An exercise protocol that simulates the activity patterns of elite junior squash

Squash is a popular racket sport that requires intermittent activity with frequent bursts of near maximal-intensity exercise. Consequently, effective physiological and thermoregulatory responses are important contributors to performance during squash match-play. Controlled field-based simulation protocols have been introduced in a growing number of sports, which allow sports scientists to investigate changes in physiology and the efficacy of various interventions in sport-specific contexts. This study aimed to develop an exercise protocol that simulates the physiological requirements of elite squash match-play. Eight elite junior squash players (age 16.2+/-0.8 years, height 1.76+/-0.06 m, body mass 61.3+/-5.9 kg; mean+/-s) completed the following in a randomized order: (1) a squash match against a player of similar standard and (2) a squash-specific incremental exercise protocol (multistage squash test [MST]) followed by the squash simulation protocol (SSP). The multistage squash test was continued for 18.0+/-1.0 min and elicited near maximal post-MST heart rates, blood lactate concentrations and ratings of perceived exertion (198+/-9 beats.min-1, 5.7+/-1.7 mmol.l-1 and 18+/-1, respectively). The SSP was 12.2 min in length compared with mean game length during competitive matches of 10.0+/-1.6 min (P=0.27). Peak heart rates were similar during the SSP and match-play (192+/-11 and 189+/-6 beats.min-1, respectively; P=0.44). Mean exercising heart rates were similar during the SSP (180+/-8 beats.min-1) and match-play (179+/-13 beats.min-1; P=0.73). Peak blood lactate concentrations during the SSP and match-play were 3.5+/-1.5 and 2.4+/-1.2 mmol.l-1 (P=0.07), respectively. Peak ratings of perceived exertion during the SSP and match-play were similar (17+/-2 and 17+/-2, respectively; P=0.64). It was concluded that the SSP closely replicated the demands of squash match-play in elite junior squash players. Furthermore, the SSP provides coaches and scientific support staff with a controlled squash-specific exercise protocol that has potential application in the objective investigation of a range of interventions such as training programmes, nutritional supplements and strategies to maintain core body temperature.     

Effect of skill decomposition on racket and ball kinematics of the elite junior tennis serve

Whole body kinematics of the tennis serve have been reported extensively in the literature, yet comparatively less information exists regarding the kinematic characteristics of the swing and toss. In attempting to develop consistency in placement of the toss and racket trajectory, coaches will often decompose the serve and practice it in separate parts. A 22-camera VICON MX motion analysis system, operating at 250 Hz, captured racket, ball and hand kinematics of the serves of five elite junior players under three conditions. The conditions were flat first serves (FS) directed to a 1 × 1 m target bordering the ‘T’ of the deuce service box, a ball toss (BT) in isolation and a free swing (SW) in isolation. Players were instructed to perform BT and SW as in the FS. Paired t-tests assessed within-group differences in hand, racket and ball kinematics between the discrete skill and the two decomposed conditions. Vertical displacement of the ball at its zenith increased significantly during BT compared with the FS and temporal associations between racket and ball motion during the FS (r = 0.861) were affected during task decomposition. This study questions the pervasive use of task decomposition in the development of the tennis serve.     

Self-reported tolerance of the intensity of exercise influences affective responses to and intentions to engage with high-intensity interval exercise

This study investigated the effect of self-reported tolerance of the intensity of exercise on affective responses to, self-efficacy for and intention to repeat low-volume high-intensity interval exercise (HIIE). Thirty-six healthy participants (mean age 21 ± 2 years) were split into high tolerance (HT; n = 19), low tolerance (LT; n = 9), and very low tolerance (VLT; n = 8) of exercise intensity groups. Participants completed 10 × 6 s cycle sprints with 60 s recovery. Affective valence and perceived activation were measured before exercise, after sprints 2, 4, 6, 8, 10, and 20 min post-HIIE. Intention and self-efficacy were assessed 20 min post-HIIE. Affective valence was significantly lower in VLT vs. LT (P = 0.034, d = 1.01–1.14) and HT (P = 0.018, d = 1.34–1.70). Circumplex profiles showed a negative affective state in VLT only. The VLT group had lower intentions to repeat HIIE once and three times per week than HT (P < 0.001, d = 1.87 and 1.81, respectively) and LT (P = 0.107, d = 0.85; P = 0.295, d = 0.53, respectively). Self-efficacy was not influenced by tolerance. Self-reported tolerance of exercise intensity influences affective responses to and intentions to engage with HIIE.     

