bluuebunny/crossref_metadata_2025 huggingface dataset:
LSCT, a novel submaximal cycle test to monitor fatigue and predict cycling performance
Authors: Lamberts R P , Swart J , Noakes T D , Lambert M I
Published: November 2010

The purpose of this study was to determine the reliability and predictive value of performance parameters measured by a new novel submaximal cycle protocol (also known as the Lamberts and Lambert submaximal cycle test (LSCT)), on peak power and endurance cycling performance in well-trained cyclists. Seventeen well-trained competitive male road racing cyclists completed three peak power output tests (PPO) and three 40-km time trials (40-km TT) after familiarisation. Before each test all cyclists performed the LSCT as their warm-up method. Parameters associated with performance such as power, speed, cadence and rate of perceived exertion (RPE) were measured during the three stages of the test when cyclists rode at workloads coinciding with fixed predetermined heart rates (60%, 80% and 90% of HRmax). Heart rate recovery (HRR) was measured after the final stage of the test. Parameters measured during the second and third stage of the LSCT were highly reliable (intraclass correlation range: R=0.85-1.00) and associated with low typical error of measurements (TEM range: 1.3%-4.4%). Good relationships were found between the LSCT and cycling performance measured by the PPO and 40-km TT tests. Mean power had stronger relationships with measures of cycling performance during the second (r=0.80-0.89) and third stage (r=0.91-0.94) of the LSCT than HRR (r=0.55-0.68). The LSCT is a reliable novel test which is able to predict peak and endurance cycling performance from submaximal power, RPE and HRR in well-trained cyclists. As these parameters are able to detect meaningful changes more accurately than VO2max, the LSCT has the potential to monitor cycling performance with more precision than other current existing submaximal cycle protocols.
Comparison of energy expenditure and fat oxidation from a graded exercise test with a moderate-intensity interval training session in obese men
Authors: Alkahtani S A , Hills A P , King N A , Byrne N M
Published: November 2010

Increasing fat oxidation is a common goal of exercise training for managing obesity. While constant load exercise at the intensity associated with the level of maximal fat oxidation (MFO) has been shown to be effective, there is a growing interest in the use of moderate-intensity interval exercise. This study compares fat oxidation rate from a FATmaxtest with a moderate-intensity interval training session in obese men. Twelve sedentary obese males (age 27.2±4.1 years; BMI 30.5±3.2 kg/m2; %fat mass 32.5±4.5) completed two exercise sessions: a graded exercise test (GXT) to determine MFO and maximal aerobic power (VO2max), and an interval cycling session during which respiratory gases were measured. The 30-min interval session involved 5-min repetitions of workloads 20% below and 20% above the FATmaxintensity (FAT-INT). Mean VO2maxwas 31.8±5.6 ml/kg/min and all participants achieved ≥3 of the designated VO2maxtest criteria. The average MFO was low (0.14±0.08 g/min) and occurred at 34±6%VO2max. The MFO identified during the GXT was not significantly different compared with the average fat oxidation rate in the FAT-INT session (0.16±0.09 g/min). During the FAT-INT session, fat oxidation rate increased with time; the highest rate (0.18±0.11 g/min) in minute 25 was significantly higher than the rate at minute 5 and 15 (p=0.004 and 0.04 respectively). In the FAT-INT, energy expenditure (EE) at 15 min (5.06±0.9 kcal/min) and at 25 min (5.13±0.9 kcal/min) were significantly greater than the EE at the MFO intensity (4.5±1 kcal/min) (p=0.003 and 0.001 respectively). Fat oxidation contributed 27±13% of the EE at the MFO workload during the GXT, 27±14% during the first half of interval training session, and was 32±14% during the second half of the FAT-INT session. There was no significant difference between blood lactate concentration measured at the MFO intensity and the end of FAT-INT session. This study shows in a cohort with low aerobic power, fat oxidation during the FAT-INT session was comparable in the first 15 min and greater in the second 15 min, than the MFO determined during a GXT. Future research may consider if the varying workload in moderate-intensity interval training helps adherence to exercise without compromising fat oxidation.
Effect of weight training on sprinting performance, flexibility and strength
Authors: Azeem K , Al Ameer A
Published: November 2010

Weight training has motivated and attracted the youth to develop their strength and build their muscles. Apart from developing a wholesome personality it also helps in to keep a person fit and healthy. The purpose of the study was to find out the effect of weight training (WT) on sprinting performance, flexibility and strength of the 20 students. A 45 min WT schedule twice a week for 12 weeks was administered. The test considered were strength (1 RM for all the WT components), 50 m run and sit and reach. Speed is one of the variables which is associated with the fitness of the subjects. The analysis of the data reveals a significant (p<0.05) improvement sprinting performance with the mean±SD reading in the pre-test 0.43±0.07 s and in the post-test of 0.41±0.06 s. Flexibility improved (p<0.05) from pre to post test (26.7±9.3) and (31.8±8.4). Squat exercise increased (p<0.05) from pre to post test (75.5±15.1 kg) and (99.5±14.7 kg). The bench press exercise increased (p<0.05) from pre to post test (48.8±24.1) and (65.5±24.3 kg). Barbell front press exercise increased (p<0.05) from pre to post test (24.5±12.7 kg) and (34.4±12.4 kg). High pull downs improved the strength of the lats and back muscles, and the analysis points towards it with from pre to post test (39.5±11.1 kg) and (59.0±10.3 kg; p<0.05). Barbell curls exercise increased (p<0.05) the strength of the biceps muscles from pre to post test (17.3±7.3 kg) and (27.0±7.9 kg). The study has revealed that WT improved strength and also showed some improvement in speed and flexibility.
Effects of training and competition on the salivary cortisol concentrations of weightlifters
Authors: Crewther B T , Heke T , Keogh J W L
Published: November 2010

