Body weight is a strong predictor of postural stability

The influence of peripheral neuropathy, gender, and obesity on the postural stability of patients with type 2 diabetes mellitus

AIM

To assess the influence of peripheral neuropathy, gender, and obesity on the postural stability of patients with type 2 diabetes mellitus.

METHODS

151 patients with no history of otology, neurology, or orthopaedic or balance disorders accepted to participate in the study. After a clinical interview and neuropathy assessment, postural stability was evaluated by static posturography (eyes open/closed on hard/soft surface) and the "Up & Go" test.

RESULTS

During static posturography, on hard surface, the length of sway was related to peripheral neuropathy, gender, age, and obesity; on soft surface, the length of sway was related to peripheral neuropathy, gender, and age, the influence of neuropathy was larger in males than in females, and closing the eyes increased further the difference between genders. The mean time to perform the "Up & Go" test was 11.6 ± 2.2 sec, with influence of peripheral neuropathy, gender, and age.

CONCLUSION

In order to preserve the control of static upright posture during conditions with deficient sensory input, male patients with type 2 diabetes mellitus with no history of balance disorders may be more vulnerable than females, and obesity may decrease the static postural control in both males and females.

Theoretical and experimental indicators of falls during pregnancy as assessed by postural perturbations

Throughout pregnancy, women experience physical, physiological, and hormonal alterations that are often accompanied by decreased postural control. According to one study, nearly 27% of pregnant women fell while pregnant. This study had two objectives: (1) to characterize the postural responses of pregnant fallers, nonfallers, and controls to surface perturbations, and (2) to develop a mathematical model to gain insights into the postural control strategies of each group. This retrospective analysis used experimental data obtained from 15 women with a fall history during pregnancy, 14 women without a fall history during pregnancy, and 40 nonpregnant controls. Small, medium, and large translational support surface perturbations in the anterior and posterior directions were performed during the pregnant participants' second and third trimesters. A two-segmented mathematical model of bipedal stance was developed and parameterized, and optimization tools were used to identify ankle and hip stiffness, viscosity, and the feedback time delay by searching for the best fits to experimental COP data. The peak differences between the center of pressure and center of gravity (COP-COG) values were significantly smaller for the pregnant fallers compared with the pregnant nonfallers and controls (p<0.01). Perturbation magnitude was a significant factor (p<0.01), but perturbation direction was not (p=0.24). Model fits were obtained with a mean goodness of fit value of R(2)=0.92. Theoretical results indicated that pregnant nonfallers had higher ankle stiffness compared with the pregnant fallers and the controls, which suggests that ankle stiffness itself may be the dominant reason for the different dynamic response characteristics (e.g., peak COP-COG) observed. We conclude that increasing ankle stiffness could be an important strategy to prevent falling by pregnant women.

Fine and gross motor skills differ between healthy-weight and obese children

Within the obesity literature, focus is put on the link between weight status and gross motor skills. However, research on fine motor skills in the obese (OB) childhood population is limited. Therefore, the present study focused on possible weight related differences in gross as well as fine motor skill tasks. Thirty-four OB children (12 ♀ and 22 ♂, aged 7-13 years) were recruited prior to participating in a multidisciplinary treatment program at the Zeepreventorium (De Haan, Belgium). Additionally, a control group of 34 age and gender-matched healthy-weight (HW) children was included in the study. Anthropometric measures were recorded and gross and fine motor skills were assessed using the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2). Results were analyzed by independent samples t-tests, multivariate analysis of variance, and a chi-squared test. Being OB was detrimental for all subtests evaluating gross motor skill performance (i.e., upper-limb coordination, bilateral coordination, balance, running speed and agility, and strength). Furthermore, OB children performed worse in fine motor precision and a manual dexterity task, when compared to their HW peers. No group differences existed for the fine motor integration task. Our study provides evidence that lower motor competence in OB children is not limited to gross motor skills alone; OB children are also affected by fine motor skill problems. Further investigation is warranted to provide possible explanations for these differences. It is tentatively suggested that OB children experience difficulties with the integration and processing of sensory information. Future research is needed to explore whether this assumption is correct and what the underlying mechanism(s) could be.

Plantar pressure patterns in women affected by Ehlers-Danlos syndrome while standing and walking

This study aims to quantitatively characterize plantar pressure distribution in women affected by Ehlers-Danlos syndrome of the hypermobile type (EDS-HT) to verify the existence of peculiar patterns possibly related to postural anomalies or physical and functional lower limb impairments typical of this disease. A sample of 26 women affected by EDS-HT (mean age 36.8, SD 12.0) was tested using a pressure platform in two conditions, namely static standing and walking. Raw data were processed to assess contact area and mean and peak pressure distribution in rearfoot, midfoot and forefoot. Collected data were then compared with those obtained from an equally numbered control group of unaffected women matched for age and anthropometric features. The results show that, in both tested conditions, women with EDS-HT exhibited significantly smaller forefoot contact areas and higher peak and mean pressure than the control group. No differences in the analyzed parameters were found between right and left limb. The findings of the present study suggest that individuals with EDS-HT are characterized by specific plantar pressure patterns that are likely to be caused by the morphologic and functional foot modification associated with the syndrome. The use of electronic pedobarography may provide physicians and rehabilitation therapists with information useful in monitoring the disease's progression and the effectiveness of orthotic treatments.

Body load and the postural precursors of motion sickness

Physical properties of the body affect the control of standing body sway. One example occurs when loads are added to the body, such as occurs when wearing a backpack. Other research has shown that subjective symptoms of motion sickness are preceded by differences in body sway between individuals who later report motion sickness and those who do not. In the present study we asked whether loads worn on the body would affect relations between body sway and motion sickness. We measured standing body sway without load and then with loads worn at the shoulders or thighs. Then participants were exposed to potentially nauseogenic visual motion stimulation while wearing shoulder or thigh loads. We measured body sway continuously during exposure to visual motion. Thirteen of 36 participants (36%) reported motion sickness. Body sway was affected by loads and by load position, consistent with previous research. Also consistent with previous research, sway differed between well and sick participants both before and during exposure to visual motion stimuli. In addition, during room motion the well and sick participants responded differently to loads. The results are consistent with the hypothesis that physical properties of the body can affect relations between body sway and motion sickness.

Balance ability and postural stability among patients with painful shoulder disorders and healthy controls

Background

In therapeutic settings, patients with shoulder pain often exhibit deficient coordinative abilities in their trunk and lower extremities. The aim of the study was to investigate 1) if there is a connection between shoulder pain and deficits in balance ability and postural stability, 2) if pain intensity is related to balance ability and postural stability, and 3) if there is a connection between body mass index (BMI) and balance ability and postural stability.

Methods

In this case–control study, patients (n = 40) with pathological shoulder pain (> 4 months) were matched with a healthy controls (n = 40) and were compared with regard to their balance ability and postural stability. Outcome parameters were postural stability, balance ability and symmetry index which were measured using the S3-Check system. In addition, the influence of shoulder pain intensity and BMI on the outcome parameters was analysed.

