"I don't opt out of things because I think I will get a sore knee, but I don't expose myself to stupid risks either": patients' experiences of a second ACL injury-an interview study.

PURPOSE: The purpose of this qualitative study was to describe women's experiences with anterior cruciate ligament reconstruction (ACLR) and a subsequent ACL rupture, and to identify potential facilitators and barriers for coping with rehabilitation after the second injury. METHODS: Eight women between 17 and 36 years (mean 26, SD 6.5) who had experienced ACLR, followed by another ACL rupture, participated in the study. Semi-structured interviews were conducted, and data were analyzed using qualitative content analysis. RESULTS: One overarching theme, "Rehabilitation after a second ACL injury-A lifelong adaptive coping process", emerged from analyses. Undergoing a second rehabilitation is described as a process of adaptation, beginning with the first injury and still ongoing, more than 5 years later. Participants applied different coping strategies to adapt to these life-altering injuries, but the common denominator was of major life adjustments with no return to previous activity levels. Initially, after the reinjury, it was about coping with the catastrophe of the dreaded second injury. Over time, they accepted their "new" life and reset their recovery/rehabilitation goal not just as "return to sport" but rather as a "personal life goal". CONCLUSION: Undergoing a second ACL injury is a long process that challenges the patient's coping skills. Given these results, rehabilitation programs need to be more person centred according to the patients-adjusted life goals.

Early mobilization does not reduce the risk of deep venous thrombosis after Achilles tendon rupture: a randomized controlled trial.

PURPOSE: The hypothesis was that early functional mobilization would reduce the incidence of deep venous thrombosis (DVT) during leg immobilization after Achilles tendon rupture surgery. A secondary aim was to evaluate if the amount of weightbearing and daily steps influenced the risk of sustaining a DVT. METHODS: One-hundred and fifty patients with Achilles tendon rupture repair were randomized to treatment with early functional mobilization, encouraging full weightbearing and ankle motion in orthosis, or treatment-as-usual, i.e., 2 weeks of unloading in plaster cast followed by 4 weeks weightbearing in orthosis. At 2 and 6 weeks postoperatively, all patients were screened for DVT using compression duplex ultrasound. During the first 2 weeks postoperatively, patient-reported loading, pain and step counts were assessed. RESULTS: At 2 weeks, 28/96 (29%) of the patients in early functional mobilization group and 15/49 (31%) in the control group (n.s) had sustained a DVT. At 6 weeks, the DVT rate was 35/94 (37%) in the early functional mobilization and 14/49 (29%) in the control group (n.s). During the first postoperative week, the early functional mobilization group reported low loading and higher experience of pain vs. the control group (p = 0.001). Low patient-reported loading ≤ 50% (OR = 4.3; 95% CI 1.28-14.3) was found to be an independent risk factor for DVT, in addition to high BMI and higher age. CONCLUSIONS: Early functional mobilization does not prevent the high incidence of DVT during leg immobilization in patients with Achilles tendon rupture as compared to treatment-as-usual. The low efficacy of early functional mobilization is mainly explained by postoperative pain and subsequent low weightbearing. To minimize the risk of DVT, patients should be encouraged to load at least 50% of body weight on the injured leg 1 week after surgery. LEVEL OF EVIDENCE: Therapeutic, level 1.

A two- and five-year follow-up of clinical outcome after ACL reconstruction using BPTB or hamstring tendon grafts: a prospective intervention outcome study.

