Arm-pull thrust in human swimming and the effect of post-activation potentiation
The aim of this study was to analyse the front-crawl arm-pull kinetics and kinematics, comparing it before and after post-activation potentiation (PAP), and the associations between variables describing of the arm-pull kinetics. Twelve male competitive swimmers were randomly assigned to perform two different warm-ups in a crossover manner: (i) non-PAP (control condition); and (ii) PAP (experimental condition). PAP consisted of 2 × 5 arm-pulls with resistance bands by both upper-limbs. Eight minutes later, participants underwent a 25 m all-out trial in front-crawl arm-pull. Kinetics (i.e., peak thrust, mean thrust and thrust-time integral) and kinematics (i.e., speed and speed fluctuation) were collected by an in-house customised system composed of differential pressure sensors, speedo-meter and underwater camera. There was a significant and large improvement of the arm-pull kinetics after completing the warm-up with PAP sets (0.010 < P < 0.054, 0.50 < d < 0.74). There were non-significant and small effects of PAP on speed (P = 0.307, d = 0.18) and speed fluctuation (P = 0.498, d = 0.04). Correlation coefficients among kinetic variables were significant with large associations (0.51 < R < 0.90, 0.001 < P < 0.088). In conclusion, warm-ups including PAP conditioning sets elicit a large improvement in the thrust, but with small improvement in performance. Variables used to characterise thrust are strongly correlated and hence can be used interchangeably.
Physiological differences between a noncontinuous and a continuous endurance training protocol in recreational runners and metabolic demand prediction
This study investigated the physiological difference in recreational runners between a non continuous and a continuous endurance training protocol. It also aimed to determine physiological surrogate that could monitor metabolic demand of prolonged running in real-time. For data collection, a total of 18 active male recreational runners were recruited. Physiological (HR, RR, RER, ṼO2, BLa), and overall perceptual (RPEO) responses were recorded against three designed test sessions. Session 1 included ṼO2submax test to determine critical speed (CS) at anaerobic threshold (AT). Session 2 was the non continuous CS test until exhaustion, having 4:1 min work-to-rest ratio at CS, whereas session 3 was the continuous CS test till exhaustion. As 1-min recovery during session 2 may change fatigue behavior, it was hypothesized that it will significantly change the physiological stress and hence endurance outcomes. Results reported average time to exhaustion (TTE) was 37.33(9.8) mins for session 2 and 23.28(9.87) mins for session 3. Participants experienced relatively higher metabolic demand (BLa) 6.78(1.43) mmol.l 1 in session 3 as compared to session 2 (5.52(0.93) mmol.l 1). RER was observed to increase in session 3 and decrease in session 2. Student’s paired t-test only reported a significant difference in TTE, ṼO2, RER, RPEO, and BLa at “End” between session 2 and 3. Reported difference in RPEO and %HRmax at “AT” were 5 (2.2) and 89.8 (2.60)% during session 2 and 6 (2.5) and 89.8 (2.59)% during session 3, respectively. Regression analysis reported strong correlation of %HRmax (adj.R-square = 0.588) with BLa than RPEO (adj. R-square = 0.541). The summary of findings suggests that decreasing RER increased TTE and reduced BLa toward “End” during session 2 which might have helped to have better endurance. The %HRmax was identified to be used as a better noninvasive surrogate of endurance intensity estimator.
The influence of mental training and playing circuit-based training program on student volleyball learning outcomes
This research was motivated by the need for more application of physical education learning models in the form of games, especially in volleyball learning. It is known that many students feel bored and unenthusiastic when taking volleyball lessons. Apart from that, students find it difficult and are not mentally prepared to carry out volleyball techniques; as a result, they feel anxious or afraid when doing these techniques in front of other friends. This experimental type of research aims to determine the effect of mental training and playing circuits-based training programs on the learning outcomes of elementary school volleyball students. This study included 44 fifth-grade students from 2 classes at Sekolah Dasar Pembangunan Laboratorium Universitas Negeri Padang. Purposive sampling technique was utilised. A pre- and post-test of volleyball skills were determined by volleyball experts. The paired t-test was used to analyze the data. Data analysis revealed that mental training-based training programs and playing circuits affected the learning outcomes of volleyball for elementary school students at Sekolah Dasar Pembangunan Laboratorium Universitas Negeri Padang. Results indicated significant differences between pre- and post-quality basic volleyball technical skills test (pre: highest score: 70; lowest score: 60; average score: 64.09 ± 2.81 vs. post: highest score: 77; lowest score: 65; average score: 68.68 ± 3.09; p = 0.000). The learning model based on mental training and playing sequences may improve basic volleyball technical skills and increase students' self-confidence and motivation when participating in learning.