Results

Patients with shoulder pain showed significantly worse results in measurements of postural stability right/left (p < 0.01) and front/back (p < 0.01) as well as balance ability right/left (p = 0.01) and front/back (p < 0.01) compared to healthy controls. There were no significant group differences with regard to symmetry index. However, there was a significant (p < 0.01) symmetry shift towards the affected side within the shoulder pain group. There was no correlation between pain intensity and measurements of balance ability or postural stability. Likewise, no correlation between BMI and deficiencies in balance ability and postural stability was established.

Conclusions

Patients with pathological shoulder pain (> 4 months) have deficiencies in balance ability and postural stability; however the underlying mechanisms for this remain unclear. Neither pain intensity nor BMI influenced the outcome parameters. Patients with shoulder pain shift their weight to the affected side. Further research is needed to determine if balance training can improve rehabilitation results in patients with shoulder pathologies.

Adduction moment increases with age in healthy obese individuals

There is a need to understand how obesity and aging interact to cause an increased risk of medial knee osteoarthritis (OA). This study tested whether the knee adduction and flexion moments increase with age in healthy normal-weight and obese adults, as well as the mechanism of this increase. We analyzed whether ground reaction force magnitude, knee alignment, step width, toe-out angle, body volume distribution, and limb position (knee position relative to the pelvis center) are associated with the adduction moment and whether these variables also change with age. Ninety-six healthy volunteers (60 normal-weight and 36 obese) were tested using marker-based gait analysis; knee alignment was based on marker positions during quiet standing. Adduction moment increased with age in obese (R(2) = 0.19), but not in normal-weight individuals (R(2) = 0.01); knee flexion moment did not change with age in either group. In the obese, only knee alignment and limb position were related to the adduction moment (R(2) = 0.19 and 0.51), but only limb position changed with age (R(2) = 0.26). The resulting increase in adduction moment suggests greater medial compartment loads, which may combine with elevated levels of inflammation to contribute to the increased risk of medial OA in this population.

A comparative study of performance in simple and choice reaction time tasks between obese and healthy-weight children

This study investigated weight status related differences in executive functions and movement execution to determine whether or not childhood obesity is associated with impaired perceptual-motor function. Nineteen obese (OB) children (10 ♂ and 9 ♀, aged 6-12 years) and nineteen gender and age matched healthy-weight (HW) peers performed two computer-based reaction time tasks. For both the simple and four choice reaction time (SRT/CRT) task condition, absolute mean reaction time (RT) and movement time (MT) were determined and expressed as a percentage of total response time (RsT). During the SRT task, OB children were intrinsically slower than their HW peers as reflected by a significantly higher absolute RT, MT and RsT. In the CRT task, however, between-group differences were only present for RT and RsT, whereas absolute MT was comparable among OB and HW participants. As a result, the relative temporal structure of RsT significantly differed between BMI groups, with a greater RT percentage among the OB children. During the CRT condition, OB children probably await final decision-making with regard to the execution of their response movement, which then no longer needs to be adjusted. Our results therefore indicate the use of a more conservative strategy within the OB group, suggesting that childhood obesity is associated with impaired perceptual-motor function. Besides the widely accepted mechanical explanation, a better understanding of the mechanisms underlying OB children's motor incompetence is needed to set up appropriate interventions to tackle this deficit and indirectly address associated health-related problems.

Characteristics of Postural Sway during Quiet Standing Before and After the Occurrence of Neurogenic Intermittent Claudication in Female Patients with Degenerative Lumbar Spinal Canal Stenosis

[Purpose] This study investigated the effect of neurological symptoms and/or signs after the occurrence of neurogenic intermittent claudication (NC) on postural sway during quiet standing of patients with lumbar spinal canal stenosis (LSS). [Subjects and Methods] Thirty-two female patients with LSS at the L4/5 level were studied. We measured the path of center of foot pressure (COP) during quiet standing with eyes open for 30 s using a stabilometer before and after the occurrence of NC. [Results] The total path length of COP (LC) and area surrounded by the outline of the path of COP (AC) significantly increased after NC. Body mass index (BMI) correlated with both the NC rate (after NC/before NC) of LC and that of AC. The average lateral COP displacement from the center of the base of support (COPRL) before NC was located on the asymptomatic side from the center of the base of support in 29 of 32 patients. After NC, COPRL moved to the symptomatic side in 31 patients. [Conclusion] These results suggest that patients with LSS are at risk of falling after NC, especially those with high BMI.

The impact of obesity on balance control in community-dwelling older women

Older individuals have impaired balance control, particularly those that are frail and/or have sensory deprivations. Obese individuals show faster body sway during upright stance than normal weight individuals, suggesting that they also have difficulty controlling balance even if they do not have the same sensory issues as the older people. Therefore, the objective of this study was to examine if obesity is associated to a decreased balance control in older women. Postural sway of normal weight (n = 15, age = 70.8 ± 5.5 years; BMI = 22.2 ± 1.9 kg/m(2)), overweight (n = 15, age = 71.7 ± 4.3 years; BMI = 27.3 ± 1.3 kg/m(2)), and obese (n = 15, age = 71.1 ± 4.3 years; BMI = 33.1 ± 3.4 kg/m(2)) women was measured with a force platform for normal quiet stance lasting for 30 s in opened and closed eyes conditions. The obese group oscillated at a faster speed than the normal weight group (vision 0.99 ± 0.29 cm/s vs. 0.70 ± 0.16 cm/s, p < 0.01; no vision 1.43 ± 0.50 cm/s vs. 0.87 ± 0.23 cm/s, p < 0.01). The obese group exhibited greater range in both axes without vision compared to the normal weight group (p < 0.05). When observing sway density parameters, the obese group also spent less time in stability zones (2 mm radius area in which the center of pressure is relatively stable), and the distance between these stability zones are greater than the normal weight group in both visual conditions (p < 0.01 and p < 0.05, respectively). Obesity clearly affects postural control in older women. Our results suggest that obesity has a negative impact on the capacity of older woman to adequately use proprioceptive information for posture control. As postural instability or balance control deficits are identified as a risk factor for falling, our results also suggest that obesity in older women could be considered as another potential contributing factor for falling.

Obesity effect on a multimodal physiotherapy program for low back pain suffers: patient reported outcome

BACKGROUND

Several studies have linked obesity to the increased likelihood of lower back pain, but there are no studies focussing on the effectiveness of a multimodal physiotherapy programme (MPP) in obese subjects who suffer from chronic non-specific lower back pain (CNLBP). The aim of this study was to compare the effectiveness of an MPP in obese (G1) (body mass index (BMI):≥30) and non-obese (G2) (BMI:<30) patients with CNLBP.

METHODS

A quasi-experimental study with pre- and post-intervention evaluations of an MPP (lasting 8 weeks) was conducted on obese and non-obese patients with CNLBP. A total of 53 people were included in the study: G1, composed of 19 patients (10 men and 9 women) with a BMI of 33.75 and a mean age of 52.94 years, and G2, composed of 34 patients (18 men and 16 women) with a mean age of 49.19 years and an average BMI of 25.56. All patients were measured to calculate pre-intervention (baseline) and post-intervention (8 weeks) changes in disability (RMQ) and health related quality of life in physical and mental health component state of SF12 and quality of life (EQ-5D and EQ-VAS).

