Olivier Hue

Reducing weight increases postural stability in obese and morbid obese men

Objective:To investigate the effect of weight loss on balance control in obese and morbid obese men.Methods:In a longitudinal and clinical intervention study, postural stability was measured with a force platform before and after weight loss in men. Weight loss was obtained in obese men (mean body mass index (BMI)=33.0 kg/m2) by hypocaloric diet until resistance and in morbid obese men (mean BMI=50.5 kg/m2) by bariatric surgery. Morbid obese men were tested before surgery, and 3 and 12 months after surgery when they had lost 20 and nearly 50% of initial body weight, respectively. Normal weight individuals (mean BMI=22.7 kg/m2) were tested twice within a 6- to 12-month period to serve as control. Body fatness and fat distribution measures, and posturographic parameters of the center of foot pressure (CP) along the antero-posterior and medio-lateral axes for conditions with and without vision were performed in all subjects.Results:Weight loss averaged 12.3 kg after dieting and 71.3 kg after surgery. Body weight remained unchanged in the control group. After weight loss, nearly all measures of postural stability were improved with and without vision (i.e., CP speed and range in antero-posterior and medio-lateral axes). A strong linear relationship was observed between weight loss and improvement in balance control measured from CP speed (adjusted R 2=0.65, P<0.001).Conclusion:Weight loss improves balance control in obese men and the extent of the improvement is directly related to the amount of weight loss. This should decrease the habitual greater risk of falling observed in obese individuals.

Influence of obesity on accurate and rapid arm movement performed from a standing posture.

Introduction:Obesity yields a decreased postural stability. The potentially negative impact of obesity on the control of upper limb movements, however, has not been documented. This study sought to examine if obesity imposes an additional balance control constraint limiting the speed and accuracy with which an upper limb goal-directed movement performed from an upright standing position can be executed.Method:Eight healthy lean subjects (body mass index (BMI) between 20.9 and 25.0 kg/m2) and nine healthy obese subjects (BMI between 30.5 and 48.6 kg/m2) pointed to a target located in front of them from an upright standing posture. The task was to aim at the target as fast and as precisely as possible after an auditory signal. The difficulty of the task was varied by using different target sizes (0.5, 1.0, 2.5 and 5.0 cm width). Hand movement time (MT) and velocity profiles were measured to quantify the aiming. Centre of pressure and segmental kinematics were analysed to document postural stability.Results:When aiming, the forward centre of pressure (CP) displacement was greater for the obese group than for the normal BMI group (4.6 and 1.9 cm, respectively). For the obese group, a decrease in the target size was associated with an increase in backward CP displacement and CP peak speed whereas for the normal BMI group backward CP displacements and CP peak speed were about the same across all target sizes. Obese participants aimed at the target moving their whole body forward whereas the normal BMI subjects predominantly made an elbow extension and shoulder flexion. For both groups, MT increased with a decreasing target size. Compare to the normal BMI group, this effect was exacerbated for the obese group. For the two smallest targets, movements were on average 115 and 145 ms slower for the obese than for the normal BMI group suggesting that obesity added a balance constraint and limited the speed with which an accurate movement could be done.Summary:Obesity, because of its effects on the control of balance, also imposes constraints on goal-directed movements. From a clinical perspective, obese individuals might be less efficient and more at risk of injuries than normal weight individuals in a large number of work tasks and daily activities requiring upper limb movements performed from an upright standing position.

