Risk factors for lower leg, ankle and foot injuries during basic military training in the Maltese Armed Forces

Objectives - Basic military training is physically and psychologically demanding placing recruits at high risk of injury and premature discharge. This study aimed to identify risk factors for lower leg, ankle and foot injury in Maltese military recruits during basic training. Design - This was a prospective cohort study. Setting - An armed forces barracks. Participants - 127 recruits commencing one basic military training course agreed to participate in the study. The cohort comprised 114 males and 13 females with a mean age of 21.7 ± 2.4 years. Main outcome measures - All injuries to the lower leg, ankle and foot were recorded using the Orchard Sports Injury Classification System. Injuries were analysed for associations with fitness scores, smoking status, body mass index and foot type. Results - A total of 34 (26.2%) recruits sustained at least one injury, with 10 recruits (7.9%) terminating their training prematurely (three due to musculoskeletal injury). Smoking history, body mass index and foot type were not associated with injury risk. Lower fitness levels at the commencement of basic military training compared with fitness levels measured six months prior, were associated with higher injury risk. Conclusions - Lower fitness at the commencement of basic training was associated with higher injury risk in army recruits. Thus, conditioning programmes aimed at improving recruit fitness should be considered within an injury prevention strategy

Application of the Subsequent Injury Categorisation (SIC) model for longitudinal injury surveillance in elite rugby and cricket: Inter-sport comparisons and inter-rater reliability of coding

Background: When an athlete has more than one injury over a time period it is important to determine if these are related to each other or not. The subsequent injury categorisation (SIC) model is a method designed to consider the relationship between an index injury and subsequent injury(ies). Objective: The primary aim was to apply SIC to longitudinal injury data from two team sports: rugby union and cricket. The secondary aim was to determine SIC inter-rater reliability. Methods: Rugby union (time-loss; TL) and cricket (TL and non time-loss; NTL) injuries sustained between 2011-2014 within one international team respectively, were recorded using international consensus methods. SIC was applied by multiple raters; team clinicians, non-team clinicians, and a sports scientist. Weighted kappa and Cohen’s kappa scores were calculated for inter-rater reliability of the rugby union TL injuries and cricket NTL and TL injuries. Results: 67% and 51% of the subsequent injuries in rugby union and cricket respectively were categorised as injuries to a different body part not related to an index injury (SIC code 10). At least moderate agreement (weighted and Cohen kappa ≥ 0.60) was observed for team clinicians and the non-team clinician for both sports. Including NTL and TL injuries increased agreement between team clinician and non-team clinician, but not between clinician and sport scientist. Conclusion: The most common subsequent injury in both sports was an injury to a different body part that was not related to an index injury. The SIC model was generally reliable, with the highest agreement between clinicians working within the same team. Recommendations for future use of SIC are provided based on the proximity of the rater to the team and the raters’ level of clinical knowledge

The influence of cricket fast bowlers’ front leg technique on peak ground reaction forces

High ground reaction forces during the front foot contact phase of the bowling action are believed to be a major contributor to the high prevalence of lumbar stress fractures in fast bowlers. This study aimed to investigate the influence of front leg technique on peak ground reaction forces during the delivery stride. Three-dimensional kinematic data and ground reaction forces during the front foot contact phase were captured for 20 elite male fast bowlers. Eight kinematic parameters were determined for each performance, describing run-up speed and front leg technique, in addition to peak force and time to peak force in the vertical and horizontal directions. There were substantial variations between bowlers in both peak forces (vertical 6.7 ± 1.4 body weights; horizontal (braking) 4.5 ± 0.8 body weights) and times to peak force (vertical 0.03 ± 0.01 s; horizontal 0.03 ± 0.01 s). These differences were found to be linked to the orientation of the front leg at the instant of front foot contact. In particular, a larger plant angle and a heel strike technique were associated with lower peak forces and longer times to peak force during the front foot contact phase, which may help reduce the likelihood of lower back injuries

Does maximising ball speed in cricket fast bowling necessitate higher ground reaction forces?