RESULTS

Post-intervention, non-obese group shown significant high improve than obese group in disability (RMQ: 4.00), physical component state of SF-12: (-7.26) and quality of life (EQ-VAS.: -10.49).

CONCLUSIONS

In patients with CNLBP, a BMI more than or equal to 30 minimises the effects of an MPP lasting 8 weeks.

Are there changes in postural regulation across the lifespan?

The purpose was to obtain parameters of postural regulation (n = 1724) of asymptomatic subjects (6-97 years). The maximum postural stability and capacity of postural subsystems were calculated for the age ranges from 34 to 35 years (men) and from 38 to 44 years (women). A significant decline in postural performance was observed in the 40s (men) and 50s (women). Data can be used in the evaluation of dizziness and balance disorders in people of all ages.

Origins of balance disorders during a daily living movement in obese: can biomechanical factors explain everything?

Obese people suffer from postural deficits and are more subject to falls than their lean counterpart. To improve prevention and post-fall rehabilitation programs, it seems important to better understand the posturo-kinetic disorders in daily life situations by determining the contribution of some key factors, mainly morphological characteristics and physical activity level, in the apparition of these disorders. Twelve severe android obese and eight healthy non obese adults performed a reaching task mobilizing the whole body. To further determine the origin of the postural and motor behavior differences, non obese individuals also performed an experimental session with additional constraints which simulated some of the obese morphological characteristics. Impact of the sedentary lifestyle was also studied by dissociation of the obese in two subgroups: physically « active » and physically « inactive ». Movement kinetics and kinematics were characterized with an optoelectronic system synchronized to a force platform. The mechanical equilibrium pattern was evaluated through the displacements of the Centre of Mass (CoM) and the centre of foot pressure within the Base of Support (BoS). Results showed that obesity decreased movement speed (≈-23%, p<0.01), strongly increased CoM displacement (≈+30%, p<0.05) and induced an important spatio-temporal desynchronization (≈+40%, p<0.05) of the focal and postural components of the movement during the transition between the descending and ascending movements. The role of some morphological characteristics and of physical activity on obese patients' postural control disorder is discussed and set back in the more general context of overall factors contributing to postural deficits with obesity.

Does postural sway change in association with manual therapeutic interventions? A review of the literature

STUDY DESIGN

Literature Review

OBJECTIVES

The objective of this literature review was to determine if postural sway changes in association with manual therapeutic interventions and to investigate whether any changes occur in healthy individuals or in association with pain intensity.

SUMMARY OF BACKGROUND DATA

Improving postural stability has been proposed as a goal of manual therapeutic interventions. So far, no literature review has addressed whether there is supportive evidence for this and if so, what factors may be associated or causative for observed sway alterations.

SEARCH METHODS

Seven online databases (PubMed, MEDLINE, EMBASE, CINAHL, Web of Science, ScienceDirect and the Cochrane library) were systematically searched followed by a manual search of the retrieved papers.

SELECTION CRITERIA

Studies comparing postural sway derived from bipedal force plate measurements in association with a manual therapeutic intervention, ideally compared to a control group.

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened titles and abstracts for relevance, conducted the data extraction and the risk of bias assessment which was conducted using the RTI item bank. A descriptive analysis was conducted as the heterogeneous study designs prevented pooling of data.

RESULTS

Nine studies of varying methodological quality met the inclusion criteria. No direct comparison of data across the studies was possible. There was no evidence that manual interventions lead to a change in postural sway in healthy individuals regardless of the body regions addressed by the intervention. There was some indication that postural sway may change at follow-up measurements in pain sufferers; however, this may be due to variations in pain intensity rather than resulting from the intervention itself.

CONCLUSIONS

There is no conclusive scientific evidence that manual therapeutic interventions may exhibit any immediate or long-term effect on COP excursions. Any changes in sway may be attributable to decreases in pain intensity.

The fractal dimension approach in posture: a comparison between Down and Prader-Willi syndrome patients

The suitability of new dynamic system analysis was investigated to compare postural control in Prader-Willi syndrome (PWS) and Down syndrome (DS) patients. Time-domain, frequency-domain parameters and fractal dimension (FD) of centre of pressure (CoP) were computed in maintaining normal standing on a force platform in 20 DS and 13 PWS patients, compared to 26 obese (obese control group, OCG) and 20 healthy individuals (healthy control group, HCG). DS and PWS showed greater displacements along both directions and longer sway path (SP) parameter than HCG and OCG, with statistical differences between PWS and DS for anteroposterior displacement and SP. DS used higher frequency strategy when compared to PWS, OCG and HCG. Both DS and PWS were characterised by greater values of FD than OCG and HCG, with higher values in DS. The analyses in frequency domain and of the dynamic nature of CoP suggest that DS patients are characterised by a more complex and irregular signal than PWS patients.

Relationship between anthropometric factors, gender, and balance under unstable conditions in young adults

The objective of this study was to evaluate the relationship between the anthropometric factors of height, body mass, body mass index and postural balance and to compare the balance indices between genders in the upright standing position, in healthy adult subjects under conditions of instability. Forty individuals were subjected to functional tests of body stability using the Biodex Balance System, and the resulting indices were correlated with body mass, height, and body mass index, and also compared between genders. Body mass was the main anthropometric factor that influenced variations in postural balance, with a high correlation between groups and with all variables. A linear regression analysis showed that body mass associated with BMI explained 66% of the overall stability, and body mass explained 59% of the anteroposterior stability index and 65% of the mediolateral stability index. In the female group, body mass explained 72% of the overall balance, 66% of the anteroposterior, and 76% of the medio-lateral stability index. Increased body mass requires greater movements to maintain postural balance. Height and BMI presented moderate correlations with balance. Women showed less movement than men on the Biodex Balance System.

Clinical measures are feasible and sensitive to assess balance and gait capacities in older persons with mild to moderate Intellectual Disabilities

Mobility limitations are common in persons with Intellectual Disabilities (ID). Differences in balance and gait capacities between persons with ID and controls have mainly been demonstrated by instrumented assessments (e.g. posturography and gait analysis), which require sophisticated and expensive equipment such as force plates or a 3D motion analysis system. Most physicians and allied healthcare professionals working with persons with ID do not have such equipment at their disposal, so they must rely on clinical tests to determine whether balance and gait are affected. The aim of this study was to investigate whether existing clinical balance and gait tests are feasible in older persons with mild to moderate ID and to examine whether these tests are able to show limitations in balance and gait capacities in the ID population compared to age-matched peers in the general population. Furthermore, it was aimed to identify the most important determinants of balance and gait disability in persons with the ID. A total of 76 older persons with mild to moderate ID (43 male, mean age 63.1 ± 7.6 years) and 20 healthy controls (14 male, mean age 62.2 ± 5.6 years) participated. Balance and gait abilities were assessed with the Berg Balance Scale (BBS), the Functional Reach test (FR), the Timed Up and Go Test (TUGT), the timed Single Leg Stance (SLS) and the Ten Metre Walking Test (TMWT). Our study showed that it is feasible to conduct standard clinical balance and gait tests in older persons with mild to moderate ID. Balance and gait performance of persons with ID is substantially worse compared to older persons of the general population. Age, number of co-morbidities, Body Mass Index (BMI), body sway and fear of falling are associated with balance and gait performance in persons with ID. These factors might help in the selection of subjects to be monitored on their balance and gait capacities.

