Incidence, prevalence and risk factors for low back pain in adolescent athletes: a systematic review and meta-analysis.

OBJECTIVE: To investigate the incidence, prevalence, risk factors and morphological presentations of low back pain (LBP) in adolescent athletes. DESIGN: Systematic review with meta-analysis. DATA SOURCES: Medline, Embase, CINAHL via EBSCO, Web of Science, Scopus. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies evaluating the incidence and/or prevalence of LBP in adolescent athletes across all sports. RESULTS: There were 80 studies included. The pooled incidence estimate of LBP in adolescent athletes was 11% (95% CI 8% to 13%, I2=0%) for 2 years, 36.0% (95% CI 4% to 68%, I2=99.3%) for 12 months and 14% (95% CI 7% to 22%, I2=76%) for 6 months incidence estimates. The pooled prevalence estimate of LBP in adolescent athletes was 42% (95% CI 29% to 55%, I2=96.6%) for last 12 months, 46% (95% CI 41.0% to 52%, I2=56%) for last 3 months and 16% (95% CI 9% to 23%, I2=98.3%) for point prevalence. Potential risk factors were sport participation, sport volume/intensity, concurrent lower extremity pain, overweight/high body mass index, older adolescent age, female sex and family history of LBP. The most common morphology reported was spondylolysis. Methodological quality was deemed high in 73% of cross-sectional studies and in 30% of cohort studies. Common reasons for downgrading at quality assessment were use of non-validated survey instruments and imprecision or absence of LBP definition. SUMMARY/CONCLUSION: LBP is common among adolescent athletes, although incidence and prevalence vary considerably due to differences in study methodology, definitions of LBP and data collection. PROSPERO REGISTRATION NUMBER: CRD42020157206.

Custom-Fitted Compression Garments Enhance Recovery From Muscle Damage in Rugby Players.

ABSTRACT: Brown, F, Jeffries, O, Gissane, C, Howatson, G, van Someren, K, Pedlar, C, Myers, T, and Hill, JA. Custom-fitted compression garments enhance recovery from muscle damage in rugby players. J Strength Cond Res 36(1): 212-219, 2022-to evaluate the effects of custom-fitted compression garments (CG) on recovery from muscle damage in rugby players. Forty-five players were tested for lower-body strength, power, and indices of muscle damage before completing a damaging protocol (20 × 20-m sprints with 5-m deceleration, 100 drop jumps). Players were randomly assigned to wear either custom-fitted (CF, n = 13), or standard-sized CG (SSG, n = 16), or to receive sham ultrasound therapy (CON, n = 16) immediately after exercise. Players were retested immediately, then after 24 and 48 hours. Strength recovery was significantly different between groups (F = 2.7, p = 0.02), with only CF recovering to baseline values by 48 hours (p = 0.973). Time × condition effects were also apparent for creatine kinase activity (χ2 = 30.4, p < 0.001) and midthigh girth (F = 3.7, p = 0.005), with faster recovery apparent in CF compared with both CON and SSG (p < 0.05). Custom-fitted CG improved strength recovery and indices of muscle damage in rugby players, compared with controls and standard-sized garments. Athletes and coaches would be advised to use appropriately fitted CG to enhance strength recovery after damaging exercise.

Annual Baseline King-Devick Oculomotor Function Testing Is Needed Due to Scores Varying by Age.

OBJECTIVE: To document baseline King-Devick (K-D) oculomotor function scores for male and female participants aged between 4 and 20 years old. METHODS: Utilising a cross section of schools, rugby clubs and gymnastic clubs, 1936 participants (1300 male, 636 female) completed the spiral-bound K-D test for the identification of disturbed oculomotor function. RESULTS: This study identified that overall, the baseline scores of the K-D test became faster by 1.4 (0.3 to 4.5) s per year, when compared with the previous age group in the same number of reading card groups. When comparing normative values of the original K-D validation study with the same age groups of the current cohort, participants aged 6 to 11 years recorded a faster baseline time (range 3.5 to 8.6 s), while those in the 12 to 14 years. age group recorded slower baseline times (range -3.9 to -7.9 s). DISCUSSION: In general, there were age group differences, but not sex differences, for K-D test times in the current cohort. Analysis of single card times, across all age groups, showed changes likely due to improved reading time. CONCLUSION: The results support the need for individualised annual pre-injury baseline testing of the K-D test.

