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Prevention of rib stress injury in rowers. What do we know and where do we need to go?
Abstract
Background: Rib pain is a common complaint among rowers and can lead to significant time loss from sport. Recent literature has emerged regarding rib stress injury (RSI) prevention and management. The aim of the present review was to update current knowledge regarding risk factors and injury mechanisms of RSI in rowers and suggest strategies for clinical application of this emerging evidence as well as suggest future areas of study. Material and methods: Existing literature on RSI risk factors and mechanisms, and on research methodology in overuse injuries in general, was reviewed. Results: Search results revealed several intrinsic and extrinsic factors related to rib stress and its response, including detrimental muscle loading of the ribs, low energy availability (LEA) and the potential influence of ergometer rowing. Conclusions: Emerging issues regarding risk factors and mechanisms in RSI may help inform clinical application and future research. There remains a pressing need for further studies regarding RSI aetiology and epidemiology to guide effective prevention strategies, particularly in subgroups such as para rowers and non-elites.
... When the fixed ergometer is placed on slides, in order to convert it to dynamic, the mass of the ergometer is free to move. 52 Increased peak force/power production at the handle in fixed ergometers has consistently been observed when compared with dynamic ergometers in investigations of rowing at identical exercise intensities between 70% and 100% of 2000 m race pace. [49][50][51] This could be hypothesised to affect the overall loading of the rower including the forces acting on the lumbar spine. ...
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.
Rib bone stress injury (BSI) occurs most commonly in athletes performing repetitive upper body movements and results in significant time lost from training and competition. These injuries are seen in rowing, baseball, swimming, golf, weightlifting, and other throwing sports. Similar to BSI at other anatomical locations, a rib BSI often results from multiple factors including both thoracic/upper extremity biomechanics and metabolic factors affecting bone health. Although some rib BSIs are easier to detect, other injuries may present with vague rib or shoulder pain that can be misdiagnosed and result in delayed management. Our narrative review describes biomechanical and other health factors that contribute to a rib BSI. We describe an approach to evaluation including diagnostic imaging and management strategies to guide return to sport. This includes discussion of prevention/mitigation of underlying modifiable factors, including training load monitoring, addressing biomechanical factors, and correction of nutritional/hormonal deficiencies.
Aim
To describe the demographics, frequency, location, imaging modality and clinician-identified factors of rib stress injury in a cohort of elite rowers over the Rio Olympiad (2012–2016).
Methods
Analysis of prospectively recorded medical records for the Australian Rowing Team in 2013–2015 and the combined Australian Rowing Team and Olympic Shadow Squad in 2016, examining all rib stress injuries.
Results
19 rib stress injuries (12 reactions and 7 fractures) were identified among a cohort of 151 athletes and included 12 female and 7 male cases, 11 open weight, 8 lightweight, 12 scull and 7 sweep cases. The most common locations of injury identified by imaging, were the mid-axillary line and rib 6. Period prevalence varied from 4% to 15.4% and incidence ranged from 0.27 to 0.13 per 1000 athlete days. There were no significant differences in prevalence by sex, sweep versus scull or weight class. There was a statistically significant increase in incidence in the pre-Olympic year (2015, p<0.001). MRI was the most commonly used modality for diagnosis. Stress fracture resulted in median 69 (IQR 56–157) and bone stress reaction resulted in 57 (IQR 45–78) days lost to full on water training.
Conclusions
In our 4-year report of rib stress injury in elite rowing athletes, period prevalence was consistent with previous reports and time lost (median ~10 weeks) was greater than previously published literature. Rib stress injury limits training and performance in elite rowers and MRI should be considered as a first line investigation.
Objectives:
To examine the epidemiology of bone stress injuries in an elite sports institute.
Design:
Retrospective cohort study at the Australian Institute of Sport.
Methods:
A retrospective analysis of the clinical records contained within the Australian Institute of Sport Athlete Management System electronic database was performed. Records with Orchard Sports Injury Classification System codes relating to bone stress injuries and stress fractures were reviewed and descriptive statistics relating to sport, site of injury, athlete age, sex and activity were analysed.
Results:
In the three-year period January 2014-2017, 11,942 injuries were recorded across 48 sports. 181 bone stress injuries (0.15% of all injuries) were recorded across 16 sports. BSIs in the foot and lumbar spine were the most common accounting for 30% and 23% of all the reported BSIs respectively. Gymnasts had a high frequency of lumbar spine stress injuries (n=24, 51%) and rowers had a high frequency of rib stress injuries (n=22, 88%). The most common location for stress injuries, equally distributed across a variety of sports, were in the foot (n=54, 30%). Female athletes recorded more BSIs than males.
Conclusion:
Across a three-year period, 0.15% of injuries were related to bone stress injuries. Almost double the cases were recorded in female athletes. Sport specific injury sites were observed in the dataset.
Although traditionally seen as a sport for elite schools and colleges, rowing is a founding Olympic event and is increasingly enjoyed by people of all ages and abilities. The sport’s rapidly changing demographics shows significant growth in masters (age 27 years and above) and para-rowing populations. It has further expanded beyond its traditional flatwater format to include the discipline of open-water or coastal rowing, and an increased focus on indoor rowing. Rowing-specific injury research has similarly increased over the last decade since our last review, revealing areas of improved understanding in pre-participation screening, training load, emerging concepts surrounding back and rib injury, and relative energy deficiency in sport. Through a better understanding of the nature of the sport and mechanisms of injury, physicians and other healthcare providers will be better equipped to treat and prevent injuries in rowers.
Protecting the health of the athlete is a goal of the International Olympic Committee (IOC). The IOC convened an expert panel to update the 2005 IOC Consensus Statement on the Female Athlete Triad. This Consensus Statement replaces the previous and provides guidelines to guide risk assessment, treatment and return-to-play decisions. The IOC expert working group introduces a broader, more comprehensive term for the condition previously known as 'Female Athlete Triad'. The term 'Relative Energy Deficiency in Sport' (RED-S), points to the complexity involved and the fact that male athletes are also affected. The syndrome of RED-S refers to impaired physiological function including, but not limited to, metabolic rate, menstrual function, bone health, immunity, protein synthesis, cardiovascular health caused by relative energy deficiency. The cause of this syndrome is energy deficiency relative to the balance between dietary energy intake and energy expenditure required for health and activities of daily living, growth and sporting activities. Psychological consequences can either precede RED-S or be the result of RED-S. The clinical phenomenon is not a 'triad' of the three entities of energy availability, menstrual function and bone health, but rather a syndrome that affects many aspects of physiological function, health and athletic performance. This Consensus Statement also recommends practical clinical models for the management of affected athletes. The 'Sport Risk Assessment and Return to Play Model' categorises the syndrome into three groups and translates these classifications into clinical recommendations.
Low energy availability (EA) in female athletes with or without an eating disorder (ED) increases the risk of oligomenorrhoea/functional hypothalamic amenorrhoea and impaired bone health, a syndrome called the female athlete triad (Triad). There are validated psychometric instruments developed to detect disordered eating behaviour (DE), but no validated screening tool to detect persistent low EA and Triad conditions, with or without DE/ED, is available.
The aim of this observational study was to develop and test a screening tool designed to identify female athletes at risk for the Triad.
Female athletes (n=84) with 18-39 years of age and training ≥5 times/week filled out the Low Energy Availability in Females Questionnaire (LEAF-Q), which comprised questions regarding injuries and gastrointestinal and reproductive function. Reliability and internal consistency were evaluated in a subsample of female dancers and endurance athletes (n=37). Discriminant as well as concurrent validity was evaluated by testing self-reported data against measured current EA, menstrual function and bone health in endurance athletes from sports such as long distance running and triathlon (n=45).