The influence of anthropometric factors on postural balance: the relationship between body composition and posturographic measurements in young adults

OBJECTIVE

The aim of the present study was to evaluate the influence of anthropometric characteristics and gender on postural balance in adults. One hundred individuals were examined (50 males, 50 females; age range 20-40 years).

METHODS

The following body composition measurements were collected (using bone densitometry measurements): fat percentage (% fat), tissue (g), fat (g), lean mass (g), bone mineral content (g), and bone mineral density (g/cm²). In addition, the following anthropometric measurements were collected: body mass (kg), height (cm), length of the trunk-cephalic region (cm), length of the lower limbs (cm) and length of the upper limbs (cm). The following indices were calculated: body mass index (kg/m²), waist-hip ratio and the support base (cm²). Also, a postural balance test was performed using posturography variables with open and closed eyes.

RESULTS

The analysis revealed poor correlations between postural balance and the anthropometric variables. A multiple linear regression analysis demonstrated that the whole group (female and male) height explained 12% of the medial-lateral displacement, 10% of the speed of oscillation, and 11% of the displacement area. The length of the trunk-cephalic length explained 6% of the displacement in the anteroposterior direction. With eyes closed, the support base and height explained 18% of the medial displacement, and the lateral height explained 10% of the displacement speed and 5% of the scroll area.

CONCLUSION

Measured using posturography, the postural balance was only slightly influenced by the anthropometric variables, both with open and closed eyes. Height was the anthropometric variable that most influenced postural balance, both in the whole group and separately for each gender. Postural balance was more influenced by anthropometric factors in males than females.

Foot-ground interaction during upright standing in children with Down syndrome

This study aimed to quantitatively characterize the main foot-ground contact parameters during static upright standing and to assess foot evolution with increasing age in young individuals affected by Down syndrome (DS). To this end, 99 children with DS of mean age 9.7 (1.7) were tested using a pressure sensitive mat, and the raw data were processed to extract information about overall and rearfoot, midfoot and forefoot contact area, Arch Index (AI) and average contact pressure. The values obtained were then compared with those calculated from a sample of age- and gender-matched participants (control group, CG). Children with DS exhibited larger midfoot and reduced forefoot contact areas with respect to CG participants (+53% and -35% respectively, p<0.001), increased AI values (DS 0.31, CG 0.20, p<0.001) and increased average contact pressures in the midfoot and forefoot. The overall foot development for the two groups followed a similar trend, although in individuals with DS a curve that relates increases in midfoot contact area with age is characterized by a steeper gradient, and the forefoot contact area appeared systematically smaller regardless of age. The large prevalence of the flatfoot type in children with DS (which is known to be originated by hypotonia and ligamentous laxity) associated with the presence of higher average contact pressure in midfoot and forefoot justify the need for careful podiatric surveillance throughout childhood to reduce balance and gait impairment which are likely to affect untreated subjects when they reach adulthood.

Influência da obesidade e da força de preensão palmar no equilíbrio postural estático de idosas ativas

O objetivo deste estudo foi investigar a influência da obesidade e da força de preensão palmar (FPP) no equilíbrio postural estático de idosas ativas nas condições de olhos abertos e fechados. Participaram 31 idosas (16 eutróficas e 15 obesas). A idade média e o Índice de Massa Corpórea (IMC) das eutróficas foram, respectivamente, 68,3±2,7 anos e 23,4±1,6kg/m², e das obesas 69,1±2,7 anos e 33,5±3kg/m². A FPP foi avaliada usando um dinamômetro (JAMAR). O equilíbrio postural estático foi avaliado usando um sistema tridimensional nas condições de olhos abertos (OA) e fechados (OF), durante 90 segundos cada condição. A FPP das idosas eutróficas foi 25,1±4,6kgf e das obesas foi 24,8±5,2kgf, não havendo diferenças significativas. No equilíbrio postural, foram observadas diferenças significativas entre os grupos apenas no deslocamento máximo a-p com AO (p=0,04) e OF (p<0,01), com as idosas obesas apresentando menor deslocamento a-p em relação às eutróficas. Não houve correlação entre o deslocamento máximo a-p com IMC e a FPP. No presente estudo FPP não influenciou o equilíbrio postural estático, enquanto a obesidade foi fator determinante de menor deslocamento ântero-posterior de idosas ativas.

The health and cost implications of high body mass index in Australian defence force personnel

Background

Frequent illness and injury among workers with high body mass index (BMI) can raise the costs of employee healthcare and reduce workforce maintenance and productivity. These issues are particularly important in vocational settings such as the military, which require good physical health, regular attendance and teamwork to operate efficiently. The purpose of this study was to compare the incidence of injury and illness, absenteeism, productivity, healthcare usage and administrative outcomes among Australian Defence Force personnel with varying BMI.

Methods

Personnel were grouped into cohorts according to the following ranges for (BMI): normal (18.5 − 24.9 kg/m²; n = 197), overweight (25–29.9 kg/m²; n = 154) and obese (≥30 kg/m²) with restricted body fat (≤28% for females, ≤24% for males) (n = 148) and with no restriction on body fat (n = 180). Medical records for each individual were audited retrospectively to record the incidence of injury and illness, absenteeism, productivity, healthcare usage (i.e., consultation with medical specialists, hospital stays, medical investigations, prescriptions) and administrative outcomes (e.g., discharge from service) over one year. These data were then grouped and compared between the cohorts.

Results

The prevalence of injury and illness, cost of medical specialist consultations and cost of medical scans were all higher (p < 0.05) in both obese cohorts compared with the normal cohort. The estimated productivity losses from restricted work days were also higher (p < 0.05) in the obese cohort with no restriction on body fat compared with the normal cohort. Within the obese cohort, the prevalence of injury and illness, healthcare usage and productivity were not significantly greater in the obese cohort with no restriction on body fat compared with the cohort with restricted body fat. The number of restricted work days, the rate of re-classification of Medical Employment Classification and the rate of discharge from service were similar between all four cohorts.

Conclusions

High BMI in the military increases healthcare usage, but does not disrupt workforce maintenance. The greater prevalence of injury and illness, greater healthcare usage and lower productivity in obese Australian Defence Force personnel is not related to higher levels of body fat.

Unstable shoes increase energy expenditure of obese patients

BACKGROUND

Ergonomic unstable shoes, which are widely available to the general population, could increase daily non-exercise activity thermogenesis as the result of increased muscular involvement. We compared the energy expenditure of obese patients during standing and walking with conventional flat-bottomed shoes versus unstable shoes.