Examining the sources of self-efficacy for physical activity within the sport and exercise domains

Self-efficacy theory is the most prominent sub-theory stemming from Bandura's social cognitive theory (1986). The theory posits that people will be more likely to engage in behaviors they believe they can successfully perform and avoid behaviors in which they feel they will be unsuccessful. Self-efficacy perceptions help to shape individuals’ efforts, affective experiences, and enjoyment of physical activities, particularly at higher intensities. The purpose of this literature review is to synthesize the current literature on self-efficacy for physical activity within the sport and exercise domains, focusing on the mechanisms through which self-efficacy perceptions are derived and concluding with a summary of positive and negative aspects of the literature and suggestions for avenues of further investigation.     

The ingestion of a caffeinated energy drink improves jump performance and activity patterns in elite badminton players

The aim of this study was to investigate the effectiveness of a caffeine-containing energy drink to enhance physical and match performance in elite badminton players. Sixteen male and elite badminton players (25.4 ± 7.3 year; 71.8 ± 7.9 kg) participated in a double-blind, placebo-controlled and randomised experiment. On two different sessions, badminton players ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed the following tests: handgrip maximal force production, smash jump without and with shuttlecock, squat jump, countermovement jump and the agility T-test. Later, a 45-min simulated badminton match was played. Players’ number of impacts and heart rate was measured during the match. The ingestion of the caffeinated energy drink increased squat jump height (34.5 ± 4.7 vs. 36.4 ± 4.3 cm; P < 0.05), squat jump peak power (P < 0.05), countermovement jump height (37.7 ± 4.5 vs. 39.5 ± 5.1 cm; P < 0.05) and countermovement jump peak power (P < 0.05). In addition, an increased number of total impacts was found during the badminton match (7395 ± 1594 vs. 7707 ± 2033 impacts; P < 0.05). In conclusion, the results show that the use of caffeine-containing energy drink may be an effective nutritional aid to increase jump performance and activity patterns during game in elite badminton players.     

The Loughborough Intermittent Shuttle Test: A field test that simulates the activity pattern of soccer

The aims of this study were to describe and determine the test-retest reliability of an exercise protocol, the Loughborough Intermittent Shuttle Test (the LIST), which was designed to simulate the activity pattern characteristic of the game of soccer. The protocol consisted of two parts: Part A comprised a fixed period of variable-intensity shuttle running over 20 m; Part B consisted of continuous running, alternating every 20 m between 55% and 95% VO 2max , until volitional fatigue. Seven trained games players (age 21.5 +/- 0.9 years, height 182 +/- 2 cm, body mass 80.1 +/- 3.6 kg, VO 2max 59.0 +/- 1.9 ml kg -1 min -1 ; mean s x ) performed the test on two occasions (Trial 1 and Trial 2), at least7 days apart, to determine the test-retest reliability of the sprint times and running capacity. The physiological and metabolic responses on both occasions were also monitored. The participants ingested water ad libitum during the first trial, and were then prescribed the same amount of water during the second trial. The 15 m sprint times during Trials 1 and 2 averaged 2.42 +/- 0.04 s and 2.43 +/- 0.04 s, respectively. Run time during Part B was 6.3 +/- 2.0 min for Trial 1 and 6.1 +/- 1.3 min for Trial 2. The 95% limits of agreement for sprint times and run times during Part B were -0.14 to 0.12 s and -3.19 to 2.16 min respectively. There were no differences between trials for heart rate, rating of perceived exertion, body mass change during exercise, or blood lactate and glucose concentrations during the test. Thus, we conclude that the sprint times and the Part B run times were reproducible within the limits previously stated. In addition, the activity pattern and the physiological and metabolic responses closely simulated the match demands of soccer.     

Using the interaction of speed and acceleration to detect repeated-sprint activity in team sports

ABSTRACT

Purpose

To compare the occurrence and characteristics of repeated-sprint (RS) activity in elite team sport competition when classified according to speed and/or acceleration, and their interaction via metabolic power (P_met). Methods: Elite male hockey players (N = 16) wore player-tracking devices in six international matches. Sprint efforts were defined using four separate classifications: speed >5.5 m?s^?1, acceleration >1.5 m?s^?2, speed-or-acceleration, and P_met >25.5 W?kg^?1. RS bouts were defined as ≥3 efforts with mean recovery ≤21 s. For P_met, RS bouts were also classified using a maximal recovery period ≤21 s. The number of sprint efforts and RS bouts, and the number of efforts, effort durations and recovery periods within RS bouts, were compared across each classification method, and between mean and maximal recovery criteria. Results: More RS bouts were identified via P_met (8.5 ± 2.8) than either speed and/or acceleration, and comprised more efforts (4.0 ± 0.4) with shorter recovery periods (11.5 ± 1.8 s). Fewer RS bouts (7.3 ± 2.8 vs. 8.5 ± 2.8) were identified with a maximum rather than mean recovery criterion. Conclusions: Definitions of sprint efforts and recovery periods which reflect ATP depletion and replenishment via P_met suggest that RS activity occurs frequently in team sport competition, and is more demanding than when speed and/or acceleration are used to define RS activity in variable-speed locomotion.     