2021 consensus statement for preventing and managing low back pain in elite and subelite adult rowers.

PURPOSE: To synthesise evidence on low back pain (LBP) in adult rowers and to create a consensus statement to inform clinical practice. METHODS: There were four synthesis steps that informed the consensus statement. In step one, seven expert clinicians and researchers established the scope of the consensus statement and conducted a survey of experienced and expert clinicians to explore current practice. In step two, working groups examined current evidence relating to key scope questions and summarised key issues. In step three, we synthesised evidence for each group and used a modified Delphi process to aid in the creation of the overall consensus statements. Finally, in step four, we combined information from step three with the findings of the clinician survey (and with athlete and coach input) to produce recommendations for clinical practice. RESULTS: The scope of the consensus statement included epidemiology; biomechanics; management; the athlete's voice and clinical expertise. Prevention and management of LBP in rowers should include education on risk factors, rowing biomechanics and training load. If treatment is needed, non-invasive management, including early unloading from aggravating activities, effective pain control and exercise therapy should be considered. Fitness should be maintained with load management and progression to full training and competition. The role of surgery is unclear. Management should be athlete focused and a culture of openness within the team encouraged. CONCLUSION: Recommendations are based on current evidence and consensus and aligned with international LBP guidelines in non-athletic populations, but with advice aimed specifically at rowers. We recommend that research in relation to all aspects of prevention and management of LBP in rowers be intensified.

Treating low back pain in athletes: a systematic review with meta-analysis.

OBJECTIVE: To summarise the evidence for non-pharmacological management of low back pain (LBP) in athletes, a common problem in sport that can negatively impact performance and contribute to early retirement. DATA SOURCES: Five databases (EMBASE, Medline, CINAHL, Web of Science, Scopus) were searched from inception to September 2020. The main outcomes of interest were pain, disability and return to sport (RTS). RESULTS: Among 1629 references, 14 randomised controlled trials (RCTs) involving 541 athletes were included. The trials had biases across multiple domains including performance, attrition and reporting. Treatments included exercise, biomechanical modifications and manual therapy. There were no trials evaluating the efficacy of surgery or injections. Exercise was the most frequently investigated treatment; no RTS data were reported for any exercise intervention. There was a reduction in pain and disability reported after all treatments. CONCLUSIONS: While several treatments for LBP in athletes improved pain and function, it was unclear what the most effective treatments were, and for whom. Exercise approaches generally reduced pain and improved function in athletes with LBP, but the effect on RTS is unknown. No conclusions regarding the value of manual therapy (massage, spinal manipulation) or biomechanical modifications alone could be drawn because of insufficient evidence. High-quality RCTs are urgently needed to determine the effect of commonly used interventions in treating LBP in athletes.

Prevalence and risk factors for back pain in sports: a systematic review with meta-analysis.

OBJECTIVES: We aimed to determine the prevalence of low back pain (LBP) in sport, and what risk factors were associated with LBP in athletes. DESIGN: Systematic review with meta-analysis. DATA SOURCES: Literature searches from database inception to June 2019 in Medline, Embase, Cumulated Index to Nursing and Allied Health Literature (CINAHL), Web of Science and Scopus, supplemented by grey literature searching. ELIGIBILITY CRITERIA: Studies evaluating prevalence of LBP in adult athletes across all sports. RESULTS: Eighty-six studies were included (30 732, range 20-5958, participants), of which 45 were of 'high' quality. Definitions of LBP varied widely, and in 17 studies, no definition was provided. High-quality studies were pooled and the mean point prevalence across six studies was 42%; range 18%-80% (95% CI 27% to 58%, I2=97%). Lifetime prevalence across 13 studies was 63%; range 36%-88% (95% CI 51% to 74%, I2=99%). Twelve-month LBP prevalence from 22 studies was 51%; range 12%-94% (95% CI 41% to 61%, I2=98%). Comparison across sports was limited by participant numbers, study quality and methodologies, and varying LBP definitions. Risk factors for LBP included history of a previous episode with a pooled OR of 3.5; range 1.6-4.0 (95% CI 1.9 to 6.4). Statistically significant associations were reported for high training volume, periods of load increase and years of exposure to the sport. CONCLUSION: LBP in sport is common but estimates vary. Current evidence is insufficient to identify which sports are at highest risk. A previous episode of LBP, high training volume, periods of load increase and years of exposure are common risk factors.

