limb Discomfort

This study aimed to investigate the effects of a short-term core stability exercise on functional movement and balance in people with mild lower-limb discomfort. Twenty people with mild lower-limb discomfort were randomly assigned to control (CG) and core stability exercise training groups (SG, n=10 each). The SG completed twenty 30-min training sessions consisting of Pilates exercises for four weeks. Functional movement, balance, and discomfort level were assessed before and after core stability exercise, using a functional movement test, balance test and visual analogue scale (VAS), respectively. A mixed ANOVA with repeated measures was performed to determine the differences. SG demonstrated a significant increase in hurdle step (p = 0.024, group × time effect) and shoulder mobility (p = 0.037, group × time effect). The dynamic balance scores were significantly increased from the baseline in both limbs (right, p = 0.007; left, p = 0.011, time effect). Post-hoc pairwise comparisons indicated these increases were significant only in SG. Additionally, ankle pain was significantly reduced in SG (p = 0.023, group × time effect). This study highlights that four weeks of core stability exercise can positively affect the lower limbs’ functional movement and balance in people with mild lower-limb discomfort

Pilot study of impact of a pedal desk on postprandial responses in sedentary workers

Physical inactivity has been linked to rates of obesity, diabetes, and heart disease through insulin resistance and other mechanisms. Although sedentary workplace environments have unintentionally contributed to the risk for chronic diseases, innovations in the workplace environment could potentially rectify this public and occupational health problem. Purpose: To evaluate the effects of light-intensity physical activity using a pedal desk (PD) compared with a standard desk (STD) in a pilot study on postprandial metabolic responses and work skills. Methods: Twelve overweight/obese full-time sedentary office workers (six men and six women; body mass index, 28.7 +/- 3.6 kg m-2) were tested in two conditions: 1) PD, pedaling at self-selected light-intensity pace for 2 h and 2) STD, remaining seated for 2 h in a conventional workstation setup while performing scripted computer-based work tasks. Blood samples were analyzed for plasma glucose, insulin, and free-fatty acids in response to a standardized meal and work skills were evaluated. Paired samples t-tests were used to examine the differences in metabolic responses and work performance tasks between the conditions. Results: Pedal desk use required significantly less insulin to maintain glucose concentrations compared with STD condition (peak insulin concentration, 42.1 uU mL-1 vs 66.9 uU mL-1; P = 0.03; and area under the curve, 302.6 vs 441.8 uU min-1 mL-1; P 0.05). In addition, pedaling at a self-paced rate caused no adverse effects on work skills (P > 0.05). Conclusions: The PD resulted in lower postmeal insulin concentrations without an overall negative impact on work skills. Thus, the PD could have the potential to achieve public and occupational health goals in sedentary work environments.Peer reviewedCommunity Health Sciences, Counseling and Counseling Psycholog

Sensorimotor Function in Progressive Multiple Sclerosis

Background: A sensitive test reflecting subtle sensorimotor changes throughout disease progression independent of mobility impairment is currently lacking in progressive multiple sclerosis. Objectives: We examined non-ambulatory measures of upper and lower extremity sensorimotor function that may reveal differences between relapsing–remitting and progressive forms of multiple sclerosis. Methods: Cutaneous sensitivity, proprioception, central motor function and mobility were assessed in 32 relapsing–remitting and 31 progressive multiple sclerosis patients and 30 non-multiple sclerosis controls. Results: Cutaneous sensation differed between relapsing–remitting and progressive multiple sclerosis at the foot and to a lesser extent the hand. Proprioception function in the upper but not the lower extremity differed between relapsing–remitting and progressive multiple sclerosis, but was different for both upper and lower extremities between multiple sclerosis patients and non-multiple sclerosis controls. Foot-tap but not hand-tap speed was slower in progressive compared to relapsing–remitting multiple sclerosis, suggestive of greater central motor function impairment in the lower extremity in progressive multiple sclerosis. In addition, the non-ambulatory sensorimotor measures were more sensitive in detecting differences between relapsing–remitting and progressive multiple sclerosis than mobility assessed with the 25-foot walk test. Conclusion: This study provides novel information about changes in sensorimotor function in progressive compared with relapsing–remitting forms of multiple sclerosis, and in particular the importance of assessing both upper and lower extremity function. Importantly, our findings showed loss of proprioceptive function in multiple sclerosis but also in progressive compared to relapsing–remitting multiple sclerosis

Walking cadence (steps/min) and intensity in 21-40 year olds: CADENCE-adults

Background: Previous studies have reported that walking cadence (steps/min) is associated with absolutely-defined intensity (metabolic equivalents; METs), such that cadence-based thresholds could serve as reasonable proxy values for ambulatory intensities.Purpose: To establish definitive heuristic (i.e., evidence-based, practical, rounded) thresholds linking cadence with absolutely-defined moderate (3 METs) and vigorous (6 METs) intensity.Methods: In this laboratory-based cross-sectional study, 76 healthy adults (10 men and 10 women representing each 5-year age-group category between 21 and 40 years, BMI = 24.8 +/- 3.4 kg/m 2 ) performed a series of 5-min treadmill bouts separated by 2-min rests. Bouts began at 0.5 mph and increased in 0.5 mph increments until participants: 1) chose to run, 2) achieved 75% of their predicted maximum heart rate, or 3) reported a Borg rating of perceived exertion > 13. Cadence was hand-tallied, and intensity (METs) was measured using a portable indirect calorimeter. Optimal cadence thresholds for moderate and vigorous ambulatory intensities were identified using a segmented regression model with random coefficients, as well as Receiver Operating Characteristic (ROC) models. Positive predictive values (PPV) of candidate heuristic thresholds were assessed to determine final heuristic values.Results: Optimal cadence thresholds for 3 METs and 6 METs were 102 and 129 steps/min, respectively, using the regression model, and 96 and 120 steps/min, respectively, using ROC models. Heuristic values were set at 100 steps/min (PPV of 91.4%), and 130 steps/min (PPV of 70.7%), respectively.Conclusions: Cadence thresholds of 100 and 130 steps/min can serve as reasonable heuristic thresholds representative of absolutely-defined moderate and vigorous ambulatory intensity, respectively, in 21-40 year olds. These values represent useful proxy values for recommending and modulating the intensity of ambulatory behavior and/or as measurement thresholds for processing accelerometer data.Peer reviewedCommunity Health Sciences, Counseling and Counseling Psycholog

