Heavy-load Training Research Articles

The Wheel–Rail Contact Force for a Heavy-Load Train Can Be Measured Using a Collaborative Calibration Algorithm

The wheel–rail contact force is a crucial indicator for ensuring the secure operation of a heavy-load train. However, obtaining the real-time wheel–rail contact force of a heavy-load train is a challenging task as, due to safety considerations, it is not possible to install instrumented wheelsets on heavy-load trains. This work presents a novel approach to quantify the wheel–rail contact force of a heavy-load train, utilizing a cooperative calibration methodology. First, a ground measurement platform for the wheel–rail contact force of a heavy-load train is constructed on a selected rail section. The railway inspection car’s wheel–rail contact force measurement system is fine-tuned using a multilayer perceptron calibration approach, and the ground platform then uses the results to fine-tune the railway inspection car’s examined wheelset. Second, based on actual measured data on the wheel–rail contact force of a heavy-load train, and using the golden jackal optimization algorithm, the multilayer perceptron correction approach is employed to create a data relationship mapping model. This model correlates the corrected data on the wheel–rail contact force obtained from the railway inspection car with the wheel–rail contact force of a heavy-haul train with an axle load of 25 tons, and the precision of the mapping is guaranteed. Finally, by combining the wheel–rail contact force correction method for the railway inspection car and the contact force mapping model between the railway inspection car and the heavy-load train, collaborative calibration of the wheel–rail contact force of the heavy-load train is realized. The experimental results under two working conditions show that this method can realize high-precision, real-time measurement of the wheel–rail contact force of a heavy-load train. For the working condition of a straight-line section, the calibration error was within 1.593 kN, and the MAPE was 0.105%; for the working condition of a curved-line section, the calibration error was 2.344 kN, and the RMSE was 184.72 N.

Research on Innovative Mode of Preventing Train Derailment Under Emergency Braking Condition of Super-Long Heavy-Load Train

After many years of operation practice and academic research, the author found that after the 1800 meter long heavy haul train had emergency braking, the dangerous "vehicle lifting and squeezing moment" was transferred from the head to the tail of the train one by one, which was called "wall collision effect" in the passenger service; Especially for combined trains, the phenomenon of vehicle lifting and squeezing is particularly obvious, Especially for combined trains, the phenomenon of vehicle lifting and squeezing is particularly obvious, and the derailment probability of locomotives in the middle increases greatly, which seriously threatens the operation safety of overlong heavy haul In this paper, the author boldly breaks through the traditional thinking and creatively puts forward a new idea that the braking torque of super long heavy haul train transforms the existing extrusion emergency braking parking from the front to the back should be generated the more safe " stretching state" parking from the rear stretching state" parking from the rear to the front, changing the transmission direction of the braking torque from "front to back" to "back to front", which greatly reduces the derailment coefficient of the super long heavy haul train under the emergency braking condition.

The use of blood flow restriction does not enhance adaptations of corticospinal excitability or intracortical inhibition after acute resistance training