Low Dose Resistance Exercise: A Pilot Study Examining Effects on Blood Pressure and Augmentation Index Between Intensities.

INTRODUCTION: The effects of resistance exercise on vascular function are unclear. AIM: To investigate the acute haemodynamic (blood pressure and augmentation index) and rate of perceived exertion (RPE) response to two types of resistance exercises of equal workload-a set of unilateral 35% of one repetition maximum (1RM) quadriceps extension and a set of unilateral 70% 1RM quadriceps extension. METHODS: Twenty two young healthy males completed both exercises on separate days. Heart rate, central and peripheral systolic and diastolic blood pressure (BP), augmentation pressure, augmentation index (AIx), augmentation index at a heart rate of 75 beats per minute (AIx75), and RPE were measured using applanation tonometry before exercise, immediately after exercise, 5 min after exercise and 15 min after exercise. RESULTS: AIx75 was significantly lower 5 min after exercising at 35% of 1RM than 70% of 1RM. Systolic blood pressure was significantly lower at 5 min post exercise for both intensities. There was no significant difference in RPE between conditions or time points. CONCLUSIONS: Results suggest that changes in blood pressure and augmentation index vary depending on the intensity of resistance exercise regardless of the volume of exercise carried out. Changes in AIx75 in response to resistance exercise may be independent of changes in BP.

Vascular and Parenchymal Enhancement Assessment by Dual-Phase Dual-Energy CT in the Diagnostic Investigation of Pulmonary Hypertension.

PURPOSE: To evaluate pulmonary hypertension (PH) determination by dual-phase dual-energy CT pulmonary angiography vascular enhancement and perfused blood volume (PBV) quantification. MATERIALS AND METHODS: In this prospective study, consecutive participants who underwent both right heart catheterization and dual-phase dual-energy CT pulmonary angiography were included between 2012 and 2014. CT evaluation comprised a standard pulmonary arterial phase dual-energy CT pulmonary angiography acquisition (termed series 1) followed 7 seconds after series 1 completion by a second dual-energy CT pulmonary angiography acquisition limited to the central 10 cm of the pulmonary vasculature (termed series 2). In both series, enhancement in the main pulmonary artery (PAenh), the descending aorta (DAenh), and whole-lung PBV (WLenh) was calculated from dual-energy CT pulmonary angiography iodine images. Dual-energy CT pulmonary angiography and standard cardiovascular metrics were correlated to mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) with additional receiver operating characteristic curve analysis. RESULTS: A total of 102 participants (median age, 70; range, 58-78 years; 60 women) were included. Sixty-five participants had PH defined by mPAP of greater than or equal to 25 mm Hg, and 51 participants had PH defined by PVR of greater than 3 Wood units. By either definition, participants with PH had higher PAenh/WLenh ratio and lower WLenh and DAenh in series 1 (P < .05) and higher PAenh and WLenh in series 2 (P < .05). Change in WLenh determined highest diagnostic accuracy to define disease by mPAP (area under the receiver operating characteristic curve [AUC], 0.78) and PVR (AUC, 0.79) and the best mPAP correlation (r = 0.62). PAenh series 2 correlated best with PVR (r = 0.49). Multiple linear regression analysis incorporating WLenh and series 1 DAenh improved PVR correlation (r = 0.56). Combining these dual-energy CT pulmonary angiography metrics with main pulmonary artery size and right-to-left ventricular ratio achieved the highest correlations (mPAP, r = 0.71; PVR, r = 0.64). CONCLUSION: Dual-phase dual-energy CT pulmonary angiography enhancement quantification appears to improve mPAP and PVR prediction in noninvasive PH evaluation.Supplemental material is available for this article.See also the commentary by Kay in this issue.© RSNA, 2020.

Identification of dropout predictors to a community-based physical activity programme that uses motivational interviewing.

