Maximum Running Distance Research Articles

Utilização da distância total percorrida no teste específico de hoff como preditor da velocidade de limiar anaeróbio no futebol

OBJETIVO: Verificar a utilização da distância total percorrida no teste de Hoff como preditor da intensidade de limiar anaeróbio em jovens futebolistas. MÉTODOS: Para isso, 10 jovens jogadores de futebol (idade de 17 ± 1 ano e massa corporal de 64,3 ± 2,1 kg) participaram do estudo. Os sujeitos foram submetidos aos testes de 12 minutos, lactato mínimo para estimar a velocidade de limiar anaeróbio (vLAn) e ao teste de Hoff específico para o de futebol. O objetivo no teste de Hoff foi percorrer a máxima distância possível em 10 minutos de exercício conduzindo a bola de futebol em um circuito composto por dribles, saltos e corridas em direções diversas. RESULTADOS: A distância total percorrida no teste de 12 minutos foi 2.673,2 ± 64,7 m, a vLAn 11,6 ± 0,3 km.h-1 e a distância percorrida no Hoff 1.458,7 ± 49,6 m. A distância total percorrida no teste de Hoff não foi significativamente correlacionada com a vLAn (r = -0,20; P < 0,05) e com a distância percorrida no teste de 12 minutos (r = -0,15; P < 0,05). No entanto, a vLAn e a velocidade correspondente a 90% da velocidade média no teste de 12 minutos (12,0 ± 0,3 km.h-1) não foram diferentes significativamente e foram significativamente correlacionadas (r = 0,65; P < 0,05). CONCLUSÃO: Assim, pode-se concluir que a distância total percorrida no teste de Hoff não pode ser utilizada para predição da velocidade de limiar anaeróbia em futebolistas.

Skeletal muscle mitochondrial and metabolic responses to a high-fat diet in female rats bred for high and low aerobic capacity

Rats selected artificially to be low-capacity runners (LCR) possess a metabolic syndrome phenotype that is worsened by a high-fat diet (HFD), whereas rats selected to be high-capacity runners (HCR) are protected against HFD-induced obesity and insulin resistance. This study examined whether protection against, or susceptibility to, HFD-induced insulin resistance in the HCR-LCR strains is associated with contrasting metabolic adaptations in skeletal muscle. HCR and LCR rats (generation 20; n = 5-6; maximum running distance approximately 1800 m vs. approximately 350 m, respectively (p < 0.0001)) were divided into HFD (71.6% energy from fat) or normal chow (NC) (16.7% energy from fat) groups for 7 weeks (from 24 to 31 weeks of age). Skeletal muscle (red gastrocnemius) mitochondrial-fatty acid oxidation (FAO), mitochondrial-enzyme activity, mitochondrial-morphology, peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha), and peroxisome proliferator-activated receptor delta (PPARdelta) expression and insulin sensitivity (intraperitoneal glucose tolerance tests) were measured. The HFD caused increased adiposity and reduced insulin sensitivity only in the LCR and not the HCR strain. Isolated mitochondria from the HCR skeletal muscle displayed a 2-fold-higher rate of FAO on NC, but both groups increased FAO following HFD. PGC-1alpha mRNA expression and superoxide dismutase activity were significantly reduced with the HFD in the LCR rats, but not in the HCR rats. PPARdelta expression did not differ between strains or dietary conditions. These results do not provide a clear connection between protection of insulin sensitivity and HFD-induced adaptive changes in mitochondrial function or transcriptional responses but do not dismiss the possibility that elevated mitochondrial FAO in the HCR may play a protective role.

Enhancement of Exercise Capacity by Black Ginseng Extract in Rats

This study was carried out to investigate an enhancing effect of black ginseng extract (BGE) on exercise capacity in an endurance exercising animal model. Fifty Sprague-Dawley rats were assigned to 5 experimental groups including non-training control, training control, and 3 treated groups (BGE at doses of 75, 150 and 300 ㎎/㎏). The animals were treated with BGE for 6 weeks and their exercise ability in the maximal running distance test was determined using a treadmill every week. The blood lactic acid (LA) level and the activity of citrate synthase (CS) in the muscle were also measured after the exercise. The levels of glucose and glucose-6-phosphate (G-6-P) in the liver and muscle were determined using commercial assay kits. BGE treatments at the doses of 150 and 300 ㎎/㎏ significantly increased the exercise capacity compared with the non-training control or training control groups (P＜0.05). The level of blood LA was decreased but the activity of CS was increased by the treatment of BGE at the dose of 300 ㎎/㎏ compared with the training control group. The level of G-6-P in the liver was elevated by the treatment of BGE at the dose of 300 ㎎/㎏, compared to the training group. As compared with nontraining control group, the treatments of BGE increased the levels of glucose and G-6-P in the liver and soleus muscle of rats. These results indicate that BGE have a potential for promoting exercise capacity by increasing CS activity in the muscle and decreasing LA in the serum of rats. These results also suggested that BGE can be used as a candidate supplement of health food products for promoting endurance exercise capacity in human athletes.

