Effectiveness of an 18-week general strength and foam-rolling intervention on running-related injuries in recreational runners.

RATIONALE: More research is needed to uncover the effectiveness of combined strength and foam-rolling interventions to prevent running-related injuries. OBJECTIVES: To evaluate effectiveness of an 18-week general strength and foam-rolling intervention on the incidence of running-related injuries. METHOD: This is an 18-week observational comparative study. A total of 433 recreational runners participated (n = 203 female). The intervention group (n = 228) performed general strength and foam-rolling exercises twice weekly for 18 weeks, the control group (n = 205) maintained their regular training habits. Running volume and running-related pain were reported weekly. Secondary analyses were performed on the subgroups of the intervention group based on compliance; low compliance (n = 100), intermediate compliance (n = 63), and high compliance (n = 65). Cumulative incidence proportions were calculated and time-to-event statistics were performed to compare survival times between groups. Univariate cox proportional hazards ratio was calculated to estimate the risk of running-related injuries at 18 weeks. RESULTS: A total of 100 running-related injuries were sustained. The cumulative incidence proportion for the control and intervention groups was 27.1% (95% CI: 21.4-33.9) and 23.0% (95% CI: 17.8-29.4), respectively. No statistically significant difference was found between the overall intervention group and control group (log-rank p = 0.31). A significant difference existed between the high-compliance subgroup and the control group (log-rank p = 0.00). Highly compliant runners were 85% less likely (hazard rate ratio = 0.15; 95% CI: 0.05-0.46) to sustain an injury during the study compared with controls. CONCLUSION: Recreational runners highly compliant with the intervention were 85% less likely and took on average 57 days longer to sustain a running-related injury when compared with controls, with a cumulative incidence proportion of 4.6% after 18 weeks.

Risk factors for overuse injuries in a cohort of elite Swedish track and field athletes.

BACKGROUND: Most injuries in track and field are caused by overuse with conflicting reports concerning the underlying mechanisms. The purpose of this study was to evaluate how biomechanical and clinical factors relate to the risk of overuse injuries, and to investigate whether the relationships between potential risk factors and injury become stronger if injuries are grouped by location. METHODS: The study is a prospective cohort study conducted during a Swedish track and field season over eleven months, from October to August. The cohort consisted of elite male and female track and field athletes competing in either middle- and long-distance running, sprinting, jumping, or throwing events (n = 96). Athletes performed a baseline screening at enrollment consisting of a clinical examination, running, and strength tests. Injury data was collected during the season by medical professionals and divided according to their anatomical location into upper-body, thigh/hip, knee, or foot/shank injuries. RESULTS: Thirty-four (54.8%) injuries where located at the foot/shank, followed by sixteen injuries at the thigh/hip (25.8%). Only eight knee (12.9%) and four upper-body (6.5%) injuries were registered during the season and therefore not analysed. Effect sizes were calculated for all test variables. Small effect sizes (rpb = .10-.23) were found for eleven risk factors between the overall injured (all injuries combined) and non-injured athletes. By further sub-grouping the injured group into thigh/hip injuries, effect size increased in hip adduction range of motion knee flexion velocity and the muscle flexibility of the iliopsoas. For foot/shank injuries, only the hamstring:quadriceps strength ratios increased for the right side to a small effect size. CONCLUSIONS: Injury grouping appears to increase effect size for certain risk factors. Athletes with a slower knee flexion velocity during stance phase were more likely to become injured (p-value <.03, rpb = .37). An increased cohort size to further sub-divide injuries into specific diagnoses is needed.

Recreational Runners With a History of Injury Are Twice as Likely to Sustain a Running-Related Injury as Runners With No History of Injury: A 1-Year Prospective Cohort Study.

