Wayne Viljoen

The reliability of the FitroDyne as a measure of muscle power.

The FitroDyne is a device that attaches to conventional resistance-training equipment to measure speed of movement, from which muscle power is calculated. The aim of this study was to quantify the repeatability of the measurement of muscle power with the FitroDyne during squat jump and biceps curl exercises. Thirty male subjects completed 3 trials, each consisting of 6 squat jumps and 6 biceps curls of increasing loads. Upper body and lower body maximum power was predicted from the force-velocity curves derived from the range of weights used for each trial. Maximum power measurements of a squat jump (range, 911–1,673 W) and biceps curl (range, 45–110 W) had intraclass correlation coefficients (ICC) of R = 0.97 (95% CI, 0.95–0.98) and R = 0.97 (95% CI, 0.95–0.98), respectively. The limits of agreement for the squat jump and biceps curl trials were 217 ± 96 W and 0.11 ± 13.90 W, respectively. It may be concluded that muscle power can be measured with a high degree of reliability with the FitroDyne. The limits of agreement need to be considered when data are interpreted.

BokSmart - implementing a National Rugby Safety Programme.

The BokSmart National Rugby Safety Programme is a joint initiative between the South African Rugby Union and the Chris Burger/Petro Jackson Players Fund aimed at implementing evidence-based sports medicine and exercise research to prevent injury and enhance performance at all levels of rugby union in South Africa. The BokSmart programme has four main elements: Head and neck trauma form a large part of the injuries associated with contact and collision sport.6 Rugby Union is a collision sport that exposes players to cervical spinal injuries, with permanent disabling injuries being the most serious and highly publicised complication.7 Part of BokSmart s mandate is to record serious and catastrophic head, neck and spine rugby injuries in South Africa (SA), and to formulate appropriate initiatives aimed at prevention of these injuries.4 Even though spinal cord injuries in rugby union are few, there are inherent risks associated primarily with the tackle and scrum6 that are the main contributors to spinal injuries, with scrum injuries consistently being more severe.3,–,5 7 10 Over the last 4 years in SA, these phases contributed to 78% of all serious and catastrophic head, neck and spine injuries in …

The incidence of rugby-related catastrophic injuries (including cardiac events) in South Africa from 2008 to 2011: a cohort study

Objectives To establish an accurate and comprehensive injury incidence registry of all rugby union-related catastrophic events in South Africa between 2008 and 2011. An additional aim was to investigate correlates associated with these injuries. Design Prospective. Setting The South African amateur and professional rugby-playing population. Participants An estimated 529 483 Junior and 121 663 Senior rugby union (‘rugby’) players (population at risk). Outcome measures Annual average incidences of rugby-related catastrophic injuries by type (cardiac events, traumatic brain and acute spinal cord injuries (ASCIs)) and outcome (full recoveries—fatalities). Playing level (junior and senior levels), position and event (phase of play) were also assessed. Results The average annual incidence of ASCIs and Traumatic Brain Injuries combined was 2.00 per 100 000 players (95% CI 0.91 to 3.08) from 2008 to 2011. The incidence of ASCIs with permanent outcomes was significantly higher at the Senior level (4.52 per 100 000 players, 95% CI 0.74 to 8.30) than the Junior level (0.24 per 100 000 players, 95% CI 0 to 0.65) during this period. The hooker position was associated with 46% (n=12 of 26) of all permanent ASCI outcomes, the majority of which (83%) occurred during the scrum phase of play. Conclusions The incidence of rugby-related catastrophic injuries in South Africa between 2008 and 2011 is comparable to that of other countries and to most other collision sports. The higher incidence rate of permanent ASCIs at the Senior level could be related to the different law variations or characteristics (eg, less regular training) compared with the Junior level. The hooker and scrum were associated with high proportions of permanent ASCIs. The BokSmart injury prevention programme should focus efforts on these areas (Senior level, hooker and scrum) and use this study as a reference point for the evaluation of the effectiveness of the programme.