Prediction of running performances for world class, elite, sub-elite, and collegiate athletes based on maximal aerobic speed and running Energy Reserve index
Prediction of performance is an important parameter in exercise, especially in sports. There are several ways to predict performance, however many are fraught with difficulties such as error of prediction being too large or the lack of reliability and validity [1]. The recently published Maximal Aerobic Speed (MAS) validation and the Running Energy Reserve Index (RERI) had lower errors in predicting world class, elite, sub elite and collegiate performances [1,2]. The use of MAS and Maximal Anaerobic Speed to predict performance has been used previously by Bundle et al [3]. However, the errors in acquiring MAS may have caused prediction errors due to the existence of large anaerobic energy. The concept of removing anaerobic energy from an individual to accurately acquire a true MAS is a novel idea to predict performances with lower errors in all sports, especially sports which involve running [1]. RERI is an index which may be useful for most practitioners. Using an example of a world class runner, Sebastian Coe’s 400m and 1609m in 1981, the prediction accuracy was 1.8% and 1.0% for his 800m and 1000m respectively. This was comparable to Bundle’s two trials equation (1000m = 1.5% and 800m = 2.0%). However, the Bundle’s equation is limited to only predicting performances up to 240 seconds. The results from the MAS and RERI studies suggest that RERI can accurately predict running performances of world class runners when utilizing any two running performances within 5000m distance performance. Kinesiologists can also use the RERI model as an accurate and non-invasive alternative to time consuming methods of determining anaerobic and aerobic running performances [4,5] across various modalities of sports [6]. Training can also be compartmentalized into aerobic and anaerobic energy systems with accuracy, thus optimizing and increasing the potential of individuals with customization specialized training. The concept of talent identification using RERI in terms of identifying superiority in one energy system versus another, may be used in streamlining the potential of an individual to his strengths. For example, RERI can be used to identify a striker in soccer who is superior in anaerobic energy system versus a midfielder who may need more aerobic energy system. Moreover, RERI can be used to select a short distance runner versus a long-distance runner. Such identification may help exercise practitioners to select and train accordingly with the energy systems. Hence, it is essential knowledge and information that Kinesiologists can use to develop training programs to suit athletes of various standards (youth, collegiate, sub-elite, elite, and world class) and predict training performance for them. Such specialized science-based training may improve and enhance overall sporting performances all over the world.
Effectiveness of modified perceived exertion scale on exercise intensity across age group, gender and exercise modalities
This study aims to conduct a systematic and meta-analysis to collate the current findings and assess the effectiveness of perceived exertion scales (original or modified), across various users profile (gender, age, exercise background) and exercise modalities (aerobic vs resistance).
Comparing the effects of plyometric and isometric strength training on dynamic and isometric force-time characteristics
The purpose of the study was to compare the change in dynamic and isometric force-time characteristics after plyometric (PLYO) or isometric strength training (ISO). Twenty-two endurance runners (age = 37 ± 6 years,stature = 1.71 ± 0.05 m, body mass = 62.7 ± 8.6 kg, weekly mileage = 47.3 ± 10.8 km) performed a countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) test during pre- and post-tests. They were then randomly assigned to either PLYO or ISO group and completed 12 sessions of intervention over six weeks. The PLYO included drop jump, single leg bounding and split jump, and the ISO included IMTP and isometric ankle plantar flexion. Significant and large time x group interactions were observed for CMJ countermovement depth (P = 0.037, ƞ²p = 0.21) and IMTP and relative peak force (PF) (P = 0.030, ƞ²p = 0.22). Significant and large main effects for time were observed in CMJ height, peak power, propulsive phase duration, countermovement depth, reactive strength index modified, IMTP PF and relative PF (P < 0.05, 0.20 ≤ ƞ²p ≤ 0.65). Effect for time showed small improvement in CMJ height for both PLYO (P < 0.001, d = 0.48) and ISO (P = 0.009, d = 0.47), small improvement in CMJ PP in PLYO (P = 0.020, d = 0.21), large increase in countermovement depth (P = 0.004, d = 1.02) and IMTP relative PF (P < 0.001, d = 0.87), and moderate increase in propulsive phase duration (P = 0.038, d = 0.65) and IMTP PF (P < 0.001, d = 0.55) in ISO. There were large differences between groups for percentage change in countermovement depth (P = 0.003, d = 0.96) and IMTP relative PF (P = 0.047, d = 0.90). In conclusion, both PLYO and ISO improved CMJ jump height via different mechanisms, while only ISO resulted in improved IMTP PF and relative PF.