Resistance exercise with blood flow restriction (BFR) is considered a safe and powerful training tool. Low-load (LL) resistance training with BFR results in comparable hypertrophy compared to conventional heavy-load (HL) resistance training (Centner et al., 2019). Additionally, LL training with BFR (LL-BFR) induces comparable (Grønfeldt et al., 2020) or slightly lower (Centner et al., 2019) effects on muscle strength than HL training. It is generally accepted that increases in maximum strength are mediated by muscular hypertrophy and/or neural adaptations. However, the effect of BFR on neural adaptations is scarcely investigated. The aim of this study was therefore to investigate the effects of BFR on acute neural adaptations following a single bout of resistance training.
 Fifteen male participants (21-35 years) volunteered to participate in this study. On three separate days, participants performed a strength training session of the right elbow flexors with either LL, LL-BFR or HL. Neuromuscular adaptations were investigated before and after each resistance training session by means of transcranial magnetic stimulation (single- and paired-pulse TMS) and peripheral nerve stimulation (Mmax). Data were acquired during submaximal sustained isometric contractions. During LL-BFR, the cuff was inflated to 50% of the individual arterial occlusion pressure to restrict venous outflow in the working musculature during exercise.
 The preliminary data analysis with mixed linear models revealed that, compared to baseline values, normalized MEPs (% of Mmax) from the trained biceps brachii were enhanced for HL (Cohen’s d = 0.51) but not LL-BFR (Cohen’s d = 0.03) when compared to LL. None of the groups showed relevant changes in short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). The size of Mmax decreased slightly for HL (Cohen’s d = -0.18) but not LL-BFR (Cohen’s d = 0.06) when compared to LL.
 This is the first study that investigated acute neural adaptations in response to resistance training with and without BFR. We observed increased MEP amplitudes after HL but not LL what is in line with previous evidence (Mason et al., 2019). Since training with BFR results in a rapid increase in motoneuronal excitability (Copithorne et al., 2020), the increased MEP are less likely caused by changes at the cortical site.
 Centner, C., Wiegel, P., Gollhofer, A., & König, D. (2019). Effects of blood flow restriction training on muscular strength and hypertrophy in older individuals: A systematic review and meta-analysis. Sports Medicine, 49, 95-108. https://doi.org/10.1007/s40279-018-0994-1
 Copithorne, D. B., Rice, C. L., & McNeil, C. J. (2020). Effect of blood flow occlusion on corticospinal excitability during sustained low-intensity isometric elbow flexion. Journal of Neurophysiology, 123(3), 1113-1119. https://doi.org/10.1152/jn.00644.2019
 Grønfeldt, B. M., Lindberg Nielsen, J., Mieritz, R. M., Lund, H., & Aagaard, P. (2020). Effect of blood-flow restricted vs heavy-load strength training on muscle strength: Systematic review and meta-analysis. Scandinavian Journal of Medicine & Science in Sports, 30(5), 837-848. https://doi.org/10.1111/sms.13632
 Mason, J., Howatson, G., Frazer, A. K., Pearce, A. J., Jaberzadeh, S., Avela, J., & Kidgell, D. J. (2019). Modulation of intracortical inhibition and excitation in agonist and antagonist muscles following acute strength training. European Journal of Applied Physiology, 119, 2185-2199. https://doi.org/10.1007/s00421-019-04203-9

Study on Mechanism and Influencing Factors of Wheel Strengthening and Toughening of High-Speed and Heavy-Load Train

When maximum speed of 160 km/h is reached and the axle load reaches 25–30 tons, the train wheels need to have high strength and toughness. The main chemical elements affecting the strength and toughness of the wheel were determined by the mechanical features of the samples with different chemical compositions. Through analysis of the impact fracture of typical specimens, the difference of wheel toughness was mainly reflected in the dimple band, crack source, and cleavage pattern. By SEM analysis of fracture cracks, the critical size difference was found to exist between the grains during brittle fracture, where the intergranular fracture between grains of different sizes is mainly due to the different interfacial stresses between grains of different sizes.

Blood Flow Restriction Training for Tendinopathy Rehabilitation: A Potential Alternative to Traditional Heavy-Load Resistance Training

Tendinopathy is a chronic tendon disease which can cause significant pain and functional limitations for individuals, and which collectively places a tremendous burden on society. Resistance training has long been considered the treatment of choice in the rehabilitation of chronic tendinopathies, with both eccentric and heavy slow resistance training demonstrating positive clinical effects. The application of progressive tendon loads during rehabilitation is essential to not compromise tendon healing, with the precise dosage parameters of resistance training and external loading a critical consideration. Blood-flow restriction training (BFRT) has become an increasingly popular method of resistance training in recent years and has been shown to be an effective method for enhancing muscle strength and hypertrophy in healthy populations and in musculoskeletal rehabilitation. Traditional resistance training for tendinopathy requires the application of heavy training loads, whereas BFRT utilises significantly lower loads and training intensities, which may be more appropriate for certain clinical populations. Despite evidence confirming the positive muscular adaptations derived from BFRT and the clinical benefits found for other musculoskeletal conditions, BFRT has received a dearth of attention in tendon rehabilitation. Therefore, the purpose of this narrative review was threefold: firstly, to give an overview and analysis of the mechanisms and outcomes of BFRT in both healthy populations and in musculoskeletal rehabilitation. Secondly, to give an overview of the evidence to date on the effects of BFRT on healthy tendon properties and clinical outcomes when applied to tendon pathology. Finally, a discussion on the clinical utility of BFRT and its potential applications within tendinopathy rehabilitation, including as a compliment to traditional heavy-load training, is presented.