Increased Plasma Levels of Toxic Pollutants Accompanying Weight Loss Induced by Hypocaloric Diet or by Bariatric Surgery

Background: Weight loss reduces the risk of several diseases. Increases of plasma organochlorine and pesticide compounds, however, have been observed with weight loss induced by a dietary intervention and by a gastroplasty. This increased concentration of toxic pollutants could be a side-effect of weight loss and a risk for health problems. The aim of this study was: 1) to observe if there is a relationship between the plasma concentration of organochlorines and BMI at steady state weight, and 2) to determine, after a bariatric surgical intervention, if the magnitude of the weight loss has a direct effect on this concentration. Methods: Weight loss was obtained in obese individuals by a hypocaloric diet program until resistance and in morbidly obese individuals by a bariatric operation (biliopancreatic diversion - duodenal switch [BPD-DS]). Normal-weight individuals were tested to serve as controls. Blood samples were analyzed for organochlorine and pesticide compounds at baseline in all groups, after resistance to weight loss in obese individuals, and at 3 months and 1 year after surgery in morbidly obese individuals. Results: At steady state weight, organochlorine and pesticide compounds were found in all groups, and the sum of all organochlorine compounds correlated with age and not BMI. Weight loss averaged 12.1% of the initial body weight after dieting and 20.9% at 3 months after surgery, respectively. This weight loss yielded significant increases in total plasma organochlorine concentration (increase of 23.8% for obese and 51.8% for morbidly obese individuals). For morbidly obese individuals, the weight loss at 1 year after surgery (46.3%) yielded a 388.2% increase in total plasma organochlorine concentration. Conclusion: Plasma organochlorine concentration increases with weight loss and is related to the magnitude. Future research will have to determine if: 1) this pollutant concentration remains elevated over time and 2) there are long-term effects of this high concentration on health.

Weight loss and muscular strength affect static balance control

Objective:Overweight individuals sway more than normal weight individuals. Major weight loss improves their balance control despite a related decrease in muscle strength. Presumably, muscular strength is an important factor for balance control. This study investigated the effect that a change in body mass has on relative strength and balance control.Methodology:Force (isometric knee extension) and balance control (center of pressure speed and range) were studied in three groups; normal weight (BMI <25 kg m−2), obese (30 kg m−2 <BMI< 40 kg m−2) and excess obese (BMI >40 kg m−2) Caucasian male individuals.Results:The excess obese individuals who underwent bariatric surgery as a weight loss strategy were studied before, 3 and 12 months after losing on average, 66.9 kg (±95% CI 55.8, 77.9 kg; on average, 45% of their weight). The obese individuals who underwent diet modifications were studied before dieting and when resistance to weight loss occurred after losing on average 11.7 kg (±95% CI 9.3, 14.2 kg; on average, 12% of their weight). The control group was studied twice, 50 weeks apart. In obese and excess obese individuals, losing weight reduced absolute knee muscular strength on average, by 8.2 kg (±95% CI 3.9, 12.5 kg; on average, 10% of their strength) and 23.9 kg (±95% CI 12.1, 35.8 kg; on average, 33% of their strength). However, it also increased balance control measured with speed of the center of foot pressure, on average, by 0.10 cm s–1 (±95% CI 0.05, 0.14 cm s–1; or increased of 12%) and 0.28 cm s–1 (±95% CI 0.07, 0.47 cm s–1; increased of 27%), respectively. Relative strength increased approximately by 22% for only the excess obese group 12 months post surgery.Conclusion:This suggests, in overweight individuals, weight loss is more efficient at improving balance control than increasing, or even maintaining muscle strength. In these individuals, training programs aimed at improving balance control should primarily target weight loss.