The 25-item LEAF-Q produced an acceptable sensitivity (78%) and specificity (90%) in order to correctly classify current EA and/or reproductive function and/or bone health.
The LEAF-Q is brief and easy to administer, and relevant as a complement to existing validated DE screening instruments, when screening female athletes at risk for the Triad, in order to enable early detection and intervention.
To determine bone mineral density (BMD) and the associations among BMD, menstrual history, disordered eating (DE), training history, intentional weight loss (IWL) and rib pain for the first time in female lightweight rowers.
9 lightweight rowing clubs, UK.
29 Caucasian female lightweight rowers volunteered. 21 (12 active, 9 retired) completed the study. Inclusion criteria: female lightweight rowers aged over 18 years. Exclusion criteria: participants with a history of bone disease, used medications known to influence BMD or if they were pregnant, lactating or postmenopausal.
Dual-energy X-ray absorptiometry measured total body (TB) composition and BMD at the spine, femoral neck (FN), radius and TB. DE, oligomenorrhoea/amenorrhoea years; rib pain and training history.
DE was reported in six of the rowers. The active with DE started rowing younger (p<0.05) than those without, and their amount of IWL was associated with Eating Attitudes Test-26 score (p<0.05). Some participants reported a history of oligomenorrhoea/amenorrhoea 17 (76%) and/or rib pain 7 (32%) with those with rib pain having lower spine and TB Z-scores (p<0.05) than those without. Those with oligomenorrhoea/amenorrhoea had lower spine Z-scores (p<0.01) than those without. Twelve participants had low BMD; three at spine; one at FN; and eight at radius. Thirteen per cent of mean total training hours (18.6±9.1 h/week) were spent strength training (2.4±2.2 h/week).
Upper body exercises incorporating multidimensional high peak bone strain were not reported and may need to be considered in their strength training to improve radial BMD. Results suggest IWL and high-level training at a young age increases the likelihood of DE and there may be a lack of quality nutritional support for these athletes. Thus, multidisciplinary sport science support should be offered at a young age and perhaps also to consider changing the weight rules to prevent the development of the Triad.
THIS STUDY USED SURFACE ELECTROMYOGRAPHY (SEMG) TO EXAMINE WHETHER THERE WERE DIFFERENCES IN HIP AND TRUNK MUSCLE ACTIVATION DURING THE ROWING CYCLE ON TWO OF THE MOST WIDELY USED AIR BRAKED ERGOMETERS: the Concept 2C and the Rowperfect. sEMG methods were used to record the muscle activity patterns from the right: m. Erector spinae (ES), m. Rectus Abdominus (RA), m. Rectus Femoris (RF) and m. Biceps Femoris (BF) for their contributions as agonist-antagonist pairs underlying hip and trunk extension/flexion. The sEMG activity patterns of these muscles were examined in six young male elite rowers completing a 2 minute set at a moderate training intensity (23 stroke·min(-1) and 1:47.500 m(-1) split time, 300W). The rowers closely maintained the required target pace through visual inspection of the standard LCD display of each ergometer. The measurements of duration of each rowing cycle and onset of each stroke during the test were recorded simultaneously with the sEMG activity through the additional instrumentation of a foot-pressure switch and handle accelerometry. There were no significant differences between the two ergometer designs in group means for: work rate (i.e., rowing speed and stroke rate), metabolic load as measured by mean heart rate, rowing cycle duration, or timing of the stroke in the cycle. 2-D motion analysis of hip and knee motion for the rowing cycle from the video footage taken during the test also revealed no significant differences in the joint range of motion between the ergometers. Ensemble average sEMG activity profiles based on 30+ strokes were obtained for each participant and normalised per 10% intervals of the cycle duration as well as for peak mean sEMG amplitude for each muscle. A repeated measures ANOVA on the sEMG activity per 10% interval for the four muscles contributing to hip and trunk motion during the rowing cycle revealed no significant differences between the Concept 2C and Rowperfect (F = 0.070, df = 1,5, p = 0.802). The outcome of this study suggests that the two different ergometer designs are equally useful for dry land training. Key PointsThe effects of endurance training on HR recovery after exercise and cardiac ANS modulation were investigated in female marathon runners by comparing with untrained controls.Time and frequency domain analysis of HRV was used to investigate cardiac ANS modulation.As compared with untrained controls, the female marathon runners showed faster HR recovery after exercise, which should result from their higher levels of HRV, higher aerobic capacity and exaggerated blood pressure response to exercise.
Subclinical ovulatory disturbances (anovulation or short luteal phases within normal-length menstrual cycles) indicate lower progesterone-to-estrogen levels. Given that progesterone plays a bone formation role, subclinical ovulatory disturbances may be associated with bone loss or less than expected bone gain. Our purpose was to perform a meta-analysis of prospective studies in healthy premenopausal women to determine the overall relationship of subclinical ovulatory disturbances to change in bone mineral density. Two reviewers independently identified from serial literature searches 6 studies meeting inclusion criteria: a 2-year study in 114 young adult women, 2006-2009, Vancouver, Canada; a 2-year study in 189 premenopausal women, 2000-2005, Toronto, Canada; a single-cycle study in 14 young women, 1996-1997, Melbourne, Australia; an 18-month study in 53 women, 1990-1995, Santa Clara, California; a 4-year study in 27 women, 1988-1995, Vancouver, Canada; and a 1-year study in 66 women, 1985-1988, Vancouver, Canada. This meta-analysis included a combined sample size of 473 observations in 436 premenopausal women studied over 1-4 years and aged 14-47 years. The percentage of women with ovulatory disturbances varied significantly from 13% to 82%. Women with more frequent ovulatory disturbances had more negative percentage changes in spine bone mineral density (weighted mean difference = -0.86; P = 0.040) for random-effects analysis. There was significant heterogeneity among these 6 studies (I(2) = 80%). In summary, these data show that regularly menstruating women with more frequent ovulatory disturbances experience more negative changes in bone (approximately -0.9% per year). These cycles with silent estrogen/progesterone imbalance may be clinically important.
Biomechanical and physiological responses to rowing 1000 m at a power output equivalent to a 2000 m race were compared in 34 collegiate rowers (17 women, 17 men) rowing on a stationary and dynamic Concept 2 ergometer. Stroke ratio, peak handle force, rate of force development, impulse, and respiratory exchange ratio decreased by 15.7, 14.8, 10.9, 10.2 and 1.9%, respectively, on the dynamic ergometer. In contrast, percent time to peak force and stroke rate increased by 10.5 and 12.6%, respectively, during dynamic ergometry; the changes in stroke rate and impulse were greater for men than women. Last, VO2 was 5.1% higher and efficiency 5. 3% lower on the dynamic ergometer for men. Collegiate rowers used higher stoke rates and lower peak stroke forces to achieve a similar power output while rowing at race pace on the dynamic ergometer, which may have increased the cardiopulmonary demand and possibly reduced force production in the primary movers. Differences were more pronounced in males than females; this dichotomy may be more due to dynamic ergometer familiarity than sex. Key pointsWhen rowing at a constant power output, all rowers used higher stroke rates and lower stroke forces on the Concept 2 Dynamic ergometer as compared to the Concept 2 Stationary ergometer.When rowing at a constant power output, cardiopulmonary demand was higher for all rowers, as measured by heart rate, on the Concept 2 Dynamic ergometer as compared to the Concept 2 Stationary ergometer.When rowing at a constant power output, efficiency was lower for male rowers on the Concept 2 Dynamic ergometer as compared to the Concept 2 Stationary ergometer.