Heavy-load train model based on RBF neural network refers to the adaptive brake control strategy

Heavy-load train braking control is an important automatic driving function. The braking mode mainly used in China is air braking, which has great nonlinear characteristics. In order to reduce the influence of system uncertainty on control, improve the control accuracy and ensure the safety and efficiency of train transportation, an adaptive brake control strategy is designed.Firstly, establish the state space model of braking system according to the dynamic process of overloaded train braking, use the adaptive method and design the RBF model to track the train speed. Finally, the actual data from CK1466.1 to CK1431.3 in the line is used as the reference model. Experimental results The RBF neural network model designed by the reference adaptive controller realizes the tracking control of a given speed curve with high accuracy, verifying the effectiveness of the strategy.

Multisign Health Monitoring Technology of Athletes Based on Artificial Intelligence

In order to improve the monitoring efficiency of physical fitness characteristics of athletes in training state, this paper proposes the research on athletes’ multisign health monitoring technology based on artificial intelligence sensor technology. Taking six excellent boxers as the experimental objects, four weeks of heavy load training and 10 training courses per week were arranged from six weeks before the competition to two weeks before the competition. The 4-week training is divided into two stages. From the first week to the fourth week, the training amount remains unchanged and the training intensity increases. The artificial intelligence sensor technology is used to design the athlete training state pulse test system. The athlete training state pulse sensor is responsible for collecting the athlete training state pulse data. The athlete pulse sensor in this system adopts zn17-kg200 pulse vibration sensor as the pulse sampling sensor. After 4 weeks of heavy load training, before and after adjusting for rest, venous blood was taken fasting on the next morning. White blood cells (WBC), red blood cells (RBC), hemoglobin (hemoglobin, Hb), testosterone (hemoglobin, H), cortisol (cortisol), and testosterone/cortisol ratio were measured. The experimental results showed that T and T / C of athletes were significantly lower than those before training ( P < 0.01 ), 37.99% and 52.69%, respectively. C and morning pulse were significantly higher than those before training ( P < 0.05 ), with an increase range of 32.39% and 20.39%. There was no statistical significance in the changes of WBC, RBC, and Hb. HRV indexes lnLF and LF/HF were significantly higher than those before training. Athletes carry the designed portable athlete training state pulse test for heavy load training and display the current training state pulse data of each athlete in real time. The experimental data show that the system designed in this paper can monitor the pulse information of athletes in the training state in real time. The monitoring has good real-time result and accuracy and can realize the abnormal pulse alarm, which has a certain practical value.

Muscle Adaptations to Heavy-Load and Blood Flow Restriction Resistance Training Methods.

Resistance-based blood flow restriction training (BFRT) improves skeletal muscle strength and size. Unlike heavy-load resistance training (HLRT), there is debate as to whether strength adaptations following BFRT interventions can be primarily attributed to concurrent muscle hypertrophy, as the magnitude of hypertrophy is often minor. The present study aimed to investigate the effect of 7 weeks of BFRT and HLRT on muscle strength and hypertrophy. The expression of protein growth markers from muscle biopsy samples was also measured. Male participants were allocated to moderately heavy-load training (HL; n = 9), low-load BFRT (LL + BFR; n = 8), or a control (CON; n = 9) group to control for the effect of time. HL and LL + BFR completed 21 training sessions (3 d.week−1) comprising bilateral knee extension and knee flexion exercises (HL = 70% one-repetition maximum (1-RM), LL + BFR = 20% 1-RM + blood flow restriction). Bilateral knee extension and flexion 1-RM strength were assessed, and leg muscle CSA was measured via peripheral quantitative computed tomography. Protein growth markers were measured in vastus lateralis biopsy samples taken pre- and post the first and last training sessions. Biopsy samples were also taken from CON at the same time intervals as HL and LL + BFR. Knee extension 1-RM strength increased in HL (19%) and LL + BFR (19%) but not CON (2%; p < 0.05). Knee flexion 1-RM strength increased similarly between all groups, as did muscle CSA (50% femur length; HL = 2.2%, LL + BFR = 3.0%, CON = 2.1%; TIME main effects). 4E-BP1 (Thr37/46) phosphorylation was lower in HL and LL + BFR immediately post-exercise compared with CON in both sessions (p < 0.05). Expression of other growth markers was similar between groups (p > 0.05). Overall, BFRT and HLRT improved muscle strength and size similarly, with comparable changes in intramuscular protein growth marker expression, both acutely and chronically, suggesting the activation of similar anabolic pathways. However, the low magnitude of muscle hypertrophy was not significantly different to the non-training control suggesting that strength adaptation following 7 weeks of BFRT is not driven by hypertrophy, but rather neurological adaptation.

