key: cord-0270948-tkbj5122
authors: Hughes, R.; Cross, M.; Stokes, K.
title: A novel biomechanical injury risk score demonstrates correlation with lower limb posterior chain injury in fifty elite level rugby union athletes
date: 2021-02-03
journal: nan
DOI: 10.1101/2021.02.02.21250855
sha: dcc4e5d9c24d16bc78a674049c60a72adf6bc29b
doc_id: 270948
cord_uid: tkbj5122

Objectives: Lower limb posterior chain injury (PCI) is common amongst athletic populations, with multi-factorial risk factors including age, previous injury, strength measurements, range of motion and training load. Biomechanics are commonly considered in the prevention and rehabilitation of PCI by performance staff. However, there is no documented testing method to assess for associations between biomechanics and PCI. The aim of this study was to investigate whether there is an association between an easily applicable, novel biomechanical assessment tool and PCI. Methods: Fifty male elite-level rugby union athletes (age 22.83+/-5.08) participating in the highest tier of England were tested at the start of the 2019 pre-season period and PCIs (N=48) were recorded over the 2019/20 playing season. Participants biomechanics were analysed using two-dimensional video analysis against an Injury Risk Score (IRS) system in the performance of the combined movement - prone hip extension and knee flexion. Participants biomechanics in carrying out this movement were scored against the 10-point IRS, where the more compensatory movement recorded sees an increase in an individuals IRS. Participants IRS were then compared against the number of PCI sustained and Spearmans correlation coefficient was utilised for analysis. Results: There is a good significant association between IRS and PCI (R=0.573, p<0.001). Linear Regression demonstrated that an increase of 1 in IRS was associated with a 35% increase in PCI incidence (R2=0.346). Conclusion: A good significance between the IRS and PCI provides preliminary support for its use as an injury risk assessment tool.

The term posterior chain injury (PCI) is commonly used in relation to injuries 50 to the posterior musculoskeletal system of the lower limb. [1] [2] PCI is 51 commonly observed within athletic populations, with a reported time loss of 52 10 hours for every 1000 playing hours within elite level sport.

[3] The most 53 prevalent PCIs involve structures within the posterior musculoskeletal system 54 such as the trunk, pelvis, hamstring, and calf complexes. [4] [5] [6] [7] [8] This has 55 subsequently led to a large amount of research being conducted that focuses 56 on these areas of PCI, particularly during high velocity activities such as 57 sprinting. Sprinting requires multiple structures of the posterior 58 musculoskeletal system to work concurrently.[8-9] Occurrence of PCI is 59 attributed to a failure and a loss of concurrence somewhere within this 60 system.[9-10] Therefore, it is no surprise that PCI prevalence is high in many 61 sports that require sprinting, including rugby union, [ The most influential finding regarding modifiable risk factors relating to PCI 72 management has arguably been the introduction of the Nordic hamstring 73 4 6 complex (including the achilles tendon), hamstring muscle group, gluteal 123 muscle group, lumbar spine, and thoracic spine regions that led to time loss 124 in training and/or matches. PCI included soft tissue disruption categorised 125 using the British Athletics Muscle Injury Classification, [28] which details 126 tissue disruption of all types between grades 0-4; discopathy, neuropathy, 127 tendonopathy and overload injuries were also included. Contact injuries from 128 direct impact were excluded from the study as direct impact injuries are not 129 deemed to be affected by biomechanics. [20] Participants can score a maximum of 10 points 145 following the IRS system criteria -the more biomechanical change observed 146 from the participants anatomical prone starting position, the higher the score. 147 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted February 3, 2021.

The 5 compensatory criteria include: 1) loss of palpable co-activation in either gluteal muscle, 2) lumbar spine extension, 3) lift of the anterior superior iliac 149 spine from the plinth, 4) An increase in hip external rotation 5) An increase in 150 hip abduction. If the athlete displays a compensatory movement pattern for 151 one of the 5 criterion, 1 point would be scored per limb, left (maximum 5 152 points) and right (maximum 5 points) with a maximum of 10 points 153 achievable. 154 155 As the IRS system is novel, a repeatability pilot was performed prior to the 156 data collection and results analysed using Fleiss Kappa to assess inter-rater 157 reliability (IRR). The lead researcher educated and familiarised four 158 assessors in the IRS system. Each clinician had a minimum of five years' 159 experience in musculoskeletal medicine. The clinicians were blinded and 160 asked to analyse a small pilot group (four participants), against the IRS 161 system. Results from this pilot study were interpreted as suggested by 162 Each participant started in a prone position on a treatment plinth with arms 170 placed by their side or above their head (as in figure 1 ) to negate the use of 171 upper limb stabilisation during testing. The testing clinician then placed their 172 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted February 3, 2021. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted February 3, 2021.

Participants were first involved in research during the first day of data 247 collection when informed consent was obtained, and their IRS was recorded. 248

The research question and outcome measures were developed by the 249 authors, and participants were informed of these using a patient information 250 sheet prior to data collection. Participants were not involved in study design, 251 recruitment or conduction and they were not asked to assess the burden or 252 time required to participate in the study. In the dissemination of the results 253 the participants will receive their individual IRS followed by a discussion 254 around their PCI risk with advice around reducing this risk. 255

Fifty subjects participated in the study (age 22.83±5.08). The mean IRS 257 score across the population was 5.80±1.74 and participants IRS ranged from CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted February 3, 2021. ; https://doi.org/10.1101/2021.02.02.21250855 doi: medRxiv preprint The results demonstrate good significant correlation between the novel IRS 345 system compared to PCI within in an athletic population. This study adds 346 evidence that demonstrates that an increased IRS has influence on an 347 individual's PCI risk and provides guidance for a uniformed assessment tool 348 in assessing this risk. Establishing individual injury risk scores for athletes in 349 this way may aid in preventing and managing PCI that lead to time loss in 350 training and matches. The IRS system can be utilised easily within 351 musculoskeletal settings requiring minimal equipment, making it easily 352 applicable around the constraints of performance-medical environments. 353 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted February 3, 2021. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted February 3, 2021. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted February 3, 2021. ; Images Available upon reasonable request from author. Blanked to maintain anonymity.

. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted February 3, 2021. ; https://doi.org/10.1101/2021.02.02.21250855 doi: medRxiv preprint . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted February 3, 2021. ; https://doi.org/10.1101/2021.02.02.21250855 doi: medRxiv preprint . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted February 3, 2021. ; https://doi.org/10.1101/2021.02.02.21250855 doi: medRxiv preprint

Hamstring strain injuries: 381 are we heading in the right direction?

Proximal 385 neuromuscular control protects against hamstring injury in male 386 football players: a prospective study with EMG time-series analysis 387 during maximal sprinting

Injury-prevention priorities according to 391 playing position in professional rugby union players

Acute hamstring injuries in 395

Swedish elite football: a prospective randomised controlled clinical trial 396 comparing two rehabilitation protocols

Is There a Pathological Gait 400

Human hamstring muscles adapt 477 to eccentric exercise by changing optimum length

Preventive Effect of Eccentric Training on Acute Hamstring Injuries in 482

Men's Soccer A Cluster-Randomized Controlled Trial

Hamstring injuries: prevention and treatment-an update

Training-induced changes in anterior pelvic tilt: potential implications 490 for hamstring strain injuries management

Prone Hip Extension 494

Muscle Recruitment is Associated with Hamstring Injury Risk in 495

British athletics muscle injury 499 classification: a new grading system