Performance differences when using 26- and 29-inch-wheel bikes in Swiss National Team cross-country mountain bikers.

abstract：:Functional hypothalamic amenorrhoea (FHA) can occur due to the independent or combined effects of psychogenic and energetic stressors. In exercising women, research has primarily focused on energy deficiency as the cause of FHA while psychological stressors have been ignored. To assess both psychological and metabolic...

journal_title：Journal of sports sciences

authors： Strock NCA,De Souza MJ,Williams NI

更新日期：2020-11-01 00:00:00

abstract：:Although research into coaching has increased considerably during the last two decades, an area of neglect has been that of the professional youth coach. The aim of this study was to investigate the working behaviours of six top-level professional soccer coaches. Data were collected using a modified version of the Ari...

journal_title：Journal of sports sciences

authors： Smith M,Cushion CJ

更新日期：2006-04-01 00:00:00

abstract：:The aims of this study were to compare the physiological and anthropometric characteristics of successful mountain bikers and professional road cyclists and to re-examine the power-to-weight characteristics of internationally competitive mountain bikers. Internationally competitive cyclists (seven mountain bikers and ...

journal_title：Journal of sports sciences

authors： Lee H,Martin DT,Anson JM,Grundy D,Hahn AG

更新日期：2002-12-01 00:00:00

abstract：:A calibration study was conducted to determine the threshold counts for two commonly used accelerometers, the ActiGraph and the Actical, to classify activities by intensity in children 5 to 8 years of age. Thirty-three children wore both accelerometers and a COSMED portable metabolic system during 15 min of rest and t...

journal_title：Journal of sports sciences

authors： Evenson KR,Catellier DJ,Gill K,Ondrak KS,McMurray RG

更新日期：2008-12-01 00:00:00

abstract：:In an effort to evaluate the mechanisms underpinning performance in alpine ski racing, researchers have focused on the predictive validity of measures derived from fitness assessments. However, a limitation of this literature is the absence of practice time, since prolonged training may naturally develop specific fitn...

journal_title：Journal of sports sciences

authors： DeCouto BS,Fawver B,Taylor T,Williams AM

更新日期：2020-09-20 00:00:00

abstract：:This study aimed to compare the load-velocity and load-power relationships of three common variations of the squat exercise. 52 strength-trained males performed a progressive loading test up to the one-repetition maximum (1RM) in the full (F-SQ), parallel (P-SQ) and half (H-SQ) squat, conducted in random order on sepa...

journal_title：Journal of sports sciences

authors： Martínez-Cava A,Morán-Navarro R,Sánchez-Medina L,González-Badillo JJ,Pallarés JG

更新日期：2019-05-01 00:00:00

abstract：:This study aimed to investigate the impact of mental fatigue on soccer-specific decision-making. Twelve well-trained male soccer players performed a soccer-specific decision-making task on two occasions, separated by at least 72 h. The decision-making task was preceded in a randomised order by 30 min of the Stroop tas...

journal_title：Journal of sports sciences

authors： Smith MR,Zeuwts L,Lenoir M,Hens N,De Jong LM,Coutts AJ

更新日期：2016-07-01 00:00:00

abstract：:The purpose of this study was to examine the effects of calendar and skeletal age, anthropometric dimensions, training history and their interactions on vertical jumping height and horizontal overhead throwing velocity in a cross-section of 318 young male athletes (age range 9-16 years) participating in cross-country ...

journal_title：Journal of sports sciences

authors： Viitasalo JT,Rahkila P,Osterback L,Alén M

更新日期：1992-10-01 00:00:00

abstract：:In this study, we examined: (a) the effects of perceived motivational climate and coaching character-building competency on prosocial and antisocial behaviours towards team-mates and opponents in field hockey and netball; (b) whether the effects of perceived character-building competency on sport behaviours are mediat...

journal_title：Journal of sports sciences

authors： Boardley ID,Kavussanu M

更新日期：2009-06-01 00:00:00

abstract：:Assessments of maximal intensity exercise which determine peak power output on friction-baked cycle ergometers have fallen into two categories: correction procedures which account for changes in momentum of the ergometer's flywheel and optimization procedures which attempt to satisfy muscle force-velocity relationship...

