Dynamic postural stability in blind athletes using the biodex stability system

Neuronal Control of Posture in Blind Individuals

The control of posture is guided by the integration of sensory information. Because blind individuals cannot apply visual information to control posture as sighted individuals do they must compensate by the remaining senses. We therefore hypothesize that blind individuals alter their brain activation in the sensorimotor cortex during postural control to compensate for balance control without vision by the increased integration of somatosensory information. Ten blind and ten sighted (matched) individuals controlled posture during conditions with (I) eyes closed / open, and (II) stable / unstable surface conditions. Postural sway was recorded by applying a pressure distribution measuring plate. Brain activation was collected by functional Near InfraRed Spectroscopy (fNIRS) above motor-sensory cortices of the right and left hemispheres. Blind individuals showed significantly increased postural sway when balancing with open eyes on an unstable surface and when compared to sighted individuals. Whereas blind individuals showed significantly increased brain activation when balancing with open eyes on stable and unstable surface conditions, sighted individuals increased their brain oxygenation only during closed eyes and unstable surface conditions. Overall conditions, blind individuals presented significantly increased brain activation in two channels of the left and right hemispheric motor-sensory cortex when compared to sighted individuals. We therefore conclude that sighted individuals increase their brain oxygenation in the sensorimotor cortex during postural control tasks that demand sensory integration processes. Blind individuals are characterized by increased brain activation overall conditions indicating additional sensory integration during postural control. Thus, the sensorimotor cortex of blind individuals adapts to control posture without vision.

The usefulness of balance test in preseason evaluation of injuries in amputee football players: a pilot prospective observational study

Background

Low balance ability is generally associated with an increased risk of ligament injuries. It seems that assessing the level of stability in amputee football players can help evaluate the accompanying risk of sports injuries. Thus, the study aimed to examine the usefulness of the balance test in preseason evaluation by calculating between-group differences in stability parameters between injured and non-injured amputee players.

Methods

The study was designed as a pilot prospective observational study. Twenty-five elite amputee football players representing the Polish National Team and the highest division in Polish League completed one-leg preseason balance tests on the Biodex Balance System before the start of the football season. All players in this study were male, with an average age of 29 years (SD = 7.9), a stature of 174.2 cm (SD 5.2) and a body mass of 80.1 kg (SD = 13.1). Then, players were prospectively observed over one football season, and lower leg injury data were prospectively collected through the nine months. The between-group differences were tested using the non-parametric Mann-Whitney U test for players who sustained an injury (yes) and those who did not within the analysed season (no). Overall (OSI), medial-lateral (MLSI), and anterior-posterior stability index (APSI) were analysed as primary outcomes.

Results

The preseason values of the balance tests were not predictive (p > 0.05) regarding sustaining an injury during the season. No between-group differences were noted for any analysed outcomes (p values ranged from 0.093 to 0.453).

Conclusions

Although static balance tasks offer a chance to make a preliminary assessment of injury prediction in amputee footballers, in overall, the balance test results cannot be regarded as the sole predictive injury risk factor in amputee football.

Physical activity and sport practice to improve balance control of visually impaired individuals: a narrative review with future perspectives

Visual disability negatively impacts balance, everyday self-efficacy, and mobility and often leads affected subjects to perceive physical exercise as a burdensome challenge thus discouraging them from practicing. Despite the well-proven benefits of regular physical activity in visually impaired people, especially addressing postural control, there are no specific guidelines and most of the available literature seems to be flawed by critical issues. Given the wide heterogeneity and the multidimensional needs of this population, a more realistic and target-specific perspective is needed in order to properly investigate and promote exercise practice and adherence for balance improvement. On this basis, through a critical overview of the recent literature, the present article aimed to enrich the current knowledge about this topic by providing innovative suggestions, both practical and methodological, and specifically deepening the disability-related deficits and peculiarities of different age ranges. Moreover, since a multidisciplinary approach is advisable when designing and leading exercise protocols tailored to visually impaired individuals, such innovative hints also highlighted the central role of the adapted physical activity specialist, hence contributing to foster its official professional recognition and involvement in this field.

Attack and Defense Performance in Goalball: A Proposal for Throwing, Balance and Acoustic Reaction Evaluation

Goalball is a sport for visually impaired athletes, where the roles of attack and defense change continuously during the game. Performance evaluation should consider the variables that determine the throwing and the stop and clearance of the ball. The aim of this study is to evaluate the precision and velocity of the ball throwing in goalball, besides core stability and balance as variables that determine an optimal throwing. Moreover, a novel acoustic reaction time is applied to analyze the defense performance. Eight goalball players (33 ± 9 years old; 77.8 ± 22.7 kg; 174 ± 13 cm; 10 ± 5 years of experience) were recruited to assess ball velocity, with a radar gun, and throwing accuracy. Anthropometry, static balance, and core stability were assessed using a computerized pressure platform. Acoustic reaction time was measured with a photoelectric system. A significant positive correlation was found between throwing speed and the years of experience (Ƿ = 0.714, p = 0.047), height (Ƿ = 0.786, p = 0.021), dominant leg surface area of the stabilogram (Ƿ = 0.738, p = 0.037), and non-dominant leg center of pressure mean velocity (Ƿ = 0.714, p = 0.017). In the present pilot study, height and years of experience are correlated to throwing velocity. This is also the first test proposal to assess throwing precision and complex acoustic reaction in goalball players, which could be used to assess the level of performance in future studies.

