Boris Barbolyas, Michal Vajsábel, Cyril Belavý, Branislav Hučko and Ladislav Dedík
Human postural system is taken as complex biological system with specific input and output time characteristics, in this study. Evaluation of measured output characteristics is useful in medical diagnostics or in describing postural system disorders. System theory principle provide suitable basis for postural signals analysis. Participating volunteers were instructed to maintain quiet upright stance posture on firm support surface of stabilometric platform for 60s. Postural system actuation was realized by vibration stimuli applied bilaterally on Achilles tendons for 20s. Postural reaction signal, its time profile and static and dynamic characteristics were evaluated by Method of Developed Statokinesigram Trajectory (MDST).
Amine Ghram, James D Young, Rahman Soori and David G Behm
Static Bilateral Postural Stability
(French Posturology Association Normative Standards)
reps : repetitions
Postural control was evaluated using a force platform (SATEL ®; 40 Hz frequency, 12-bit A/D conversion, 480x480 mm, Blagnac, France), supported by three sensors, to record the displacement of the centerofpressure (CoP) ( Yahia et al., 2011 ). Postural control was examined before (PRE) and immediately after (POST) the fatiguing task. Participants were required to stand barefoot
Clint Hansen, Jacques LaRue, Manh-Cuong Do and Mark L. Latash
Making a step from a standing posture is accompanied by a consistent pattern of shifts of the centerofpressure (COP). In particular, the COP shows a shift backwards with a simultaneous transient shift towards the stepping foot, which is quickly reversed towards the supporting foot ( Breniere and Do, 1986 ; Couillandre et al., 2000 ; Crenna and Frigo, 1991 ; Halliday et al., 1998 ; Jian et al., 1993 ). Traditionally, postural preparation to stepping is analyzed within the anterior-posterior (AP) and medio-lateral (ML) coordinates. The ML
Javier Fernández-Rio, Luis Santos, Benjamín Fernández-García, Roberto Robles, Iván Casquero and Raúl Paredes
Lateral stance (surf)
Single stance – left leg
Single stance – right leg
30 / 10
Lateral stance (surf)
Note: Time in seconds
At pre- and post-test, all participants performed the same assessment tests in the same order. They were conducted in separate days: centreofpressure (CoP) and jump performance were evaluated on day 1, while acceleration and agility on day 2 (three days later). A regular soccer warm-up was performed prior to
Effects of a Physical Activity Program on Static Balance and Functional Autonomy in Elderly Women
Aim. The aim of study was to assess the effects of a physical activity program on static balance and functional autonomy in elderly women.
Materials and Methods. The sample was randomly divided into an experimental group (EG), submitted physical activity program, and a control (CG). Mean postural amplitude oscillations were measured in displacement from the center of pressure (COP), left lateral (LLD), right lateral (RLD), anterior (AD) posterior (PD) and elliptical (EA) areas by an electronic baropodometer. Functional autonomy was composed of: walking 10 m (10MW), rising from a sitting position (RSP), rising from a ventral decubitus position (RVDP), rising from a chair and moving about the house (RCMH) and putting on and removing a t-shirt (PRTS).
Results. Two-way ANOVA showed that amplitude oscillation of COP in RLD, AD, PD and EA of the EG was significantly lower (p < 0.05) than the oscillation obtained by the CG in the post-test. The RSP, RCMH, 10MW and RVDP tests showed that execution times in the RSP, RCMH, 10MW and RVDP tests of the EG were significantly lower (p < 0.05) than the times executed by the CG in the post-test.
Conclusion. These results show that the elderly in the EG improved balance and performance in the activities of daily living.
Grzegorz Juras, Kajetan Słomka, Artur Fredyk, Grzegorz Sobota and Bogdan Bacik
Evaluation of the Limits of Stability (LOS) Balance Test
The main objective of this study was the estimation of intrasession reliability of the limits of stability (LOS) test conducted on a force platform as an alternative measurement to standard posturography in quiet standing. Fifteen healthy adults took part in the experiment. The standardized measurement protocol of the LOS test was proposed. It consists of three phases - 1st phase - 10s of quiet standing, 2nd phase - the maximal forward leaning in a self paced manner, and 3rd phase - maintenance of maximal forward leaning position. The analysis of variance Friedman's ANOVA and Repeated Measures ANOVA/MANOVA was used to diagnose the differences between 10 consecutive trials of the LOS test. In order to establish reliability of the test, the intraclass correlation (ICC) procedure was used. We presented different ways of maximal center of pressure (COP) excursion estimates. The results of this study show no significant differences between the chosen parameters of the LOS test. Moreover, the measurement of the range of COP excursion, which is most commonly analyzed in such tests, showed to be quite reliable with ICC2,1 above .85. LOS test conducted along the standard procedure should be considered as a very useful method in clinical and research conditions. Still the specific parameters of the LOS test should be given more thorough insight, but it is a very good alternative to quiet standing posturography.