PURPOSE: The aim of the present study was to evaluate and compare objective and subjective outcome in patients 2 and 5 years after anterior cruciate ligament (ACL) reconstruction with either bone-patellar tendon-bone (BPTB) or hamstring grafts. The second aim was to report the prevalence of re- and contralateral ACL ruptures. METHODS: Sixty-eight patients (BPTB, n = 34 and hamstring graft, n = 34) were evaluated preoperatively, 2 and 5 years after ACL reconstruction. Anterior knee laxity and rotational knee joint stability, muscle torque, hop length, anterior knee pain, activity level and self-reported knee function and quality of life were evaluated within and between groups. The prevalence of re- and contralateral ACL ruptures was also recorded. RESULTS: No significant difference in anterior knee laxity, rotational knee joint stability, hop length anterior knee pain or knee function and quality of life were noted at the 5-year follow-up. No significant differences in concentric or eccentric quadriceps torque at 90°/s and 230°/s were found at any of the follow-ups between and within grafts. A significant group difference in hamstring torque 1.05 (0.02) for BPTB and 0.89 (0.02) for hamstring grafts, and in hop length (leg symmetry index) follow-up 0.94 (0.07) for BPTB compared to 0.99 (0.07) for hamstring grafts (P = 0.002) was found at the 2 year follow-up in favour of the BPTB graft, but not at the 5 year follow-up. A significant improvement over time, irrespective of graft, was found in the KOOS's subscales Sport/Rec and quality of life (P < 0.001). None of the patients, irrespective of group, returned to their pre-injury level of sport (P < 0.05). Over the five postoperative years, one man and eight women (13 %) (hamstring graft, n = 5 and BPTB graft, n = 4), sustained a total of 11 (16.2 %) new ACL ruptures: seven (10.2 %) re-ruptures and four (5.9 %) ruptures of the contralateral ACL. CONCLUSIONS: At the 5-year follow-up, there were no significant differences in terms of anterior knee laxity, rotational knee joint stability, muscle torque, anterior knee pain, hop performance, quality of life or activity level between patients who had undergone reconstruction with BPTB or hamstring grafts. None of the patients, irrespective of group, had returned to their pre-injury level of activity. Eight out of the nine patients who had sustained a second ACL rupture were women.

Oral contraceptives do not affect muscle strength and hop performance in active women.

OBJECTIVE: The primary aim of this study was to compare muscle strength in the upper and lower limb, as well as hop performance during oral contraceptive (OC) use with non-OC use in the same woman. A secondary aim was to compare muscle strength and hop performance within 3 specific phases of an OC cycle, as well as during a menstrual cycle of the corresponding cycle days (non-OC cycle). DESIGN: Crossover. SETTING: Research laboratory. PARTICIPANTS: Seventeen moderate to highly recreationally active women participated in the study. INTERVENTION: Observational study with no intervention. MAIN OUTCOME MEASURES: Maximal isokinetic muscle strength of knee extensors, isometric handgrip strength, and 1-leg hop test for distance were measured during 1 OC cycle and 1 non-OC cycle at 3 specific phases, respectively, using a crossover design. RESULTS: No significant differences were found in terms of muscle strength and hop performance between the OC cycle and the non-OC cycle. Furthermore, no significant difference in muscle strength and hop performance could be demonstrated within the OC cycle or within the phases of the menstrual cycle except from maximal isokinetic muscle strength in the knee extensors detected between the early follicular phase and the luteal phase. CONCLUSIONS: We found no support for any significant influence of OC use on muscle strength and hop performance in healthy moderately active women.

Responsiveness of the one-leg hop test and the square hop test to fatiguing intermittent aerobic work and subsequent recovery.

The purpose of the present study was to evaluate the responsiveness of the 1-leg hop test and the square hop (SH) test to fatiguing intermittent aerobic work and during recovery. A further aim was to study sex differences in trends. Members of 4 sub-elite-level soccer teams were invited to participate. Ten men (mean ± SD) aged 20.7 ± 3.4 years and 10 women aged 21.8 ± 4.8 years accepted to participate in the test. The Yo-Yo intermittent Endurance test Level 2, was used as a standardized sport-specific fatiguing protocol. The 1-leg hop test and the SH test were performed before, immediately after, 15, and 30 minutes after the fatiguing exercise. To quantify the level and progression of fatigue and recovery, blood lactate and heart rate were measured, and general fatigue was estimated on Borg's rating of perceived exertion scale. No significant difference in performance in either of the hop tests was found immediately after intermittent aerobic fatiguing work. Performance in the 1-leg hop test significantly decreased (p = 0.002), whereas that in the SH test increased (p = 0.001) between baseline and 15-30 minutes after fatiguing work. No significant difference in trends between sexes was found. The performance in the 1-leg hop test significantly decreased during 30 minutes of recovery compared with that in the nonfatigued conditions and might therefore be used on the field as a complement to other physical parameters to detect remaining fatigue. Note that the 1-leg hop test did not immediately respond to intermittent aerobic work. It is not recommended to use the SH test for measuring fatigue and subsequent recovery because the performance constantly increased despite the present objective and subjective fatigue.

Donor-site-related functional problems following anterior cruciate ligament reconstruction: development of a self-administered questionnaire.