Background Little information exists on the illness and injury patterns of athletes preparing for the Olympic and Paralympic Games. Among the possible explanations for the current lack of knowledge are the methodological challenges faced in conducting prospective studies of large, heterogeneous groups of athletes, particularly when overuse injuries and illnesses are of concern.
Objective To describe a new surveillance method that is capable of recording all types of health problems and to use it to study the illness and injury patterns of Norwegian athletes preparing for the 2012 Olympic and Paralympic Games.
Methods A total of 142 athletes were monitored over a 40-week period using a weekly online questionnaire on health problems. Team medical personnel were used to classify and diagnose all reported complaints.
Results A total of 617 health problems were registered during the project, including 329 illnesses and 288 injuries. At any given time, 36% of athletes had health problems (95% CI 34% to 38%) and 15% of athletes (95% CI 14% to 16%) had substantial problems, defined as those leading to moderate or severe reductions in sports performance or participation, or time loss. Overuse injuries represented 49% of the total burden of health problems, measured as the cumulative severity score, compared to illness (36%) and acute injuries (13%).
Conclusions The new method was sensitive and valid in documenting the pattern of acute injuries, overuse injuries and illnesses in a large, heterogeneous group of athletes preparing for the Olympic and Paralympic Games.
Background:
Current methods for injury registration in sports injury epidemiology studies may substantially underestimate the true burden of overuse injuries due to a reliance on time-loss injury definitions.
Objective:
To develop and validate a new method for the registration of overuse injuries in sports.
Methods:
A new method, including a new overuse injury questionnaire, was developed and validated in a 13-week prospective study of injuries among 313 athletes from five different sports, cross-country skiing, floorball, handball, road cycling and volleyball. All athletes completed a questionnaire by email each week to register problems in the knee, lower back and shoulder. Standard injury registration methods were also used to record all time-loss injuries that occurred during the study period.
Results:
The new method recorded 419 overuse problems in the knee, lower back and shoulder during the 3-month-study period. Of these, 142 were classified as substantial overuse problems, defined as those leading to moderate or severe reductions in sports performance or participation, or time loss. Each week, an average of 39% of athletes reported having overuse problems and 13% reported having substantial problems. In contrast, standard methods of injury registration registered only 40 overuse injuries located in the same anatomical areas, the majority of which were of minimal or mild severity.
Conclusion:
Standard injury surveillance methods only capture a small percentage of the overuse problems affecting the athletes, largely because few problems led to time loss from training or competition. The new method captured a more complete and nuanced picture of the burden of overuse injuries in this cohort.
Rowing is one of the original modern Olympic sports and was one of the most popular spectator sports in the United States. Its popularity has been increasing since the enactment of Title IX. The injury patterns in this sport are unique because of the stress applied during the rowing stroke.
This review summarizes the existing literature describing the biomechanics of the rowing stroke and rowing-related injury patterns. Data were obtained from previously published peer-reviewed literature through a search of the entire PubMed database (up to December, 2011) as well as from textbook chapters and rowing coaching manuals.
Rowing injuries are primarily overuse related. The knee, lumbar spine, and ribs are most commonly affected. The injury incidence is directly related to the volume of training and technique.
Familiarity of the injury patterns and the biomechanical forces affecting the rowing athlete will aid in prompt diagnosis and appropriate management.
Adaptive rowing is rowing or sculling for rowers with a physical disability. It debuted at the Paralympic Games in 2008. In order to ensure an equitable playing field, rowers with similar levels of physical function and disability are classified into different sport classes for competition. Rowers with an inability to use a sliding seat and impaired trunk function resulting in an inability to perform trunk forward and backward lean via hip flexion/extension are assigned to the Arms and Shoulders (AS) class. AS rowers have to use a chest strap set immediately below the chest in order to localize any trunk movement in AS class. Conditions created by adaptations of rowing equipment and technique within the AS class create unique stresses on the upper thoracic region. The following case report demonstrates how etiology and management of a rib stress fracture in an AS rower differs in comparison to able-body rowers. Of significant importance were the limitations imposed on the rower's ability to maintain rowing-specific fitness, due to the nature of the rib stress fracture and requirement to decrease force transmission through the ribs for several weeks. The rower's gradual return to full training was further impacted by obligatory use of the chest strap, which directly applied pressure over the injured area. Protective orthosis for the chest was designed and applied in order to dissipate pressure of the chest strap over the thorax during rowing (most importantly at the catch position) both on the ergometer and in the boat.
Rib stress fractures (RSFs) can have serious effects on rowing training and performance and accordingly represent an important topic for sports medicine practitioners. Therefore, the aim of this review is to outline the definition, epidemiology, mechanisms, intrinsic and extrinsic risk factors, injury management and injury prevention strategies for RSF in rowers. To this end, nine relevant books, 140 journal articles, the proceedings of five conferences and two unpublished presentations were reviewed after searches of electronic databases using the keywords 'rowing', 'rib', 'stress fracture', 'injury', 'mechanics' and 'kinetics'. The review showed that RSF is an incomplete fracture occurring from an imbalance between the rate of bone resorption and the rate of bone formation. RSF occurs in 8.1-16.4% of elite rowers, 2% of university rowers and 1% of junior elite rowers. Approximately 86% of rowing RSF cases with known locations occur in ribs four to eight, mostly along the anterolateral/lateral rib cage. Elite rowers are more likely to experience RSF than nonelite rowers. Injury occurrence is equal among sweep rowers and scullers, but the regional location of the injury differs. The mechanism of injury is multifactorial with numerous intrinsic and extrinsic risk factors contributing. Posterior-directed resultant forces arising from the forward directed force vector through the arms to the oar handle in combination with the force vector induced by the scapula retractors during mid-drive, or repetitive stress from the external obliques and rectus abdominis in the 'finish' position, may be responsible for RSF. Joint hypomobility, vertebral malalignment or low bone mineral density may be associated with RSF. Case studies have shown increased risk associated with amenorrhoea, low bone density or poor technique, in combination with increases in training volume. Training volume alone may have less effect on injury than other factors. Large differences in seat and handle velocity, sequential movement patterns, higher elbow-flexion to knee-extension strength ratios, higher seat-to-handle velocity during the initial drive, or higher shoulder angle excursion may result in RSF. Gearing may indirectly affect rib loading. Increased risk may be due to low calcium, low vitamin D, eating disorders, low testosterone or use of depot medroxyprogesterone injections. Injury management involves 1-2 weeks cessation of rowing with analgesic modalities followed by a slow return to rowing with low-impact intensity and modified pain-free training. Some evidence shows injury prevention strategies should focus on strengthening the serratus anterior, strengthening leg extensors, stretching the lumbar spine, increasing hip joint flexibility, reducing excessive protraction, training with ergometers on slides or floating-head ergometers, and calcium and vitamin D supplementation. Future research should focus on the epidemiology of RSF over 4-year Olympic cycles in elite rowers, the aetiology of the condition, and the effectiveness of RSF prevention strategies for injury incidence and performance in rowing.