METHODS

Twenty-nine obese patients were asked to stand quietly and to walk at their preferred walking speed while wearing unstable or conventional shoes. The main outcome measures were metabolic rate of standing and gross and net energy cost of walking, as assessed with indirect calorimetry.

RESULTS

Metabolic rate of standing was higher while wearing unstable shoes compared with conventional shoes (1.11 ± 0.20 W/kg(-1) vs 1.06 ± 0.23 W/kg(-1), P=.0098). Gross and net energy cost of walking were higher while wearing unstable shoes compared with conventional shoes (gross: 4.20 ± 0.42 J/kg(-1)/m(-1)vs 4.01 ± 0.39 J/kg(-1)/m(-1), P=.0035; net: 3.37 ± 0.41 J/kg(-1)/m(-1) vs 3.21 ± 0.37 J/kg(-1)/m(-1); P=.032).

CONCLUSION

In obese patients, it is possible to increase energy expenditure of standing and walking by means of ergonomic unstable footwear. Long-term use of unstable shoes may eventually prevent a positive energy balance.

Standing balance in patients with whiplash-associated neck pain and idiopathic neck pain when compared with asymptomatic participants: A systematic review

Neck proprioception is one of the information sources that helps regulate postural balance. However, it is believed to be impaired as patients with both idiopathic neck pain (INP) and whiplash-associated disorders (WAD) have been shown to have a more unstable balance than healthy controls. This systematic review aims to determine if there are significant differences in balance between patients with INP and healthy controls and between patients with WAD and healthy controls. Studies were sought from PubMed, Cinahl, Physiotherapy Evidence Database, Web of Science, Academic Search Complete, Science Direct, and Scielo. Two reviewers independently screened titles and abstracts, assessed full reports for potentially eligible studies, and extracted information on participants' characteristics, pain characteristics, study methods, study results, and study quality. Twelve studies were included in this systematic review. Of these, six compared INP and healthy controls and eight compared WAD and healthy controls. All but one study (11/12) found a statistically significant difference for at least one measurement between patients with INP and WAD and healthy controls. The results of this systematic review suggest that both patients with INP and patients with WAD have poorer balance than healthy controls.

Independent effects of adding weight and inertia on balance during quiet standing

Background

Human balance during quiet standing is influenced by adding mass to the body with a backpack, with symmetrically-applied loads to the trunk, or with obesity. Adding mass to the body increases both the weight and inertia of the body, which theoretically could provide counteracting effects on body dynamics and balance. Understanding the independent effects of adding weight and inertia on balance may provide additional insight into human balance that could lead to novel advancements in balance training and rehabilitation. Therefore, the purpose of this study was to investigate the independent effects of adding weight and inertia on balance during quiet standing.

Methods

Sixteen normal-weight young adult participants stood as still as possible on a custom-built backboard apparatus under four experimental conditions: baseline, added inertia only, added weight only, and added inertia and weight.

Results

Adding inertia by itself had no measurable effect on center of pressure movement or backboard movement. Adding weight by itself increased center of pressure movement (indicated greater effort by the postural control system to stand as still as possible) and backboard movement (indicating a poorer ability of the body to stand as still as possible). Adding inertia and weight at the same time increased center of pressure movement but did not increase backboard movement compared to the baseline condition.

Conclusions

Adding inertia and adding weight had different effects on balance. Adding inertia by itself had no effect on balance. Adding weight by itself had a negative effect on balance. When adding inertia and weight at the same time, the added inertia appeared to lessen (but did not eliminate) the negative effect of adding weight on balance. These results improve our fundamental understanding of how added mass influences human balance.

Biomechanical evaluation of the relationship between postural control and body mass index

Postural stability is crucial in maintaining body balance during quiet standing, locomotion, and any activities that require a high degree of balance performance, such as participating in sports and dancing. Research has shown that there is a relationship between stability and body mass. The aims of this study were to examine the impact that two variables had on static postural control: body mass index (BMI) and gender. Eighty healthy young adults (age=21.7±1.8 yr; height=1.65±0.09 m; mass=67.5±19.0 kg) participated in the study and the static postural control was assessed using the Biodex Balance System, with a 20 Hz sampling rate in the bipedic stance (BLS) and unipedic stance (ULS) for 30s. Five test evaluations were performed for each balance test. Postural control was found to be negatively correlated with increased adiposity, as the obese BMI group performed significantly poorer than the underweight, normal weight and overweight groups during BLS and ULS tests. The underweight, normal weight and overweight groups exhibited greater anterior-posterior stability in postural control during quiet stance. In addition, female displayed a trend of having a greater postural sway than male young adults, although it was evidenced in only some BMI groups. This study revealed that BMI do have an impact on postural control during both BLS and ULS. As such, BMI and gender-specific effects should be taken into consideration when selecting individuals for different types of sporting activities, especially those that require quiet standing.

Effect of moderate physical exercise on postural control among 65-74 years old men

The aim of this study was to assess the changes in the postural control (PC) during quiet stance among elderly men with fatigue induced by moderate exercise, and to assess the relationships between changes in PC and somatic indices (body mass index (BMI), waist to hip ratio (WHR)), load during exercise, and post-exercise blood lactate (BL) concentration. The study involved 17 elderly men (68.4±2.9 years of age, ranging between 65 and 74 years). Mean velocity of the center of pressure (COP) displacements was measured using a force plate both before and after fatigue induced by a cycle ergometer exercise. Following physical exercise, the mean velocity of the COP and its components, both in the sagittal and frontal plane, increased significantly. It was found that increasing BMI was associated with increasing exercise-induced changes in the mean velocity of the frontal plane. Additionally, BL level was positively correlated with changes in the mean velocity of the sagittal plane. Higher post-exercise values of the mean velocity of the COP may suggest a temporary increase in the risk of falls. Therefore, it seems advisable to caution the elderly men in regards to the increased risk of falling following exercise. Analysis showed that the changes in the PC as indicated by the increase in the COP displacements velocity may be related to the level of fatigue (as indicated by BL). Moreover, elderly men possessing a higher BMI may exhibit a tendency toward the greater increase in the postural sway after exercise-induced fatigue.

Does load carriage differentially alter postural sway in overweight vs. normal-weight schoolchildren?

Among a wide range of negative consequences stemming from excess mass in children, recent studies suggest an impairment of postural control, including basic capabilities such as static and dynamic balance. Such impairment may be compounded when additional tasks are performed, such as carrying localized loads as occurs among children using a backpack. To investigate this, postural control was measured among 77 overweight and obese children (6-11 years old), and an equal number of normal-weight children matched for gender, age, and height. Testing was conducted at school, in which center of pressure (COP) time series during quiet standing were obtained in the presence and absence of each student's backpack. A traditional postural control measure derived from COP (mean velocity) did not indicate significant differences between overweight and normal-weight children, regardless of backpack presence. In contrast, a complexity index (derived from multiscale entropy) suggested the existence of different postural strategies and reduced balance capabilities among overweight children, whose consequences need to be further clarified.

