Adiposity and Balance Control in the Elderly Mainenti MRM et al. intra-observer errors;11 in addition, the equipment is light- weight, portable, and produces fast results.12 In this method, an imperceptible electric current is applied via surface electrodes and passes through the body; the conductance is then measured. Impedance measurements allow fat-free mass and fat mass to be estimated using validated equations.11,13 Another measurement that is positively correlated with intra-abdominal fat mass is waist circumference, which constitutes a simple method of fat mass measurement that is frequently used by health professionals. Waist circumference is strongly associated with truncal fat, regardless of the site of measurement chosen,14 and increases with age.15 Quiet standing postural control is possible, due to the integration of different sensory systems that deliver information to the central nervous system about how body parts are placed relative to the environment. Stabilometry, an objective method used to evaluate body stability, measures successive two-dimensional coordinates based on the center-of-foot pressure on a force platform and calculates a variety of variables.16 One of the most dangerous aspects of changes in body stability for the elderly is an increased risk of falls. This concern explains the focus on postural balance and aging in the literature over the last ten years;17-21 many researchers have attempted to understand which characteristics significantly disturb bal- ance control and, consequently, tend to increase the incidence of falls. The evaluation of the relationship between balance and adiposity in elderly subjects is important for providing information to health professionals about the characteristics that influence balance control. Aging and obesity are conditions that account for a significant portion of health- care spending.22 Therefore, this research may promote progress in the treatment and prevention of falls, indirectly enhancing the quality of life of elderly individuals. The aim of the present study was to investigate the association between body adiposity as analyzed by body composition and distribution measurements and postural control in elderly women living in Rio de Janeiro, Brazil. It was hypothesized that subjects with a higher level of body adiposity would have a greater center-of-foot pressure displacement during quiet stance. MATERIALS AND METHODS Study Protocol and Subjects This cross-sectional study evaluated 45 women enrolled in the program ‘‘Open University for the Elderly’’ (Universidade Aberta a` Terceira Idade, UNATI) at the Augusto Motta University Center (Centro Universita´rio Augusto Motta, UNISUAM) in Bonsucesso, a northern region of Rio de Janeiro, Brazil. Inclusion criteria were as follows: women over 60 years old who were participating in the UNATI program. For exclusion purposes, all of the elderly women underwent a screening evaluation before the main evaluation, which was conducted by the examiner. Exclusion criteria were as follows: 1) the presence of any implantable electronic or metallic device, such as a pace- maker; 2) musculoskeletal impairments, such as hip or knee pain during 60 seconds of orthostatic posture; 3) neurolo- gical diseases, such as stroke, Parkinson disease, Alzheimer disease and amyotrophic lateral sclerosis; 4) acute dizziness; 5) abnormal accumulation of fluid (edema), mainly in the 1514 CLINICS 2011;66(9):1513-1518 limbs, as assessed by physical examination (inspection and palpation); and 6) when the recommendations described below were not followed. Recommendations and Preliminary Evaluations Body composition and stabilometric assessments were carried out at the Laboratory of Human Movement Anal- ysis (Postgraduate Program of Rehabilitation Sciences, UNISUAM). When the evaluation was scheduled, the following recommendations were discussed with each subject: 1) no alcohol consumption or exercise within 24 hours prior to taking the test; 2) no caffeine or food consumption for four hours prior to the test; 3) the consumption of two-four glasses of water within the two hours prior to the test; 4) bathroom use within the 30 minutes prior to the assessment. The subjects’ weight, rounded to the nearest 0.1 kg, was measured using an analog balance scale (R110, Welmy, Santa Ba´rbara d’Oeste, Sa˜o Paulo, Brazil), and the subjects’ height, rounded to the nearest 0.005 m, was also assessed using this device, which includes a stadiometer. Using the weight and height measurements, the subject’s BMI was calculated using the standard method (BMI = Weight/ Height2).10 Lower limb dominancy was also assessed by asking subjects which leg they preferred to use for kicking a ball. Bioelectrical Impedance Analysis Body composition analysis was performed using a bioelectrical impedance analyzer (BIA 310e, Biodynamics, Seattle, Washington, USA). The test current was set at 800 mA and 50 kHz, which were well below the Association for Advancement of Medical Instrumentation’s standard for "Safe Current Limits". The tetrapolar resistance and reac- tance measurements were collected in a standardized manner; the subjects were asked to rest for five minutes prior to the exam on an examination table. They stood barefoot without any metal objects close to them, and the feet and hands were at least 30 cm and 15 cm apart, respectively. Two electrodes were applied to the dorsal surface of the right hand, and two electrodes were placed on the dorsal surface of the right foot. Resistance and reactance provided by the analyzer were used to estimate the fat-free mass (kg). Additional body composition variables were analyzed, including fat mass (kg) and fat percentage (%). The equation selected to predict the fat-free mass23 was previously validated in elderly samples,11,24 including a Brazilian sample of subjects aged 60-81 years:11 FFM ~ { 4:104 z 0:518 H2=R z 0:231 ðBWÞ z 0:130 ðXcÞ z 4:229 ðGÞ, where FFM = fat-free mass (kg), H = stature (cm), R = resistance (V), BW = body weight (kg), Xc = reactance (V) and G = gender (0 for females and 1 for males). Waist circumference was also measured at the narrowest point between the lower costal border and the iliac crest.25 A flexible steel tape (Terrazul, Cambuci, Sa˜o Paulo, Brazil) was used to verify this girth to the nearest 0.1 cm. Stabilometry Postural sway was quantified using a force platform (AccuSway Plus, AMTI, Watertown, Massachusetts, USA),