The present study was designed to quantify the effect of power output on muscle coordination during rowing. Surface electromyographic (EMG) activity of 23 muscles and mechanical variables were recorded in eight untrained subjects and seven experienced rowers. Each subject was asked to perform three 2-min constant-load exercises performed at 60, 90 and 120% of the mean power output over a maximal 2,000-m event (denoted as P60, P90, and P120, respectively). A decomposition algorithm (nonnegative matrix factorization) was used to extract the muscle synergies that represent the global temporal and spatial organization of the motor output. The results showed a main effect of power output for 22 of 23 muscles (p values ranged from <0.0001 to 0.004) indicating a significant increase in EMG activity level with power output for both untrained and experienced subjects. However, for the two populations, no dramatic modification in the shape of individual EMG patterns (mean r (max) value = 0.93 ± 0.09) or in their timing of activation (maximum lag time = -4.3 ± 3.8% of the rowing cycle) was found. The results also showed a large consistency of the three extracted muscle synergies, for both synergy activation coefficients (mean r (max) values range from 0.87 to 0.97) and muscle synergy vectors (mean r values range from 0.70 to 0.76) across the three power outputs. In conclusion, despite significant changes in the level of muscle activity, the global temporal and spatial organization of the motor output is very little affected by power output on a rowing ergometer.
In this study, the injury incidence and association with type and volume of training in international rowers were described.
A prospective cohort design was used over a 12-month period.
20 international rowers who were competing as part of the Irish Amateur Rowing Union squad system.
The rowers were interviewed monthly, and data were collected regarding their training and competition exposure as well as their injury experience.
A mean injury rate of 3.67 per 1000 exposure hours was reported with a total of 44 injuries reported in a 12-month period. The mean number of injuries sustained per athlete was 2.2 (1.24) over the 12-month period. The area where the greatest number of injuries were reported was the lumbar spine (31.82% of total injuries, 95% CI 20 to 50) (fig 2) followed by the knee (15.91% of total injuries, 95% CI 10 to 30) and the cervical spine (11.36% of total injuries, 95% CI 5 to 24). Half of the injuries (22 injuries, 50% of total reported injuries) were to the spine (chi(2) = 30.8, df = 9, p = 0.0003). Ergometer training load was the most significantly associated with injury risk (r = 0.68, p = 0.01).
International rowers are at higher risk of injury than most non-contact sports and some contact sports. The high risk of lumbar spine injury and the significant association of high volume of ergometer training merit further research to reduce time and competition lost to injury.
Exercise has important effects on skeletal mineralization. Changes in bone mineral density (BMD) and bone mineral content (BMC) as measured by dual energy X-ray absorptiometry were investigated in a group of 17 male novice college oarsmen over a 7-month period and were compared with eight age-matched controls. The rowing training programme consisted of approximately 8 h rowing, 1 h weight training, and 1 h running per week. After 7 months training the mean BMD of the lumbar spine (L1-L4) had increased significantly by 2.9% (P < 0.001) and the mean BMC had increased by 4.2% (P < 0.001). There was no significant change in the control group. Neither group showed a significant change in BMD or BMC in the femoral neck, greater trochanter or Ward's triangle. This study provides further evidence that exercise plays an important role in bone mineral formation.
This study examined the influence of age, gender and weight category upon measures associated with eating disorders. Elite rowers (N = 124) participating in the 1994 Great Britain National Squad trials, completed the Eating Attitude Test (EAT) and the Body Shape Questionnaire (BSQ). Subjects were grouped according to whether they competed in the Lightweight (Female: < 59 kg, N = 31; Male: < 72.5 kg, N = 31) or Heavyweight (Female: N = 31; Male: N = 31) category. Results revealed significantly higher EAT and BSQ scores among the Lightweight group, 16.2% of whom showed EAT scores above the threshold associated with eating disorders. Females showed significantly higher BSQ scores than males. The interaction effect was significant for BSQ, indicating a much greater increase in scores from heavyweight to lightweight for females than for males. EAT and BSQ scores were inversely correlated with age. These results suggest that the risk of eating disorders among elite rowers is mediated by age, gender and weight category.
The study assessed the influence of age, gender and weight category upon eating attitudes, body shape perceptions, and mood. Elite rowers (N = 103) participating in the 1996 World Championships or Great Britain National Championships completed the Eating Attitude Test (EAT), the Body Shape Questionnaire (BSQ), and a short form of the Profile of Mood States (POMS-C). Participants were grouped as lightweight (Female: < 59 kg, n = 19; Male: < 72.5 kg, n = 31) or heavyweight (Female: n = 25; Male: n = 28) competitors. Results showed higher EAT scores among the lightweight group, 12.0% of whom reported scores above the threshold associated with eating disorders. Body shape concerns were higher for heavyweights than lightweights and for females than males. The interaction effect was not significant. BSQ scores were negatively correlated with age. Depression, Confusion and Tension scores collectively predicted 37% of the variance in BSQ scores while Depression scores predicted 9% of the variance in EAT scores. The results provide further evidence that the risk of eating disorders among elite rowers is moderated by age, gender and weight category. Further, they suggest that measures of mood may help identify athletes at risk from eating disorders.
A total of 693 female U.S. Marine Corps recruits were studied with anthropometry and dual-energy X-ray absorptiometry (DXA) scans of the midthigh and distal third of the lower leg prior to a 12 week physical training program. In this group, 37 incident stress fracture cases were radiologically confirmed. Female data were compared with male data from an earlier study of 626 Marine recruits extended with additional cases for a total of 38 stress fracture cases. Using DXA data, bone structural geometry and cortical dimensions were derived at scan locations and muscle cross-sectional area was computed at the midthigh. Measurements were compared within gender between pooled fracture cases and controls after excluding subjects diagnosed with shin splints. In both genders, fracture cases were less physically fit, and had smaller thigh muscles compared with controls. After correction for height and weight, section moduli (Z) and bone strength indices (Z/bone length) of the femur and tibia were significantly smaller in fracture cases of both genders, but patterns differed. Female cases had thinner cortices and lower areal bone mineral density (BMD), whereas male cases had externally narrower bones but similar cortical thicknesses and areal BMDs compared with controls. In both genders, differences in fitness, muscle, and bone parameters suggest poor skeletal adaptation in fracture cases due to inadequate physical conditioning prior to training. To determine whether bone and muscle strength parameters differed between genders, all data were pooled and adjusted for height and weight. In both the tibia and femur, men had significantly larger section moduli and bone strength indices than women, although women had higher tibia but lower femur areal BMDs. Female bones, on average, were narrower and had thinner cortices (not significant in the femur, p = 0.07). Unlike the bone geometry differences, thigh muscle cross-sectional areas were virtually identical to those of the men, suggesting that the muscles of the women were not relatively weaker.
Ergometer training is a common cause of injuries in rowers. A randomised crossover study comparing two power head designs was carried out to examine ergonomic risk factors.
Six elite male rowers undertook 20 minute fatiguing rowing pieces with both fixed and floating power heads. A CODA MPX infrared telemetric motion analysis detector and the ergometer's interface were used to measure displacement, force, work performed, and power output.
There was no significant difference in the total work performed, power per stroke, or metabolic load between the two ergometer designs. Fatigue was shown by a mean (SEM) fall of 9.7 (0.79) W/stroke (95% confidence interval (CI) 8.0 to 11.5) between minutes 8-10 and minutes 16-18 (p<0.001). The stroke length was 53 (13) mm (95% CI 18 to 89) longer with the fixed power head (p<0.02). With fatigue, the stroke with the fixed power head lengthened at the "catch" (beginning of the stroke) by 19.5 mm (p<0.01) and shortened at the finish of the stroke by 7.2 mm (p<0.05). No significant changes in stroke length were seen with the floating power head. The mean force per stroke was 12.1% (95% CI 3.0 to 21.2) (27.3 (8.0) N) higher with the power head fixed versus floating (p<0.02).
