PubMed Journal Database | Journal of sports sciences 
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Showing PubMed Articles 1–25 of 179 from Journal of sports sciences
Abstract The present study aimed to develop a football-specific self-report instrument measuring self-regulated learning in the context of daily practice, which can be used to monitor the extent to which players take responsibility for their own learning. Development of the instrument involved six steps: 1. Literature review based on Zimmerman's ( 2006 ) theory of self-regulated learning, 2. Item generation, 3. Item validation, 4. Pilot studies, 5. Exploratory factor analysis (EFA), and 6. Confirmatory fact...
Attentional focus effects on sprint start performance as a function of skill level.
Abstract Several researchers have demonstrated that an external focus of attention (about movement's effects) during movement execution allowed better performances and learning of various motor tasks than an internal focus of attention (about movement itself). However, attentional focus effects have not been studied in tasks requiring explosive actions preceded by fast reaction time to a signal, such as a sprint start. We hypothesised that the beneficial effect of external focus of attention would be observ...
Abstract This study examined salivary cortisol and testosterone responses to two, different high-intensity, ∼30-min cycles separated by 2 h rest before and after an 11-day intensified training period. Twelve recreationally active, healthy males completed the study. Saliva samples were collected before, immediately after and 30 min after both bouts with salivary cortisol and testosterone concentrations assessed. Compared with pre-training blunted exercise-induced salivary cortisol, testosterone and corti...
Abstract Mechanical models of cycling time-trial performance have indicated adverse effects of variations in external power output on overall performance times. Nevertheless, the precise influences of the magnitude and number of these variations over different distances of time trial are unclear. A hypothetical cyclist (body mass 70 kg, bicycle mass 10 kg) was studied using a mathematical model of cycling, which included the effects of acceleration. Performance times were modelled over distances of 4-40 ...
Abstract In elite sport, to remain competitive at the international level, it is critical to understand the game demands on players to ensure sport specific training programmes are designed for optimal athlete preparation and conditioning. In netball, recent research examining the activity patterns of players at the elite level is lacking, with only one study undertaken on this level of competition in the past 30 years. Therefore, the aim of this study was to provide coaches with up to date knowledge of pla...
Mechanical properties of the triceps surae: Differences between football and non-football players.
Abstract We investigated the mechanical properties of the triceps surae between professional, junior, and non-football players. Fifty-nine men participated in this study. The mechanical properties of the right legs' triceps surae were measured in vivo using a free oscillation technique; no significant differences existed between the groups. The mean results for musculo-articular stiffness, damping coefficient, and damping ratio were as follows: professional football players (21523 N· m(-1), 330.8 N · s ·...
Abstract Practice plays an important role in skill acquisition, although not all practice is of equal quality. We examined the types of team practice activities in four groups of youth cricket players. The groups were recreational- and elite-children (9 to 12 years of age) and recreational- and elite-adolescent players (13 to 17 years of age). Time motion analysis recorded the duration in two types of practice activities, namely, Training Form and Playing Form. Training Form is mainly drill-type activities,...
Abstract To better understand the cascade from neural activation up to force production within in vivo contracting muscle-tendon units, we estimated activation of contractile elements from experimentally measured human fascicle length change and force using a Hill-type muscle model. The experiment was conducted with respect to twitch contractions of the tibialis anterior muscle at three joint angles. As muscle contractile element force is a function of its length and velocity, the activation of contractile...
Analysis of lower limb internal kinetics and electromyography in elite race walking.
Abstract The aim of this study was to analyse lower limb joint moments, powers and electromyography patterns in elite race walking. Twenty international male and female race walkers performed at their competitive pace in a laboratory setting. The collection of ground reaction forces (1000 Hz) was synchronised with two-dimensional high-speed videography (100 Hz) and electromyography of seven lower limb muscles (1000 Hz). As well as measuring key performance variables such as speed and stride length, norma...
Abstract The present research was designed to evaluate the adaptive responses to oxidative stress and inflammation in handball players subjected to well-controlled training intervals over one-year of competition. Seven blood samples were collected over the season of the study, approximately one a month. Plasma lipid peroxidation, nitrite, cytokines (IL-1β, IL-6, INFγ and TNFα), and the glutathione cycle in erythrocytes, were measured. Exercise intensity, measured with the Borg's scale, increased signific...
Abstract This study examines factors that lead to winning matches in men's singles Grand Slam tennis, and proposes guidelines for coaches and professional tennis players both in training and preparation for Grand Slam competitions. Using longitudinal data between 1991 and 2008 retrieved from the official website of the Association of Tennis Professionals, we analysed player performance over 9,144 matches in men's singles Grand Slam tournaments. To predict match outcome, 16 variables were classified into one...
Influence of playing standard on the physical demands of professional rugby league.
Abstract In this paper we report on two studies that investigated the physical demands of professional rugby league match-play. Instudy one, National Rugby League (NRL) and National Youth Competition (NYC) players underwent global positioning system (GPS) analysis during competitive matches. No differences (P > 0.05) were observed between playing standards for minutes played, total distance covered, or the distances covered at low and high speeds. However, NRL players engaged in significantly more repeate...
