Cardiovascular adaptive responses in rats submitted to moderate resistance training

The present study investigated the effects of 8 week of resistance training (RT) on hemodynamic and ventricular function on cardiac myosin ATPase activity, and on contractility of papillary muscles of rats. Groups: control (CO), electrically stimulated (ES), trained at 60% (TR 60%) and 75% of one repetition maximum (1RM) (TR 75%). Exercise protocol: 5 sets of 12 repetitions at 60 and 75% of 1RM, 5 times per week. The CO and ES groups had similar values for parameters analyzed (P > 0.05). Blood pressure (BP), heart rate (13%), left ventricle systolic pressure (LVSP 13%) decreased and cardiac myosin ATPase activity increased in the TR 75% group (90%, P < 0.05). The contractile performance of papillary muscles increased in trained rats (P < 0.05). Eight weeks of RT was associated with lowering of resting BP, heart rate and LVSP, improvements in contractility of the papillary muscle and an increase of cardiac myosin ATPase activity in rats.

Strength training improves fall-related gait kinematics in the elderly: a randomized controlled trial

Background: Falls are one of the greatest concerns among the elderly. Among a number of strategies proposed to reduce the risk of falls, improving muscle strength has been applied as a successful preventive strategy. Although it has been suggested as a relevant strategy, no studies have analyzed how muscle strength improvements affect the gait pattern. The aim of this study was to determine the effects of a lower limb strength training program on gait kinematics parameters associated with the risk of falls in elderly women. Methods: Twenty seven elderly women were assigned in a balance and randomized order into an experimental (n = 14: age = 61.1 (4.3) years, BMI = 26.4 (2.8) kg m(-2)) and a control (n = 13; age = 61.6 (6.6) years; BMI = 25.9 (3.0) kg m(-2)) group. The EG performed lower limb strength training during 12 weeks (3 days per week), being training load increased weekly. Findings: Primary outcomes were gait kinematics parameters and maximum voluntary isometric contractions at pre- and post-training period. Secondary outcomes were training load improvement weekly and one repetition maximum every two weeks. The I maximal repetition increment ranged from 32% to 97% and was the best predictor of changes in gait parameters (spatial, temporal and angular variables) after training for the experimental group. Z-score analysis revealed that the strength training was effective in reversing age-related changes in gait speed, stride length, cadence and toe clearance, approaching the elderly to reference values for healthy young women. Interpretation: Lower limb strength training improves fall-related gait kinematic parameters. Thus, strength training programs should be recommended to the elderly women in order to change their gait pattern towards young adults. (C) 2009 Elsevier Ltd. All rights reserved.

Beneficial Effect of Creatine Supplementation in Knee Osteoarthritis

NEVES JR., M., B. GUALANO, H. ROSCHEL, R. FULLER, F. B. BENATTI, A. L. DE SA PINTO, F. R. LIMA, R. M. PEREIRA, A. H. LANCHA JR., E. BONFA. Beneficial Effect of Creatine Supplementation in Knee Osteoarthritis. Med. Sci. Sports Exerc., Vol. 43, No. 8, pp. 1538-1543, 2011. Introduction: The aim of this study was to investigate the efficacy of creatine (CR) supplementation combined with strengthening exercises in knee osteoarthritis (OA). Methods: A randomized, double-blind, placebo-controlled trial was performed. Postmenopausal women with knee OA were allocated to receive either CR (20 g.d(-1) for 1 wk and 5 g.d(-1) thereafter) or placebo (PL) and were enrolled in a lower limb resistance training program. They were assessed at baseline (PRE) and after 12 wk (POST). The primary outcome was the physical function as measured by the timed-stands test. Secondary outcomes included lean mass, quality of life, pain, stiffness, and muscle strength. Results: Physical function was significantly improved only in the CR group (P = 0.006). In addition, a significant between-group difference was observed (CR: PRE = 15.7 +/- 1.4, POST = 18.1 +/- 1.8; PL: PRE = 15.0 +/- 1.8, POST = 15.2 +/- 1.2; P = 0.004). The CR group also presented improvements in physical function and stiffness subscales as evaluated by the Western Ontario and McMaster Universities Osteoarthritis Index (P = 0.005 and P = 0.024, respectively), whereas the PL group did not show any significant changes in these parameters (P > 0.05). In addition, only the CR group presented a significant improvement in lower limb lean mass (P = 0.04) as well as in quality of life (P = 0.01). Both CR and PL groups demonstrated significant reductions in pain (P G 0.05). Similarly, a main effect for time revealed an increase in leg-press one-repetition maximum (P = 0.005) with no significant differences between groups (P = 0.81). Conclusions: CR supplementation improves physical function, lower limb lean mass, and quality of life in postmenopausal women with knee OA undergoing strengthening exercises.

