Constraints on interceptive actions in cricket
Movement scientists are continually searching to enhance our understanding of human movement. Recent research has begun to examine representative movement models from sport to demonstrate how individual, environments and task constraints interact to shape movement behaviour. The series of studies in this doctoral thesis aimed to: (1) provide an enhanced theoretical understanding of the constraints on interceptive actions by focussing on movements from cricket; and (2) provide practitioners with applied research findings that can underpin effective pedagogical practice. Initial examination of the discrete interceptive action of cricket batting demonstrated that perception and action is constrained by an interaction of batting skill and bowling action information. Specifically, perceptual discrimination was shown to be more complex than previously thought. Initial findings demonstrated that more expert batters were able to utilise information from within bowler’s actions in order to determine the spin type deliveries of expert wristspin bowlers. Conversely, club level players were not able to use this information. Further analysis revealed that idiosyncrasies within bowlers’ actions also impacted on discrimination ability. The unique delivery actions for specific spin ball types resulted in differences in discrimination ability of the national and club level players. Ability to identify ball type was also constrained by the availability of different information sources; more familiar ball types or those ball types with distinctive flight characteristics could be identified with ball flight only, whereas ball types that were less familiar or had less distinctive flight patterns required access to body action information. Finally, national-level players were able to utilise ball flight information to reach performance levels above those of club players when body action and ball flight information were available. This factor has important implications for the development of perceptual training programmes. Given these findings, the usefulness of bowling machines for developing appropriate information: movement couplings are brought into question. Therefore, movement analysis of four high-intermediate level batters batting against a bowling machine and bowler of the same speed information was undertaken. Results demonstrated that removing information on body action led to changes in the timing and coordination of the forward defensive shot. Specifically, this was caused by changes in the bat swing as batters tried to time their initial movements to ball release in the bowling machine condition. Using the bowling machine did not lead to a catastrophic breakdown in performance, but did lead to poorer technique. The results emphasised the importance of practice organisation which maintains specific information: movement couplings and provided additional support for the prospective control of human movements. Taken together, the findings from these studies suggest that more expert players should avoid the use of bowling machines during practice. Conversely, less skilled player’s movement patterns may be less influenced by their use as they cannot utilise bowler’s action information, although practice use should be restricted after basic coordination patterns have been established. Analysis of locomotor pointing strategies of six professional bowlers was undertaken to elucidate control mechanisms. Results revealed that despite highly inconsistent starting points, bowlers achieved levels of variability (0.08 m-0.16 m) at the bound step consistent with those seen in international long jumpers hitting the take-off board. Inter- and intra-step analyses revealed that bowlers were able to regulate their steps as and when required to throughout the whole approach. This regulation strategy only continued while it was required. Results provide support for prospective control of locomotion, as well as providing further evidence that the nested task constraint at the end of the run-up, in conjunction with the availability of vertical reference information in the vicinity of the take-of area results in different control strategies than previously observed in earlier studies. This thesis has contributed knowledge regarding the theoretical understanding of how interaction of individual, environmental and task constraints underpin both discrete and continuous interceptive actions. For the first time perceptual discrimination capability in cricket batting has been shown to be a function of an interaction between batting skill and bowler movement patterns. Additionally, when batters are not able to use the information sources provided by the bowler, different coordination and timing patterns were observed during performance, supporting a prospective control explanation of movement control in cricket batting. The thesis has provided new evidence to show that task and environmental constraints determine movement strategies in locomotor pointing of cricket bowling. Bowlers’ run-ups were found to be visually regulated from very early steps and that steps were adjusted as and when required throughout the whole of the run-up. The theoretical findings of the thesis have some important practical applications. Application of these findings would fundamentally change the way that both sport science support and coaching is delivered. Future studies need to explore how manipulating constraints can enhance batting and bowling performance.