3D biomechanics of rugby tackle techniques to inform future rugby research practice : a systematic review

Background The tackle is the most common in-play event in rugby union and rugby league (the rugby codes). It is also associated with the greatest propensity for injury and thus accounts for the most injuries in the sport. It is therefore of critical importance to accurately quantify how tackle technique alters injury risk using gold-standard methodology of three-dimensional motion (3D) capture. Objective To examine the 3D motion capture methodology of rugby-style tackle techniques to provide recommendations to inform practice for future rugby code research and advance the knowledge of this field. Study Design Systematic review. Methods Articles published in English language, up to May 2020, were retrieved via nine online databases. All cross-sectional, correlational, observational, and cohort study designs using 3D motion capture of tackle techniques in rugby code players met inclusion criteria for this review. A qualitative synthesis using thematic analysis was pre-specified to identify five key themes. Results Seven articles met eligibility criteria. Participant demographic information (theme one) involved a total of 92 rugby union players, ranging in skill level and playing experience. Experimental task design information (theme two) included one-on-one, front-on (n=5) or side-on (n=1) contact between a tackler and a ball carrier, or a tackler impacting a tackle bag or bump pad (n=3). 3D data collection (theme three) reported differing sampling frequencies and marker sets. 3D data reduction and analysis (theme four) procedures could be mostly replicated, but the definitions of temporal events, joint modelling and filtering varied between studies. Findings of the studies (theme five) showed that the one-on-one tackle technique can be altered (n=5) when tackle height, leg drive and/or tackle speed is modified. A study reported tackle coaching intervention. Conclusions This is the first review to evaluate 3D motion capture of rugby-style tackle technique research. A research framework was identified: (i) participant demographic information, (ii) experimental task design information, (iii) 3D motion capture data specifications, and (iv) 3D data reduction and analysis. Adherence of future 3D tackling research to these framework principles will provide critical scientific evidence to better inform injury reduction and performance practices in the rugby codes. Trial Registration The review was registered with PROSPERO (registration number CRD42018092312)

From colonial categories to local culture: Evolving state practices of ethnic enumeration in Oceania, 1965-2014

Numerous scholars have examined how governments in particular times and places have classified their populations by ethnicity, but studies that are both cross-national and longitudinal are rare. Using a unique database of census questionnaires, we examine state practices of ethnic enumeration over a 50-year period (1965–2014) in the 24 countries and areas that comprise Oceania. The region’s extraordinary linguistic and cultural diversity, combined with its complex colonial history and indigenous politics, make it an ideal site for comparative analyses. We find a shift from biological conceptions of difference to a more cultural understanding of group identity, exemplified by a sharp rise in language questions and the decline of race-based inquiries. While local identity labels have largely displaced colonial categories, the imprimatur of previous regimes still lingers, particularly in Melanesia. These shifts in official constructions of ethnoracial differences reflect a gradual lessening of colonial influences on demographic practices

The O/OREOS Mission - Astrobiology in Low Earth Orbit

The O/OREOS (Organism/Organic Exposure to Orbital Stresses) nanosatellite is the first science demonstration spacecraft and flight mission of the NASA Astrobiology Small- Payloads Program (ASP). O/OREOS was launched successfully on November 19, 2010, to a high-inclination (72), 650-km Earth orbit aboard a US Air Force Minotaur IV rocket from Kodiak, Alaska. O/OREOS consists of 3 conjoined cubesat (each 1000 cu.cm) modules: (i) a control bus, (ii) the Space Environment Survivability of Living Organisms (SESLO) experiment, and (iii) the Space Environment Viability of Organics (SEVO) experiment. Among the innovative aspects of the O/OREOS mission are a real-time analysis of the photostability of organics and biomarkers and the collection of data on the survival and metabolic activity for micro-organisms at 3 times during the 6-month mission. We will report on the spacecraft characteristics, payload capabilities and first operational phase of the O/OREOS mission. The science and technology rationale of O/OREOS supports NASAs scientific exploration program by investigating the local space environment as well as space biology relevant to Moon and Mars missions. It also serves as precursor for experiments on small satellites, the International Space Station (ISS), future free-flyers and lunar surface exposure facilities

The O/OREOS Mission - Astrobiology in Low Earth Orbit

The O/OREOS (Organism/Organic Exposure to Orbital Stresses) nanosatellite is the first science demonstration spacecraft and flight mission of the NASA Astrobiology Small- Payloads Program (ASP). O/OREOS was launched successfully on November 19, 2010, to a high-inclination (72), 650-km Earth orbit aboard a US Air Force Minotaur IV rocket from Kodiak, Alaska. O/OREOS consists of 3 conjoined cubesat (each 1000 cu.cm) modules: (i) a control bus, (ii) the Space Environment Survivability of Living Organisms (SESLO) experiment, and (iii) the Space Environment Viability of Organics (SEVO) experiment. Among the innovative aspects of the O/OREOS mission are a real-time analysis of the photostability of organics and biomarkers and the collection of data on the survival and metabolic activity for micro-organisms at 3 times during the 6-month mission. We will report on the spacecraft characteristics, payload capabilities and first operational phase of the O/OREOS mission. The science and technology rationale of O/OREOS supports NASAs scientific exploration program by investigating the local space environment as well as space biology relevant to Moon and Mars missions. It also serves as precursor for experiments on small satellites, the International Space Station (ISS), future free-flyers and lunar surface exposure facilities

Can prior instruction successfully alter the tackle type executed by a player?