It is postulated that longer stroke lengths and greater forces are risk factors for soft tissue injuries. Further research into whether floating power head rowing ergometers are associated with lower injury rates than fixed power head designs is now needed.
Rib stress fractures are a common and significant problem in the rowing population. They occur in approximately 6.1 to 12% of rowers and account for the most time lost from on-water training and competition. This review discusses possible causative factors for rib stress fractures in rowers. Central to the establishment of causative factors is the identification that each rib forms part of a closed ring of bone that is completed anteriorly by the sternum and posteriorly by the thoracic vertebrae. Because of the shared sternum anteriorly each ring of bone is mechanically connected. Subsequently, during rowing individual ribs are not loaded in isolation, rather the rib cage is loaded as a complete unit. Incorporating this functioning as a complete unit a possible mechanism by which different factors contribute to rib stress fracture can be developed. In rowing, muscle factors generate loading of the rib cage. The characteristics of this loading stimulus are influenced by equipment, technique and joint factors. Rib-cage loading generates bone strain in individual ribs with the response of each rib depending upon site-specific skeletal factors. Depending on the characteristics of the bone strain in terms of the magnitude and rate of strain, microdamage may develop. The bone response to this microdamage is reparative remodelling. Whether this response is capable of repairing the damage to prevent progression to a stress fracture is dependent upon training and gender factors. Identification of these factors will generate a better understanding of the aetiology of this injury, which is required for improved prevention and treatment strategies.
Stress fractures are common among female athletes, especially runners. Although both intrinsic and extrinsic factors can contribute to stress injury etiology, the female athlete triad—negative energy balance leading to menstrual irregularity, and reduced bone mineral mass—is a significant contributor to the incidence of stress fractures in the female athlete. When combined with impact weight-bearing activity, this triad puts these women at increased risk for stress fractures. Treatment must focus on reversing identified risk factors, in addition to relative rest, and maintenance of fitness. Most stress fractures heal without complication. High-risk stress fractures should be evaluated and treated by a practitioner with expertise in the care of these injuries.
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Background:
Rib stress injury (RSI) is the development of pain due to bone oedema caused by overload along the rib shaft and is commonly seen in rowers. Often clinicians who manage this injury are experienced with the condition at the elite level. There may, however, be a lack of confidence in diagnosing and managing this condition by clinicians who are not regularly exposed to this injury. As a result, an evidence-based guideline has been developed to aid diagnosis and management of RSI.
Methods:
A detailed literature search was conducted reviewing the diagnosis and management of RSI. Detailed discussions were held by the Great Britain Rowing Medical Team to identify key issues in diagnosis and management of RSI. An up-to-date, evidence-based approach to managing RSI was created using both expert knowledge and current literature to formulate a functional guideline outlining best practice in management of RSI in rowers.
Results:
A clinical guideline has been created incorporating 5 key areas: diagnosis, severity grading, investigation, management and associated risk factors for RSI. Important indicators for each key area are incorporated within the guideline using relevant literature where possible alongside expert opinion. The guideline has deliberately been kept concise and tailored for use in the clinical setting.
Conclusions:
A new clinical guideline for management of RSIs has been developed to facilitate clinicians in identifying RSI, aiding accurate diagnosis and providing effective management. This guideline is to be disseminated to clinicians, rowing coaches and clubs throughout the UK.
Rib stress fractures (RSFs) are injuries frequently sustained by elite rowers with an injury rate of 8-16% over the course of a rowing career, resulting in negative effects on training and performance. For clinical management, the aim of this review was to describe time to return to sports, summarize potentially preventive measures and appraise the evidence on risk factors.
A search strategy was performed in PubMed, SportDiscus, Web of Science and Embase till June 1st 2015. All studies were graded on their quality.
The search resulted in 124 studies, of which 17 were included: Ten reported on return to sports, 17 reported on risk factors and nine on preventive measures. For return to sports, nine studies mentioned a loss of training of 4-6 weeks. The shortest period was one week and the longest 16 weeks. For risk factors, insufficient or conflicting evidence was found for changes in the training programme, incorrect rowing technique, female gender, low bone mineral density, inadequate equipment, and training type. For prevention, gradual changes in the training programme, alertness on the part of coaches and clinicians, and supplementation of diet and hormones are suggested as effective measures. However, no effect studies have been found.
The main outcome of this review on RSFs is that little evidence is available on return to sports, risk factors and preventive measures. Coaches and clinicians should carefully guide and assist rowers suffering from RSFs in off training and in the subsequent training period to regain their pre injury level.
Rib stress fracture (RSF) is one of the most hotly debated and least understood of all rowing injuries. It has recently been stated that ‘the pathology and prevention of rib stress fractures will be one of the most useful areas of research in rowing injuries’.1 There is a pressing need for more quality research of RSF aetiology and epidemiology that will inform effective prevention strategies. The current ‘best practice’ management of RSF is principally based on clinical experience and expert opinions from the 20th century.2-4 This is likely due to few major advances within the field of stress fracture healing. Current management strategies, therefore, focus mainly on fitness maintenance and a graded return to rowing.
Weight-bearing physical activity has beneficial effects on bone health across the age spectrum. Physical activities that generate relatively high-intensity loading forces, such as plyometrics, gymnastics, and high-intensity resistance training, augment bone mineral accrual in children and adolescents. Further, there is some evidence that exercise-induced gains in bone mass in children are maintained into adulthood, suggesting that physical activity habits during childhood may have long-lasting benefits on bone health. It is not yet possible to describe in detail an exercise program for children and adolescents that will optimize peak bone mass, because quantitative dose-response studies are lacking. However, evidence from multiple small randomized, controlled trials suggests that the following exercise prescription will augment bone mineral accrual in children and adolescents: Mode: impact activities, such as gymnastics, plyometrics, and jumping, and moderate intensity resistance training; participation in sports that involve running and jumping (soccer, basketball) is likely to be of benefit, but scientific evidence is lacking Intensity: high, in terms of bone-loading forces; for safety reasons, resistance training should be <60% of 1-repetition maximum (IRM) Frequency: at least 3 d·wk-1 Duration: 10-20 min (2 times per day or more may be more effective) During adulthood, the primary goal of physical activity should be to maintain bone mass. Whether adults can increase bone mineral density (BMD) through exercise training remains equivocal. When increases have been reported, it has been in response to relatively high intensity weight-bearing endurance or resistance exercise; gains in BMD do not appear to be preserved when the exercise is discontinued. Observational studies suggest that the age-related decline in BMD is attenuated, and the relative risk for fracture is reduced, in people who are physically active, even when the activity is not particularly vigorous. However, there have been no large randomized, controlled trials to confirm these observations, nor have there been adequate dose-response studies to determine the volume of physical activity required for such benefits. It is important to note that, although physical activity may counteract to some extent the aging-related decline in bone mass, there is currently no strong evidence that even vigorous physical activity attenuates the menopause-related loss of bone mineral in women. Thus, pharmacologic therapy for the prevention of osteoporosis may be indicated even for those postmenopausal women who are habitually physically active. Given the current state of knowledge from multiple small randomized, controlled trials and large observational studies, the following exercise prescription is recommended to help preserve bone health during adulthood: Mode: weight-bearing endurance activities (tennis; stair climbing; jogging, at least intermittently during walking), activities that involve jumping (volleyball, basketball), and resistance exercise (weight lifting) Intensity: moderate to high, in terms of bone-loading forces Frequency: weight-bearing endurance activities 3-5 times per week; resistance exercise 2-3 times per week Duration: 30-60 min·d -1 of a combination of weight-bearing endurance activities, activities that involve jumping, and resistance exercise that targets all major muscle groups It is not currently possible to easily quantify exercise intensity in terms of bone-loading forces, particularly for weight-bearing endurance activities. However, in general, the magnitude of bone-loading forces increases in parallel with increasing exercise intensity quantified by conventional methods (e.g., percent of maximal heart rate or percent of 1RM). The general recommendation that adults maintain a relatively high level of weight-bearing physical activity for bone health does not have an upper age limit, but as age increases so, too, does the need for ensuring that physical activities can be performed safely. In light of the rapid and profound effects of immobilization and bed rest on bone loss, and the poor prognosis for recovery of mineral after remobilization, even the frailest elderly should remain as physically active as their health permits to preserve skeletal integrity. Exercise programs for elderly women and men should include not only weight-bearing endurance and resistance activities aimed at preserving bone mass, but also activities designed to improve balance and prevent falls. Maintaining a vigorous level of physical activity across the lifespan should be viewed as an essential component of the prescription for achieving and maintaining good bone health.
