Static and dynamic single leg postural control performance during dual-task paradigms

ABSTRACTCombining dynamic postural control assessments and cognitive tasks may give clinicians a more accurate indication of postural control under sport-like conditions compared to single-task assessments. We examined postural control, cognitive and squatting performance of healthy individuals during static and dynamic postural control assessments in single- and dual-task paradigms. Thirty participants (female = 22, male = 8; age = 20.8 ± 1.6 years, height = 157.9 ± 13.0 cm, mass = 67.8 ± 20.6 kg) completed single-leg stance and single-leg squat assessments on a force plate individually (single-task) and concurrently (dual-task) with two cognitive assessments, a modified Stroop test and the Brooks Spatial Memory Test. Outcomes included centre of pressure speed, 95% confidence ellipse, squat depth and speed and cognitive test measures (percentage of correct answers and reaction time). Postural control performance varied between postural control assessments and testing paradigms. Participants did not squat..

The Relationship between Vertical Jump Scores and Peak Force Measurements of an Isokinetic Leg Press

This study evaluated potential correlations between related closed kinematic chain strength measurements on a Kin-Com isokinetic machine and a functional strength test. The correlation between standing vertical jump height and isokinetic leg press measurements were statistically analyzed. The following measurements were obtained from 22 subjects (mean age of 24.4 years): a body weight measurement, a vertical jump score, and the force measurements of an isokinetic leg press at 90°/second on each leg. Pearson correlation coefficients were significant (p \u3c .001) when power quotient scores (vertical jump height multiplied by body weight) were compared to leg press results. However, second-order partial correlation coefficients did not find a significance (p \u3e .005) between vertical jump scores and isokinetic leg press results when weight and gender were considered. A significant difference (p \u3c .001) existed between left leg press and right leg press measures. Although isokinetics are useful for lower extremity assessment, this study found that the isokinetic leg press may not be appropriate in determining functional ability

Interaction techniques for older adults using touchscreen devices : a literature review

International audienceSeveral studies investigated different interaction techniques and input devices for older adults using touchscreen. This literature review analyses the population involved, the kind of tasks that were executed, the apparatus, the input techniques, the provided feedback, the collected data and author's findings and their recommendations. As conclusion, this review shows that age-related changes, previous experience with technologies, characteristics of handheld devices and use situations need to be studied

Comparison of the Balance Error Scoring System and the NeuroCom Sensory Organization Test in healthy, physically active adults

Concussion is a common occurrence in athletics and requires a comprehensive exam, including assessment of postural stability. The Balance Error Scoring System (BESS) is recommended by the NCAA/NATA for sideline evaluation. The NeuroCom Sensory Organization Test (SOT) is a dynamic posturography assessment tool that uses somatosensory and visual input to challenge the somatosensory, visual and vestibular systems. Due to significant negative outcomes associated with mismanaged concussions, a sideline assessment must appropriately measure each component of postural stability. Purpose: To examine the relationship between the BESS and the SOT clinical scores and kinetic variables. Methods: Nineteen healthy, physically active young adults (22.162.59 years, 168.5622.24cm, 73.2415.28kg) were tested using the BESS and the SOT in a single session. The BESS tested six-conditions, including bilateral, single leg and tandem stances, each assessed on firm and foam surfaces. The SOT tested six-conditions, including eyes open, eyes closed and sway surround, each tested on a stable and sway support surface. Overall and condition error scores from the BESS were compared to SOT composite score and somatosensory, visual and vestibular component scores. Kinetic variables of standard deviation of vertical ground reaction force (SDvGRF) and total sway were calculated for each condition of the BESS and the SOT and compared between assessments. Pearson and Spearman correlation coefficients were calculated. Significance was set at P<0.05 a priori. Results: The clinical scores of the BESS and the SOT demonstrated one significant association (SOT somatosensory component and BESS tandem on firm error score, r=-0.493, p=0.032). In contrast, significant correlations were observed between several BESS and SOT SDvGRF variables (r=0.458 – 0.760, p<0.05) and sway variables (r=0.465 – 0.681, p<0.05). Conclusion: Based on these results, the error scoring system of the BESS should be reevaluated to determine if magnitude of error scoring would increase association with SOT clinical scores. Additionally, there may not be a significant vestibular challenge with the BESS associated with inaccurate visual input. Future research should investigate potential modifications to improve the BESS for clinical use in concussion assessment to create a more comprehensive tool that incorporates magnitude of error scoring and a heightened vestibular challenge through inaccurate visual input

3D Knee Kinematics and Kinetics With Visual Disruption in Subjects With ACL Reconstruction

