Luiz Augusto Riani Costa

Determining the similarity of deformable shapes

Determining the similarity of two shapes is a significant task in both machine and human vision systems that must recognize or classify objects. The exact properties of human shape similarity judgements are not well understood yet, and this task is particularly difficult in domains where the shapes are not related by rigid transformation. In this paper we identify a number of possibly desirable properties of a shape similarity method, and determine the extent to which these properties can be captured by approaches that compare local properties of the contours of the shapes, through elastic matching. Special attention is devoted to objects that possess articulations, i.e. articulated parts. Elastic matching evaluates the similarity of two shapes as the sum of local deformations needed to change one shape into another. We show that similarities of part structure can be captured by such an approach, without the explicit computation of part structure. This may be of importance, since although parts appear to play a significant role in visual recognition, it is difficult to stably determine part structure. We also show novel results about how one can evaluate smooth and polyhedral shapes with the same method. Finally, we describe shape similarity effects that cannot be handled by current approaches.

Resistance training‐induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage

Skeletal muscle hypertrophy is one of the main outcomes from resistance training (RT), but how it is modulated throughout training is still unknown. We show that changes in myofibrillar protein synthesis (MyoPS) after an initial resistance exercise (RE) bout in the first week of RT (T1) were greater than those seen post‐RE at the third (T2) and tenth week (T3) of RT, with values being similar at T2 and T3. Muscle damage (Z‐band streaming) was the highest during post‐RE recovery at T1, lower at T2 and minimal at T3. When muscle damage was the highest, so was the integrated MyoPS (at T1), but neither were related to hypertrophy; however, integrated MyoPS at T2 and T3 were correlated with hypertrophy. We conclude that muscle hypertrophy is the result of accumulated intermittent increases in MyoPS mainly after a progressive attenuation of muscle damage.

Liposuction Induces a Compensatory Increase of Visceral Fat Which Is Effectively Counteracted by Physical Activity: A Randomized Trial

CONTEXT Liposuction is suggested to result in long-term body fat regain that could lead to increased cardiometabolic risk. We hypothesized that physical activity could prevent this effect. OBJECTIVE Our objective was to investigate the effects of liposuction on body fat distribution and cardiometabolic risk factors in women who were either exercise trained or not after surgery. DESIGN, SETTING, AND PARTICIPANTS Thirty-six healthy normal-weight women participated in this 6-month randomized controlled trial at the University of Sao Paulo, Sao Paulo, Brazil. INTERVENTIONS Patients underwent a small-volume abdominal liposuction. Two months after surgery, the subjects were randomly allocated into two groups: trained (TR, n = 18, 4-month exercise program) and nontrained (NT, n = 18). MAIN OUTCOME MEASURES Body fat distribution (assessed by computed tomography) was assessed before the intervention (PRE) and 2 months (POST2), and 6 months (POST6) after surgery. Secondary outcome measures included body composition, metabolic parameters and dietary intake, assessed at PRE, POST2, and POST6, and total energy expenditure, physical capacity, and sc adipocyte size and lipid metabolism-related gene expression, assessed at PRE and POST6. RESULTS Liposuction was effective in reducing sc abdominal fat (PRE vs. POST2, P = 0.0001). Despite the sustained sc abdominal fat decrement at POST6 (P = 0.0001), the NT group showed a significant 10% increase in visceral fat from PRE to POST6 (P = 0.04; effect size = -0.72) and decreased energy expenditure (P = 0.01; effect size = 0.95) when compared with TR. Dietary intake, adipocyte size, and gene expression were unchanged over time. CONCLUSION Abdominal liposuction does not induce regrowth of fat, but it does trigger a compensatory increase of visceral fat, which is effectively counteracted by physical activity.

Strength and power training did not modify cardiovascular responses to aerobic exercise in elderly subjects

Resistance training increases muscle strength in older adults, decreasing the effort necessary for executing physical tasks, and reducing cardiovascular load during exercise. This hypothesis has been confirmed during strength-based activities, but not during aerobic-based activities. This study determined whether different resistance training regimens, strength training (ST, constant movement velocity) or power training (PT, concentric phase performed as fast as possible) can blunt the increase in cardiovascular load during an aerobic stimulus. Older adults (63.9 ± 0.7 years) were randomly allocated to: control (N = 11), ST (N = 13, twice a week, 70-90% 1-RM) and PT (N = 15, twice a week, 30-50% 1-RM) groups. Before and after 16 weeks, oxygen uptake (VO(2)), systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) were measured during a maximal treadmill test. Resting SBP and RPP were similarly reduced in all groups (combined data = -5.7 ± 1.2 and -5.0 ± 1.7%, respectively, P < 0.05). Maximal SBP, HR and RPP did not change. The increase in measured VO(2), HR and RPP for the increment in estimated VO(2) (absolute load) decreased similarly in all groups (combined data = -9.1 ± 2.6, -14.1 ± 3.9, -14.2 ± 3.0%, respectively, P < 0.05), while the increments in the cardiovascular variables for the increase in measured VO(2) did not change. In elderly subjects, ST and PT did not blunt submaximal or maximal HR, SBP and RPP increases during the maximal exercise test, showing that they did not reduce cardiovascular stress during aerobic tasks.