Analysis of Metabonomic Characteristics after Exercise Fatigue Based on NMR.

In order to better understand the changes of body metabolism of athletes before and after exercise, this paper proposes a method of metabonomics feature analysis after exercise fatigue based on NMR. This paper makes a retrospective analysis on the metabonomic characteristics of urine of middle and long distance runners after 30 minutes of a heavy load training class based on NMR. The experiment analyzes the urine of athletes by combining NMR technology and metabonomics principle. The experimental results show that the Q2 value of this experiment is greater than that of all comparisons, and r2x and r2y are 0.436 and 0.85, respectively. Conclusion. This method can effectively analyze the changes of body metabolism after athletes' fatigue, so as to better alleviate athletes' fatigue after exercise.

Review of the influence of different sports activities on preschooler’s physical fitness

Good physical fitness plays a positive role in work and life: first, it is the basis of people’s lives and work; second, it helps to master complex technical movements and improve sports performance; third, it supports heavy load training or high intensity work. In recent years, the development of sports activities can promote the improvement of preschooler’s physical quality and reduce the obesity rate and a series of physical health problems induced by obesity. At present, there are various sports activity courses in and outside kindergarten for parents and preschoolers to choose. By consulting the CNKI, Web of Science and other databases about sports intervention and preschooler’s physical fitness, this paper summarises the findings of some studies on the influence of different sports activities (including preschool football, basketball, Taekwondo, roller skating and fitness courses) on children’s physical quality in the last 10 years. The results show that different sports have different effects on the development of preschooler’s physical fitness, and each has its own focus. This paper provides some reference for the research of the related courses for preschool children in the later period. When parents plan the physical education course in combination with the actual physical activities of preschoolers, the conclusion of this review has certain practical significance.

Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum.

Loading recommendations for resistance training are typically prescribed along what has come to be known as the “repetition continuum”, which proposes that the number of repetitions performed at a given magnitude of load will result in specific adaptations. Specifically, the theory postulates that heavy load training optimizes increases maximal strength, moderate load training optimizes increases muscle hypertrophy, and low-load training optimizes increases local muscular endurance. However, despite the widespread acceptance of this theory, current research fails to support some of its underlying presumptions. Based on the emerging evidence, we propose a new paradigm whereby muscular adaptations can be obtained, and in some cases optimized, across a wide spectrum of loading zones. The nuances and implications of this paradigm are discussed herein.

Oyster peptide prevents the occurrence of exercise-hypogonadal male condition by improving the function of pituitary gonadal axis in male rats.

This study evaluates the protective role of oyster peptide (OP) on the occurrence of Exercise-Hypogonadal Male Condition. Male rats were given heavy-load swimming training and / or OP was supplemented for 6 consecutive weeks. After heavy-load training, sperm count, sperm viability and sperm motility in epididymis, testosterone in serum and testis, glutathione peroxidase (GSH-px) and androgen receptor (AR) in testis and mating times were remarkably decreased, malondialdehyde (MDA), capture latency and mating latency were significantly increased, mRNA expression of steroidogenic acute regulatory (StAR) and P450 cholesterol side-chain cleavage enzyme (P450scc) were obviously down-regulated, but serum follicle-stimulating hormone (FSH) and luteinising hormone (LH) were not statistically changed. Conversely, when OP was supplemented at heavy-load training, sperm count, sperm viability and sperm motility in epididymis, serum FSH, LH, testosterone, GSH-px, superoxide dismutase (SOD), testosterone, AR in testis and mating times were dramatically increased, while testicular MDA, capture latency and mating latency were significantly decreased, and mRNA expression of StAR, StARD7, P450scc and 3β-hydroxysteroid dehydrogenase (3β-HSD) were significantly up-regulated. In conclusion, heavy-load training causes testicular spermatogenic and steroidogenic disorders by enhancing the generation of reactive oxygen species (ROS), which can be protected by the co-administration of OP by enhancing the function of pituitary gonad axis and lowering ROS generation.