BACKGROUND: Participant dropout reduces intervention effectiveness. Predicting dropout has been investigated for Exercise Referral Schemes, but not physical activity (PA) interventions with Motivational Interviewing (MI). METHODS: Data from attendees (n = 619) to a community-based PA programme utilizing MI techniques were analysed using a chi-squared test to determine dropout and attendance group differences. Binary logistic regression investigated the likelihood of dropout before 12 weeks. RESULTS: A total of 44.7% of participants dropped out, with statistical (P < 0.05) differences between groups for age, PA and disability. Regression for each variable showed participants aged 61-70 years (OR = 0.28, CI = 0.09-0.79; P = 0.018), >70 years (OR = 0.30, CI = 0.09-0.90; P = 0.036), and high PA (OR = 0.40, CI = 0.20-0.75; P = 0.006) reduced dropout likelihood. Endocrine system disorders (OR = 4.24, CI = 1.19-19.43; P = 0.036) and musculoskeletal disorders (OR = 3.14, CI = 1.84-5.45; P < 0.001) increased dropout likelihood. Significant variables were combined in a single regression model. Dropout significantly reduced for 61-70 years old (OR = 0.31, CI = 0.10-0.90; P = 0.035), and high PA (OR = 0.39, CI = 0.19-0.76; P = 0.008). Musculoskeletal disorders increased dropout (OR = 2.67, CI = 1.53-4.75; P < 0.001). CONCLUSIONS: Age, PA and disability type significantly influence dropout at 12 weeks. These are the first results specific to MI based programmes indicating the inclusion of MI and highlighting the need for further research.

Association between eccentric knee flexor strength and hamstring injury risk in 185 elite Gaelic football players.

Hamstring strains are the most common time-loss injury in elite Gaelic football affecting over 20% of players per season. Thus, there is a need to identify factors contributing to the onset of hamstring injuries in order to inform injury risk management strategies. The current study investigated whether eccentric knee flexor strength and between-limb imbalances were associated with increased risk of sustaining a time-loss hamstring injury in elite Gaelic football players. A total of 185 elite male players (26.9 ± 2.7 years, 86.4 ± 6.2 kg, 183.4 ± 5.6) were prospectively followed for 12 weeks from the day of testing. Injury data were provided by the team medical staff. Twenty-eight players (16%) sustained a time-loss hamstring injury following testing. Players that did not sustain a hamstring injury had greater average between-limb asymmetries (uninjured = 9.1%, 95% CI 7.8-10.1; injured = 5.1%, 95% CI 3.7-6.7; P = .001). Eccentric knee flexor strength profiles were not associated with increased or decreased risk of sustaining a hamstring injury and did not alter the post-test probability of sustaining a hamstring injury across the investigation period. These findings do not support the use of eccentric knee flexor strength metrics in managing hamstring injury risk in elite male Gaelic football players.

Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial.

