Effects of Strength Training on Running Economy

The objective of this study was to compare the effect of different strength training protocols added to endurance training on running economy (RE). Sixteen well-trained runners (27.4 +/- 4.4 years; 62.7 +/- 4.3 kg; 166.1 +/- 5.0 cm), were randomized into two groups: explosive strength training (EST) (n = 9) and heavy weight strength training (HWT) (n = 7) group. They performed the following tests before and after 4 weeks of training: 1) incremental treadmill test to exhaustion to determine of peak oxygen uptake and the velocity corresponding to 3.5 mM of blood lactate concentration; 2) submaximal constant-intensity test to determine RE; 3) maximal countermovernent jump test and; 4) one repetition maximal strength test in leg press. After the training period, there was an improvement in RE only in the HWT group (HWT = 47.3 +/- 6.8 vs. 44.3 +/- 4.9 ml.kg(-1) -min(-1); EST = 46.4 +/- 4.1 vs. 45.5 +/- 4.1 ml.kg(-1) .min(-1)). In conclusion, a short period of traditional strength training can improve RE in well-trained runners, but this improvement can be dependent on the strength training characteristics. When comparing to explosive training performed in the same equipment, heavy weight training seems to be more efficient for the improvement of RE.

Exercise-induced muscle damage and running economy in humans

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (15-30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VOax). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (90% VOax). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE. © 2013 Cláudio de Oliveira Assumpção et al.

Interval training at 95% and 100% of the velocity at VO2 max: effects on aerobic physiological indexes and running performance

The objective of this study was to analyze the effect of two different high-intensity interval training (HIT) programs on selected aerobic physiological indices and 1500 and 5000 m running performance in well-trained runners. The following tests were completed (n = 17): (i) incremental treadmill test to determine maximal oxygen uptake (VO2max), running velocity associated with VO2 max (VVO2max), and the velocity corresponding to 3.5 mmol/L of blood lactate concentration (vOBLA); (ii) submaximal constant-intensity test to determine running economy (RE); and (iii) 1500 and 5000 m time trials on a 400 m track. Runners were then randomized into 95% vVO(2max) or 100% vVO(2max) groups, and undertook a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO(2max), respectively) and 4 submaximal run sessions per week. Runners were retested on all parameters at the completion of the training program. The VO2 max values were not different after training for both groups. There was a significant increase in post-training vVO(2 max), RE, and 1500 in running performance in the 100% vVO(2 max) group. The vOBLA and 5000 m running performance were significantly higher after the training period for both groups. We conclude that vOBLA and 5000 m running performance can be significantly improved in well-trained runners using a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO(2max)) and 4 submaximal run sessions per week. However, the improvement in vVO(2 max), RE, and 1500 in running performance seems to be dependent on the HIT program at 100% vVO(2 max).

Índices fisiológicos associados com a performance aeróbia em corredores de endurance: efeitos da duração da prova

O objetivo deste estudo foi analisar a validade do consumo máximo de oxigênio (VO2max), da velocidade correspondente ao VO2max (vVO2max), do tempo de exaustão na vVO2max (Tlim), da economia de corrida (EC) e do limiar anaeróbio (LAn) para a predição da performance de atletas de endurance. Quatorze corredores de endurance (33,4 ± 4,4 anos; 62,7 ± 4,3kg; 166,1 ± 5,0cm; VO2max = 60,4 ± 5,9ml.kg-1.min-1) realizaram os seguintes testes: a) competição simulada nas distâncias de 1.500 e 5.000m. e; b) testes de laboratório para a determinação do VO2max, vVO2max, EC, LAn e Tlim na intensidades de 100% vVO2max. As velocidades (km/h) da vVO2max (18,7 ± 0,8), LAn (17,3 ± 1,1) v1.500m (19,9 ± 0,8) e v5.000m (17,9 ± 0,9) foram significantemente diferentes. A regressão múltipla stepwise revelou que o LAn foi o único preditor da performance da v5.000m, explicando 50% da variação desta performance. Para a v1.500m, o Tlim e a vVO2max explicaram 88% da variação da performance. Com base em nossos resultados, pode-se concluir que a validade dos índices fisiológicos (VO2max, vVO2max, Tlim, EC e LAn), para a predição da performance aeróbia de atletas de endurance, é dependente da distância da prova (1.500 x 5.000m) analisada.

