Traumatic and overuse injuries among international elite junior rowers

The Rowing Spine: A Review of Biomechanics, Injury, and Treatment

OBJECTIVE

We aimed to describe spinal biomechanics and injury patterns in rowing.

METHODS

In this systematic literature review, a Google and PubMed literature search was undertaken using keywords "rowing," "biomechanics," and "spine."

RESULTS

Relevant articles were reviewed and synthesized to describe biomechanics, injury patterns, treatment options, and techniques for injury prevention.

CONCLUSIONS

Rowing has increased in popularity throughout the United States. Up-to-date knowledge of rowing biomechanics and spinal injury patterns is necessary for prompt diagnosis and appropriate treatment of the injured rowing athlete.

Acute effects of muscle mechanical properties after 2000-m rowing in young male rowers

Background

The mechanical properties of muscles, such as changes in muscle tone and stiffness, are related to sports performance and injuries. Rowers are at increased risk of muscle fatigue and injury during high-repetition and heavy-load cyclic muscle actions. In view of this, the aim of the present study was to investigate the acute effect on muscle tone and stiffness, as well as bilateral muscle asymmetry, in high school rowers after a 2000-meter rowing ergometer test.

Methods

Twelve young male rowers (age = 17.1 ± 0.9 years, body weight = 73.5 ± 9.7 kg) were included in the study. The data of muscle tone (frequency) and stiffness of the posterior deltoids (PD), latissimus dorsi (LD), and rectus femoris (RF) (dominant and non-dominant side) before and after a 2000-m rowing ergometer test were collected using a handheld MyotonPRO device.

Results

After the rowing ergometer test, the muscle tone of dominant side PD, LD, and RF were significantly increased (p < 0.05). On the other hand, the muscle stiffness of the non-dominant side LD and RF, as well as the dominant side PD, LD, and RF were significantly increased after the rowing ergometer test (p < 0.05). The muscle tone and stiffness results showed that the dominant side PD, LD, and RF were all significantly higher than the non-dominant side after the rowing ergometer test (p < 0.05), where bilateral PD and RF exhibits moderate asymmetry (5% < symmetry index < 10%).

Conclusions

After a high-intensity and high-load 2000-m rowing ergometer test, PD, LD, and RF showed increases in muscle tone and stiffness, as well as changes in the symmetry of bilateral muscle mechanical properties.

The acute effects of kinesio-taping on movement kinematics and muscle co-activation in rowing athletes

BACKGROUND

Rowing-related low back disorders may occur from inconsistent technique, high trunk flexion and training volumes, overactivation of paraspinal muscles, and fatigue.

OBJECTIVE

To examine if kinesiology tape (KT) affixed to the trunk dorsum affects muscular co-activation and neuromuscular control to limit dangerous rowing movements and associated injuries.

METHODS

Participants (n= 18) completed two 2000 m rowing trials under BASELINE and KT conditions. KT was applied to the skin superficial to the paraspinals bilaterally with 60% pre-strain. Participants were instructed to minimize any sensation of tension. Whole body kinematics were obtained using inertial measurement units (IMUs), and surface electromyograms (EMGs) were recorded from trunk and lower extremity. Changes in joint range-of-motion (ROM) and co-activation indices (CAIs) were analyzed for shoulder, lumbar, hip, and knee.

RESULTS

Responding participants (n= 5) were identified by reduced maximum lumbar flexion during the KT condition. As expected, significant differences occurred in maximum and minimum lumbar flexion/extension between responders and non-responders to KT. Additionally, there was significant reduction in mean trunk muscle co-activation in both those who did and did not respond to KT through reductions in maximum lumbar flexion.

CONCLUSION

KT can be an effective at reducing mean trunk co-activation during a rowing trial in the flexed catch position. Variable responses suggest that further work is necessary to optimize the efficacy of sensory cues derived from KT during rowing movements.

Advanced muscle imaging in adolescent elite rowers utilizing diffusion tensor imaging: Association of imaging findings with stroke typology

PURPOSE

Muscular overuse injuries are a common health issue in elite athletes. Changes in the muscular microenvironment can be depicted by Diffusion Tensor Imaging (DTI). We hypothesize that the biomechanics of different stroke typologies plays a role in muscle injury and tested our hypothesis by magnetic resonance imaging (MRI) examination of the lumbar spine muscles of adolescent rowers utilizing DTI.

METHODS AND MATERIALS

Twenty-two male elite rowers (12 sweep, 10 scull rowers) with a mean age of 15.8 ± 1.2 years underwent 3-Tesla MRI of the lumbar spine 6 hours after cessation of training. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were calculated for the erector spinae and multifidus muscle. Student's t-test was used to test differences of DTI parameters between sweep and scull rowers and a Pearson correlation was utilized to correlate the parameters to training volume.

RESULTS

ADC values in the erector spinae and multifidus muscle were significantly higher (p = 0.039) and FA values significantly lower (p < 0.001) in sweep rowers compared to scull rowers. There was no significant association between DTI parameters and training volume (r ≤ -0.459, p ≥ 0.074).

CONCLUSIONS

Our DTI results show that lumbar spine muscle diffusivity is higher in sweep rowers than in scull rowers. Altered muscle diffusivity is suggestive of microscopic tissue disruption and might be attributable to biomechanical differences between stroke typologies.

Epidemiology of Injuries in Professional and Amateur Football Men (Part II)

Background (1): Men's football is a physically demanding contact sport that involves intermittent bouts of sprinting, jogging, walking, jumping and changes of direction. The physical demands of the game vary by level of play (amateur club, sub-elite and open club or international), but injury rates at all levels of the men's football game remain the highest of all sports. Objective: The aim of this study is to conduct a systematic review of data from the epidemiological literature regarding the profile, severity and mechanisms of injuries and the frequency of recurrent injuries in professional and amateur football players. Methods (2): A systematic review, according to PRISMA guidelines, was performed up to June 2023 in the databases of PubMed, Web of Science, Google academic, Google scholar and the Diva portal. Twenty-seven studies that reported data on the type, severity, recurrence and mechanisms of injury in professional and amateur men's football were selected and analyzed. Two reviewers independently audited data and assessed the study quality using the additional and adapted version of the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement and the Newcastle Ottawa Scale (NOS) to assess risk of bias for the quality of external validity. Results (3): In professional male football players, the mean prevalence of muscle/tendon injuries was 39.78%, followed by joint and ligament injuries-21.13%, contusions-17.86%, and fractures-3.27%, and for amateur football players, the prevalence's were 44.56% (muscle/tendon injuries), 27.62% (joint and ligament injuries), 15.0% (contusions) and 3.05% (fracture), respectively. The frequency of traumatic injuries was higher in amateur football players (76.88%) compared to professional football players (64.16%), the situation being reversed in the case of overuse injuries: 27.62% in professional football players and 21.13% in amateur football players. Most contact injuries were found in professional footballers (50.70%), with non-contact injuries predominating in amateur footballers (54.04%). The analysis of the severity of injuries showed that moderate injuries dominated in the two categories of footballers; the severe injuries in amateur footballers exceeded the severe injuries recorded in professional footballers by 9.60%. Recurrence proportions showed an inverse relationship with the level of play, being higher in amateur footballers (16.66%) compared to professional footballers (15.25%). Conclusions (4): Football-related injuries have a significant impact on professional and amateur football players and their short- and long-term health status. Knowing the frequency of severe diagnoses, such as strains, tears and cramps of the thigh muscles, ankle ligament sprains and hip/groin muscle strain requires the establishment of adequate programs to prevent them, especially in amateur football players, who are more prone to serious injuries.

