The use of behavioural objectives as a means of holding teachers to account for their students learning. Does this render student assessment ‘fit for purpose?’     

John Elliott 《European Journal of Education》2018,53(2):133-137

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Back injuries and the fast bowler in cricket     

Bruce C. Elliott 《Journal of sports sciences》2013,31(12):983-991

Here, I review research that has investigated the aetiology of injuries experienced by adolescent and adult fast bowlers. Mechanical factors play an important role in the aetiology of degenerative processes and injuries to the lumbar spine. This is particularly so in fast bowling, where a player must absorb vertical and horizontal components of the ground reaction force that are approximately five and two times body weight at front-foot and rear-foot impact, respectively. Attenuated forces are transmitted to the spine through the lower limb, while additional foces at the lumbo-sacral junction are caused by trunk hyperextension, lateral flexion and twisting during the delivery stride. Fast bowlers are classified as side-on, front-on or mixed. The mixed action is categorized by the lower body configuration of the front-on action and the upper body configuration of the side-on technique. This upper body configuration is produced by counter-rotation away from the batsman in the transverse plane about the longitudinal axis of the body of a line through the two shoulders. Counter-rotations of 12–40° during a delivery stride have predicted an increased incidence of lumbar spondylolysis, disc abnormality and muscle injury in fast bowlers. During the delivery stride, the mixed bowling action also shows: more lateral flexion and hyperextension of the lumbar spine at front-foot impact, and a greater range of motion of the trunk over the delivery stride when compared with the side-on and front-on techniques. The pars interarticularis of each vertebra is vulnerable to injury if repetitive flexion, rotation and hyperextension are present in the activity. Fast bowlers should reduce shoulder counter-rotation during the delivery stride to reduce the incidence of back injuries. When a player is required to bowl for extended periods irrespective of technique, overuse is also related to an increased incidence of back injuries and must be avoided.  相似文献   

Spot Reduction of Subcutaneous Adipose Tissue     

Arne L. Olson  Elliott Edelstein 《Research quarterly for exercise and sport》2013,84(3):647-652

Abstract

This study was designed to determine if the skinfold measurements on an exercised arm would decrease as a result of regular weight training with that arm. Thirty-two subjects completed three sets of 7-RM curls and three sets of 7-RM triceps extensions on either a daily or an alternate day schedule for a period of 6 weeks. The nonexercised arm was measured to establish the specificity of the spot reduction on the exercised arm. The results indicate that hard exercise in a specific area of the arm will result in a reduction of the subcutaneous adipose tissue in that area.  相似文献   

Effects of a short-term pre-season training programme on the body composition and anaerobic performance of professional rugby union players     

Christos K. Argus  Nicholas Gill  Justin Keogh  Will G. Hopkins  C. Martyn Beaven 《Journal of sports sciences》2013,31(6):679-686

Abstract

Pre-season rugby training develops the physical requisites for competition and consists of a high volume of resistance training and anaerobic and aerobic conditioning. However, the effects of a rugby union pre-season in professional athletes are currently unknown. Therefore, the purpose of this investigation was to determine the effects of a 4-week pre-season on 33 professional rugby union players. Bench press and box squat increased moderately (13.6 kg, 90% confidence limits ±2.9 kg and 17.6 ± 8.0 kg, respectively) over the training phase. Small decreases in bench throw (70.6 ± 53.5 W), jump squat (280.1 ± 232.4 W), and fat mass (1.4 ± 0.4 kg) were observed. In addition, small increases were seen in fat-free mass (2.0 ± 0.6 kg) and flexed upper-arm girth (0.6 ± 0.2 cm), while moderate increases were observed in mid-thigh girth (1.9 ± 0.5 cm) and perception of fatigue (0.6 ± 0.4 units). Increases in strength and body composition were observed in elite rugby union players after 4 weeks of intensive pre-season training, but this may have been the result of a return to fitness levels prior to the off-season. Decreases in power may reflect high training volumes and increases in perceived of fatigue.  相似文献   

Lumbo-pelvic loading during fast bowling in adolescent cricketers: The influence of bowling speed and technique     

Helen Crewe  Amity Campbell  Bruce Elliott 《Journal of sports sciences》2013,31(10):1082-1090

Abstract

This study aimed to assess changes in bowling technique and lumbar load over the course of a bowling spell in adolescent fast bowlers, and to investigate the relationship between lumbar loads during fast bowling and kinematic factors which have previously been associated with low back injury. Three-dimensional motion analysis was carried out on forty participants who performed an 8-over bowling spell. There were no significant changes in bowling technique or lumbar loads over the course of the spell. Bowling with a more extended front knee, faster ball release speed and increased shoulder counter-rotation were related to increased lumbo-pelvic loading – in particular peak transverse plane rotation moments and anterior-posterior shear forces. These lumbar loads may be a factor in low back injury aetiology and future studies should investigate the relationship between lumbar loading, injury incidence and other risk factors.  相似文献   

State Anxiety as a Function of Skill Level and Proximity to Competition     

Sharon Huddleston  Diane L. Gill 《Research quarterly for exercise and sport》2013,84(1):31-34