Variáveis fisiológicas e neuromusculares associadas com a performance aeróbia em corredores de endurance: efeitos da distância da prova

O objetivo deste estudo foi analisar a validade do consumo máximo de oxigênio (VO2max), velocidade associada ao VO2max (vVO2max), tempo de exaustão na vVO2max (Tlim), limiar anaeróbio (LAn), economia de corrida (EC) e força explosiva (FE) para predizer a performance aeróbia de corredores de endurance nas distâncias de 1.500m, 5.000m e 10.000m. Participaram deste estudo 11 corredores de endurance moderadamente treinados (28,36 ± 6,47 anos) que realizaram os seguintes testes: provas simuladas em uma pista de 400m em diferentes dias, nas distâncias de 10.000m, 5.000m e 1.500m; teste incremental máximo para determinar os índices VO2max, vVO2max, e LAn; um teste submáximo de carga constante para determinar a EC, seguido por um teste máximo também de carga constante a 100% da vVO2max para determinar o Tlim; e um teste de salto vertical para determinar a FE. de acordo com a análise de regressão múltipla, a vVO2max utilizada de forma isolada explicou 57% da variação de performance na prova de 1.500m. No entanto, quando o Tlim, a FE e a vVO2max foram analisados em conjunto, a explicação para a performance nessa prova foi de 88%. Nos 5.000m, o Tlim, a vVO2max e o LAn responderam por 88% da variação de performance (p < 0,05). Diferentemente, na prova de 10.000m, o LAn foi a única variável que apresentou capacidade de predição de performance. em conclusão, a predição da performance aeróbia de corredores moderadamente treinados por meio de variáveis fisiológicas e neuromusculares é dependente da distância da prova (1.500m, 5.000m e 10.000m)

Relação da potência aeróbica máxima e da força muscular com a economia de corrida em atletas de endurance

The objective of this study was to analyze the relationship of maximal aerobic power and the muscular strength (maximal isotonic strength and vertical jump explosive power) with the running economy (RE) in endurance athletes. Twenty-six male runners (27.9 ± 6.4 years; 62.7 ± 4.3 kg; 168.6 ± 6.1 cm; 6.6 ± 3.1% of body fat) performed in different days the following tests: a) incremental test to determine the maximal oxygen uptake (V̇O2max) and the intensity corresponding to the V̇O2max (IV̇O2max); b) constant-velocity treadmill run to determine RE; c) 1-RM test in the leg press and; d) maximal vertical jump test (VJ). V̇O2max (63.8 ± 8.3 ml/kg/min) was significantly correlated (r = 0.63; p < 0.05) with RE (48.0 ± 6.6 ml/kg/min). However, the IV̇O2max (18.7 ± 1.1 km/h), the maximal isotonic strength (230.3 ± 41.2 kg) and the VJ (30.8 ± 3.8 cm) were not significantly correlated with RE. One concludes that the maximal aerobic power can explain in part the inter-individual RE variability in endurance athletes. However, maximal isotonic strength and explosive strength seem not to be associated with RE values observed in this group of athletes.

Efeitos do treinamento de caminhada com restrição do fluxo sanguíneo sobre economia de corrida em indivíduos ativos

Pós-graduação em Desenvolvimento Humano e Tecnologias - IBRC

Efeitos do treinamento de caminhada em declive sobre índices de aptidão aeróbia

Pós-graduação em Desenvolvimento Humano e Tecnologias - IBRC

Efeitos do dano muscular sobre indicadores neuromusculares e de aptidão aeróbia

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

Comparação entre a recuperação da economia de corrida e força muscular medida por diferentes métodos após o dano muscular

The goal of the present study was to investigate possible differences towards strenght recovery measured by different methods and running economy (RE), after one session of downhill running (DR), in order to induce muscle damage (MD). Our hypothesis is that the strenght recovery measured by jumps is more alike RE markers, due to the measures' specificity. Ten male subjects, ages 18 to 30, apparently healthy, without any experience with strenght training at least 6 months before the tests took place in this study. After going to the lab twice (to familiarize themselves with the protocols, and determine their maximum oxygen consumption/running speeds), they went to the lab five times in the following week, in order to collect all the variables before, immediately after, and 24, 48, 72 and 96 hours in. The variables obtained were: stride frequency (SF), stride lenght (SL), oxygen volume (VO2), carbon dioxide volume (VCO2), ventilation (VE), lactate blood concentration ([Lac]), isometric peak torque (IPT), subjective pain perception (SPP), effort perception (EP), medial-portion circumference (CIR), knee movement extent (EXT), torque development rate (TDR), counter movement jump and squat jump height (HCM and HS), strenght development rate of both jumps (SDCM and SDS), and maximum soil strenght reaction (SRCM and SRS). Changes over time in all variables were verified by one way variancy analysis. Differences between the strenght measures were verified by two way variancy analysis. When significant effects were verified, Tuckey's post-hoc were applied. The significancy level taken on this study was p < 0,05. Of all indirect muscle damage markers, IPT, SPP and TDR were the only ones in which ocurred significant changes. We couldn't find the moments where this happened for TDR with the post-hoc used. On RE markers, VO2, [Lac] and VE suffered significant effects over time. About the jumps variables, only SDCM and HCM presented significant...