Simulation Evaluation and Analysis of Heavy-load Train Maintenance Mode Based on Petri Net

In China’s comprehensive transportation system, railway is an important mode of transportation, and heavy-load railway is a large-capacity transportation channel, which can quickly improve efficiency and relieve the capacity of railway transportation. The efficiency and synergistic capability of each connecting point of heavy-haul railway determines the success or failure of the whole system. In this paper, two different maintenance modes, “planned repair” and “unit centralized repair”, are used to discuss the turnround procedure of rolling stock and the empty wagon’s operation procedure respectively. The Petri net model of the empty wagon’s operation procedure under different maintenance modes is established, and the simulation is completed by Visual Object Net++ software. The results show that “unit centralized repair” is beneficial to compress the operation time and accelerate the turnround of rolling stock.

Mechanical Characteristics of Heavy vs. Light Load Ballistic Resistance Training in Older Adults.

Rodriguez-Lopez, C, Alcazar, J, Sánchez-Martín, C, Ara, I, Csapo, R, and Alegre, LM. Mechanical characteristics in heavy vs. light load ballistic resistance training in older adults. J Strength Cond Res 36(8): 2094-2101, 2022-Although power-oriented resistance training (RT) is strongly recommended to counter age-related neuromuscular function declines, there is still controversy about which intensities of load should be used to elicit optimal training adaptations. Knowledge of the mechanical characteristics of power-oriented RT performed at different intensities might help to better understand the training stimulus that triggers load-dependent adaptations in older adults. Using a cross-over design, 15 well-functioning older volunteers (9 men and 6 women; 73.6 ± 3.8 years) completed 2 volume × load-matched ballistic RT sessions with heavy (HL: 6 × 6 × 80% 1-repetition maximum [1RM]) and light-load (LL: 6 × 12 × 40% 1RM) on a horizontal leg press exercise. Electromyographic (EMG) and mechanical variables (work, force, velocity, and power) as well as intraset neuromuscular fatigue (i.e., relative losses in force, velocity, and power) were analyzed. More concentric mechanical work was performed in the LL training session, compared with HL (36.2 ± 11.2%; p < 0.001). Despite the higher mean EMG activity of the quadriceps femoris muscle (13.2 ± 21.1%; p = 0.038) and greater concentric force (35.2 ± 7.6%; p < 0.001) during HL, higher concentric velocity (41.0 ± 12.7%, p < 0.001) and a trend toward higher concentric power (7.2 ± 18.9%, p = 0.075) were found for LL. Relative velocity losses were similar in both sessions (≈10%); however, relative force losses were only found in LL (7.4 ± 6.5%, p = 0.003). Considering the greater mechanical work performed and concentric power generated, ballistic RT using LL may, therefore, represent a stronger stimulus driving training adaptations as compared with volume × load-matched heavy-load training. Relative losses in force and power should be monitored in addition to velocity losses during ballistic RT.

Heart rate recovery responses after acute training load changes in top-class water polo players

The purpose of the study was to investigate the effects of acute training load changes of elite water polo players on heart rate recovery (HRR) responses after a standardized swimming test. Nine water polo players were tested after a two-day light-load and two-day heavy-load training. Preliminarily, critical swimming speed was calculated. Testing comprised of an intermittent 4 × 100-m swimming separated by 10 s of rest with an intensity corresponding to 85% of their maximum speed previously attained during a 100-m swim test followed immediately by assessment of HRR. Internal training load (ITL) was measured using the rating of perceived exertion and the duration of training sessions. The swimming speed corresponded to 1.43 ± 0.06 m·s−1 and 1.45 ± 0.06 m·s−1 after light-load and heavy-load training, respectively (p = 0.06, d = 0.74). ITL was increased in high-load compared to light-load training (p < 0.001, d = 11.54). The difference in HR at end of exercise (HR-end) and after 60 s rest and the difference in mean HR during last min of exercise and HR after 60 s rest were higher in light-load training (p < 0.05, d = 0.85–1.15). The absolute change in ITL was correlated with the respective change in the percentage change of HR-end at 10 s of recovery (%HRR10s) (r = 0.72, p = 0.03). Significant correlation was observed between the percentage change of ITL with the %HRR10s (r = 0.67, p = 0.05). We conclude that HRR tracks acute changes in training load. The lower HRR following high-load training likely indicates a blunted parasympathetic re-activation.

