Context: Despite an association between foot structure and the incidence of lower limb injury in sport, few studies have measured the effects of neutral, pronated and supinated foot structures during dynamic activity. Furthermore, despite its widespread use as an injury prevention method, the effects of athletic taping on individuals with pronated and supinated foot structures are unclear. Objectives: To explore whether individuals with pronated and supinated foot structures have poorer lower limb neuromuscular control as measured by postural stability and muscle reaction time in comparison to those with neutral feet. Additionally, the effects of athletic taping on individuals with neutral, pronated and supinated foot structures on aspects of lower limb neuromuscular control are also examined. Subjects: All subjects used in this thesis were aged from 18 – 30 years and took part in at least two hours of exercise each week. Subjects were categorised in to groups according to navicular drop height measures; neutral 5 – 9 mm; pronated ≥ 10 mm; supinated ≤ 4 mm. Methods: Neuromuscular control was analysed in subjects with neutral, pronated and supinated feet using dynamic postural stability and muscular reaction time measures. These measures were then repeated with four athletic taping conditions (arch tape, ankle tape, proprioceptive tape and no-tape) both before and after a period of exercise. Results: Individuals with pronated and supinated foot structures were shown to have reduced postural stability in comparison to those with neutral foot structures during some dynamic tasks. Pronated and supinated foot structures also resulted in slower muscle reaction times in comparison to those with neutral feet during a tilt platform perturbation. No differences were identified between dominant and non-dominant limbs on subjects with neutral, pronated or supinated foot structures; however the high incidence of foot structure asymmetry did appear to result in differences between contralateral limbs in both postural stability and reaction time parameters. Arch and ankle taping resulted in increased neuromuscular control after application, yet these effects diminished after a period of exercise. Conclusions: The results of this thesis provide evidence to suggest that foot structure does affect lower limb neuromuscular control as measured by postural stability and muscle reaction time. In addition athletic taping has been shown to affect neuromuscular control on subjects with neutral, pronated and supinated foot structures both before and after exercise. These findings may have wide implications in sport where individuals with pronated and supinated feet may be more susceptible to injury in comparison to those with neutral feet.

1 Abstract Title: The effect of running with a load on postural stability. Objectives: The establishment of changes in postural stability after a 3 km maximum effort run with a 15 kg load. Research sample: The tested subject group was constitued by seven soldiers of the Army of The Czech Republic at the average age of 25,6 ± 2,1 years who are students of the Military specialization at the Faculty of sport and physical education of The Charles University. Methods: This master's thesis was drawn up as a observational study of theoretic empiric character, realised through intraindividual comparative analysis on a group of 7 subjects. Postural stability was examined with RS Footscan forceplate and clinical balance test U.S. Military Academy Stance Test. The run was realised on a treadmill, without and with a load. For statistical analysis nonparametric statistic tests of significance were used. Results: The results of relations between postural control changes and 3km run with a load of 15 kg display a deterioration of postural stability tested after the run. The extend of deterioration of postural stability after 3-km run with a load within tested group is similar to one after 3-km run of analogous intensity. Key words: run, load, postural stability, balance

It is well established that exposure to virtual motion environments (VME) can elicit postural instability (PI) in addition to motion sickness (MS). While research has found sex differences in motion sickness, the results of experimental studies are equivocal regarding these differences, and previous studies utilizing VME have failed to address the factor of sex differences in terms of hormonal fluctuations, which may also be instrumental in behavioral responses to VME, such as PI. The intent of this investigation was to determine whether exposure to VME, during various phases of the menstrual cycle (premenstrual, permenstrual, ovulation) would reveal sex differences in MS and PI during some phases, but not others. The first experiment involved men and women completing Daily Living Logs for a period of 40 days to provide a baseline for any sex differences (and for women, menstrual phase differences) in motion related activity and symptomatology. The second experiment involved 24 participants (6 men) viewing a rotating Archimedes spiral for a period of twenty minutes. Exposures were timed to place each woman in three phases of her menstrual cycle; men were exposed by yoking their exposure time to a female counterpart. Multiple measures of PI and MS were recorded before, after and during exposure. Results of the first experiment found no significant effects of sex or phase upon symptomatology, revealing no support for the theory of a reporting bias as influencing sex differences in MS or PI elicited in the laboratory. The second experiment found no significant effect of sex of phase upon any of the PI measures, but found significant interaction effects of sequence and phase, as well as sequence and sex, upon reported magnitude ratings of illusory self-motion perception. There were also significant effects of sex found upon measures of MS, with women reporting more discomfort to exposure to motion stimulation, as compared to men. There were no significant effects of phase upon any of the MS measures. While these findings show no support for a reporting bias influencing the sex differences found experimentally induced MS, it yields no evidence to support a hormonal influence on these differences.

