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Jonathon Weakley Shaun McLaren Carlos Ramirez-Lopez Amador García-Ramos Nick Dalton-Barron Harry Banyard 《Journal of sports sciences》2020,38(5):477-485
ABSTRACTThe aim of this study was to investigate the differences and long-term reliability in perceptual, metabolic, and neuromuscular responses to velocity loss resistance training protocols. Using a repeated, counterbalanced, crossover design, twelve team-sport athletes completed 5-sets of barbell back-squats at a load corresponding to a mean concentric velocity of ~0.70 m·s?1. On different days, repetitions were performed until a 10%, 20% or 30% velocity loss was attained, with outcome measures collected after each set. Sessions were repeated after four-weeks. There were substantial between-protocol differences in post-set differential ratings of perceived exertion (dRPE, i.e., breathlessness and leg muscles, AU) and blood lactate concentration (B[La], mmol·L?1), such that 30%>20%>10% by small to large magnitudes. Differences in post-set countermovement jump (CMJ) variables were small for most variables, such that 30%<20%<10%. Standard deviations representing four-week variability of post-set responses to each protocol were: dRPE, 8–11; B[La], 0.8–1.0; CMJ height, 1.6–2.0; CMJ PPO, 1.0–1.8; CMJ PCV, 0.04–0.06; CMJ 100ms-Impulse, 5.7–11.9. Velocity loss thresholds control the magnitude of perceptual, metabolic, and neuromuscular responses to resistance training. For practitioners wanting to reliably prescribe training that can induce a given perceptual, metabolic, or neuromuscular response, it is strongly advised that velocity-based thresholds are implemented. 相似文献
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Domesticating Computers and the Internet 总被引：1，自引：0，他引：1
The people who use computers and the ways they use them have changed substantially over the past 25 years. In the beginning highly educated people, mostly men, in technical professions used computers for work, but over time a much broader range of people are using computers for personal and domestic purposes. This trend is still continuing, and over a shorter time scale has been replicated with the use of the Internet. This paper uses data from four national surveys to document how personal computers and the Internet have become increasingly domesticated since 1995 and to explore the mechanisms for this shift. Now people log on more often from home than from places of employment and do so for pleasure and for personal purposes rather than for their jobs. Analyses comparing veteran Internet users to novices in 1998 and 2000 and analyses comparing the change in use within a single sample between 1995 and 1996 support two complementary explanations for how these technologies have become domesticated. Women, children, and less well-educated individuals are increasingly using computers and the Internet and have a more personal set of motives than well-educated men. In addition, the widespread diffusion of the PC and the Internet and the response of the computing industry to the diversity in consumers has led to a rich set of personal and domestic services. 相似文献
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Rats searched for food that was contingent on time and place in an open field. One location was active at a time, the active location moved in a clockwise direction after each reward, and each location was repeated several times on each daily session. When a location was active, the first response after a fixed interval produced food. The intervals associated with each of the four locations were consistently 60, 30, 30, and 60 sec. For independent groups, inspecting an inactive location had no consequence (n = 7) or reduced the amount of food delivered at the active location (n = 6). The rates of inspecting active and inactive locations increased before the associated intervals elapsed, with preferential responding at the active locations. Rates of anticipation at active locations failed to superimpose when plotted as a function of proportional time. Simultaneous temporal and spatial processing contributed to the failure of proportional timing. 相似文献
5.
Helen R. Johnson Margaret J. J. Thompson Suzanne Wilkinson Louise Walsh Jonathon Balding Victoria Wright 《教育心理学》2002,22(5):553-556
Twenty five class teachers completed a "Strengths and Difficulties" assessment for 523 children aged from 7 to 11 years of age. Children self-completed a 39-item "My Life in School" questionnaire. One third of the sample were self-reported victims of bullying behaviour. Boys with poor prosocial skills, emotional problems and general difficulties with social interaction, expression of emotion and hyperactivity were at greatest risk of being bullied. There was no significant effect of age. The data support previous research findings that gender influences the prevalence of bullying but not that younger children are more vulnerable. This study provides new evidence that teachers recognise social behaviour and interactions that can significantly affect whether primary school children are bullied. 相似文献
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This paper investigates the relationship between defensive communication in performance appraisal settings by considering the mediating effect of leader–member exchange relationships. In a study of employees of a US federal fire department, defensive communication was associated with lower quality leader–member exchange relationships, which in turn was related to burnout. We discuss the implications of these findings, particularly as they apply to organizations and their employees, as well as limitations and directions for future research. 相似文献
7.