湖北省新农村建设中农民参与体育活动的意愿与态度调查

摘要：采用问卷调查、实地访谈等研究方法,从性别、婚姻状况、年龄结构、经济收入、文化程度、职业身份等6个人口学变量考察了湖北省农民参与体育活动的意愿与态度。结果表明：湖北省农民参与体育活动的主体意识日益增强;农民对发展新农村体育的意愿主要受文化程度、家庭年收入、婚姻状况3个因素的影响,其中文化程度对其影响最大;从农民参与体育活动的意愿与态度来看,男性较女性强,未婚者强于已婚者,离婚或丧偶者最弱,在年龄结构上彰显出“中间小、两头大”的特征,文化程度和家庭年收入状况与之正相关,职业身份则与其存在一定的相关性。提出了加大“农民体育健身工程”的宣传力度、注重培养“消极群体”的积极的体育活动意愿与态度等建议。     

An Examination of Sport Participation Tracking and Adult Physical Activity for Participants of the Michigan State University Motor Performance Study

ABSTRACT

Research tracking sport participation from youth to adulthood is relatively rare, as is research that tracks youth sport participation with regard to adult physical activity (PA) levels, especially in the United States. Aims of this study were: 1) To investigate the degree to which sport participation tracked across youth, adolescence, and early adulthood in a sample of participants from the Michigan State University Motor Performance Study (MPS), and 2) Determine if differences existed in their levels of adult PA relative to prior sport participation. In total, 256 (60.8%) former participants from the MPS completed follow-up surveys regarding routine sport participation and PA across the previous year. Sport participation tracked consistently from youth to college. Further, regardless of the level of youth sport participation, adult leisure time PA was relatively consistent among groups. Although the study did not directly test the influence of the MPS on subsequent adult outcomes, our findings suggest that participants’ past sport participation was not a good predictor of adult PA for those who were involved in a program that emphasized fundamental motor skills in youth. Further investigation of such programs can help to better inform their influence on adult PA.     

身体活动提高青少年自尊水平机制的分析

在近年来国内外该领域研究的基础上，试分析身体活动提高青少年自尊水平的机制。     

Sport facility proximity and physical activity: Results from the Study of Community Sports in China

Abstract

Increased sport facility proximity is associated with higher likelihood of meeting physical activity (PA) recommendations in western studies, but it is uncertain whether the findings can be generalized to the Chinese population. From September 2012 to December 2012, 3926 participants drawn from China using a multi-stage sampling strategy were invited to participate in the Study of Community Sports in China. Participants' demographics, commuting time to the nearest sport facility and PA levels were assessed. Among 3926 participants included (51.2% female) in the final analysis, 878 (22.4%) of them met the PA recommendation. Participants who spent ≥30 minutes in commuting time had 80% odds [odds ratio (OR): 0.80 (95% CI: 0.65–0.98)] of meeting the PA recommendation compared to those who spent less than 10 minutes. For every 10-minute increment in commuting time, the odds reduced by 6% [OR = 0.94 (0.88–0.99)]. The observed associations were not appreciably modified by age, gender or education level. In this cross-sectional community-based study, we found that residents in China were less likely to meet the PA recommendation if they needed more commuting time to the nearest sport facility. Increasing sport facility proximity may be effective in improving the PA levels in the Chinese population.     

The validity of the commercially-available,low-cost,wrist-worn Movband accelerometer during treadmill exercise and free-living physical activity

Low-cost physical activity monitors may provide a more accurate measure of physical activity than subjective methods (e.g., self-report) while being less costly than research-grade accelerometers. The present study assessed the validity of a low-cost monitor (Movband 2) to estimate physical activity behavior/intensity. Participants (N = 23, n = 16 female, BMI = 22.9 ± 4.0 kg/m², age = 21.9 ± 1.6 years) completed four, five-minute treadmill stages (2.0, 3.0, 4.0, 5.0 MPH) while wearing both the Movband and the previously-validated Actigraph monitor. Oxygen consumption (VO₂) was recorded during each stage (Laboratory assessment). A subset (n = 15, n = 10 female, BMI = 22.2 ± 3.2 kg/m², age = 21.5 ± 0.8 years) of these participants then wore the two accelerometers for three days (Free-living assessment). During the Laboratory assessment there were strong, significant (r = 0.94, p ≤ 0.001) relationships between Movband and Actigraph counts and VO₂. During Free-living assessment there was also a strong, significant (r = 0.97, p < 0.001) correlation between Movband and Actigraph counts. The low-cost, Movband accelerometer appears to provide a valid assessment of physical activity behavior/intensity.     