Postural control and risk of falling in people who are blind: The effect and durability of perturbation and vestibular exercises

The aim of this study was to compare the effect and durability of perturbation and vestibular exercises on balance and the risk of falling in people with visual impairment (VI). Thirty-six men with VI were divided into three groups, including a control and two experimental (perturbation and vestibular) groups. The experimental groups performed perturbation and vestibular exercises for 4 weeks and three sessions per week. Biodex balance system was used to assess balance and falling risk before and after training interventions. To evaluate the effects within and between groups at three levels of measurement: pre-test, post-test, and durability effect between three groups, repeated measures analysis of variance (ANOVA) and one-way ANOVA were used. Repeated measures ANOVA test showed that both experimental groups showed significant improvements in static balance, dynamic balance, and falling risk. In comparison between the groups, the results showed that in the post-test and durability stages, there was a significant difference between the groups and the perturbation exercise group had a greater effect on the dependent variables. Due to the effectiveness of exercises, it is recommended that people with VI pay attention to balance-based perturbation exercises to strengthen the somatosensory system and vestibular exercises to strengthen the vestibular system.

Examination of the Relationship Among Balance, Physical Activity, and Anthropometry in Athletes With Visual Impairments

Introduction

Although it is well documented in the literature that individuals with visual impairments have low physical activity levels and impaired body compositions and postural controls compared with peers without vision loss, the relation between these parameters in athletes with visual impairments is unknown.

Research Question

Here, we (i) evaluated the physical activity levels, balance measures, and anthropometry parameters in athletes with visual impairments and peers without vision loss controls and (ii) compared these variables between the two groups.

Methods

We designed a retrospective observational study with parallel groups conducted on 33 athletes with visual impairments and 33 sighted controls matched for age and sex. We also utilized a questionnaire about physical activity levels and assessed static balance for 4 conditions (eyes-open firm surface, eyes-closed firm surface, eyes-open foam surface, and eyes-closed foam surface) and anthropometry.

Results

In athletes with visual impairments, body composition, body mass index (BMI), physical activity level, and static balance parameters revealed no significant relationship ( p > .05), whereas eyes-open and -closed firm and foam surface conditions were positively related with physical activity at a moderate level ( r = 0.39, r = 0.38, p < .05, respectively). Moderate-intensity and high-intensity physical activity was positively associated with fat-free mass ( r = 0.82, r = 0.68, p < .01, respectively) and negatively related with body mass, fat %, and fat mass ( r = −0.67, r = −0.52, r = −0.72, r = −0.66, r = −0.50, r = −0.50, p < .01, respectively). Athletes with visual impairments presented lower static balance than the sighted controls for three conditions, while eyes-closed foam surface scores were similar in both groups. The physical activity levels were higher for athletes with visual impairments ( p < .05). However, we found no difference in the body composition and BMI between two groups ( p > .05).

Discussion

Sports participation from individuals with visual impairments is related to higher physical activity levels, resulting in better anthropometric profile. The balance control was not related to physical activity levels in athletes with visual impairments.

Are Gait Biomechanics Related to Physical Activity Engagement? An Examination of Adolescents with ASD

PURPOSE

Adolescents with autism spectrum disorder (ASD) rarely meet physical activity (PA) guidelines, thus not reaping associated health benefits. Although many barriers exist, abnormal or inefficient gait biomechanics could negatively impact engagement in PA. This study has two purposes: first, to compare total body mechanical work between adolescents with ASD and neurotypical age, sex, and body mass index matched controls, and second to determine whether gait biomechanics are significantly related to engagement in PA.

METHODS

Twenty-five adolescents (age 13-18 years) with ASD and seventeen neurotypical controls (eight with ASD had no match) participated in the study. Three-dimensional motion capture and force platforms were used to record and analyze gait biomechanics at self-selected speeds and a standardized 1.3 m/s. Total body mechanical work (sum of joint works across lower extremity, low back, torso, and shoulders) was compared between groups (n = 17 for each) and speeds using a mixed model analysis of variance. Average daily light (LPA), moderate to vigorous (MVPA), and total PA was recorded for the entire dataset with ASD using triaxial accelerometers worn for one week. Regression analyses were performed between work, stride time variability, speed, and stride length with each PA variable.

RESULTS

Adolescents with ASD generated 9% more work compared to the controls (p=0.016). Speed and stride length were significant regressors of LPA, MVPA, and total PA, explaining greater than 0.20 variance (p<0.02 for all regressions).

CONCLUSION

Although adolescents with ASD walked with significantly greater work, the complex full-body variable is not significantly related to engagement in PA. In agreement with research spanning multiple populations and ages, speed and stride length are indicative of PA engagement in adolescents with ASD.

