Ana Cristina R. Lacerda

Functional Performance and Inflammatory Cytokines After Squat Exercises and Whole-Body Vibration in Elderly Individuals With Knee Osteoarthritis

OBJECTIVE To investigate the effects of squat exercises combined with whole-body vibration on the plasma concentration of inflammatory markers and the functional performance of elderly individuals with knee osteoarthritis (OA). DESIGN Clinical, prospective, randomized, single-blinded study. SETTING Exercise physiology laboratory. PARTICIPANTS Elderly subjects with knee OA (N=32) were divided into 3 groups: (1) squat exercises on a vibratory platform (platform group, n=11); (2) squat exercises without vibration (squat group, n=10); and (3) the control group (n=11). INTERVENTIONS The structured program of squat exercises in the platform and squat groups was conducted 3 times per week, on alternate days, for 12 weeks. MAIN OUTCOME MEASURES Plasma soluble tumor necrosis factor-α receptors 1 (sTNFR1) and 2 (sTNFR2) were measured using immunoassays (the enzyme-linked immunosorbent assay method). The Western Ontario and McMaster Universities Osteoarthritis Index questionnaire was used to evaluate self-reported physical function, pain, and stiffness. The 6-minute walk test, the Berg Balance Scale, and gait speed were used to evaluate physical function. RESULTS In the platform group, there were significant reductions in the plasma concentrations of the inflammatory markers sTNFR1 and sTNFR2 (P<.001 and P<.05, respectively) and self-reported pain (P<.05) compared with the control group, and there was an increase in balance (P<.05) and speed and distance walked (P<.05 and P<.001, respectively). In addition, the platform group walked faster than the squat group (P<.01). CONCLUSIONS The results suggest that whole-body vibration training improves self-perception of pain, balance, gait quality, and inflammatory markers in elderly subjects with knee OA.

Evidence that brain nitric oxide inhibition increases metabolic cost of exercise, reducing running performance in rats.

To assess the role of nitric oxide (NO) in the metabolic rate and running performance of rats submitted to exercise on a treadmill, 1.43 micromol (2 microL) of Nomega-nitro-L-arginine methyl ester (L-NAME, n=6), a NO synthase inhibitor, or 2 microL of 0.15M NaCl (SAL, n=6) was injected into the lateral cerebral ventricle of male Wistar rats immediately before the animals started running (18m min(-1), 5% inclination). Oxygen consumption (VO2) was measured at rest, during the exercise until fatigue and thereafter during the 30 min of recovery using the indirect calorimetry system. Mechanical efficiency (ME) was also calculated during the running period. During the first 11 min of exercise, there was a similar increase in VO2 while ME remained the same in both groups. Thereafter, VO2 remained stable in the SAL group but continued to increase and remained higher in the L-NAME group until fatigue. The L-NAME-treated rats also showed a sharper decrease in ME than controls. In addition, there was a significant reduction in workload performance by L-NAME-treated animals compared to SAL-treated animals. This suggests that central blockage of nitric oxide increases metabolic cost during exercise, reduces mechanical efficiency and decreases running performance in rats.

Nitric oxide pathway is an important modulator of heat loss in rats during exercise

To assess the role of nitric oxide (NO) in central thermoregulatory mechanisms during exercise, 1.43 micromol (2 microL) of N(omega)-nitro-L-arginine methyl ester (L-NAME, n=6), a NO synthase inhibitor, or 2 microL of 0.15M NaCl (SAL, n=6) was injected into the lateral cerebral ventricle of male Wistar rats immediately before the animals started running (18 m min(-1), 5% inclination). Core (Tb) and skin tail (Ttail) temperatures were measured. Body heating rate (BHR), threshold Tb for tail vasodilation (TTbV), and workload (W) were calculated. During the first 11 min of exercise, there was a greater increase in Tb in the L-NAME group than in the SAL group (BRH=0.17+/-0.02 degrees C min(-1), L-NAME, versus 0.09+/-0.01 degrees C min(-1), SAL, p<0.05). Following the first 11 min until approximately 40 min of exercise, Tb levels remained stable in both groups, but levels remained higher in the L-NAME group than in the SAL group (39.16+/-0.04 degrees C, L-NAME, versus 38.33+/-0.02 degrees C, SAL, p<0.01). However, exercise went on to induce an additional rise in Tb in the SAL group prior to fatigue. These results suggest that the reduced W observed in L-NAME-treated rats (10.8+/-2.0 kg m, L-NAME, versus 25.0+/-2.1 kg m, SAL, p<0.01) was related to the increased BHR in L-NAME-treated animals observed during the first 11 min of exercise (r=0.74, p<0.01) due to the change in TTbV (39.12+/-0.24 degrees C, L-NAME, versus 38.27+/-0.10 degrees C, SAL, p<0.05). Finally, our data suggest that the central nitric oxide pathway modulates mechanisms of heat dissipation during exercise through an inhibitory mechanism.

