Shahid Ullah

Relationship between running loads and soft-tissue injury in elite team sport athletes

Abstract Relationship between running loads and soft-tissue injury in elite team sport athletes. J Strength Cond Res 26(4): 953–960, 2012—Although the potential link between running loads and soft-tissue injury is appealing, the evidence supporting or refuting this relationship in high-performance team sport athletes is nonexistent, with all published studies using subjective measures (e.g., ratings of perceived exertion) to quantify training loads. The purpose of this study was to investigate the risk of low-intensity (e.g., walking, jogging, total distances) and high-intensity (e.g., high acceleration and velocity efforts, repeated high-intensity exercise bouts) movement activities on lower body soft-tissue injury in elite team sport athletes. Thirty-four elite rugby league players participated in this study. Global positioning system data and the incidence of lower body soft-tissue injuries were monitored in 117 skill training sessions during the preseason and in-season periods. The frailty model (an extension of the Cox proportional regression model for recurrent events) was applied to calculate the relative risk of injury after controlling for all other training data. The risk of injury was 2.7 (95% confidence interval 1.2–6.5) times higher when very high–velocity running (i.e., sprinting) exceeded 9 m per session. Greater distances covered in mild, moderate, and maximum accelerations and low- and very low–intensity movement velocities were associated with a reduced risk of injury. These results demonstrate that greater amounts of very high–velocity running (i.e., sprinting) are associated with an increased risk of lower body soft-tissue injury, whereas distances covered at low and moderate speeds offer a protective effect against soft-tissue injury. From an injury prevention perspective, these findings provide empirical support for restricting the amount of sprinting performed in preparation for elite team sport competition. However, coaches should also consider the consequences of reducing training loads on the development of physical qualities and playing performance.

Identifying risk factors for contact injury in professional rugby league players – Application of a frailty model for recurrent injury

OBJECTIVES Well-developed physical qualities may protect against contact injuries. However, the potential contribution of physical qualities as risk or protective factors to contact injury risk is yet to be determined for rugby league. This study applied a frailty survival model that accounts for recurrent injury to identify risk factors for all physiotherapist-reported contact injury in professional rugby league players. DESIGN Prospective cohort study. METHODS Sixty-six professional rugby league players participated in this three successive year prospective study. At the start of each season, all players underwent measurements of standard anthropometry (height, body mass, and sum of seven skinfolds), speed (10 m and 40 m sprint), muscular strength (1 repetition maximum [RM] bench press, 1RM squat, 1RM weighted chin-ups), power (vertical jump, bench throw, 1RM power clean, jump squat), and endurance (maximum repetition bench press with 60 kg resistance), repeated-sprint ability (12 × 20 m sprints performed on a 20s cycle), prolonged high-intensity intermittent running ability (8 × 12 s maximal effort shuttles performed on a 48 s cycle), and maximal aerobic power (multi-stage fitness test). Data was used to demonstrate the application of the frailty model extension of the Cox proportional regression model for recurrent events to identify factors associated with a high hazard ratio (HR) of injury. RESULTS Heavier (body mass, HR=2.6, 95% CI=1.2-5.7), and faster (40 m sprint, HR=2.1, 95% CI=1.0-4.2) players, and those with poorly developed prolonged high-intensity intermittent running ability (HR=2.9, 95% CI=1.7-5.0) and upper-body strength (chin-up, HR=2.2, 95% CI=1.3-3.7) had a higher incidence of contact injuries. CONCLUSIONS This study demonstrates application of a novel statistical approach for the analysis of injury data that is recurrent in nature. This approach identified that the greater impact forces generated from heavier players with faster speed may result in an increase in recurrent contact injury rates. However, the development of prolonged high-intensity intermittent running ability and upper-body strength and power may assist to reduce the risk of contact injury in professional rugby league players.