Little is known about the true extent and severity of overuse injuries in sport, largely because of methodological challenges involved in recording them. This study assessed the prevalence of overuse injuries among Norwegian athletes from five sports using a newly developed method designed specifically for this purpose. The Oslo Sports Trauma Research Center Overuse Injury Questionnaire was distributed weekly by e-mail to 45 cross-country skiers, 98 cyclists, 50 floorball players, 55 handball players, and 65 volleyball players for 13 weeks. The prevalence of overuse problems at the shoulder, lower back, knee, and anterior thigh was monitored throughout the study and summary measures of an injury severity score derived from athletes' questionnaire responses were used to gauge the relative impact of overuse problems in each area. The area where overuse injuries had the greatest impact was the knee in volleyball where, on average, 36% of players had some form of complaint (95% CI 32-39%). Other prevalent areas included the shoulder in handball (22%, 95% CI 16-27%) the knee in cycling (23%, 95% CI 17-28%), and the knee and lower back in floorball (27%, 95% CI 24-31% and 29%, 95% CI 25-33%, respectively).
This study investigated maximal and submaximal performance (power output) and physiological responses (oxygen uptake, heart rate and blood lactate concentration) of eight male rowers to two different incremental tests to exhaustion performed either in a rowing ergometer without (regular) or with the slide, as well as to a 2000 m race simulation, conducted in a randomized order. Peak oxygen uptake ([Formula: see text]O2peak) was statistically higher (3.4%) in the regular test (5.18 ± 0.44 L.min(-1)) compared with the slide condition (5.01 ± 0.37 L.min(-1); P = 0.005). Time for the on-water race simulation was significantly correlated with the slope of the [Formula: see text]O2-power relationship in the slide condition (r = -0.73, P = 0.043) and [Formula: see text]O2peak during the test in the slide condition was correlated to mean [Formula: see text]O2 at the on-water race simulation (r = 0.78; P = 0.024). Thus, the use of the slide is more beneficial than the regular test when evaluating rowers.
Objective: chest muscle action has been proposed as a cause of rib stress fractures in rowers. The objective was to examine the sequence of peak chest muscle electromyography (EMG) activity and ribcage compression during the rowing stroke. Design: a within-groups, repeated measures design was used. Subjects and Setting: seventy-four rowers (34 male, 40 female) from elite, club and school levels of competition were tested at the Australian Institute of Sport in Canberra or the School of Physiotherapy at the University of Melbourne. Method: surface EMG was used to measure timing of peak activity of serratus anterior (SA) and obliquus externis abdominis (OEA). An extensometer indicated the time of maximal ribcage compression (RC). Subjects used a rowing ergometer and the sequence of these events was examined. Results: SA peak activity occurred just before the catch while OEA peak activity occurred at the finish of the stroke. RC followed OEA closely, and was not coincident with peak SA activity. Results were consistent across the levels of rowing experience. Conclusion: a consistent sequence of peak muscle activity and RC was found, with RC following OEA activity closely. This indicates that the ribs may undergo compressive stressing via OEA activity rather than SA activity in rowing.
This article outlines principles relating to the assessment of risk factors and causation in sport injury. The limitations of a univariate exploration of risk factors are outlined, and a new model that permits the assessment of multiple risk factors is proposed. Applying this multivariate model may lead to greater success in predicting athletic injuries and help guide effective prevention strategies.
(C) Lippincott-Raven Publishers.
Force production profile and neuromuscular activity during slide-based and stationary ergometer rowing at standardized submaximal power output were compared in 14 male and 8 female National Team rowers. Surface electromyography (EMG) was obtained in selected thoracic and leg muscles along with synchronous measurement of handle force and rate of force development (RFD). Compared to stationary conditions, slide-based peak force decreased by 76 (57-95) N (mean 95% CI) in males (P < 0.001) and 20 (8-31) N (P < 0.05) in females. Stroke rate increased (+10.7%) and late-phase RFD decreased (-20.7%) in males (P < 0.05). Neuromuscular activity in m. vastus lateralis decreased in the initial drive phase from 59% to 51% of EMGmax in males and from 57% to 52% in females (P < 0.01-0.05), while also decreasing in the late recovery phase from 20% to 7% in males and 17% to 7% in females (P < 0.01). Peak force and maximal neuromuscular activity in the shoulder retractors always occurred in the second quartile of the drive phase. In conclusion, peak force and late-phase RFD (males) decreased and stroke rate increased (males) during slide-based compared to stationary ergometer rowing, potentially reducing the risk of overuse injury. Neuromuscular activity was more affected in leg muscles than thoracic muscles by slide-based ergometer rowing.
The effect of rowing ergometer design upon power delivery and coordination patterns of the rowing stroke was analyzed for 14 elite rowers. Rowers were tested in three ergometer conditions: the fixed stretcher Concept2c ergometer, the Concept2c ergometer mounted on sliding rails, and the sliding stretcher RowPerfect ergometer. Ergometers were instrumented to measure the external force generated at the handle and the foot stretcher and a nine-segment inverse dynamics model used to calculate joint and overall power delivery. Peak power generation and absorption at the knee joint was significantly greater, and total power delivered to the ergometer delayed on the fixed stretcher ergometer when compared to the sliding stretcher ergometers. No differences were found in the mechanical energy delivered to the handle of the three ergometers; however, greater joint mechanical energy production of the lower limb reduced mechanical efficiency when rowing the Concept2c fixed ergometer. The fixed foot stretcher on the Concept2c fixed ergometer acts to increase the inertial forces that the rower must overcome at the catch, increasing the moment and power output at the knee, and affecting the coordination pattern during the recovery phase.
A rowing ergometer can be placed on a slide to imitate 'on-water' rowing. The present study examines I) possible differences in biomechanical and physiological variables of ergometer rowing with and without slides and II) potential consequences on training load during exercise. 7 elite oars-women rowed in a randomized order in a slide or stationary ergometer at 3 predefined submaximal and at maximal intensity. Oxygen uptake was measured and biomechanical variables of the rowing were calculated based upon handle force (force transducer) and velocity/length (potentiometer) of the stroke. Stroke frequency was higher (%-difference between conditions) at each intensity level (1-11.4%, p<0.05) during slide compared to stationary rowing. Furthermore, at the 2 highest intensities a lower mean force (4.7-9.0%, p<0.05) and max force (3.2-10.6%, p<0.05) were observed on the slide ergometer. During maximal rowing no difference was seen in heart rate, mean oxygen uptake and R-value while maximal oxygen deficit was higher (30.8%, p<0.05) during slide rowing. In conclusion the biomechanical load is lower on a slide than on a stationary ergometer. However, as a training tool the slide ergometer seems just as demanding with regard to aerobic energy sources, and for anaerobic sources possibly even higher, compared with the stationary ergometer.