The Kinematics of Fixed-Seat Rowing: A Structured Synthesis

Olympic-style sliding-seat rowing is a sport that has been extensively researched, with studies investigating aspects related to the physiology, biomechanics, kinematics, and the performance of rowers. In contrast, studies on the more classic form of fixed-seat rowing are sparse. The aim of this study is to address this lacuna by analysing for the first time the specific kinematics of fixed-seat rowing as practised by able-bodied athletes, thus (i) documenting how this technique is performed in a manner that is replicable by others and (ii) showing how this technique compares and contrasts with the more standard sliding-seat technique. Fixed-seat rowing was replicated in a biomechanics laboratory where experienced fixed-seat rowers, marked with reflective markers following the modified Helen-Hayes model, were asked to row in a manner that mimics rowing on a fixed-seat boat. The findings from this study, complimented with data gathered through the observation of athletes rowing on water, were compared to sliding-seat ergometer rowing and other control experiments. The results show that, in fixed-seat rowing, there is more forward and backward thoracic movement than in sliding-seat rowing (75-77° vs. 44-52°, p < 0.0005). Tilting of the upper body stems was noted to result from rotations around the pelvis, as in sliding-seat rowing, rather than from spinal movements. The results also confirmed knee flexion in fixed-seat rowing with a range of motion of 30-35°. This is less pronounced than in standard-seat rowing, but not insignificant. These findings provide a biomechanical explanation as to why fixed-seat rowers do not have an increased risk of back injuries when compared with their sliding-seat counterparts. They also provide athletes, coaches, and related personnel with precise and detailed information of how fixed-seat rowing is performed so that they may formulate better and more specific evidence-based training programs to meliorate technique and performance.

Physiological and biomechanical responses to exercise on two different types of rowing ergometers in NCAA Division I oarswomen

BACKGROUND

Stationary (SE) and dynamic (DE) rowing ergometers, that are utilized for indoor training and physical assessment of competitive rowers, may elicit different physiological and biomechanical responses. The present study used SE and DE ergometers to examine submaximal and peak physiological and biomechanical responses during an incremental rowing test.

METHODS

Twelve National Collegiate Athletic Association (NCAA) Division I oarswomen performed seven-stage rowing tests with the last stage performed with maximal effort. Heart rate (HR), lactate (LA), oxygen uptake (VO₂), ventilation (VE), stroke rate (SR), gross efficiency (GE), and rating of perceived exertion (RPE) were obtained; while trunk, hip, knee, shoulder, and elbow ranges of motion (ROM) were measured.

RESULTS

SR was higher at maximal stage DE (29.3 vs. 34.8 strokes/min, p = 0.018, d = 1.213). No difference occurred in responses of maximal stage HR, RPE, VO2, VE, LA, or GE between the two ergometers. Submaximal LA and SR were greater on the DE for all submaximal stages. Submaximal VE was greater on the DE for all submaximal stages except Stage 3 (p = 0.160, d = 0.655). VO₂ was higher on the DE Stages 2-5. GE was higher on the SE for Stages 2-5. Athletes showed increased trunk (p = 0.025, [Formula: see text] = 0.488) and knee (p = 0.004, [Formula: see text] = 0.668) ROM on SE.

CONCLUSION

Rowing on the DE appears to elicit a greater stroke rate and more optimal joint angles especially at high intensities. Hence, the DE is worthy of consideration as a preferred ergometer for women rowers.

Examining the Peer-Reviewed Published Literature Regarding Low Back Pain in Rowing: A Scoping Review

Background

Low back pain (LBP) is highly prevalent in the rowing population. The body of existing research variously investigates risk factors, prevention, and treatment methods.

Purpose

The purpose of this scoping review was to explore the breadth and depth of the LBP literature in rowing and to identify areas for future research.

Study Design

Scoping review.

Methods

PubMed, Ebsco and ScienceDirect were searched from inception to November 1, 2020. Only published, peer-reviewed, primary, and secondary data pertaining to LBP in rowing were included for this study. Arksey and O'Malley's framework for guided data synthesis was used. Reporting quality of a subsection of the data was assessed using the STROBE tool.

Results

Following the removal of duplicates and abstract screening, a set of 78 studies were included and divided into the following categories: epidemiology, biomechanics, biopsychosocial, and miscellaneous. The incidence and prevalence of LBP in rowers were well mapped. The biomechanical literature covered a wide range of investigations with limited cohesion. Significant risk factors for LBP in rowers included back pain history and prolonged ergometer use.

Conclusion

A lack of consistent definitions within the studies caused fragmentation of the literature. There was good evidence for prolonged ergometer use and history of LBP to constitute risk factors and this may assist future LBP preventative action. Methodological issues such as small sample size and barriers to injury reporting increased heterogeneity and decreased data quality. Further exploration is required to determine the mechanism of LBP in rowers through research with larger samples.

Sport-related injuries in Iranian basketball players: evidence from a retrospective epidemiologic study (2019-20)

OBJECTIVES

Basketball is a contact sport with complex movements that include jumps, turns, and changes in direction, which cause frequent musculoskeletal injuries in all regions of the body. Also, injury patterns among athletes, particularly basketball players, continue to evolve and change. The current retrospective epidemiologic study aimed to investigate the incidence, severity, and sports-related risk factors of injuries in Iranian basketball players from 2019 to 2020.

METHODS

Using the Information Retrospective Injury Questionnaire (online version), data on basketball-related injuries were collected retrospectively for 204 basketball players of the Iranian league (professional super league and first-division league) during the 2019/2020 season.