ФАКТОРНЫЙ АНАЛИЗ РАБОТЫ ДИСТАНЦИОННОЙ ЗАЩИТЫ ФИДЕРОВ КОНТАКТНОЙ СЕТИ В УСЛОВИЯХ ОРГАНИЗАЦИИ ТЯЖЕЛОВЕСНОГО ДВИЖЕНИЯ

The paper considers a connection of factors that affect the operation of distance protection of catenary feeders. The paper also presents an assessment of this effect on operation quality and selectivity of protection in conditions of operation of heavy-load trains with the weight up to 12,000 tons on example of measurements carried out on the Zabaikal Railway.

АНАЛИЗ ПАРАМЕТРОВ И КОНСТРУКТИВНЫХ РЕШЕНИЙ КУЗОВОВ ИННОВАЦИОННЫХ ВАГОНОВ

Development strategy of railway transport envisages operation of heavy-load trains on the following directions: Kuzbass — Far East (7100 tons), Kuzbass — South, Kuzbass — Centre, Kuzbass — North-West (9000 tons). But the existing rolling stock used for coal transportation doesn’t allow making up trains with the set weight on standard length of receivingand- departure tracks in direction of Far East. That is why the designers and manufacturers of open-box cars got a task to realize a design weight-bearing capacity in the unit of the rolling stock. The task has been solved by the increase of internal dimensions of open-box car body in existing limits by changing bodies design.

PO-107 Applied Research on Heart Rate Variability in Monitoring Sports Fatigue of Boxing Athletes

Objective Based on the diagnosis of sports fatigue using physiological and biochemical indicators, to detect the changes of heart rate variability (HRV) index before and after heavy load training in boxing athletes, and observe the effect of heavy load training on cardiac autonomic nerves. The purpose of this study was to investigate the application of HRV to monitor boxing athletes’ sports fatigue.&#x0D; Methods 16 athletes from Shanghai men's boxing team were recruited. The coach organized a 4-week heavy load training, on Monday morning before and after heavy load training, to evaluate whether athletes have exercise fatigue by testing white blood cell (WBC), red blood cell (RBC), hemoglobin (Hb), blood testosterone (T), cortisol (C), testosterone/cortisol ratio (T/C), creatine kinase (CK), blood urea (BU) and morning pulse. Heart rate variability (HRV) indicators were detected simultaneously. The data were analyzed by SPSS 19.0 statistical software. Pearson correlation analysis was used to compare the correlation between HRV and physiological and biochemical indexes. The paired sample T test was used to compare the differences between the indicators, P&lt;0.05, P&lt;0.01 was statistically significant.&#x0D; Results After heavy load training, when compared with indexes before heavy load training, T and T/C ratios decreased significantly (-38%, -52.7%, p&lt;0.01), C and morning pulse increased significantly (+32.4%, +20.4%, p&lt;0.05), BU and CK had an increasing trend but no statistical significance (+16.5%, +52.7%, p&gt;0.05), while WBC, RBC and Hb showed no statistical significance (p&gt;0.05), these changes in physiological and biochemical indexes can diagnose sports fatigue of boxing athletes after heavy load training. SDNN of HRV index was significantly correlated with morning pulse (p&lt;0.05), RMSSD was significantly correlated with CK (p&lt;0.05), LF was significantly correlated with Hb (p&lt;0.05), and LF/HF was significantly correlated with T, C, T/C, morning pulse, CK (p&lt;0.05). After heavy load training, LF and LF/HF of HRV index in boxing athletes were significantly increased than that before heavy load training (1744.7±1526.3 ms2 vs. 1134.5±1003.3 ms2, 2.5±1.3 vs. 1.6±1.0, p&lt;0.05), the other HRV indexes showed no statistical significance (p&gt;0.05).&#x0D; Conclusions The LF and LF/HF changed significantly when boxing athletes appeared sports fatigue, suggesting that the sympathetic nervous system had enhanced activity and increased tension, the imbalance between Sympathetic and parasympathetic tend to predominate in sympathetic activity. LF and LF/HF are sensitive HRV indicators for monitoring sports fatigue in boxing athletes.