Cortisol (C) plays an important training role by regulating the availability of metabolic resources and by also controlling long-term changes in protein metabolism. The secretion of C is sensitive to the stressors of exercise, training and competition, which may subsequently influence athlete performance and adaptation. Little research has examined the effects of training and competition on the C concentrations of weightlifters. The aim was to examine the effects of training and competition on the salivary C (Sal-C) concentrations of weightlifters. Five male and four female Olympic weightlifters were monitored across a 5-week period before a major competition. Participants provided saliva samples across 10 workouts to assess the weekly effects of heavy (≥200 sets) and light (≤100 sets) training volume on Sal-C concentrations. During this period, the Sal-C concentrations and one repetition maximum (1RM) lifts for the snatch, clean and jerk, and the Olympic total, were also compared across two simulated and two actual competitions. The competition data were pooled for analysis. The actual competitions produced higher (128%-130%) Sal-C concentrations (p<0.001) and superior (1.9%-2.6%) 1RM lifts for the clean and jerk, and the Olympic total, compared with the simulated competitions (p<0.05). Individual Sal-C concentrations before the simulated competitions were positively correlated to all the 1RM lifts (r=0.48-0.49, p<0.05). There were no significant changes in Sal-C concentrations with training. Our data suggest that higher C concentrations may benefit the 1RM lifts of Olympic weightlifters during actual (v. simulated) competitions. On an individual level, a positive trend was also noted between C concentrations and the 1RM lifts during the simulated competitions.
Influence of a 10-day stay at high altitude on athletes
Authors: Suchy J
Published: November 2010

A number of studies have been recently published describing the positive effect of a traditional 3-week stay at high altitude on athletes' performance and biochemical parameters. During our studies with top trainers the authors found that many of them now use 10- to 12-day stays and training at altitude. For those reasons the authors focused our research on assessing the influence of 10 days at altitude on selected biochemical and physiological parameters. Participants were 10 athletes (age=19 years) regularly competing in the Cross-Country Skiing Cup. According to the fact the experiment took place during a training period, subjects went mostly through an aerobic training load. The main part of the data collection took place in the training camp in Livigno (IT, 1850 m above the sea). Subjects were tested for selected figures in the blood count three times - before their departure, right after their return and 10 days after the return. The tested figures were: haemoglobin (g/l), red blood cell distribution width (%), haematocrit. The data collection of morning pulse rate began 22 days before and ended 27 days after the return. The authors confirmed a significant (p<0.03) positive effect for a 10-day stay at altitude on biochemical and physiological parameters. Data clearly show an average elevation of all selected figures in the blood count after the return from the altitude compared with data before. Mean (SD) morning pulse rate for 22 lowland days was 55 (3) beats/min: this increased to 62 (6) at altitude and returned to 50 (3) after the return. The changes in selected biochemical and physiological parameters of monitored sportsmen confirm the positive effects of a 10-day stay and training in areas 1850 m above sea. The study was supported by MSM0021620864.
Cardiovascular disease risk factors in Welsh adolescents: where are we now?
Authors: Thomas N E , Williams R , Rowe D A , Baker J S
Published: November 2010

The aim was to investigate secular trends in cardiovascular disease (CVD) risk factors in Welsh adolescents between 2002 and 2007. CVD risk factor data were examined from two school-based cross-sectional studies. The initial study (September to October, 2002) included 73 participants, aged 12.9±0.3 years. The final study of 90 participants, aged 12.9±0.4 years, was completed during September to October, 2007. Measurements included adiposity, physical activity (PA), physical fitness (PF), diet, total cholesterol, high-density-lipoprotein cholesterol, low-density-lipoprotein cholesterol, triglyceride, fibrinogen (Fg) and high-sensitivity C reactive protein (hs-CRP). On both occasions, testing was carried out in the same school, and by the same experienced researcher using identical procedure. PA and PF levels improved for boys and girls in 2007; however, 80% of girls still did not meet the recommended 1 h/day of moderate PA. For both sexes, dietary fat intake did not differ between 2002 and 2007 cohorts; Welsh adolescents continued to consume a diet that was too high in saturated fat. Although mean adiposity tended to decrease between 2002 and 2007 in boys, this was not significant (p≥0.05). Overall, there were improvements in mean lipid profile and inflammatory status (p<0.05). More adolescents in the earlier cohort exceeded the recommended levels for lipids, Fg and hs-CRP. Despite our finding that overweight continues to be widespread in Welsh adolescents, levels had not risen in our later cohort. This concurs with recent international evidence which suggests a “levelling off” in childhood obesity. The authors identified an upward trend in PA and PF, but no changes in dietary habits. This suggests that increased PA/PF, without dietary modification, has little effect on adiposity. Generally, our findings present a positive trend in lipid profile, as well as inflammatory factors. These improvements may be linked to the enhanced PA and PF profiles of the 2007 cohort.
Use of nutritional supplements by elite adult Portuguese athletes is not associated with nutritional intake
Authors: Sousa M , Fernandes M J , Moreira P , Teixeira V H
Published: November 2010