Abstract Sports clubs create conditions for people of all ages to pursue a healthy lifestyle through exercise in sports and attend to constructive pedagogical work which creates much value for society. This study investigates the relationship between adolescents' sports clubs participation and self-reported mental and physical conditions and future expectations. The participants were 10,987 pupils in the final three years of their compulsory education in Iceland (aged 14-16 years). The participants complete...
The potential use and abuse of thymosin β-4 in sport and exercise science.
Effect of target change during the simple attack in fencing.
Abstract The aim of this study was to test the effect that changing targets during a simple long lunge attack in fencing exerts on the temporal parameters of the reaction response, the execution speed, and the precision and the coordination of the movement pattern. Thirty fencers with more than 10 years of experience participated in this study. Two force platforms were used to record the horizontal components of the reaction forces and thereby to determine the beginning of the movement. A three-dimensional...
Does gymnastics practice improve vertical jump reliability from the age of 8 to 10 years?
Abstract The objective of this study was to confirm whether gymnastics practice from a young age can induce greater vertical jump reliability. Fifty young female gymnasts (8.84 ± 0.62 years) and 42 females in the control group (8.58 ± 0.92 years) performed the following jump tests on a contact mat: squat jump, countermovement jump, countermovement jump with arm swing and drop jump from heights of 40 and 60 cm. The two testing sessions had three trials each and were separated by one week. A 2 (groups)...
Abstract Affordances mean opportunities for action. These affordances are important for sports performance and relevant to the abilities developed by skilled athletes. In racquet sports such as badminton, different players prefer widely different string tension because it is believed to provide opportunities for effective strokes. The current study examined whether badminton players can perceive the affordance of string tension for power strokes and whether the perception of affordance itself changed as a f...
Abstract Decision tree induction is a novel approach to exploring attacker-defender interactions in many sports. In this study hockey was chosen as an example to illustrate the potential use of decision tree inductions for the purpose of identifying and communicating characteristics that drive the outcome. Elite female players performed one-versus-one contests (n = 75) over two sessions. Each contest outcome was classified as either a win or loss. Position data were acquired using radio-tracking devices,...
Abstract The aim of this study was to examine the effect of a 10-week combined resistance/sprint training programme in the post-activation potentiation of sprint performance before, between and after resistance training sets. Twenty-six junior basketball players were randomly divided into a control and a combined training group. The combined training group performed a combined training programme consisting of 5 sets at 5-8 RM (Repetition Maximum) half-squats with sprints performed between each set. Post-act...
Personal and situational factors influencing coaches' perceptions of stress.
Abstract Coaching has been recognised as a demanding occupation, associated with a range of stressors. The extent to which coaches perceive stress is likely to be influenced by various personal and situational factors. The purpose of this study was to identify coaches' levels of perceived stress and examine the personal and situational factors that may influence coaches' perceptions of stress. In total, 502 coaches working with university, college, Canada Games, and/or nationally identified athletes complet...
A sit-ski design aimed at controlling centre of mass and inertia.
Abstract This article introduces a sit-ski developed for the Canadian Alpine Ski Team in view of the Vancouver 2010 Paralympic games. The design is predominantly based on controlling the mass distribution of the sit-ski, a critical factor in skiing performance and control. Both the antero-posterior location of the centre of mass and the sit-ski moment of inertia were addressed in our design. Our design provides means to adjust the antero-posterior centre of mass location of a sit-ski to compensate for masse...
Quantifying the nature of anticipation in professional tennis.
Abstract We quantify the nature and frequency of anticipation behaviours in professional tennis using video coding of incidents where the time delay between the opponent's stroke and the reaction of the player were recorded. We argue that anticipation is based on uncertain information and should lead in some situations to erroneous decisions. We identified the transition between reaction (with 100% accuracy in the selection of where the ball is played on the court) and anticipation (with less than 100% accu...
Somatotyping using 3D anthropometry: a cluster analysis.
Abstract Somatotyping is the quantification of human body shape, independent of body size. Hitherto, somatotyping (including the most popular method, the Heath-Carter system) has been based on subjective visual ratings, sometimes supported by surface anthropometry. This study used data derived from three-dimensional (3D) whole-body scans as inputs for cluster analysis to objectively derive clusters of similar body shapes. Twenty-nine dimensions normalised for body size were measured on a purposive sample of...
How gender and task difficulty affect a sport-protective response in young adults.
Abstract We tested the hypotheses that gender and task difficulty affect the reaction, movement, and total response times associated with performing a head protective response. Twenty-four healthy young adults (13 females) performed a protective response by raising their hands from waist level to block a foam ball fired at their head from an air cannon. Participants initially stood 8.25 m away from the cannon ('low difficulty'), and were moved successively closer in 60 cm increments until they failed to b...
Abstract The aims of this study were to examine the 1) individual playing area, 2) length and width of the rectangle encompassing the individual playing area and 3) distance between the goalkeepers and their nearest team-mates during professional soccer matches and compare these to previously reported pitch sizes for small-sided games (SSGs). Data were collected from four Spanish La Liga matches of the 2002-03 season, and notated post-event using the Amisco® system. The pitch sizes obtained from real match...