RESULTS

A total of 628 injuries were reported, which was equivalent to 6.07 injuries/1000 h. The ankle was the location of most injuries (n = 116 or 26.9%; overuse injuries (n = 40 or 20.3%)), followed by lower back/pelvis injuries (acute injury n = 67 (15.5%) and overuse injuries (n = 23; 11.6%)), knee injuries (acute injury n = 62 (15.7%) and overuse injuries (n = 31 (14.3%)), wrist/fingers injuries (acute injury (n = 85 (13.4%)) and overuse injuries (n = 8; 4.0%)), and shin/calf injuries (acute injury (n = 35; 8.1%) and overuse injuries (n = 28; 14.2%)). Mean time loss in first-division league players was much higher than professional super league players (7.84/1000 h exposure vs. 4.30/1000 h exposure), respectively.

CONCLUSION

The ankle sprain was the most common injury in our study. Lower back/pelvis injuries had the longest time loss. Injury was more frequent among first-division league players than those in the professional super league. Injuries during practice were notably more frequent than during competition with different patterns of injuries.

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.

Update on injury epidemiology in rowing: our experience with female NCAA Division I athletes and a systematic review of the literature

OBJECTIVES

(1) To report the distribution of injuries per body site and time lost from participation in female NCAA Division I rowers and (2) to present an updated summary of the existing evidence regarding the analysis of injuries per body site in rowers.

METHODS

Case series: The distribution of injuries per body site in female NCAA Division I rowers and the time lost from participation were retrieved from an institutional registry. Injuries per body site were reported as number of athletes with site-specific injury per total number of injured athletes. Systematic review: Based on the PRISMA guidelines for systematic reviews, three electronic databases were searched for studies reporting the epidemiology of injuries per body site in rowers and analyzed.

RESULTS

Case series: One-hundred and thirty-seven injuries were recorded in 92 female rowers over 5 years. The risk of injury (number of injured athletes over total number of athletes on roaster) was 52% (92/176). Among the 92 injured athletes, 38% sustained injury to the lower back, while 23% and 16% of these athletes sustained injury to the ribs and hip-groin area, respectively. Systematic review: Ten studies were included. The level of evidence was IV and the mean MINORS score was 13.2(9-15) (fair quality). Most studies reported injuries to the lower spine (8/10,80%) whereas injuries to the ribs or other anatomic sites were reported in ≤4 (40%) studies. Significant heterogeneity of the injury reporting methodologies (injury definition; measures of injury occurrence; description of the injury site) was detected and precluded meta-analysis.

CONCLUSIONS

Most injuries recorded in a single team of female NCAA Division I athletes occurred in the lower back followed by injuries to the ribs and the hip. The existing injury epidemiology literature in mostly focuses on injuries to the lower back, while injuries to other anatomic sites were less frequently analyzed. No conclusions can be made regarding the most common injuries in rowers based on the current evidence due to substantial heterogeneity of injury reported methodologies which warrants further investigation.

Patterns of Intervertebral Disk Alteration in Asymptomatic Elite Rowers: A T2* MRI Mapping Study

Background:

Repetitive loading of the back puts elite rowers at risk for acute and chronic back injuries.

Hypothesis:

That asymptomatic elite rowers would demonstrate characteristic intervertebral disk (IVD) alterations on T2* magnetic resonance imaging (MRI) mapping compared with asymptomatic nonrowers.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

This study included 20 asymptomatic elite rowers (mean age, 23.4 ± 3.03 years; 9 women, 11 men) studied at 2 different times, once before (t₁) and once after (t₂) the competition phase. MRI including T2* mapping was performed on a 3-T scanner. The authors derived normative T2* data from a previous study on 40 asymptomatic volunteers (20 men, 20 women) who were not competitive rowers; based on complete T2* data sets, 37 controls were included. T2* values were compared between groups in 4 lumbar IVDs, and midsagittal T2* values were compared in 5 zones: anterior annulus fibrosus (AF), anterior nucleus pulposus (NP), central NP, posterior NP, and posterior AF. The Pfirrmann grade was used for morphological assessment of disk degeneration. Statistical analysis was conducted using the Mann-Whitney U test, Wilcoxon matched-pairs test, and Spearman rank correlation coefficient.

Results:

Lower T2* values were noted in the rower group compared with the controls (37.08 ± 33.63 vs 45.59 ± 35.73 ms, respectively; P < .001). The intersegmental comparison revealed lower mean T2* values among rowers (P ≤ .027 for all). The interzonal comparison indicated significantly lower mean T2* values for the rowers in all zones except for the anterior NP (P ≤ .008 for all). Lower mean T2* values were observed for the rowers at t₁ versus t₂ (39.25 ± 36.19 vs 43.97 ± 38.67 ms, respectively; P = .008). The authors noted a higher level of IVD damage according to Pfirrmann assessment in the rower cohort (P < .001); the Pfirrmann grade distributions of rowers versus controls, respectively, were as follows: 51.3% versus 73.7% (grade 1), 20.5% versus 19.5% (grade 2), 21.8% versus 6.8% (grade 3), 5.1% versus 0% (grade 4), and 1.3% versus 0% (grade 5). The authors also noted a correlation between low T2* and high Pfirrmann grade at t₁ (r =–0.48; P < .001) and t₂ (r =–0.71; P < .001).

Conclusion:

The cohort of elite rowers revealed more degenerative IVD changes compared with controls. The T2* values suggest that repetitive loading of the spine has demonstrable short-term and possibly permanent effects on the lumbar IVD.

Common health issues and advised treatments reported in an ultraendurance ocean rowing race

Objectives

Ocean rowing is an extreme ultraendurance sport where individuals row unsupported across an ocean. This can mean months at sea in unpredictable and inhospitable conditions. The extreme physical and mental demands associated mean medical issues are common yet under researched, impacting the medical assistance provided.

Methods

The Talisker Whisky Atlantic Challenge provides a framework with safety protocols to create safer environments for athletes to attempt transatlantic crossings. Race logs, which record communication between rowers and safety teams, were anonymised and examined to create cumulative totals of medical issues requiring help and an incident timeline.

Results

Duty officers were notified of 65 medical complaints, 32% (n=21) requiring race doctors. Dermatological conditions were most common, accounting for 32% of complaints (n=21) and affecting 24% of rowers. Pressure sores and infections represented 43% and 38% of dermatological complaints respectively. Musculoskeletal injuries equalled 18% (n=12) of complaints, affecting 20% of rowers. Most cases were reported in weeks one and three, with 37% (n=24) of issues and 90% (n=10) of seasickness cases in week one. Hygiene and antibiotics were frequently advised management options.

Conclusion

Conditions requiring race doctor input represent the most severe cases with the potential to deteriorate. Managing dermatological and musculoskeletal issues is vital throughout the race, while seasickness prophylaxis and education is essential in initial race stages. Infections are cause for concern, with gluteal pressure sores a potential route for secondary infections. Further research is required before evidence-based guidelines for management of health issues in ocean rowers can be introduced.

