Are early and late rate of force development differently influenced by fast-velocity resistance training?

This study examined the effect of fast-velocity concentric isokinetic resistance training (FV) on the rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising muscle force. Nine men participated in a 6-week resistance training intervention for the lower body, and nine matched subjects participated as controls (CON). During concentric isokinetic (180°s-1) knee extension training, subjects were instructed to do each contraction 'as fast and forcefully as possible'. Maximal muscle strength (MVC) and RFD (0-10, 0-20, ..., 0-250 ms from the onset of contraction) were measured during maximal voluntary isometric contraction of the knee extensors (KE). There were no significant changes in MVC of KE in both groups after intervention (FV = 314·2 ± 101·1 versus 338·7 ± 88·0 N{bullet operator}m, P>0·05; CON = 293·3 ± 94·8 versus 280·0 ± 72·2 N{bullet operator}m, P>0·05). The RFD increased 39-71% at time intervals up to 90 ms from the onset of the contraction (P<0·05), whereas no change occurred at later time intervals. Similarly, relative RFD (i.e.%MVC{bullet operator}s-1) (RFDr) increased 33-56% at time intervals up to 70 ms from the onset of the contraction (P<0·05). It can be concluded that a short period of resistance training performed with concentric fast-velocity isokinetic muscle contractions is able to enhance RFD and RFDr obtained at the early phase of rising muscle force. © 2013 The Authors Clinical Physiology and Functional Imaging © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Improvement of heart rate variability after exercise training and its predictors in COPD

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Respiratory muscular strength decrease in children with mylomeningocele

Study Design. Case-control study.Objective. To evaluate respiratory muscle force in children with myelomeningocele. Summary of Background Data. Myelomeningocele is a common spinal cord malformation with limitations linked to central nervous system lesions and abnormalities in respiratory movements. Despite this, little attention has been given to evaluating respiratory muscle force in these patients.Methods. Children with myelomeningocele aged between 4 and 14 years ( myelomeningocele group; MG, n = 20) were studied and compared with healthy children ( control group; CG, n = 20) matched for age and gender. Respiratory muscular force was evaluated by maximum inspiratory ( Pimax) and expiratory ( Pemax) pressures.Results. Groups were similar for age [ CG = 8 ( 6 - 13) = MG = 8 ( 4 - 14), P > 0.05]; gender, and body mass index [ CG = 17.4 ( 14.1 - 24.7) x MG = 19.2 ( 12.6 - 31.9), P > 0.05]. The lumbosacral region was predominantly affected ( 45%). Maximum respiratory pressures were significantly higher in CG than MG ( Pimax = CG: similar to 83 +/- 21.75 > MG: -54.1 +/- 23.66; P < 0.001 and Pemax = CG: + 87.4 +/- 26.28 > MG: + 64.6 +/- 26.97; P = 0.01). Patients with upper spinal lesion ( UL) had lower maximum respiratory pressure values than those with lower spinal lesion ( LL), [Pimax ( UL = - 38.33 +/- 11.20 cm H2O x LL = - 60.85 +/- 24.62 cm H2O), P < 0.041 and Pemax ( UL = + 48 +/- 20.82 cm H2O x LL + 71.71 +/- 26.73 cm H2O), P = 0.067]).Conclusion. Children with myelomeningocele at the ages studied presented reduced respiratory muscle force with more compromise in upper spinal lesion.

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.

Efeito agudo do alongamento estático na força muscular de mulheres idosas

O objetivo deste estudo foi investigar, em mulheres idosas, o efeito agudo do alongamento estático sobre a taxa de desenvolvimento de força pico (TDFP) e contração voluntária máxima (CVM). A amostra foi composta por 10 mulheres idosas (idade 68,5 ± 7,0 anos; peso 70,9 ± 8,1 kg; estatura 159,4 ± 6,0 cm; índice de massa corporal 28,0 ± 3,8 kg/m²). A TDFP e a CVM foram testadas no exercício Leg Press, antes e após as condições controle ou alongamento (três séries de 30 segundos de alongamento estático do quadríceps femoral), em dois dias diferentes (24 horas de intervalo). A TDFP foi determinada como a inclinação mais íngreme da curva, calculada dentro da janela regular de 20 ms (∆Força/∆Tempo), para os primeiros 200 ms após o início da força muscular. A CVM foi determinada como o maior ponto registrado na tentativa. em cada dia, apenas uma condição foi testada e a ordem de emprego para cada condição foi determinada aleatoriamente. A intensidade do alongamento foi determinada pelo limiar de dor muscular. Quatro avaliações pós-condições (pós-tratamento; 10; 20 e 30 minutos) foram realizadas para acompanhar o comportamento da força muscular. A ANCOVA 2x5, seguida do teste post-hoc de Scheffé, não mostrou interações, condição vs. momento, significativas (P > 0,05) para a TDFP e CVM. em conclusão, séries agudas de alongamento estático para o quadríceps femoral não afetam a capacidade de produzir força muscular rapidamente e máxima de mulheres idosas.