This study aimed to characterise the nutritional intake according the use of nutritional supplements (NS) by elite adult Portuguese athletes. Two hundred and two adult (23±4 years) athletes (78% males), representatives of Portugal in 13 sports, voluntarily filled a semiquantitative food-frequency questionnaire and a questionnaire about the use of NS. The total nutritional daily intake did not consider the nutrients provided by NS. Statistical analyses were performed using SPSS V.16.0. The majority of athletes (74%) reported having used at least one NS in the previous year, with a mean consumption of 5.9±3.7 NS per athlete. The most frequently consumed nutritional supplements were sport drinks (63%), proteins (58%), magnesium (56%), iron (30%), vitamin C (29%), sport gels (23%), antioxidants (21%), vitamin B12 (15%) and vitamin E (9%). The mean energy intake was 2875±1313 kcal/days, for males, and 2612±1152 kcal/days, for females. For proteins, the males' intake was 1.7±0.8 g/kg/days and females' intake was 2.1±1.2 g/kg/days. Males consumed 4.8±2.5 g/kg/days of carbohydrates, while females consumed 5.6±2.6 g/kg/days. Intake of less than recommended was observed in 33% for vitamin E in females, and 17% for vitamin E, 5% for folate and 5% for magnesium, in male athletes. For all other micronutrients intakes were above recommended amounts for both genders. There were no differences in the vitamin and mineral intake between supplement users and nonusers, for both genders. The use of NS is very prevalent in elite adult Portuguese athletes and not associated with nutritional total intake.
Effect of milk protein addition to a rehydration solution consumed after exercise in the heat
Authors: James L J , Clayton D , Evans G H
Published: November 2010

Milk has been shown to be an effective post-exercise rehydration solution, but the specific effects of milk protein on rehydration after exercise are unknown. This study examined the effects of milk protein on rehydration after exercise in the heat, via the comparison of carbohydrate and carbohydrate-milk protein solutions matched in terms of energy density and electrolyte content. Eight male subjects (mean±SD: age 21±3 years, height 1.78±0.08 m, body mass 75.7±11.6 kg) lost 1.9±0.2% of their initial body mass via intermittent exercise in a warm environment (35±0.1°C, 50.9±2.1% RH). Subjects then rehydrated with 150% of their body mass loss over 1 h, with either a 65 g/l carbohydrate solution (C) or a 40 g/l carbohydrate, 25 g/l milk-protein solution (CP). Urine samples were collected before and after exercise and for 4 h after rehydration. After rehydration, total cumulative urine output was greater for trial C (1212±310 ml) than trial CP (931±254 ml) (p<0.05), while total drink retention was greater after ingestion of drink CP (55±12%) than drink C (43±15%; p<0.05). At the end of the study period, whole body net fluid balance (estimated from fluid lost through sweat and urine production and gained through drink ingestion) was less negative for trial CP (−0.26±0.27 l) than trial C (−0.52±0.30 l), and although net negative for both trials, was significantly negative only after ingestion of drink C (p<0.05). These results suggest that after exercise in a warm environment, a carbohydrate-milk protein solution is better retained than a carbohydrate solution, when solutions are matched for energy density and electrolyte content. Some of the beneficial post-exercise rehydration effects of milk might be attributable to the milk protein.
Comprehensive model to enhance road cycling performance
Authors: Cangley P , Passfield L , Carter H , Bailey M
Published: November 2010

Modelling has been utilised in competitive road cycling to identify performance optimisations that would conventionally require extensive experimental testing. However, the validity of current models is limited by incomplete representation of the cycling environment and insufficient frequency of simulation. A three dimensional road cycling model has been developed that extends existing models by combining bicycle mechanics, rider biomechanics and environmental conditions into a single dynamic system. A system of rigid bodies linked by joints and driven by actuators has been built using the MATLAB toolboxes Simulink and SimMechanics. Each body is defined in respect of mass, inertia tensor, dimension and centre of gravity. The system operates in forward dynamics mode such that a simulation inputs forces to the equations of motion which are numerically integrated at <0.1 s time steps and output system motion. Bicycle freedoms include longitudinal/lateral translation together with roll, pitch and yaw rotation. Submodels reproduce transmission, tires, wheels, frame and steering geometry. A 16 segment rider applies experimentally obtained pedal forces coordinated with upper body roll and steering input. Environmental parameters include course track and gradient obtained from digital maps together with experimentally measured wind speed/direction. The model has been validated in a trial with 20 experienced time trialists riding a 2.5 mile undulating section of the Cycling Time Trials course G10/42 at competitive pace. The course track/profile and the cyclist characteristics were loaded into the model and a simulation predicted individual completion times. Mean actual time was within 1.4 (±0.7)% of the mean predicted time. The model was then used to optimise application of a variable power pacing strategy over the same course1. A 2.9 (±0.9)% time saving was obtained which would typically represent a 40 s advantage over a full 10 mile time trial. Further model applications include investigating the mechanical performance advantages of factors that are both difficult and time consuming to examine experimentally such as saddle position, bicycle/rider weight and tire characteristics.
Anthropometric and physiological factors predicting young adults' motor skills
Authors: Iconaru E I , Ciucurel C , Ciucurel M M , Georgescu L , Toma S , Tudor M I
Published: November 2010