Using Brain-Breaks® as a technology tool to increase attitude towards physical activity among students in Singapore
The purpose of this study was to investigate the effects of classroom-based Brain Breaks® Physical Activity Solution in Southeast Asia Singaporean primary school students and their attitude towards physical activity (PA) over a ten-week intervention. A total of 113 participants (8-11 years old) were randomly assigned to either an experimental (EG) or a control group (CG), with six classes to each group; the Brain Breaks® group (EG: six classes) and the Control group (CG: six classes). All EG members participated in a Brain Breaks® video intervention (three-five min) during academic classes and the CG continued their lessons as per normal. The student's attitudes towards PA in both research conditions were evaluated using the self-reported Attitudes toward Physical Activity Scale (APAS), applied before and after intervention. The effects of the intervention on APAS scores were analysed using a mixed model analysis of variance with Time as within-subject and Group as between-subject factors. The analysis revealed evidence in support of the positive effect of classroom video interventions such as Brain Breaks® on student's attitudes toward benefits, importance, learning, self-efficacy, fun, fitness, and trying to do their personal best in PA. The Brain Breaks® intervention provided a positive significant impact on students in Singapore. This study also revealed that interactive technology tools implemented into the school curriculum benefit students in terms of health and education.
Obesity prevention in Singapore: Collaborative efforts among government, health professionals and the community
Obesity has reached global epidemic proportions over the past 10 years. As countries become more affluent, their populations tend to adopt caloric balance problems that have plagued the USA and Western Europe. Obesity is classified as the second most serious reversible health problem, after smoking in the world today. The relationship between obesity and cardiovascular diseases is well documented. The increase in obesity in Asian countries is remarkable. In 2004, the prevalence of obesity in the adult population in Singapore increased upto 16% (high risk category: ≥ 27.5kg/m2) and prompted many forms of government action, encouraging collaboration between businesses, the educational system and non-governmental organizations. This paper reviews the rise of obesity in Singapore and some of the approaches being implemented to address this concern. Singapore, a multiethnic country, with Chinese, Indian and Malay populations, has to address diversity in customs, diet and religions to combat obesity. The collaborative efforts of various organizations such as the Ministry of Health (MOH), Ministry of Education (MOE) and the Health Promotion Board (HPB) have successfully improved the health status of Singaporeans. The fact that the rise in obesity in Singapore is lower than in other neighboring Asian countries attests to the partial success of the collaborative efforts.
Physical education & sports science expert book series
To design and write a book on chapters pertaining to a variety of sports for children and adolescents to enjoy the process of being physically active.
Background
The American College of Sports Medicine (ACSM, 2015) states that a sedentary lifestyle is one of the major risk factors for obesity and cardiovascular disease. Therefore, physical activity is essential and it starts from a young age. Children have to be exposed to a variety of sports, games and activities. ACSM recommends 60 minutes daily of physical activity for children and adolescents. If children are unable to accumulate 60 minutes in day, they can begin with a lower duration and subsequently increasing the duration slowly as they progress over the months. The following chapters are written and designed by our experts in their special area of work and sport that will provide a deeper understanding and greater insight to sports and exercise in general, from a recreational perspective to a competitive level. Each chapter will reveal the history, background, basic rules of the sport, and how to implement modified games during PE lessons. The chapters also provide PE educators, coaches and parents with necessary tools to teach the sport.
Body composition: Assessment, components, and hydration
In the modern era, health professional including scientists. health workers and researchers from different disciplines are focusing on body composition in the area of assessments. physiology. psychology. nutrition, etc. These valuable information garnered from research. and clinical practices is becoming an important factor in determining obesity such as formulation of an exercise programme and diet regiment. psychological profiles based on body image, nutritional status. functional capacity and risk for chronic diseases. Body composition is necessary for an individual to maintain proper work capacity, muscular strength. and the ability to perform daily tasks such as walking and lifting. Negative changes in body composition can lead to decline in physical performance capabilities of the individual. Currently there are number of indirect ways to assess body composition such as dual energy x-ray absorptiometry ( DEXA), under water weighing. body mass index (BMI), waist hip ratio ( WHR). bioelectric impedance ( BIA). skin fold measurement, circumference and girth measurements. These methods differ in accuracy and precision. Body composition is also affected by factors like hydration. This chapter focuses on the components of body composition and the various body composition techniques. In addition. it discusses the effects of hydration status on body composition.