Imaging of exercise-induced spinal remodeling in elite rowers

OBJECTIVES

As in-vivo knowledge of training-induced remodeling of intervertebral discs (IVD) is scarce, this study assessed how lumbar IVDs change as a function of long-term training in elite athletes and age-matched controls using compositional Magnetic Resonance Imaging (MRI).

DESIGN

Prospective case-control study.

METHODS

Prospectively, lumbar spines of 17 elite rowers (ERs) of the German national rowing team (mean age: 23.9 ± 3.3 years) were imaged on a clinical 3.0 T MRI scanner. ERs were imaged twice during the annual training cycle, i.e., at training intensive preseason preparations (t₀) and 6 months later during post-competition recovery (t₁). Controls (n = 22, mean age: 26.3 ± 1.9 years) were imaged once at corresponding time points (t₀: n = 11; t₁: n = 11). Segment-wise, the glycosaminoglycan (GAG) content of lumbar IVDs (n = 195) was determined using glycosaminoglycan chemical exchange saturation transfer (gagCEST). Linear mixed models were set up to assess the influence of cohort and other variables on GAG content.

RESULTS

During preseason, IVD GAG values of ERs were significantly higher than those of controls (ERs(t₀): 2.58 ± 0.27% (mean ± standard deviations); controls(t₀): 1.43 ± 0.36%; p ≤ 0.001), while during post-competition recovery, such differences were not present anymore (ERs(t₁): 2.11 ± 0.18%; controls(t₁): 1.89 ± 0.24%; p = 0.362).

CONCLUSIONS

Professional elite-level rowing is transiently associated with significantly higher gagCEST values, which indicate increased lumbar IVD-GAG content and strong remodeling effects in response to training. Beyond professional rowing, core-strengthening full-body exercise may help to enhance the resilience of the lumbar spine as a potential therapeutic target in treating back pain.

The Occupational Military Neuromusculoskeletal Injury Matrix

INTRODUCTION

Neuromusculoskeletal injuries (NMSKIs) are the primary cause of ambulatory visits, lost duty days, and disability discharges in the U.S. Military. Methods for accurately grouping injury diagnoses are required to allow for surveillance and research identifying risk factors and prevention strategies. The CDC method of grouping these diagnoses includes only the S and T codes (Injury, poisoning, and certain other consequences of external causes) from the ICD-10-CM. However, this does not include the majority of the NMSKI depleting soldier readiness; the M (Disease of the musculoskeletal system and connective tissue) and G (Diseases of the nervous system) codes should be included as these also contain injuries. The goal was to develop a new matrix that would comprehensively capture all NMSKIs experienced by military personnel. This paper details the development of the Occupational Military Neuromusculoskeletal Injury (OMNI) Matrix and characterizes the number and rates of active duty U.S. Army injuries as measured by the OMNI compared to other matrices.

MATERIALS AND METHODS

A team of researchers including physical therapists, physician assistants, occupational therapists, physicians, and epidemiologists developed the OMNI. The OMNI utilizes the commonly accepted injury definition inclusive of any anatomical complaint resulting in pain or dysfunction and categorizes injuries from the G, M, S, and T codes. The OMNI follows the CDC's matrix structure with three body region levels, each becoming more specific, and adds two levels called Description of the Injury. Additionally, the OMNI categorizes injuries as Injury Type (Acute, Overuse, Either, or Not Applicable), NMSKI-Type (NMSKI, NMSKI that could be caused by occupational/training tasks, and not an NMSKI), and a miscellaneous category that demarks injuries as Superficial, Blood Vessels, and/or Internal Organs. The different grouping methods in the OMNI provide standardization for many possible injury case definitions. The OMNI allows these injury categories to be included/excluded in a standardized fashion to meet the researchers' scientific questions. To enumerate the number of NMSKI that would be captured by the available matrices, the OMNI, the CDC's matrix, and the U.S. Army Public Health Center's (APHC) Taxonomy of Injuries were applied to active duty Army outpatient population data and all incident NMSKI diagnostic codes entered in electronic medical provider encounters for calendar years 2017 and 2018.

RESULTS

Using the OMNI resulted in the capture of over 800,000 more injuries than the CDC's matrix and over 200,000 more than the APHC Taxonomy. The NMSKI rate utilizing the OMNI was 193 per 100 soldier-years in 2017 (892,780 NMSKI) compared to 23 per 100 soldier-years for the CDC's matrix, and 141 per 100 soldier-years for the APHC Taxonomy.

CONCLUSION

The OMNI provides an updated standardized method of assessing injuries, particularly in occupational military injury research, that can be utilized for Military Performance Division of injury across many countries and still allow for replication of methods and comparison of results. Additionally, the OMNI has the capacity to capture a greater burden of injury beyond what is captured by other available matrices.

Lumbar Intervertebral Disc Degeneration Does Not Affect Muscle Synergy for Rowing Activities

Rowers with disc degeneration may have motor control dysfunction during rowing. This study is aimed at clarifying the trunk and lower extremity muscle synergy during rowing and at comparing the muscle synergy between elite rowers with and without lumbar intervertebral disc degeneration. Twelve elite collegiate rowers (with disc degeneration, n = 6; without disc degeneration, n = 6) were included in this study. Midline sagittal images obtained by lumbar T2-weighted magnetic resonance imaging were used to evaluate disc degeneration. Participants with one or more degenerated discs were classified into the disc degeneration group. A 2000 m race trial using a rowing ergometer was conducted. Surface electrodes were attached to the right rectus abdominis, external oblique, internal oblique, latissimus dorsi, multifidus, erector spinae, rectus femoris, and biceps femoris. The activity of the muscles was measured during one stroke immediately after 20% and 80% of the rowing trial. Nonnegative matrix factorization was used to extract the muscle synergies from the electromyographic data. To compare the muscle synergies, a scalar product (SP) evaluating synergy coincidence was calculated, and the muscle synergies were considered identical at SP > 75%. Both groups had only one module in the 20% and 80% time points of the trial. At the 20% time point of the 2000 m rowing trial, the SP of the module was 99.8%. At the 80% time point, the SP of the module was 99.9%. The SP results indicate that, at 20% and 80% time points, both groups had the same module. The module showed a high contribution in all muscles. The activation coefficients indicated that the module was always highly activated throughout the rowing stroke in both groups. The trunk and lower extremity muscles are mobilized through the rowing stroke and maintain coordination during rowing. There was no difference in the muscle synergy between the rowers with and without lumbar intervertebral disc degeneration.

The relationship between rowing-related low back pain and rowing biomechanics: a systematic review

BACKGROUND

Low back pain (LBP) is common in rowers. Understanding rowing biomechanics may help facilitate prevention and improve rehabilitation.

OBJECTIVES

To define the kinematics and muscle activity of rowers and to compare with rowers with current or LBP history.

DESIGN

Systematic review.