Recent studies indicate that performance of motor skills is influenced by a diversity of physiological parameters, such as weight status, aerobic capacity, endurance and muscular strength, but the scientific determinants of physical performance are very specific. The aim was to identify the anthropometric and physiological determinants of motor skills in young adults. The authors studied anthropometric and physiological factors (as predictor variables) among 230 subjects (average age 22 years, sex ratio 1/1). The authors considered as criterion variable the results of the Fundamental Movement Skills Test, a Romanian semiquantitative test utilised for evaluation of candidates for entrance into Romanian Physical Education and Sport Faculties. Above the measured variables, the strongest predictors for the motor skills (for a statistical significance level p=0.002) were: the body mass index, the aerobic capacity (Astrand-Rhyming test), the anaerobic power (Sargent test), the statokinesigram and the vital capacity. These unified factors, as a battery test, account for 65% of the variance of the subjects' motor skill level (multiple R square=0.65, multiple R=0.805). The acquisition of motor skills is substantially associated with some anthropometric and physiological determinants. Thus, the understanding of these important factors is beneficial for large groups of individuals, by helping professionals in physical education and sport to develop a conceptual model of human performance. Our findings suggest that the most relevant five factors predicting the motor skills in young adults are the body mass index, the aerobic capacity, the anaerobic power, the statokinesigram and the vital capacity. Furthermore, more effective studies appear like innovative approaches, in condition of applying the multiple regression and mitigating the effect of multicollinearity.
Differences in kinematics and heart rate variability between winner and loser of various skilled levels during competitive golf putting tournament
Authors: Choi J S , Kim H S , Mun K R , Kang D W , Kang M S , Bang Y H , Oh H S , Yi J H , Lim Y T , Tack G R
Published: November 2010

Putting is a crucial stroke to determine winning in golf. Putting is more delicate than any other strokes in golf. To keep better putting stroke, psychological factors as well as physical factors are important for golfers. The purpose of this study was to compare differences in kinematic and psychological variables between winner and loser of three skilled levels during competitive golf putting tournament. The participants consisted of 3 groups based on their skill levels: PG (8 professional golfers), RG (8 recreational golfers) and NG (8 novice golfers). Each group performed 8 tournaments by attempting 2.1 m putting from the hole. 3D motion analysis system with 6 high speed cameras and BIOPAC ECG module were used to acquire kinematic data and ECG. To compare differences between winner and loser for each group, time phase of putting stroke, smoothness by jerk cost function (JC), heart rate (HR), ratio of low and high frequency component (LF/HF) in heart rate variability and CSAI-2 scores (competitive state anxiety inventory 2) were used. There was a significant difference in back-swing phase time ratio between PG and other groups and in JC at the putter toe between NG and other groups. There was a significant difference in LF/HF and self-confidence score of CSAI-2 between winner and loser within PG. While PG and RG showed similar kinematic performance, they showed different LF/HF. The tonic states derived from cardiac activity indicated that a higher skilled level was associated with increased LF. Increased LF is associated with increased automaticity and decreased attention demands, which means that increased mental workload reduces LF. For PG, it may reveal that psychological factor is one of the important factors for the better performance during competition. Further studies are necessary to clarify psychological factors of putting by using different measurement techniques such as galvanic skin response.
Ball height during backswing and its influence on tenpin bowling performance
Authors: Razman R , Cheong P G
Published: November 2010

In tenpin bowling, it is common for coaches to suggest that bowlers display a higher backswing in order to generate higher peak ball velocity during swing (PBvel). This stems from the assumption that the swing is akin to a pendulum, whereby the speed of the ball is dependent on the potential energy gained from its starting height. The primary objective of this study was to ascertain whether maximum ball height (BHNorm) during backswing is related to PBvelor bowling score average (BSave). The study also compared BHNormbetween elite and backup bowlers. Participants were assigned into two groups based on their BSave over three tournaments, with those averaging above 200 pin falls placed in the elite group. There were 18 elite (M=10, F=8; BSave 213±7) and 12 backup bowlers (M=7, F=5; BSave 181±9). Ball height and velocity data were derived from Kwon3D system utilising four 100 Hz cameras. BHNormwas the vertical distance between the maximum ball height during backswing and the lowest point during swing, normalised to subject's height. PBvelwas the maximum linear forward velocity of the ball near release. Participants aimed for a strike at each of the four trials, the mean scores were used. In terms of relationship to bowling performance, BHNormhad no significant (p<0.05) relationship to BSave (r=0.00) and PBvel(r=0.01). Comparisons of BHNormbetween the elite and backup group also yielded no significant differences. Contrary to the popular notion that raising the ball higher will lead to higher release velocity, the height a ball is raised during backswing does not seem to correspond with higher ball speeds, nor does it relate to better bowling scores. The latter is supported by the fact that there was no significant difference in BHNormbetween the different level bowlers. It can be suggested that the ball height during backswing is more of a choice of individual preference rather than the need to generate more ball speed.
Validity of two kinematic systems for calculating force and power during squat jumps
Authors: Crewther B T , Kilduff L P , Cunningham D , Cook C , Yang G-Z
Published: November 2010