Overuse injuries may represent as much of a problem as do acute injuries in many sports. This paper reviews key concepts related to the methodology for recording overuse symptoms. Results from the FIVB Volleyball Injury Study were used to compare two different recording methods. The aim of this paper was to provide recommendations on how standardised methodology can be developed to quantify overuse injuries in surveillance studies. Using beach volleyball data, a "traditional" cohort study approach using a time-loss injury definition suggested that injury risk was very low. In contrast, the data from a survey of past and present pain problems in the shoulder, knees and low back demonstrated that these were prevalent. The following recommendations are made: (1) studies should be prospective, with continuous or serial measurements of symptoms; (2) valid and sensitive scoring instruments need to be developed to measure pain and other relevant symptoms; (3) prevalence and not incidence should be used to report injury risk; (4) severity should be measured based on functional level and not time loss from sports. In conclusion, new approaches are needed to develop more appropriate methodology to quantify overuse injuries in studies.
The purpose of this study was to characterize the EMG of trunk muscles together with kinematics of the pelvis and the spine of elite female rowers during the rowing stroke.
Nine Rowing Canada national team candidates performed a 2000-m race simulation. EMG activity of spinal and pelvic extensor and flexor muscles and kinematic data of the pelvis and the spine were collected and analyzed during the period of peak force production.
During this period, pelvic and spinal extensor muscles demonstrated similarities in the timing of muscle activity with minimal coactivation of flexors and extensors. Minimal excursion of spinal segments occurred during the stroke with most of the extension occurring at the pelvis. Flexor activity occurred toward late drive, suggesting that trunk extension is slowed by increasing activity of the flexor muscles.
This study provides data of trunk kinematics and muscle recruitment patterns in elite female rowers. During the period of peak force production, there is minimal coactivation of trunk flexor and extensor muscles and, of the spinal segments, L3-S1 shows the most movement, which may make it more susceptible to soft tissue injury.
An increasing number of investigative research studies point to participation in endurance exercise training as having significant detrimental effects upon reproductive hormonal profiles in men. Specifically, men chronically exposed to this type of exercise training exhibit persistently reduced basal (resting-state) free and total testosterone concentrations without concurrent LH elevations. Men displaying these symptoms have been deemed to exhibit the "exercise-hypogonadal male condition". The exact physiological mechanism inducing the reduction of testosterone in these men is currently unclear, but is postulated to be a dysfunction (or perhaps a readjustment) within the hypothalamic-pituitary-testicular regulatory axis. The potential exists for the reduced testosterone concentrations within exercise-hypogonadal men to be disruptive and detrimental to some anabolic-androgenic testosterone- dependent physiological processes. Findings on this point are limited, but do suggest spermatogenesis problems may exist in some cases. Alternatively, reductions in circulating testosterone concentrations could have cardiovascular protective effects and thus be beneficial to the health of these men. Present evidence suggests the exercise-hypogonadal condition is limited to men who have been persistently involved in chronic endurance exercise training for an extended period time (i.e., years), and it is not a highly prevalent occurrence (although, a thorough epidemiological investigation on the topic is lacking in the literature). Many questions regarding the male reproductive endocrine adaptive process to exercise training still remain unanswered, necessitating the need for much further investigation on the topic, especially with respect to the exercise-hypogonadal condition.
In 1983, a 31% incidence of stress fractures was found among Israeli basic infantry recruits.
The purpose of this article is to chronicle the efforts of the Israeli Defense Forces to lower the stress fracture incidence and to present new data showing how reduction was finally achieved.
A historical review of the steps taken over the past 25 yr to decrease stress fracture incidence in the Israeli Army is presented: risk factors for stress fracture were identified to create a risk profile and facilitate screening of recruits; modifications in army shoes were made; shock attenuating orthoses and biomechanical orthoses of various compositions were used; and the bisphosphonate risedronate was administered to recruits before and during basic training. In the latest intervention, the combined effect of a minimum nightly sleep requirement (6 h a night) and a decrease in recruits' cumulative marching and running on the incidence of stress fractures was evaluated among 276 infantry recruits.
A stress fracture risk profile was developed. It allows a recruit's stress fracture risk to be calculated before infantry training. Shoe modifications, orthoses, and pharmacological treatment with risedronate were not effective in lowering the incidence of stress fractures. The minimum sleep regimen and the reduced cumulative marching lowered the incidence of stress fractures by 62% (from 30.8% to 11.6%) and decreased their severity as compared with the 1983 baseline study.
After failing in prior interventions, a more than 60% decrease in stress fracture incidence was achieved by enforcing a minimum sleep regimen and lowering the cumulative marching during infantry training. These changes did not affect the quality of the training or the soldiers' combat readiness.
Notwithstanding the healthy influence of sporting activities on risk factors, in particular those of cardiovascular disease, it is becoming increasingly apparent that sports can present a danger to health in the form of sports injuries. The extent of the sports injury problem calls for preventative action based on the results of epidemiological research. For the interpretation of these facts uniform definitions are needed and limitations of research designs should be known. Measures to prevent sports injuries form part of what is called the ‘sequence of prevention’. Firstly the extent of the sports injury problem must be identified and described. Secondly the factors and mechanisms which play a part in the occurrence of sports injuries have to be identified. The third step is to introduce measures that are likely to reduce the future risk and/or severity of sports injuries. This measure should be based on the aetiological factors and the mechanism as identified in the second step. Finally the effect of the measures must be evaluated by repeating the first step.
In this review some aspects of the first and second step of the sequence of prevention are discussed.
The extent of the sports injury problem is often described by injury incidence and by indicators of the severity of sports injuries. Sports injury incidence should preferably be expressed as the number of sports injuries per exposure time (e.g. per 1000 hours of sports participation) in order to facilitate the comparability of research results. However, one should realise that the outcome of research applying this definition of sports injury incidence is highly dependent on the definitions of ‘sports injury’ and ‘sports participation’.
The outcome of such research also depends on the applied research design and research methodology. The incidence of sports injuries depends on: the method used to count injuries (e.g. prospective vs retrospective); the method used to establish the population at risk; and on the representativeness of the sample.