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PURPOSE:. To determine the effects of blurring vision on whole-body center-of-mass (CM) dynamics and foot-clearance parameters in elderly individuals performing a single step up to a new level. METHODS:. Twelve healthy subjects (mean age, 72.3 +/-4.17 years) performed a single step up to a new level (heights of 73 and 146 mm). Trials were undertaken with vision optimally corrected and with vision diffusively blurred by light-scattering lenses (cataract simulation). CM and foot-clearance parameter data were assessed by analyzing data collected by a five-camera, three-dimensional (3-D) motion analysis system. RESULTS:. When vision was blurred, subjects took 11% longer to execute the stepping task (P < 0.05), mediolateral displacement of the point of application of the ground reaction force vector (i.e., weighted average of all pressures over the area in contact with the ground; the so called center of pressure, CP) decreased from 37.6% of stance width to 28.3% (P < 0.01), maximum distance between the mediolateral position of the CM and CP decreased by 9.8 mm (P < 0.01), and toe clearance (distance between tip of shoe and edge of step) increased in both the horizontal (28%) and vertical (19%) direction (P < 0.05). CONCLUSIONS:. These findings suggest that when vision was blurred, subjects used a twofold safety-driven adaptation: First, to increase dynamic stability they ensured that the horizontal position of their CM was kept close to the center of the base of support and second, they increased horizontal and vertical toe clearance while swinging their lead limb forward to reduce the risk of tripping.

Title: The Turkish Get-Up with a kettlebell from the point of view of developmental kinesiology Objectives: In the last couple of years the TGU has again entered the consciousness of the sporting public not just in the Czech Republic. Despite this there do not exist many studies that evaluate the effects of this exercise. It is a complex exercise, similar to the development line, during which one ascends from a lying down on the ground to a stan- ding position while holding a weight. This is why I chose tests for DSS. Postural muscle function develops vigorously during the first year of life. This is why the tests chosen are ones that evaluate the quality of the manner of connection and evaluate the function of the muscle during stabilization. The objective of this thesis is to confirm or overturn the statement that the TGU (Turkish Get-Up) positively affects the deep stabilizing system (DSS). The evaluation of data acquired will therefore provide the conclusion, whether the exercising of the TGU has a positive effect on the DSS. Methods: 8 people (4 women and 4 men) between the ages of 22-32 years participated in the stu- dy. They participated in a 6 week programme, exercising the TGU twice a week, 10 repetitions per exercise unit. Women used a kettlebell of 4 kg weight, men used a kettle- bell of...

Footwear can affect postural stability in individuals, particularly in elderly people. Aging-related decline in postural stability, particularly in the mediolateral (ML) direction, is a risk factor for falls and fall-related injuries among older adults. This study aimed to investigate the effects of high cushioned and minimal shoes on dynamic postural stability in ML during obstacle crossing in defined older and younger adults. Six healthy older adults (50–60 years old, body weight: 74.8 kg, body height: 168.0 cm) and six healthy younger adults (18–32 years old, body weight: 73.8 kg, body height: 174.8 cm) participated in the study. A Vicon motion analysis system with 10 optical cameras was used to capture the obstacle (20 cm height) crossing motion of the participants at 200 Hz, and ground reaction forces of obstacle crossing were collected at 1000 Hz. Motion data of obstacle crossing were collected at three shoe conditions, namely, minimal shoe, high cushioned shoe and barefoot (control). Data from five trials of obstacle crossing for each shoe condition were processed using Vicon Nexus software 2.11.0 and Matlab R2013b. Displacement and velocity of centre of mass (COM) in the ML direction, COM–centre of pressure (COP) ML separation, step length, step velocity, toe clearance, pre-horizontal distance, hip flexion angle and hip abduction angle during obstacle crossing were examined. One-way ANOVA with pairwise analysis showed that toe clearance was significantly larger in the high cushioned shoe conditions than in the minimal shoe and barefoot conditions in older adults (high cushioned shoes vs. barefoot: p = 0.019; cushioned shoes vs. minimal shoes: p = 0.031) and younger adults (high cushioned shoes vs. barefoot: p = 0.016; high cushioned shoes vs. minimal shoes: p = 0.000). No significant difference in the measures was found between the minimal shoe and barefoot conditions in each group. Compared with older adults, younger adults showed significantly larger step length in barefoot condition (p = 0.000) and minimal shoe (p = 0.016). Independent t-test for examination of the significant difference of the means of each measure when the shoe condition was changed showed that only step length and step velocity were significantly different between older and younger adults. When the shoe condition was changed from minimal shoe or barefoot to high cushioned shoe, older adults showed significantly bigger change in step velocity (10.04 ± 4.39 cm/s for older; 1.87 ± 0.81 cm/s for younger; p = 0.034) and step length (14.26 ± 6.99 cm for older; 2.086 ± 1.13 cm for younger; p = 0.041) than younger adults. This result indicates that older adults had 23% greater total range of step length and 12% greater total range of step velocity compared with younger adults when shoe condition changed. Moreover, older adults showed 16% smaller total range in their maximal COM-COP ML separations than younger adults when shoe condition changed. It is concluded that high cushioned shoes can influence dynamic postural stability in the ML direction during obstacle crossing in younger and older adults. The minimal shoe and barefoot conditions did not show significant influence on postural stability in the ML direction during obstacle crossing in older and younger adults. The minimal shoe on dynamic postural stability in the ML direction is not significant. Age differences in dynamic postural stability in the ML direction during obstacle crossing were found at the same shoe conditions. Moreover, when shoe condition was changed, shoe cushioning conditions affected postural stability to a larger extent in older adults compared with younger adults. The high cushioned shoe led to a more challenged postural stability in adults aged 50 to 60 than younger adults aged 18 to 32.