Force and power are key exercise outputs in research and training practice. The direct acquisition of this kinetic data typically requires a force plate, which is not always practical and cost-effective, and generally limited to laboratory-based settings. Thus, kinematic systems (eg, linear position transducers, accelerometers) are becoming increasingly popular as tools for calculating force and power in situ during exercise. The aim was to assess the validity of a commercial linear position transducer and accelerometer for calculating force and power during squat jumps. Seven healthy males performed 2×single repetition squat jumps with four loads (20 kg, 40 kg, 60 kg and 80 kg). The squats were performed on top of a Kistler force plate. A commercial linear position transducer (Gymaware (GYM)) and accelerometer (Myotest (MYO)) were attached to the bar to assess concentric peak force (PF) and peak power (PP), based on the combined mass of the external load and each subject. Data were pooled across all loads for analysis. The PF and PP data from the GYM and MYO systems were strongly correlated with the force plate data (r=0.84-0.93, p<0.001) and also with each other (r=0.90-0.97, p<0.001). The mean PF and/or PP values calculated from the GYM and MYO systems were found to be 4.5%-6.5% higher than the measured values from the force plate (p<0.01). The PF and PP data from the linear position transducer and accelerometer showed strong relative validity compared to the force plate, but some differences in absolute validity were noted. The two kinematic systems provide other benefits (eg, portability, ease of use, cost effectiveness) for assessing PF and PP during squat jumps or similar isoinertial exercises.
Analysis of the perceived healthy lifestyles of adults and older adults of the Empowering Health Learning for the Elderly project: effects of gender
Authors: Tortosa-Martínez J , Soler-Gomis A , Vega-Ramirez L , Plaza-Salán A
Published: November 2010

The Empowering Health Learning for the Elderly project analysed the perceived health and lifestyle factors of a sample of 1200 adults of four different European countries (Italy, Spain, France and the Netherlands). Didactic tools were developed for promoting healthy lifestyles related to sleep, alcohol and smoking, nutrition, pharmacology, physical exercise, memory and emotional intelligence. The instrument used was a questionnaire with 64 multiple choice questions. The data discussed here represent only the Spanish sample (300). The perceived health of the sample is highly positive, with more men perceiving their health as good (71%) than women (66%). The number of sleeping hours is considered sufficient for most of the sample but the quality of these hours is considered satisfactory for only 50% of the sample. Men report higher positive percentages regarding quality of sleep than women. Women report to have better eating habits than men. About 48% of the study recalls having memory problems in some degree. Women complain more about learning new abilities and spatial orientation problems, while men complain more often about remembering names or finding objects that they need. Around 45% of men consider their physical fitness as good compared to nearly 50% of women. 40% of women refer to practice physical exercise between 3 and 5 days compared to 36% of men. The perceived health of the sample is quite high. However, the majority of the sample is highly educated, with a high socioeconomic status and a strong background on health education. Intellectual functioning is the most solid psychological factor for predicting health. Men have a better perception of their health and report better quality of sleep, but have worse eating habits and do less physical activity than women.
Reliability of an isokinetic endurance task
Authors: Hayes P R , Cockburn E , Thomas K
Published: November 2010

The purpose of this study was to determine the reliability of an isokinetic endurance task. After habituation, 10 physically active males completed three trials of an isokinetic endurance task on nonconsecutive days. The task was performed on a Cybex Norm dynamometer. It consisted of 30 maximal, concentric and eccentric, contractions of the hip extensors at 180°/s. Reliability was assessed through technical error of measurement (TEM), relative TEM, group coefficient of variation and intraclass correlation (ICC). During eccentric actions both average power per repetition (APR) and work done (WD) showed very good reliability. For APR the group coefficient of variation was 8.0% and the ICC was 0.93. The TEM and relative were 28.9 W and 16.3%, respectively. For WD these values were 5.6%, 0.94%, 451% and 12.4% J, respectively. By contrast, fatigue index (FI) demonstrated poor reliability with TEM, group coefficient of variation and ICC values of 16.2%, 26.1% and 0.32%, respectively. The reliability from the concentric actions demonstrated more variable results. The group coefficient of variation was low for both APR (5.9%) and WD (5.3%), however, the ICC values were lower than for eccentric actions with a score of 0.85 for both APR and WD. Once again FI demonstrated low reliability with a TEM, group coefficient of variation of 12.8%, 28.3% and ICC of 0.72%. The reliability of the hip extensors, both concentrically and eccentrically, depended on the dependent variable measured. FI showed poor reliability, while WD showed high reliability.
Role of neural tension in stretch-induced strength loss
Authors: Tallent J , Greene B , Johnson C D , McHugh M P
Published: November 2010