AT(1) receptor participates in the cardiac hypertrophy induced by resistance training in rats

Resistance training is accompanied by cardiac hypertrophy, but the role of the renin-angiotensin system (RAS) in this response is elusive. We evaluated this question in 36 male Wistar rats divided into six groups: control (n = 6); trained (n = 6); control + losartan (10 mg.kg(-1).day(-1), n = 6); trained + losartan (n = 6); control + high-salt diet (1%, n = 6); and trained + high-salt diet (1%, n = 6). High salt was used to inhibit the systemic RAS and losartan to block the AT(1) receptor. The exercise protocol consisted of: 4 x 12 bouts, 5x/wk during 8 wk, with 65-75% of one repetition maximum. Left ventricle weight-to-body weight ratio increased only in trained and trained + high-salt diet groups (8.5% and 10.6%, P < 0.05) compared with control. Also, none of the pathological cardiac hypertrophy markers, atrial natriuretic peptide, and alpha MHC (alpha-myosin heavy chain)-to-beta MHC ratio, were changed. ACE activity was analyzed by fluorometric assay (systemic and cardiac) and plasma renin activity (PRA) by RIA and remained unchanged upon resistance training, whereas PRA decreased significantly with the high-salt diet. Interestingly, using Western blot analysis and RT-PRC, no changes were observed in cardiac AT(2) receptor levels, whereas the AT(1) receptor gene (56%, P < 0.05) and protein (31%, P < 0.05) expressions were upregulated in the trained group. Also, cardiac ANG II concentration evaluated by ELISA remained unchanged (23.27 +/- 2.4 vs. 22.01 +/- 0.8 pg/mg, P > 0.05). Administration of a subhypotensive dose of losartan prevented left ventricle hypertrophy in response to the resistance training. Altogether, we provide evidence that resistance training-induced cardiac hypertrophy is accompanied by induction of AT(1) receptor expression with no changes in cardiac ANG II, which suggests a local activation of the RAS consistent with the hypertrophic response.

Strength Training Preserves the Bone Mineral Density of Postmenopausal Women Without Hormone Replacement Therapy

Objective: The study was designed to evaluate the effects of strength training (ST) on the bone mineral density (BMD) of postmenopausal women without hormone replacement therapy. Method: Subjects were randomized into untrained (UN) or trained (TR) groups. The TR group exercised three ST sessions per week for 24 weeks, and body composition, muscular strength, and BMD of the lumbar spine and femur neck were evaluated. Results: Body weight, mass index, and fat percentage were lower after 24 weeks only in the TR group (p < .05). SR also improved the one repetition maximum test in 46% and 39% of upper and lower limbs, respectively. The percentage of demineralization was higher in the UN group than in the TR group at the lumbar spine and femoral neck (p < .05). Discussion: Results indicated that 24 weeks of ST improved body composition parameters, increased muscular strength, and preserved BMD in postmenopausal women.

Effects of low level laser therapy (808 nm) on physical strength training in humans

Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8 +/- 2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P = 0.033) and in the CG subjects (0.27%, P < 0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P = 0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.

A comparison of peak power in the shoulder press and shoulder throw

The ability to generate peak power is central for performance in many sports. Currently two distinct resistance training methods are used to develop peak power, the heavy weight/slow velocity and light weight/fast velocity regimes. When using the light weight/fast velocity power training method it was proposed that peak power would be greater in a shoulder throw exercise compared with a normal shoulder press. Nine males performed three lifts in the shoulder press and shoulder throw at 30% and 40% of their one repetition maximum (1RM). These lifts were performed identically, except for the release of the bar in the throw condition. A potentiometer attached to the bar measured displacement and duration of the lifts. The time of bar release in the shoulder throw was determined with a pressure switch. ANOVA was used to examine statistically significant differences where the level of acceptance was set at p

Effect of three exercise programs on patients with chronic obstructive pulmonary disease

We compared the effect of three different exercise programs on patients with chronic obstructive pulmonary disease including strength training at 50_80% of one-repetition maximum (1-RM) (ST; N = 11), low-intensity general training (LGT; N = 13), or combined training groups (CT; N = 11). Body composition, muscle strength, treadmill endurance test (TEnd), 6-min walk test (6MWT), Saint George's Respiratory Questionnaire (SGRQ), and baseline dyspnea (BDI) were assessed prior to and after the training programs (12 weeks). The training modalities showed similar improvements (P > 0.05) in SGRQ-total (ST = 13 ± 14%; CT = 12 ± 14%; LGT = 11 ± 10%), BDI (ST = 1.8 ± 4; CT = 1.8 ± 3; LGT = 1 ± 2), 6MWT (ST = 43 ± 51 m; CT = 48 ± 50 m; LGT = 31 ± 75 m), and TEnd (ST = 11 ± 20 min; CT = 11 ± 11 min; LGT = 7 ± 5 min). In the ST and CT groups, an additional improvement in 1-RM values was shown (P < 0.05) compared to the LGT group (ST = 10 ± 6 to 57 ± 36 kg; CT = 6 ± 2 to 38 ± 16 kg; LGT = 1 ± 2 to 16 ± 12 kg). The addition of strength training to our current training program increased muscle strength; however, it produced no additional improvement in walking endurance, dyspnea or quality of life. A simple combined training program provides benefits without increasing the duration of the training sessions.