Gender differences in postural balance, physical activity level, BMI, and body composition in athletes with visual impairment

The aim of this study was to examine the gender differences in postural balance, physical activity (PA), and body mass index (BMI) and body composition in visually impaired (VI) athletes. A total of 66 athletes took part in this study. After anthropometric measurements, the PA level was assessed by the International Physical Activity Questionnaire-Short Form. The modified Clinical Test of Sensory Integration and Balance tool was used to assess postural balance in four standing conditions: (1) eyes-open on a firm surface, (2) eyes-closed on a firm surface, (3) eyes-open on a compliant surface, and (4) eyes closed on a compliant surface. Findings revealed gender differences in anthropometric measurements ( p < .05). No statistically significant differences were found in fat mass and fat free mass between sighted male and VI male athletes and between sighted female and VI female athletes ( p > .05). Weekly, high and moderate PA levels as well as walking were found to be different across the four groups ( p < .05). Assessment of postural balance in four standing conditions revealed no gender differences in sighted athletes ( p > .05). Postural balance scores in conditions 1 and 3 showed significant gender differences ( p < .05), whereas conditions 2 and 4 showed no gender differences in athletes with VI ( p > .05). Gender-matched differences were also apparent in conditions 1 and 3, revealing that VI male and female athletes scored worse in these conditions than their sighted male and female counterparts ( p < .05). There is a delay in balance parameter in VI athletes even if their fitness levels are similar with their sighted counterparts. The present findings could also be useful for gender-specific training session preparations in VI sports.

Changes in plantar load distribution in legally blind subjects

We investigated the impact of visual impairment on balance control. We measured the center of pressure (COP) between the two feet and plantar surface pressures on each foot in 18 normal-sighted participants and compared their data with measures from 18 legally blind participants, either acquired or congenital. Pressures were measured in open- and closed-eye conditions using a baropodometric resistive plate. In the eyes-open condition, there were no differences between the sighted and legally blind groups in COP displacement. However, participants with visual loss had significantly increased pressures in two metatarsal regions (M1 and M2 zones) of the plantar surface in both viewing conditions (p < 0.05). The differences in pressure measures between the normally sighted and legally blind groups could be attributed mainly to the subgroup of subjects with acquired impairment. Our findings suggest that subjects with visual impairment present increased metatarsal pressures (i.e. forefoot), not yet associated to anterior displacement of COP or impaired balance control.

Balance, gait, and navigation performance are related to physical exercise in blind and visually impaired children and adolescents

Self-motion perception used for locomotion and navigation requires the integration of visual, vestibular, and proprioceptive input. In the absence of vision, postural stability and locomotor tasks become more difficult. Previous research has suggested that in visually deprived children, postural stability and levels of physical activity are overall lower than in sighted controls. Here we hypothesized that visually impaired and blind children and adolescents differ from sighted controls in postural stability and gait parameters, and that physically active individuals outperform sedentary peers in postural stability and gait parameters as well as in navigation performance. Fourteen blind and visually impaired children and adolescents (8-18 years of age) and 14 matched sighted individuals took part. Assessments included postural sway, single-leg stance time, parameters of gait variability and stability, self-reported physical activity, and navigation performance. Postural sway was larger and single-leg stance time was lower in blind and visually impaired participants than in blindfolded sighted individuals. Physical activity was higher in the sighted group. No differences between the group of blind and visually impaired and blindfolded sighted participants were observed for gait parameters and navigation performance. Higher levels of physical activity were related to lower postural sway, longer single-leg stance time, higher gait stability, and superior navigation performance in blind and visually impaired participants. The present data suggest that physical activity may enhance postural stability and gait parameters, and thereby promote navigation performance in blind and visually impaired children and adolescents.

The acute effects of two different rigid taping methods in patients with hallux valgus deformity

BACKGROUND

Hallux valgus (HV) is one of the most common deformities of the foot, and it causes great difficulties for the patients.

OBJECTIVE

We aimed to investigate the effects of different rigid taping techniques on HV angle, foot motor performance, balance and walking parameters.

METHODS

Twenty-two voluntary individuals (12 males, 10 females) with flexible HV deformities between 18 and 35 years of age were included in the study. All measurements were done before and after placebo, athletic and Mulligan tapings were applied. After a three-day interval, new taping was applied on the same subject. HV angle was measured by goniometer. Foot motor performance (single leg heel rise test), balance (unilateral stance, limits of stability, sensory integration of balance) and temporospatial parameters of gait (step length, stride length, step width, foot angle and cadence) were evaluated.

RESULTS

HV angles were reduced in all taping groups (p< 0.05). The Mulligan taping method was the most effective method in reducing HV angle. Foot motor performance was not affected by any type of taping (p> 0.05). Athletic taping increased step length and step width but reduced foot angle and cadence. The Mulligan taping increased cadence and reduced foot angle (p< 0.01). Both taping methods did not affect the postural stability and fall risk (p> 0.05). Stability limits were increased in Mulligan taping group (p< 0.05).

CONCLUSION

It can be concluded that Mulligan taping method may be an alternative treatment method for HV rehabilitation especially as it increased the limits of stability and maintaining the balance. Mulligan method is more effective than athletic taping in terms of reducing instant HV angle.

Physical, physiological and psychological profiles of elite Turkish taekwondo athletes

Study aim: To identify the physical, physiological and psychological profiles of elite Turkish taekwondo athletes.