Prevention of Overuse Injuries by a Concurrent Exercise Program in Subjects Exposed to an Increase in Training Load

Background It is unknown whether an exercise program can prevent overuse injuries in the lower extremity. An often encountered and important risk factor for the development of lower extremity overuse injuries is an abrupt increase in activity level. Hypothesis A preventive training program based on a literature review of intrinsic risk factors, and performed concurrent with an increase in physical activity, can reduce the incidence of overuse knee injuries and medial tibial stress syndrome, as well as increase running distance. Study Design Randomized controlled trial; Level of evidence, 1. Methods A total of 1020 soldiers aged 20.9 years (range, 19–26 years) undergoing 3 months of basic military training consecutively enrolled from December 2004 to December 2005. The prevention program consisted of an exercise program of 15 minutes’ duration 3 times a week, including 5 exercises for strength, flexibility, and coordination; the placebo program consisted of 5 exercises for the upper body. Results During the observation period, 223 subjects sustained an injury, with 50 and 48 of these fulfilling the study criteria for overuse knee injuries or medial tibial stress syndrome, respectively. There were no significant differences in incidence of injury between the prevention group and the placebo group (incidence, 0.22 vs 0.19; P = .162; relative risk = 1.05 [range, 0.98–1.11]). The soldiers in the prevention group had the greater improvement in running distance in 12-minute run tests (82 vs 43 m; P = .037). Conclusion An exercise program with an emphasis on muscular strengthening, coordination, and flexibility based on intrinsic risk factors identified through a literature review did not influence the risk of developing overuse knee injuries or medial tibial stress syndrome in subjects undergoing an increase in physical activity. The program increased maximal running distance in a 12-minute test.

Transcriptional basis for exercise limitation in male eNOS-knockout mice with age: heart failure and the fetal phenotype

Endothelium-derived nitric oxide (NO) is pivotal in regulating mitochondrial O(2) consumption (Vo(2)) and glucose uptake in mice. The aim of this study was to investigate the mechanism of age- and genotype-related exercise limitation in male endothelial NO synthase (eNOS)-knockout (KO, n = 16) and wild-type (WT, n = 19) mice. Treadmill testing was performed at 12, 14, 16, 18, and 21 mo of age. Vo(2), CO(2) production, respiratory exchange ratio, and maximal running distance were determined during treadmill running. There were good linear correlations for increase of speed with increase of Vo(2). The difference between KO and WT mice was not significant at 12 mo but was significant at 18 mo. Linear regression showed that KO mice consumed more O(2) at the same absolute and relative workloads, suggesting that Vo(2) was not inhibited by NO in KO mice. KO mice performed 30-50% less work than WT mice at each age (work = vertical distance x weight). In contrast to WT mice, the work performed by KO mice significantly decreased from 17 +/- 1.4 m.kg at 12 mo to 9.4 +/- 1.7 m.kg at 21 mo. Running distance was significantly decreased from 334 +/- 27 m at 12 mo to 178 +/- 38 m at 21 mo, and maximal Vo(2), CO(2) production, and respiratory exchange ratio per work unit were significantly higher in KO than in WT mice. Gene arrays showed evidence of a fetal phenotype in KO mice at 21 mo. In conclusion, age- and genotype-related exercise limitations in maximal work performed and maximal running distance in male eNOS-KO mice indicated that fetal phenotype and age were related to onset of heart failure.

Biochemical evaluation of antioxidant function after a controlled optimum physical exercise among adolescents

Sensible physical exercise is shown to prevent certain neurovascular problems. However, in recent times, non-traumatic sudden death in young athletes has been observed and the incidence level is always very disturbing, because of the spontaneous nature of the occurrence. It most commonly occurs fivefold more in male than female athletes. Although it is believed that congenital cardiovascular disease is the leading cause of non-traumatic sudden athletic death, however, sudden physical alteration in the biochemical composition of the body system may, at least in part, play an important role. The role of antioxidants in the general maintenance of homeostasis has already been established. In this study, total antioxidant function in athletes subjected to controlled physical exercise was evaluated to determine the extent to which intensive physical exercise could alter the health conditions if adequate actions are not taken to adjust the biochemistry of the body system. Ten male field-track athletes were exercised using a fixed workload treadmill test. Blood samples were drawn before and after the exercise. The subjects exercised almost to their maximum running distance at a higher "fatigue" workload for a maximum of 20 min each day for five days. The lymphocytes' total antioxidant function was measured by addition of a peroxide (oxidative stress) to complete the medium. Lymphocyte growth response with peroxide was reported as a percentile of growth responses from a reference range of apparently healthy individuals. Values below the 25th percentile indicate a deficient antioxidant function. The results showed that although vitamin B3, B6, and B12 requirements were normal, there was a consistent low value in the total percentile of vitamins B1 (<79%), B2 (<54%), folate (<33%, and biotin (<70%). There was a dramatic decrease in the mean values of antioxidant function (38.1%) in all the subjects as opposed to the reference range of <75%. Overall reduction antioxidant function indicates decreased ability to resist oxidative stress, or an increased oxidant load, suggesting increased antioxidant utilization and/or cellular "tear and wear" scenario. It is therefore suggested that after intensive physical exercise, antioxidant functions should be monitored and supplemented whenever necessary to maintain the integrity of the cellular function.

Effect of RGH-2981, new peripheral circulation improver, and pentoxifylline on maximal running distance of femoral artery occluded mice

Effect of RGH-2981, new peripheral circulation improver, and pentoxifylline on maximal running distance of femoral artery occluded mice