Biomechanical modeling as a practical tool for predicting injury risk related to repetitive muscle lenthening during learning and training of human complex motor skills

Open access article. Creative Commons 4.0 International License (CC BY 4.0) appliesPrevious studies have shown that muscle repetitive stress injuries (RSIs) are often related to sport trainings among young participants. As such, understanding the mechanism of RSIs is essential for injury prevention. One potential means would be to identify muscles in risk by applying biomechanical modeling. By capturing 3D movements of four typical youth sports and building the biomechanical models, the current study has identified several risk factors related to the development of RSIs. The causal factors for RSIs are the muscle over-lengthening, the impactlike (speedy increase) eccentric tension in muscles, imbalance between agonists and antagonists, muscle loading frequency and muscle strength. In general, a large range of motion of joints would lead to over-lengthening of certain small muscles; Limb’s acceleration during power generation could cause imbalance between agonists and antagonists; a quick deceleration of limbs during follow-throughs would induce an impact-like eccentric tension to muscles; and even at low speed, frequent muscle over-lengthening would cause a micro-trauma accumulation which could result in RSIs in long term. Based on the results, the following measures can be applied to reduce the risk of RSIs during learning/training in youth participants: (1) stretching training of muscles at risk in order to increase lengthening ability; (2) dynamic warming-up for minimizing possible imbalance between agonists and antagonists; (3) limiting practice times of the frequency and duration of movements requiring strength and/or large range of motion to reducing micro-trauma accumulation; and (4) allowing enough repair time for recovery from micro-traumas induced by training (individual training time). Collectively, the results show that biomechanical modeling is a practical tool for predicting injury risk and provides an effective way to establish an optimization strategy to counteract the factors leading to muscle repetitive stress injuries during motor skill learning and training.Ye

The influence of X-factor (trunk rotation) and experience on the quality of the badminton forehand smash

Sherpa Romeo green journal. Open access article. Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License 9CC BY-NC-ND 3.0) appliesNo existing studies of badminton technique have used full-body biomechanical modeling based on three dimensional (3D) motion capture to quantify the kinematics of the sport. The purposes of the current study were to: 1) quantitatively describe kinematic characteristics of the forehand smash using a 15-segment, full-body biomechanical model, 2) examine and compare kinematic differences between novice and skilled players with a focus on trunk rotation (the X-factor), and 3) through this comparison, identify principal parameters that contributed to the quality of the skill. Together, these findings have the potential to assist coaches and players in the teaching and learning of the forehand smash. Twenty-four participants were divided into two groups (novice, n = 10 and skilled, n = 14). A 10-camera VICON MX40 motion capture system (200 frames/s) was used to quantify full-body kinematics, racket movement and the flight of the shuttlecock. Results confirmed that skilled players utilized more trunk rotation than novices. In two ways, trunk rotation (the X-factor) was shown to be vital for maximizing the release speed of the shuttlecock – an important measure of the quality of the forehand smash. First, more trunk rotation invoked greater lengthening in the pectoralis major (PM) during the preparation phase of the stroke which helped generate an explosive muscle contraction. Second, larger range of motion (ROM) induced by trunk rotation facilitated a whip-like (proximal to distal) control sequence among the body segments responsible for increasing racket speed. These results suggest that training intended to increase the efficacy of this skill needs to focus on how the X-factor is incorporated into the kinematic chain of the arm and the racket.Ye

Differential Metabolites and Metabolic Pathways Involved in Aerobic Exercise Improvement of Chronic Fatigue Symptoms in Adolescents Based on Gas Chromatography–Mass Spectrometry

Studies have found that the prevalence of chronic fatigue syndrome (CFS) in adolescents has continued to increase over the years, affecting learning and physical health. High school is a critical stage for adolescents to grow and mature. There are inadequate detection and rehabilitation methods for CFS due to an insufficient understanding of the physiological mechanisms of CFS. The purpose of this study was to evaluate the effect and metabolic mechanisms of an aerobic running intervention program for high school students with CFS. Forty-six male high school students with CFS were randomly assigned to the exercise intervention group (EI) and control group (CFS). Twenty-four age- and sex-matched healthy male students were recruited as healthy controls (HCs). The EI group received the aerobic intervention for 12 weeks, three times a week, in 45-min sessions; the CFS group maintained their daily routines as normal. The outcome measures included fatigue symptoms and oxidation levels. Keratin was extracted from the nails of all participants, and the oxidation level was assessed by measuring the content of 3-Nitrotyrosine (3-NT) in the keratin by ultraviolet spectrophotometry. All participants’ morning urine was collected to analyze urinary differential metabolites by the GC-MS technique before and after the intervention, and MetaboAnalyst 5.0 was used for pathway analysis. Compared with before the intervention, the fatigue score and 3-NT level in the EI group were significantly decreased after the intervention. The CFS group was screened for 20 differential metabolites involving the disruption of six metabolic pathways, including arginine biosynthesis, glycerolipid metabolism, pentose phosphate pathway, purine metabolism, β-alanine metabolism, and arginine and proline metabolism. After the intervention, 21 differential metabolites were screened, involved in alterations in three metabolic pathways: beta-alanine metabolism, pentose phosphate metabolism, and arginine and proline metabolism. Aerobic exercise was found to lessen fatigue symptoms and oxidative levels in students with CFS, which may be related to the regulation of putrescine (arginine and proline metabolism), 6-Phospho-D-Gluconate (starch and sucrose metabolism pathway), and Pentose (phosphate metabolism pathway)

Wearables, Biomechanical Feedback, and Human Motor-Skills’ Learning & Optimization