Material and methods: Twelve players of the Turkish national taekwondo team (age = 22.7 ± 2.8 years, BMI = 22.2 ± 1.4 kg/m2, body fat = 12.8 ± 3.4%) participated in the study. Anthropometric measurements including leg length and foot size were assessed. Maximal oxygen uptake, explosive power of leg extensors, isokinetic peak torque, muscular endurance, anaerobic power, agility, flexibility, maximal speed, reaction time, and postural balance were examined by incremental treadmill running, vertical jump, isokinetic strength, sit-ups and push-ups, Wingate, shuttle run, sit-and-reach, 30-meter sprint, multiple-choice reaction time, and General Postural Stability and Athlete Single Leg stability tests, respectively. Psychological characteristics including mental skills and mood states were evaluated using OMSAT-3 and POMS tests.

Results: VO2max, isokinetic peak torque and Wingate test mean power values were 54.1 ± 4.4 mL ∙ kg−1 ∙ min−1, 191.7 ± 19.2 N ∙ m, and 9 ± 0.7 W/kg, respectively. Postural stability index 0.18 ± 0.06, single leg stability index 0.82 ± 0.11, reaction time 0.344 ± 0.032 s, 10 × 5-m shuttle run 17.09 ± 0.68 s, 30-meter sprint 4.60 ± 0.23 s, and vertical jump 43.5 ± 6.1 cm were the other values reported. The highest scores for the 12 mental skills in OMSAT-3 were for goal setting (6.25 ± 0.45) and self-confidence (6.16 ± 0.45). The lowest score was for Imagery (5.64 ± 0.36). The results of six mood states of POMS showed higher scores on the Vigor-activity, Anger-Hostility and Tension-Anxiety scales and lower scores on Depression-Dejection, Fatigue-Inertia and Confusion-Bewilderment than norms.

Conclusions: The findings of this study revealed the physical, physiological, and psychological characteristics in taekwondo. The results of the tests could be useful for performance assessment of taekwondo players.

Injuries and Illness Prevalence Prior to Competition in Goalball Players

Introduction:

Goalball is a sport specifically created for persons with visual impairments. In spite of all benefits that participating in sport-related activities brings to athletes with visual impairments, there is also the inherent, associated risk of being injured. Competing presenting injuries or illnesses or both not only decrease performance in contests but also increase the risk of acquiring new injuries. There is no information available regarding prior-to-competition injuries or illnesses in athletes with visual impairments. The objective of this research is to determine prevalence of injuries and diseases in athletes prior to a sport-competitive event.

Method:

A cross-sectional and descriptive study was conducted in 39 athletes (12 women; 41.02 ± 14.96 years old [15.4–71.5]) of Southern Chilean teams participating in the Goalball National Championship. Seven questions from a questionnaire about injuries and illnesses during 4 weeks prior to the competition were analyzed through frequency distribution and measures of key trends.

Results:

The prevalence of prior injuries was determined as 64.1% ( n = 25), which influenced training in different ways. Sixty percentage of athletes thought these injuries would affect their performance during the championship. Finally, 25.64% ( n = 10) reported having a disease.

Conclusions:

To our knowledge, this is the first study determining past injuries and illnesses in athletes with visual impairments. This information is important to elaborate preventive strategies and to provide better medical support during competitions.

Implications for practitioners:

The multidisciplinary teams preparing athletes with visual impairments can use this information to develop preventive strategies to reduce injuries, improve sport performance, and provide better medical support during competitions.

Improved balance performance accompanied by structural plasticity in blind adults after training

Postural control requires the sensory integration of visual, vestibular, and proprioceptive signals. In the absence of vision, either by blindfolding or in blind individuals, balance performance is typically poorer than with sight. Previous research has suggested that despite showing compensatory vestibular and proprioceptive processing during upright standing, balance performance in blind individuals is overall lower than in sighted controls with eyes open. The present study tested whether balance training, which places demands on vestibular and proprioceptive self-motion perception, improves balance performance in blind adults, and whether we find similar structural correlates in cortical and subcortical brain areas as have been reported in sighted individuals. Fourteen congenitally or late blind adults were randomly assigned to either a balance or a relaxation group and exercised twice a week for 12 weeks. Assessments prior to and after training included balance tests and the acquisition of T1-weighted MRI images. The blind balance group significantly improved in dynamic, static, and functional balance performance compared to the blind relaxation group. The balance performance improvement did not differ from that of age- and gender matched sighted adults after balance training. Cortical thickness increased in the left parahippocampus and decreased in the inferior insula bilaterally in the blind balance group compared to the blind relaxation group. Thickness decreases in the insula were related to improved static and functional balance. Gray matter volume was reduced in the left hippocampus proper and increased in the right subiculum in the blind balance group. The present data suggest that impaired balance performance in blind adults can be significantly improved by a training inducing plasticity in brain regions associated with vestibular and proprioceptive self-motion processing.

Do the center of mass strategies change with restricted vision during the sit-to-stand task?

BACKGROUND

The relationship between the visual sensory and center-of-mass characteristics during the sit-to-stand task is not well documented. Do the center of mass strategies change with restricted vision during the sit-to-stand task?