PURPOSE: To develop a self-administered questionnaire for the evaluation of donor-site-related functional problems after anterior cruciate ligament (ACL) reconstruction with autograft harvested from the hamstring tendon or patellar tendon and to determine the content validity, reliability and preliminary factor structure of this new instrument. METHODS: Seven physiotherapists with long clinical experience of rehabilitation after ACL reconstruction and 60 patients from the target population participated as experts in the developmental stages of the questionnaire. Content validity was determined and quantified with the content validity index (CVI). Test-retest reliability, internal consistency and factor structure were evaluated in another 64 patients reconstructed with an autograft. RESULTS: The final questionnaire included 16 items on symptoms and function during activities of daily living and exercise. Excellent content validity on both item level (I-CVI ≥ 0.83, range 0.83-1.00) and scale level (S-CVI = 0.93) was found. The test-retest reliability was good, ICC = 0.94. Internal consistency was high, and Cronbach's α was 0.92 and 0.94 at each test occasion. The principal components analysis yielded a four-component structure. CONCLUSIONS: The questionnaire "Donor-site-Related Functional Problems following Anterior Cruciate Ligament (ACL) Reconstruction" is a patient-reported questionnaire with high content validity and reliability for the evaluation of donor-site-related functional problems after ACL reconstruction, with autograft harvested from the hamstring tendon or patellar tendon. The results of this study support the use of this questionnaire as a standardized outcome measure for both research purposes and in clinical settings.

Previous and current injury and not training and competition factors were associated with future injury prevalence across a season in adolescent elite athletes.

Introduction: Understanding the factors associated with different injury prevalence profiles in young athletes is needed for the design of tailored injury prevention programs.Objectives: To explore the factors associated with different levels of injury prevalence in adolescent elite athletes.Methods: A total of 389 adolescent elite athletes (age range 15-19 years), participating in 16 different sports, were monitored repeatedly over 52 weeks using the Oslo Sports Trauma Research Center Overuse Injury Questionnaire. The athletes were grouped in three injury categories: (1) "Low injury"; (2) "Medium injury"; and (3) "High injury," based on the proportion of times the athletes reported substantial injury over the season.Results: Logistic and multinomial regression identified substantial injury the first week (odds ratio (OR) 53.9, 95% confidence interval (CI) 7.1-407.7), and an interaction between sex and previous injury (OR 3.9, 95% CI 1.1-12.4) as significant factors that increased the odds of belonging in the High injury compared to the Low injury group. A female athlete with a previous injury the last 12 months had a higher probability of belonging in the High injury group compared to a male athlete.No significant (p > .05) difference in training, sleep, or competition exposure was found across the injury category.Conclusion: Current substantial injury and previous injury were strongly associated with the most injured athletes. Coaches and medical team should consider limiting the injured athlete competition exposure.

Subjective well-being is associated with injury risk in adolescent elite athletes.

Objective: The purpose of this study was to explore the association of subjective well-being with injury and injury severity in adolescent elite athletes.Design: Prospective cohort study.Participants: Three hundred eighty-six adolescent elite athletes (age range 15-19), participating in seven different sports, were monitored repeatedly over 52 weeks using a valid questionnaire about injuries, substantial injuries, injury severity and subjective well-being (scale 0-100).Results: A linear mixed model showed that subjective well-being was significantly influenced by injury severity (p < .001, estimate -1.7, 95% CI -1.4 to -2.0) and sex (p = .019, estimate -3.6, 95% CI -6.0 to -0.2). Of all injury reports where the athletes reported a well-being score of less than or equal to 20, 54% reported substantial injury, whereas 9% of the injury reports where the athletes reported a well-being score above 80 reported substantial injuries. In addition, an increase in subjective well-being with a score of 10 decreased the odds of injury with 5.6% (p = .036, 95% CI 89.5 to 99.6) and injury severity with 0.4 points (p = .01, 95% CI -0.6 to -0.1).Conclusion: Medical personnel need to be aware that young athletes may face well-being challenges while injured and that a low subjective well-being increase the injury risk the subsequent week.

Handball and movement screening - can non-contact injuries be predicted in adolescent elite handball players? A 1-year prospective cohort study.

