The achievement of high performance levels in a complex structured sport such as karate is determined by the competitor’s physical fitness, fighting technique, tactics and mental state. This study aimed to identify the most important determinants of top-level performance in karate. Methods: The participants were 32 karate competitors (12 women and 20 men) aged 18–25 years. A series of tests measuring 11 anthropometric features was undertaken twice during a year, separated by a 6-week interval during a training camp at the Olympic Preparation Center in Walcz, Poland. Motor skills were measured with strength, speed, endurance, flexibility and reaction time tests. Special motor fitness was assessed with tests of karate technical skills. The results were subject to statistical analysis using multiple stepwise regression of the Polish Karate Federation ranking points as the dependent variable. Results: The multiple regression analysis revealed two main determinants of high scores in female and male karate competitors. In women, these were thigh circumference and the speed of the mawashi-geri-kick roundhouse technique (i.e., the maximum number of delivered kicks in 30 s), whilst for men they were the extent of the sideway leg swing to the highest possible height (yoko-geri) and general endurance assessed with the bent arm hang test. Conclusion: Karate training should account for the determinants of high-level competitive karate performance identified in this study. Strengthening the lower limbs, exercises increasing hip joint mobility, low position movements, performing leg techniques in various planes and applying external loads undoubtedly increase a karate athlete’s strength and lead to the development of a more extensive repertoire of karate leg techniques, especially at the highest-scoring head level (jodan).
Given the ergogenic properties of β-alanyl-L-histidine (carnosine) in skeletal muscle, it can be hypothesized that elevated levels of circulating carnosine could equally be advantageous for high-intensity exercises. Serum carnosinase (CN1), the enzyme hydrolyzing the dipeptide, is highly active in the human circulation. Consequently, dietary intake of carnosine usually results in rapid degradation upon absorption, yet this is less pronounced in subjects with low CN1 activity. Therefore, acute carnosine supplementation before high-intensity exercise could be ergogenic in these subjects. In a cross-sectional study, we determined plasma CN1 activity and content in 235 subjects, including 154 untrained controls and 45 explosive and 36 middle- to long-distance elite athletes. In a subsequent double-blind, placebo-controlled, crossover study, 12 men performed a cycling capacity test at 110% maximal power output (CCT 110%) following acute carnosine (20 mg/kg body wt) or placebo supplementation. Blood samples were collected to measure CN1 content, carnosine, and acid-base balance. Both male and female explosive athletes had significantly lower CN1 activity (14% and 21% lower, respectively) and content (30% and 33% lower, respectively) than controls. Acute carnosine supplementation resulted only in three subjects in carnosinemia. The CCT 110% performance was not improved after carnosine supplementation, even when accounting for low/high CN1 content. No differences were found in acid-base balance, except for elevated resting bicarbonate following carnosine supplementation and in low CN1 subjects. In conclusion, explosive athletes have lower serum CN1 activity and content compared with untrained controls, possibly resulting from genetic selection. Acute carnosine supplementation does not improve high-intensity performance.
29 May 2009 in European Journal of Applied Physiology
Aging is a complex, multietiological process and a major risk factor for most non-genetic, chronic diseases including geriatric syndromes that negatively affect healthspan and longevity. In the scenario of "healthy or good aging", especially during the COVID-19 era, the proper implementation of exercise as "adjuvant" or "polypill" to improve disease-related symptoms and comorbidities in the general population is a top priority. However, there is still a gap concerning studies analyzing influence of exercise training to immune system in older people. Therefore, the aim of this review is to provide a brief summary of well-established findings in exercise immunology and immunogerontology, but with a focus on the main exercise-induced mechanisms associated with aging of the immune system (immunosenescence). The scientific data strongly supports the notion that regular exercise as a low-cost and non-pharmacological treatment approach, when adjusted on an individual basis in elderly, induce multiple rejuvenating mechanisms: (1) affects the telomere-length dynamics (a "telo-protective" effect), (2) promote short-and long-term anti-inflammatory effects (via e.g., triggering the anti-inflammatory phenotype), 3) stimulates the adaptive immune system (e.g., helps to offset diminished adaptive responses) and in parallel inhibits the accelerated immunosenescence process, (4) increases post-vaccination immune responses, and (5) possibly extends both healthspan and lifespan.
19 October 2020 in Frontiers in Aging Neuroscience
Late adulthood is associated with atrophy of brain areas, which contribute to cognitive deterioration and increase the risk of depression. On the other hand, aerobic exercise can improve learning and memory function, ameliorate mood, and prevent neurodegenerative changes. This study demonstrates the effect of Nordic walking (NW) and NW with poles with an integrated resistance shock absorber (NW with RSA) on aerobic capacity and body composition in postmenopausal women. It also measures the brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) serum levels and determines correlations with cognitive functions and depression symptoms. These relationships with the use of NW with RSA as a new form of exercise have not been described thus far. In this study, 31 women (NW – 16, NW with RSA – 15) participated in eight weeks of training. The findings showed that only NW with RSA training caused a significant decrease in body mass and body mass index (p < 0.05). There were no significant changes in GDNF levels between groups studied. Regarding BDNF, a significant decrease (p < 0.05) in the NW group and an increase (not statistically significant) in the NW with RSA group was found. A comparative analysis of cognitive and depression outcomes and changes in BDNF and GDNF concentration showed no significant differences in the efficacy of either form of training. Training loads resulted in a significant increase in VO2max in both the NW (p < 0.01) and NW with RSA (p < 0.05) groups. This indicates an improvement in cardiopulmonary efficiency of the examined women.
The aim of this study was to analyze selected indicators of oxidative stress. The study subjects consisted of 42 women with Hashimoto’s disease and a control group of 30 healthy women. The concentration of zinc (Zn) and copper (Cu) in the serum was determined by Atomic Absorption Spectrometry (AAS) and the total antioxidative potential by the Ferric Reducing Ability of Plasma (FRAP) method. In addition, an assessment of concentrations of thiobarbituric acid reactive substances (TBARS) and total phenolics was carried out. Our research showed a significant difference in TBARS concentration (p < 0.0001 (ES: 0.92)) without significant differences in Zn, Cu, FRAP and total phenolics concentrations. Analysis of the correlation of the obtained results of biochemical tests for both groups showed a highly significant dependence of FRAP and total phenolics concentration in the blood of the examined women (r = 0.5283, p = 0.0003). The obtained results indicate no differences in Cu, Zn, and FRAP concentrations in the blood between two analyzed groups and a significantly higher concentration of TBARS in Hashimoto’s thyroiditis women. The concentration of total phenolics significantly influences the value of the FRAP.