BACKGROUND: We implemented a blood flow restriction resistance training (BFR-RT) intervention during an 8-week rehabilitation programme in anterior cruciate ligament reconstruction (ACLR) patients within a National Health Service setting. OBJECTIVE: To compare the effectiveness of BFR-RT and standard-care traditional heavy-load resistance training (HL-RT) at improving skeletal muscle hypertrophy and strength, physical function, pain and effusion in ACLR patients following surgery. METHODS: 28 patients scheduled for unilateral ACLR surgery with hamstring autograft were recruited for this parallel-group, two-arm, single-assessor blinded, randomised clinical trial following appropriate power analysis. Following surgery, a criteria-driven approach to rehabilitation was utilised and participants were block randomised to either HL-RT at 70% repetition maximum (1RM) (n = 14) or BFR-RT (n = 14) at 30% 1RM. Participants completed 8 weeks of biweekly unilateral leg press training on both limbs, totalling 16 sessions, alongside standard hospital rehabilitation. Resistance exercise protocols were designed consistent with standard recommended protocols for each type of exercise. Scaled maximal isotonic strength (10RM), muscle morphology of the vastus lateralis of the injured limb, self-reported function, Y-balance test performance and knee joint pain, effusion and range of motion (ROM) were assessed at pre-surgery, post-surgery, mid-training and post-training. Knee joint laxity and scaled maximal isokinetic knee extension and flexion strength at 60°/s, 150°/s and 300°/s were measured at pre-surgery and post-training. RESULTS: Four participants were lost, with 24 participants completing the study (12 per group). There were no adverse events or differences between groups for any baseline anthropometric variable or pre- to post-surgery change in any outcome measure. Scaled 10RM strength significantly increased in the injured limb (104 ± 30% and 106 ± 43%) and non-injured limb (33 ± 13% and 39 ± 17%) with BFR-RT and HL-RT, respectively, with no group differences. Significant increases in knee extension and flexion peak torque were observed at all speeds in the non-injured limb with no group differences. Significantly greater attenuation of knee extensor peak torque loss at 150°/s and 300°/s and knee flexor torque loss at all speeds was observed with BFR-RT. No group differences in knee extensor peak torque loss were found at 60°/s. Significant and comparable increases in muscle thickness (5.8 ± 0.2% and 6.7 ± 0.3%) and pennation angle (4.1 ± 0.3% and 3.4 ± 0.1%) were observed with BFR-RT and HL-RT, respectively, with no group differences. No significant changes in fascicle length were observed. Significantly greater and clinically important increases in several measures of self-reported function (50-218 ± 48% vs. 35-152 ± 56%), Y-balance performance (18-59 ± 22% vs. 18-33 ± 19%), ROM (78 ± 22% vs. 48 ± 13%) and reductions in knee joint pain (67 ± 15% vs. 39 ± 12%) and effusion (6 ± 2% vs. 2 ± 2%) were observed with BFR-RT compared to HL-RT, respectively. CONCLUSION: BFR-RT can improve skeletal muscle hypertrophy and strength to a similar extent to HL-RT with a greater reduction in knee joint pain and effusion, leading to greater overall improvements in physical function. Therefore, BFR-RT may be more appropriate for early rehabilitation in ACLR patient populations within the National Health Service.

Examination of the comfort and pain experienced with blood flow restriction training during post-surgery rehabilitation of anterior cruciate ligament reconstruction patients: A UK National Health Service trial.

OBJECTIVE: Examine the comfort and pain experienced with blow flow restriction resistance training (BFR-RT) compared to standard care heavy load resistance training (HL-RT) during anterior cruciate ligament reconstruction (ACLR) patient rehabilitation. DESIGN: Randomised controlled trial. SETTING: United Kingdom National Health Service. PARTICIPANTS: Twenty eight patients undergoing unilateral ACLR surgery with hamstring autograft were recruited. Following surgery participants were block randomised to either HL-RT at 70% repetition maximum (1RM) (n = 14) or BFR-RT (n = 14) at 30% 1RM and completed 8 weeks of twice weekly unilateral leg press training on both limbs. MAIN OUTCOME MEASURES: Perceived knee pain, muscle pain and rating of perceived exertion (RPE) were assessed using Borg's (1998) RPE and pain scales during training. Knee pain was also assessed 24 h post-training. RESULTS: There were no adverse events. Knee pain was lower with BFR-RT during (p < 0.05) and at 24 h post-training (p < 0.05) with BFR-RT for all sessions. Muscle pain was higher (p < 0.05) with BFR-RT compared to HL-RT during all sessions. RPE remained unchanged (p > 0.05) for both BFR-RT and HL-RT. CONCLUSION: ACLR patients experienced less knee joint pain and reported similar ratings of perceived exertion during and following leg press exercise with BFR-RT compared to traditional HL-RT. BFR-RT may be more advantageous during the early phases of post-surgery ACLR rehabilitation.

Sports-related injuries in New Zealand: National Insurance (Accident Compensation Corporation) claims for five sporting codes from 2012 to 2016.