journal_title：Journal of sports sciences

authors： Winter EM,Brown D,Roberts NK,Brookes FB,Swaine IL

更新日期：1996-12-01 00:00:00

abstract：:The aim of this study was to determine whether endurance training in athletes induces airway inflammation and pulmonary function disorders. Respiratory pattern and function were analysed in ten healthy endurance runners at rest, during sub-maximal exercise, and during the recovery. Inflammatory cells and metabolites (...

journal_title：Journal of sports sciences

authors： Denguezli M,Ben Chiekh I,Ben Saad H,Zaouali-Ajina M,Tabka Z,Abdelkrim Z

更新日期：2008-10-01 00:00:00

abstract：:Maximal oxygen uptake VO(2max)) is considered the optimal method to assess aerobic fitness. The measurement of VO(2max), however, requires special equipment and training. Maximal exercise testing with determination of maximal power output offers a more simple approach. This study explores the relationship between [Vdo...

journal_title：Journal of sports sciences

authors： Dencker M,Thorsson O,Karlsson MK,Lindén C,Wollmer P,Andersen LB

更新日期：2008-11-01 00:00:00

abstract：:The aim of this study was to examine the influence of maturity status on primary school children's physical activity and physical self-perceptions. Altogether, 175 children (97 girls, 78 boys) aged 10.6 +/- 0.3 years completed the Children and Youth Physical Self-Perception Profile and wore an ActiGraph accelerometer ...

journal_title：Journal of sports sciences

authors： Fairclough SJ,Ridgers ND

更新日期：2010-01-01 00:00:00

abstract：:The purpose of this study was to provide electromyographic feedback for (1) pedagogical advice in motor learning, (2) the ergonomics of materials choice and (3) competition. For these purposes: (1) EMG data were collected for the Stem Christie, the Stem Turn and the Parallel Christie (three basic ski initiation drills...

journal_title：Journal of sports sciences

authors： Clarys JP,Publie J,Zinzen E

更新日期：1994-06-01 00:00:00

abstract：:According to Wegner's (1994) theory of ironic processes of mental control, self-instructions not to perform in a certain way, together with mental loads, can induce thoughts, emotions, and behaviours that are precisely the opposite of intention. Wegner's theory was tested against the implicit overcompensation hypothes...

journal_title：Journal of sports sciences

authors： de la Peña D,Murray NP,Janelle CM

更新日期：2008-10-01 00:00:00

abstract：:While previous studies highlighted the importance of the different motivations for doing sports as proposed by self-determination theory, less emphasis has been put on the simultaneous presence of multiple motivations within the same individual. Therefore, the present study aimed to investigate the complex interaction...

journal_title：Journal of sports sciences

authors： Tóth-Király I,Amoura C,Bőthe B,Orosz G,Rigó A

更新日期：2020-04-01 00:00:00

abstract：:Drug abuse by adolescents has been investigated in various surveys that reported correlations between age, gender, and activity. However, none of these studies included chemical analyses to help substantiate the statements of participants. In the present study, the urine specimens of 964 students (439 females, 525 mal...

journal_title：Journal of sports sciences

authors： Thevis M,Sauer M,Geyer H,Sigmund G,Mareck U,Schänzer W

更新日期：2008-08-01 00:00:00

abstract：:We examined the effects of time of day on a cycling time trial with and without a prolonged warm-up, among cyclists who tended towards being high in "morningness". Eight male cyclists (mean +/- s: age = 24.9 +/- 3.5 years, peak power output = 319 +/- 34 W, chronotype = 39 +/- 6 units) completed a 16.1-km time trial wi...

journal_title：Journal of sports sciences

authors： Atkinson G,Todd C,Reilly T,Waterhouse J

更新日期：2005-03-01 00:00:00

abstract：:The aim of this study was to investigate the physical demands of international rugby union. Five games in the 1989-90 Five Nations Championship were analysed using video-recordings of live television transmissions. When the ball was in open play, the average running pace of players central to the action ranged from 5 ...

journal_title：Journal of sports sciences

authors： McLean DA

更新日期：1992-06-01 00:00:00

abstract：:The aim of the present study was to compare kinetically the roles of the lower extremities in generating trunk rotation in the tennis one-handed and two-handed backhand strokes. Fourteen male collegiate tennis players, seven with a preference for the one- and seven with a preference for the two-handed technique, were ...