BACKGROUND AND PURPOSE: The anterior cruciate ligament (ACL) is a commonly ruptured ligament among male and female athletes. Women are at a higher risk of ACL injuries compared to men. The leading cause of female ACL injuries has been identified as non-contact mechanisms. Several risk factors for injury among females that have been theorized include: quadriceps/hamstring activation pattern and force production, greater dynamic knee valgus, hormonal influenced laxity and anatomical gender variation. The purpose of this research was to analyze three dimensional (3D) kinetic and kinematic dynamic landing patterns at the knee between ACL reconstructed and healthy females and any interaction effects of visual disruption. METHODS: Seventeen healthy female subjects (25.3± 6 y) and 17 female subjects with an ACL reconstruction (26.5± 6.3 y) were studied. A 3D electromagnetic system measured knee position during a cutting maneuver from an athletic stance position. Anatomic boney landmarks on the occiput, sacrum, femur and tibia were digitized for capture. Subjects began on a force plate and were instructed to catch a ball and cut immediately left or right as indicated by a specific tone, which was randomized (40 trials). Vision was randomly disrupted via shutter glasses for either one second at the beginning of the cutting maneuver or was left intact for the duration of the movement. A two-way repeated measures ANOVA analyzed the differences between healthy and ACL reconstructed subjects and intact vision versus disrupted vision. RESULTS: The results indicate significant differences exist between subjects with ACL reconstruction and healthy subjects for flexion, adduction, and external rotation knee angles and extension, abduction, and internal rotation moments. Significant interactions of group and vision conditions also exist for flexion, adduction, and external rotation knee angles. Vision alone displayed no significant differences for all subjects. CONCLUSION: Years later, subjects with ACL reconstructions continue to display different knee kinematics and kinetics that could increase their risk for re-injury or injury of other leg. Furthermore, visual disturbances have significant effects on ACL reconstructed knee angles and moments when landing compared to healthy subjects. These results support continued movement related rehabilitation with visual disturbances for ACL reconstructed patients

Relationship between core stability and shoulder injuries in athletes

Core stability (neuromuscular control and muscle capacity of the trunk and pelvis) is theoretically linked to optimal shoulder function during sports-specific tasks despite limited evidence to support its use for the prevention or rehabilitation of extremity injuries in athletes. Impairments in core stability could theoretically result in less than optimal performance and abnormal force dissipation to the shoulder complex that could potentially lead to upper extremity injuries in athletes. Lower extremity postural control is also associated with athletic function and may be associated with upper extremity injuries. Clinical measures of core stability have not been validated against lab-based measures of core neuromuscular control. This has resulted in several knowledge gaps that hinder clinical identification of core stability deficits in athletes, as well as the determination of the role that core stability has in athletic injuries. The specific aims of this study are to 1) determine the strength of the association between clinical and lab-based measures of core stability in the athletic population and 2) identify the clinical and lab-based measures of core stability that are significant predictors of shoulder injuries in athletes. Eighty athletes (55 males, age: 21.2 + 3.3 years, 40 with shoulder pain) completed clinical and lab-based tests of core stability that assess aspects of both muscle capacity and neuromuscular control of the trunk and pelvis, as well as lower extremity postural stability. Athletes competed at a club, varsity, or competitive level, and were matched by age, gender, BMI, and sport type. Spearman’s rho (ρ) correlations were used to assess relationships between clinical and biomechanical measures of core stability. MANOVAs were used to assess differences between measures of core stability and lower extremity postural stability between groups. There were significant small-medium correlations between clinical and biomechanical measures of core stability. There were no statistically significant differences between athletes with and without shoulder injuries for the clinical or biomechanical core stability measures or clinical or biomechanical lower extremity postural stability measures. Our findings suggest that the clinical tests assessed require some static core neuromuscular mechanisms, although these tests primarily assess of core muscle capacity. Although core stability is widely incorporated in rehabilitation of athletes with shoulder injuries, these athletes may not present with impairments in core stability or lower extremity postural stability.Ph.D., Rehabilitation Sciences -- Drexel University, 201

Factors Affecting Block Performance From The Omega OSB11 Starting Platform

In 2009, the international governing body of swimming approved the use of the Omega OSB11 platform. It features a back foot kick plate that can be shifted into five positions. The purpose of this thesis is to identify set stance characteristics of the track start that may produce a faster start from the OSB11. The first project evaluated: optimal kick plate location, its relationship to segment lengths, and rear foot position as high and low on the kick plate. The swimmers demonstrated significantly greater horizontal take-off velocity and decreased time to 2 m with the rear foot in the high position. However, no moderate or strong relationships were detected between optimal kick plate location and segment lengths. The second study examined the power limb position. The swimmers were tested for limb power using the single-leg triple hop for distance. They had a significantly greater horizontal take-off velocity when the power limb was placed at the front edge of the platform in the track start. The third study examined optimal, rear- and front-weighted center of mass (COM) location in the set stance. The rear-weighted start had a significantly greater horizontal take-off velocity and reaction time than the front-weighted. However, front-weighted track starts showed a significantly shorter block time than in the rear-weighted position. Most swimmers in the group demonstrated optimal performance when the COM locations were in a mid-weighted stance. The final project compared: coached and kinetic feedback (round 1), and the two forms of feedback in different orders (round 2) on 2 m time performance. After the first round, the kinetic group showed a significant increase in time but no significant change was found in the coached group. After the second round, there were no significant differences between groups. However, each group demonstrated a significant increase in time from the pre-test. Overall the thesis suggests that changes in start stance can impact performance. In addition, optimal positioning may also be unique to each swimmer which requires testing, and feedback and practice should be routine. The findings of this thesis support the need for future work to establish methods of determining optimal start positions for individual swimmers