DATA SOURCES

EMBASE, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Web of Science and Scopus from inception to December 2019. Grey literature was searched.

STUDY ELIGIBILITY CRITERIA

Experimental and non-experimental designs.

METHODS

Primary outcomes were kinematics and muscle activity. Modified Quality Index (QI) checklist was used.

RESULTS

22 studies were included (429 participants). Modified QI score had a mean of 16.7/28 points (range: 15-21). Thirteen studies investigated kinematics and nine investigated muscle activity. Rowers without LBP ('healthy') have distinct kinematics (neutral or anterior pelvic rotation at the catch, greater hip range of motion, flatter low back spinal position at the finish) and muscle activity (trunk extensor dominant with less flexor activity). Rowers with LBP had relatively greater posterior pelvic rotation at the catch, greater hip extension at the finish and less efficient trunk muscle activity. In both groups fatigue results in increased lumbar spine flexion at the catch, which is greater on the ergometer. There is insufficient evidence to recommend one ergometer type (fixed vs dynamic) over the other to avoid LBP. Trunk asymmetries are not associated with LBP in rowers.

CONCLUSION

Improving clinicians' and coaches' understanding of safe and effective rowing biomechanics, particularly of the spine, pelvis and hips may be an important strategy in reducing incidence and burden of LBP.

Implementation of Injury and Illness Surveillance Protocols in Varsity Athletes

OBJECTIVE

To develop and implement a prospective varsity athlete surveillance system to identify injury and illness trends in a multisport varsity-level university setting.

DESIGN

Longitudinal prospective surveillance study.

SETTING

Varsity-level sport program at the University of Guelph, Guelph, ON, Canada.

PARTICIPANTS

Athletic therapists (ATs) (n = 35) from 17 varsity sports provided injury and illness information on 624 varsity-level athletes (381 men and 243 women) during the 2016/2017 competitive season.

INTERVENTIONS

Team ATs reported athlete health complaints weekly. Athletes reported additional details on the injury or illness that was reported.

MAIN OUTCOME MEASURES

The outcome measurements included when the injury or illness occurred, anatomical location, diagnosis, cause, perceived severity, treatment, estimated athlete exposure (AE) to training and competition, and time loss from sport. Measures were recorded from the teams' first competition through to the end the season and/or playoffs.

RESULTS

Twenty-nine of 30 varsity sports teams participated in this injury and illness surveillance protocol. The compliance of team ATs and varsity athletes was 89% (men: 94%, women: 82%). The overall injury and illness rates were 5.5 injuries and 1.7 illnesses per 1000 AEs, respectively. Men's injury rates were greater than women's, and injury rates of contact sports were greater than noncontact sports.

CONCLUSIONS

The utilization of a prospective injury and illness surveillance protocol in the Canadian University sport system is feasible with good athlete, AT, and coach acceptance. The surveillance data should inform future injury and illness prevention strategies.

Epidemiology of injury and illness in 153 Australian international-level rowers over eight international seasons

Aim

To report the epidemiology of injury and illness in elite rowers over eight seasons (two Olympiads).

Methods

All athletes selected to the Australian Rowing Team between 2009 and 2016 were monitored prospectively under surveillance for injury and illness. The incidence and burden of injury and illness were calculated per 1000 athlete days (ADs). The body area, mechanism and type of all injuries were recorded and followed until the resumption of full training. We used interrupted time series analyses to examine the association between fixed and dynamic ergometer testing on rowers’ injury rates. Time lost from illness was also recorded.

Results

All 153 rowers selected over eight seasons were observed for 48 611 AD. 270 injuries occurred with an incidence of 4.1–6.4 injuries per 1000 AD. Training days lost totalled 4522 (9.2% AD). The most frequent area injured was the lumbar region (84 cases, 1.7% AD) but the greatest burden was from chest wall injuries (64 cases, 2.6% AD.) Overuse injuries (n=224, 83%) were more frequent than acute injuries (n=42, 15%). The most common activity at the time of injury was on-water rowing training (n=191, 68). Female rowers were at 1.4 times the relative risk of chest wall injuries than male rowers; they had half the relative risk of lumbar injuries of male rowers. The implementation of a dynamic ergometers testing policy (Concept II on sliders) was positively associated with a lower incidence and burden of low back injury compared with fixed ergometers (Concept II). Illness accounted for the greatest number of case presentations (128, 32.2% cases, 1.2% AD).

Conclusions

Chest wall and lumbar injuries caused training time loss. Policy decisions regarding ergometer testing modality were associated with lumbar injury rates. As in many sports, illness burden has been under-recognised in elite Australian rowers.

Physical activity-related injuries of college students in southern China: A 1-year prospective study

This prospective study was to describe the incidence and characteristics of physical activity-related injuries (PARI) among college students in southern China. Online questionnaires and telephone interviews were combined to investigate the physical activity (PA) participation and PARI occurrences every two weeks. Totally, 84 college students (men: 49; women: 35) with a mean age of 19.4 years completed the entire 1-year follow-up. Overall, 14250.3 PA exposure hours were collected and 36 PARI episodes were reported by 26 students, with an injury incidence density of 2.53 injuries per 1000 PA exposure hours and an injury risk of 0.43 injuries/student/year. July to September accounted for a highest proportion of injuries and half of the injuries happened in the evening. The majority of injuries occurred outdoors, happened in non-contact activities, were acute and involved the lower limbs, with sprains and strains being the primary injury types. Of all injuries, 80.6% resulted in PA withdrawal immediately and 58.3% led to absence from the next planned PA. No significant difference was found between men and women. This study reveals the problem of PARI among college students, which provides the direction for the prevention of PARI in this population.

The epidemiology of injuries in adult amateur rowers: A cross-sectional study

OBJECTIVES

To investigate the prevalence, nature and factors associated with injury among adult amateur rowers.

DESIGN

Retrospective cross-sectional study.

SETTING

UK-based amateur rowing clubs.

PARTICIPANTS

160 amateur rowers.

MAIN OUTCOME MEASURES

Frequency, type, location, severity and rowing-related factors associated with injury.

RESULTS

Injury rate was 5.7 per 1000 sessions, with no effect of sex (χ² = 0.195, P = 0.659) or weight class (χ² = 0.800, P = 0.371). The lower-back demonstrated an epidemiological incidence proportion (IP) of 0.39 (95%CI = 0.33 to 0.46). The IP for water- and land-based training was 0.39 (95%CI = 0.31 to 0.47) and 0.57 (95%CI = 0.49 to 0.65), respectively. IP was highest between January and March (0.13-0.15), whilst time loss was 0.49 (95%CI = 0.42-0.57). The IP for 'overuse' and 'traumatic' injuries was 0.71 (95%CI = 0.65 to 0.78) and 0.22 (95%CI = 0.16 to 0.27), respectively. Training volume was positively associated with injury rate (r = 0.418, P < 0.001).

