The training process： Planning for strength-power training in track and field. Part 2： Practical and applied aspects

Planning training programs for strength-power track and field athletes require an understanding of both training principles and training theory. The training principles are overload, variation, and specificity. Each of these principles must be incorporated into an appropriate system of training. Conceptually, periodization embraces training principles and offers advantages in planning, allowing for logical integration and manipulation of training variables such as exercise selection, intensification, and volume factors. The adaptation and progress of the athlete is to a large extent directly related to the ability of the coach/athlete to create and carry an efficient and efficacious training process. This ability includes： an understanding of how exercises affect physiological and performance adaptation （i.e., maximum force, rate of force development, power, etc.）, how to optimize transfer of training effect ensuring that training exercises have maximum potential for carryover to performance, and how to implement programs with variations at appropriate levels （macro, meso, and micro） such that fatigue management is enhanced and performance progress is optimized.

The training process： Planning for strength-power training in track and field. Part 1： Theoretical aspects

The process of strength-power training and the subsequent adaptation is a multi-factorial process. These factors range from the genetics and morphological characteristics of the athlete to how a coach selects, orders, and doses exercises and loading patterns. Consequently, adaptation from these training factors may largely relate to the mode of delivery, in other words, programming tactics. There is strong evidence that the manner and phases in which training is presented to the athlete can make a profound difference in performance outcome. This discussion deals primarily with block periodization concepts and associated methods of programming for strength-power training within track and field. 2015 Production and hosting by Elsevier B.V. on behalf of Shanghai University of Sport.

Multi-Object Tracking Based on Segmentation and Collision Avoidance

An approach to track multiple objects in crowded scenes with long-term partial occlusions is proposed. Tracking-by-detection is a successful strategy to address the task of tracking multiple objects in unconstrained scenarios,but an obvious shortcoming of this method is that most information available in image sequences is simply ignored due to thresholding weak detection responses and applying non-maximum suppression. This paper proposes a multi-label conditional random field（ CRF） model which integrates the superpixel information and detection responses into a unified energy optimization framework to handle the task of tracking multiple targets. A key characteristic of the model is that the pairwise potential is constructed to enforce collision avoidance between objects,which can offer the advantage to improve the tracking performance in crowded scenes. Experiments on standard benchmark databases demonstrate that the proposed algorithm significantly outperforms the state-of-the-art tracking-by-detection methods.

Common Sports Injuries and Preventive Measures for Athletes—Take The Track and Field Team Athletes in Yushan County as an Example

Taking the common sports injuries and preventive measures of Yushan County middle school track and field athletes as the research object,the sports injuries of Yushan County middle school track and field athletes were investigated and analyzed from the angle,type,location and nature of sports injury.Research on sports injury problems,trying to find the causes of sports injuries in daily training of track and field athletes,and proposed targeted preventive measures based on the specific situation of Yushan County Middle School.The results show that 77.70%of track and field athletes have suffered sports injury and periostitis and ligament/muscle strains are the most common forms of injury,and lower limbs are more prone to sports injuries than upper limbs.

Discussion on the Core Strength Training Method for 100-Meter Event in Track and Field Sports

In track and field sports,the 100-meter race is an extremely intense sport that requires effective training of athletes’core strength.From the perspective of adolescents,in order to enhance core strength,it is necessary to effectively fix the pelvic position in the process of exercise,so that the core stability,balance,and coordination of athletes can be improved.The training process of the 100-meter event is mainly an anaerobic metabolic exercise,it is necessary to ensure that athletes maintain a high level of physical readiness during the exercises and concentrate highly on their core strength,so that they can achieve excellent results.This paper analyzes the core strength training for the 100-meter event in track and field sports,discusses its importance,and puts forward specific training methods,hoping to provide guidelines for relevant researchers.

Physical activity and cardiometabolic risk factors in sprint and jump-trained masters athletes,young athletes and non-physically active men

Objectives Assessing physical activity and cardiometabolic risk in masters athletes as an example of very high physical activity at old age.Methods Forty-three men were studied in full factorial design,either as sprint or jump-trained masters athletes(MA,n=10,age 60–75 years),as young sprint or jump-trained athletes(YA,n=10,age 20–35 years),older control participants(OC,n=11,age 60–75 years)or as young control participants(AC,n=12,age 20–35 years).We performed bio-electrical impedance analysis and assessed serum markers of lipids and glucose metabolism and C-reactive protein,structured training hours,and habitual activity via mobile actimetry.Results Body fat was greater in OC than in MA(23.9[SD 4.2]%vs.14.0[SD 5.7]%,p<0.001),and also greater than in YA and YC(both p<0.001).Weekly training hours were comparable between MA and YA(7.9[SD3.3]hours vs.11.1[SD 4.8]hours,p=0.69).Habitual walking distance was greater in MA than in OC(7,387[SD 4,923]m/day vs.4,110[SD 1,772]m/day,p=0.039),and so was habitual running distance(667[SD690]m/day vs.132[427]m/day,p<0.001).HOMA-index was greater in OC than in MA(2.07[SD 1.39]vs.0.80[SD 0.41],p=0.0039),and so was C-reactive protein(1.35[SD 1.74]mg/l vs.0.58[SD 0.27]mg/ml,p=0.018),whereas serum lipids showed only moderate or no effect(all p between 0.036 and 0.07).Conclusions Improved body composition and physical activity levels in MA are associated with lower cardiometabolic risk,which seems more pronounced for insulin sensitivity and inflammaging than for lipid metabolism.

