THE RELATION BETWEEN THE NUMBER OF REPETITIONS AND THE RELATIVE LOAD IN STRENGTH TRAINING

It was the aim of this study to determine the relationship between the number of repetitions that can be lifted at a range of percentages of the 1RM load in leg curl and bench press. Comparisons were made between males and females, and between long distance runners and sprinters. Findings suggest that this relationship is different between the two types of exercise. No differences were found between males and females. When working with highly trained athletes in bench press it is recommended that different regression equations are employed when studying sprint trained or endurance trained athletes

INFLUENCE OF DIFFERENT SNOWBOARD MATERIAL ON MUSCLE ACTIVITY AROUND THE ANKLE JOINT

This study investigates the influence of different snowboard materials, freestyle versus slalom, on muscle activity around the ankle joint, when using the up-unweighting technique. With a portable recorder EMG signals from the m. gastrocnemius (GAS) and m. tibialis anterior (TA) were recorded. As expected, highest activity levels were found for the m.GAS in frontside positions and for the m.TA in backside positions. In general, freestyle demands more muscle activity than slalom, probably because of the use of soft boots. Due to the traverse position of the feet on a snowboard, the muscle activation in the front and the rear leg was compared in freestyle and slalom. Only for the m.GAS, different activity patterns were found between the front and the rear leg which could indicate that both legs fulfil a different function in the up-unweighting technique

STRIDE CHARACTERISTICS RELATED TO RUNNING VELOCITY IN MAXIMAL SPRINT RUNNING

In sprinting, athletes and coaches strive to increase running speed by means of general and specific training methods. As running velocity is always the product of stride length and stride frequency, in the end, all methods aim to improve one or both of these factors. The relation between stride length, stride rate and running velocity has been discussed in the literature from different points of view. Alexander and Goldspink (1977) analysed the movement speed and stride characteristics of mammals. As they wanted to compare mammals of different sizes, they transferred stride characteristics and speed into dimensionless parameters, taking into account gravity and the length of the leg. Their conclusions should also be valid for humans. But it is not clear if these formulas can predict stride characteristics in maximal sprint running. It was the purpose of this study to analyse whether stride rate and stride length in maximal sprint running are related to running velocity as proposed by Alexander and Goldspink. A better understanding of this relationship could probably help coaches in developing sprint training strategies. In this study twenty male physical education students performed a maximal sprint over 100 meter and seventeen female students ran a 40 meter sprint. Running speed was continuously recorded by means of a velocimeter. Surface electrodes were used to record the muscle activity of four thigh muscles. These EMGrecordings were used to determine the duration of each stride cycle and to calculate mean stride rate per 5 meter-interval. The length of the lower limbs (h) and the acceleration of free fall (g) are used in the definitions of dimensionless running velocity (dV), stride rate(dSR) and stride length (dSL). The average maximal velocity of the male sprinters was 9.37 ±0.52 m/s while the female sprinters attained 7.38± 0.52 m/s. The relation between stride length and running velocity in male 100 meter performance was determined by means of linear regression analysis: dV=0.178+(1.175*dSL). This means that 87% of variance in running velocity seems to be related to differences in stride length. On the other hand variance in stride rate explains less than 20% of the variance in running speed. These findings are confirmed by the results in the 40 meter sprint of the female group: dV=(1.172*dSL)-0.0830 with 80% of variance in dV being explained by variance in dSL and 20% of dV explained by dSR. In contrast to the findings reported in the literature we found a clear linear relationship between dSL and dV, and no significant correlation between dSR and dV. These findings were confirmed in two separate analyses: one with females and another with males. The discrepancies between the results in the literature and this study can probably be explained by the fact that we analyzed pure sprint performances, in contrast to most studies analyzing differences in running speeds ranging from jogging to sprinting. In all-out sprinting, stride rate in the second 5 meter interval is already close to the maximum stride rate; from this point on differences in running speed are mainly due to changes in stride length

Dietary factors associated with obesity indicators and level of sports participation in Flemish adults : a cross-sectional study

