University of Canberra Research Institute for Sport and Exercise (UCRISE), University of Canberra, Canberra, ACT, Australia.
Discipline of Sport and Exercise Science, Faculty of Health, University of Canberra, Canberra, ACT, Australia.
Scand J Med Sci Sports. 2018 Jun;28(6):1691-1699. doi: 10.1111/sms.13070. Epub 2018 Feb 27.
With advances in technology, scientists are now able to more accurately measure elbow displacement changes during the cricket bowling action. This has led to the realization that the majority of bowlers undergo some degree of elbow extension during the forward swing phase of bowling. Consequently, the International Cricket Council were obliged to revise the once zero tolerance for elbow extension threshold to a 15° range. However, it is still not understood if bowling with >15° of elbow extension aids performance or alters other kinematic movements. The purpose of this study was to compare performance and technique measures between legal and illegal finger-spin bowlers. Data were collected from 48 pathway and elite bowlers using a 22-camera motion analysis system. Results indicated that the ball velocity and revolutions at ball release of pathway bowlers with illegal actions showed no significant difference and were similar to elite legal bowlers. Technique differences were also identified, with illegal bowlers being more front-on, forcing a reliance on increased elbow flexion and supination to impart effective ball kinematics at ball release. The performance benefit of greater ball velocity and revolutions is obtained when finger-spin bowlers deliver the ball with more than the allowable 15° of elbow extension, thus reinforcing the validity of the current bowling laws. To counteract bowling with an illegal action, it is recommended that a more side-on technique at back foot impact and rotating the trunk through to the point of ball release will assist bowlers in reducing undesirable elbow extension levels.
随着技术的进步，科学家现在能够更准确地测量板球投球动作中的肘部位移变化。这使得人们意识到，大多数投球手在投球的前摆阶段都会经历一定程度的肘部伸展。因此，国际板球理事会不得不将曾经对肘部伸展的零容忍阈值修改为 15°的范围。然而，目前仍不清楚是否存在大于 15°的肘部伸展可以提高表现或改变其他运动学动作。本研究的目的是比较合法和非法手指旋转投球手的表现和技术指标。使用 22 个摄像头运动分析系统收集了来自 48 名投球手的路径和精英投球手的数据。结果表明，动作违规的投球手在球速和投球时的旋转方面与精英合法投球手没有显著差异。还发现了技术上的差异，违规投球手更面向正面，迫使他们依赖增加的肘部弯曲和旋前，以在投球时有效地赋予球运动学。当手指旋转投球手投球时，肘部伸展超过允许的 15°时，会获得更大的球速和旋转的性能优势，从而加强了现行投球法的有效性。为了对抗违规投球，建议在脚后跟着地时采用更侧身的技术，并通过转动躯干到投球点，以帮助投球手降低不希望出现的肘部伸展水平。