Severity of sports injuries can be described on the basis of 6 criteria: the nature of the sports injury; the duration and nature of treatment; sporting time lost; working time lost; permanent damage; and cost. Here also uniform definitions are important and necessary in order to enhance the comparability of research data. In the second step of the ‘sequence of prevention’ the aetiological factors that play a role in the occurrence of a sports injury have to be identified by epidemiological studies. Epidemiological research on the aetiology of sports injuries requires a conceptual model. The most commonly applied model is a stress/capacity model in which internal (personal) and external (environmental) aetiological factors are identified. In this model stress and capacity must be in balance and preventative measures must be designed to achieve or maintain this balance. However, merely to establish the aetiological factors is not enough; the mechanism by which sports injuries occur must also be identified. Athletes are in constant interaction with their environment and aetiological factors must be approached from this point of view. In a second, more dynamic, conceptual model on the aetiology of sports injuries, the importance of the determinants of sports behaviour, as well as the interaction between the various aetiological factors, is discussed. Whether or not a sports injury results from sports behaviour largely depends on the extent to which ‘prevention’ is incorporated in the determinants of sports behaviour. The drawback of both conceptual models is the fact that neither of them incorporate a time perspective. They can therefore not be applied to research on the aetiology of overuse injuries. In this perspective the application of a stress/strain/capacity model can be useful. This is a more dynamic and time-based 3-phase sequential model in which behaviour, amongst other aetiological factors, plays an important role. In this model an athlete is seen as an active manipulator of stress by whom the amount of strain evoked by sports participation can be altered, thereby influencing the capacity to perform in a certain sports situation, but also influencing the risk to sustain a sports injury, either acute or long term.
Finally, despite the importance of the model of choice in studying the aetiology of sports injuries one should realise that again the choice of research design influences the outcome of such research. Case series usually give no information on the underlying population at risk, so they are of no value in drawing valid conclusions on the risk factors of injuries. Only by relating the injuries to corresponding population denominators can one estimate injury rates and identify important risk factors and high risk sportspeople. As in research on sports injury incidence; research on risk factors should be undertaken on groups that are homogeneous with regard to age, sex, level of competition and type of sport.
Electromyography was used to study muscle activity in the upper and lower extremities and torso during the rowing stroke. Five experienced male rowers were tested while rowing on a Concept II ergometer. In order to fully evaluate the rowing stroke, six phases were utilized to identify the transition points where individual muscles become more active due to body angle or nature of the motion. The results indicate that the strength of an individual muscle is most likely not as important to the rowing stroke as the combined activity of two or more groups of muscles. Thus, in addition to strength, it is of great value to the oarsman to develop technical skill to coordinate his upper and lower body reactions.
This paper documents an unusual case of a stress fracture of the ninth rib in an elite oarsman. A 25-year-old male presented with a 3-day history of right-sided chest pain aggravated by deep inspiration and movements simulating rowing. The athlete was treated initially as having a soft tissue injury; however, a technetium-99 bone scan confirmed the diagnosis. Routine radiographs of the ribs were negative. The pain and symptoms were confined to the anatomical area of the fracture along the anterolateral portion of the rib where the serratus anterior muscle originates. An analysis of the stroke mechanics involved in rowing implicated the serratus anterior muscle as being a major contributor to the repetitive stress that resulted in the injury. The primary etiological factor was errors in the training program. The athlete responded to simple conservative measures and was able to return to competitive rowing in 1 month's time.
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Stress fractures of the lower ribs related to sports are rare. Fractures of the ribs related to rowing sports have not been reported. We have documented seven cases of stress fractures of the lower ribs in female athletes; four were elite rowers and three were engaged in tennis, golf, and gymnastics. Each athlete was initially seen and treated elsewhere for muscular strain. All athletes presented with pain in the posterolateral thorax in and around the scapula. The time from onset of symptoms to diagnosis ranged from 2 to 6 months. Bone scans were used to document the fractures when roentgenograms were equivocal. Each athlete responded to a 4 to 8 week period of rest or training modification. Biomechanical analysis of the forces across the ribs demonstrates that these fractures tend to occur along the posterolateral segment where the bending stresses on the rib are greatest. The predominant muscle forces are generated by the forced couple of scapular retraction and protraction acting through the serratus anterior. We postulate that inadequate strength and resistance training background in women is the cause for the apparent increased susceptibility of women to these skeletal injuries.
In rowing, stress fractures are rare. However, the intensity of training has increased in terms of more specific rowing movements throughout the year. Simultaneously, new equipment has been developed resulting in faster rowing over the racing distance with increased risk of injuries on bones, muscles and ligaments. We report five cases of chest pain and one case of pain in the shoulder in national elite rowers, diagnosed as stress fractures of the ribs employing 99mTechnetium-MDP bone scan. In all cases, an increase or alteration in physical activity in the weeks prior to the injury and an increase in specific rowing movements with special emphasis on the new equipment, combined with increased biomechanical stress applied to the thoratic skeleton in the catch and the early part of the drive phase of the stroke, most probably caused the injuries.
The purpose of this study was to analyze retrospectively all injuries occurring in a population of elite rowers over a 10-yr period to determine their pattern of injury. The medical records of all rowers at the Australian Institute of Sport from 1985 to 1994 inclusive were reviewed and all injuries included. Injuries were categorized according to time, location, cause, and whether acute or chronic. The study found a significant incidence of chest injuries, rib stress fractures, and low back injuries, and a high number of injuries occurring outside specific training. Elite rowers have little risk of major injury, but mild and moderate injuries are common.
The potential cause of stress fractures of the rib in elite rowers was examined by a retrospective review of 14 fractures in 10 patients. Fractures occurred on the antero- to posterolateral aspects of ribs 5 through 9 and were most often associated with long-distance training and heavy load per stroke. A review of the literature yields striking similarities between these stress fractures and fractures caused by cough. It is suggested that actions of the serratus anterior and external oblique muscles on the rib cause stress fracture because of the repetitive bending forces in both rowing and coughing. A technique involving less use of both muscles through a truncated arm pull-through and a decreased layback position at the end of the stroke, and equipment changes to decrease length of the lever arm, should yield a decreased risk of rib stress fractures in rowing.
We report on a previously unreported site of rib stress fracture in an elite athlete. A 27 year old sweep rower, a National champion and an Olympic finalist, presented with a 3-day history of the left-side thoracic pain. Technetium 99m bone scintigraphy showed increased focal uptake of the radioisotope, leading to the diagnosis of stress injury of the anterolateral part of the sixth rib. The probable mechanism of this injury was that strong muscle force itself was great enough to produce a fracture. In the case of our rower, the precipitation cause was only a slight change in the rowing technique, in contrast to all other reports on such rib fractures among rowers where the primary cause was an increase in the level of strength training. The treatment included a complete rest of the affected area and upper extremities, while the cardiovascular and strength fitness was maintained. The athlete was able to resume with his standard training routine less than four weeks after the onset of the symptoms.
Rowers have and accrue greater lumbar spine bone mineral density (BMD) associated with mechanical loading produced during rowing. The aim of this study was to estimate the mechanical loading generated at the lumbar spine (LS) that is apparently providing an osteogenic benefit. The cohort comprised 14 female rowers (average age: 19.7yrs; height: 170.9 cm, weight: 59.5 kg) and 14 female matched controls (average age: 20.9 m yrs; height: 167.5 cm; weight: 58.1 kg). BMD was assessed using the Hologic QDR 2000+ bone densitometer, indicating higher lumbar spine BMD in the rowers compared to the control subjects (1,069 +/- 0.1 vs. 1,027 +/- 0.1 g/cm2). No significant difference existed for BMD at any other site. All rowers performed a six-minute simulated race on a Concept II rowing ergometer. Mechanical loading generated at the lumbar spine during this task was assessed using a two-dimensional model of the spine, enabling the calculation of the compressive and shear forces at L4/L5. The shear force was the joint reaction force perpendicular to the spine at the L4/L5 joint. Peak compressive and shear force at the lumbar spine of the rowers were 2,694 +/- 609 (N) and 660 +/- 117 (N), respectively. Peak compressive force at the LS relative to body weight was 4.6 times body weight. The literature would suggest that forces of this magnitude, generated at the LS during maximal rowing, may be contributing to the site specific higher LS BMD found in the rowers.