A GOCE only gravity model GOSG01S and the validation of GOCE related satellite gravity models

We compile the GOCE-only satellite model GOSG01S complete to spherical harmonic degree of 220 using Satellite Gravity Gradiometry （SGG） data and the Satellite-to-Satellite Tracking （SST） observations along the GOCE orbit based on applying a least-squares analysis. The diagonal components （Vxx, Vyy, Vzz） of the gravitational gradient tensor are used to form the system of observation equations with the band-pass ARMA filter. The point-wise acceleration observations （ax, ay, az） along the orbit are used to form the system of observation equations up to the maximum spherical harmonic degree/order 130. The analysis of spectral accuracy characteristics of the newly derived gravitational model GOSG01S and the existing models GOTIM04S, GODIR04S, GOSPW04S and JYY_GOCE02S based on their comparison with the ultrahigh degree model EIGEN-6C2 reveals a significant consistency at the spectral window approximately between 80 and 190 due to the same period SGG data used to compile these models. The GOCE related satellite gravity models GOSG01S, GOTIM05S, GODIR05S, GOTIM04S, GODIR04S, GOSPW04S, JYY_- GOCE02S, EIGEN-6C2 and EGM2008 are also validated by using GPS-leveling data in China and USA. According to the truncation at degree 200, the statistic results show that all GGMs have very similar differences at GPS-leveling points in USA, and all GOCE related gravity models have better performance than EGM2008 in China. This suggests that all these models provide much more information on the gravity field than EGM2008 in areas with low terrestrial gravity coverage. And STDs of height anomaly differences in China for the selected truncation degrees show that GOCE has improved the accuracy of the global models beyond degree 90 and the accuracies of the models improve from 24 cm to 16 cm. STDs of geoid height differences in USA show that GOSG01S model has best consistency comparing with GPSleveling data for the frequency band of the degree between 20 and 160.

The relationship between steeplechase hurdle economy, mechanics, and performance

Background： Research surrounding the steeplechase is scarce, with most research focusing primarily on how biomechanical factors relate to maintaining running speed while crossing barriers. One area that has not been well explored is the relationship between biomechanical factors and hurdling economy. The purpose of this study was to investigate how pel：formance times and biomechanical variables relate to hurdling economy during the steeplechase. Methods： This was accomplished by measuring running economy of collegiate and professional steeplechasers while rmming with and without hurdles. Biomechanical measures of approach velocity, takeoff distance, clearance height, and lead knee extension while hurdling, as well as steeplechase performance times were correlated to a ratio of running economy with and without hurdles. Results： While oxygen uptake was 2.6% greater for the laps requiring five barriers, there was no correlation between steeplechase performance time and the ratio of running economy during the hurdle and non-hurdle laps. Results also indicated no correlation between the aforementioned biomechanical variables and ratio of running economy during the hurdle and non-hurdle laps. Conclusion： Increasing approach velocity did not negatively affect running economy. Increased approach velocity is a benefit for maintenance of race pace, but does not hurt economy of movement.

Study on the effects of chromaticity and magnetic field tracking errors at CSNS/RCS

The Rapid Cycling Synchrotron （RCS） is a key component of the China Spallation Neutron Source （CSNS）. For this type of high intensity proton synchrotron, the chromaticity, space charge effects, and magnetic field tracking errors between the quadrupoles and the dipoles can induce beta function distortion and tune shift, and induce resonances. In this paper, the combined effects of chromaticity, magnetic field tracking errors and space charge on beam dynamics at CSNS/RCS are studied systemically. 3-D simulations with different magnetic field tracking errors are performed by using the code ORBIT, and the simulation results are compared with the case without tracking errors.