OBJECTIVES: To provide epidemiological data and related costs for sport-related injuries of five sporting codes (cricket, netball, rugby league, rugby union and football) in New Zealand for moderate-to-serious and serious injury claims. METHODS: A retrospective analytical review using detailed descriptive epidemiological data obtained from the Accident Compensation Corporation (ACC) for 2012-2016. RESULTS: Over the 5 years of study data, rugby union recorded the most moderate-to-serious injury entitlement claims (25 226) and costs (New Zealand dollars (NZD$)267 359 440 (£139 084 749)) resulting in the highest mean cost (NZD$10 484 (£5454)) per moderate-to-serious injury entitlement claim. Rugby union recorded more serious injury entitlement claims (n=454) than cricket (t(4)=-66.6; P<0.0001); netball (t(4)=-45.1; P<0.0001); rugby league (t(4)=-61.4; P<0.0001) and football (t(4)=66.6; P<0.0001) for 2012-2016. There was a twofold increase in the number of female moderate-to-serious injury entitlement claims for football (RR 2.6 (95%CI 2.2 to 2.9); P<0.0001) compared with cricket, and a threefold increase when compared with rugby union (risk ratio (RR) 3.1 (95%CI 2.9 to 3.3); P<0.0001). Moderate-to-serious concussion claims increased between 2012 and 2016 for netball (RR 3.7 (95%CI 1.9 to 7.1); P<0.0001), rugby union (RR 2.0 (95% CI 1.6 to 2.4); P<0.0001) and football (RR 2.3 (95%CI 1.6 to 3.2); P<0.0001). Nearly a quarter of moderate-to-serious entitlement claims (23%) and costs (24%) were to participants aged 35 years or older. CONCLUSIONS: Rugby union and rugby league have the highest total number and costs associated with injury. Accurate sport exposure data are needed to enable injury risk calculations.

Effects of local versus remote ischemic preconditioning on repeated sprint running performance.

BACKGROUND: The aim of this study was to compare the effect of local and remote ischemic preconditioning (IPC) on repeated sprint exercise. METHODS: Twelve males (age 22±2 years; stature 1.79±0.07 m; body mass 77.8±8.4 kg; mean±SD) completed four trials consisting of remote (arm) and local (leg) IPC and SHAM interventions prior to repeated sprint exercise (3x[6x15+15-m] shuttle sprints), in a double-blind, randomized, crossover designed study. These tests were immediately preceded by IPC (4x5-minute intervals at 220 mmHg bilateral occlusion) or SHAM treatment (4x5-minute intervals at 20 mmHg bilateral occlusion). Sprint performance and percentage decrement score alongside measurement of Tissue Saturation Index, blood lactate and RPE were measured throughout the intervention. RESULTS: During the IPC/SHAM intervention there was a large decrease in TSI for IPC-arm in comparison to IPC-leg (P<0.05), however IPC-legs resulted in greater soreness compared with the other three conditions (P<0.05). There was no main effects or interaction effects for sprint performance. There was a significant effect of condition (P=0.047, r=0.56) on percentage decrement score across all 18 sprints with IPC demonstrating less fatigue than SHAM. There were no other effects of IPC during the sprint trials for any other physiological measure. CONCLUSIONS: In conclusion local IPC resulted in more pain/soreness during the IPC/SHAM intervention but both remote and local IPC reduced the fatigue associated with repeated sprint exercise.

Comparison of the acute perceptual and blood pressure response to heavy load and light load blood flow restriction resistance exercise in anterior cruciate ligament reconstruction patients and non-injured populations.

OBJECTIVES: To compare the acute perceptual and blood pressure responses to: 1) light load blood flow restriction resistance exercise (BFR-RE) in non-injured individuals and anterior cruciate ligament reconstruction (ACLR) patients; and 2) light load BFR-RE and heavy load RE (HL-RE) in ACLR patients. DESIGN: Between-subjects, partially-randomised. METHODS: This study comprised 3 groups: non-injured BFR-RE (NI-BFR); ACLR patients BFR-RE (ACLR-BFR); ACLR patients HL-RE (ACLR-HL). NI-BFR and ACLR-BFR performed 4 sets (30, 15, 15, 15 reps, total = 75 reps, 30s inter-set rest) of unilateral leg press exercise at 30% 1RM with continuous BFR at 80% limb occlusive pressure. ACLR-HL performed 3 × 10 reps (Total = 30 reps, 30s inter-set rest) of unilateral leg press exercise at 70% 1RM. Perceived exertion (RPE), muscle pain, knee pain and pre- and 5-min post-exercise blood pressure were measured. RESULTS: RPE was higher in ACLR-BFR compared to NI-BFR (p < 0.05). Muscle pain was higher in NI-BFR and ACLR-BFR compared to ACLR-HL (p < 0.05). Knee pain was lower in ACLR-BFR compared to ACLR-HL (p < 0.01). There were no differences in blood pressure. CONCLUSION: These responses to BFR exercise may not limit application and favourably influence knee pain throughout ACLR rehabilitation training programmes. These findings can help inform practitioners' decisions to utilise this tool.

