论我国保龄球运动经营现状与发展趋势

为保证我国保龄球运动健康发展,促进保龄球运动水平的不断提高,本文就目前国内保龄球馆的经营现状与保龄球运动的发展趋势进行分析探讨,以求得到各界同仁的关心与重视     

保龄球计分系统的硬件实现

保龄球设备价格昂贵,这几年进口所费累计已近８０ 亿人民币。其中重要的计分系统又均是美国、加拿大、南韩设计的,且还存有不足之处。随着计算机的发展,我们完全可以开发出既符合国际标准又适应国情的新型计分系统     

Back injuries and the fast bowler in cricket

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.     

对上海市保龄球馆经营的研究

通过采用问卷调查和实地走访的方法。提出认为,目前上海市经营性保龄球馆已从高涨期走向平稳发展期,正处在市场发展的成熟阶段,虽然球馆间竞争十分激烈,发展速度减慢,但这是正常的经济现象。在分析了影响保龄球馆经营的内因、外因并提出若干方面的对策后,得出上海市保龄球市场还有发展潜力的结论。     

The effect of labels and instruction on concept attainment in the educable mentally retarded

The present experiment examined concept attainment in 80 educable mentally retarded and 80 normal boys of high and low mental age. The concept of an equilateral triangle was assessed following random exposure to one of four experimental conditions assessing the influence of verbal labels and instruction on the labels. A 2 × 2 × 4 multivariate analysis of variance revealed a significant effect of mental age; however, retarded and normal subjects did not differ in mean performance on any of the five dependent measures. The hypothesized treatment effect was significant at the formal level of concept attainment. The findings were discussed in terms of theoretical and educational implications.     

我国保龄球运动发展现状与对策的研究

通过调查和查阅献资料探讨我国保龄球发展状况，结果表明保龄球运动在我国开展时间短，发展很快，在20世纪90年代的中后期形成了一股势不可挡的热潮。如何进行规范化管理；努力提高竞技水平；走实体化和职业化的路子是今后发展我国保龄球运动的关键所在，旨为我国保龄球运动进一步发展，提供理论参考依据。     

An evaluation of biomechanical measures of bowling action legality in cricket

Cricket bowling is traditionally thought to be a rigid-arm motion, allowing no elbow straightening during the delivery phase. Conversely, research has shown that a perfectly rigid arm through delivery is practically unattainable, which has led to rule changes over the past years. The current rule requires a bowler not to increase the elbow angle by more than 15°, thus requiring a measurement to confirm legality in “suspect” bowlers. The aims of this study were to evaluate whether the current rule is maintained over a range of bowlers and bowling styles, and to ascertain whether other kinematics measures may better differentiate between legal and suspect bowling actions. Eighty-three bowlers of varying pace were analysed using reflective markers and a high-speed (240 Hz) eight-camera motion analysis system in a laboratory. The change in elbow segment angle (minimum angle between the arm and forearm), the change in elbow extension angle with respect to the flexion–extension axis of a joint coordinate system, and the elbow extension angular velocity at ball release were measured. We found that bowlers generally bowled within a change in elbow extension angle of 15°. However, this limit was unable to differentiate groups of bowlers from those who were suspected of throwing in the past. Improved differentiation was attained using the elbow extension angular velocity at ball release. The elbow extension angular velocity at ball release may be conceptually more valid than the elbow extension angle in determining which bowlers use the velocity-contributing mechanisms of a throw. Also, a high value of elbow extension angular velocity at ball release may be related to the visual impression of throwing. Therefore, it is recommended that researchers and cricket legislators examine the feasibility of specifying a limit to the elbow extension angular velocity at ball release to determine bowling legality.     

Cricket bowling deliveries and the discrimination ability of professional and amateur batters

Bowlers in cricket try to disguise their bowling action by movement pattern similarity. The batter’s task is, therefore, to solve rapidly perceptual discrimination problems. Previous research has suggested that batters can discriminate perceptual cues that provide depth or target information. However, at present, there is a lack of applied research evidence on further perceptual cue utilization, including bowling delivery identification. This ability is required when batting against wrist-spin bowlers who may use five different types of delivery. In the present study, we assessed this perceptual discrimination ability among three distinct standards of batters. In addition, the relative potency of body action and ball flight information was assessed by visual occlusion techniques. We found that more expert batters in general showed greater perceptual discrimination skills when faced with different ball types. However, this discrimination ability was linked specifically to delivery type and to previous experience. We also found that additional ball flight information provided no more advantage to this discrimination ability. This finding reinforces the importance of advanced cue information and the need to expose cricket batters to different bowling actions. Further study of the development of movement pattern recognition is recommended.     

Simultaneous measurement of back and front foot ground reaction forces during the same delivery stride of the fast-medium bowler

Six male cricket bowlers (mean - s x ¥ : age 23.5 - 1.3 years; height 1.83 - 0.04 m; body weight 826 - 20 N) performed their typical bowling action at a set of stumps positioned at standard pitch length (20.1 m). A specially designed force platform rig allowed the correct positioning of two force platforms to be achieved beneath an outdoor polyflex runway (0.017 m depth) for each player's delivery stride pattern. For the back foot, the peak vertical ground reaction force was 1.95 - 0.08 kN (2.37 - 0.14 BW) and the braking force was 0.77 - 0.12 kN (0.94 - 0.16 BW). For the front foot, the peak vertical force was 4.80 - 0.92 kN (5.75 - 0.98 BW) and the braking force was 2.93 - 0.56 kN (3.54 - 0.67 BW). The mean peak vertical loading rate for front foot contact was 205 - 52.8 kN·s -1 (249 - 64 BW·s -1 ) with mean values ranging from 81 to 446 kN·s -1 (98 to 540 BW·s-1). The range for back foot contact was much smaller, 25-70 kN·s -1 (30-85 BW·s -1 ), with a mean of 41.7 - 7.10 kN·s -1 (50.6 - 8.6 BW·s -1 ). Mean peak impact occurred 24 ms after touchdown for the back foot and 16 ms after touchdown for the front foot. At impact, mean peak loading rates were greater for the front foot at 246 kN·s -1 (298 BW·s -1 ), with a range of 80-483 kN·s -1 (98-534 BW·s -1 ), than for the back foot at 65 kN·s -1 (79 BW·s -1 ), with a range of 40-84 kN·s -1 (49-110 BW·s -1 ).     

Cricket fast bowling performance and technique and the influence of selected physical factors during an 8-over spell

The aims of this study were to determine the influence of an 8-over spell on cricket fast bowling technique and performance (speed and accuracy), and to establish the relationship of selected physical capacities with technique and performance during an 8-over spell. Fourteen first-grade fast bowlers with a mean age of 23 years participated in the study. Physical capacities assessed were abdominal strength, trunk stability, selected girth and skinfold measures. During the delivery stride, bowlers were filmed from an overhead and lateral perspective (50 Hz) to obtain two-dimensional data for transverse plane shoulder alignment and sagittal plane knee joint angle respectively. Ball speed was measured by a radar gun and accuracy by the impact point of each delivery on a zoned scoring target at the batter's stumps. Shoulder counter-rotation did not change significantly between overs 2 and 8 for all bowlers, but was significantly related to a more front-on shoulder orientation at back foot impact. When the front-on fast bowlers ( n = 5) were isolated for analysis, shoulder counter-rotation increased significantly between overs 2 and 8. Ball speed remained constant while accuracy showed some non-significant variation during the spell. Shoulder counter-rotation was significantly related to accuracy scores during the second half of the 8-over spell. Chest girth and composition and body composition were significantly related to ball release speed at various times during the spell.