The Effect of Adding Whole-Body Vibration to Squat Training on the Functional Performance and Self-Report of Disease Status in Elderly Patients with Knee Osteoarthritis: A Randomized, Controlled Clinical Study

OBJECTIVES The study objectives were to evaluate the effects of adding whole-body vibration to squat training on functional performance and self-report of disease in elderly individuals with knee osteoarthritis (OA). DESIGN This was a prospective, randomized trial in which selected variables were evaluated at three periods: 3 weeks prior to the training, immediately prior, and after the end of the training. SUBJECTS Twenty-three (23) elderly subjects were evaluated using four functional performance tests: Berg Balance Scale (BBS), Timed Get Up and Go Test (TGUG), Chair Stand Test (CST), and 6-Minute Walk Test (6MWT), and a self-report of the status of disease (WOMAC). INTERVENTIONS The intervention lasted for 12 weeks, 3 times per week. The participants were randomized into two groups: (1) squat training with whole-body vibration, and (2) squat training without vibration. RESULTS Although there was no statistical difference in functional performance and self-report of disease status between the groups, performance in all the functional tests and in all the domains of WOMAC improved in the vibration group compared to their initial status. In the exercise group, performance improved only two tests (BBS and 6MWT), and there was a reduction in self-reported pain (WOMAC) compared to their initial status. CONCLUSIONS Although the addition of whole-body vibration to squat training failed to result in a significant improvement in functional performance and self-reported status of knee osteoarthritis in the elderly, the intragroup results suggest that whole-body vibration may represent a feasible and effective way of improving the functionality and self-perception of disease status in older adults with knee OA.

Central nitric oxide inhibition modifies metabolic adjustments induced by exercise in rats.

The influence of the central nervous system on metabolic function is of interest in situations deviating from basal states, such as during exercise. Our previous study in rats demonstrated that central nitric oxide (NO) blockade increases metabolic rate, reducing mechanical efficiency during exercise. To assess the role of brain nitric oxide in the plasma glucose, lactate and free fatty acids (FFAs) concentrations of rats submitted to an incremental exercise protocol on a treadmill until fatigue, 1.43 micromol (2 microl) of N(omega)-nitro-l-arginine methyl ester (L-NAME, n=6), a NO synthase inhibitor, or 2 microl of 0.15M NaCl (SAL, n=6) was injected into the lateral cerebral ventricle (icv) of male Wistar rats immediately before exercise (starting at 10 m/min, with increments of 1m/min every 3 min until fatigue, 10% inclination). Blood samples were collected through a chronic jugular catheter at rest and during exercise until fatigue. During exercise, the L-NAME-treated animals had the following metabolic response compared to controls: (1) an increased hyperglycemic response during the first 60% of time to fatigue; (2) higher plasma lactate levels; and (3) a significant transitory increase in plasma free fatty acids during the dynamic phase of exercise that returned to basal levels earlier than controls during the steady state phase of exercise. In addition L-NAME-treated rats fatigued earlier than controls. The data indicate that the inhibition of the brain nitrergic system induced by icv L-NAME treatment disrupted the accuracy of the neural mechanism that regulates plasma glucose and free fatty acids mobilization during exercise in rats.

Central AT1 receptor blockade increases metabolic cost during exercise reducing mechanical efficiency and running performance in rats

The effect of central angiotensin AT(1) receptor blockade on metabolic rate and running performance in rats during exercise on a treadmill (18 m x min(-1), 5% inclination) was investigated. Oxygen consumption (VO(2)) was measured, using the indirect calorimetry system, while the animals were exercising until fatigue after injection of 2 microL of losartan (Los; 60 nmol, n=9), an angiotensin II AT(1) receptor antagonist, or 2 microL of 0.15 M NaCl (Sal, n=9) into the right lateral cerebral ventricle. Mechanical efficiency (ME) and workload (W) were calculated. The W performance by Los-treated animals was 29% lesser than in Sal-treated animals (p<0.02). During the first 10 min of exercise (dynamic state of exercise), there was a similar increase in VO(2), while ME remained the same in both groups. Thereafter (steady state of exercise), VO(2) remained stable in the Sal group but continued to increase and stabilized at a higher level in Los-treated animals until fatigue. During the steady state of exercise there was a sharper reduction in ME in Los-treated rats compared to Sal-treated animals (p<0.01) that was closely correlated to W (r=0.74; p<0.01). Our data showed that AT(1) receptor blockade increases metabolic cost during exercise, reducing mechanical efficiency. These results indicate that central angiotensinergic transmission modulates heat production, improving ME during the steady state of exercise.

Influence of the knee flexion on muscle activation and transmissibility during whole body vibration.