Biomechanical feedback is a relevant key to improving sports and arts performance. Yet, the bibliometric keyword analysis on Web of Science publications reveals that, when comparing to other biofeedback applications, the real-time biomechanical feedback application lags far behind in sports and arts practice. While real-time physiological and biochemical biofeedback have seen routine applications, the use of real-time biomechanical feedback in motor learning and training is still rare. On that account, the paper aims to extract the specific research areas, such as three-dimensional (3D) motion capture, anthropometry, biomechanical modeling, sensing technology, and artificial intelligent (AI)/deep learning, which could contribute to the development of the real-time biomechanical feedback system. The review summarizes the past and current state of biomechanical feedback studies in sports and arts performance; and, by integrating the results of the studies with the contemporary wearable technology, proposes a two-chain body model monitoring using six IMUs (inertial measurement unit) with deep learning technology. The framework can serve as a basis for a breakthrough in the development. The review indicates that the vital step in the development is to establish a massive data, which could be obtained by using the synchronized measurement of 3D motion capture and IMUs, and that should cover diverse sports and arts skills. As such, wearables powered by deep learning models trained by the massive and diverse datasets can supply a feasible, reliable, and practical biomechanical feedback for athletic and artistic training

Effects of the Policy of Physical Education Entrance Examination for Senior High School on Health in Middle School Students

Background: The policy of the Physical Education (PE) Entrance Examination for Senior High School (PEESHS) is an operable and measurable educational policy proposed by the Chinese government to solve the youth’s physical health problems and promote health in middle school students. In recent years, the reform of PEESHS policy has brought youth sports to a new climax, and determining how to achieve the maximum benefit of health promotion with the PEESHS policy is the current focus of the Chinese government, society, schools, and families. The primary purpose was to investigate the health promotion benefits of PE on junior high school students under PEESHS policy and clarify the differences and correlation of overall health, physical fitness, sports participation, social adaptation, and learning facilitation. The secondary aim was to assess the practical value of PEESHS policy implementation on health promotion. Methods: The questionnaire of this study was compiled in four steps, and 31 provincial capitals across China were selected as sampling areas, using the convenience sampling method and snowball sampling method, respectively. The number of questionnaires collected was 11,373 (5703 online; 5670 offline), of which 8574 were valid, with an efficiency rate of 75.4%. Ultimately, 8574 students (4199 girls; 4375 boys) were recruited from junior high schools in 31 provinces and municipalities. Data analyses were performed using ANOVA, t-test, and Pearson bivariate correlation. Results: The results showed that the PEESHS significantly improved participants’ physical fitness, interpersonal relationships, exercise participation, learning efficiency, and psychological health after preparing for PEESHS. Exercise participation and physical fitness showed the most significant positive correlation. Excessive sports intensity was detrimental to health promotion. Conclusion: The PEESHS policy has significantly impacted the health of students participating in PEESHS

Obtaining Vital Distances Using Wearable Inertial Measurement Unit for Real-Time, Biomechanical Feedback Training in Hammer-Throw

The hammer throw is one of the regular track and field competitions, but unlike other events, it has not seen a new world record for over three decades. The standstill may be caused by the lack of scientifically based training. In our previous work, we have developed a wireless/wearable device for the wire tension measurement in order to develop real-time biomechanical feedback training. In this paper, we show the improvement of our wearable system by adding two sensors for tracking of two vital vertical distances. The paper describes the details related to the development of turning an inertial measurement unit into a tracking device for the dynamic distances. Our preliminary data has shown that the dynamic data of the hip and wrist could be used for revealing the coordination between the upper and the lower limbs during a throw. In conjunction with wearable wire-tension measurement, various motor control patterns employed for hammer throwing could be demystified. Such real-time information could be valuable for hammer-throw learning and optimization. Further studies are required to verify the potentials of the wearable system for its efficiency and effectiveness in coaching practice

Dopamine Detection Based on Low-Voltage Oxide Homojunction Electric-Double-Layer Thin-Film Transistors

Quick and accurate detection of dopamine (DA) is of great significance for routine analysis and biomedical diagnosis. Here, low-voltage indium-zinc-oxide (IZO) homojunction electric-double-layer (EDL) transistors using nanogranular SiO2 electrolytes as the gate dielectrics are proposed for DA detection. A DA detection limit of 0.1 nM with good selectivity is obtained at a low voltage of 0.8 V. The DA sensing mechanism can be attributed to the modulation of surface potential of the indium-tin-oxide (ITO) gate electrode by preferential binding of DA molecule to phenylboronic acid. Such low-voltage oxide-based EDL transistors have potential application in biochemical sensors

Relationships between Risk Events, Personality Traits, and Risk Perception of Adolescent Athletes in Sports Training

Personality traits have close relationships with risky behaviors in various domains, including physical education, competition, and athletic training. It is yet little known about how trait personality dimensions associate with risk events and how vital factors, such as risk perception, could affect the happening of risk events in adolescent athletes. The primary purpose of this study is to investigate the prediction of risk events by regression analysis with dimensions of personality, risk perception and sports, relations between risk events, risk perception, and the facets of the personality dimensions via data collecting from 664 adolescent athletes aged 13–18 years (male 364, female 300). Secondary intent is to assess school-specific levels of training risks among sports schools, regular schools, and sports and education integrated schools. The results show that psychology events are the strongest predicted by personality traits, risk perception, and sports, followed by injury and nutrition. Emotionality has the most significant positive correlation with risk events, while other traits have a significant negative correlation with risk events, except agreeableness. The integration schools are more conducive to the healthy development of adolescent athletes’ personalities. Moreover, the research indicates that sports training can strengthen the development directions of different personality characteristics