CONCLUSIONS

Injury rates appear higher among amateur rowers with the most common injury site being the lower-back. Our results suggest several contextual factors influence injury risk including seasonal phase, training type and training volume.

The relationship between single-limb squat and jump-cut kinematics

No objective criteria exist for progressing athletes into cutting manoeuvres following ACL reconstruction (ACLR). The purpose of this study was to evaluate the relationship between a jump-cut task (JC) and the single-limb squat (SLS) in both ACLR and healthy controls. Case-control, laboratory based. Twenty-three participants with a history of ACLR (Age = 21 ± 3 years; Height = 174.5 ± 7.2 cm; Mass = 76.2 ± 9.9 kg) and 23 healthy controls participants (Age = 21 ± 3 years; Height = 173.8 ± 9.2 cm; Mass = 75.0 ± 10.5 kg) were included. Kinematics were collected bilaterally. Correlations between tasks were evaluated for kinematics. Independent sample t-tests were used to evaluate differences between groups for each dependent variable. Peak trunk rotation and medial knee displacement were strongly correlated (p < 0.001, r² = 0.63), between tasks. ACLR group performed SLS and JC tasks with less sagittal plane motion compared to healthy controls (p < 0.05). Lack of frontal and transverse plane control during SLS resulted in positions of increased lateral trunk flexion, hip adduction, and medial knee displacement during JC. The SLS may be considered for use as a clinical predictor of JC during rehabilitation following ACLR.

A hidden mismatch between experiences of young athletes with overuse injuries of the wrist and sports physicians' perceptions: a focus group study

BACKGROUND

Although overuse wrist injuries can have serious consequences, young athletes often do not immediately report their injury to a physician. This qualitative study aimed to identify symptoms and limitations related to overuse wrist injuries that young athletes consider important and to compare those with sports physicians' opinions, in order to improve the diagnostic process for early identification of overuse wrist injuries.

METHODS

Twenty-one athletes aged 13-25 years in wrist-loading sports (gymnastics, tennis, judo, field hockey, volleyball and rowing) with a (previous) overuse wrist injury were included. In five focus groups, participants discussed important signals and limitations of their injury, as well as a list of relevant items previously composed by sports physicians. Data were grouped into themes and (sub)categories and subsequently coded.

RESULTS

Of the resulting 224 signals and 80 limitations, respectively 81 and 20 were labelled important. Athletes considered both pain and limitations during daily life activities important indicators of overuse wrist injury, as well as long pain duration, acute onset of pain, and accompanying symptoms like swelling, cracking and discoloration. All of the sports physicians' items were also considered important by the athletes, but sport-related pain and limitations were regarded by many athletes as a natural part of their sport.

CONCLUSIONS

Discrepancies exist between the opinions of young athletes and sports physicians on sport-related pain reporting and competing regardless of pain or limitations. Although clinicians may be inclined to focus on these aspects, they are advised to also inquire specifically about limitations and pain during daily life activities in young athletes with overuse wrist injuries.

Elite Rowers Demonstrate Consistent Patterns of Hip Cartilage Damage Compared With Matched Controls: A T2* Mapping Study

BACKGROUND

Rowing exposes the femoral head and acetabulum to high levels of repetitive abutment motion and axial loading that may put elite athletes at an increased risk for developing early hip osteoarthritis.

QUESTIONS/PURPOSES

Do elite rowers demonstrate characteristic hip cartilage lesions on T2 MRI sequences compared with asymptomatic individuals who do not row?

METHODS

This study included 20 asymptomatic rowers (mean age, 23 ± 3 years; nine females, 11 males) who had a minimum of 5 years of intensive (≥ 12 hours/week) training. The recruiting of the rowers took place from the central German federal rowing base, which has inherent intense training and selection requirements to declare these athletes as "elite rowers." We investigated one hip per study participant. MRI was performed on a 3-T scanner. The protocol included standard sequences, a double-echo steady-state sequence, and a multiecho data image combination sequence with inline T2 calculation (= the decay of transverse magnetization arising from molecular interactions [T2] and inhomogeneities in the magnetic field resulting from tissue susceptibility-induced field distortions and variations in the magnet itself), which detects changes in water content and the disruption of collagen structure. Although extrinsic and intrinsic influences on the T2 values including diurnal effects, MR technic-derived variations, and anatomic-related regional disparities need to be taken into account, low T2 values well below 20 ms indicate cartilage degeneration. Cartilage was morphologically analyzed in the anterior, anterosuperior, superoanterior, superior, superoposterior, posterosuperior, and posterior regions of the hip and graded as follows: Grade 0 = normal; Grade 1 = signal changes; Grade 2 = cartilage abrasion; Grade 3 = cartilage loss. Labrum was classified as follows: Grade 0 = normal; Grade 1 = partial tear; Grade 2 = full-thickness tear; Grade 3 = labrum degeneration. The T2 measurement was done through a region of interest analysis. For reliability assessment, morphologic evaluation and T2 measurement were performed by two observers while one observer repeated his analysis with a time interval > 2 weeks. Intra- and interobserver reliability was determined using κ analysis and intraclass correlation coefficients. Control T2 data were derived from a previous study on 15 hips in 15 asymptomatic volunteers of similar ages (seven males and eight females) who were not competitive rowers with similar MR hardware and imaging sequences.

RESULTS

Compared with the control group of asymptomatic volunteers who were not competitive rowers, we noted a high level of labrum and cartilage degeneration in the cohort of elite rowers. In the group of elite rowers, cartilage degeneration was noted in all hips. Regarding the acetabular cartilage, 271 zones could be evaluated. Of those, 44% (120 of 271) were graded normal, 6% (15 of 271) revealed signal alteration, 45% (122 of 271) demonstrated cartilage abrasion, and 5% (14 of 271) were noted to have full-thickness cartilage loss. Morphologic cartilage degeneration in the femoral head was less frequent. T2 values were lower than the control hips in all zones except for the posterior central acetabular zone (global T2 acetabular: 20 ± 6 ms, range, 9-36 ms, 95% confidence interval [CI], 19-21 ms versus 25 ± 5 ms, range, 14-44 ms, 95% CI, 24-25 ms, p < 0.001; global T2 femoral: 23 ± 7 ms, range, 9-38 ms, 95% CI, 22-24 ms versus 27 ± 5 ms, range, 17-45 ms, 95% CI, 26-28 ms, p < 0.001). The difference in T2 between the two study groups was superior in the peripheral zone of the anterosuperior region (16 ± 3 ms; range, 10-22 ms, 95% CI, 15-18 ms versus 26 ms ± 5 ms, range, 18-38 ms, 95% CI, 24-29 ms, p < 0.001).

