Recent epidemiological studies report that obesity is positively related to fracture incidence. In the present experiment, a model of postural control was used to examine the impact of an abnormal distribution of body fat in the abdominal area upon postural stability. Obese and lightweight humanoids were destabilized by imposing a small initial angular speed from a neutral standing position. To avoid a loss of stability yielding a stepping reaction or a fall, an ankle torque is necessary to counteract the perturbation. Three torque parameters--ankle torque onset, time to peak torque, and muscular ankle torque--were entered in a program to simulate the intrinsic variability of the human postural control system. A loss of stability was detected when the center of pressure exceeded stability margins. The most striking observation is the nonlinear increase of torque needed to stabilize the humanoid when the motor response was characterized by delayed temporal parameters. The effect was more pronounced when an anterior position of the center of mass was included in the simulations. This suggests that, when submitted to daily postural stresses and perturbations, obese persons (particularly those with an abnormal distribution of body fat in the abdominal area) may be at higher risk of falling than lightweight individuals.

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Participants in this study showed significant improvements in walking speed and walking endurance after 6 months of TT. Improvements were observed after 3 months of intensive TT and persisted at 6 months. It appears that individuals with poorer baseline performance may benefit most from TT.

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 015, age070.8±5.5 years; BMI022.2±1.9 kg/m 2 ), overweight (n 015, age 071.7 ± 4.3 years; BMI 027.3 ± 1.3 kg/m 2 ), and obese (n015, age071.1±4.3 years; BMI033.1±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.

"Change-in-support" (CIS) balance-recovery reactions that involve rapid stepping or reaching movements play a critical role in preventing falls; however, age-related deficits in the neuro-musculoskeletal systems may impede ability to execute these reactions effectively. This review describes four new interventions aimed at reducing fall risk in older adults by promoting more effective CIS reactions: (1) balance training, (2) balance-enhancing footwear, (3) safer mobility aids, and (4) handrail cueing systems. The training program uses unpredictable support-surface perturbations to counter specific CIS control problems associated with aging and fall risk. Pilot testing has demonstrated that the program is well-tolerated by balance-impaired older adults, and a randomized controlled trial is now in progress. The balance-enhancing footwear insole improves control of stepping reactions by compensating for age-related loss of plantar cutaneous sensation. In a clinical trial, subjects wore the insole for 12 weeks with no serious problems and no habituation of the balance-enhancing benefits. The mobility-aid intervention involves changes to the design of pickup walkers so as to reduce impediments to lateral stepping. Finally, work is underway to investigate the effectiveness of handrail cueing in attracting attention to the rail and ensuring that the brain registers its location, thereby facilitating more rapid and accurate grasping.

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 o25 kg m À2 ), obese (30 kg m À2 oBMIo 40 kg m À2 ) and excess obese (BMI 440 kg m À2 ) 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.

More studies are needed to characterise paramedics' behaviour at work. These studies could allow the development of targeted strategies to prevent health problems reported in paramedics.

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.