Obesity, mechanical and strength relationships to postural control in adolescence

There is preliminary evidence that BMI is positively correlated with movement variability of standing posture. However, this negative effect of obesity on postural control may be mediated by the change in other body scale variables (e.g., mechanical and fitness) that also occur with changes in BMI. This study investigated the influence of selected body scale (height, body mass, BMI), body composition (body fat percentage), mechanical (moment of inertia - MI) and strength (S) variables as predictors of the control of postural motion in adolescents. 125 healthy adolescents (65 boys, 60 girls) with a wide range of BMI (13.8-31.0 kg/m(2)) performed a battery of tests that assessed body composition, anthropometry, muscular strength and postural control. Multiple measures of postural motion variability were derived for analysis with body scale, mechanical and lower extremity strength variables separately for boys and girls. BMI, height and body mass, considered both separately and collectively, were poor and/or inconsistent predictors of variability in all three posture tasks. However, the ratio of lower extremity strength to whole body moment of inertia showed the highest positive correlation to most postural variability measures in both boys and girls and these effects were strongest in the less stable tasks of single leg standing and recovery of stance. Our findings support the hypothesis that diminished lower extremity strength to mechanical constraint ratio compromises the robustness of the strength to body scale relation in movement and postural control.

Obesity is a risk factor for fracture in children but is protective against fracture in adults: a paradox

With the rise in obesity worldwide, an important debate has developed as to whether excess fat has a detrimental or protective effect on skeletal health in children and adults. Obese children appear to be over represented in fracture groups and recent evidence suggests that fat may be detrimental to bone accrual in children, although this effect may be confined to adolescence during rapid skeletal growth. Fat induced alterations in hormonal factors and cytokines during growth may play a pivotal role in disturbing bone accrual. In contrast, the widely accepted opinion is that fat appears to be protective of bone in adults and minimises bone loss in postmenopausal women. Recent evidence suggests that in adults, site specific fat depots may exert differing effects on bone (with visceral fat acting as a pathogenic fat depot and subcutaneous fat exerting protective effects), and that the effects of fat mass on bone and fracture risk may vary by skeletal site; obesity protects against hip and vertebral fractures but is a risk factor for fractures of the humerus and ankle. The incidence of fracture during adolescence is rising and osteoporosis remains a considerable health burden in older adults. Understanding the effects of fat mass on bone during growth and early adulthood is vital in informing future health strategies and pharmacotherapies to optimise peak bone mass and prevent fracture.

The effects of muscle strength on center of pressure-based measures of postural sway in obese and heavy athletic individuals

INTRODUCTION

Obesity affects postural sway during normal quiet standing; however, the reasons for the increased postural sway are unknown. Improving muscular strength is regarded as a potential way to improve postural control, particularly for obese and overweight subjects. The purpose of this investigation is to evaluate the role of muscular strength on postural sway in obese and overweight individuals.

METHODS

Fifteen healthy weight (control group), seventeen obese (obese group) subjects and nine football players (heavy athletic group) participated in this investigation. Isometric knee extension force and postural sway were measured. Muscular strength was calculated in absolute measures as well as relative to body mass (muscular strength to body mass).

RESULTS

The heavy athletic group demonstrated significantly stronger (absolute) lower limb strength (1593.9 N (95% CI 1425.5, 1762.3)) than both the obese (796.2N (95% CI 673.8, 824.5)) and control (694.1N (95% CI 563.7, 824.5)) groups. As well, when muscular strength was expressed as a ratio to body mass the heavy athletic group had significantly higher values (1.27 (95% CI 1.11, 1.43)) than obese (0.78 (95% CI 0.66, 0.89) and control (1.00 (95% CI (0.88, 1.12)) individuals. Despite this, they swayed similarly to the obese (mean center of pressure speed of 0.83 cms(-1) (95% CI 0.72, 0.93) vs. 0.87 cms(-1) (95% CI 0.80, 0.95)), that is, significantly more than the controls (0.60 cms(-1) (95% CI 0.52, 0.68)).

CONCLUSION

Isometric knee extensor strength has a minimal effect on postural sway in heavier athletic individuals during normal quiet stance.

Excess body fat is associated with higher risk of vertebral deformities in older women but not in men: a cross-sectional study

Thinness is a risk factor for fractures, but the effect of obesity on fracture risk is less clear. We found an association between measures of obesity and prevalence and number of vertebral deformities in women but not in men, in a cross-sectional study of 1,011 participants aged 50-80 years.

INTRODUCTION

Low body weight is well recognised as a risk factor for fractures, but the association between overweight and fracture risk is less well described. This cross-sectional study describes the association between measures of obesity and vertebral deformities in 1,011 male and female participants in the Tasmanian Older Adult Cohort study.

METHODS

Vertebral deformities (anterior wedging) of T4-L4 were determined by morphometric dual-emission X-ray absorptiometry. Body fat was assessed as weight, body mass index (BMI), waist-hip ratio (WHR), waist circumference and DXA measures of trunk fat (in percent) and total fat mass.

RESULTS

The mean age of participants was 63 ± 7 years, and mean BMI was 28 ± 5. Prevalent thoracic vertebral deformities were associated with increasing weight [standardised β (Sβ) 0.29, p = 0.003], BMI (Sβ 0.33, p < 0.001), trunk fat (Sβ 0.20, p = 0.03), waist circumference (Sβ 0.19, p = 0.03) and fat mass (Sβ 0.23, p = 0.03), but not the WHR in women, and only with decreasing total fat mass in men. In addition, the number of vertebral deformities increased as weight, BMI or fat mass increased in women (all p < 0.05) but decreased with increasing total fat mass in men. Associations between fat mass and vertebral deformities were mainly linear, but there was some evidence of a threshold effect in women with a BMI ≥ 35.

CONCLUSIONS

There is a deleterious association between increasing amounts of body fat in women but not in men and the prevalence and number of vertebral deformities, which may reflect loading of the thoracic spine.

Obese elderly women exhibit low postural stability: a novel three-dimensional evaluation system

OBJECTIVE

The aim of this study was to evaluate the multisegmental static postural balance of active eutrophic and obese elderly women using a three-dimensional system under different sensory conditions.

METHODS

A cross-sectional study was conducted on 31 elderly women (16 eutrophic and 15 obese) aged 65 to 75 years. The following anthropometric measurements were obtained: weight, height, waist and hip circumference, and handgrip strength. The physical activity level was evaluated using the International Physical Activity Questionnaire. Body composition was measured using the deuterium oxide dilution technique. The Polhemus(®) Patriot (three-dimensional) equipment was used to measure the parameters of postural balance along the anteroposterior and laterolateral axes. The data acquisition involved one trial of 60 s to test the limit of stability and four trials of 90 s each under the following conditions: (1) eyes open, stable surface; (2) eyes closed, stable surface; (3) eyes open, unstable surface; and (4) eyes closed, unstable surface.

RESULTS

For the limit of stability, significant differences were observed in the maximum anteroposterior and laterolateral displacement (p<0.01) and in the parameter maximum anteroposterior displacement in the eyes closed stable surface condition (p<0.01) and maximum anteroposterior and laterolateral displacement in the eyes open unstable surface (p<0.01 and p = 0.03) and eyes closed unstable surface (p<0.01 and p<0.01) conditions.