Applications of functional data analysis: A systematic review

BackgroundFunctional data analysis (FDA) is increasingly being used to better analyze, model and predict time series data. Key aspects of FDA include the choice of smoothing technique, data reduction, adjustment for clustering, functional linear modeling and forecasting methods.MethodsA systematic review using 11 electronic databases was conducted to identify FDA application studies published in the peer-review literature during 1995–2010. Papers reporting methodological considerations only were excluded, as were non-English articles.ResultsIn total, 84 FDA application articles were identified; 75.0% of the reviewed articles have been published since 2005. Application of FDA has appeared in a large number of publications across various fields of sciences; the majority is related to biomedicine applications (21.4%). Overall, 72 studies (85.7%) provided information about the type of smoothing techniques used, with B-spline smoothing (29.8%) being the most popular. Functional principal component analysis (FPCA) for extracting information from functional data was reported in 51 (60.7%) studies. One-quarter (25.0%) of the published studies used functional linear models to describe relationships between explanatory and outcome variables and only 8.3% used FDA for forecasting time series data.ConclusionsDespite its clear benefits for analyzing time series data, full appreciation of the key features and value of FDA have been limited to date, though the applications show its relevance to many public health and biomedical problems. Wider application of FDA to all studies involving correlated measurements should allow better modeling of, and predictions from, such data in the future especially as FDA makes no a priori age and time effects assumptions.

Does the primary site of colorectal cancer impact outcomes for patients with metastatic disease

Previous reports have described differences in biology and outcome for colorectal cancer based on whether the primary is right or left sided. Further division by right, left, and rectum or even exact primary site has also been explored. Possible differences in response to biological agents have also been reported based on side of primary lesion.

Implementing an exercise-training programme to prevent lower-limb injuries: considerations for the development of a randomised controlled trial intervention delivery plan

Objective To identify important considerations for the delivery of an exercise training intervention in a randomised controlled trial to maximise subsequent participation in that randomised controlled trial and intervention uptake. Design A cross-sectional survey, with a theoretical basis derived from the Health Belief Model (HBM) and the Reach, Efficacy/Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework. Participants 374 male senior Australian Football players, aged 17–38 years. Main outcome measurements Beliefs about lower-limb injury causation/prevention, and the relative value of exercise training for performance and injury prevention. The data are interpreted within HBM constructs and implications for subsequent intervention implementation considered within the RE-AIM framework. Ordinal logistic regression compared belief scores across player characteristics. Results 74.4% of players agreed that doing specific exercises during training would reduce their risk of lower-limb injury and would be willing to undertake them. However, 64.1% agreed that training should focus more on improving game performance than injury prevention. Younger players (both in terms of age and playing experience) generally had more positive views. Players were most supportive of kicking (98.9%) and ball-handling (97.0%) skills for performance and warm-up runs and cool-downs (both 91.5%) for injury prevention. Fewer than three-quarters of all players believed that balance (69.2%), landing (71.3%) or cutting/stepping (72.8) training had injury-prevention benefits. Conclusions Delivery of future exercise training programmes for injury prevention aimed at these players should be implemented as part of routine football activities and integrated with those as standard practice, as a means of associating them with training benefits for this sport.

Prospective evaluation of the International Study Group for Liver Surgery definition of bile leak after a liver resection and the role of routine operative drainage: An international multicentre study

BACKGROUND The International Study Group for Liver Surgery (ISGLS) proposed a definition for bile leak after liver surgery. A multicentre international prospective study was designed to evaluate this definition. METHODS Data collected prospectively from 949 consecutive patients on specific datasheets from 11 international centres were collated centrally. RESULTS Bile leak occurred in 69 (7.3%) of patients, with 31 (3.3%), 32 (3.4%) and 6 (0.6%) classified as grade A, B and C, respectively. The grading system of severity correlated with the Dindo complication classification system (P < 0.001). Hospital length of stay was increased when bile leak occurred, from a median of 7 to 15 days (P < 0.001), as was intensive care stay (P < 0.001), and both correlated with increased severity grading of bile leak (P < 0.001). 96% of bile leaks occurred in patients with intra-operative drains. Drain placement did not prevent subsequent intervention in the bile leak group with a 5-15 times greater risk of intervention required in this group (P < 0.001). CONCLUSION The ISGLS definition of bile leak after liver surgery appears robust and intra-operative drain usage did not prevent the need for subsequent drain placement.