Time to get our four priorities right: an 8-year prospective investigation of 1326 player-seasons to identify the frequency, nature, and burden of time-loss injuries in elite Gaelic football.

Managing injury risk requires an understanding of how and when athletes sustain certain injuries. Such information guides organisations in establishing evidence-based priorities and expectations for managing injury risk. In order to minimise the impact of sports injuries, attention should be directed towards injuries that occur frequently, induce substantial time-loss, and elevate future risk. Thus, the current study aimed to investigate the rate at which elite Gaelic football players sustain different time-loss injuries during match-play and training activities. Datasets (n = 38) from elite Gaelic football teams (n = 17) were received by the National Gaelic Athletic Association Injury Surveillance Database from 2008 to 2016. A total of 1,614 time-loss injuries were analysed. Each season teams sustained 24.0 (interquartile ranges) (IQR 16.0-32.0) and 15.0 (IQR 10.0-19.0) match-play and training injuries, respectively. When exposure was standardised to 1,000 h, greater rates of injury (12.9, 95% CI [11.7-14.3]) and time-loss days (13.4, 95% CI [12.3-14.9]) were sustained in match-play than in training. Acute injury rates were 3.1-times (95% CI [2.7-3.4]) greater than chronic/overuse injuries. Similarly, non-contact injury rates were 2.8-times (95% CI [2.5-3.2]) greater than contact injuries. A total of 71% of injuries in elite Gaelic football affected five lower limb sites. Four lower limb-related clinical entities accounted for 40% of all time-loss injuries (hamstring, 23%; ankle sprain, 7%; adductor-related, 6%; quadriceps strain, 5%). Thus, most risk management and rehabilitation strategies need to be centred around five lower limb sites-and just four clinical entities. Beyond these, it may be highly unlikely that reductions in injury susceptibility can be attributed to specific team interventions. Thus, compliance with national databases is necessary to monitor injury-related metrics and future endeavours to minimise injury risk.

Influence and reliability of lower-limb arterial occlusion pressure at different body positions.

BACKGROUND: Total arterial occlusive pressure (AOP) is used to prescribe pressures for surgery, blood flow restriction exercise (BFRE) and ischemic preconditioning (IPC). AOP is often measured in a supine position; however, the influence of body position on AOP measurement is unknown and may influence level of occlusion in different positions during BFR and IPC. The aim of this study was therefore to investigate the influence of body position on AOP. METHODS: Fifty healthy individuals (age = 29 ± 6 y) underwent AOP measurements on the dominant lower-limb in supine, seated and standing positions in a randomised order. AOP was measured automatically using the Delfi Personalised Tourniquet System device, with each measurement separated by 5 min of rest. RESULTS: Arterial occlusive pressure was significantly lower in the supine position compared to the seated position (187.00 ± 32.5 vs 204.00 ± 28.5 mmHg, p < 0.001) and standing position (187.00 ± 32.5 vs 241.50 ± 49.3 mmHg, p < 0.001). AOP was significantly higher in the standing position compared to the seated position (241.50 ± 49.3 vs 204.00 ± 28.5 mmHg, p < 0.001). DISCUSSION: Arterial occlusive pressure measurement is body position dependent, thus for accurate prescription of occlusion pressure during surgery, BFR and IPC, AOP should be measured in the position intended for subsequent application of occlusion.

Reported concussion incidence in youth community Rugby Union and parental assessment of post head injury cognitive recovery using the King-Devick test.