Post-resistance exercise hemodynamic and autonomic responses: Comparison between normotensive and hypertensive men

To compare post‐resistance exercise hypotension (PREH) and its mechanisms in normotensive and hypertensive individuals, 14 normotensives and 12 hypertensives underwent two experimental sessions: control (rest) and exercise (seven exercises, three sets, 50% of one repetition maximum). Hemodynamic and autonomic clinic measurements were taken before (Pre) and at two moments post‐interventions (Post 1: between 30 and 60 min; Post 2: after 7 h). Ambulatory blood pressure (BP) was monitored for 24 h. At Post 1, exercise decreased systolic BP similarly in normotensives and hypertensives (−8 ± 2 vs −13 ± 2 mmHg, P > 0.05), whereas diastolic BP decreased more in hypertensives (−4 ± 1 vs −9 ± 1 mmHg, P < 0.05). Cardiac output and systemic vascular resistance did not change in normotensives and hypertensives (0.0 ± 0.3 vs 0.0 ± 0.3 L/min; −1 ± 1 vs −2 ± 2 U, P > 0.05). After exercise, heart rate (+13 ± 3 vs +13 ± 2 bpm) and its variability (low‐ to high‐frequency components ratio, 1.9 ± 0.4 vs +1.4 ± 0.3) increased whereas stroke volume (−14 ± 5 vs −11 ± 5 mL) decreased similarly in normotensives and hypertensives (all, P > 0.05). At Post 2, all variables returned to pre‐intervention, and ambulatory data were similar between sessions. Thus, a session of resistance exercise promoted PREH in normotensives and hypertensives. Although this PREH was greater in hypertensives, it did not last during the ambulatory period, which limits its clinical relevance. In addition, the mechanisms of PREH were similar in hypertensives and normotensives.

Cardiac Work Remains High after Strength Exercise in Elderly

Moderate- to high-intensity strength training is recommended for healthy adults. In young subjects, a single session of strength training decreases blood pressure, while heart rate and cardiac work remain elevated afterwards. However, these effects have not been clearly demonstrated in elderly subjects. To investigate this issue, 16 elderly subjects each underwent a Control and an Exercise (3 sets, 8 RM, 9 exercises) session conducted in random order. Haemodynamic variables and heart rate variability were measured before and after the interventions. Systolic blood pressure did not change after the exercise session but did increase after the control session (+8.1±1.6 mm Hg, P≤0.05). Diastolic blood pressure, as well as systemic vascular resistance increased similarly after both sessions. Cardiac output and stroke volume decreased, while heart rate, rate-pressure product and the low- to high-frequency ratio of heart rate variability increased only after the exercise session ( - 0.5±0.1 L/min, - 9.3±2.0 ml,+3.8±1.6 bpm, +579.3±164.1 mmHg.bpm and +0.71±0.34, P≤0.05). Ambulatory blood pressure was similar after both sessions, while heart rate and rate pressure product remained higher after the exercise session for up to 4.5 h. After a single session of strength training, cardiac sympathetic modulation and heart rate remain elevated in elderly subjects, keeping cardiac work elevated for a long period of time.

Finger Blood Pressure During Leg Resistance Exercise

Blood pressure (BP) assessment during resistance exercise can be useful to avoid high BP, reducing cardiovascular risk, especially in hypertensive individuals. However, non-invasive accurate technique for this purpose is not available. The aim of this study was to compare finger photoplethysmographic (FPP) and intra-arterial BP values and responses during resistance exercise. Eight non-medicated hypertensive subjects (5 males, 30-60 years) were evaluated during pre-exercise resting period and during three sets of the knee extension exercise performed at 80% of 1RM until fatigue. BP was measured simultaneously by FPP and intra-arterial methods. Data are mean+/-SD. Systolic BP was significantly higher with FPP than with intra-arterial: at pre-exercise (157+/-13 vs. 152+/-10 mmHg; p<0.01) and the mean (202+/-29 vs. 198+/-26 mmHg; p<0.01), and the maximal (240+/-26 vs. 234+/-16 mmHg; p<0.05) values achieved during exercise. The increase in systolic BP during resistance exercise was similar between FPP and intra-arterial (+73+/-29 vs. +71+/-18 mmHg; p=0.59). Diastolic BP values and increases were lower with FPP. In conclusion, FPP provides similar values of BP increment during resistance exercise than intra-arterial method. However, it overestimates by 2.6+/-6.1% the maximal systolic BP achieved during this mode of exercise and underestimates by 8.8+/-5.8% the maximal diastolic BP.