Statistical modelling for recurrent events: an application to sports injuries

Background Injuries are often recurrent, with subsequent injuries influenced by previous occurrences and hence correlation between events needs to be taken into account when analysing such data. Objective This paper compares five different survival models (Cox proportional hazards (CoxPH) model and the following generalisations to recurrent event data: Andersen-Gill (A-G), frailty, Wei-Lin-Weissfeld total time (WLW-TT) marginal, Prentice-Williams-Peterson gap time (PWP-GT) conditional models) for the analysis of recurrent injury data. Methods Empirical evaluation and comparison of different models were performed using model selection criteria and goodness-of-fit statistics. Simulation studies assessed the size and power of each model fit. Results The modelling approach is demonstrated through direct application to Australian National Rugby League recurrent injury data collected over the 2008 playing season. Of the 35 players analysed, 14 (40%) players had more than 1 injury and 47 contact injuries were sustained over 29 matches. The CoxPH model provided the poorest fit to the recurrent sports injury data. The fit was improved with the A-G and frailty models, compared to WLW-TT and PWP-GT models. Conclusions Despite little difference in model fit between the A-G and frailty models, in the interest of fewer statistical assumptions it is recommended that, where relevant, future studies involving modelling of recurrent sports injury data use the frailty model in preference to the CoxPH model or its other generalisations. The paper provides a rationale for future statistical modelling approaches for recurrent sports injury.

Statistical modelling for falls count data.

Falls and their injury outcomes have count distributions that are highly skewed toward the right with clumping at zero, posing analytical challenges. Different modelling approaches have been used in the published literature to describe falls count distributions, often without consideration of the underlying statistical and modelling assumptions. This paper compares the use of modified Poisson and negative binomial (NB) models as alternatives to Poisson (P) regression, for the analysis of fall outcome counts. Four different count-based regression models (P, NB, zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB)) were each individually fitted to four separate fall count datasets from Australia, New Zealand and United States. The finite mixtures of P and NB regression models were also compared to the standard NB model. Both analytical (F, Vuong and bootstrap tests) and graphical approaches were used to select and compare models. Simulation studies assessed the size and power of each model fit. This study confirms that falls count distributions are over-dispersed, but not dispersed due to excess zero counts or heterogeneous population. Accordingly, the P model generally provided the poorest fit to all datasets. The fit improved significantly with NB and both zero-inflated models. The fit was also improved with the NB model, compared to finite mixtures of both P and NB regression models. Although there was little difference in fit between NB and ZINB models, in the interests of parsimony it is recommended that future studies involving modelling of falls count data routinely use the NB models in preference to the P or ZINB or finite mixture distribution. The fact that these conclusions apply across four separate datasets from four different samples of older people participating in studies of different methodology, adds strength to this general guiding principle.

Ensuring implementation success: how should coach injury prevention education be improved if we want coaches to deliver safety programmes during training sessions?

Coaches play a major role in encouraging and ensuring that participants of their teams adopt appropriate safety practices. However, the extent to which the coaches undertake this role will depend upon their attitudes about injury prevention, their perceptions of what the other coaches usually do and their own beliefs about how much control they have in delivering such programmes. Fifty-one junior netball coaches were surveyed about incorporating the teaching of correct (safe) landing technique during their delivery of training sessions to junior players. Overall, >94% of coaches had strongly positive attitudes towards teaching correct landing technique and >80% had strongly positive perceptions of their own control over delivering such programmes. Coaches’ ratings of social norms relating to what others think about teaching safe landing were more positive (>94%) than those relating to what others actually do (63–74%). In conclusion, the junior coaches were generally receptive towards delivering safe landing training programmes in the training sessions they led. Future coach education could include role modelling by prominent coaches so that more community-level coaches are aware that this is a behaviour that many coaches can, and do, engage in.

The development of the lunchtime enjoyment of activity and play questionnaire

BACKGROUND Enjoyment of physical activity is as an important determinant of childrens participation in physical activity. Despite this, there is an absence of reliable measures for assessing childrens enjoyment of play activities during school lunchtime. The purpose of this study was to develop and assess the reliability of the Lunchtime Enjoyment of Activity and Play (LEAP) Questionnaire. METHODS Questionnaire items were categorized employing a social-ecological framework including intrapersonal (20 items), interpersonal (2 items), and physical environment/policy (17 items) components to identify the broader influences on childrens enjoyment. An identical questionnaire was administered on 2 occasions, 10  days apart, to 176 children aged 8-12  years, attending a government elementary school in regional Victoria, Australia. RESULTS Test-retest reliability confirmed that 35 of 39 LEAP Questionnaire items had at least moderate kappa agreement ranging from .44 to .78. Although 4 individual kappa values were low, median kappa scores for each aggregated social-ecological component reached at least moderate agreement (.44-.60). CONCLUSIONS This study confirms the LEAP Questionnaire to be a reliable, context-specific instrument with sound content, and face validity that employs a social-ecological framework to assess childrens enjoyment of school play and lunchtime activities.