Master of Science

thesisComputing and data acquisition have become an integral part of everyday life. From reading emails on a cell phone, to kids playing with motion sensing game consoles, we are surrounded with sensors and mobile devices. As the availability of powerful mobile computing devices expands, the road is paved for applications in previously limited environments. Rehabilitative devices are emerging that embrace these mobile advances. Research has explored the use of smartphones in rehabilitation as a means to process data and provide feedback in conjunction with established rehabilitative methods. Smartphones, combined with sensor embedded insoles, provide a powerful tool for the clinician in gathering data and may act as a standalone training technique. This thesis presents continuing research of a sensor integrated insole system that provides real-time feedback through a mobile platform, the Adaptive Real-Time Instrumentation System for Tread Imbalance Correction (ARTISTIC). The system interfaces a wireless instrumented insole with an Android smartphone application to receive gait data and provide sensory feedback to modify gait patterns. Revisions to the system hardware, software, and feedback modes brought about the introduction of the ARTISTIC 2.0. The number of sensors in the insole was increased from two to 10. The microprocessor and a vibrotactile motor were embedded in the insole and the communications box was reduced in size and weight by more than 50%. Stance time iv measurements were validated against force plate equipment and found to be within 13.5 ± 3.3% error of force plate time measurements. Human subjects were tested using each of the feedback modes to alter gait symmetry. Results from the testing showed that more than one mode of feedback caused a statistically significant change in gait symmetry ratios (p < 0.05). Preference of feedback modes varied among subjects, with the majority agreeing that several feedback modes made a difference in their gait. Further improvements will prepare the ARTISTIC 2.0 for testing in a home environment for extended periods of time and improve data capture techniques, such as including a database in the smartphone application

Enhancing the mechanical efficiency of skilled rowing through shortened feedback cycles

In elite level rowing competition, the average velocities of medallists differ by less than 1 % over 2000 m. Nations place sporting excellence in high regard and this magnifies the importance of success. As a result, sports science and technology is increasingly used to achieve marginal performance gains. This research considers how to advance biomechanical analysis and skills training provision with a particular focus on the technical and practical delivery of real-time feedback to coaches and athletes, thereby shortening the amount of time between feedback cycles. Underpinning any biomechanical feedback intervention, validated determinants of performance are required. Previous research revealed that, while gross biomechanical measures such as athlete power, stroke rate and stroke length have previously been used as key determinants of performance, elite athletes are nowadays performing within expected ranges and therefore it is no longer possible to easily differentiate crews using these measures alone. This thesis describes workshops held with elite coaches to investigate biomechanical efficiency where the outcomes led to a focus on how a boat accelerates and decelerates during a stroke and hence how the boat's velocity fluctuates. Novel metrics are proposed to quantify aspects of a stroke cycle and used to analyse an elite data set, collected using a standardised protocol. It is shown that individual elite rowers can be successfully differentiated and benchmark values of performance are presented. Consideration of previous research suggests that there is currently no suitably functional and flexible biomechanical real-time feedback system to deliver complex skills training in rowing. Therefore, this thesis describes the research that has led to the development and evaluation of new technology to deliver visual and audible interfaces that support the delivery of concurrent and terminal feedback in water and land-based environments. Coaches and athletes were involved throughout the design process to optimise system suitability and encourage adoption. The technology empowers a coach to intricately manipulate feedback provision, thereby promoting motor control and learning theory best practice. Novel insights relevant to designing interactive systems for use within an elite sporting population are also discussed. This research presents an end-to-end strategy for the applied delivery of real-time feedback to skilled rowers bringing together engineering and social science disciplines. A land-based case series reveals that while statistically significant skill learning was not achieved, participants acquired sport specific technical awareness and heightened motivation as a result of the skills training intervention. Existing motor learning literature was tested as part of the study with a key finding being the lack of support for audible display of stroke acceleration through frequency modulation. Study limitations were identified that explain the lack of an effect of skills training on rower efficiency. The study also acted as a validation of the use of a land-based simulator to monitor and manipulate stroke velocity and a validation of the candidate feedback interfaces that had been implemented. As of result of this work, rowing coaches are able to evaluate their athletes in a novel way, achieving a deeper appreciation of their biomechanical efficiency. Upon identifying athletes with a need for technical development, coaches can intervene with the proposed methodology of skill development making use of the new technologies developed to deliver performance gains. This methodology would achieve enhanced validity through a deeper understanding of the reliability of the new metrics and their relationship to boat speed. Future attempts to test for skill learning should build upon the findings made in this work and, in due course, technology and theory should combine to deliver terminal feedback training during water-based rowing