CONCLUSIONS

We found signs of hip cartilage degeneration to a much greater degree in elite rowers than in asymptomatic controls. Although causation cannot be inferred, this is concerning, and future investigations including controlled longitudinal studies both on elite and nonelite athletes with sufficient cohort size are warranted to clarify our findings.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The effect of landing type on kinematics and kinetics during single-leg landings

Landing research attempts to simulate sport activities; however, movements performed pre- or post-landing may alter landing mechanics and injury risk. Therefore, this study compared lower extremity biomechanics of single-leg drop landings, drop jump (DJ) and countermovement jump (CMJ) landings as well as sex-related differences. A total of 25 recreational athletes (11 females) performed landings from 80% maximum jump height with impact forces, kinematics and joint moments measured during each landing. Altered kinematic and kinetic variables were revealed when a jump was performed pre- or post-landing. CMJ landings were generally performed with a more extended lower extremity at ground contact, less hip and knee motion in the frontal and transverse planes and larger joint moments compared to other landings (p < 0.01). The DJ landings demonstrated greater joint flexion and large frontal and transverse plane motion, paired with decreased impact forces and joint moments (p < 0.05). Across all landings, males displayed larger impact forces and joint moments (p < 0.01), and females demonstrated frontal plane kinematics associated with increased injury risk (p < 0.05). These findings suggest that activities surrounding the landing directly impact landing mechanics and overall risk. Therefore, matching landing type to sport-specific activities increases the efficacy of assessing injury risk during training or rehabilitation programmes.

Effects of deceleration-focused exercise strategies on shoulder range of motion and throwing velocity in baseball and softball athletes

This study examined the effects of deceleration-focused exercises on shoulder range of motion and throwing velocity in both softball and baseball players. Volunteers included 28 Division III William Paterson University baseball and softball athletes (18 females and 10 males), who were evenly distributed across two groups both undertaking 14 sessions of either resistance band or handheld medicine ball exercises (band vs. ball group). A pre-test and post-test measured participants' best active internal/external shoulder rotation and best throwing velocity at a target 40 ft away. A two-tailed, independent t-test showed no significant differences in velocity, internal rotation or external rotation (p < 0.01) between the band and ball groups. However, the average change in velocity in the ball group was double that of the band group (1.50 ± 2.06 m/s versus 0.73 ± 2.24 m/s). For change in both internal and external rotation the band group (2.86 ± 5.27° and 3.29 ± 3.87°, respectively) was greater than the ball mean (1.93° ± 3.32° and 1.29 ± 6.52°, respectively). These findings suggest that overhead athletes aiming to increase throwing velocity can benefit from performing deceleration training with weighted balls whereas resistance bands appear to improve shoulder rotation.

Sport injuries in international masters rowers: a cross-sectional study

Methods

A cross-sectional study was conducted among 743 masters rowers who participated in the 34th International Federation of Rowing Associations (Fédération Internationale des Sociétés d’Aviron, FISA) World Rowing Masters Regatta held in Zagreb, September 2-9, 2007. A rowing-specific questionnaire was used, followed by an interview about the injuries sustained during the 12-month period before the competition.

Results

The mean injury rate per year was 0.48 injuries/masters rower (2.25 injuries/1000 training sessions/rower). The majority of injuries were chronic injuries (the ratio of acute to chronic injuries was 1:1.7), and did not lead to the loss of training/competition time. Of all acute injuries, 49.6% were acquired during rowing-specific training, 43.7% during cross-training, and 6.7% in the gym. The most commonly affected region was the low back (32.6%), followed by the knee (14.2%), shoulder/upper arm, and elbow (10.6% each).

Conclusion

International masters rowers sustained predominantly chronic injuries of low severity, and the most commonly injured region was the low back. The mean injury rate per rower per year was lower than the rates previously reported for juniors and seniors.

Influence of biomechanical models on joint kinematics and kinetics in baseball pitching

In baseball pitching, biomechanical parameters have been linked to ball velocity and potential injury risk. However, although the features of a biomechanical model have a significant influence on the kinematics and kinetics of a motion, this influence have not been assessed for pitching. The aim of this study was to evaluate the choice of the trunk and shoulder features, by comparing two models using the same input. The models differed in thoraco-humeral joint definition (moving or fixed with the thorax), joint centre estimation, values of the inertial parameters and computational framework. One professional pitcher participated in the study. We found that the different features of the biomechanical models have a substantial influence on the kinematics and kinetics of the pitchers. With a fixed thoraco-humeral joint the peak average thorax angular velocity was delayed and underestimated by 17% and the shoulder internal rotation velocity was overestimated by 7%. The use of a thoraco-humeral joint fixed to the thorax will lead to an overestimation of the rotational power at the shoulder and will neglect the power produced by the forward and upward translation of the shoulder girdle. These findings have direct implications for the interpretation of shoulder muscle contributions to the pitch.

Implications of anticoagulants and gender on cell counts and growth factor concentration in platelet-rich plasma and platelet-rich gel supernatants from rabbits

Objectives: Our objectives were as follows: 1) to validate a protocol for producing rabbit platelet-rich plasma (PRP); 2) to determine the influence of two anticoagulants, sodium citrate and acid-citrate-dextrose solution A, and gender on cell count in PRP and growth factor concentration in pure platelet-rich gel supernatants; 3) to correlate the variables evaluated.

Methods: Whole blood from 18 New Zealand rabbits (9 males and 9 females) was obtained with sodium citrate and acid- citrate-dextrose solution A for processing PRP fractions (A and B), which were evaluated for haematology. The PRP fractions were either activated with calcium gluconate or lysated with a detergent. The concentrations of transforming growth factor beta 1 and platelet-derived growth factor BB were assayed by ELISA.

Results: The sodium citrate PRP-B had significantly higher counts of platelets in comparison to PRP-A and whole blood obtained with the same anticoagulant and the homologous acid-citrate-dextrose solution A PRP fraction. The sodium citrate PRP-A had a significantly higher count of leukocytes compared to the homologous acid-citrate-dextrose solution A fraction. All the PRP fractions had a significant leuko-reduction when compared to whole blood. The sodium citrate PRP-A fraction from female rabbits had significantly lower platelet counts and significantly higher leukocyte counts than the same acid-citrate-dextrose solution A fraction. Growth factor concentration was not affected by the type of anticoagulant or gender.

Clinical significance: The type of anticoagulant and gender affected the cell counts in PRP, but they did not influence the growth factor concentration. More complete rabbit PRP studies should be performed before evaluating this type of substance in models of disease.