METHODS

The participants in this study were fifteen girls with congenital blindness (age (94.6 (5.6) months), mass (25.6 (2.0) kg), and height (1.3 (0.0) m)) and 30 healthy girls with no visual impairment who were divided randomly into two groups. The two experimental condition groups consisted of one in which the participants were assigned to keep their eyes open (age (95.8 (5.4) months), by mass (26.1 (5.1) kg), and by height (1.3 (0.0) m)) and the other in which the participants were assigned to keep their eyes closed (age (93.8 (0.0) months), by mass (24.2 (0.0) kg), and by height (1.1 (0.0) m)) for 20 min before the test. The center-of-mass displacement of the foot, leg, and thigh were calculated for dominance and non-dominance during the sit-to-stand performance at initiation, seat-off, and end events.

FINDINGS

Congenital blindness was associated with the non-dominant center-of-mass displacement of the foot increasing upwards during all events (initiation, p = 0.025; seat-off, p = 0.036; end, p = 0.034), as well the non-dominant center of mass of the foot moving anteriorly during the initiation point (p = 0.016). In addition, the center-of-mass displacements for the dominant and non-dominant feet (initiation, p = 0.006, and p = 0.016; seat-off, p = 0.006, and p = 0.014; end, p = 0.006, and p = 0.013, respectively) and legs (16.98%, p = 0.024, d = 0.95; and 17.88%, p = 0.032, d = 0.99, respectively) in the eyes-closed group shifted to a forward direction, and the center of mass of the non-dominant foot (initiation, p = 0.024; seat-off, p = 0.021; end, p = 0.012) moved significantly upwards. Furthermore, the whole body center of the mass velocity (anterior-posterior axis (initiation, p = 0.042; seat-off, p = 0.006; end, p = 0.005)) in the eyes-closed group was smaller than that in the eyes-open group.

INTERPRETATION

The findings show that the sit-to-stand center of the mass components in blind children may have clinical importance for the rehabilitation of these subjects.

Relationships between Different Field Test Performance Measures in Elite Goalball Players

Goalball is a Paralympic sport involving people with visual impairment. Little is known about the physical fitness of elite players of this sport, as previous studies only evaluated body composition and aerobic capacity. Thus, the aim of this study was to describe the performance of elite goalball players in different physical tests and to look for relationships between them. Eleven elite Brazilian goalball players, seven males and four females, were evaluated for body composition, maximal handgrip isometric force (MHGF), countermovement jump (CMJ), throwing velocity (TV) and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Players produced 41.54 ± 8.41 kgf in MHGF, 34.81 ± 7.2 cm in CMJ, 14.21 ± 1.89 m∙s⁻¹ in TV, and 505 ± 313 m in Yo-Yo IR1, with an estimated maximum oxygen consumption (VO₂max) of 40.64 ± 2.63 mL∙kg⁻¹∙min⁻¹. Most performance tests exhibited moderate to high correlations among them, while the percentage of body fat correlated with both the CMJ and Yo-Yo IR1 results. The current study reveals that CMJ could be a valuable monitoring tool as it was correlated with all other performance tests. The highest correlation observed was with TV (r = 0.754; p < 0.05), which is a key capacity in goalball. Moreover, high levels of body fat could be detrimental to anaerobic performance.

Gait and functionality of individuals with visual impairment who participate in sports

BACKGROUND

Individuals with visual impairment (VI) have often been observed to walk slower than individuals with unimpaired vision. These observations might be confounded by typical low levels of physical activity and greater sedentary behavior in individuals with VI than the overall population.

RESEARCH QUESTION

Here, we compared gait and balance measures between individuals with VI who participate in disability sports, and activity level matched sighted individuals.

METHODS

We assessed static balance, anthropometry, self-selected walking speed, locomotion rehabilitation index, and lower limb muscular endurance; and applied physical activity level and fear of falling questionnaires.

RESULTS

Individuals with VI who participate in disability sports, self-selected a similar walking speed (1.29 ± 0.26 m/s) as active sighted individuals (1.39 ± 0.21 m/s). Locomotor rehabilitation index and muscular endurance of lower limbs were also similar between groups. Individuals with VI presented lower static balance (42.0 ± 17.0s) than the sighted control group (45.0 ± 0s) when the controls were tested with their eyes open. However, no difference was found when the controls were tested with their eyes closed (30.3 ± 17.0s). Furthermore, individuals with VI showed a greater fear of falling.

SIGNIFICANCE

In conclusion, individuals with VI who participate in disability sports, as goalball and football, walk with similar self-selected walking speeds as active sighted individuals, but have slightly worse static balance and fear of falling.

Time-motion analysis of goalball players in attacks: differences of the player positions and the throwing techniques. Sports Biomech 2018;18:470-481. [PMID: 29578380 DOI: 10.1080/14763141.2018.1433871]

In this study, we aimed to analyse goalball players time-motion variables (distance covered, time spent, maximum and average velocities) in official goalball match attacks, taking into account the attack phases (preparation and throwing), player position (centres and wings) and throwing techniques (frontal, spin and between the legs). A total of 365 attacks were assessed using a video based method (2D) through manual tracking using the Dvideo system. Inferential non-parametric statistics were applied for comparison of preparation vs. throwing phase, wings vs. centres and, among the throwing techniques, frontal, spin and between the legs. Significant differences were found between the attack preparation versus the throwing phase for all player time-motion variables: distance covered, time spent, maximum player velocity and average player velocity. Wing players performed most of the throws (85%) and covered longer distances than centres (1.65 vs 0.31 m). The between the legs and the spin throwing techniques presented greater values for most of the time-motion variables (distance covered, time spent and maximum player velocity) than did the frontal technique in both attack phases. These findings provide important information regarding players' movement patterns during goalball matches that can be used to plan more effective training.