Promoting additional activity in youth soccer: a half-longitudinal study on the influence of autonomy-supportive coaching and basic psychological need satisfaction

This study investigated the relationships between perceptions of coach autonomy support, basic psychological need satisfaction and the frequency at which youth soccer players engage in additional soccer activity outside of team sessions. We employed structural equation modelling to test a two-wave (T1 and T2) half-longitudinal study to see if basic psychological need satisfaction mediated the relationship between coach autonomy support and additional soccer activity across a competitive season. The sample consisted of 527 youth soccer players, aged 10–15 years. Results revealed moderate to strong temporal stability for autonomy, competence, relatedness and frequency of additional soccer activity. Furthermore, no support is offered for mediation as T1 coach autonomy support was not related to any of the three basic needs at T2 when accounting for their T1 levels. However, a positive relationship between T1 autonomy and T2 additional soccer activity emerged. This suggests that those who experience high levels of autonomy in the team setting at the start of the season report an increased frequency of additional activity at the end of the season. Results are discussed in light of the Self-Determination Theory and the Trans-Contextual Model.     

广东高职院校学生课外体育活动现状分析

通过对广东省高职学生课外体育活动开展现状的研究,发现一些体育业余组织规模小、不规范,没有充分发挥作用,课外体育活动开展中存在场地、器材不足,学习时间紧,没有养成锻炼习惯等问题,提出了鼓励组建体育俱乐部、体育锻炼小组,充分利用社会体育资源,为学校体育工作的开展提供良好的物质保证;改变传统的竞技化比赛模式,面向全体学生多开展大众化、趣味性比赛,增加选修课,改革体育课的考核办法,充分发挥学校团委、学生会及各类学生组织的作用,组织丰富多彩的课外体育活动等对策。     

Exploring the contribution of activity sports tourism to same-day visit expenditure and duration

ABSTRACT

Drawing upon a unique large-scale data source (n=5,004) and motivated by the time allocation model of consumer demand in economics, this paper critically analyses the relationship between the expenditure from, and duration of, same-day visits that comprise a large component of the domestic tourism market in England. It focusses on the contribution of activity sports tourism as a component of same-day visits. Three-stage least squares (3SLS) instrumental variable estimation is employed to account for the simultaneous determination of duration and expenditure as implied by economic theory. Controlling for socio-economic characteristics and general trip behaviours, the research identifies that although total expenditures and trip durations are positively related, there are trade-offs between these when focussing on the direct effects of the activities undertaken. However, accounting for the interrelationship between the duration of visits and the expenditures on them, it is found that walking reduces the expenditures on trips and their duration. Field sports increase them both. No effects are identified for running and cycling, as land-based activity sports tourism, or swimming and water sports, as water-based activity sports tourism. The key drivers of expenditure, which also increase the duration of trips, are visiting attractions and hospitality. The research provides a theoretically informed and empirically robust foundation for a more nuanced and targeted activity sports tourism strategy, which might have implications for how activity sports tourism may contribute to health and well-being and local economic development to better inform tourism planning and policy.     

The changing value of vigorous activity and the paradox of utilising exercise as punishment in physical education

Background: Previous research on physical education (PE) teaching practice indicates that an exercise physiology discourse has assumed a dominant position within the field. Research shows that PE teachers are likely to emphasise physical fitness training in their teaching, and PE teachers seem to appreciate pupils who show high levels of physical exertion.

Purposes: Our aim is to examine how vigorous activity/exercise is represented in the practice of PE teaching. We will also examine teaching as a discursive practice, and thereby contribute to a critical perspective on PE pedagogy.

Research design: This study was conducted in four upper secondary schools in Oslo, Norway. Data material was produced through fieldwork, during which we observed 92 PE lessons. Additionally, we conducted qualitative interviews with the eight teachers who participated in the study. Our methodological framework was discourse analysis.