Analysis and mitigation of bump magnetic field tracking errors in a multiturn injection system

Purpose The Space Environment Simulation and Research Infrastructure(SESRI)is a cluster of accelerators designed to simulate the cosmic radiation environment by generating particles of various types and energies.Among these accelerators,a synchrotron in the 300 MeV proton and heavy ion accelerator complex utilizes a multiturn injection scheme with four bump magnets to accumulate proton and heavy ion beams effectively.However,the bump magnetic field experiences a rapid drop rate of up to 1000 T/s,inevitably leading to a deviation(field tracking error)from the ideal magnetic field.The injection efficiency and particle distribution are significantly affected by this field tracking error,as evaluated by the ACCSIM code.Method During the device testing stage,the sources of field tracking errors were identified by analysis of the bump power supplies and the field of the magnets.Mitigation techniques were then implemented to reduce the field tracking error from[Math Processing Error]to[Math Processing Error]throughout the entire power supply,transmission cable,and magnet chain.Results Moreover,the successful injection and accumulation of beams during the operational phase of the synchrotron confirmed the effectiveness of the proposed mitigation methods.Additionally,a magnetic field measurement system was developed to monitor the magnetic field tracking error online.Conclusion The combination of the field tracking error mitigation methods and the measurement system provides valuable guidance for optimizing the magnetic fields with rapid drop rates.

Prolonged Intermittent Running Induces Inspiratory-Muscle Fatigue in Female Runners

Inspiratory-muscle fatigue （IMF） may occur after long-duration or continuous short-duration exercise and may limit exercise performance. Daily athletics training is often intermittent, but it is unclear if intermittent running induces IMF. We investigated IMF after a maximal anaerobic running test （MART） and maximal intermittent graded exercise test. Nine female middle-distance （400 or 800 m） runners performed MART and maximal intermittent graded exercise tests. Maximal inspiratory pressure （MIP） was measured before and after each test using a portable autospirometer. There was no significant difference in mean MIPs before （105 ± 24 cm H2O） and after （104 ± 28 cm H2O） the MART （P = 0.95, effect size [ES] as partial η2 = 0.01）. Mean M IP after the maximal intermittent graded exercise test （97 ± 26 cm H2O） was lower than before exercise （105 ± 27 cm H2O） （P = 0.01, 1]2 = 0.83） Mean IMF was higher for the maximal intermittent graded exercise test （8.5 ± 4.2 cm H2O） than for the MART （0.8 ± 4.1 cm H2O） （P = 0.01, ES as Cohen＇s d = 1.88）. IMF occurs after relatively long-duration intermittent running exercise. Coaches may consider recommending inspiratory-muscle training or warm-up to reduce IMF resulting from relatively long-duration intermittent running exercise.

Relationships Between Vertical Jump Metrics and Sprint Performance,and Qualities that Distinguish Between Faster and Slower Sprinters

Purpose This study aimed to investigate the relationships between vertical jump metrics and phases during a 60 m sprint.The variances in strength qualities between sprinters of different ability levels were also compared.Methods Eighteen young male elite sprinters(age:18.1±1.3 years;stature:1.72±0.07 m;body mass:66.3±6.2 kg)were assessed for squat(SJ),countermovement(CMJ),drop(DJ),and standing long jumps,a maximal load back-squat,and a 60-m sprint from a block-start.The relationships between sprint performances with all variables were analysed using correlation and multiple regression while discriminative parameters between fast(100 m time:~10.50 s)and slow(~11.00 s)sprint groups were assessed using independent t-tests.Results Higher associations existed between vertical jumps and longer sprint distances,especially between SJ height and relative peak power with 10 m(r=−0.47 and−0.47,respectively),30 m(−0.71 and−0.74),60 m(−0.76 and−0.81),10-30 m(−0.80 and−0.86),and 30-60 m(−0.78 and−0.84)sprint distances.Concurrently,variables such as relative maximal-strength,relative SJ parameters(height,peak force,and peak power),relative CMJ peak power,and reactive strength index(DJ from 35 cm height)had significant discriminative ability and correlations(P<0.05)with sprint distances involving maximal velocity and flying-start.Additionally,a combination of SJ height and relative maximal-strength during back-squat accounted for 75%of the variance in 60 m sprint times.Conclusions Relative measures of multiple strength metrics may provide better insight regarding factors that enhance sprint performance.Adequate maximal-strength,high explosive power,and reactive strength seem necessary to improve sprint performance in young male elite sprinters.

The frequency and performance trends of European countries in the U18 and U20 rankings for 1500 m and 3000 m between 2009-2020

We purpose to determine the nationality of the European middle-distance athletes under 18 years(U18)and under 20 years(U20)during the last decade,to verify the participation trend for each country,and to assess whether the place of competition can be associated with the athletes ranking position.The sample comprised 902 European male runners,ranked among the best finishers from 2009 to 2020.The athletes were divided into two categories(n_(U18)=266;and n_(U20)=636)of two distances(n_(1500m)=397;n_(3000m)=505).The Mantel test was used for participation trend and the Chi-square test(χ^(2))was used to verify differences between the ranking position and the place of competition.For both distances,the highest number of athletes were from Spain(n=127),followed by Turkey(n=62)and Great Britain(n=50).No significant trends were shown for most of the countries,in both distances.A positive trend was shown for Slovenia(i.e.,3000m)over the years.A non-significant association was verified between the countries and the ranking position,as non-significant differences were proved for the place of competition.This information may be useful to guide athlete development programs in each country.