A Profile of Isometric Cervical Strength in Elite Professional Male Rugby Players.

OBJECTIVES: To (1) provide position-specific normative data for isometric cervical muscle strength and endurance in professional, male rugby players and (2) assess the relationship between age, height, weight, and playing position with cervical muscle strength and endurance. DESIGN: Cross-sectional study. METHODS: Professional rugby players completed peak isometric cervical strength testing followed by a test of cervical muscle endurance. Descriptive statistics for continuous variables with strength normalized to body weight were performed. Multiple linear regression was used to estimate associations between strength measurements. RESULTS: In total, 136 players participated including front-row forwards (27%), other forwards (28%), and backs (45%). Front-row forwards had significantly greater peak isometric cervical muscle strength than other position groups, with backs having the lowest strength. Extension produced the highest force for all 3 position groups (429 N ± 104 N), whereas flexion produced the least (275 N ± 65 N). Age was associated with increased isometric cervical muscle strength. There was a statistically significant relationship between peak flexion strength and flexion endurance (P = .003). The average time for the endurance tests were 55.7 (±17.1) seconds and 52.9 (±20.1) seconds for extension and flexion, respectively. Other forwards had lower cervical extension muscle endurance than backs and front-row forwards. CONCLUSIONS: Normative values for peak and endurance isometric strength in professional rugby players illustrate significant differences between playing position. Consider age, body weight, and intraindividual variability when interpreting cervical strength and endurance results. J Orthop Sports Phys Ther 2024;54(3):1-8. Epub 29 January 2024. doi:10.2519/jospt.2024.11830.

What tests and measures accurately diagnose persisting post-concussive symptoms in children, adolescents and adults following sport-related concussion? A systematic review.

OBJECTIVE: To determine what tests and measures accurately diagnose persisting post-concussive symptoms (PPCS) in children, adolescents and adults following sport-related concussion (SRC). DESIGN: A systematic literature review. DATA SOURCES: MEDLINE, Embase, PsycINFO, Cochrane Central Register of Controlled Trials, CINAHL and SPORTDiscus through March 2022. ELIGIBILITY CRITERIA: Original, empirical, peer-reviewed findings (cohort studies, case-control studies, cross-sectional studies and case series) published in English and focused on SRC. Studies needed to compare individuals with PPCS to a comparison group or their own baseline prior to concussion, on tests or measures potentially affected by concussion or associated with PPCS. RESULTS: Of 3298 records screened, 26 articles were included in the qualitative synthesis, including 1016 participants with concussion and 531 in comparison groups; 7 studies involved adults, 8 involved children and adolescents and 11 spanned both age groups. No studies focused on diagnostic accuracy. Studies were heterogeneous in participant characteristics, definitions of concussion and PPCS, timing of assessment and the tests and measures examined. Some studies found differences between individuals with PPCS and comparison groups or their own pre-injury assessments, but definitive conclusions were not possible because most studies had small convenience samples, cross-sectional designs and were rated high risk of bias. CONCLUSION: The diagnosis of PPCS continues to rely on symptom report, preferably using standardised symptom rating scales. The existing research does not indicate that any other specific tool or measure has satisfactory accuracy for clinical diagnosis. Future research drawing on prospective, longitudinal cohort studies could help inform clinical practice.

A comparison of clinical assessment with common diagnostic tools for monitoring concussion recovery in adolescent rugby union players.

OBJECTIVES: To characterise the incidence, severity and recovery of sport-related concussion (SRC) in schoolboy rugby players and explore whether the Sports Concussion Assessment Tool (SCAT), Cogstate Brief Battery (CBB) and the King-Devick test (K-D test) can be used to monitor concussion status through to full recovery. DESIGN: Prospective cohort study. SETTING: Rugby union has a high rate of SRC; however, there is little research investigating how concussion affects adolescent rugby players. PARTICIPANTS: Schoolboy rugby players. MAIN OUTCOME MEASURES: Participants completed baseline tests in the preseason. Participants diagnosed with SRC during the season attended for post-concussion testing on a weekly basis until recovered. RESULTS: 135 schoolboy rugby players (16.7 ± 0.82y) participated in the study. There were 18 SRCs in 16 participants. Concussion incidence was 9/1000 player hours. CBB and K-D tests were poorly associated with clinical assessment and produced high false negative rates (0.58 and 0.52 respectively). CONCLUSIONS: This study reports a relatively high match SRC incidence for an adolescent population. Analysis of clinical recovery with CBB and K-D test revealed a relatively poor ability to accurately monitor concussion status compared to clinical assessment suggesting that these tools should not be used in isolation for monitoring SRC recovery in adolescents.

Reliability of a neck strength test in schoolboy rugby players.

