Towards Automatic Modelling of Volleyball Players' Behavior for Analysis, Feedback and Hybrid Training

Automatic tagging of video recordings of sports matches and training sessions can be helpful to coaches and players and provide access to structured data at a scale that would be unfeasible if one were to rely on manual tagging. Recognition of different actions forms an essential part of sports video tagging. In this paper, the authors employ machine learning techniques to automatically recognize specific types of volleyball actions (i.e., underhand serve, overhead pass, serve, forearm pass, one hand pass, smash, and block which are manually annotated) during matches and training sessions (uncontrolled, in the wild data) based on motion data captured by inertial measurement unit sensors strapped on the wrists of eight female volleyball players. Analysis of the results suggests that all sensors in the inertial measurement unit (i.e., magnetometer, accelerometer, barometer, and gyroscope) contribute unique information in the classification of volleyball actions types. The authors demonstrate that while the accelerometer feature set provides better results than other sensors, overall (i.e., gyroscope, magnetometer, and barometer) feature fusion of the accelerometer, magnetometer, and gyroscope provides the bests results (unweighted average recall = 67.87%, unweighted average precision = 68.68%, and κ = .727), well above the chance level of 14.28%. Interestingly, it is also demonstrated that the dominant hand (unweighted average recall = 61.45%, unweighted average precision = 65.41%, and κ = .652) provides better results than the nondominant (unweighted average recall = 45.56%, unweighted average precision = 55.45, and κ = .553) hand. Apart from machine learning models, this paper also discusses a modular architecture for a system to automatically supplement video recording by detecting events of interests in volleyball matches and training sessions and to provide tailored and interactive multimodal feedback by utilizing an HTML5/JavaScript application. A proof of concept prototype developed based on this architecture is also described

Enhancing volleyball training:empowering athletes and coaches through advanced sensing and analysis

Modern sensing technologies and data analysis methods usher in a new era for sports training and practice. Hidden insights can be uncovered and interactive training environments can be created by means of data analysis. We present a system to support volleyball training which makes use of Inertial Measurement Units, a pressure sensitive display floor, and machine learning techniques to automatically detect relevant behaviours and provides the user with the appropriate information. While working with trainers and amateur athletes, we also explore potential applications that are driven by automatic action recognition, that contribute various requirements to the platform. The first application is an automatic video-tagging protocol that marks key events (captured on video) based on the automatic recognition of volleyball-specific actions with an unweighted average recall of 78.71% in the 10-fold cross-validation setting with convolution neural network and 73.84% in leave-one-subject-out cross-validation setting with active data representation method using wearable sensors, as an exemplification of how dashboard and retrieval systems would work with the platform. In the context of action recognition, we have evaluated statistical functions and their transformation using active data representation besides raw signal of IMUs sensor. The second application is the “bump-set-spike” trainer, which uses automatic action recognition to provide real-time feedback about performance to steer player behaviour in volleyball, as an example of rich learning environments enabled by live action detection. In addition to describing these applications, we detail the system components and architecture and discuss the implications that our system might have for sports in general and for volleyball in particular.</p

An investigation of the relationship between impact force attenuation in landing and isokinetic strength of knee muscles in individuals with different training backgrounds