AIM: To assess the frequency of reported head injuries in youth community Rugby Union and determine whether the King-Devick (K-D) test could be used by parents as a means to chart cognitive recovery following head injury. METHODS: A prospective cohort study of 489 junior players (U9-U18) conducted at a community level Rugby Union club over four seasons. All players undertook a baseline K-D test at the start of each season. Players identified with suspected concussion performed the K-D test post injury and results were compared to their most recent baseline assessment. Parent/Guardians of the player then oversaw repeated daily testing until baseline scores were surpassed. RESULTS: 49 players were sent for assessment after suspected head injury. 46 parents oversaw daily repeated K-D testing (93.8% engagement). The median reduction in K-D test performance speed post-injury from baseline was 7.32 s (IQR 2.46 - 7.98). A median of 5.1 days/tests were taken for players to surpass baseline performance. No correlation was found between initial post-injury test and cognitive recovery time. 38 head injuries were reported from match play with an incidence rate of 12.7 per 1000 match hours (95% CI 9.2-17.5). CONCLUSION: The K-D test is a practical tool for baseline, post injury and parentally supervised repeated testing within youth community Rugby Union. Incidence of reported head injuries following match play is higher than previously reported. Parental engagement was high. Post-Injury K-D test performance should not be used as a means to predict symptom recovery.

Eccentric knee flexor strength profiles of 341 elite male academy and senior Gaelic football players: Do body mass and previous hamstring injury impact performance?

OBJECTIVE: Report eccentric knee flexor strength values of elite Gaelic football players from underage to adult level whilst examining the influence of body mass and previous hamstring injury. DESIGN: Cross-sectional study. SETTING: Team's training facility. PARTICIPANTS: Elite Gaelic football players (n = 341) from under 14 years to senior age-grades were recruited from twelve teams. MAIN OUTCOME MEASURES: Absolute (N) and relative (N·kg-1) eccentric hamstring strength as well as corresponding between-limb imbalances (%) were calculated for all players. RESULTS: Mean maximum force was 329.4N (95% CI 319.5-340.2) per limb. No statistically significant differences were observed in relative force values (4.4 N ·kg-1, 95% CI 4.2-4.5) between age-groups. Body mass had moderate-to-large and weak associations with maximum force in youth (r = 0.597) and adult (r =0 .159) players, respectively. Overall 40% (95 CI 31.4-48.7) presented with a maximum strength between-limb imbalance >10%. Players with a hamstring injury had greater relative maximum force (9.3%, 95% CI 7.0-11.8; p > 0.05) and a 28% (95% CI 10.0-38.0) higher prevalence of between-limb imbalances ≥15% compared to their uninjured counterparts. CONCLUSIONS: Overlapping strength profiles across age-groups, combined with greater strength in previously injured players, suggests difficulties for establishing cut-off thresholds associated with hamstring injury risk.

Caffeine and Physiological Responses to Submaximal Exercise: A Meta-Analysis.

The aim of this study was to carry out a systematic review and meta-analysis of the effects of caffeine supplementation on physiological responses to submaximal exercise. A total of 26 studies met the inclusion criteria of adopting double-blind, randomized crossover designs that included a sustained (5-30 min) fixed-intensity bout of submaximal exercise (constrained to 60-85% maximal rate of oxygen consumption) using a standard caffeine dose of 3-6 mg·kg-1 administered 30-90 min prior to exercise. Meta-analyses were completed using a random-effects model, and data are presented as raw mean difference (D) with associated 95% confidence limits (CLs). Relative to placebo, caffeine led to significant increases in submaximal measures of minute ventilation (D = 3.36 L·min-1; 95% CL, 1.63-5.08; P = .0001; n = 73), blood lactate (D = 0.69 mmol·L-1; 95% CL, 0.46-0.93; P < .00001; n = 208), and blood glucose (D = 0.42 mmol·L-1; 95% CL, 0.29-0.55; P < .00001; n = 129). In contrast, caffeine had a suppressive effect on ratings of perceived exertion (D = -0.8; 95% CL, -1.1 to -0.6; P < .00001; n = 147). Caffeine had no effect on measures of heart rate (P = .99; n = 207), respiratory exchange ratio (P = .18; n = 181), or oxygen consumption (P = .92; n = 203). The positive effects of caffeine supplementation on sustained high-intensity exercise performance are widely accepted, although the mechanisms to explain that response are currently unresolved. This meta-analysis has revealed clear effects of caffeine on various physiological responses during submaximal exercise, which may help explain its ergogenic action.