Health and fitness benefits of a resistance training intervention performed in the workplace.

This study examined the effects of a workplace-based resistance training intervention on different health-, fitness-, and work-related measures in untrained men (bus drivers). The subjects were recruited from a bus company and divided into a training (n = 48) and control (n = 48) groups after initial prescreening. The training group performed a 24-week resistance training program, whereas the control group maintained their normal daily activities. Each group was assessed for body composition, blood pressure (BP), pain incidence, muscular endurance, and flexibility before and after the 24-week period. Work absenteeism was also recorded during this period and after a 12-week follow-up phase. In general, no body composition changes were identified in either group. In the training group, a significant reduction in BP and pain incidence, along with improvements in muscle endurance and flexibility were seen after 24 weeks (p < 0.05). There were no changes in these parameters in the control group, and the between-group differences were all significant (p < 0.05). A reduction in worker absenteeism rate was also noted in the training (vs. control) group during both the interventional and follow-up periods (p < 0.05). In conclusion, it was found that a periodized resistance training intervention performed within the workplace improved different aspects of health and fitness in untrained men, thereby potentially providing other work-related benefits. Thus, both employers and employees may benefit from the setup, promotion, and support of a work-based physical activity program involving resistance training.

Resistance Exercise Intensity Does Not Influence Neurotrophic Factors Response in Equated Volume Schemes.

The aim of the present study was to evaluate the effects of 2 different intensities of resistance training (RT) bouts, performed with the equated total load lifted (TLL), on the acute responses of neurotrophic factors (NFs) (brain-derived neurotrophic factor [BDNF]; and nerve growth factor [NGF]), as well as on metabolic (lactate concentration) and hormonal (salivary cortisol concentration) responses. Thirty participants (males, 22.8 ± 2.3 years old, 177 ± 6.8 cm, 75.5 ± 7.9 kg, n = 15; and females, 22.2 ± 1.7 years, 163.7 ± 6.5 cm, 57 ± 7.6 kg, n = 15) performed 2 separate acute RT bouts with one week between trials. One bout consisted of 4 sets of 5 submaximal repetitions at 70% of 1RM and the other of 4 sets of 10 submaximal repetitions at 35% of 1RM for each exercise. Both RT bouts were conducted using the bench press and squat exercises. The TLL in each bout (determined by sets x repetitions x load [kg]) was equated. Serum BDNF, serum NGF, salivary cortisol, and blood lactate concentration were determined pre- and post-RT. No significant pre- to post-exercise increase in neurotrophic factors (p > 0.05; BDNF; effect size = 0.46 and NGF; effect size = 0.48) was observed for either of the RT bouts. A similar increase in blood lactate concentration was observed pre- to post-exercise for both RT bouts (p < 0.05). Cortisol increased similarly for both RT bouts, when compared to the resting day condition (p < 0.05). In conclusion, the results suggest that, despite differences in RT schemes, a similar acute neurotrophic, metabolic and hormonal response was observed when the TLL is equated.

Acute effect of different warm-up interventions on neuromuscular performance of recreational soccer players / Efeito agudo de diferentes intervenções de aquecimento pré-exercício sobre o desempenho neuromuscular de jogadores amadores de futebol

Pre-exercises interventions are frequently implemented in order to maximize athletic performance. In this sense, the aim of this study was to evaluated the effect of three distinct pre-exercise interventions on acute neuromuscular performance in recreational soccer players: 1) parallel squat; 2) static stretching; and 3) ballistic stretching. After all interventions, participants performed a flexibility evaluation (sit-and-reach-test), followed by a squat jump, a counter-movement jump and a 30 meter-sprint test. A one-way analysis of variance revealed: a) a significant decrease in jumping performance was induced by both Stretching conditions when compared to the parallel squat intervention; b) a significant increase in lower limb flexibility after both stretching interventions when compared to parallel squat. In conclusion, it is suggested that a pre-exercise intervention comprised of stretching exercises acutely increase flexibility, while may interfere in jump performance in recreational athletes...(AU)

Intervenções pré-exercício são frequentemente adotadas para maximizar o desempenho atlético. Nesse sentido, o objetivo deste estudo foi avaliar o efeito de três diferentes intervenções pré- exercício sobre o desempenho neuromuscular de jogadores de futebol amadores: 1) agachamento paralelo, 2) alongamento estático e 3) alongamento balístico. Após as intervenções, os participantes realizaram a avaliação de flexibilidade (teste de sentar e alcançar) e, em seguida, o salto com agachamento, o salto com contramovimento e o teste de velocidade de 30 metros. Os resultados da ANOVA one-way revelaram: a) redução significante no desempenho do salto para ambas às condições de alongamento quando comparadas ao agachamento paralelo e b) aumento significante da flexibilidade dos membros inferiores após ambas às intervenções de alongamento em comparação ao achamento paralelo. Em conclusão, sugere-se que as intervenções pré-exercício compostas de exercícios de alongamento aumentam agudamente a flexibilidade, paralelamente, podendo prejudicar o desempenho de saltos de atletas amadores...(AU)