CONCLUSIONS

Obese elderly women exhibited a lower stability limit (lower sway area) compared with eutrophic women, leaving them more vulnerable to falls.

Balance control during lateral load transfers over a slippery surface

Few studies have measured balance control during manual material handling, and even fewer with environmental cofactors. This study examined the effect of different surface frictions during a stationary manual material handling task. Thirty-six healthy participants completed 180° lateral transfer tasks of a load over high- and low-friction surfaces (μ = 0.86 and μ = 0.16, respectively). Balance measures, stance kinematics and lower extremity muscle activities were measured. Success during the novel slippery surface dichotomised our population, allowing us to investigate beneficial techniques to lateral load transfers over the slippery surface. Stance width reduction by 8 cm and 15° of additional external foot rotation towards the load were used to counter the imbalance created by the slippery surface. There was no clear alteration to lower extremity muscular control to adapt to a slippery surface. Changes in stance seemed to be used successfully to counter a slippery surface during lateral load transfers. STATEMENT OF RELEVANCE: Industries requiring manual material handling where slippery conditions are potentially present have a noticeable increase in injuries. This study suggests stance configuration, more so than any other measure of balance control, differentiates vulnerability to imbalance during material handling over a slippery surface.

Improved postural control after dynamic balance training in older overweight women

BACKGROUND AND AIMS

Many studies have reported a greater frequency of falls among older women than men in conditions which stress balance. Previously, we found an improvement in static balance in older women with an increased support surface area and equal load redistribution on both feet, in response to a dynamic balance training protocol. The aim of the present study was to examine whether the same training program and body composition would have effects on the postural control of older overweight women.

METHODS

Ten healthy women (68.67 ± 5.50 yrs; 28.17 ± 3.35 BMI) participated in a five-week physical activity program. This included dynamic balance exercises, such as heel-to-toe walking in different directions, putting their hands on their hips, eyes open (EO) or closed (EC), with a tablet on their heads, going up and down one step, and walking on a mat. Postural stability was assessed before and after training with an optoelectronic platform and a uni-pedal balance performance test. Body composition of the trunk, upper limbs and lower limbs was measured by bio-impedance analysis.

RESULTS

The mean speed (MS), medial-lateral MS (MS-x), anterior-posterior MS (MS-y), sway path (SP) and ellipse surface area (ESA) of the pressure center was reduced after training in older women. However, only MS, MS-x, MS-y and SP significantly decreased in bipodalic conditions with EO and MS-y also with EC (p<0.05). Instead, in monopodalic conditions, we found a significant reduction in the ESA of both feet with EO and EC. These data were associated with a significant increase in the lean mass of lower limbs and a higher number of participants who improved their ability to maintain unipedal static balance.

CONCLUSIONS

Our dynamic balance training protocol appears to be feasible, safe and repeatable for older overweight women and to have positive effects in improving their lateral and anterior-posterior postural control, mainly acting on the visual and skeletal muscle components of the balance control system.

Effects of obesity and chronic low back pain on gait

Background

Obesity is often associated with low back pain (LBP). Despite empirical evidence that LBP induces gait abnormalities, there is a lack of quantitative analysis of the combined effect of obesity and LBP on gait. The aim of our study was to quantify the gait pattern of obese subjects with and without LBP and normal-mass controls by using Gait Analysis (GA), in order to investigate the cumulative effects of obesity and LBP on gait.

Methods

Eight obese females with chronic LBP (OLG; age: 40.5 ± 10.1 years; BMI: 42.39 ± 5.47 Kg/m²), 10 obese females (OG; age: 33.6 ± 5.2 years; BMI: 39.26 ± 2.39 Kg/m²) and 10 healthy female subjects (CG; age: 33.4 ± 9.6 years; BMI: 22.8 ± 3.2 Kg/m²), were enrolled in this study and assessed with video recording and GA.

Results and Discussion

OLG showed longer stance duration and shorter step length when compared to OG and CG. They also had a low pelvis and hip ROM on the frontal plane, a low knee flexion in the swing phase and knee range of motion, a low dorsiflexion in stance and swing as compared to OG. No statistically significant differences were found in ankle power generation at push-off between OLG and OG, which appeared lower if compared to CG. At hip level, both OLG and OG exhibited high power generation levels during stance, with OLG showing the highest values.

Conclusions

Our results demonstrated that the association of obesity and LBP affects more the gait pattern than obesity alone. OLG were in fact characterised by an altered knee and ankle strategy during gait as compared to OG and CG. These elements may help optimizing rehabilitation planning and treatment in these patients.

[Relationship between unipedal stance test score and center of pressure velocity in elderly]

INTRODUCTION

Frequent falls are one of the most important health problems in the elderly population. The unipedal stance test (UPST), asses postural stability and is used in fall risk measures. Despite this, there is little information about its relationship with posturographic parameters (PP) that characterizes postural stability. Center of pressure velocity (CoPV) is one of the best PP that describes postural stability. The aim of this study was to analyze the relation between UST score and CoPV in elderly population.

MATERIALS AND METHODS

A sample of 38 healthy elderly subjects where divided in two groups according to their UPST score, low performance (LP, n=11) and high performance (HP, n=27). The correlation between UPST score and COP mean velocity (CoPmV), recorded from a posturographic test, was analyzed between both groups.

RESULTS

An inverse correlation between UPST score and CoPmV was found in both groups. However, this was higher in the LP group (r=-0.69, P=.02) compared to the HP (r=-0.39, P=.04).

CONCLUSIONS

Based on the results of this investigation, it may be concluded that the achievement on UPST has an inverse relationship with CoPmV, especially in subjects with low performance in the UPST.

Is there a relationship between pain intensity and postural sway in patients with non-specific low back pain?

Background

Increased center of pressure excursions are well documented in patients suffering from non-specific low back pain, whereby the altered postural sway includes both higher mean sway velocities and larger sway area. No investigation has been conducted to evaluate a relationship between pain intensity and postural sway in adults (aged 50 or less) with non-specific low back pain.

Methods

Seventy-seven patients with non-specific low back pain and a matching number of healthy controls were enrolled. Center of pressure parameters were measured by three static bipedal standing tasks of 90 sec duration with eyes closed in narrow stance on a firm surface. The perceived pain intensity was assessed by a numeric rating scale (NRS-11), an equal number of patients (n = 11) was enrolled per pain score.

Results

Generally, our results confirmed increased postural instability in pain sufferers compared to healthy controls. In addition, regression analysis revealed a significant and linear increase in postural sway with higher pain ratings for all included COP parameters. Statistically significant changes in mean sway velocity in antero-posterior and medio-lateral direction and sway area were reached with an incremental change in NRS scores of two to three points.

Conclusions

COP mean velocity and sway area are closely related to self-reported pain scores. This relationship may be of clinical use as an objective monitoring tool for patients under treatment or rehabilitation.