Tackle technique and tackle-related injuries in high-level South African Rugby Union under-18 players: real-match video analysis

Background The high injury rate associated with rugby union is primarily due to the tackle, and poor contact technique has been identified as a risk factor for injury. We aimed to determine whether the tackle technique proficiency scores were different in injurious tackles versus tackles that did not result in injury using real-match scenarios in high-level youth rugby union. Methods Injury surveillance was conducted at the under-18 Craven Week tournaments (2011–2013). Tackle-related injury information was used to identify injury events in the match video footage and non-injury events were identified for the injured player cohort. Injury and non-injury events were scored for technique proficiency and Cohens effect sizes were calculated and the Student t test (p<0.05) was performed to compare injury versus non-injury scores. Results The overall mean score for front-on ball-carrier proficiency was 7.17±1.90 and 9.02±2.15 for injury and non-injury tackle events, respectively (effect size=moderate; p<0.05). The overall mean score for side/behind ball-carrier proficiency was 4.09±2.12 and 7.68±1.72 for injury and non-injury tackle events, respectively (effect size=large; p<0.01). The overall mean score for front-on tackler proficiency was 7.00±1.95 and 9.35±2.56 for injury and non-injury tackle events, respectively (effect size=moderate; p<0.05). The overall mean score for side/behind tackler proficiency was 5.47±1.60 and 8.14±1.75 for injury and non-injury tackle events, respectively (effect size=large; p<0.01). Summary Higher overall mean and criterion-specific tackle-related technique scores were associated with a non-injury outcome. The ability to perform well during tackle events may decrease the risk of injury and may manifest in superior performance.

Contact technique and concussions in the South African under-18 Coca-Cola Craven Week Rugby tournament

Abstract In rugby union, understanding the techniques and events leading to concussions is important because of the nature of the injury and the severity and potential long-term consequences, particularly in junior players. Proper contact technique is a prerequisite for successful participation in rugby and is a major factor associated with injury. However, the execution of proper contact technique and its relationship to injury has yet to be studied in matches. Therefore, the aim of this study was to compare contact techniques leading to concussion with a representative sample of similarly matched non-injury (NI) contact events. Injury surveillance was conducted at the 2011–2013 under-18 Craven Week Rugby tournaments. Video footage of 10 concussive events (5 tackle, 4 ruck and 1 aerial collision) and 83 NI events were identified (19 tackle, 61 ruck and 3 aerial collisions). Thereafter, each phase of play was analysed using standardised technical proficiency criteria. Overall score for ruck proficiency in concussive events was 5.67 (out of a total of 15) vs. 6.98 for NI events (n = 54) (effect size = 0.52, small). Overall average score for tackler proficiency was 7.25 (n = 4) and 6.67 (n = 15) for injury and NI tackles, respectively (out of 16) (effect size = 0.19, trivial). This is the first study to compare concussion injury contact technique to a player-matched sample of NI contact techniques. Certain individual technical criteria had an effect towards an NI outcome, and others had an effect towards a concussive event, highlighting that failure to execute certain techniques may substantially increase the opportunity for concussion.

Tackle-related injury rates and nature of injuries in South African Youth Week tournament rugby union players (under-13 to under-18): an observational cohort study

