Maximum oxygen uptake and body composition of healthy Hong Kong Chinese adult men and women aged 20 – 64 years

Abstract

The aims of the present study were to assess the maximal oxygen uptake and body composition of adult Chinese men and women, and to determine how these variables relate to age. The cross-sectional sample consisted of 196 men and 221 women aged 20 – 64 years. Maximal oxygen uptake ([Vdot]O_2max) was determined by indirect calorimetry during a maximal exercise test on an electrically braked cycle ergometer. The correlations between [Vdot]O_2max and fat mass were ?0.52 in men and ?0.58 in women. Linear regression defined the cross-sectional age-related decline in [Vdot]O_2max as 0.35 ml · kg^?1 · min^?1 · year^?1 in men and 0.30 ml · kg^?1 · min^?1 · year^?1 in women. Multiple regression analysis showed that more than 50% of this cross-sectional decline in [Vdot]O_2max was due to fat mass, lean mass, and age. Adding fat mass and lean mass to the multiple regression models reduced the age regression mass from 0.35 to 0.24 ml · kg^?1 · min^?1 · year^?1 in men and from 0.30 to 0.15 ml · kg^?1 · min^?1 · year^?1 in women. We conclude that age, fat mass, and lean mass are independent determinants of maximal oxygen uptake in Chinese adults.     

Effects of agonist–antagonist complex resistance training on upper body strength and power development

Abstract

The objective of this study was to examine the chronic effects on strength and power of performing complex versus traditional set training over eight weeks. Fifteen trained males were assessed for throw height, peak velocity, and peak power in the bench press throw and one-repetition maximum (1-RM) in the bench press and bench pull exercises, before and after the eight-week programme. The traditional set group performed the pulling before the pushing exercise sets, whereas the complex set group alternated pulling and pushing sets. The complex set training sessions were completed in approximately half the time. Electromyographic (EMG) activity was monitored during both test sessions in an attempt to determine if it was affected as a result of the training programme. Although there were no differences in the dependent variables between the two conditions, bench pull and bench press 1-RM increased significantly under the complex set condition and peak power increased significantly under the traditional set condition. Effect size statistics suggested that the complex set was more time-efficient than the traditional set condition with respect to development of 1-RM bench pull and bench press, peak velocity and peak power. The EMG activity was not affected. Complex set training would appear to be an effective method of exercise with respect to efficiency and strength development.     

Height,mass and skeletal maturity of elite Portuguese soccer players aged 11–16 years

Height, mass and skeletal maturity (Fels method) were assessed in 135 elite youth soccer players aged 10.7-16.5 years (only two boys were ?11.0 years). Sample sizes, years of training and current weekly training volume by two-year age groups were: 11-12 years ( n = 63), 2.6 - 1.0 years and 4.1 - 1.7 h; 13-14 years ( n = 29), 3.1 - 1.6 years and 4.5 - 1.7 h; 15-16 years ( n = 43), 4.7 - 2.4 years and 6.1 - 2.0 h. The oldest age group included membersof the national youth team.Heights and masses were compared to US reference values,and skeletal age and chronological age were contrasted. The players were also classified as late, average ('on time') and early maturers on the basis of differences between skeletal and chronological age, with the average category including boys with skeletal ages within - 1 year of chronological age. The mean heights and masses of 11- to 12-year-old soccer players equalled the US reference values, while those of players aged 13-14 and 15-16 years were slightly above the reference values. The mean skeletal age approximated mean chronological age in players aged 11-12 years (12.4 - 1.3 and 12.3 - 0.5 years, respectively), while mean skeletal age was in advance of mean chronological age in the two older groups (14.3 - 1.2 and 13.6 - 0.7 years, respectively, in 13- to 14-year-olds; 16.7 - 1.0 and 15.8 - 0.4 years, respectively, in 15- to 16-year-olds). Seven boys in the oldest age group were already skeletally mature and were not included when calculating differences between skeletal and chronological age. The proportion of late maturing boys in this sample of elite soccer players decreased with increasing chronological age. Among 11- to 12-year-old players, the percentages of late and early maturing boys were equal at 21% ( n = 13). Among 13- to 14-year-old players, the percentages of late and early maturing boys were 7% ( n = 2) and 38% ( n = 11) respectively, while among players aged 15-16 years the percentages of late and early maturing boys were 2% ( n = 1) and 65% ( n = 28) respectively. The results of this comparative analysis suggest that the sport of soccer systematically excludes late maturing boys and favours average and early maturing boys as chronological age and sport specialization increase. It is also possible that late maturing boys selectively drop-out of soccer as age and sport specialization increase.     