BACKGROUND: In rugby union, a bracing mechanism of the neck and trunk is normally adopted in contact situations where high linear and angular forces are produced, which may contribute to the risk for sports-related concussion (SRC). OBJECTIVES: To examine the feasibility of and test-retest reliability, both inter-rater and intra-rater reliability, of a novel neck strength test in schoolboy rugby players and to summarize neck strength values for this cohort, including rugby position-specific estimates. MATERIALS AND METHODS: 52 male schoolboy rugby union players completed the neck strength test protocol twice, eight days apart using a novel device. RESULTS: Intra-class correlation coefficients (ICCs) were good to excellent for test-retest reliability (range from 0.86 to 0.92) in all four directions. Intra-rater (ICCs range from 0.706 to 0.981) and inter-rater (ICCs range from 0.669 to 0.982) ranges were calculated. Significant differences were identified between forwards and backs for non-normalised force measures but no significant difference when normalised to bodyweight. The flexor:extensor ratio was 0.68 (SD 0.2) for forwards, 0.71 (SD 0.16) for backs and 0.67 (SD 0.16) for the cohort. DISCUSSION & CONCLUSION: While there is limited direct evidence to support a direct link between neck strength and SRC risk at present, investigating the relationship of neck strength, stiffness and impact anticipation might be a useful direction for further research. In conclusion, we describe a portable, user-friendly and safe neck strength test with good-to-excellent test-retest reliability, and intra-, inter-rater reliability. Test-retest ICC values compare favourably to gold standard fixed-frame dynamometry and are superior to hand-held dynamometry.

The use of continuous spectral analysis for the assessment of postural stability changes after sports-related concussion.

Impaired postural stability is associated with a variety of pathologies including sports-related concussion (SRC). Quantification of centre of pressure (COP) movement is the most common focus of instrumented assessment. Frequency-domain COP analyses have focused primarily on summary measures or pre-defined frequency bands but continuous analysis may provide novel and complementary insight into pathological control mechanisms. Our aims were (i) to compare post-SRC COP trajectory changes identified using clinician scores (Modified Balance Error Scoring System (M-BESS)), time-domain COP variables and continuous frequency spectral comparison; and (ii) to characterise frequency spectra changes. Male rugby players aged 15-19 years (n = 135) completed a pre-season baseline assessment comprising vision-obscured double-leg, single-leg and tandem stances on a force platform. Participants diagnosed with SRC during the season (n = 15) underwent repeat testing (median 4 days post-SRC; IQR 2.5-6.5). Baseline and post-SRC COP trajectories were compared using common time-domain COP variables, M-BESS scores and continuous frequency spectra. Post-SRC changes were identified using all three approaches. Spectral analysis revealed the largest effect size (Cliff's delta 0.39) and was the only method to identify differences in all three stances and in double-leg stance. All post-SRC increases in spectral content were in the anteroposterior direction; all decreases were in the mediolateral direction. Changes were localised to higher frequencies (1.7-8 Hz) except for double-leg stance anteroposterior direction, for which increases were observed throughout the analysed range. Our findings suggest that this method of spectral comparison may provide a more responsive and meaningful measure of postural stability changes after SRC than other commonly-used variables.

Concussion in adolescent rugby union players: comprehensive acute assessment protocol and development of the SSC concussion passport to monitor long-term health.

INTRODUCTION: Sports-related concussion (SRC) can be challenging to diagnose, assess and manage. Much of the SRC research is conducted on adults. The assessment of SRC should aim to identify deficits using a detailed multimodal assessment; however, most studies investigating the effects of SRC use diagnostic tools in isolation. It is likely that a combination of diagnostic tests will improve diagnostic accuracy. In this study, we aim to investigate how concussion affects adolescent rugby players and how a variety of diagnostic tools interact with each other as participants recover from their injury. The study will also determine the logistics of recording an individual's concussion history on a virtual 'Concussion Passport' that would remain with the individual throughout their sporting career to allow monitoring of long-term health. METHODS AND ANALYSIS: All rugby players (n=211) from the Senior Cup Teams of five schools in Dublin, Ireland will be invited to participate in the study. Baseline testing will be performed at the Sports Surgery Clinic, Dublin (SSC) before the rugby season commences. Participants will be followed up over the course of the rugby season. At baseline and at each postconcussion visit, participants will complete the following: Questionnaire, Sports Concussion Assessment Tool 3, Balance Error Scoring System, Computerised Neurocognitive Testing, Vestibulo-ocular assessment, King Devick test, Graded exercise test, Blood tests, Neck strength, FitBit. ETHICS AND DISSEMINATION: Ethical approval was obtained from the Sports Surgery Clinic Research Ethics Committee (Approval number: SSC 0020). On completion of the study, further papers will be written and published to present the results of the various tests. TRIAL REGISTRATION NUMBER: NCT03624634.