Efforts at player motion tracking have traditionally involved a range of data collection techniques from live observation to post-event video analysis where player movement patterns are manually recorded and categorized to determine performance effectiveness. Due to the considerable time required to manually collect and analyse such data, research has tended to focus only on small numbers of players within predefined playing areas. Whilst notational analysis is a convenient, practical and typically inexpensive technique, the validity and reliability of the process can vary depending on a number of factors, including how many observers are used, their experience, and the quality of their viewing perspective. Undoubtedly the application of automated tracking technology to team sports has been hampered because of inadequate video and computational facilities available at sports venues. However, the complex nature of movement inherent to many physical activities also represents a significant hurdle to overcome. Athletes tend to exhibit quick and agile movements, with many unpredictable changes in direction and also frequent collisions with other players. Each of these characteristics of player behaviour violate the assumptions of smooth movement on which computer tracking algorithms are typically based. Systems such as TRAKUS, SoccerMan, TRAKPERFORMANCE, Pfinder and Prozone all provide extrinsic feedback information to coaches and athletes. However, commercial tracking systems still require a fair amount of operator intervention to process the data after capture and are often limited by the restricted capture environments that can be used and the necessity for individuals to wear tracking devices. Whilst some online tracking systems alleviate the requirements of manual tracking, to our knowledge a completely automated system suitable for sports performance is not yet commercially available. Automatic motion tracking has been used successfully in other domains outside of elite sport performance, notably for surveillance in the military and security industry where automatic recognition of moving objects is achievable because identification of the objects is not necessary. The current challenge is to obtain appropriate video sequences that can robustly identify and label people over time, in a cluttered environment containing multiple interacting people. This problem is often compounded by the quality of video capture, the relative size and occlusion frequency of people, and also changes in illumination. Potential applications of an automated motion detection system are offered, such as: planning tactics and strategies; measuring team organisation; providing meaningful kinematic feedback; and objective measures of intervention effectiveness in team sports, which could benefit coaches, players, and sports scientists.

27Purpose: Previous research demonstrating that specific performance outcome goals can be 28 achieved in different ways is functionally significant for springboard divers whose 29 performance environment can vary extensively. This body of work raises questions over the 30 traditional approach of balking (terminating the take-off) by elite divers aiming to perform 31 only identical, invariant movement patterns during practice. Method: A 12-week training 32 program (two times per day; 6.5 hours per day), was implemented with four elite female 33 springboard divers to encourage them to adapt movement patterns under variable take-off 34 conditions and complete intended dives, rather than balk. suggested that, on completion of training, athletes were capable of successfully adapting their 45 movement patterns under more varied take-off conditions, to achieve greater consistency and 46 stability of performance outcomes. 47 48

Two distinctly separate training facilities (dry-land and aquatic) are routinely used in springboard diving and pose an interesting problem for learning, given the inherent differences in landing (head first vs. feet first) imposed by the different task constraints. Although divers may practise the same preparation phase, take-off and initial aerial rotation in both environments, there is no evidence to suggest that the tasks completed in the dry-land training environment are representative of those performed in the aquatic competition environment. The aim of this study was to compare the kinematics of the preparation phase of reverse dives routinely practised in each environment. Despite their high skill level, it was predicted that individual analyses of elite springboard divers would reveal differences in the joint coordination and board-work between take-offs. The two-dimensional kinematic characteristics were recorded during normal training sessions and used for intra-individual analysis. Kinematic characteristics of the preparatory take-off phase revealed differences in board-work (step lengths, jump height, board depression angles) for all participants at key events. However, the presence of scaled global topological characteristics suggested that all participants adopted similar joint coordination patterns in both environments. These findings suggest that the task constraints of wet and dry training environments are not similar, and highlight the need for coaches to consider representative learning designs in high performance diving programmes.

This study aimed to explore the experiential knowledge and preferred training approaches of elite swimming coaches in regards to general skill development and then looking specifically at the freestyle stroke. A qualitative thematic analysis approach was employed to identify, analyse and report themes within the content of the collected data. Twenty elite swimming coaches participated in semi-structured interviews. Several themes revealed that the most common training practices employed to improve skill learning included the use of task decomposition (part-task) techniques. The findings also indicated that swimming coaches believe practice should be specific / representative to the intended performance outcomes. It is believed that such viewpoints may have been influenced by coaches' interaction with skill acquisition consultants and may have also shaped some coaches use of variants of constraints manipulation in their practice design. While swimming coaches seem to mix both traditional and contemporary skill acquisition theories in their training prescriptions, the traditional approach is dominant as evidenced by coaches seeking to reinforce "perfect" swimming technique and mechanical consistency.Considering coaches' experiential knowledge and training prescriptions may benefit future research protocols and better facilitate the transfer of empirical findings to coaching practice.