Body mass index and the risk of acute injury in adolescents

OBJECTIVE

To evaluate the relationship between body mass index (BMI) and acute injury in adolescents.

METHODS

An analysis of cross-sectional data from the Canadian Community Health Survey (CCHS) Cycle 3.1 collected by Statistics Canada in 2005 was conducted. The CCHS is a population-based survey that collects information pertaining to the Canadian population health status, health care use and health determinants. The CCHS Cycle 3.1 included 132,221 respondents, of whom 12,317 were 12 to 17 years of age. Multivariate logistic regression was used to estimate the odds of injury occurrence by BMI categories (obese, overweight and neither).

RESULTS

The association between overweight and obese BMI levels and injury occurrence in the bivariate model was not significant after adjusting for sex, health status, activity levels and socioeconomic status (OR=1.10 [95% CI 0.97 to 1.24] for overweight and OR=1.12 [95% CI 0.92 to 1.37] for obesity). A subanalysis of those with an injury in the past 12 months found an elevated odds of experiencing multiple injuries in the overweight group, after adjusting for age, health status and physical activity level (OR=1.43 [95% CI 1.16 to 1.77]).

CONCLUSION

An increased risk of acute injury in obese and overweight adolescents was not observed. However, the subgroup analysis suggested that multiple injuries are relatively frequent in the overweight BMI group.

Mechanisms underlying center of pressure displacements in obese subjects during quiet stance

Objective

the aim of this study was to assess whether reduced balance capacity in obese subjects is secondary to altered sensory information.

Design

cross sectional study.

Subjects

44 obese (BMI = 40.6 ± 4.6 kg/m² , age = 34.2 ± 10.8 years, body weight: 114,0 ± 16,0 Kg, body height 167,5 ± 9,8 cm) and 20 healthy controls (10 females, 10 males, BMI: 21.6 ± 2.2 kg/m², age: 30.5 ± 5.5 years, body weight: 62,9 ± 9,3 Kg, body height 170,1 ± 5,8 cm) were enrolled.

Measurements

center of pressure (CoP) displacements were evaluated during quiet stance on a force platform with eyes open (EO) and closed (EC). The Romberg quotient (EC/EO) was computed and compared between groups.

Results

we found statistically significant differences between obese and controls in CoP displacements (p < 0.01) and no statistically significant differences in Romberg quotients (p > 0.08).

Conclusion

the increased CoP displacements in obese subjects do not need an hypothesis about altered sensory information. The integration of different sensory inputs appears similar in controls and obese. In the latter, the increased mass, ankle torque and muscle activity may probably account for the higher CoP displacements.

Soleus H-reflex and its relation to static postural control

The Hoffmann reflex (H-reflex) test has been extensively used to investigate the responsiveness of Ia afferent spinal loop in animal and human studies. The H-reflex response is influenced by multiple neural pathways and the assessment of H-reflex variation is a useful tool in understanding the neural mechanisms in control of movement. Recently, several studies have examined the relationship between the H-reflex modulation and postural stability. For example, it has been reported that the amplitude of soleus (SOL) H-reflex is depressed in relation to increased body sway during upright standing on a soft surface compared to that on a solid surface. It has been suggested that the SOL H-reflex modulation under such condition is predominately affected by the presynaptic inhibitory mechanisms for avoiding oversaturation of the spinal motoneurons. It has also been reported that after balance training, the SOL H-reflex amplitude is down-modulated in parallel with improvement in balance control, suggesting a functional adaptation at the supraspinal levels. The aim of this review is to examine the current literature on the relationship between H-reflex modulation and postural control for a better understanding of the physiological mechanisms involved in control of posture in humans.

Neuromuscular Responses to Platform Perturbations in Power-Versus Endurance-Trained Athletes

The purpose was to assess differences in postural response characteristics between two groups of elite athletes having power or endurance training. Participants were all men and included power- ( M age = 21 yr., SD = 3, n = 12) and endurance-trained ( M age = 22, SD = 3, n = 12) athletes. Muscle response characteristics and center of pressure measures were recorded during recovery from Fast (10 cm at 80 cm/sec.) and Slow (10 cm at 20 cm/sec.) horizontal platform perturbations. In response to Fast perturbations, power-trained athletes responded with significantly shorter times to stabilize the center of pressure, shorter muscle-contraction onset times, and larger muscle response amplitudes than endurance-trained athletes. This suggests power-trained athletes are more effective than endurance-trained athletes in responding to balance threats such as slips and trips in daily life and that power training should be studied to improve balance control of balance-impaired populations.

Predictors of Standardized Walking Obstacle Course outcome measures in children with and without developmental disabilities

PURPOSE

This study was designed to determine which characteristics of children predict measures on the Standardized Walking Obstacle Course (SWOC).

METHODS

SWOC testing was performed under 3 conditions: (1) walk, (2) walk with a tray, and (3) walk wearing shaded glasses. Trials consisted of standing up, walking the course in 1 direction, and sitting down. Children (n = 440) completed 2 trials per condition. Trial measures included time, and numbers of steps, stumbles, and steps off the path. Relationships were evaluated using Chi-square analyses and significant predictors were determined by multiple logistic regression analyses. Sensitivity and specificity were calculated to determine the accuracy of disability as a predictor.

RESULTS

Age, weight, and disability were the strongest predictors (P < .05). Increased age and weight predicted shorter time and fewest steps. Disability predicts longer time and most steps.

CONCLUSION

The SWOC is appropriate to screen children for disabilities in functional ambulation.

Characterisation of balance capacity in Prader-Willi patients

Being severely overweight is a distinctive clinical feature of Prader-Willi Syndrome (PWS). This explorative study aims to characterise balance capacity in PWS as compared to non-genetically obese patients (O) and to a group of normal-weight individuals (CG). We enrolled 14 PWS patients: 8 females and 6 males (BMI = 41.3 ± 7.3 kg/m(2), age = 32.86+4.42 years), 44 obese individuals, 22 males and 22 females (BMI = 40.6 ± 4.6 kg/m(2), age = 34.2 ± 10.7 years) and 20 controls (CG: 10 females and 10 males; BMI: 21.6 ± 1.6 kg/m(2); age: 30.5 ± 5.3 years). Postural acquisitions were conducted by means of a force platform from which the COP pattern vs time was analysed. The participants were required to stand barefoot on the platform with eyes open and heels at standardized distance and position for 60s. All of the analysed parameters were statistically different from O and CG groups. PWS individuals showed greater displacements in both the A/P and M/L direction (RMS, RANGE and MV indices). Analysis of the overall planar movement of the CoP showed that the PWS patients were characterised by higher RMS distance from the centre (RMS(CoP) index) and area of confidence ellipse (AREA(CoP) index) when compared both to obese and healthy individuals. PWS patients showed a poorer balance capacity than their non-genetically obese counterparts and healthy individuals, with greater differences in both the A/P and M/L direction than O. Rehabilitation programs for PWS should take this finding into account. In addition to weight loss, strengthening of ankle flexors/extensors, and balance training, tailored interventions aimed at improving A/P control should be given particular consideration.