journal_title：Journal of sports sciences

authors： Akutagawa S,Kojima T

更新日期：2005-08-01 00:00:00

abstract：:The aim of this study was to compare thoracic spine alignment with two- and three-dimensional calculations of shoulder alignment (defined as a line joining the acromion processes of the right and left scapula) when all measures were projected onto the transverse plane. A six-camera Vicon system was used to reconstruct...

journal_title：Journal of sports sciences

authors： Elliott B,Wallis R,Sakurai S,Lloyd D,Besier T

更新日期：2002-06-01 00:00:00

abstract：:The use of large cross-sectional norms on Brazilian children and youths aged 7 to 18 years within a six level competition plan helps to assess development status and monitor change. Non-athletic prototypes for comparative purposes are illustrated by the use of the lowest competitive level of 18 year olds to assess dif...

journal_title：Journal of sports sciences

authors： Matsudo VK,Rivet RE,Pereira MH

更新日期：1987-04-01 00:00:00

abstract：:This study aimed to investigate activation characteristics of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles during the acceleration and maximum-speed phases of sprinting. Lower-extremity kinematics and electromyographic (EMG) activities of the BFlh and ST muscles were examined during the accelera...

journal_title：Journal of sports sciences

authors： Higashihara A,Nagano Y,Ono T,Fukubayashi T

更新日期：2018-06-01 00:00:00

abstract：:This study used a quasi-applied research model to identify and develop potentially talented female soccer players. Athletes aged 15-19 years with a background in team ball sports or athletics were targeted for recruitment using advertisements and promotions through various media. Interested athletes attended a 2-day p...

journal_title：Journal of sports sciences

authors： Hoare DG,Warr CR

更新日期：2000-09-01 00:00:00

abstract：:There is a positive association between motor competence and physical activity in child populations. Little is known about the relative variance explained in physical activity when process- versus product-oriented approaches are used for evaluating motor competence. This study aimed to examine associations between pro...

journal_title：Journal of sports sciences

authors： Hulteen RM,True L,Pfeiffer KA

更新日期：2020-02-01 00:00:00

abstract：:The purpose of this study was to investigate the influence of shaft stiffness on grip and clubhead kinematics. Two driver shafts with disparate levels of stiffness, but very similar inertial properties, were tested by 33 golfers representing a range of abilities. Shaft deflection data as well as grip and clubhead kine...

journal_title：Journal of sports sciences

authors： MacKenzie SJ,Boucher DE

更新日期：2017-01-01 00:00:00

abstract：:The aims of the present study were to examine quantitatively ground reaction forces, kinematics, and muscle activations during the windmill softball pitch, and to determine relationships between knee valgus and muscle activations, ball velocity and muscle activation as well as ball velocity and ground reaction forces....

journal_title：Journal of sports sciences

authors： Oliver GD,Plummer H

更新日期：2011-07-01 00:00:00

abstract：:We hypothesised that habitual physical activity (PA) together with progressive endurance training contributes to the differences in training response (Δ[V(·)]O(2max)) in healthy and physically active male participants. Twenty volunteers (age 30±3 years and [V(·)]O(2max) 54±7 ml·kg⁻¹·min⁻¹) participated in an eight-wee...

journal_title：Journal of sports sciences

authors： Hautala A,Martinmaki K,Kiviniemi A,Kinnunen H,Virtanen P,Jaatinen J,Tulppo M

更新日期：2012-01-01 00:00:00

abstract：:This study aimed to verify the effect of a multicomponent intervention on cardiometabolic risk factors (CMRF), and to determine the prevalence of responders on CMRF among children and adolescents with overweight/obesity. This is a quasi-experimental study, developed with 35 children and adolescents with overweight/obe...

journal_title：Journal of sports sciences

authors： Brand C,Martins CML,Lemes VB,Pessoa MLF,Dias AF,Cadore EL,Mota J,Gaya ACA,Gaya AR

更新日期：2020-03-01 00:00:00

abstract：:To observe the associations between single nucleotide polymorphisms (SNPs) of nicotinamide N-methyltransferase (NNMT) gene and sport performance and to analyse genotype associations of the associated SNPs with sport performance and relative maximal oxygen uptake ([Formula: see text]). Participants were selected from 6...

journal_title：Journal of sports sciences

authors： Li JH,Chen W,Zhu XJ,Lin YJ,Qiu LQ,Cai CX,Wang YH,Xiong Q,Chen F,Chen LH

更新日期：2017-11-01 00:00:00