Effects of a physical activity program on postural stability in older people

Background and aims: The objective of this non-randomized study was to determine the influence of a specific physical activity program on the postural stability of older people. Methods: Seventy-four subjects (72.4±0.7 yrs) participated in an individualized three-month physical activity program designed to improve posture, balance and mobility — the PBM program. Sessions were held twice weekly. Postural stability was assessed using a force platform, subjects being in static and dynamic conditions, and with open and closed eyes. Changes in stabilometric parameters (Sway area, ML mean, AP mean, Total length, ML length and AP length) of the intervention group were compared to those of 14 control subjects (71.8±1.5 years). Results: A two-way analysis of variance with repeated measures did not show any significant post-program change in postural stability in the hard floor condition. In contrast, Sway area (p<0.0005), Total length (p<0.001) and AP length (p<0.01) were significantly reduced after the training program in the foam floor condition, with open and closed eyes. In addition, in the mediolateral axis condition and with closed eyes, AP length in the intervention group was significantly reduced (p<0.01, and in the antero-posterior axis condition with both open and closed eyes, Sway area (p<0.0005), Total length (p<0.0005) and AP length (p<0.05) decreased significantly. Conclusions: As shown by the results in the foam floor and dynamic conditions, our individualized physical activity program improved the postural stability of older people when the standing position was challenged. However, the lack of significant results for the hard floor condition suggests that three months is not sufficient to improve static balance. The PBM physical activity program can be used for balance training in older people, but further studies are required to determine the time needed to effect improvements in static balance in this population.

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.

Effets de l’obésité sur la régulation posturale d’adolescentes. Étude préliminaire

Resume Objectif. – Le but de cette etude est de definir l’influence de l’obesite sur les valeurs de regulations posturales statiques d’adolescentes. Methode. – Neuf sujets obeses et sept non obeses ont ete caracterises par les parametres stabilometriques de surface, de longueur et position moyenne du centre de pression plantaire (CPP) dans les deux axes anteroposterieur et mediolateral. L’examen est repete 2 fois, les yeux ouverts puis les yeux fermes, dans les deux situations sans et avec un support en mousse. Resultats. – Des differences significatives de longueur sont observees entre les deux groupes en condition les yeux ouverts (p Conclusion. – Lorsque le sujet est soumis a une perturbation externe, une surcharge ponderale semble etre un facteur perturbateur du controle postural chez des adolescentes obeses. L’influence de la repartition de la masse grasse sur la regulation posturale n’a pu etre mise en evidence.

Obesity Alters Balance and Movement Control

Epidemic excess of weight is considered as a critical and common health problem. It is associated with many physiological and psychological disorders. Other than metabolic problems, obesity also affects the efficient execution of daily living activities such as the simple act of standing, walking or grabbing an object while standing. This article aims at presenting a state of knowledge of recent studies illustrating the detrimental effect of obesity and the beneficial effect of weight loss on postural stability and on the speed and accuracy of upper-limb goal-directed movements performed from a standing posture. Evidence supporting the suggestion that greater strength and training, at least for standing conditions, do not overcome the functional limitations imposed by obesity are presented. It is suggested that obese individuals may suffer from a reduced plantar sole sensitivity. As a conclusion to this work, we confirm the deleterious effect of overweight on motor control as weight loss translates into an improved balance control and upper limb speed-accuracy performance when standing.

Predictors of weight loss in Parkinson's disease: Is weight loss the chicken or the egg?

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Prevalence of overweight and obesity among children and adolescents with intellectual disabilities: A systematic review and meta-analysis

Although there have been numerous studies examining the prevalence of overweight and obesity among children and adolescents with intellectual disabilities, they have not yet been integrated and synthesized through a systematic quantitative review process. The purpose of this systematic review and meta‐analysis was to determine: (i) the prevalence of overweight/obesity among children and adolescents with intellectual disabilities; (ii) the sources of heterogeneity in studies reporting the prevalence of overweight/obesity in this population; and (iii) the risk of overweight/obesity in this population compared with their typically developing peers. A systematic literature search was performed and 16 studies, published between 1985 and 2015, met the inclusion criteria. The resulting pooled prevalence estimates for overweight, overweight–obesity and obesity were respectively: (i) 15%, 30%, and 13%, in children; and (ii) 18%, 33%, and 15% in adolescents. Subgroup analyses showed significant variations in the pooled prevalence estimates as a function of geographical region, recruitment setting, additional diagnoses, and norms used to define overweight or obesity. The findings also showed adolescents with intellectual disabilities to be respectively 1.54 and 1.80 times more at risk of overweight–obesity and obesity than typically developing adolescents. Unfortunately, no such comparison is available for children.