Abstract

The purpose of this study was to investigate differences between the oversized racquet and the standard-sized racquet in (1) a tennis shot accuracy test on four basic strokes (ground strokes, volley, return of serve, and serve), and (2) a measure of players' subjective evaluation of playability (control, accuracy, power, and feel). Research participants (n = 57) were undergraduate students separated into two skill levels, intermediate (n = 29) and beginners (n = 28). Data were analyzed using a two-factor ANOVA with repeated measures on one factor. Result from the skills tests indicated that both beginning and intermediate groups scores significantly higher when using the oversized racquet. The scores received when using the oversized racquet tended to reflect a general increase in all four components of the skill test, particularly the return of serve. Data indicated that the subjective evaluation of the playing characteristic of each racquet was influenced by the player's skill level. Beginning players favored the oversized racquet, yet intermediate players rated the two racquet types about equal. The investigation suggests that beginning and intermediate tennis players, educators, and tennis teaching professionals should consider using and encouraging the use of oversized racquets.  相似文献   

Development of the Sport Orientation Questionnaire     

Diane L. Gill  Thomas E. Deeter 《Research quarterly for exercise and sport》2013,84(3):191-202

Abstract

The Sport Orientation Questionnaire (SOQ) was developed as a multidimensional, sport-specific measure of individual differences in sport achievement orientation. Exploratory and confirmatory factor analyses revealed a stable, three-factor structure across three separate samples of university and high school students. The three separate but related subscales of competitiveness, win, and goal orientation demonstrate high internal consistency and stability over time. The SOQ competitiveness score differentiates students in competitive activities from those in noncompetitive activities, providing evidence for construct validity. The overall factor stability, reliability and validity evidence suggests that the SOQ can be a valuable measure for the investigation of competitiveness and achievement behavior in sport and exercise settings.  相似文献   

Competition and Instructional Set Effects On the Speed and Accuracy of a Throwing Task     

John B. Gross  Diane L. Gill 《Research quarterly for exercise and sport》2013,84(2):125-132

Abstract

Two experiments were conducted to investigate the effects of competition and instructional sets on the speed and accuracy of a dart-throwing task. In both experiments individuals competed against another subject on one day, and performed under noncompetitive conditions on a second day. The five distinct instructional sets varied from extreme emphasis on speed to extreme emphasis on accuracy. Multivariate analyses of variance revealed main effects for instructional sets on speed and accuracy in both experiments. Strong tradeoffs occurred with speed slowing and accuracy improving as the instructional emphasis changed from speed to accuracy. A competition by instructional sets interaction in Experiment 2 indicated that competition facilitated speed when speed was important, but when instructions emphasized accuracy, speed was slower in competition than in noncompetition. Accuracy was not affected by competition.  相似文献   

Laboratory versus field testing in cricket bowling: A review of current and past practice in modelling techniques     

Bruce Elliott  Jacqueline Alderson 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(1):99-108

In cricket bowling, the reconstruction of elbow angle data is of utmost importance to the bowling versus throwing argument. This paper reviews system and modelling errors inherent in three-dimensional reconstruction processes with respect to the elbow extension tolerance set by the International Cricket Council. An understanding of these factors will enable more informed decisions about the choice of in-field versus laboratory testing in the calculation of elbow extension during bowling in cricket. Although there is a paucity of objective data related to in-field and laboratory testing, biomechanists must be guided by the greater accuracy of opto-reflective than video-based systems and so testing, at least for the present, should be conducted in a laboratory setting.  相似文献   

Tennis     

Machar Reid  Bruce Elliott 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(1):47-68

The study investigated differences in the one‐ (SH) and two‐handed (DH) backhands when hit flat, across‐court (AC) and down‐the‐line (DL), and with heavy topspin DL (TDL). The ability to disguise each of these backhands when hitting the above strokes was also assessed. Eighteen college‐level male tennis players, identified as having a high performance topspin SH (n = 6) or DH (n = 12) backhand drive, participated in the study. Players were required to hit three AC, DL and TDL backhands from the baseline with their preferred technique, while being filmed with two high‐speed video cameras operating at 200 Hz. The highest horizontal velocity backhand for each stroke was analysed. Results indicated that the sequential coordination of five body segments (hips, shoulder, upper arm, forearm, and hand/racquet rotations) was required for the execution of the SH stroke. The same number of segments were generally coordinated in the DH stroke (hips, shoulders, and varying degrees of upper arm and forearm rotations followed by hand/racquet movement). Mature players produced comparable racquet horizontal velocities 0.005 s prior to impact using either the SH or DH backhand technique. The SH backhand was characterised by a more rotated shoulder alignment than the DH stroke (SH: 119.1°; DH: 83.4°) at the completion of the backswing. At impact the ball was impacted further in front (SH: 0.59 m; DH: 0.40 m) and a similar distance to the side of the body (SH: 0.75 m; DH: 0.70 m). Players using the DH backhand technique delayed the horizontal acceleration of the racquet towards the ball (SH: 0.13 s; DH: 0.08 s prior to impact) and thus were capable of displaying a similar hitting motion closer to impact than players with a SH technique.  相似文献