OBJECTIVES: To investigate (1) the cumulative incidence proportion and the most common anatomical locations of running-related injuries in recreational runners, and (2) the associations between running-related injuries and previous injury, running experience, weekly running distance, age, sex, and body mass index. DESIGN: A 1-year prospective cohort study. METHODS: Two hundred twenty-four recreational runners (average weekly running distance for the past 12 months, 15 km) were included (89 women, 135 men). Pain information was reported weekly for 1 year, and all running-related injuries that resulted in time loss or medical consultation were recorded. We accounted for censoring when calculating cumulative incidence proportion, and used crude Cox proportional hazards regression to evaluate whether the variables of interest were associated with running-related injuries. RESULTS: The 1-year cumulative incidence proportion of running-related injuries was 45.9% (95% confidence interval [CI]: 38.4%, 54.2%). The most common anatomical locations were the knee (20/75, 27%) and Achilles tendon/calf (19/75, 25%). Previous injury was associated with a higher injury rate (hazard rate ratio = 1.9; 95% CI: 1.2, 3.2), while the other variables had no statistically significant association with injury. CONCLUSION: There were 75 running-related injuries during the 1-year surveillance period, for a cumulative incidence proportion of 46%. The most common injuries were to the knee and Achilles tendon/calf. Recreational runners with a previous injury were twice as likely to sustain a running-related injury as runners with no previous injury. J Orthop Sports Phys Ther 2021;51(3):144-150. Epub 25 Dec 2020. doi:10.2519/jospt.2021.9673.

Athlete availability and incidence of overuse injuries over an athletics season in a cohort of elite Swedish athletics athletes - a prospective study.

BACKGROUND: Athletics is a sport with a high incidence of injury, where most injuries are caused by overuse. Research on injury incidence and the occurrence of overuse injuries during a season in athletics is scarce. An athlete availability (unrestricted ability to participate in training or competition) of less than 80% has been linked with athletes being less likely to reach their performance goals. The purpose of this study was to estimate the monthly injury incidence rates, athlete availability, and the overuse injury incidence rate per 1000 athletics-hours of training in a cohort of Swedish elite athletics athletes. METHODS: The cohort consisted of 59 male and female elite athletes competing in either middle or long-distance running, sprint, or jumping events. Injury and training data were collected during one athletics season, from October to the end of August. All injury data were collected by medical professionals. Training data were collected monthly, and consisted of event-specific training diaries covering training sessions, training days, and non-training or non-competition days. Monthly injury incidence rates were based on the number of new injuries per month in relation to the number of exposed (injury-free) athletes. RESULTS: The overall injury incidence rate for all athletes was highest in October (22.0%). Monthly injury incidence rate for middle and long-distance runners was highest in October (26.1%), for sprinters in April (19.0%), and for jumpers in October (21.4%). The overall athlete availability was 78.0% for the cohort. Sprinters had the lowest athlete availability (71.4%), followed by jumpers (77.3%), and middle-distance and long-distance runners (82.7%). Female athletes (76.5%) had a lower athlete availability than male athletes (79.7%). The injury incidence rate was 1.81 injuries per 1000 athletics hours of training. Middle and long-distance runners had the highest injury incidence rate (2.38), followed by jumpers (1.62), and sprinters (1.34). CONCLUSION: Monthly injury incidence rates during a season appears to correspond to periods of high training volume (conditioning phases and training camps). The low overall athlete availability (> 80%) indicates that many Swedish elite athletes are less likely to reach their full potential.

Associations between biomechanical and clinical/anthropometrical factors and running-related injuries among recreational runners: a 52-week prospective cohort study.