The influence of the knee flexion on muscle activation and transmissibility during whole body vibration is controversially discussed in the literature. In this study, 34 individuals had electromyography activity (EMG) of the vastus lateralis and the acceleration assessed while squatting with 60° and 90° of knee flexion either with or without whole-body vibration (WBV). The conditions were maintained for 10s with 1min of rest between each condition. The main findings were (1) the larger the angle of knee flexion (90° vs. 60°), the greater the EMG (p<0.001), with no difference on acceleration transmissibility; (2) for both angles of knee flexion, the addition of WBV produced no significant difference in EMG and higher acceleration compared to without WBV (p<0.001). These results suggest that the larger the knee flexion angle (60° vs. 90°), the greater the muscle activation without acceleration modification. However, the addition of WBV increases the transmissibility of acceleration in the lower limbs without modification in EMG of vastus lateralis.

Central angiotensin AT1 receptors are involved in metabolic adjustments in response to graded exercise in rats

To investigate the influence of central angiotensin AT1-receptors blockade on metabolic adjustments during graded exercise, Losartan (Los) was intracerebroventricularly injected in rats before running until fatigue. Oxygen consumption (VO2) was measured (n=6) and blood samples collected (n=7) to determine variations of glucose, lactate and free fatty acids (FFA). Los-rats exhibited a hyperglycemic response, already observed at 20% of maximal work, followed by a higher lactate levels and FFA mobilization from adipose tissue. Despite the reduced total time to fatigue and the higher VO2 associated with reduced mechanical efficiency, exercise led to the attainment of similar levels of effort in both groups. In summary, central AT1-receptor blockade during graded exercise induces hyperglycemia and higher FFA mobilization from adipose tissue at low exercise intensities in rats running at the same absolute exercise intensity. These data suggest that the central angiotensinergic system is involved in metabolic adjustments during exercise since central blockade of AT1-receptors shifts energy balance during graded exercise, similarly to situations of higher and premature sympathetic activation.

The effects of passive warm-up vs. whole-body vibration on high-intensity performance during sprint cycle exercise.

Abstract Avelar, NCP, Costa, SJ, da Fonseca, SF, Tossige-Gomes, R, Gripp, FJ, Coimbra, CC, and Lacerda, ACR. The effects of passive warm-up vs. whole-body vibration on high-intensity performance during sprint cycle exercise. J Strength Cond Res 26(11): 2997–3003, 2012—The purpose of this study was to compare the effects of passive warm-up (PW), whole-body vibration (WBV), and control (C) on high-intensity performance during sprint cycle exercise. Six recreationally trained men performed a 30-second sprint cycle test after the 3 aforementioned conditions; each test was carried out on a different day after balanced-order experimental tests. The WBV consisted of 5 minutes of squats associated with WBV (45 Hz, 2 mm). The PW consisted of 30 minutes of PW using a thermal blanket on the thighs and legs (35 W). The C consisted of 30 minutes of no warm-up with the subject lying down. Motor neuron excitability from the vastus lateralis muscle, evaluated by electromyography (EMG), was determined before exercise at rest and during sprint cycle exercise. Blood lactate levels (BLs), evaluated by spectroscopy, and muscle temperature (MT) of the thigh, estimated indirectly by measuring skin temperature, were determined at following time points: before exercise at rest (before and after experimental conditions), immediately, and 3 minutes after the 30-second sprint cycle test. Peak power, relative power, relative work, time of peak power, and pedaling cadence were significantly higher in the WBV compared with that for C (p < 0.05). Although MT was significantly greater in PW compared with that in WBV and C before exercise (p < 0.01), no significant differences were observed between the experimental conditions for BL immediately after sprint cycle exercise (p = 0.35) and in EMG during sprint cycle exercise (p = 0.16). Thus, it is plausible to suggest WBV as a method for an acute increase in high-intensity performance during sprint cycle exercise for athletes immediately before competition or training.

Whole-body vibration decreases the proliferativeb response of TCD4+ cells in elderly individuals with knee osteoarthritis

The aim of this study was to investigate the effect of adding whole-body vibration (WBV; frequency = 35 to 40 Hz; amplitude = 4 mm) to squat training on the T-cell proliferative response of elderly patients with osteoarthritis (OA) of the knee. This study was a randomized controlled trial in which the selected variables were assessed before and after 12 weeks of training. Twenty-six subjects (72 ± 5 years of age) were divided into three groups: 1) squat training with WBV (WBV, N = 8); 2) squat training without WBV (N = 10), and 3) a control group (N = 8). Women who were ≥60 years of age and had been diagnosed with OA in at least one knee were eligible. The intervention consisted of 12 uninterrupted weeks of squatting exercise training performed 3 times/week. Peripheral blood mononuclear cells were obtained from peripheral blood collected before and after training. The proliferation of TCD4+ and TCD8+ cells was evaluated by flow cytometry measuring the carboxyfluorescein succinimidyl ester fluorescence decay before and after the intervention (Δ). The proliferative response of TCD4+ cells (P = 0.02, effect size = 1.0) showed a significant decrease (23%) in the WBV group compared to the control group, while there was no difference between groups regarding the proliferative response of TCD8+ cells (P = 0.12, effect size = 2.23). The data suggest that the addition of WBV to squat exercise training might modulate T-cell-mediated immunity, minimizing or slowing disease progression in elderly patients with OA of the knee.