Suplementação aguda de citrato de sódio não maximiza desempenho de força / Sodium citrate supplementation does not enhance strength performance

O objetivo do presente estudo foi avaliar o efeito da suplementação aguda de citrato de sódio (citrato-Na) sobre o desempenho de repetições máximas (RMs) em exercícios de força. Quatorze jovens saudáveis, fisicamente ativos, foram divididos em duas condições experimentais (placebo [PLA] ou citrato-Na [0,5g.kg-1]), seguindo o delineamento duplo-cego. O teste de RMs foi realizado em 2 momentos (pré e pós suplementação ­ 120 minutos), utilizando 2 exercícios: supino e agachamento. A concentração de lactato sanguíneo foi determinada antes e após cada teste de RMs. O número de RMs não foi diferente entre as condições experimentais (citrato-Na e PLA; p>0,05), tanto para primeiro quanto para segundo teste de RMs. Houve aumento similar na concentração de lactato, após a primeira série de cada exercício (pré-suplementação), para ambos as condições (citrato-Na e PLA; p<0,05). Após o protocolo de suplementação, a concentração de lactato também apresentou aumento em ambos as condições (p<0,05), com maior magnitude para a condição citrato-Na (p<0,05). Estes achados sugerem que a suplementação aguda de citrato-Na não exerceu efeito ergogênico sobre o desempenho de força, mais especificamente, em relação ao número de RMs.(AU)

The aim of this study was to evaluate the effect of acute sodium citrate supplementation (citrate-Na) on the maximum repetitions (RMs) performance in strength exercises. Fourteen healthy young, physically active, were divided into two experimental conditions (placebo [PLA] or citrate-Na [0,5g.kg-1]), following a double-blind design. The RMs test was conducted in two moments (pre and post supplementation - 120 minutes) using 2 exercises: bench press and squat. The blood lactate concentration was determined before and after each RMs test. The number of RMs did not differ between the experimental conditions (citrate-Na and PLA; p> 0.05) for both first and for the second tests. There was a similar increase in lactate concentration after the first set of each exercise (pre-supplementation), for both conditions (and PLA-Na citrate; p <0.05). After supplementation protocol, the lactate concentration also increased in both the conditions (p <0.05) with a greater magnitude for citrate-Na condition (p <0.05). These findings suggest that acute citrate-Na supplementation did not exert an ergogenic effect on strength performance, more especifically, related to the number of RMs.(AU)

Efeito da intensidade do exercício de força sobre a ocorrência da dor muscular de início tardio / Effect of resistance exercise intensity on delayed onset muscle soreness

O objetivo do presente estudo foi verificar o efeito da intensidade do exercício de força sobre a percepção de dor muscular de início tardio (DMIT). A fim de investigar a hipótese que a intensidade determina o nível de DMIT, foram selecionados 40 homens saudáveis, iniciantes no treinamento de força, que, posteriormente, foram submetidos a duas sessões de treinamento realizadas com intensidades distintas (50%-1RM (n=20) e 75%-1RM (n=20)). A DMIT foi analisada por meio da escala analógica visual, 24, 48 e 72h após cada sessão de treinamento. A DMIT apresentou aumento significante em ambas as sessões (50%-1RM e 75%-1RM) (p<0,05), atingindo o pico em 48h (p<0,05). Entretanto, a DMIT não apresentou diferença entre as sessões (50%-1RM vs. 75%-1RM) (p>0,05). Os resultados desse estudo sugerem que a intensidade não parece ser um fator determinante para a magnitude da DMIT, quando o volume total de carga levantada na sessão de treinamento é equalizado.

The aim of the study was to assess the effect of resistance exercise intensity on the perceived DOMS. In order to investigate the hypothesis that the intensity determines the magnitude of DOMS, 40 healthy, untrained men were subjected to two bouts of resistance exercise performed at different intensities (50%-1RM (n=20) and 75%-1RM (n=20)). DOMS was assessed using visual analogue scale, 24, 48 and 72 hours after each training bout. DOMS increased after both exercise bouts (50%-1RM and 75%-1RM) (p<0.05), peaking at 48 hours (p<0.05). However, DOMS did not differ between exercise sessions (50%-1RM and 75%-1RM) (p>0.05). The results suggested that the intensity does not seem to influence the magnitude of DOMS when the total volume of load lifted during the exercise bout is equalized.