Affordable Remote Health Monitoring System for the Elderly Using Smart Mobile Device

Aging population has been growing as life expectancy increases. In the years to come a much larger percentage of the population will be dependent on others for their daily care. According to a recent report more than 11 million seniors live alone in the USA. These seniors may face serious consequences when they have an emergency situation. However health-monitoring systems are often not affordable for many seniors. The remote health monitoring system presented in this paper addresses the challenge to provide caregivers an emergency alert system for the elderly based on monitoring of their heart rates, breathing activities, and room temperature measurements. The device also allows the dependents to make on demand request for assistance. The remote communication is enabled through the cellular telephone services; so there is no special or additional subscription services needed. This is essential to make the device more affordable for the elderly. We expect that this affordable remote health-monitoring system can be used to help seniors who live alone be safer and healthier

Effects of Twenty Sessions Core Stability Exercise on Functional Movement and Balance

People often experience lower limb injury due to sport activities or falls in their daily life. Core stability exercise may contribute to prevent or minimize the chronic discomfort in skeletal muscle. PURPOSE: The purpose of this study is to investigate the effect of core stability exercise for subjects who have mild discomfort of the lower limb. METHODS: Participants (N=20, 32.3±8.6 yrs, male and female) were randomly divided in two different groups: 10 in the control group and 10 in the exercise group performing core stability exercise program. The core stability exercise consisted of ten main exercises including modified mat pilates program and took 30 minutes per session. Functional Movement test (Professional FMS Test Kit, USA), and Y balance test (Professional FMS Test Kit, USA) were measured before and after the 20 sessions of core stability exercise for 4 weeks. Data were analyzed with two-way ANOVA analysis of variance and LSD post hoc test. All values are expressed as mean (SEM). PRESULTS: There was no significant interaction effect between group and time for total FMS score. However, a significant time effect was observed in total FMS score (F=13.634, p=.005), and post-hoc analysis showed that total FMS score was significantly increased from baseline in the exercise group (p =.001). Y-balance test showed that there was a significant time effect on the left and the right lower body respectively (F= 10.216, p= .011; F = 11.870, p = .007) and post-hoc analysis showed that it increased from baseline in the exercise group (pCONCLUSION: These results indicate that 20 sessions core stability exercise positively effects the lower limb’s balance ability of people with mild discomfort

Effects of Point of Aim on the Accuracy and Eye Movement Behavior in Bowling: A Pilot Study

Background: A common research question in far-target aiming has been the importance and significance of the final visual fixation before movement initiation. In rolling tasks, such as 10-pin bowling, location of point of aim needs not be at the final target, the pins, but may be located at any point along the trajectory of the ball. Objective: Specific interest in the present experiment has focused on the relationship between visual point of aim and performance accuracy, and the relationship of visual control strategies utilized by expert performers. Methods: Skilled bowlers (N=7) performed 20 trials per condition concentrating on visual targets in different distances along the bowling lane (20, 40, 60 feet, and self-selected). Ball trajectory was tracked using a video based system and eye movement was measured using an eye tracking system. Results: Deviation of the ball from the visual target increased with visual target distance, while deviation of the ball from the pins was the lowest in the self-selected visual targets, followed by aiming at the pins. The final fixation duration before movement initiation was not associated with ball accuracy regardless of visual target locations. However, results demonstrated the association between final fixation duration task difficulty, that is, longer final fixation duration with increased visual target distance. Conclusion: The results indicate that visual fixations before movement initiation are uncharacteristically long while visual fixations just before the completion of the movement are relatively short

Effects of smartphone texting on the visual perception and dynamic walking stability

Mobile phone use while walking can cause dual-task interference and increases safety risks by increasing attentional and cognitive demands. While the interference effect on cognitive function has been examined extensively, how perception of the environment and walking dynamics are affected by mobile phone use while walking is not well understood. The amount of visual information loss and its consequent impact on dynamic walking stability was examined in this study. Young adults (mean, 20.3 years) volunteered and walked on a treadmill while texting and attending to visual tasks simultaneously. Performance of visual task, field of regard loss, and margin of stability under dual-task conditions were compared with those of single-task conditions (i.e., visual task only). The results revealed that the size of visual field and visual acuity demand were varied across the visual task conditions. Approximately half of the visual cues provided during texting while walking were not perceived as compared to the visual task only condition. The field of regard loss also increased with increased dual-task cost of mobile phone use. Dynamic walking stability, however, showed no significant differences between the conditions. Taken together, the results demonstrate that the loss of situational awareness is unavoidable and occurs simultaneously with decrements in concurrent task performance. The study indicates the importance of considering the nature of attentional resources for the studies in dual-task paradigm and may provide practical information to improve the safe use of mobile phones while walking