BACKGROUND: Obesity develops when energy intake continuously exceeds energy expenditure, causing a fundamental chronic energy imbalance. Societal and behavioural changes over the last decades are held responsible for the considerable increase in sedentary lifestyles and inappropriate dietary patterns. The role of dietary fat and other dietary factors in the aetiology and maintenance of excess weight is controversial. The purposes of the present study were to investigate the dietary factors associated with body mass index (BMI) and waist circumference (WC), and to analyse whether dietary intake varies between subjects with different levels of sports participation. METHODS: Data for this cross-sectional study, including anthropometric measurements, 3-day diet diary and physical activity questionnaire, were collected by the Flemish Policy Research Centre Sport, Physical Activity and Health (SPAH) between October 2002 and April 2004. Results of 485 adult men and 362 women with plausible dietary records were analysed. Analyses of covariance were performed to determine the differences in dietary intake between normal weight, overweight and obese subjects, and between subjects with different levels of sports participation. RESULTS: Total energy intake, protein and fat intake (kcal/day) were significantly higher in obese subjects compared to their lean counterparts in both genders. Percentage of energy intake from fat was significantly higher in obese men compared to men with normal weight or WC. Energy percentages from carbohydrates and fibres were negatively related to BMI and WC in men, whereas in women a higher carbohydrate and fibre intake was positively associated with obesity. Alcohol intake was positively associated with WC in men. Subjects participating in health related sports reported higher intake of carbohydrates, but lower intake of fat compared to subjects not participating in sports. CONCLUSION: This study supports the evidence that carbohydrate, fat, protein and fibre intake are closely related to BMI and WC. The sex differences for dietary intake between obese men and women might reflect the generally higher health consciousness of women. Alcohol intake was only associated with WC, emphasizing the importance of WC as an additional indicator in epidemiological studies. Besides enhancing sports and physical activity, it is necessary to improve the knowledge about nutrition and to promote the well-balanced consumption of wholesome food

EFFECT OF CURVE AND SLOPE ON INDOOR TRACK SPRINTING

In contrast with the standard 400 m outdoor track, indoor sprinting is performed on the more compact 200 m track. The curves of these indoor tracks are normally constructed by means of lateral slopes to reduce the centripetal forces acting on the contact foot of the sprinter. The centripetal force (Fc) is determined by the body mass (m) and the squared running velocity (v) of the athlete, as well as by the radius (R) of the curve: Fc= (m * v²)/R. The inhanging body position of the athlete reduces partly these centripetal forces. It is clear that runners in the inner lanes have to work harder than those running in the outer lanes. Therefore it was the purpose of this study to analyze the time differences among 200 m sprint performances in lane 2, lane 4 and lane 6 on the Flanders Expo track, that will host the European Indoor Championships in the year 2000. This track consists of a unique construction as the inclination axis of the lateral slope is situated in the middle of lane 2. This implies uphill running in lane 3 to 6 when entering the curve and downhill running in lane 1. When leaving the curve it is just the other way round. The runner in lane 2 has to run a flat course over the total distance. Five national level male sprinters performed a 120 m all-out sprint from starting blocks in lanes 2, 4 and 6. A comparable group of six sprinters performed a 120 m sprint, running full speed through the second curve of the 200 m track in the same lanes. The order of running the different lanes was randomised. Infrared sensors and an electronic timing system of Intersoft Electronics enabled the recording of the mean running speed in 15 different intervals. EMG-recordings were used to determine the duration of each stride. A mean 200 m-time was reconstructed by combining the interval times of both groups of subjects. The results of this study indicate that at the end of a complete 200 m run, lane 6-runners have a mean advantage of 0.23 s and 0.10 s compared to lane 2 and lane 4 respectively. Surprisingly this difference is mainly due to the advantage of the forwarded starting position in lane 6, avoiding the uphill running part of the first curve and benefiting optimally of the downhill part at the end of the acceleration phase. The main problem in lane 4 is the uphill running in the first steps of the acceleration. Because of their flat course lane 2-runners, compared to the uphill running in lane 4 and 6, can maintain their maximal velocity one interval longer on entering the second curve. But in the middle of this curve the outer lanes, compared to lane 2, take significant advantage of the greater radius. In spite of the difference in the radius of the curve there is no significant difference in running speed among lane 4 and lane 6. It can be concluded that lane 6 takes advantage of lane 4 in the first curve and makes the difference with lane 2 in the first as well as in the second curve. Analysis of stride characteristics shows that almost all significant differences in running velocity can be explained by differences in stride length. It can be concluded that the chances of an athlete in 200 meter indoor sprinting depend on the lane he is running in