Postural control in blind individuals: A systematic review

Postural control (PC) requires the interaction of the three sensory systems for a good maintenance of the balance, and in blind people, lack of visual input can harm your PC. Thus the objective is to perform a literature review concerning role of sight in the maintenance of PC and the adaptation of brain structures when vision is absent. Studies were searched from Pubmed, and EMBASE that included individuals with congenital blindness. Articles studying person with acquired blindness or low vision was excluded from this review. 26 out of 322 articles were selected for review, and we found that 1) blind individuals exhibit PC deficits and that is compensated by the intensification of the remaining systems; 2) Neuroplastic adaptation occurs throughout the entire cerebral cortex; and 3) Sensorimotor stimulation and transcranial direct current stimulation seem to be a rehabilitation strategy. According to this review, the findings suggest that improved remaining sensations in the presence of adaptations and neuroplasticity, does not translate into better postural control performance. Regarding rehabilitation strategies, more studies are needed to show which therapeutic modality best contributes to postural control.

Postural deformities: potential morbidities to cause balance problems in patients with ankylosing spondylitis?

OBJECTIVE

This study aimed to assess the impact of postural deformities caused by ankylosing spondylitis (AS) on balance problems.

MATERIAL AND METHODS

This study included 29 patients with AS and 21 healthy controls. For assessing exercise capacity and dynamic balance, timed up and go test, five times sit-to-stand test, gait speed, and 6-min walk test were performed. Romberg tests were used to evaluate static balance and proprioception, whereas Dynamic Gait Index (DGI), Functional Gait Assessment (FGA), Berg Balance Scale (BBS), Activity Specific Balance Confidence Scale (ABC), Dizziness Handicap Inventory (DHI), and functional reach test were used to assess dynamic balance and the risk of falling. Using Bath Ankylosing Spondylitis Metrology Index (BASMI) scores, patients with AS were divided into two groups: those with scores 0-4 were assigned to subgroup AS1, and those with scores 5-10 were assigned to subgroup AS2.

RESULTS

In the whole group of patients with AS, five times sit-to-stand test, tandem Romberg test with eyes closed, and BBS and ABC scores were significantly worse than the healthy controls (p<0.05). In the AS2 subgroup having more severe and advanced disease, five additional parameters, including timed up and go test, 6-min walk test, functional reach test, FGA, and DHI scores were also significantly worse than the healthy controls (p<0.05). Comparing the two subgroups with each other, only BBS scores were significantly worse in the AS2 subgroup than in the AS1 subgroup.

CONCLUSION

Although in clinical practice, poor balance is not a common problem in AS, possibly because of compensatory mechanisms, patients with AS have poorer static and dynamic balance than healthy subjects. Significantly worse BBS scores in the AS2 subgroup than in the AS1 subgroup may suggest the presence of more dynamic balance problems in advanced disease; however, future studies comprising larger samples are necessary to confirm this assumption.

Game Performance Evaluation in Male Goalball Players

Goalball is a Paralympic sport exclusively for athletes who are visually impaired and blind. The aims of this study were twofold: to describe game performance of elite male goalball players based upon the degree of visual impairment, and to determine if game performance was related to anthropometric characteristics of elite male goalball players. The study sample consisted of 44 male goalball athletes. A total of 38 games were recorded during the Summer Paralympic Games in London 2012. Observations were reported using the Game Efficiency Sheet for Goalball. Additional anthropometric measurements included body mass (kg), body height (cm), the arm span (cm) and length of the body in the defensive position (cm). The results differentiating both groups showed that the players with total blindness obtained higher means than the players with visual impairment for game indicators such as the sum of defense (p = 0.03) and the sum of good defense (p = 0.04). The players with visual impairment obtained higher results than those with total blindness for attack efficiency (p = 0.04), the sum of penalty defenses (p = 0.01), and fouls (p = 0.01). The study showed that athletes with blindness demonstrated higher game performance in defence. However, athletes with visual impairment presented higher efficiency in offensive actions. The analyses confirmed that body mass, body height, the arm span and length of the body in the defensive position did not differentiate players’ performance at the elite level.

The Impact of a Vestibular-Stimulating Exercise Regime on Postural Stability in People with Visual Impairment

The aim of the study was to assess the impact of a vestibular-stimulating exercise regime on postural stability in individuals with visual impairment. The study group consisted of 70 people, including 28 persons (15 female and 13 male) with visual impairment and 42 (21 female and 21 male) without visual impairment. Each individual in the group with visual impairment was medically qualified for a 3-month training program. The research methodology included medical examination, anthropometric tests, and stabilometry tests on a Biodex Balance System SD (BBS). The tests were conducted twice: once before the start of training and again after 3 months of rehabilitation. The group with visual impairment showed significantly worse postural stability results than the control group for most of the stability parameters evaluated (OSI, APSI, and MLSI). Differences were noted between the groups with and without visual impairment for dynamic tests in women and for static tests in men. After training, the two groups showed roughly similar results for the stabilometry test with eyes closed. We conclude that exercises stimulating the vestibular system with head and body movements should be recommended for individuals with visual impairments to achieve better balance retention.