Effects of rule changes on physical demands and shot characteristics of elite-standard men’s squash and implications for training

The physical demands and rally characteristics of elite-standard men’s squash have not been well documented since recent rule changes (scoring and tin height). This information is needed to design optimal training drills for physical conditioning provided here based on an analysis of movement and shot information. Matches at the 2010 (n = 14) and 2011 (n = 27) Rowe British Grand Prix were analysed. Rallies were split into four ball-in-play duration categories using the 25th (short), 75th (medium), 95th percentiles (long) and maximum values. Cohen’s d and chi-squared tests of independence evaluated effects of rally and rule changes on patterns of play. The proportion of long, middle and short shots was related to the duration of the rally with more shots played in the middle and front of the court in short rallies (phi = 0.12). The frequencies of shots played from different areas of the court have not changed after the adoption of new rules but there is less time available to return shots that reflect the attacking nature of match play for elite-standard men players. Aspiring and current elite-standard players need to condition themselves to improve their ability to cope with these demands using the ghosting patterns presented that mimic demands of modern match play.     

Effects of stress inoculation training on self‐report,behavioural and psychophysiological reactions to abseiling

The study examined the effect of stress inoculation training on the level of self‐reported stress and anxiety, overt signs of distress and the physiological impact of the stress of abseiling. Twenty volunteer subjects were randomly assigned to either a ‘no training’ control group or a stress inoculation training group, following which both groups of subjects had to complete a test abseil from the roof of a 21.2 m building. Prior to descent, two self‐report measures were taken: an intensity score derived from the word or phrase chosen by subjects from the Perceived Stress Index to best describe their feelings and a state anxiety score from Spielberger's State Trait Anxiety Inventory. Overt distress was also evaluated by a ‘blind’ observer also using the Perceived Stress Index. In addition, heart rate was monitored just prior to and throughout the abseil using a telemetry system. The stress inoculation group showed significantly less self‐reported anxiety and stress and less behavioural signs of distress as judged by the observer. However, there were no significant differences between the groups in terms of heart rate. In addition, while self‐report and the assessment of the observer were highly inter‐correlated, these measures were poorly correlated with heart rate.     

Effects of a physical education-based coping training on adolescents’ coping skills,stress perceptions and quality of sleep

Background: Although most adolescents successfully manage the transition between childhood and adulthood, the speed and magnitude of these changes may exceed the coping abilities of a significant number of young people. For vocational students, additional responsibilities arise during the vocational school transition and the need to balance academic and job-related requirements. An expanding body of literature suggests that adolescence is a vulnerable period for the development of psychiatric diseases and as such, the need to develop an adequate coping repertoire is receiving increasing attention globally. The growing awareness of long-term consequences of stress has led governments to instill school-based resilience promotion programs. For instance, the new physical education (PE) curriculum of vocational (vocational education and training (VET)) students in Switzerland addresses stress management, because stress-related diseases at the workplace have become commonplace among young professionals.

Purpose: Our aim was to develop, implement and evaluate a PE-based coping training (EPHECT) for VET students. Therefore, we adapted components of extant field-tested coping training programs and tailored them to the unique needs of VET students. To facilitate the standardization of the program, each teacher received a teaching manual. Moreover, drawing upon experiential learning theory, we introduced the contents of the coping training in PE class through practical, movement-based exercises in PE. Students also received a workbook for use at home.

Participants and research design: In this cluster randomized controlled trial, eight classes from a Swiss vocational school participated (N?=?131, M_age?=?16.22?±?1.12, 35% females). Two trained PE teachers implemented the program with students in the intervention group (IG?=?67) for three months, while students in the other four classes maintained regular PE (CG?=?64) to comprise the control group. To evaluate the coping training, all participants completed several self-report psychological questionnaires (assessing stress, coping and sleep) at baseline and follow-up. IG students completed further questions with regard to intervention fidelity at follow-up.

Data analysis: To evaluate possible effects of the coping training on stress, coping and sleep, a 2?×?2 repeated-measures analysis of variance design was executed with time (pre vs. post) and group (IG vs. CG) as within- and between-subject factors.

Findings: Over time, IG students significantly increased their adaptive coping compared to CG students, while stress and sleep remained relatively stable for both. Regularly completing one’s homework reinforced this effect because it was significantly associated with students’ reflection and compliance.