Findings: Our material shows that vigorous activity plays a complex role in PE class: it can be beneficial, but it can also be punitive. The PE teachers we observed drew on an exercise physiology discourse to portray vigorous activity/exercise as beneficial and valuable to the promotion of pupils’ physical fitness and health. However, the teachers also drew on a military discourse when assigning vigorous activity to rebuke a disobedient pupil. The teachers also introduced vigorous activity in the form of additional exercise ‘punishment’, which they assigned to losers in competitive activities. In these instances, the teachers drew on exercise physiology and sports discourses. Thus, we identified how vigorous activity changed value according to context, and discuss how teachers’ use of vigorous activity as punishment can seem paradoxical in a PE setting.

Conclusion and recommendation: Our study indicates that, rather than adhering to modern educational practices, PE is rooted in ideas and practices derived from military, sports and exercise physiology discourses. PE teachers inculcated with these discourses have limited ability to discern the paradox of assigning vigorous exercise to their pupils as both a high-value activity and a punishment. PE Teacher Education should therefore problematise how teaching practice is influenced by these discourses, and facilitate discussions on how such discourses constitute PE.     

对普通高校青年教师健身活动现状的调查分析

对普通高校青年教师的健身活动现状、特点及存在的问题进行调查分析,并在此基础上进行了深入研究,旨在为高校广泛、有效地开展青年教师体育健身工作提供可行性方案,为规划高校体育发展提供相关的理论依据。     

Impact of the choice of threshold on physical activity patterns in free living conditions among adolescents measured using a uniaxial accelerometer: The HELENA study

Abstract

The aim of this study was to assess the impact of the choice of threshold on physical activity patterns measured in adolescents under free living conditions (FLC) using a uniaxial accelerometer. The study comprised 2043 adolescents (12.5–17.5 years) participating in the HELENA Study. Participants wore a uniaxial accelerometer for 7 days. The PA patterns were assessed using thresholds determined from six different studies. For each of the thresholds used, the number of adolescents fulfilling the recommendation of 60 min of moderate to vigorous PA (MVPA) per day was also calculated. A significant difference was found between thresholds regardless of the activity level: differences of 38%, 207%, 136%, and 2780% for sedentary, light, moderate, and vigorous intensity PA, respectively (P < 0.001). Time of MVPA varied between methods from 25.3 to 55.2 min · day^–1. The number of adolescents fulfilling the recommendation varied from 5.9% to 37% according to the thresholds used. The kappa coefficient for concordance in the assessment of the number of adolescents achieving the PA recommendations was generally low. The definition of the threshold for PA intensity may considerably affect the PA patterns in FLC when assessed using a uniaxial accelerometer and the number of participants fulfilling the recommendations.     

Mortality in relation to changes in physical activity in middle-aged to older Chinese: An 8-year follow-up of the Guangzhou Biobank Cohort Study

BackgroundPhysical activity (PA) is generally encouraged. Studies from developed countries in the West have shown that maintenance of adequate PA or increasing PA are associated with lower mortality risk. It is unclear whether these associations apply to an older Chinese population. Hence, we examined the changes in PA prospectively among a middle-aged and older Chinese population over an average of 4 years and explored their subsequent mortality risks.MethodsMetabolic equivalent scores of PA among participants in the Guangzhou Biobank Cohort Study were calculated. Participants were divided into 3 groups related to PA level, and changes in PA were classified into 9 categories. Information on vital status and causes of death from March 2008 to December 2012 (the first repeated examination) until December 31, 2017, was obtained via record linkage with the Death Registry.ResultsOf 18,104 participants aged 61.21 ± 6.85 years (mean ± SD), 1461 deaths occurred within 141,417 person-years. Compared to participants who maintained moderate PA, those who decreased PA from moderate or high levels to a low level had increased risks for all-cause mortality (hazard ratio (HR) = 1.47, 95% confidence interval (95%CI): 1.11–1.96). Participants who maintained a high level of PA (HR = 0.83, 95%CI: 0.70–0.98) or increased PA from low to high levels (HR = 0.71, 95%CI: 0.52–0.97) showed lower all-cause mortality risks. Those who maintained low PA levels showed a higher all-cause mortality risk, whereas those who increased their PA levels showed a non-significantly lower risk. Similar results were found for cardiovascular disease risk.ConclusionEven at an older age, maintaining a high PA level or increasing PA from low to high levels results in lower mortality risks, suggesting that substantial health benefits might be achieved by maintaining or increasing engagement in adequate levels of PA. The increased risk of maintaining a low PA level or decreasing PA to a low level warrants the attention of public health officials and clinicians.