PL-004 Research on monitoring power endurance training effect of synchronized swimmers

Objective To explore the usage of heart rate and derivative index, such as quick recovery index (QRI) and training impulse (TRIMP), to monitor and evaluate load level at physical training course. With simplified load evaluation program, we can accurately feedback load stress and recovery conditions of the athletes, so as to timely adjust training load and avoid sports fatigue.&#x0D; Methods Maximum oxygen uptake is tested to determine maximum heart rate of the athletes, which can be used as the basis for monitoring assessment of physical training load. During training phase, monitoring the variation of the relative index of HR and sleeping conditions of 10 athletes by Firstbeat. The test means was High-intensity interval endurance of climbing machine in 7*20s-20s before and after stage training. The main indexes include of QRI/TRIMP/EPOC/BLa\climbing height. &#x0D; Results It’s shown through monitoring that maximum heart rate of the athletes in the physical training course is up to 200BPM, which prompts high load level during training. Such athletic ability is promoted to satisfy the demands for complex choreography. Characteristics of energy supply for power endurance with high intensity closely agree with physical fitness demand during synchronized swimming competition, which is general performance of strength, speed and endurance. Through comparison of data on testing power endurance of climbing machine in 7*20s-20S before and after training, average climbing height of the athletes is increased from 60.1m/20s to 62.4m/20s with increased range up to 3.8% and blood lactate level is decreased from 10.7mmol/L to 10.5mmol/L in 2 minutes after exercise, which can be regarded as slightly improvement of ability of the athletes for lactate decomposition and fatigue relief, and aerobic capacity of the athletes are improved to a certain degree. After training, heart rate QRI and TRIMP of the athletes are improved slightly. Among them, QRI is significantly improved from 19.6% to 21.6% after stage training, which shows slightly improvement of training quality and recovery capability of the athletes, i.e. adaptive capacity to training load; After physical training, research on monitoring QRI of the athletes during arrangement and relaxation shows that maximum heart rate level without voice guidance is 75.1bpm,which is higher than those with voice guidance 72.9bmp after 5-min quick recovery; QRI of the athletes is 31.9% when voice is used to guide relaxation, which is significantly higher than those without relaxation under voice guidance (QRI is 27.0%); night pressure monitoring unit (BodyGuard2) of Firstbeat is used to monitor sleeping conditions of the athletes. In the initial stage of heavy load training cycle, training load enables athletes to produce a strong stress response, which causes relatively poor sleeping and recovery conditions; with gradual adaptation of the athletes to the training load, in the middle and later stages of the cycle, stress response of the athletes during sleeping almost disappears, and their sleeping quality and recovery conditions are improved significantly. &#x0D; Conclusions Through Power endurance training, lactate elimination capacity of the athletes, i.e. anti-fatigue capacity and quick recovery capability are improved; during quick recovery of the athletes, voice guidance can be used to effectively promote quick recovery of the athletes. Exercise heart rate, TRIMP and QRI can be used to perceptually and rapidly monitor completion of physical training load in a real-time way, Objective to evaluate recovery and sleeping conditions of the athletes, and effectively evaluate high-intensity interval physical training load and training effect.

Dynamic Responses of 87-Type Railway Steel Beam for Rush-repair under Heavy Load Trains

87-type railway steel beam for rush-repair were established by the finite element analysis software ANSYS and five different spans of beams were taken into consideration in the research of dynamic responses. DF4 locomotive hauling C70 freight heavy load marshalling trains model was established by dynamics software UM, in which specific wheel and rail relationship was used to found a combined simulation vibration system. After modeling, process of train running through the bridge was simulated to study several indexes including mid-span vertical deflection, mid-span lateral amplitude, derailment coefficient, rate of wheel load reduction and lateral force of wheel. These indexes made it possible to find out the changing pattern and the conclusion of maximum recommended speed.