High-intensity Interval Training: Magical Training for Healthier Life

Tjelesno vježbanje važno je sredstvo za unapređenje zdravstvenog statusa ljudi. Budući da je kardiorespiratorni fitnes jedna od najvažnijih komponenata zdravstvenog fitnesa, potrebno je pronaći optimalne programe treninga za razvoj te komponente. Radi toga je u posljednje vrijeme iznimno popularan postao visokointenzivni intervalni trening (VIIT). Taj se program treninga sastoji od visokointenzivnih (85 – 95% VO2maks.) intervala rada koji se izmjenjuju s niskointenzivnim (40 – 60% VO2maks.) ili pasivnim intervalima odmora, a optimalni sadržaji za realizaciju treninga uključuju cikličke oblike kretanja. VIIT se može programirati u obliku kratkog i dugog formata, a oba omogućuju maksimiziranje vremena provedenog u zoni maksimalnog aerobnog napora. Uza statistički značajno unapređenje maksimalnog primitka kisika (VO2maks.) ovaj tip treninga utječe i na ostale čimbenike rizika od razvoja kardiovaskularnih bolesti, odnosno klinički značajno smanjuje potkožno masno tkivo, snižava sistolički i dijastolički krvni tlak i razinu glukoze u krvi te pozitivno regulira masnoće u krvi. Učinci treninga mogu se očekivati već nakon nekoliko tjedana vježbanja, a veličina promjena ovisit će o ukupnom volumenu treninga te inicijalnom statusu vježbača. VIIT je siguran program treninga, a brojna istraživanja upućuju na njegovu veću učinkovitost u odnosu prema umjerenointenzivnomu kontinuiranom treningu kod svih populacija. Zbog visokog intenziteta rada za provedbu VIIT-a potrebno je vrlo malo vremena, stoga on postaje vrlo učinkovita trenažna strategija za unapređenje zdravlja budući da je nedostatak vremena najčešće navedena barijera tjelesnom vježbanju. Naposljetku, za postizanje optimalnih rezultata programiranje i provedba programa treninga moraju biti povjereni stručnoj osobi, kineziologu, koji će znati prilagoditi program treninga pojedincu i uvjetima rada.Physical exercise is an important factor for the improvement of general health status. As cardiorespiratory fitness is one of the most important components of health-related physical fitness, it is essential to find optimal training programmes for its development. Recently, high-intensity interval training (HIIT) has become an extremely popular training programme used for that purpose. This training programme consists of high-intensity (85 – 95% VO2max) work intervals which are interspersed with low-intensity (40 – 60% VO2max) or passive recovery intervals with cyclic exercises as optimal training modes. HIIT can involve either short or long interval formats, both of which enable maximization of time spent in maximal aerobic zone. Besides producing significant improvements in maximal oxygen uptake (VO2max), this type of training affects other cardiovascular risk factors and clinically significantly decreases subcutaneous fat, systolic and diastolic blood pressure, and blood glucose levels while positively regulates blood lipids. Training effects can be expected within a few weeks of exercising, with the magnitude of changes depending on the total training volume and the subject’s initial health status. HIIT is a safe training programme that numerous studies have proven to be effectually superior to moderate-intensity continuous training in all populations. HIIT is performed with high intensity and thus requires short session time, which makes it a very time-efficient training strategy for health improvement as lack of time remains one of the most commonly cited barriers to regular physical exercise participation. Finally, for optimal results, training programme has to be created and implemented by an expert, a kinesiologist who will be able to adapt the training programme to the individual and the working conditions

ALTERATIONS IN REDOX HOMEOSTASIS FOLLOWING REPEATED SPRINT TRAINING

This study examined the effects of a 6-week repeated sprint training on redox-based homeostasis and their association with muscle damage. Fifteen male physical education students (aged 20.0±1.0 years; body weight 77.7±6.0 kg; height 181.0±4.4 cm; %body fat 8.7±3.0 %), familiar with intermittent activities, volunteered to participate in the study. Experimental training program consisted of 2-3 sets of 6-10 straight-line or shuttle 20-m repeated sprints with departures every 25 seconds and a 2-minute inter-set passive recovery. The training intervention lasted six weeks during which 18 training sessions were performed. The levels were measured of the following: 15-F2t-isoprostanes in plasma and 24-hour urine; superoxide dismutase, glutathione peroxidase and glutathione reductase in erythrocytes; uric acid and creatine kinase in serum after the first and the penultimate training session. The level of muscle damage following the repeated sprint exercise was not significantly altered (402 to 496 U/L; p=.151) and had no significant associations with the changes in markers depicting redox-homeostasis. A significant increase in plasma 15-F2t-isoprostanes (0.32 to 0.56 ng/mL; p=.026), and a subsequent decrease in glutathione reductase (7.7 to 3.4 U/g Hb; p<.001) were observed. Urinary 15-F2t-isoprostane levels were 25% greater at post-training, although this increase did not reach statistical significance. These results indicate that repeated sprint training stimulates the equilibrium in redox homeostasis developing antioxidant protection to the constantly increasing training load