Conclusion: A complete and accurate implementation of a PE-based coping training can make a positive contribution to the development of adaptive coping skills among adolescents attending vocational schools. This PE-based program allows students to experience their responses to stress directly and offers opportunities to experiment with different coping strategies. Adaptive coping skills are vital for successful stress management and the prevention of stress-related disorders across the work domain and in everyday life.     

Time–motion,heart rate,perceptual and motor behaviour demands in small-sides soccer games: Effects of pitch size

Abstract

The aim of this study was to examine physical, physiological, and motor responses and perceived exertion during different soccer drills. In small-sided games, the individual playing area (～275 m², ～175 m², and ～75 m²) was varied while the number of players per team was kept constant: 5 vs. 5 plus goalkeepers. Participants were ten male youth soccer players. Each session comprised three small-sided game formats, which lasted 8 min each with a 5-min passive rest period between them. A range of variables was recorded and analysed for the three drills performed over three training sessions: (a) physiological, measured using Polar Team devices; (b) physical, using GPS SPI elite devices; (c) perceived exertion, rated using the CR-10 scale; and (d) motor response, evaluated using an observational tool that was specially designed for this study. Significant differences were observed for most of the variables studied. When the individual playing area was larger, the effective playing time, the physical (total distance covered; distances covered in low-intensity running, medium-intensity running, and high-intensity running; distance covered per minute; maximum speed; work-to-rest ratio; sprint frequency) and physiological workload (percent maximum heart rate; percent mean heart rate; time spent above 90% maximum heart rate), and the rating of perceived exertion were all higher, while certain motor behaviours were observed less frequently (interception, control and dribble, control and shoot, clearance, and putting the ball in play). The results show that the size of the pitch should be taken into account when planning training drills, as it influences the intensity of the task and the motor response of players.     

A comparison of the agreement,internal consistency,and 2-day test stability of the InBody 720, GE iDXA,and BOD POD® gold standard for assessing body composition

The study compared the agreement, internal consistency, and measurement stability of the GE iDXA, BOD POD, and InBody 720. Body composition of 43 men and 37 women (31.4 ± 10.7 years; 90% Caucasian and 10% other) was assessed in triplicate using each method over two different days. Mean percent body fat (% BF) of the participants was different for all three machines (27.6 ± 10.0% [GE iDXA)] 25.6 ± 10.4% [BOD POD], and 21.3 ± 10.6% [InBody 720]; p < .05). The coefficient of variation for same day repeated measures was 1.06% (GE iDXA), 3.29% (BOD POD), and 2.97% (InBody 720). The coefficient of variation for 2-day repeated measures was 1.81% (GE iDXA), 4.61% (BOD POD), and 4.24% (InBody 720). The difference between the GE iDXA and BOD POD was within acceptable variability, while the InBody 720 significantly underestimated % BF. The internal consistency was highest for the GE iDXA, followed by the InBody 720, and then the BOD POD.     

The acute effects of resistance exercise on affect,anxiety, and mood – practical implications for designing resistance training programs

ABSTRACT

Research in aerobic exercise has linked the affective responses (pleasure–displeasure) experienced during exercise to future exercise participation. While this is yet to be confirmed in anaerobic activities, it can be inferred that making resistance exercise (RE) more psychologically rewarding is an important consideration. The purpose of this article is to review the acute effects of RE on affect, anxiety, and mood and to draw conclusions on how to maximize feelings of pleasure in an effort to increase rates of participation. This review provides evidence to support lower training volumes performed at low to moderate intensities (50–70% 1RM) with long inter-set rest intervals (90–150 s). Additional recommendations are provided based on physiological and theoretical support, but there is a strong need for more research on the affective experience of RE.     

The effect of playing status,maturity status,and playing position on the development of match skills in elite youth football players aged 11–18 years: A mixed-longitudinal study

This mixed-longitudinal study examined the development of match skills in elite male youth footballers (aged 11–18 years), while considering the effect of playing status, maturity status, and playing position. Across two seasons, 126 elite male youth footballers were assessed in 1–10 competitive matches (401 player-matches). For each match, the on-the-ball actions of each player were recorded using a notation system. The match skills observed were frequencies of successful passes, on-target shots, dribbles, crosses, clearances, and tackles/blocks/interceptions. Multilevel Poisson analysis was used to model the development of players, with regard to each match skill. Modelling revealed significant (p?p?p?p?p?相似文献