Textured insoles affect the plantar pressure distribution while elite rowers perform on an indoor rowing machine

INTRODUCTION

During rowing, foot positioning on the foot stretcher is critical to optimise muscle force transmission and boat propulsion. Following the beneficial effects of textured insoles on gait and balance, this study aims at investigating whether passive stimulation of foot mechanoreceptors induced by these insoles may contribute to improving foot loading pattern and symmetry during indoor rowing.

METHODS

Eleven elite rowers were assessed during controlled training on a standard rowing machine while wearing control, low-density or high-density textured insoles. Plantar pressure and knee and trunk kinematics were measured; performance data were recorded from the machine. Insole effect on kinematic parameters, peak and average values of foot force, contact area and position of centre of pressure was assessed with ANOVA and Bonferroni correction for pair-wise comparisons.

RESULTS

A main effect was observed for force and contact area, with the high-density insoles providing greatest values (P<0.035). No interaction was observed between side and insole (P>0.190), even though symmetry was higher with high-density insoles. Kinematics (P = 0.800) and rowing performance were not affected by insole type; a consistent though not statistically significant increase in mean travelled distance was observed for denser insoles (P>0.21).

CONCLUSION

The high-density textured insoles affected foot loading distribution during indoor rowing. Rowers applied greater foot force and over a greater foot stretcher area with the high-density than the low-density and control insoles. These findings and the methodology applied may be relevant for the understanding and monitoring of rowing performance.

Low Back Pain in Young Basketball and Floorball Players

OBJECTIVE

The aim of the study was to investigate the prevalence and risk factors of low back pain (LBP) in young female and male basketball and floorball players.

DESIGN

Cross-sectional study.

SETTING

Nine basketball teams and 9 floorball teams from Tampere city district, Finland.

PARTICIPANTS

Four hundred one young female and male players (mean age: 15.8 ± 1.9 years).

ASSESSMENT OF RISK FACTORS

Age, gender, sport, and family history of musculoskeletal disorders were assessed as risk factors for LBP. Adjustment was made on team level to avoid random effects associated with a team.

MAIN OUTCOME MEASURES

Information of players' background factors and LBP episodes was collected by a structured questionnaire.

RESULTS

Forty-four percentage of the basketball players and 62% of floorball players had suffered from LBP during the previous 12 months. Prevalence of LBP during the previous year was significantly higher among floorball players (P = 0.001). In both sports, prevalence of pain symptoms was the highest during the competitive playing season. Family history of musculoskeletal disorders [OR (odds ratio), 2.02, 95% confidence interval (CI), 1.22-3.34] and higher age (OR, 1.22, 95% CI, 1.05-1.41) were associated with LBP in players.

CONCLUSIONS

The study attested that LBP is a relatively common complaint in young team sport players. Targeted measures to examine causes, risk factors, and prevention of LBP in youth sports are needed.

Influence of foot-stretcher height on rowing technique and performance

Strength, technique, and coordination are crucial to rowing performance, but external interventions such as foot-stretcher set-up can fine-tune technique and optimise power output. For the same resultant force, raising the height of foot-stretchers on a rowing ergometer theoretically alters the orientation of the resultant force vector in favour of the horizontal component. This study modified foot-stretcher heights and examined their instantaneous effect on foot forces and rowing technique. Ten male participants rowed at four foot-stretcher heights on an ergometer that measured handle force, stroke length, and vertical and horizontal foot forces. Rowers were instrumented with motion sensors to measure ankle, knee, hip, and lumbar-pelvic kinematics. Key resultant effects of increased foot-stretcher heights included progressive reductions in horizontal foot force, stroke length, and pelvis range of motion. Raising foot-stretcher height did not increase the horizontal component of foot force as previously speculated. The reduced ability to anteriorly rotate the pelvis at the front of the stroke may be a key obstacle in gaining benefits from raised foot-stretcher heights. This study shows that small changes in athlete set-up can influence ergometer rowing technique, and rowers must individually fine-tune their foot-stretcher height to optimise power transfer through the rowing stroke on an ergometer.

High School Rowing Injuries: National Athletic Treatment, Injury and Outcomes Network (NATION)

CONTEXT

Data on high school (HS) rowing injuries are lacking.

OBJECTIVE

To describe the epidemiology of HS boys' and girls' rowing injuries during the 2011-2012 through 2013-2014 academic years.

DESIGN

Descriptive epidemiology study.

SETTING

Injury and exposure data from 8 and 11 boys' and girls' rowing programs providing 13 and 17 team-seasons of data, respectively.

PATIENTS OR OTHER PARTICIPANTS

High school boys' and girls' varsity rowing student-athletes.

INTERVENTION(S)

High school rowing data from the National Athletic Treatment, Injury and Outcomes Network.

MAIN OUTCOME MEASURE(S)

Injury rates and rate ratios were reported with 95% confidence intervals (CIs).

RESULTS

In HS boys' and girls' rowing, 59 and 190 injuries were reported, respectively, for rates of 2.39/1000 athlete-exposures (95% CI = 1.78, 3.00) and 8.60/1000 athlete-exposures (95% CI = 7.38, 9.82). The girls' rowing injury rate was 3.60 times that of boys' (95% CI = 2.69, 4.82).

CONCLUSIONS

These findings suggest a higher injury rate among HS female rowers than HS male rowers. Additional research exploring reasons for the sex difference is warranted.

Epidemiology of overuse injuries among high-school athletes in the United States

OBJECTIVE

To examine high school overuse injury rates and patterns by sex and sport.

STUDY DESIGN

High school athletes participating in the High School Reporting Information Online study were examined in a descriptive epidemiologic study. Overuse injury data for the 2006/2007-2011/2012 academic years collected via High School Reporting Information Online from a large national sample of US high schools where certified athletic trainers completed detailed injury reports were evaluated.

RESULTS

From 2006/2007 to 2011/2012, a total of 2834 overuse injuries were reported during 18 889 141 athletic exposures (1.50 per 10 000 athletic exposures). Girls had greater rates of overuse injury (1.88) than boys (1.26) (rate ratio 1.50, 95% CI 1.39-1.61). The greatest rates were in girls' track and field (3.82) and girls' field hockey (2.93). Overuse injuries represented 7.7% of all injuries, ranging from a low of 1.4% of all boys' ice hockey injuries to a high of 55.7% of all boys' swimming and diving injuries. Overall, overuse injuries were evenly distributed across athletes in each year of high school (freshman, 25.6%; sophomore, 25.3%; junior, 24.9%; senior, 24.3%). However, there were distinct differences by sex. The most frequent site of injury was the lower leg (21.8%). Injuries most frequently resulted in time loss of less than 1 week (50.0%), with only 7.6% resulting in time loss greater than 3 weeks.

CONCLUSIONS

Overuse injury patterns differed by sex and sport. A better understanding of overuse injury patterns and criteria for return to play may help direct preventative measures and injury management.