Grizzly Bear and Human Use at Moth Sites in the Greater Yellowstone Ecosystem

In the greater Yellowstone ecosystem (GYE), alpine aggregations of army cutworm moths (Euxoa auxiliaris) are an important food source for grizzly bears (Ursus arctos horribilis). The number of grizzly bears utilizing this food source has increased since initial documentation in 1986 in the Shoshone National Forest, Wyoming. Dozens of bears congregate and feed on moths offering a unique viewing opportunity for bear-enthusiasts, professional media, and hikers. Currently, there is a limited understanding of how bears use these areas and no information on human use. The proximity of grizzly bears and humans poses a management concern for grizzly bears and human safety. Our objectives are to quantify grizzly bear and human use patterns and to identify areas of bear-human interactions. Our methods include occupancy and written surveys, GPS tracking unit deployment, and GIS analysis. Preliminary results from our first year of bear observations (n=220) showed 48% of bears foraging on moths, 20% foraging on vegetation, and 23% travelling. We recorded 5 groups and 26 groups of human use at two locations. We documented 18 bearhuman interactions, all on high-use travel routes common to bears and humans. Despite low human use all interactions between bears and humans resulted in bear avoidance of humans. At present, bear-human interactions appear to be very low but if human use increases, interactions will increase due to lack of alternate travel routes

Quaking Aspen Ecology on Forest Service Lands North of Yellowstone National Park

Quaking aspen (Populus tremuloides) occupy a small area in the northern Rocky Mountains, but are highly valued as wildlife habitat. Aspen stands in and around Yellowstone National Park commonly consist of few, large, mature overstory stems and numerous root suckers that do not grow above the browsing reach (≈ 2 m) of most wild ungulates. Our primary objective was to determine if the recruitment or density of aspen stems \u3e 2 m tall had changed from 1991 to 2006 on a portion of the Gallatin National Forest. The same aspen stands were surveyed in 1991 and 2006 in the 560 km² study area (n = 316). Secondary objectives were to determine if aspen density was influenced by elk (Cervus elaphus) browsing, conifer establishment, and cattle (Bos spp.) grazing. Mean recruitment stem density did not change from 1991 to 2006 (P = 0.95). Density of stems \u3e 2 m declined 12 percent from 1991 to 2006 (P = 0.04), which indicates that recruitment stems are not being produced at a sufficient rate to replace aging overstories. Areas with the greatest elk densities had the lowest recruitment stem densities and contributed the most to the decline. Although elk browsing seemed to play the largest role, conifer establishment and cattle grazing have also negatively impacted overstory recruitment in aspen stands. Even though elk numbers on the Northern Yellowstone Winter Range have declined since wolf reintroduction, aspen recruitment has not increased at the landscape level on the Gallatin National Forest

Impact of Body Composition on Performance in Fitness Tests among Personnel of the Croatian Navy

The purpose of this study was to determine the impact of body weight on fitness tests among the personnel of the Croatian navy. Forty two naval personnel (age 27±4.1 years; body mass 86.2±4.9 kg; height 184.6±7.4 cm; body fat percentage 17.3±5.2) participated in this study. In order to evaluate the fitness of the naval servicemen, we applied a testing procedure that included measurements of 7 fitness tests and 15 body anthropometric tests. A negative correlation was found between the body fat percentage and all the analyzed sprint tests and three anaerobic power tests (r), SP5 (r=–0.42), SP10 (r=–0.51), SP20 (r=–0.53), SJ (r=–0.45), CM (r=–0.57), SLJ (r=–0.67). Also a negative correlation was found between the body fat percentage and VO2max (r=–0.44). A positive correlation was found between the sprint test and the power performance test and thigh and calf girth. Spiriting ability is influenced by the strength of a person. This is one of the reasons why we found a positive correlation between the sprint test (SP5, SP10 and SP20) and thigh and calf girth. In this study we found a negative correlation between body fat percentages and all the sprint tests and three anaerobic power tests and VO2max. The ectomorph somatotypes have positive correlations with all variables. The mesomorph somatotypes have the greatest positive correlations with all variables. The endomorph somatotypes have negative correlations with all variables. According to the body composition of Croatian naval servicemen we can conclude that they need a sufficient level of strength and endurance for everyday tasks. The effectiveness of a weight-management program is determined by the success of the participants in losing the necessary amount of weight and being able to maintain that weight loss. This requires long-term tracking of these individuals in a naval environment