[Influence of anterior cruciate reconstruction on postural stability: A pre- and postoperative comparison]

BACKGROUND

Ruptures of the anterior cruciate ligament (ACL) lead to an anteromedial rotational instability in the knee joint and, thus, to a deterioration of the patient's ability to stand (postural control). It still remains unclear whether postural control can be restored by ACL reconstruction. The aim of this study was to investigate the effect of a unilateral ACL graft on the ability to stably stand on the injured leg using computer-aided dynamic posturography (CDP); the stability indices on standing on one leg were compared pre- and postoperatively.

PATIENTS AND METHODS

A total of 25 patients were studied after unilateral ACL injury and subsequent ACL reconstruction using CDP. The average time of follow-up was 608 days (range 357-821 days). The ability to stably stand on the healthy and injured leg was compared and evaluated for significant differences.

RESULTS

There was a significant improvement of postural control after ACL reconstruction. The Overall Stability Index (OSI) for the leg with ACL rupture was 3.7° ± 1.6° preoperatively and 3.0° ± 1.1° postoperatively (p < 0.05). In the postoperative comparison with the healthy leg, the value in the operated leg was 3.0° ± 1.1° and the healthy leg was 3.0° ± 1.4° (p = 0.99).

CONCLUSIONS

ACL replacement can be improve stability compared to the preoperative value by about 21% and even the stability level of the contralateral healthy knee can be achieved.

Influence of Visual Impairment Level on the Regulatory Mechanism Used during the Approach Phase of a Long Jump

The purpose of the study was to investigate the occurrence of stride regulation at the approach phase of the long jump in athletes with normal vision and visually deprived Class F12 and F13 athletes. All the athletes exhibited the presence of a regulatory mechanism. In the normal vision group this occurred on the fifth-to-last stride. In Class F12 athletes regulation commenced on the fourth-to-last stride for males and third-to-last stride for females. Class F13 males commenced regulation, like the control group, on the fifth-to-last stride; but females commenced on the fourth-to-last stride. The study demonstrated that reduced vision does not prevent Class F12 and F13 athletes from applying a regulatory mechanism similar to that observed in sighted athletes. However, the control mechanism of regulation emerged earlier in non-visually deprived long jumpers and the least visually impaired Class F13 athletes, signifying the importance of visual function in the regulatory stimuli.

Static and dynamic postural control in low-vision and normal-vision adults

OBJECTIVE

This study aimed to evaluate the influence of reduced visual information on postural control by comparing low-vision and normal-vision adults in static and dynamic conditions.

METHODS

Twenty-five low-vision subjects and twenty-five normal sighted adults were evaluated for static and dynamic balance using four protocols: 1) the Modified Clinical Test of Sensory Interaction on Balance on firm and foam surfaces with eyes opened and closed; 2) Unilateral Stance with eyes opened and closed; 3) Tandem Walk; and 4) Step Up/Over.

RESULTS

The results showed that the low-vision group presented greater body sway compared with the normal vision during balance on a foam surface (p≤0.001), the Unilateral Stance test for both limbs (p≤0.001), and the Tandem Walk test. The low-vision group showed greater step width (p≤0.001) and slower gait speed (p≤0.004). In the Step Up/Over task, low-vision participants were more cautious in stepping up (right p≤0.005 and left p≤0.009) and in executing the movement (p≤0.001).

CONCLUSION

These findings suggest that visual feedback is crucial for determining balance, especially for dynamic tasks and on foam surfaces. Low-vision individuals had worse postural stability than normal-vision adults in terms of dynamic tests and balance on foam surfaces.

Functional balance assessment with pediatric balance scale in girls with visual impairment

PURPOSE

To examine functional balance abilities in girls with visual impairment (VI) and to investigate the correlation between stabilography and clinical balance assessment using the Pediatric Balance Scale (PBS) in girls with VI.

METHODS

The PBS and stabilography were administered to 26 girls with VI aged 10 to 15 years. The association between PBS scores and sway parameters was examined using the Spearman correlation coefficient.

RESULTS

The range of PBS scores was 47 to 56. Balance difficulties appeared in single-leg stance, tandem stance, and reaching forward. The PBS scores correlated with all but 2 sway parameters, with r values ranging from -0.18 to -0.58.

CONCLUSIONS

Girls with VI present difficulties in upright stance when the size of the base of support is narrowed and in situations where the center of gravity approaches the edge of the base of support. There is a need to provide interventions to improve balance abilities in girls with VI.

Effects of knee bracing on postural control after anterior cruciate ligament rupture

STUDY DESIGN

Randomized clinical trial.

OBJECTIVES

To investigate the effects of functional knee braces on postural control in patients with anterior cruciate ligament (ACL) rupture.

BACKGROUND

ACL rupture leads to both mechanical knee instability and deficits in proprioception. Although elastic knee braces do not increase mechanical stability, patients report improved stability when wearing a brace. Elastic braces were found to reduce the loss of proprioception. It is, however, still unclear whether they also improve postural control, which involves the processing of proprioceptive input at a higher level.