Skeletal muscle is a major active mechanism of impact force attenuation in human movement. During the landing phase impact attenuation is achieved through eccentric contraction of the muscles of the lower extremity. However, few studies have investigated the effects of knee strength, especially eccentric strength, on impact attenuation during landing. Therefore the relationship was assessed in fourteen healthy, male volunteers. Seven NCAA Division I College football players (TRAINED) and seven recreationally active university students with limited sport training or competitive sport background (REC) participated in two testing sessions. Isokinetic testing of the knee extensor and flexor muscles was performed concentrically at 60 and 180 degree·sec- 1, and eccentrically at 60 degree·sec-1. 3D kinematic and ground reaction force (GRF) data were collected during drop landings from heights of 40, 60cm and 100% of each individuals maximum jump height. The TRAINED had greater concentric strength, vertical jump height, but no significant differences existed in the eccentric strength (336 vs 340 N.m/kg) between the groups. The TRAINED had marginally greater peak GRFs (2.7 & 3.5 BW vs 2.0 & 2.7 BW for 40 and 60 cm, p=0.051) and significantly less time to the peak (0.048 & 0.043 s vs 0.060 & 0.053) compared to the REC in drop landing. The TRAINED used less but non-significant knee flexion range of motion (-60.7 & -54.1 degree vs -62.7 & -69.6 degree) during drop landing than the REC. There were high, positive and significant correlations between the peak eccentric knee extensor torque and time to the first and second peak GRF. Despite all their training the results did not find any significant differences in eccentric strength of the TRAINED subjects in comparison to their REC counterparts. The TRAINED subjects adopted a stiffer landing strategy to deal effectively with high impact loading during landing. Future research is warranted in investigating impact attenuation in landing of participants with significantly different eccentric strength. KEY WORDS. Eccentric strength, dynamometer, drop landing, trainin

Die Zeitschrift Kineziologija ist dreißig Jahre jung (1971 - 2000) und zehn Jahre alt (1990 - 1999)

Three anniversaries concerning the publication of the journal Kinesiology are addressed in the paper: (a) thirty years from the first issue publication in 1971, (b) since the Journal was revived in 1992, ten volumes (1990-1999) have appeared, and (c) the Journal was recognized as international in 1995. Certain bibliometric data, regarding the editing and publishing details, and the content reviews are presented.Dieser Artikel befasst sich mit drei Jahrestagen bezüglich des Herausbringens von der Zeitschrift Kineziologija: a) dreißig Jahre seit der ersten Herausgabe im Jahre 1971, b) es wurden, seit der Wiederherausgabe im Jahre 1992, zehn Hefte (1990 - 1999) veröffentlicht, und c) die Zeitschrift wurde im Jahre 1995 als international anerkannt. Es wurden in diesem Artikel auch bestimmte bibliometrische Daten bezüglich des Edierens zusammen mit dem Überblick von Inhalten der bisher in der Zeitschrift ver6ffentlichten Artikel dargestellt

Efficacy of TAGteach Interventions: Comparing the Effects of Verbal and Audible Feedback on Skill Acquisition of Volleyball Skills

TAGteach® (based on principles of teaching with acoustical guidance) is an emerging behavioral coaching strategy that utilizes verbal instructions, visual models, and audible feedback to promote skill acquisition of a variety of skills (e.g., sports, activities of daily living, and occupational skills). Extending the findings of previous research, the current study compared the effects of audible feedback (inherent in TAGteach and verbal feedback on the skill acquisition of two volleyball skills. Five female adolescents participated in the study. Results indicated that, for all participants, implementation of TAGteach procedures (regardless of the topography of feedback), produced increases in task analysis steps performed correctly, and those increases maintained for up to two weeks. Results further indicate that performance inconsistently generalized to the natural setting (i.e., inclusion of a volleyball). Results are discussed in terms of crucial components of TAGteach and the analysis of efficient behavioral instruction. Keywords: TAGteach, sports, behavioral instruction, feedbac

Examining the assessment and development of a fundamental motor skill and the efficacy of peer teaching instructional approaches