BACKGROUND: The purpose of this exploratory study was to investigate whether runners with certain biomechanical or clinical/anthropometrical characteristics sustain more running-related injuries than runners with other biomechanical or clinical/anthropometrical characteristics. METHODS: The study was designed as a prospective cohort with 52-weeks follow-up. A total of 224 injury-free, recreational runners were recruited from the Gothenburg Half Marathon and tested at baseline. The primary exposure variables were biomechanical and clinical/anthropometrical measures, including strength, lower extremity kinematics, joint range of motion, muscle flexibility, and trigger points. The primary outcome measure was any running-related injury diagnosed by a medical practitioner. Cumulative risk difference was used as measure of association. A shared frailty approach was used with legs as the unit of interest. A total of 448 legs were included in the analyses. RESULTS: The cumulative injury incidence proportion for legs was 29.0% (95%CI = 24.0%; 34.8%). A few biomechanical and clinical/anthropometrical factors influence the number of running-related injuries sustained in recreational runners. Runners with a late timing of maximal eversion sustained 20.7% (95%CI = 1.3; 40.0) more injuries, and runners with weak abductors in relation to adductors sustained 17.3% (95%CI = 0.8; 33.7) more injuries, compared with the corresponding reference group. CONCLUSIONS: More injuries are likely to occur in runners with late timing of maximal eversion or weak hip abductors in relation to hip adductors.

Overuse injuries in Swedish elite athletics- a study protocol for a prospective multifactorial cohort study.

BACKGROUND: Overuse injuries (OI) are common in elite athletics. Previous studies have had athletes self-report injuries rather than having a medical professional provide a clear diagnosis. This might be a major reason for the inconsistencies in reported incident proportions of OI in elite athletics, in addition to the varying definitions of OI in current literature. Risk factors or combinations of risk factors (biomechanical, clinical, and training-related) have been shown to be important in the developmental process of OI. However, no studies have examined these relationships using a multifactorial and prospective approach in elite athletics. The purpose of this study protocol is to describe OI incidence proportion, injury severity, location, and occurrence during a complete athletics season. Moreover, possible discipline specific and injury specific risk factors that might be associated with OI will be examined. METHODS: This study will be an explorative prospective cohort study including approximately 120 elite athletes. All athletes will be screened twice during one complete athletics season. The screening will consist of a body composition scan to measure muscle mass, fat free mass, lean mass, bone density, and bone mineral content. In addition, clinical examination will measure range of motion for the lower back, hip, knee, shoulder, and elbow and ankle joints. A running analysis will measure the 3D motions of the hip, knee, and ankle joints. Finally, maximal isometric strength tests of the main core and lower extremity muscles will be carried out. To record injuries, each athlete will consult a physiotherapist or sports medicine doctor affiliated with the study to get a clear diagnosis. Injury data will be recorded according to the previously published athletics consensus statement. DISCUSSION: Results from this study protocol will contribute more insight and detailed knowledge regarding the extent of OI occurrence among elite athletes during a complete athletics season. It will also provide further insights into which risk factors are associated with the development of OI in elite athletics.

Study protocol of a 52-week Prospective Running INjury study in Gothenburg (SPRING).

INTRODUCTION: It is assumed that a running-related (overuse) injury occurs when a specific structure of the human body is exposed to a load that exceeds that structures' load capacity. Therefore, monitoring training load is an important key to understanding the development of a running-related injury. Additionally, other distribution, magnitude and capacity-related factors should be considered when aiming to understand the causal chain of injury development. This paper presents a study protocol for a prospective cohort study that aims to add comprehensive information on the aetiology of running-related injuries and present a new approach for investigating changes in training load with regard to running-related injuries. METHODS AND ANALYSIS: This study focused on recreational runners, that is, runners exposed to a minimum weekly average of 15 km for at least 1 year. Participants will undergo baseline tests consisting of a clinical/anthropometrical examination and biomechanical measurements. Furthermore, participants will log all training sessions in a diary on a weekly basis for 1 year. The primary exposure variable is changes in training load. A medical practitioner will examine runners suffering from running-related pain and, if possible, make a clear diagnosis. Finally, additional time-varying exposure variables will be included in the main analysis, whereas the analysis for the secondary purpose is based on time-fixed baseline-related risk factors. ETHICS AND DISSEMINATION: Ethical approval (DNR: 712-15) for the study and its design was obtained from the Gothenburg regional ethical review board. The results of the study will be published in peer-reviewed journals.