METHODS

We studied 58 patients with isolated unilateral ACL rupture using computerized dynamic posturography and compared overall stability index (OSI) scores for injured and uninjured legs with and without a knee brace. In addition, patients were classified as copers and non-copers depending on knee function.

RESULTS

Within subjects, OSI scores were 3.0 ± 1.1° for uninjured legs when unbraced, 2.8±1.3° for uninjured legs when braced (p=0.17), 3.7 ± 1.5° for unbraced injured legs, and 2.9 ± 1.3° for braced injured legs (p<0.001). For the injured legs of copers and non-copers, OSI scores were 3.4° ± 1.2° for copers and 4.0° ± 1.6° for non-copers in the unbraced condition (p=0.11) and 2.7 ± 1.0° for copers and 3.1 ± 1.4° for non-copers in the braced condition (p=0.26).

CONCLUSION

Elastic knee braces increase postural stability by approximately 22% in patients with ACL rupture. There was no difference in postural stability between uninjured and injured legs in the braced condition. One possible explanation is that bracing improves both proprioception and postural control.

Comparison of manual balance and balance board tests in healthy adults

Objective

To investigate the correlations of scores on the Timed Up and Go (TUG) test and the Single Leg Stance (SLS) test with stability scores on the Biodex Balance System (BBS) in healthy adults.

Method

The postural balance of 73 participants was measured on the TUG and SLS tests and with the Overall Stability Index (OSI) on the BBS. The participants were divided into groups by age and by times on the TUG and SLS. The correlations between TUG or SLS and OSI scores were analyzed by groups.

Results

TUG scores were significantly correlated with OSI scores in age under 65 years, TUG over 10 seconds and SLS over 30 seconds groups (level 12). TUG scores were also correlated with OSI in total (level 10) and TUG under 10 seconds groups (level 2). However, there were no significant relationships between SLS and OSI scores.

Conclusion

OSI scores on the BBS are significantly correlated with TUG scores, especially at the easy levels. According to the findings of present study, relatively easy BBS levels are considered to assess the postural balance in healthy adults.

Evaluating the Approach Run of Class F11 Visually Impaired Athletes in Triple and Long Jumps

The present study examined stride pattern characteristics of Class F11 visually impaired long jumpers and triple jumpers. Athletes demonstrated initial ascending footfall variability followed by descending variability, on the second (long jumpers) and third (triple jumpers) stride prior to take-off, at a mean distance of 6.26 m (long jumpers) and 7.36 m (triple jumpers) from the take-off board. Toe-board-distance variability reached a maximum value of 0.36 m and 0.38 m for the long and triple jump, respectively. Last stride toe-board-distance variability was 0.29 m (long jump) and 0.25 m (triple jump). Class F11 visually impaired athletes exhibit regulation of goal-directed gait analogous to that of non-visually impaired athletes.

Static balance control and lower limb strength in blind and sighted women

The aim of the present study was to examine isokinetic and isometric strength of the knee and ankle muscles and to compare center of pressure (CoP) sway between blind and sighted women. A total of 20 women volunteered to participate in this study. Ten severe blind women (age 33.5 +/- 7.9 years; height 163 +/- 5 cm; mass 64.5 +/- 12.2 kg) and 10 women with normal vision (age 33.5 +/- 8.3 years; height 164 +/- 6 cm; mass 61.9 +/- 14.5 kg) performed 3 different tasks of increasing difficulty: Normal Quiet Stance (1 min), Tandem Stance (20 s), and One-Leg Stance (10 s). Participants stood barefoot on two adjacent force platforms and the CoP variations [peak-to-peak amplitude (CoPmax) and SD of the CoP displacement (CoPsd)] were analyzed. Sighted participants performed the tests in eyes open and eyes closed conditions. Torque/angular velocity and torque/angular position relationships were also established using a Cybex dynamometer for knee extensors and flexors as well as for ankle plantar and dorsiflexors. The main finding of this study was that the ability to control balance in both anterior/posterior and medio/lateral directions was inferior in blind than in sighted women. However, when sighted participants performed the tests blindfolded, their CoP sway increased significantly in both directions. There were no differences in most isometric and concentric strength measurements of the lower limb muscles between the blind and sighted individuals. Our results demonstrate that vision is a more prominent indicator of performance during the postural tasks compared to strength of the lower limbs. Despite similar level of strength, blind individuals performed significantly worse in all balance tests compared to sighted individuals.

Physical Fitness of Visually Impaired Adolescent Goalball Players

This study compared the physical fitness of 28 visually impaired goalball players ( M = 13 yr.) and a group of 27 less active age-matched adolescents. Physical characteristics (age, height, weight, sex) and visual acuity of the children were recorded. Body composition (Body Mass Index, skinfold thickness of triceps plus calf), musculoskeletal function (trunk-lift, curl-up, isometric push-up, shoulder-stretch tests) and aerobic function (1-mile run/walk test) were evaluated according to the Brockport Physical Fitness Test Battery. Also, anaerobic power was assessed by a vertical jump test. Physical fitness of visually impaired goalball players was higher than that of the more sedentary group (p<.05), except shoulder-stretch test values (p>.05). It was considered that directing visually impaired children to participation sports or recreational activities such as goalball has importance in improving their physical fitness.