The aim of the study was to examine whether increased neural tension during passive hamstring stretching contributes to stretch-induced strength loss. Eleven healthy subjects performed maximal isometric knee flexion contractions (100°, 80°, 60° and 20°) before and after a series of hamstring stretches (six 1-min stretches), performed in either a spinal neutral position or a neural tension position. Effect of stretch technique (neutral or neural tension) on passive resistance to stretch, strength-induced strength loss and electromyography activity during strength tests was assessed with repeated measures analysis of variance. Passive resistance to stretch was reduced by 19% after the series of stretches (p=0.001) with no difference between neutral or neural tension stretches (p=0.41). Stretch-induced strength loss was greater (p=0.043) after the neural tension stretches (13%) vs the neutral stretches (5%). There was an apparent rightward shift in the length tension curve after neutral stretches with a 15% strength loss at muscle lengths shorter than optimum, and a 10% gain in strength at muscle lengths longer than optimum (p<0.001). This effect was not apparent after neural tension stretches where strength loss was 21% at muscle lengths shorter than optimum and 9% at muscle lengths longer than optimum. The addition of neural tension to hamstring stretching increased stretch-induced strength loss but this was not associated with observable neural inhibition. The absence of a rightward shift in the length-tension curve after neural tension stretching indicates that muscle fibre shortening during isometric contractions was unaffected, presumably because tendon-aponeurosis compliance was not increased.
Changes in muscle tendon unit stiffness with increasing running speed
Authors: Salvidge C , Hayes P R
Published: November 2010

The spring mass model of running proposes that with increases in running speed there will be decreases in ground contact time and concomitant increases in muscle tendon unit (MTU) stiffness. Previous studies examining these relationships have used either a limited number of running speeds or low numbers of participants. To date equivocal results have been found between changes in MTU stiffness and running speed. The purpose of this study was to examine changes in MTU stiffness with changes in running speed. After institutional ethical approval 18 physically active males (aged 20.8±0.9 years; stature 1.77±0.18 m; body mass 75.4±11.1 kg) completed the maximal anaerobic running test (MART). The MART test began at 11.9 km/h with each stage increasing by 1.37 km/h until participants could no longer complete a 20 s stage. Throughout the test ground contact time (Tc) was recorded at 1000 Hz using the Optojump Next system. Ground Tcs were used to calculate MTU stiffness using the method of Morinet al1. Regression analysis revealed near perfect relationships with running speed for both Tc (F 1, 8=295.101; p<0.001; R2=0.970; SEE=0.007 ms) and MTU stiffness (F 1, 8=725.844; p<0.001; R2=0.988; SEE=0.798 kN/m). This study has used more participants and a wider range of participants than previous literature. These results provide strong supporting evidence for the spring mass model of running.
Effect of pre-exercise stretching on repeat sprint performance
Authors: Musham C , Hayes P R
Published: November 2010

The purpose of this study was to investigate the effect of pre-exercise stretching on repeated sprint performance over 20 m. Eight participants completed three conditions, active static stretching (AS), dynamic stretching (DS) and control (CON), in a counterbalanced order. Each pre-exercise condition was preceded by a 3-min walk. After stretching, participants completed the first 15 min of the Loughborough intermittent shuttle test (LIST). All statistical comparisons are made using qualitative magnitude based inferences comparing the stretching condition with CON. The results show that AS has probably had no beneficial or disadvantageous effect on performance on the first 20-m sprint (positive 57%, trivial 27%, negative 16%). There appear to be no beneficial or negative effects with the use of AS on 20-m sprint performance halfway through the LIST (positive 31%, trivial 32%, negative 37%). After 15 min of the LIST, AS appeared to exert a negative effect on sprint performance with 20-m sprint slowing (positive 35%, trivial 0%, negative 65%). DS improved performance on the first sprint (positive 89%, trivial 9%, negative 16%). By the midpoint, the beneficial effects of DS on sprint performance appear equivocal (positive 53%, trivial 28%, negative 18%). In the last sprint DS appeared to have a positive effect on performance (positive 80%, trivial 0%, negative 20%). Sprint performance during a 15-min segment of the LIST appears to be enhanced with DS. By contrast, 20-m sprint performance declined over the 15 min after AS.
Generalised ligament laxity and shoulder dislocations after sports injuries
Authors: Akhtar M A , Robinson C M
Published: November 2010

This study was performed to assess the incidence of generalised ligament laxity in patients presented with shoulder dislocations. Prospective data were collected for patients presented with shoulder dislocations between August 2008 and August 2009 under the care of a specialist shoulder surgeon including demographic details, types of dislocation, mechanism of injury and generalised ligament laxity. Clinical examination was used to assess the ligament laxity using the Beighton score. Laxity is scored on a 0-9 scale. Scores of 4 or above are indicative of generalised ligament laxity. Brighton criteria is used to diagnose benign joint hypermobility syndrome (BJHS) and use signs and symptoms along with Beighton score. There were 82 patients with a mean age of 30 years. There were 77 male (94%) and 5 (6%) female patients. 34 patients (41%) attended after first time shoulder dislocation, 37 (45%) after recurrent shoulder dislocations and 11 (13%) for revision shoulder stabilisation. The most common cause of shoulder dislocation was sports related injuries in 48 patients (68%). The most common sports involved was rugby in 22 (46%) patients followed by football in 15 (31%) patients. 75 (91%) patients had anterior shoulder dislocations and 6 (7%) had multidirectional instability. The average Beighton score for these patients was 3.1 with a range from 0 to 9. 35 patients (43%) in this group had a Beighton score of 4 or more indicating generalised ligament laxity. 15 patients (18%) fulfilled the Brighton criteria for BJHS. 12 patients (15%) had a first degree relative with generalised ligament laxity. The authors found that there is a high incidence (43%) of generalised ligament laxity in patients with shoulder dislocations after sports injuries. Appropriate advice should be given about the risk of shoulder dislocations in patients with generalised ligament laxity.
LIGHT MESON DECAY IN THE ${\rm C}\,{}^{3}\!P_{0}$ MODEL
Authors: DE QUADROS J. N. , DA SILVA D. T. , DA SILVA M. L. L. , HADJIMICHEF D.
Published: November 2010

