THE INFLUENCE OF HEAD POSITION ON POSTURAL STABILITY

The influence of head position on the stance stability was studied in a set of 51 healthy university students (men, n = 21; women, n = 30) in a bipedal stance and the stance on left and right leg respectively. The head position was standardised by observation of a fixed point through dominant and nondominant eye. Two AMTI force plates and 3D kinematic analysis (APAS system) were used for the evaluation of posture stability. No significant differences were found in the bipedal stance in all test procedures. The differences in the head positions have statistically and significantly influenced only the posture stability by stance on the left leg in both groups (dominant eye right and left) in contrast to the stance on the right leg where the differences were not statistically significant

Effect of Gait Imagery Tasks on Lower Limb Muscle Activity With Respect to Body Posture

The objective of this study was to evaluate the effect of gait imagery tasks on lowerlimb muscle activity with respect to body posture. The sitting and standing position and lower limb muscle activity were evaluated in 27 healthy female students (24.4±1.3 years, 167.2±5.2 cm, 60.10±6.4 kg). Surface electromyography was assessed during rest and in three different experimental conditions using mental imagery. These included a rhythmic gait, rhythmic gait simultaneously with observation of a model, and rhythmic gait after performing rhythmic gait. The normalized root mean square EMG values with respect to corresponding rest position were compared using non-parametric statistics. Standing gait imagery tasks had facilitatory effect on proximal lower limb muscle activity. However, electromyography activity of distal leg muscles decreased for all gait imagery tasks in the sitting position, when the proprioceptive feedback was less appropriate. For subsequent gait motor imagery tasks, the muscle activity decreased, probably as result of habituation. In conclusion, the effect of motor imagery on muscle activity appears to depend on relative strength of facilitatory and inhibitory inputs

Detection of mild cognitive impairment during locomotion after stroke

Mírná kognitivní porucha s sebou nese vysoké riziko vzniku demence. Existuje stále více důkazů, že kognitivní pokles má za následek zhoršení lokomočních parametrů. Ačkoli jsou obvykle spojeny s pozdějšími stadii demence, pokles výkonnosti chůze může být detekován mnohem dříve. Možným směrem v odhalení mírné kognitivní poruchy u osob po cévní mozkové příhodě je sledování lokomočních parametrů za podmínek dvojího úkolu.Mild cognitive impairment entails a high risk of developing dementia. There is growing evidence that cognitive decline results in the deterioration of gait patterns. Though it is commonly associated with the later stages of dementia, a decline in gait performance may be detected much earlier. Observation in a dual task paradigm might improve the detection of mild cognitive impairment

The Ralations between Variability and Muscle Fatigue in Prototype Movements

Svalová únava je mnohostranný jev zahrnující periferní, centrální a také kognitivní faktory. V centrální úrovni dochází k rozvratu neurotransmiterové regulace, a tak proces motorického učení může výrazně prospět k opětovnému vyrovnání zatíženého systému. Díky zajištění variabilního projevu, umožňujeme motorickým vzorům se účinně přizpůsobit na specifické požadavky vnějšího a vnitřního prostředí, aniž by se změnil požadovaný cíl či záměr pohybu. Během našeho experimentu se snažíme objektivně zhodnotit vliv kognitivních funkcí na progresi či regresi svalové únavy. Z množství prototypových pohybů byla pro testování vybrána vysoce náročná pozice – statický dřep Wall Sit. Ten nás informuje o svalové zdatnosti v závislosti na čase a zároveň přináší poznatky o variabilitě zapojení svalových skupin dolních končetin během nástupu svalové únavy. Na základě tohoto dogmata vztahu mezi variabilitou a svalovou únavou potvrzujeme rozdíl na hladině statistické významnosti (p < 0,05), kdy došlo ke zlepšení výkonu z pohledu času za vlivu kognitivní zátěže. Výsledky experimentu tak potvrzují významný a zároveň pozitivní vliv externího zaměření pozornosti, kdy jsme potvrdili oddálení projevu svalové únavy.Muscle fatigue represents wide-ranging phenomenon involving peripheral, central and also cognitive factors. At the central level, it leads to a collapse of neurotransmitter regulation and so the motor learning process can become significantly beneficial for restoration of the system under pressure. Because of ensuring variable behaviour, we enable the motor patterns to adapt effectively to specific requirements of an external and internal environment, without changing the objective or intention of the movement. In our experiment we try to evaluate objectively the impact of cognitive functions on progression and regression of muscle fatigue. To evaluate this issue adequately, a physically demanding posture – a squat Wall Sit, has been chosen from a range of prototype movements. Wall Sit provides information about muscle capability depending on time and also offers findings about variability of the engagement of lower limbs muscle group during the beginning of muscle fatigue. On the basis of the relation dogma between variability and muscle fatigue, we confirm the difference at the level of statistical significance (p < 0,05), when regarding the time during influence of cognitive load, the performance improved. The results of the experiment confirm a significant and at the same time positive impact of an external focus of attention, when we confirmed delay in the beginning of muscle fatigue