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.
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 effectiveness of problem-based learning (PBL) on academic self-confidence and generic skills of graduate students in health-related fitness and wellness in Singapore
This study examined the effectiveness of Problem-based Learning (PBL) approach on enhancing graduate in-service physical education teachers' academic self-confidence, leadership and initiation. academic affect, and information processmg competence. A pre-test/post-test with quasi-experimental design was used. 27 graduate in-service physical education teachers from the National Institute of Education, Nanyang Technological University, Singapore, in a health-related and wellness module participated in this study. The intervention comprised teaching participants using a PBL approach for 12 teaching weeks. Measuring scales of high validity and reliability were developed for this study to measure participants' self-concept, leadership, academic affect and their information processing competence. Averaged post-test scores in most of generic skill aspects ( 8 out of II) were significantly higher than pre-test scores. Students had in general more positive attitudes toward the module and themselves at post- test than they had at pre-test. The results strongly support that teaching using a PBL approach is beneficial to both students' generic skill development and academic affect to teaching and learning.
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.
Effects of soy milk ingestion on anaerobic performance and physiological measures
The purpose of this study was to investigate the effects of soy protein supplementation to improve performance and recovery during repeated running anaerobic sprint test (RAST). Ten males (age: 23.2 ± 1.23 yrs) performed two RAST with a soy milk intervention (SOY; 500 mL soy milk + 4 g stevia sweetener) and a placebo control (CON; 500 mL water + 4 g stevia sweetener) over 7 days. The RAST consisted of six 35-m sprints with a 10-sec recovery between each sprint. The total effort time (sec) was not significant between SOY (32.77 ± 1.23) and CON (33.28 ± 1.71) (P = 0.179). Fatigue index in SOY (31.64 ± 5.20) was significantly lower than CON (37.30 ± 5.70) (P = 0.023). Mean power (Watts) (Soy: 499.27 ± 62.72, Con: 486.39 ± 86.13) (P = 0.410), relative power (Watts) (Soy: 9.34 ± 1.02, Con: 9.55 ± 1.51) (P = 0.461), peak blood lactate (mmol·L-1) (Soy: 9.75 ± 1.61, Con: 10.24 ± 1.90) (P = 0.488), and peak blood glucose (mmol·L-1) (Soy: 23.94 ± 3.90, Con: 25.09 ± 4.61) (P = 0.497) between trials were not significant. Peak blood lactate (r = -0.654) and glucose (r = -0.662) concentrations were inversely associated with mean power in the SOY trial. The results indicate that the soy milk intervention in RAST significantly lowered the fatigue index and, therefore, may be used to enhance sports performance involving anaerobic activities.
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.
Motion sensor outputs of children and adolescents walking and running to three treadmill speeds
The study examined the motion sensor outputs of Singaporean children and adolescents of both sexes to walking and running on a motorized treadmill (Quinton Series 90) under controlled laboratory conditions. 58 youths of normal body mass (N=58, age: 13.2±3.0 y; height: 1.53±0.02 m; body mass: 45.5±14.2 kg; BMI: 18.8± 3.0 kg/m2; Tanner rating: 2.5±1.3) were recruited for the study. Accelerometer (ActiGraph GT 1 M) activity (ActiCounts in counts/min) and step rate (ActiSteps in steps/min) and pedometer (Omron HJ 005-E) step rate (PedoSteps in steps/min), oxygen uptake (in ml/kg/min) and heart rate (in bpm) were obtained from 5-minutes stages of 0 % gradient of treadmill walking at 4 km/hr and running at 6 km/hr and 8 km/hr. Walking at 4 km/hr was estimated at 4.0-6.0 METs, whilst running at 6 km/hr and 8 km/hr was estimated at 6.3-8.6 and 10.0-11.4 METs, respectively. Motion sensor outputs increased significantly with treadmill speeds (76-101 % for ActiCounts; 22-24 % for ActiSteps and18-25 % for PedoSteps, all p<0.01) as did oxygen uptake (48-55 %) and heart rate (27-28 %) but there was no sex difference in activity or step rate or physiological responses (p>0.01). No meaningful relationships were obtained between accelerometer activity rate and oxygen uptake or heart rate. There was acceptable agreement between accelerometer and pedometer step rate for the walking and running on the treadmill but the difference between accelerometer and pedometer step rate was smallest at a treadmill running speed of 6 km/hr. These results show that accelerometer and pedometer step rates are useful and suitable measurements of physical activity involving walking and running among Singaporean children and adolescents of normal body mass. Further investigations are necessary to fully exploit the use of accelerometer data in physical activity research among young people.
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.