Muscular coactivation (CA) around the knee reduces power production in elderly women

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dynamic and isometric protocols of knee extension: Effect of fatigue on the EMG signal

The objective of this study was to analyze the electromyographic (EMG) signal behavior of rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL) and biceps femoris (caput longum) (BFCL) from nine women during fatiguing dynamic and isometric knee extensions tests and to determine their EMGFT (Electromyographic Fatigue Threshold). Surface electrodes, biological signal acquisition module, analogical-digital converter board and specific software were used. The RMS (Root Mean Square) values obtained from concentric phase (80 to 30 degrees) of the dynamic knee extension andfrom isometric contraction were correlated with time on each load by linear regression analysis. The respective slopes were correlated with the correspondent load to determine the EMGFT. Force (Kgf) and median frequency - MF (Hz) obtained during MIVC (Maximal Isometric Voluntary Contraction) performed before and after the fatiguing tests were calculated in Matlab environment. The results demonstrated that the endurance time decreases with higher loads the EMG amplitude increase with time and was greater at higher loads, between muscles in dynamic exercise the RF and VL showed higher slopes, and in isometric exercise the VL showed the same behavior The EMGFT values were similar in both exercises; the force values predominantly decreased after fatiguing tests; however the MF only decreased after some loads. The protocols proposed allowed standardizing protocols at least to induce the fatigue process and to determine the EMGFT as an endurance indicative, which may be used to evaluate the effectiveness of rehabilitative or training interventions indicated to reduce muscle weakness and fatigue.

Subjective, cardiovascular and EMG spectral recovery after lumbar extension exhaustion test

The purpose of this randomized study was to evaluate EMG spectral, subjective and cardiovascular recovery parameters after isometric lumbar extension contractions. Ten healthy women performed isometric lumbar extensions until exhaustion with 5%, 10%, 15% and 20% of maximal voluntary isometric contraction on 4 different days (random order). One baseline five second contraction was performed before the fatiguing task which was followed by eight submaximal five second extension contractions (until 20 minutes after the end of the fatiguing task) at the same intensity as the trial to evaluate muscle recovery. EMG (Median Frequency, Peak Power, Peak Power Frequency, Total Power and Zero-crossing Rate) and cardiovascular variables did not demonstrate any statistical difference between the 5-second contractions (p > 0.05) performed before and after the fatiguing task, showing a quick EMG recovery. However, the data analysis showed that the perceived effort variable had not recovered even 10 minutes after the fatigue contraction (p < 0.05). Our results represent a data basis for future comparisons and since subjective felling can affect performance, this study shows the importance of its analysis, since the subjective effort rate was not fully recovered after 10 minutes the end of the exhaustion contraction. © 2008 IOS Press. All rights reserved.

Influence of exercise order on upper body maximum and submaximal strength gains in trained men

The purpose of this study was to investigate the influence of exercise order on one-repetition maximum (1-RM) and ten-repetition maximum (10-RM) strength gains after 6 weeks of resistance training (RT) in trained men. Sixteen men were randomly assigned into two groups based on the order of exercises performed during training sessions: a group that performed large muscle group exercises first and progressed to small muscle group exercises (LG-SM); while a second group performed the opposite sequence and started with small muscle group exercises and progressed to large muscle group exercises (SM-LG). Four sessions of RT were conducted per week; all exercises were performed for three sets of 8-12 repetitions with 1-min rest intervals between sets. Maximal and submaximal strength were assessed at baseline and after 6 weeks of RT with 1-RM and 10-RM testing for the bench press (BP), lat pulldown (LPD), triceps pulley extension (TE) and biceps curl (BC), respectively. Two-way ANOVA for the 1-RM and 10-RM tests indicated a significant group x time interaction. The 1-RM values significantly increased for all exercises in both groups (P<0.05), but were not significantly different between groups. However, effect size (ES) data indicated that the LG-SM group exhibited a greater magnitude of gains (1-RM and 10-RM) for the BP and LPD exercises. Conversely, ES indicated that the SM-LG group exhibited a greater magnitude of gains (1-RM and 10-RM) for the TE and BC exercises. In conclusion, the results suggest that upper body movements should be prioritized and performed according to individual needs to maximize maximal and submaximal strength. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Caracterização do perfil de atividade física na vida diária de pacientes portadores de DPOC do Brasil e comparação com pacientes da Áustria

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de dois programas de treinamento físico sobre a função autonômica cardíaca e nível de atividade física na vida diária em pacientes portadores de doença pulmonar obstrutiva crônica (DPOC)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito agudo do alongamento estatístico na curva força-tempo isométrica de idosas em exercício mono e multiarticular

Pós-graduação em Ciências da Motricidade - IBRC

Função e massa muscular em pacientes com doença pulmonar obstrutiva crônica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da qualidade de vida, força muscular respiratória e distância percorrida no teste de caminhada de seis minutos em pacientes com hipertensão arterial pulmonar sob tratamento farmacológico específico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da suplementação de taurina ou flavonóides de cacau associado à achocolatado sobre a composição corporal, metabolismo de carboidratos e proteinas, desempenho fisico, dano muscular e estresse oxidativo em atletas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)