Jonathon Sargeant 《Education 3-13》2013,41(2):190-200
This paper presents the findings of a study of the perspectives of Australian, English and New Zealand ‘tweens’ in response to one question, ‘what makes people muck up at school?’ Arguing for the increased prioritisation of children's voices in educational planning and provision, this paper provides, in children's own words, their perspectives on school success and classroom dynamics. 相似文献
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Henry Currall (ed.) Phonograph Record Libraries: Their Organization and Practice (Hamden, Conn.: Archon Books, 1971 —price not known) Jonathon Miller's Marshall McLuhan (New York: Viking Press “Modern Masters” series, 1971—$1.75, paper) 相似文献
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Myles W. O’Brien Jarrett A. Johns Jonathon R. Fowles Derek S. Kimmerly 《Measurement in physical education and exercise science》2020,24(2):147-156
ABSTRACTThe activPAL is a widely-used measure of sedentary time but few studies have evaluated its ability to estimate physical activity intensity. This study determined the accuracy of the algorithm used by the activPAL to predict metabolic equivalents (METs) from cadence and a curvilinear cadence-METs equation individualized for height. Thirty-six healthy adults (25 ± 6 years) completed a progressive walking protocol. Stepping cadence was video recorded and METs were determined via indirect calorimetry. Manually-counted cadence was input into the activPAL and curvilinear equations. The internal activPAL equation overpredicted METs at slower cadences (<120 steps/minute) but underpredicted METs at faster cadences (>120 step/minute) (proportional bias, p < .001). Conversely, the curvilinear equation exhibited neither fixed (p = .37) nor proportional bias (p = .07), and a lower absolute MET difference [0.87 ± 0.65 (range:0.0–3.2) vs. 0.56 ± 0.45 (range:0.0–2.7) METs]. The linear activPAL equation poorly estimates METs from stepping cadence but these inaccuracies may be lessened through the use of an individualized curvilinear equation. 相似文献
10.
Gregory Roe Joshua Darrall-Jones Kevin Till Padraic Phibbs Dale Read Jonathon Weakley 《European Journal of Sport Science》2017,17(6):647-655
Repeated physical contact in rugby union is thought to contribute to post-match fatigue; however, no evidence exists on the effect of contact activity during field-based training on fatigue responses. Therefore, the purpose of this study was to examine the effect of contact during training on fatigue markers in rugby union players. Twenty academy rugby union players participated in the cross-over study. The magnitude of change in upper- and lower-body neuromuscular function (NMF), whole blood creatine kinase concentration [CK] and perception of well-being was assessed pre-training (baseline), immediately and 24?h post-training following contact and non-contact, field-based training. Training load was measured using mean heart rate, session rating of perceived exertion (sRPE) and microtechnology (Catapult Optimeye S5). The inclusion of contact during field-based training almost certainly increased mean heart rate (9.7; ±3.9%) and sRPE (42; ±29.2%) and resulted in likely and very likely greater decreases in upper-body NMF (?7.3; ±4.7% versus 2.7; ±5.9%) and perception of well-being (?8.0; ±4.8% versus ?3.4; ±2.2%) 24?h post-training, respectively, and almost certainly greater elevations in [CK] (88.2; ±40.7% versus 3.7; ±8%). The exclusion of contact from field-based training almost certainly increased running intensity (19.8; ±5%) and distance (27.5; ±5.3%), resulting in possibly greater decreases in lower-body NMF (?5.6; ±5.2% versus 2.3; ±2.4%). Practitioners should be aware of the different demands and fatigue responses of contact and non-contact, field-based training and can use this information to appropriately schedule such training in the weekly microcycle. 相似文献