The tackle is the in-game activity with the greatest risk for injury in collision sports. Qualitative match analysis has associated injury risk with tackle technique (e.g. tackle height, head position before contact). This exploratory study used gold-standard three-dimensional (3D) motion capture to investigate whether prior instructions to a tackler to execute different torso tackle types altered their tackle technique. Fifteen amateur-level rugby code players performed four sets of 10 tackle trials after instructions from an expert coach: two Australian National Rugby League (NRL) coaching manual instructions on upper and lower torso tackle height (UpperNRL, LowerNRL); and two novel variants that altered the tackler’s contact with the ball carrier’s upper torso (UpperPop) via a vertical ‘pop action’, or mid-torso (MidTorso) via increasing the contact height to the mid-torso. 3 D motion capture confirmed a favourable ‘head up and forward’ gaze focus on ball carrier before contact and a ‘straight back’ posture was more evident in UpperPop instruction than other instructions, with the least flexion for the head, trunk, trunk-pelvis, thoracolumbar and lumbopelvic (p < 0.01). MidTorso also attained a more optimal ‘head up and forward’ and a ‘straight back’ posture than a LowerNRL (p < 0.001). ‘Leg drive on contact’ revealed ankle, hip (p < 0.01) and thigh angles (p < 0.05) differences, likely to reflect the UpperPop ‘pop action’ instruction than other instructions. For coaches, this study demonstrated that amateur-level rugby-code players could follow instruction from an expert coach to execute tackling techniques within a session. Inclusion of tackle specific coaching instruction training program may be a viable injury reduction strategy

Three-dimensional mechanics of the rugby tackle, does the ball carrier alter their movement into contact in response to the tackler’s position?

In rugby league and rugby union, the ball carrier is vulnerable to injury during a tackle. The height of the tackle has been associated with injury risk. The extent to which a ball carrier may alter their approach entering a tackle in response the tackler’s body height is unknown. This exploratory study aimed to identify if, when and how, the ball carrier modified their motion when being tackled in response to tackling instructions given to the tackler. Three-dimensional analysis was completed on 15 adult male rugby union/league players performing a front-on, one-on-one tackle at differing tackle heights. Repeated measure factorial analyses of variance were used to test for differences (P < 0.05). The ball carrier used two movement strategies: (1) increasing their stability by flexing their trunk, knee, and hips more when entering mid/high torso tackles; (2) offloading the ball or performing an evasive movement strategy by positioning themselves in a more upright body position when being tackled at a lower torso tackle height. This preliminary evidence suggests it may be beneficial for a coach to provide different instructions to the ball carrier to modify their movement strategies when being tackled in response to the height of the tackler to improve their performance and decrease their potential injury risk

Tacklers' head Inertial accelerations can be decreased by altering the way they engage in contact with ball carriers' torsos

Purpose This study aimed to investigate how four types of successfully executed, legal front-on, one-on-one torso tackles influence the tacklers' and ball carriers' inertial head kinematics. Methods A total of 455 successful front-on, one-on-one torso tackle trials completed by 15 rugby code players using three-dimensional motion capture were recorded. Tackles differed with respects to the height of the contact point on the ball carrier's torso. A series of mixed general linear models were conducted. Results The tackler sustained the highest peak resultant linear (P < 0.001) and angular (P < 0.01) head accelerations when contacting the lower torso to execute a "dominant" tackle compared with mid or upper torso, although these latter tackle types had the lowest ball carrier inertial head kinematics. When executing a "smother" tackle technique, a significant decrease in peak resultant linear head acceleration was observed with a vertical "pop" then lock action used, compared with the traditional upper torso tackling technique (P < 0.001). Conclusions Modifying the tackler's engagement with a ball carrier's torso, with respect to height and technical execution, alters the inertial head kinematics of the tackler and the ball carrier. The traditional thinking about optimal tackle technique, as instructed, may need to be reevaluated, with the midtorso being a potential alternative target contact height, whereas changes in tackle execution may be relatively protective for tacklers when executing either a dominant or smother tackle. This study provides critical scientific evidence to underpin revised coaching tackling technique interventions that might enhance player safety. Tackles in which the tackler contacts the ball carrier around the midtorso region, rather than lower torso, produce the lowest acceleration and thus may contribute to reducing head injury risk for the tackler