This study aimed to investigate whether high peak ground reaction forces and high average loading rates are necessary to bowl fast. Kinematic and kinetic bowling data were collected for 20 elite male fast bowlers. A moderate non-significant correlation was found between ball speed and peak vertical ground reaction force with faster bowlers tending to have lower peak vertical ground reaction force (r = −0.364, P = 0.114). Faster ball speeds were correlated with both lower average vertical and lower average horizontal loading rates (r = −0.452, P = 0.046 and r = −0.484, P = 0.031, respectively). A larger horizontal (braking) impulse was associated with a faster ball speed (r = 0.574, P = 0.008) and a larger plant angle of the front leg (measured from the vertical) at front foot contact was associated with a larger horizontal impulse (r = 0.706, P = 0.001). These findings suggest that there does not necessarily need to be a trade-off between maximum ball release speed and the forces exerted on fast bowlers (peak ground reaction forces and average loading rates). Furthermore, it appears that one of the key determinants of ball speed is the horizontal impulse generated at the ground over the period from front foot contact until ball release

Relationships between fast bowling technique and ball release speed in cricket

The aim of this study was to identify the key aspects of technique that characterize the fastest bowlers. Kinematic data were collected for 20 elite male fast bowlers with 11 kinematic parameters calculated, describing elements of fast bowling technique that have previously been linked to ball release speed. Four technique variables were identified as being the best predictors of ball release speed, explaining 74% of the observed variation in ball release speed. The results indicate that the fastest bowlers have a quicker run-up and maintain a straighter knee throughout the front foot contact phase. The fastest bowlers were also observed to exhibit larger amounts of upper trunk flexion up to ball release and to delay the onset of arm circumduction. This study identifies those technique variables that best explain the differences in release speeds among fast bowlers. These results are likely to be useful in both the coaching and talent identification of fast bowlers. © 2013 Human Kinetics, Inc

RANK/RANKL/OPG pathway: genetic associations with stress fracture period prevalence in elite athletes

Context: The RANK/RANKL/OPG signalling pathway is important in the regulation of bone turnover, with single nucleotide polymorphisms (SNPs) in genes within this pathway associated with bone phenotypic adaptations. Objective: To determine whether four SNPs associated with genes in the RANK/RANKL/OPG signalling pathway were associated with stress fracture injury in elite athletes. Design, Participants, and Methods: Radiologically confirmed stress fracture history was reported in 518 elite athletes, forming the Stress Fracture Elite Athlete (SFEA) cohort. Data were analysed for the whole group, and were sub-stratified into male and cases of multiple stress fracture group. Genotypes were determined using proprietary fluorescence-based competitive allele-specific PCR assays. Results: SNPs rs3018362 (RANK) and rs1021188 (RANKL) were associated with stress fracture injury (p<0.05). 8.1% of stress fracture group and 2.8% of the non-stress fracture group were homozygote for the rare allele of rs1021188. Allele frequency, heterozygotes and homozygotes for the rare allele of rs3018362 were associated with stress fracture period prevalence (p<0.05). Analysis of the male only group showed 8.2% of rs1021188 rare allele homozygotes to have suffered a stress fracture while 2.5% of the non-stress fracture group were homozygous. In cases of multiple stress fractures, homozygotes for the rare allele of rs1021188, and individuals possessing at least one copy of the rare allele of rs4355801 (OPG) were shown to be associated with stress fracture injury (p<0.05). Conclusions: The data support an association between SNPs in the RANK/RANKL/OPG signalling pathway and the development of stress fracture injury. The association of rs3018362 (RANK) and rs1021188 (RANKL) with stress fracture injury susceptibility supports their role in the maintenance of bone health, and offers potential targets for therapeutic interventions

Sport and exercise medicine consultants are reliable in assessing tendon neovascularity using ultrasound Doppler