Having its origin in a successful mapping technique, the Fock–Tani formalism, the corrected [Formula: see text] model [Formula: see text] retains the basic aspects of the [Formula: see text] predictions with the inclusion of bound-state corrections. Evaluation of the decay amplitudes has been performed for open-flavor strong decays in the light meson sector. The bound-state corrections introduce a fine-tuning for the former [Formula: see text] model, in particular, the adjustment of the D/S ratios in b1→ωπ, a1→ρπ and h1→ρπ decays.
ONE-LOOP QUANTUM COSMOLOGICAL CORRECTION TO THE GRAVITATIONAL CONSTANT USING THE KINK SOLUTION IN DE SITTER UNIVERSE
Authors: DARABI F. , JALALZADEH S.
Published: November 2010

In this paper, we show the equivalence between a classical static scalar field theory and the (closed) de Sitter cosmological model whose potential represents shape invariance property. Based on this equivalence, we calculate the one-loop quantum cosmological correction to the ground state energy of the kink-like solution in the (closed) de Sitter cosmological model in which the fluctuation potential V′′ has a shape invariance property. It is shown that this type of correction, which yields a renormalized mass in the case of scalar field theory, may be interpreted as a renormalized gravitational constant in the case of (closed) de Sitter cosmological model.
SU(3)L ⋊ (ℤ3 × ℤ3) GAUGE SYMMETRY AND TRI-BIMAXIMAL MIXING
Authors: HATTORI CHUICHIRO , MATSUNAGA MAMORU , MATSUOKA TAKEO , NAKANISHI KENICHI
Published: November 2010

We study an effective gauge theory whose gauge group is a semidirect product G = G c ⋊ Γ with G c and Γ being a connected Lie group and a finite group, respectively. The semidirect product is defined through a projective homomorphism (i.e. homomorphism up to the center of G c ) from Γ into G c . To be specific, we take SU (3) L as G c and ℤ3 × ℤ3 as Γ. We notice that the irreducible representations of the gauge group G necessarily contain three G c -multiplets in spite of the Abelian nature of Γ = ℤ3 × ℤ3. This triplication phenomenon is due to the semidirect product structure of G. We suggest that the appearance of three families is attributable to this triplication. We give a toy model on the lepton mixing and show that under a particular vacuum alignment the tri-bimaximal mixing matrix is reproduced.
NEWTON'S EQUATION ON THE κ-SPACETIME AND THE KEPLER PROBLEM
Authors: HARIKUMAR E. , KAPOOR A. K.
Published: November 2010

We study the modification of Newton's second law, upto first order in the deformation parameter a, in the κ-spacetime. We derive the deformed Hamiltonian, expressed in terms of the commutative phase space variables, describing the particle moving in a central potential in the κ-spacetime. Using this, we find the modified equations of motion and show that there is an additional force along the radial direction. Using Pioneer anomaly data, we set a bound for a. We also analyze the violation of equivalence principle predicted by the modified Newton's equation, valid up to first order in a and use this also to set an upper bound on a.
DYNAMICAL FERMION MASSES UNDER THE INFLUENCE OF KALUZA–KLEIN FERMIONS AND A BULK ABELIAN GAUGE FIELD
Authors: EBERT D. , ZHUKOVSKY V. CH. , TYUKOV A. V.
Published: November 2010

The dynamical fermion mass generation on the 3-brane in the 5D spacetime is discussed in a model with bulk fermions in interaction with fermions on the branes assuming the presence of a constant Abelian gauge field A5 in the bulk. We calculate the effective potential as a function of the fermion masses and the gauge field A5. The masses can be found from the stationarity condition for the effective potential (the gap equation). We formulate the equation for the mass spectrum of the 4D-fermions. The phases with finite and vanishing fermion masses are studied and the dependence of the masses on the radius of the fifth dimension is analyzed. The influence of the A5-gauge field on the symmetry breaking is considered both when this field is a background parameter and a dynamical variable. The critical values of the A5 field, the coupling constant and the radius are examined.
QUANTUM GRAVITY, DYNAMICAL ENERGY–MOMENTUM SPACE AND VACUUM ENERGY
Authors: CHANG LAY NAM , MINIC DJORDJE , TAKEUCHI TATSU
Published: November 2010

We argue that the combination of the principles of quantum theory and general relativity allow for a dynamical energy–momentum space. We discuss the freezing of vacuum energy in such a dynamical energy–momentum space and present a phenomenologically viable seesaw formula for the cosmological constant in this context.
A COVERING PROJECTION FOR ROBOT NAVIGATION UNDER STRONG ANISOTROPY
Authors: ANGHINOLFI ANDREA , COSTA LUCA , FERRI MASSIMO , VIARANI ENRICO
Published: November 2010

Path planning can be subject to different types of optimization. Some years ago a German researcher, U. Leuthäusser, proposed a new variational method for reducing most types of optimization criteria to one and the same: minimization of path length. This can be done by altering the Riemannian metric of the domain, so that optimal paths (with respect to whatever criterion) are simply seen as shortest. This method offers an extra feature, which has not been exploited so far: it admits direction–dependent criteria.