Objectives The tackle situation is most often associated with the high injury rates in rugby union. Tackle injury epidemiology in rugby union has previously been focused on senior cohorts but less is known about younger cohorts. The aim of this study was to report on the nature and rates of tackle-related injuries in South African youth rugby union players representing their provinces at national tournaments. Design Observational cohort study. Setting Four South African Youth Week tournaments (under-13 Craven Week, under-16 Grant Khomo Week, under-18 Academy Week, under-18 Craven Week). Participants Injury data were collected from 3652 youth rugby union players (population at risk) in 2011 and 2012. Outcome measures Tackle-related injury severity (‘time-loss’ and ‘medical attention’), type and location, injury rate per 1000 h (including 95% CIs). Injury rate ratios (IRR) were calculated and modelled using a Poisson regression. A χ2 analysis was used to detect linear trends between injuries and increasing match quarters. Results The 2012 under-13 Craven Week had a significantly greater ‘time-loss’ injury rate when compared with the 2012 under-18 Academy Week (IRR=4.43; 95% CI 2.13 to 9.21, p<0.05) and under-18 Craven Week (IRR=3.52; 95% CI 1.54 to 8.00, p<0.05). The Poisson regression also revealed a higher probability of ‘overall’ (‘time-loss’ and ‘medical attention’ combined) and ‘time-loss’ tackle-related injuries occurring at the under-13 Craven Week. The proportion of ‘overall’ and ‘time-loss’ injuries increased significantly with each quarter of the match when all four tournaments were combined (p<0.05). Conclusions There was a difference in the tackle-related injury rate between the under-13 tournament and the two under-18 tournaments, and the tackle-related injury rate was higher in the final quarter of matches. Ongoing injury surveillance is required to better interpret these findings. Injury prevention strategies targeting the tackle may only be effective once the rate and nature of injuries have been accurately determined.

An evidence-driven approach to scrum law modifications in amateur rugby played in South Africa

Background In 2012, the South African Rugby Union (SARU) approved a new set of scrum laws for amateur rugby played in the country, to be implemented at the start of the 2013 rugby season. These law changes were primarily based on the relatively high proportion of scrum-related catastrophic injury data collected as part of the BokSmart National Rugby Safety Programme (BokSmart) over the preceding 4 years (2008–2011). Aim To describe the scrum-related catastrophic injury data in South Africa over the past 5 years (2008–2012), and to discuss how this evidence justifies the change in the Amateur Scrum Laws to make this aspect of the game safer in South Africa. Methods Catastrophic injury data were collected through BokSmart at amateur and professional levels, during training and matches over 5 years (2008–2012). Results The scrum phase accounted for 33% (n=20 of 60) of all catastrophic injuries between 2008 and 2012. Eighteen of the 20 scrum injuries (90%) were confirmed as acute spinal cord injuries, with 13 of these being permanent injuries. For the scrum injury mechanisms that were provided (n=19), ‘impact on the engagement’ was the most frequently reported (n=11 of 19, 58%), followed by ‘collapsed scrum’ (n=7 of 19, 37%) and ‘popping out’ (n=1 of 19, 5%). Conclusions Based on these scrum-related catastrophic injury data, a change in the Amateur Scrum Laws of South African Rugby was justified. The main purpose of these scrum law changes is to reduce the number of scrum-related catastrophic injuries in the country, by minimising the opportunity for impact injury and subsequent scrum collapse in amateur rugby in South Africa, thereby making this aspect of the game of rugby safer.

Characteristics of an ‘effective’ tackle outcome in Six Nations rugby

Abstract Rugby is a full contact sport that frequently comprises of tackle situations between two or more players. At present there is no research available that has quantified the defining elements that lead to ‘effective’ tackle outcomes in matches or whether they factor in the success or failure of teams. The purpose of this study was to understand the actions of the tackler during contact with the ball-carrier and relate them to the ‘effectiveness’ of the tackle outcome, during rugby match play. Matches (n=15) from the 2007 Six Nations Tournament were analysed. ‘Effective’ tackling was assessed with regards to the territorial change of the ball-carrier from the point of contact with the tackler to completion of the tackle, and characterised in terms of the tacklers body position, the angle at which the tackler approached the tackle and the outcome. The ‘less effective’ tackle is 34% more prevalent (P<0.001) than the ‘effective’ tackle during match play. Winning teams were involved in fewer tackle situations and made 3% more ‘effective’ tackles and 4% fewer ‘less effective’ tackles than losing teams. ‘Effective’ tackle outcomes were found to have a greater percentage of the players torso leaning forward and oblique angle approaches to the ball-carrier. The difference in the frequency of upright and back foot characteristics differentiated winning from losing teams. This was the first study to describe the characteristics of an ‘effective’ tackle outcome and serves as a basis from which further research can be done on the tackle situation.