Objective: Several lower limb tendinopathy treatment modalities involve identification of pathological paratendinous or intratendinous neovascularisation to target proposed co-location of painful neoneuralisation. The ability to reliably locate and assess the degree of neovascularity is therefore clinically important. The Modified Ohberg Score (MOS) is frequently used to determine degree of neovascularity, but reliability has yet to be established among Sport and Exercise Medicine (SEM) consultants. This study aims to determine inter-rater and intra-rater reliability of an SEM consultant cohort when assessing neovascularity using the 5-point MOS. Method: Eleven participants (7 male and 4 female) provided 16 symptomatic Achilles and patella tendons. These were sequentially examined using power Doppler (PD) enabled ultrasound (US) imaging by 6 SEM consultants who rated neovascular changes seen using the MOS. Representative digital scan images were saved for rescoring 3 weeks later. Inter-rater and intra-rater reliability of the MOS was examined using intraclass correlation coefficient (ICC) and Kappa Agreement scores. Results: Neovascular changes were reported in 65.6% of 96 scans undertaken. ICC for inter-rater reliability was 0.86 and Fleiss Kappa 0.52. ICC for intra-rater reliability was 0.95 and Weighted Kappa 0.91. Conclusions: Neovascular changes were present in two-thirds of symptomatic tendons. Excellent SEM consultant inter-rater and intra-rater reliability was demonstrated. These findings support the use of PD-enabled US to assess neovascularity by appropriately experienced SEM consultants. Furthermore, future interventional research using a similarly experienced SEM consultant cohort can be undertaken with assurance that assessment of neovascularity will be reliable

The effect of coaching intervention on elite fast bowling technique over a two year period

Fast bowling in cricket is an activity that is well recognised as having high injury prevalence and there has been debate regarding the most effective fast bowling technique. The aim of this study was to determine whether two-year coaching interventions conducted in a group of elite young fast bowlers resulted in fast bowling technique alteration. Selected kinematics of the bowling action of 14 elite young fast bowlers were measured using an 18 camera Vicon Motion Analysis system before and after two-year coaching interventions that addressed specific elements of fast bowling technique. Mann-Whitney tests were used to determine whether any changes in kinematic variables occurred pre- and post-intervention between those who had the coaching interventions and those who didn’t. The coaching interventions, when applied, resulted in a more side-on shoulder alignment at back foot contact (BFC) (p ¼ 0.002) and decreased shoulder counter-rotation (p ¼ 0.001) however, there was no difference in the degree of change in back and front knee flexion angles or lower trunk side-flexion. This study has clearly shown that specific aspects of fast bowling technique are changeable over a two-year period in elite level fast bowlers and this may be attributed to coaching intervention

The relationship between bowling action classification and three-dimensional lower

The relationship between bowling action classification and three-dimensional lowe

Bowling loads and injury risk in male first class county cricket: Is ‘differential load’ an alternative to the acute-to-chronic workload ratio?

Objectives: Methodological concerns relating to acute-to-chronic workload ratios (ACWR) have been raised. This study aimed to assess the relationship between an alternative predictor variable named ‘differential load’, representing the smoothed week-to-week rate change in load, and injury risk in first class county cricket (FCCC) fast bowlers. Design: Prospective cohort study. Methods: Bowling loads and injuries were recorded for 49 professional male fast bowlers from six FCCC teams. A range of differential loads and ACWRs were calculated and subjected to a variable selection procedure. Results: Exponentially-weighted 7-day differential load, 9:21-day ACWR, 42-day chronic load, and 9-day acute load were the best-fitting predictor variables in their respective categories. From these, a generalized linear mixed-effects model combining 7-day differential load, 42-day chronic load, and 9-day acute load provided the best model fit. A two-standard deviation (2SD) increase in 7-day differential load (22 overs) was associated with a substantial increase in injury risk (risk ratio [RR] = 2.47, 90% CI: 1.27-4.80, most likely harmful), and a 2SD increase in 42-day chronic load (17.5 overs/week) was associated with a most likely harmful increase in injury risk (RR = 6.77, 90% CI: 2.15-21.33). For 9-day acute load, very low values (≤1 over/week) were associated with a most likely higher risk of injury versus moderate (17.5 overs/week; RR: 15.50, 90% CI: 6.19-38.79) and very high 9-day acute loads (45.5 overs/week; RR: 133.33, 90% CI: 25.26-703.81). Conclusions: Differential loads may be used to identify potentially harmful spikes in load, whilst mitigating methodological issues associated with ACWRs