In this paper we make this feature explicit, and apply it to two different anisotropic settings. One is that of different costs for different directions: E.g. the situation of a countryside scene with ploughed fields. The second is dependence on oriented directions, which is called here "strong" anisotropy: the typical scene is that of a hill side. A covering projection solves the additional difficulty. We also provide some experimental results on synthetic data.
CONSTRAINED POINT-SET EMBEDDABILITY OF PLANAR GRAPHS
Authors: DI GIACOMO EMILIO , DIDIMO WALTER , LIOTTA GIUSEPPE , MEIJER HENK , WISMATH STEPHEN K.
Published: November 2010

This paper starts the investigation of a constrained version of the point-set embed-dability problem. Let G = (V,E) be a planar graph with n vertices, G′ = (V′,E′) a subgraph of G, and S a set of n distinct points in the plane. We study the problem of computing a point-set embedding of G on S subject to the constraint that G′ is drawn with straight-line edges. Different drawing algorithms are presented that guarantee small curve complexity of the resulting drawing, i.e. a small number of bends per edge. It is proved that:

• If G′ is an outerplanar graph and S is any set of points in convex position, a point-set embedding of G on S can be computed such that the edges of E\E′ have at most 4 bends each.

• If S is any set of points in general position and G′ is a face of G or if it is a simple path, the curve complexity of the edges of E\E′ is at most 8.

• If S is in general position and G′ is a set of k disjoint paths, the curve complexity of the edges of E \ E′ is O(2k).
LOCATING GUARDS FOR VISIBILITY COVERAGE OF POLYGONS
Authors: AMIT YOAV , MITCHELL JOSEPH S. B. , PACKER ELI
Published: November 2010

We propose heuristics for visibility coverage of a polygon with the fewest point guards. This optimal coverage problem, often called the "art gallery problem", is known to be NP-hard, so most recent research has focused on heuristics and approximation methods. We evaluate our heuristics through experimentation, comparing the upper bounds on the optimal guard number given by our methods with computed lower bounds based on heuristics for placing a large number of visibility-independent "witness points". We give experimental evidence that our heuristics perform well in practice, on a large suite of input data; often the heuristics give a provably optimal result, while in other cases there is only a small gap between the computed upper and lower bounds on the optimal guard number.
FLOWS OF VISCOUS COMPRESSIBLE FLUIDS UNDER STRONG STRATIFICATION: INCOMPRESSIBLE LIMITS FOR LONG-RANGE POTENTIAL FORCES
Authors: FEIREISL EDUARD
Published: November 2010

We study the singular limit of the compressible Navier–Stokes system in the whole space ℝ3, where the Mach number and Froude number are proportional to a small parameter ε → 0. The central issue is the local decay of the acoustic energy proved by means of the RAGE theorem. The result is quite general and the proposed approach can be applied to a large variety of problems that concern propagation of acoustic waves in compressible fluids. In particular, the method can be used for showing stability of various numerical schemes based on the so-called hybrid methods.
THE DYNAMIC PISTON PROBLEM IN CLASSICAL NONLINEAR ACOUSTICS
Authors: SAUER NIKO
Published: November 2010

This paper discusses the effects of an applied external force on the motion of a piston in a tube and the motion of the gas in the tube. The equations under consideration are the recently proposed ones for nonlinear sonic disturbances in an isentropic gas.
Behavioral Targeting
Authors: Chen Ye , Pavlov Dmitry , Canny John F.
Published: November 2010

Behavioral targeting (BT) leverages historical user behavior to select the ads most relevant to users to display. The state-of-the-art of BT derives a linear Poisson regression model from fine-grained user behavioral data and predicts click-through rate (CTR) from user history. We designed and implemented a highly scalable and efficient solution to BT using Hadoop MapReduce framework. With our parallel algorithm and the resulting system, we can build above 450 BT-category models from the entire Yahoo’s user base within one day, the scale that one can not even imagine with prior systems. Moreover, our approach has yielded 20% CTR lift over the existing production system by leveraging the well-grounded probabilistic model fitted from a much larger training dataset.

Specifically, our major contributions include: (1) A MapReduce statistical learning algorithm and implementation that achieve optimal data parallelism, task parallelism, and load balance in spite of the typically skewed distribution of domain data. (2) An in-place feature vector generation algorithm with strict linear-time complexity
O
(
n
) regardless of the granularity of sliding target window. (3) An in-memory caching scheme that significantly reduces the number of disk IOs to make large-scale learning practical. (4) Highly efficient data structures and sparse representations of models and data to enable fast model updates. We believe that our work makes significant contributions to solving large-scale machine learning problems of industrial relevance in general. Finally, we report comprehensive experimental results, using industrial proprietary codebase and datasets.