Gender Differences in Postural Stability Among Children
This study aimed to examine the gender differences in postural stability among 8-12 year-old children. Twenty-six children participated in this repeated measures study to measure the centre of pressure (COP) under one normal condition (CONTROL: hard surface, eyes open, and looking straight ahead) and two challenging sensory conditions (ECHB: eyes closed and head back; and EOCS: eyes open and compliant surface) in randomized order. Girls had significantly lower COP path velocity (COP-PV, p < 0.05, medium effect), smaller radial displacement (COP-RD, p < 0.05, medium effect), and lower area velocity (COP-AV, p < 0.05, medium effect) as compared to boys when the three conditions were pooled. Gender differences were found in the percentage changes in COP-RD during ECHB (p < 0.05, large effect) and EOCS (p < 0.05, medium effect), and in COP-AV during both ECHB and EOCS conditions (p < 0.05, medium effect). Postural stability performance of girls had higher correlations with age (-0.62 vs. -0.40), body mass (-0.60 vs. -0.42), foot length (-0.68 vs. -0.45), and physical activity level (-0.45 vs. 0.02), as compared to boys. Girls had better postural stability than boys but were more affected by altered sensory input information. Girls are more capable of integrating their sensory inputs, whereas boys treat each sensory input somewhat separately and rely more on somatosensory feedback. Exercises such as standing on unstable surfaces with eyes open instead of eye closed and head back are more beneficial to children's postural stability control system.
Andrzej Mastalerz, Tomasz Niźnikowski, Mariusz Buszta, Paweł Różański, Paweł Wiśniowski and Jerzy Sadowski
Introduction. Many studies have compared different backpack designs and their influence on the carrier; however, no data referring to school students aged 7-8 years are currently available. Therefore, the aim of the research was to assess the influence of backpack design on centre of pressure (COP) displacement and plantar force distribution in children during an upright stance. Material and methods. Nineteen school students (9 males and 10 females) volunteered for the study. Two Polish backpacks intended for school use were evaluated: backpack A, which had two main compartments, and backpack B, which had one main compartment. The backpack load was composed of books, binders, and regular school equipment. During the measurements, the subjects were asked to look ahead with the head straight and arms at the sides in a comfortable position and to stand barefoot on the F-Scan® sensors (Tekscan, F-Scan®) attached to the force platform (Kistler), carrying a load corresponding to 10% of their body mass. Results. The study found insignificant differences between the two backpack designs. Moreover, COP parameters increased significantly during an upright stance while carrying backpack B in comparison to the empty backpack condition. Additionally, we observed significantly higher values of plantar force distribution in the heel region for the condition without load and insignificantly higher ones for carrying backpack A. Conclusions. The results of the current study suggest that the differences between the two backpack designs are too marginal to be detected through COP displacement. Disturbances in plantar force distribution suggest a lack of posture control and a lower stability of the standing position with a backpack, but these disturbances were significant only when the backpack with one main compartment was used.
Raouf Hammami, David G Behm, Mokhtar Chtara, Aymen Ben Othman and Anis Chaouachi
When prescribing balance exercises to athletes in different sports, it may be important to recognize performance variations. Indeed, how athletes from different sports perform on balance tests is not well understood. The goal of the present study was to compare static balance and the role of vision among elite sprinters, jumpers and rugby players. The modified clinical test of sensory interaction on balance (mCTSIB) was used to assess the velocity of the center-of-pressure (CoP) on a force platform during a 30 s bipedal quiet standing posture in 4 conditions: firm surface with opened and closed eyes, foam surface with opened and closed eyes. Three-factor ANOVA indicated a significant main effect for groups (F=21.69, df=2, p<0.001, η2 = 0.34). Significant main effect of vision (F=43.20, df=1, p<0.001, η2 = 0.34) and surface (F=193.41, df=1, p<0.001, η2 = 0.70) as well as an interaction between vision (eyes open, eyes closed) and surface (firm and foam) (F=21.79, df=1, p=0.001) were reported in all groups. The subsequent Bonferroni-Dunn post hoc test indicated that rugby players displayed better static balance than sprinters and jumpers (p=0.001). The comparison of sprinters and jumpers did not reveal significant differences (p>0.05). The nature of the sport practiced and the absence of visual control are linked to modify static balance in elite athletes. Coaches and strength and conditioning professionals are recommended to use a variety of exercises to improve balance, including both exercises with opened and closed eyes on progressively challenging surfaces in order to make decisions about tasks and sensory availability during assessment and training.
Grzegorz Bednarczuk, Ida Wiszomirska, Jolanta Marszałek, Izabela Rutkowska and Waldemar Skowroński
Introduction. In elite sport, athletes are required to maintain appropriate body posture control despite a number of destabilising factors. The functions of body posture control are monitored by the central nervous system that constantly receives information from the vestibular and somatosensory systems as well as from the visual analyser. Visual impairment may contribute to a decrease in the level of motor abilities and skills; however, it does not prevent visually impaired individuals from taking up physical activity. Therefore, this study sought to assess the static balance of visually impaired goalball players and shooters. Material and methods. The study included 37 goalball players and 20 shooters. A force platform was used to assess static balance. The study participants performed tests: standing on both feet with eyes open (BFEO) and closed (BFEC) (30 s), single left- and right-leg stance with eyes open (SLEO and SREO) as well as single left- and right-leg stance with eyes closed (SLEC and SREC). Statistical analyses were carried out using the following parameters: centre of pressure (CoP) path length [cm], CoP velocity [m/s], and the surface area of the stabilogram [cm2]. Results. No significant differences were found between goalball players and shooters in static balance levels. However, such differences were observed after taking into account the number of athletes who were capable of performing particular tests. Conclusions. The findings indirectly confirm that there is a correlation between the type of physical activity and balance levels in visually impaired individuals. Further research ought to include tests performed on an unstable surface.