EFFECTS OF THE DIFFERENT POSITION OF THE FEET IN SLALOM AND FREESTYLE SNOWBOARDING ON MUSCLE ACTIVITY OF KNEE EXTENSORS

It was the purpose of this study to investigate the effect of the different position of the feet in slalom compared to freestyle snowboarding, on muscle activity of the m.rectus femoris and the m.vastus medialis when using the up-unweighting technique. Three male snowboard instructors participated in the investigation. They were experts in both snowboard styles. With a portable recorder EMG signals from the m.vastus medialis and m. rectus femoris were recorded. The knee extensors were more active in backside positions compared to frontside positions. The m. rectus femoris seems to fulfil a role in the stabilisation of the knee joint in backside positions. The m.vastus medialis seems to be important in the up-unweighting movement itself by performing a knee extension in backside position

Epstein-Barr virus genetics: talking about the BAC generation

Genetic mutant organisms pervade all areas of Biology. Early on, herpesviruses (HV) were found to be amenable to genetic analysis using homologous recombination techniques in eukaryotic cells. More recently, HV genomes cloned onto a bacterial artificial chromosome (BAC) have become available. HV BACs can be easily modified in E.coli and reintroduced in eukaryotic cells to produce infectious viruses. Mutants derived from HV BACs have been used both to understand the functions of all types of genetic elements present on the virus genome, but also to generate mutants with potentially medically relevant properties such as preventative vaccines. Here we retrace the development of the BAC technology applied to the Epstein-Barr virus (EBV) and review the strategies available for the construction of mutants. We expand on the appropriate controls required for proper use of the EBV BACs, and on the technical hurdles researchers face in working with these recombinants. We then discuss how further technological developments might successfully overcome these difficulties. Finally, we catalog the EBV BAC mutants that are currently available and illustrate their contributions to the field using a few representative examples

Assessment of the tropical Indo-Pacific climate in the SINTEX CGCM

A new coupled GCM (SINTEX) has been developed. The model is formed by the atmosphere model ECHAM-4 and the ocean model ORCA. The atmospheric and oceanic components are coupled through OASIS. The domain is global and no flux correction is applied. In this study, we describe the ability of the coupled model to simulate the main features of the observed climate and its dominant modes of variability in the tropical Indo-Pacific. Three long experiments have been performed with different horizontal resolution of the atmospheric component in order to assess a possible impact of the atmosphere model resolution onto the simulated climate. Overall, the mean state is captured reasonably well, though the simulated SST tends to be too warm in the tropical Eastern Pacific and there is a model tendency to produce a double ITCZ. The model gives also a realistic representation of the temperature structure at the equator in the Pacific and Indian Ocean. The slope and the structure of the equatorial thermocline are well reproduced. Compared to the observations, the simulated annual cycle appears to be underestimated in the eastern equatorial Pacific, whereas a too pronounced seasonal variation is found in the Central Pacific. The main basic features of the interannual variability in the tropical Indo-Pacific region are reasonably well reproduced by the model. In the Indian Ocean, the characteristics of the simulated interannual variability are very similar to the results found from the observations. In the Pacific, the modelled ENSO variability appears to be slightly weaker and the simulated period a bit shorter than in the observations. Our results suggest that, both the simulated mean state and interannual variability are generally improved when the horizontal resolution of the atmospheric mode component is increased

Annual Town Meeting Fayette, Maine Year Ending June 30, 2014

status: publishe

Climate change impact on waves in the Bay of Biscay, France

International audienceThe knowledge of offshore and coastal wave climate evolution towards the end of the twenty-first century is particularly important for human activities in a region such as the Bay of Biscay and the French Atlantic coast. Using dynamical downscaling, a high spatial resolution dataset of wave conditions in the Bay of Biscay is built for three future greenhouse gases emission scenarios. Projected wave heights, periods and directions are analysed at regional scale and more thoroughly at two buoys positions, offshore and along the coast. A general decrease of wave heights is identified (up to -20 cm during summer within the Bay of Biscay), as well as a clockwise shift of summer waves and winter swell coming from direction. The relation between those changes and wind changes is investigated and highlights a complex association of processes at several spatial scales. For instance, the intensification and the north-eastward shift of strong wind core in the North Atlantic Ocean explain the clockwise shift of winter swell directions. During summer, the decrease of the westerly winds in the Bay of Biscay explains the clockwise shift and the wave height decrease of wind sea and intermediate waves. Finally, the analysis reveals that the offshore changes in the wave height and the wave period as well as the clockwise shift in the wave direction continue toward the coast. This wave height decrease result is consistent with other regional projections and would impact the coastal dynamics by reducing the longshore sediment flux