Do whole-body vibration exercise and resistance exercise modify concentrations of salivary cortisol and immunoglobulin A?

A single bout of resistance exercise (RE) induces hormonal and immune responses, playing an important role in a long-term adaptive process. Whole-body vibration (WBV) has also been shown to affect hormonal responses. Evidence suggests that combining WBV with RE may amplify hormonal and immune responses due to the increased neuromuscular load. Therefore, the aim of this study was to evaluate salivary cortisol (Scortisol) and salivary IgA (SIgA) concentrations following a RE session combined or not with WBV. Nine university students (22.9 ± 5.1 years, 175.8 ± 5.2 cm, and 69.2 ± 7.3 kg) performed five sets of squat exercise (70% one-repetition-maximum) combined (R+V30) or not (R) with WBV at 30 Hz. Saliva samples were obtained before and after exercise. Subjects also rated their effort according to the Borg CR-10 scale (RPE). Data were analyzed by a mixed model. RPE was higher after R+V30 (8.3 ± 0.7) compared to R (6.2 ± 0.7). However, Scortisol (pre: 10.6 ± 7.6 and 11.7 ± 7.6, post: 8.3 ± 6.3 and 10.2 ± 7.2 ng/mL for R and R+V30, respectively) and SIgA concentrations (pre: 98.3 ± 22.6 and 116.1 ± 51.2, post: 116.6 ± 64.7 and 143.6 ± 80.5 µg/mL for R and R+V30, respectively) were unaffected. No significant correlations were observed between Scortisol and RPE (r = 0.45, P = 0.22; r = 0.30, P = 0.42, for R and R+V30, respectively). On the basis of these data, neither protocol modified salivary cortisol or IgA, although RPE was higher after R+V30 than R.

Relationship of upper-limb and thoracic muscle strength to 6-min walk distance in COPD patients

Study objectives: This study was developed to investigate the influence of thoracic and upperlimb muscle function on 6-min walk distance (6MWD) in patients with COPD.Design: A prospective, cross-sectional study.Setting: the pulmonary rehabilitation center of a university hospital.Patients: Thirty-eight patients with mild to very severe COPD were evaluated.Measurements and results: Pulmonary function and baseline dyspnea index (BDI) were assessed, handgrip strength, maximal inspiratory pressure (Pimax), and 6MWD were measured, and the one-repetition maximum (1RM) was determined for each of four exercises (bench press, lat pull down, leg extension, and leg press) performed on gymnasium equipment. Quality of life was assessed using the St. George Respiratory Questionnaire (SGRQ). We found statistically significant positive correlations between 6MWD and body weight (r = 0.32; p < 0.05), BDI (r = 0.50; p < 0.01), FEV, (r = 0.33; p < 0.05), PImax (r = 0.53; p < 0.01), and all values of 1RM. A statistically significant negative correlation was observed between 6MWD and dyspnea at the end of the 6-min walk test (r = -0.29; p < 0.05), as well as between 6MWD and the SGRQ activity domain (r = -0.45; p < 0.01) and impact domain (r = -0.34; p < 0.05) and total score (r = -0.40; p < 0.01). Multiple regression analysis selected body weight, BDI, Pimax, and lat pull down IRM as predictive factors for 6MWD (R-2 = 0.589).Conclusions: the results of this study showed the importance of the skeletal musculature of the thorax and upper limbs in submaximal exercise tolerance and could open new perspectives for training programs designed to improve functional activity in COPD patients.