Background: Postural instability is a prevalent and deleterious consequence of aging. It is unclear how the occurrence of chronic pain augments balance issues as age progresses. Research question: We investigated how postural stability is influenced by aging and chronic pain. Methods: Fifty-five participants with and without recent chronic pain balanced on one foot while performing three tasks, a standard balancing task with no challenge, a mental task in which participants answered arithmetic questions while balancing on one foot, and a knot-tying task in which participants tied knots in a ribbon while balancing on one foot. General linear models were used to assess the relationship between age, sex, BMI, and pain category for the three different balancing tasks. In addition, a multivariate analysis of variance was used to test the effect of age and pain category on Hurst exponents from all of three different balancing tasks. Results: Our results show that aging changes the control strategy of balancing from less persistent to more repetitive. The strong feedback elements intrinsic to healthy stability ensure quick reactions and strong capacity to compensate for balance checks; this reactive state changes into a less reactive and more predictable balance strategy with age while balancing on one foot. Mental tasks during balancing also decreased the feedback in balancing strategy. Balance strategy during the knot-tying task was correlated with age, but unaffected by chronic pain. Overall, the chronic pain group had a worse balance strategy while performing the mental task in comparison with healthy people, but were not differentiable from controls in the standard or knot-tying tasks. Significance: Scores from balancing while engaging in cognitive tasks may provide evidence of health decline, and contribute to our knowledge about how pain affects feedback mechanisms.

Objective: We quantified, via complexity analysis, the postural stability of healthy people from a wide age range. Approach: Thirty-five healthy people aged 18-72 performed three tasks while balancing on one foot on a force plate: standard balancing task, mental task (balancing while answering basic arithmetic questions), and knot-tying task (balancing while tying two knots in a piece of ribbon). Mediolateral force trajectories were analyzed to determine control strategy via Hurst exponents, Lyapunov exponents, Kolmogorov complexity, root mean square, and phase-space plots. Main results: We found increased pattern repetition in balancing with increased age, as evidenced by the emergence of a double attractor pattern in phase-space plots and the increase of Hurst exponents with age from approximately 0.3 to 0.8. Significance: As people age, they tend to develop strong feed-forward control strategies for balancing, and lose the complexity of micro movements intrinsic to young age. There is an open-loop control strategy for balancing that emerges in older adulthood, and there are attractors inherent to balancing which begin to develop in middle age.

Functional limitation, postural stability, and muscle recruitment of different categories of obesity were evaluated while performing an assembly workstation task. Three workstations, those designed for the 5th, 50th, and 95th percentile workers based on anthropometric data tables, were included in the study. Functional limitation was measured using electro-goniometers and the maximum frontal functional reach (MFFR) evaluation to measure the difference in joint angles, forces plates were used to study the differences in postural stability, and EMG was used to evaluate the muscle recruitment of the soleus, frontal deltoid, and trapezius muscles. Also, a regression analysis was performed to evaluate if production efficiency rate could be predicted based on body mass index (BMI) group, gender, pace type, workstation configuration and 13 body dimensions. The results revealed that the body joint angles and muscle activation parameters were not significantly different based on the main factor BMI groups; however, significant differences were found in the two-way interactions of the BMI groups and the other factors. In regard to postural stability, the results indicated that the obese class 2 and obese class 3 groups anterior posterior sway was significantly larger than the normal weight groups. The results also revealed differences based on gender for the joint angles and muscle activation when performing the small part assemblies; however, postural sway was not affected by gender differences. Pace type (self –paced or timed-paced) significantly affected the postural stability and muscle activation when performing the work task. These differences in pace type were most prevalent when comparing the 95th percentile workstation configuration against the 5th percentile workstation configuration. In regards to productivity, gender, weight, waist-to-hip ratio and pace type seem to have a large role in the production efficiency rate. Even though an individual's BMI and the workstation layout were found to impact the body functional limitation and stability, the results showed that it doesn't affect production efficiency rate performance.