Mechanisms and Factors Associated With Tackle-Related Injuries in South African Youth Rugby Union Players:

Background: The majority of injuries in rugby union occur during tackle events. The mechanisms and causes of these injuries are well established in senior rugby union. Purpose: To use information from an injury database and assess video footage of tackle-related injuries in youth rugby union matches to identify environmental factors and mechanisms that are potentially confounding to these injuries. Study Design: Descriptive epidemiological study. Methods: Injury surveillance was conducted at the under-18 Craven Week rugby tournament. Tackle-related injury information was used to identify injury events in match video footage (role-matched noninjury tackle events were identified for the cohort of injured players). Events were coded using match situational variables (precontact, contact, and postcontact). Relative risk ratio (RRR; ratio of probability of an injury or noninjury outcome occurring when a characteristic was observed) was reported by use of logistic regression. Results: In comparison with the first quarter, injury risk was greater in the third (RRR = 9.75 [95% CI, 1.71-55.64]; P = .010) and fourth quarters (RRR = 6.97 [95% CI, 1.09-44.57]; P = .040) for ball carriers and in the fourth quarter (RRR = 9.63 [95% CI, 1.94-47.79]; P = .006) for tacklers. Ball carriers were less likely to be injured when they were aware of impending contact (RRR = 0.14 [95% CI, 0.03-0.66]; P = .012) or when they executed a moderate fend (hand-off) (RRR = 0.22 [95% CI, 0.06-0.84]; P = .026). Tacklers were less likely to be injured when performing shoulder tackles (same side as leading leg) in comparison to an arm-only tackle (RRR = 0.02 [95% CI, 0.001-0.79]; P = .037). Ball carriers (RRR = 0.09 [95% CI, 0.01-0.89]; P = .040) and tacklers (RRR = 0.02 [95% CI, 0.001-0.32]; P =.006) were less likely to be injured when initial contact was made with the tackler’s shoulder/arm instead of his head/neck. Conclusion: The relative risk of tackle-related injury was higher toward the end of matches. Incorrect technique may contribute to increased injury risk. Implementing recovery strategies between matches, training safe and effective techniques, and improving levels of conditioning may counter the negative effects of fatigue. These findings may assist stakeholders in youth rugby to formulate injury prevention strategies and may improve the preparation of field-side medical staff for managing tackle-related injuries at these or similar tournaments.

Incidence and Factors Associated With Concussion Injuries at the 2011 to 2014 South African Rugby Union Youth Week Tournaments.

Objective:To determine the concussion incidence and to identify factors associated with concussion in South African youth rugby union players. Design:Prospective cohort study. Setting:Injury surveillance was completed at the South African Rugby Union Youth Week tournaments (under-13, under-16, and under-18 age groups). Participants:South African youth rugby union players. A total of 7216 players participated in 531 matches between 2011 and 2014. Interventions:None. Main Outcome Measures:Concussion incidence was calculated per 1000 player-match-hours with 95% CIs. Poisson regression was used to calculate the incidence rate ratio (IRR) between factors (age, time period, playing position, and activity at the time of concussion) potentially associated with concussions. Results:The concussion incidence was 6.8/1000 player-match-hours (95% CI, 5.5-8.1) across all age groups. Under-13s (IRR, 1.5; P = 0.09) and under-16s (IRR, 1.7; P = 0.03) had higher concussion incidence rates than the under-18 age group. The incidence was higher in the third (IRR, 2.1; P = 0.04) and fourth (IRR, 2.5; P = 0.01) quarters of matches compared with the first quarter. Sixty-two percent of concussions occurred in the tackle situation. The tackler had a 4-fold greater concussion rate (IRR, 4.3; P < 0.001) compared with the ball carrier. The hooker and loose forwards had higher incidence rates than several other player positions (P < 0.05). Conclusions:The reported concussion incidence falls within the broad range previously reported in youth rugby. The evidence highlighted in this study may contribute to targeted concussion prevention strategies and provide a baseline against which the effectiveness of future interventions can be measured.