Atenolol blunts blood pressure increase during dynamic resistance exercise in hypertensives

AIMS This study was conducted to determine whether atenolol was able to decrease BP level and mitigate BP increase during dynamic resistance exercise performed at three different intensities in hypertensives. METHODS Ten essential hypertensives (systolic/diastolic BP between 140/90 and 160/105mmHg) were blindly studied after 6 weeks of placebo and atenolol. In each phase, volunteers executed, in a random order, three protocols of knee-extension exercises to fatigue: (i) one set at 100% of 1RM; (ii) three sets at 80% of 1RM; and (iii) three sets at 40% of 1RM. Intra-arterial radial blood pressure was measured throughout the protocols. RESULTS Atenolol decreased systolic BP maximum values achieved during the three exercise protocols (100% = 186 ± 4 vs. 215 ± 7, 80% = 224 ± 7 vs. 247 ± 9 and 40% = 223 ± 7 vs. 252 ± 16mmHg, P < 0.05). Atenolol also mitigated an increase in systolic BP in the first set of exercises (100% =+38 ± 5 vs.+54 ± 9; 80% =+68 ± 11 vs. +84 ± 13 and 40% =+69 ± 7 vs.+84 ± 14, mmHg, P < 0.05). Atenolol decreased diastolic BP values and mitigated its increase during exercise performed at 100% of 1RM (126 ± 6 vs. 145 ± 6 and +41 ± 6 vs.+52 ± 6, mmHg, P < 0.05), but not at the other exercise intensities. CONCLUSIONS Atenolol was effective in both reducing systolic BP maximum values and mitigating BP increase during resistance exercise performed at different intensities in hypertensive subjects.

Effects of Progressive Resistance Training on Cardiovascular Autonomic Regulation in Patients With Parkinson Disease: A Randomized Controlled Trial

OBJECTIVE To evaluate the effects of a progressive resistance training (RT) on cardiac autonomic modulation and on cardiovascular responses to autonomic stress tests in patients with Parkinson disease (PD). DESIGN Randomized clinical trial. SETTING The Brazil Parkinson Association. PARTICIPANTS Patients (N=30) with PD (modified Hoehn & Yahr stages 2-3) were randomly divided into 2 groups: a progressive RT group (PD training [PDT] group) and a control group (PD control [PDC] group). In addition, a group of paired healthy control (HC) subjects without PD was evaluated. INTERVENTIONS The PDT group performed 5 resistance exercises, 2 to 4 sets, 12 to 6 repetitions maximum per set. Individuals in the PDC group maintained their usual lifestyle. MAIN OUTCOME MEASURES The PDT and PDC groups were evaluated before and after 12 weeks. The HC group was evaluated once. Autonomic function was assessed by spectral analysis of heart rate variability and cardiovascular responses to autonomic stress tests (deep breathing, Valsalva maneuver, orthostatic stress). RESULTS Compared with baseline, the normalized low-frequency component of heart rate variability decreased significantly after 12 weeks in the PDT group only (PDT: 61±17 normalized units [nu] vs 47±20nu; PDC: 60±14nu vs 63±10nu; interaction P<.05). A similar result was observed for systolic blood pressure fall during orthostatic stress that also was reduced only in the PDT group (PDT: -14±11mmHg vs -6±10mmHg; PDC: -12±10mmHg vs -11±10mmHg; interaction P<.05). In addition, after 12 weeks, these parameters in the PDT group achieved values similar to those in the HC group. CONCLUSIONS In patients with PD, progressive RT improved cardiovascular autonomic dysfunction.

Exercise-induced bronchoconstriction in elite long-distance runners in Brazil* , **

OBJECTIVE To determine the prevalence of exercise-induced bronchoconstriction among elite long-distance runners in Brazil and whether there is a difference in the training loads among athletes with and without exercise-induced bronchoconstriction. METHODS This was a cross-sectional study involving elite long-distance runners with neither current asthma symptoms nor a diagnosis of exercise-induced bronchoconstriction. All of the participants underwent eucapnic voluntary hyperpnea challenge and maximal cardiopulmonary exercise tests, as well as completing questionnaires regarding asthma symptoms and physical activity, in order to monitor their weekly training load. RESULTS Among the 86 male athletes recruited, participation in the study was agreed to by 20, of whom 5 (25%) were subsequently diagnosed with exercise-induced bronchoconstriction. There were no differences between the athletes with and without exercise-induced bronchoconstriction regarding anthropometric characteristics, peak oxygen consumption, baseline pulmonary function values, or reported asthma symptoms. The weekly training load was significantly lower among those with exercise-induced bronchoconstriction than among those without. CONCLUSIONS In this sample of long-distance runners in Brazil, the prevalence of exercise-induced bronchoconstriction was high.