The overall purpose of this dissertation was to examine the process of assessing and developing the Fundamental Motor Skills (FMS) of overarm throwing. This dissertation involved two foci: qualitative assessment of FMS and the efficacy of peer teaching approaches. The first focus was to contribute to qualitative assessment of FMS research by examining an assessment system commonly used to assess overarm throwing development. The second focus was to examine the efficacy of peer teaching instructional approaches on improving overarm throwing performance of pre-service physical education (PE) teachers to determine whether these approaches could facilitate pre-service PE teachers to efficiently develop FMS proficiency. PE teachers who can proficiently perform FMS are better equipped to teach these skills; their demonstrations provide the learners a “blueprint” of the skill they are trying to acquire. The research includes four separate studies. The first two studies examined Roberton’s levels (Roberton & Halverson, 1984), a qualitative assessment system used extensively for over four decades to research overarm throwing development, primarily examining the technique of children and older throwers. Study 1 attempted to validate one of the backswing sequences (Haywood et al., 1991) to authenticate it for assessing the backswing component of university-aged throwers. The findings provided preliminary support that the Haywood et al. backswing sequence, previously only validated for assessing the backswing technique of older throwers, was suitable for assessing the backswing of the university-aged throwers. Study 2 examined the impact of the follow-through on throwing velocity. Findings showed the follow-through had the second largest impact on throwing velocity of all the six components, providing preliminary support for the inclusion of the follow-through component to the existing five components of Roberton’s (Roberton & Halverson, 1984) levels, making this system more accurate and comprehensive. Study 3 and 4 both utilised a quasi-experimenal between-subjects pre-test, intervention, post-test, and retention test designs. The participants were allocated to one of three experimental groups: a Video Analysis Group (VAG), a Verbal Group (VG), and a Control Group (CG). During the interventions the VAG and VG worked in pairs in a Reciprocal style of peer teaching (Mosston & Ashworth, 2002). The VAG and VG interventions were identical except the VAG had access to video analysis technology and the CG completed unrelated course work. Study 3, a single session intervention, and Study 4, a three-session intervention, attempted to ascertain whether video analysis affects throwing technique of participants working in reciprocal peer teaching settings. The findings indicated the impact of video analysis may be dependent on the number of intervention sessions. In Study 3, video analysis in a single session intervention appeared to accelerate the participants throwing improvement. Study 4 revealed video analysis was not vital over the course of the three sessions. The VAG and VG achieved similar throwing improvements that were superior to the CG who did not experience the peer teaching intervention. The findings from this dissertation have identified scope for the Roberton’s levels (Roberton & Halverson, 1984) to be refined and the two peer teaching instructional approaches examined have been shown to be effective when trying to develop overarm throwing. Furthermore, these findings can inform Physical Education Teacher Education Programs, potentially preparing graduate PE teachers more effectively to develop their students’ FMS, which may increase the involvement of children and adolescents in sport and physical activity because they will have the necessary skills to successfully engage in these activities.Doctor of Philosoph

Changes in movement control and coordination with increasing skill in females and males

In comparisons between the sexes on movement tasks, performance outcome is emphasised with little focus upon the coordination process that underpins this. Motor skills develop through practice; differences between the sexes may therefore reflect differences in the volume of experience with a task. The first study compared groups with increasing surfing experience performing a drop-landing. Sex differences in joint angle measures were accounted for at least in part by experience. Study two investigated whether females and males achieve similar improvement from an equal volume of practice using a slalom-skiing simulator task. Over five days of practice there were no differences in rate of learning for any measure. Performance differences in some cases were attributable to anthropometric differences between the sexes that interacted with the task apparatus. Most importantly, frequency for both sexes moved towards their calculated optimal, given the task constraint meaning performance was comparable. Overall males and females showed similar initial and final performance outcomes and achieved similar gains from an equal volume of practice. The basis of coordinative structure is the coupling and correlation between elements in the motor system. Principal component analysis (PCA) can quantify these relations. A recently developed technique in PCA incorporating overall coherence was applied to kinematic and EMG signals to provide further insight into the changes in coordination that occurred with practice. There were no differences between the male and female performers again supporting the idea that with equal practice, performance is similar despite any differences in anthropometrics. Whole body movement on the skiing-simulator could be defined in a low dimensional space that was further reduced over the course of practice. Previous studies had failed to show this; hidden structure was best revealed when PCA incorporating correlation in the frequency domain was employed