Antipanic procedures reduce the strychnine-facilitated wild running of rats

Wild running (WR) behavior of rats seen in response to intense acoustic stimulation of audiogenic seizure-paradigm is very similar to the panic flight and can be facilitated by subconvulsive doses of strychnine. The present work aimed to test whether antipanic procedures, such as dorsal periaqueductal gray (dPAG) lesion and imipramine treatments, affect the strychnine-facilitated WR. In study 1, six Wistar male adult rats with electrolytic lesion of dPAG had their WR completely blocked, whereas it was facilitated in 50% of sham-lesioned control rats by a dose of 0.5 mg/kg of strychnine administered intraperitoneal. This effect was not reproduced with a higher strychnine dose (1.0 mg/kg). In study 2, the effects of imipramine were investigated by testing 36 rats under a dose of strychnine that induces WR in 50% of subjects. They were assigned into three experimental groups: imipramine treatments of 5.0 and 10.0 mg/kg, and infusions of saline. All these treatments were subchronical with three intraperitoneal injections within 24h. Imipramine (10.0mg/kg) reduced the incidence of WR in comparison to the saline results. It is concluded that strychnine-facilitated WR is reduced by antipanic procedures and, therefore, can be viewed as a manifestation closely related to panic. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Correlation between the fighting rates of REM sleep-deprived rats and susceptibility to the 'wild running' of audiogenic seizures

Sleep-deprived rats exhibit defensive fighting as well as explosive flights very similar to the wild-running of audiogenic seizures. In order to determine why sleep deprivation is a common factor that facilitates both panic and convulsive manifestations, the present study was undertaken to investigate whether rats that display sleep deprivation-induced fighting (SDIF) are the same as those that are susceptible to audiogenic wild-running (WR). Twenty-eight male adult Wistar rats were divided into two groups assigned to two e-sleep deprivation for 5 days and had their SDIF evaluated in social experimental schemes. In the first, 18 subjects were submitted to REM grouping. After 1 week for recovery, their susceptibility to WR was tested in an acoustic stimulation trial ( 104 dB, 200 Hz, 60 S). Rats that did not present WR received a lactate infusion and were tested again by acoustic stimulation 40 min later. In the second experimental scheme, 10 subjects were initially evaluated for WR susceptibility and the number of SDIF was recorded in social grouping after I week. Three categories of WR-susceptibility were determined: WR-sensitive rats, intermediate WR-sensitive rats and WR-insensitive rats. T'he number of SDIF in each category was significantly different and there was a high positive correlation (r=0.89; Spearman test) between the number of SDIF and the level of WR-susceptibility. We conclude that the reasons why sleep deprivation exerts facilitatory effects on both panic and convulsive manifestations are due to overlappings of neural pathways responsible for both behavioral patterns and for the property of sleep deprivation to increase neuronal excitability. (C) 2002 Elsevier B.V. B.V. All rights reserved.

On the optimum parameters of a device for harvesting energy from running and walking

This paper investigates the feasibility of using an energy harvesting device tuned such that its natural frequency coincides with higher harmonics of the input to capture energy from walking or running human motion more efficiently. The paper starts by reviewing the concept of a linear resonant generator for a tonal frequency input and then derives an expression for the power harvested for an input with several harmonics. The amount of power harvested is estimated numerically using measured data from human subjects. Assuming that the input is periodic, the signal is reconstructed using a Fourier series before being used in the simulation. It is found that although the power output depends on the input frequency, the choice of tuning the natural frequency of the device to coincide with a particular higher harmonic is restricted by the amount of damping that is needed to maximize the amount of power harvested, as well as to comply with the size limit of the device. It is also found that it is not feasible to tune the device to match the first few harmonics when the size of the device is small, because a large amount of damping is required to limit the motion of the mass.

Calcaneal Tendon Regions Exhibit Different MMP-2 Activation After Vertical Jumping and Treadmill Running

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

Effect of soccer training on the running speed and the blood lactate concentration at the lactate minimum test

Tegtbur et al. [23] devised a new method able to estimate the intensity at maximal lactate steady state termed lactate minimum test. According to Billat et al. [7], no studies have yet been published on the affect of training on highest blood lactate concentration that can be maintained over time without continual blood lactate accumulation. Therefore, the aim of the present study was to verify the effect of soccer training on the running speed and the blood lactate concentration (BLC) at the lactate minimum test (Lac(min)). Thirteen Brazilian male professional soccer players, all members of the same team playing at National level, volunteered for this study. Measurements were carried out before (pre) and after (post) eight weeks of soccer training. The Lac(min) test was adapted to the procedures reported by Tegtbur et al. [23]. The running speed at the Lac(min) test was taken when the gradient of the line was zero. Differences in running speed and blood lactate concentration at the Lac(min) test before (pre) and after (post) the training program were evaluated by Student's paired t-test. The training program increased the running speed at the Lac(min) test (14.94 +/- 0.21 vs. 15.44 +/- 0.42* km(.)h(-1)) and the blood lactate concentration (5.11 +/- 2.31 vs. 6.93 +/- 1.33* mmol(.)L(-1)). The enhance in the blood lactate concentration may be explained by an increase in the lactate/H+ transport capacity of human skeletal muscle verified by other authors.