Combined exercise training in asymptomatic elderly with controlled hypertension: Effects on functional capacity and cardiac diastolic function

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of three exercise programs on patients with chronic obstructive pulmonary disease

We compared the effect of three different exercise programs on patients with chronic obstructive pulmonary disease including strength training at 50_80% of one-repetition maximum (1-RM) (ST; N = 11), low-intensity general training (LGT; N = 13), or combined training groups (CT; N = 11). Body composition, muscle strength, treadmill endurance test (TEnd), 6-min walk test (6MWT), Saint George's Respiratory Questionnaire (SGRQ), and baseline dyspnea (BDI) were assessed prior to and after the training programs (12 weeks). The training modalities showed similar improvements (P > 0.05) in SGRQ-total (ST = 13 ± 14%; CT = 12 ± 14%; LGT = 11 ± 10%), BDI (ST = 1.8 ± 4; CT = 1.8 ± 3; LGT = 1 ± 2), 6MWT (ST = 43 ± 51 m; CT = 48 ± 50 m; LGT = 31 ± 75 m), and TEnd (ST = 11 ± 20 min; CT = 11 ± 11 min; LGT = 7 ± 5 min). In the ST and CT groups, an additional improvement in 1-RM values was shown (P < 0.05) compared to the LGT group (ST = 10 ± 6 to 57 ± 36 kg; CT = 6 ± 2 to 38 ± 16 kg; LGT = 1 ± 2 to 16 ± 12 kg). The addition of strength training to our current training program increased muscle strength; however, it produced no additional improvement in walking endurance, dyspnea or quality of life. A simple combined training program provides benefits without increasing the duration of the training sessions.

Perfil do nível de atividade física na vida diária de pacientes portadores de DPOC no Brasil

Objective: To evaluate characteristics of physical activities in daily life in COPD patients in Brazil, correlating those Characteristics with physiological variables. Methods: Physical activities in daily life were evaluated in 40 COPD patients (18 males; 66 +/- 8 years of age; FEV(1) = 46 +/- 16 % of predicted; body mass index = 27 +/- 6 kg/m(2)) and 30 healthy age- and gender-matched subjects, using a multiaxial accelerometer-based sensor for 12 h/day on two consecutive days. We also assessed maximal and functional exercise capacity, using the incremental exercise test and the six-minute walk test (6MWT), respectively; MIP and MEP; peripheral muscle force, using the one-repetition maximum test and the handgrip test; quality of life, using the Saint George's Respiratory Questionnaire (SGRQ); functional status, using the London Chest Activity of Daily Living questionnaire; and dyspnea sensation, using the Medical Research Council (MRC) scale. Results: Mean walking time/day was shorter for COPD patients than for the controls (55 +/- 33 vs. 80 +/- 28 min/day; p = 0.001), as movement intensity was lower (1.9 +/- 0.4 vs. 2.3 +/- 0.6 m/s(2); p = 0.004). The COPD patients also tended to spend more time seated (294 +/- 114 vs. 246 +/- 122 min/day, p = 0.08). Walking time/day correlated with the 6MWT (r = 0.42; p = 0.007) and maximal workload (r = 0.41; p = 0.009), as well as with age, MRC scale score and SGRQ activity domain score (-0.31 <= r <= -0.43; p <= 0.05 for all). Conclusions: This sample of Brazilian patients with COPD, although more active than those evaluated in studies conducted in Europe, were less active than were the controls. Walking time/day correlated only moderately with maximal and functional exercise capacity.

Lumbar muscles recruitment during resistance exercise for upper limbs

The aim of this study was to evaluate the EMG activity of lumbar multifidus (MU), longissimus thoracis (LT) and iliocostalis (IC) muscles during an upper limb resistance exercise (biceps curl). Ten healthy males performed maximal voluntary isometric contraction (MVC) of the trunk extensors, after this, the biceps curl exercise was executed at 25%, 30%, 35% and 40% one repetition maximum during 1 min, with 10 min rest between them. EMG root mean square (RMS) and median frequency (MFreq) were calculated for each lifting and lowering of the bar during the exercise bouts, to calculate slopes and intercepts. The results showed increases in the RMS and decreases in the MFreq slopes. RMS slopes were no different between muscles, indicating similar fatigue process along the exercise irrespective of the load level. MU and LT presented higher RMS irrespective of the load level, which can be related to the specific function during the standing position. on the other hand, IC and MU presented higher MFreq intercepts compared to LT, demonstrating possible differences in the muscle fiber conduction velocity of these muscles. These findings suggest that trunk muscles are differently activate during upper limb exercises, and the fatigue process affects the lumbar muscles similarly. (C) 2008 Elsevier Ltd. All rights reserved.

Electromyographic fatigue threshold of the biceps brachii muscle during dynamic contraction

The purpose of this study was to identify the Electromyographic Fatigue Threshold (EMG FT) of the biceps brachii muscle bilaterally during the elbow flexion in tests performed in different times: 30 second test, 1 minute test and fatiguing test, in concentric (CC) and eccentric (EC) phases. Nine healthy young men performed the elbow flexion with loads corresponding at 25%, 35% and 45% of the one repetition maximum (1-RM) in separate days. The results indicated that the test applied for the biceps brachii muscle during elbow flexion induced a progressive increment of EMG activity with time indicating muscle fatigue and allowed the identification of the EMG FT. The three tests presented no difference of EMG FT between CC and EC phases bilaterally.