Introduction: The nine-test screening battery (9SB) consists of 11 tests used to assess injury risk in sports populations.Objectives: To evaluate the predictive value of the composite score and underlying factors of the 9SB for sustaining non-contact injury in adolescent elite handball players.Methods: Forty-five (23 females) adolescent elite handball players, median age 17 (range 16-18), pre-seasonally performed the 9SB, followed by weekly recordings of injuries for 52 weeks using a web-based questionnaire.Results: The median value for seasonal substantial injury prevalence was 22% (25-75th percentiles 6-41). An exploratory factor analysis extracted three factors, complex movements, mobility, and lower extremity control, that explained a cumulative variance of 56%, where each factor contributed with 13-26% of the total variance. Based on the identified cutoff values, none of the factors or the complete 9SB could predict the risk of a non-contact new injury as well as the risk of reporting a substantial injury. Area under the curve values were ranged 0.50 to 0.59, with the corresponding 95% CI including 0.50 for all factors.Conclusion: Based on the limited predictive ability of the 9SB, it is not recommended that clinicians use the 9SB to predict injury in adolescent elite handball players.

A 2-year follow-up of rehabilitation after ACL reconstruction using patellar tendon or hamstring tendon grafts: a prospective randomised outcome study.

Sixty-eight patients were clinically evaluated preoperatively, 3, 5, 7, 9 months, 1 and 2 years after ACL reconstruction, 34 with patellar tendon graft, 34 with hamstring graft. Outcome regarding graft choice and anterior knee laxity (P = 0.04) was in favour of patellar tendon graft. Hamstring graft led to a larger laxity, 2.4 mm compared with patellar tendon graft, 1.3 mm at 1 year and 2.5 mm and 1.5 mm, respectively, at 2 years (P = 0.05). There was a significant difference in rotational knee stability in favour of the patellar tendon graft at all test occasions but 9 months. A general effect regarding graft choice and muscle torque was found at 90 degrees/s for quadriceps (P = 0.03) and hamstrings (P < or = 0.0001) and at 230 degrees/s for hamstrings (P < or = 0.0001). No treatment effect regarding graft choice and one-leg hop test, postural sway or knee function was found. No group differences in anterior knee pain were found at any of the test occasions but 2 years in favour of hamstring graft compared to patellar tendon graft (P = 0.04). Patellar tendon graft resulted in higher activity level than hamstring graft at all test occasions but 1 year (P = 0.01). Patellar tendon ACL reconstruction led to more stable knees with less anterior knee laxity and less rotational instability than hamstring ACL reconstruction. Hamstring graft patients had not reached preoperative level in hamstring torque even 2 years after ACL reconstruction. Athletes with patellar tendon graft returned to sports earlier and at a higher level than those with hamstring graft.

Can movement tests predict injury in elite orienteerers? An 1-year prospective cohort study.

The purpose of this study was to determine the predictive value of the movement test, the nine test screening battery (9TSB) and an orienteering-modified version of the 9TSB (M9TSB), for lower extremity injury in adolescent elite orienteerers. Design Prospective cohort study. Participants Forty adolescent (15-19 years), male and female orienteerers from two Swedish orienteering high schools performed the 9TSB, M9TSB, and recorded injuries based on a web-based questionnaire for 52 weeks. Results The results showed no difference in composite scores between injured and non-injured orienteerers for either 9TSB (p = 0.75) or M9TSB (p = 0.83). The optimal cut-off score was calculated at 25 for the 9TSB, with sensitivity and specificity of 74% and 41% respectively, and 17 for the M9TSB, with sensitivity and specificity of 47% and 61%, respectively. There was no association between 9TSB or M9TSB and injury (OR1.38, 95% CI: 0.39-4.92). Including athletes with a history of injury did not result in improved prediction of injury for the 9TSB or M9TSB (OR 2.84, 95% CI: 0.50-16.10). Conclusion Low sensitivity and specificity were obtained for both the M9TSB and the 9TSB. Thus, it is not recommended that physiotherapists use the nine test screening battery to predict lower extremity injury in orienteerers.

Does Early Functional Mobilization Affect Long-Term Outcomes After an Achilles Tendon Rupture? A Randomized Clinical Trial.

BACKGROUND: Functional deficits and health-related impairments are common after an Achilles tendon rupture (ATR). Rehabilitation protocols vary greatly, and few studies have allowed loading in combination with ankle motion immediately after surgery (ie, early functional mobilization [EFM]). It is unclear whether EFM may counteract the negative impact of ankle immobilization after an ATR. PURPOSE: The primary aim of this study was to assess the efficacy of EFM compared with standard treatment (ie, 2 weeks of unloading in a plaster cast followed by 4 weeks of weightbearing in an orthosis) regarding patient-reported and functional outcomes in patients with an ATR after acute operative repair. The secondary aim was to explore whether the occurrence of deep venous thrombosis (DVT) during the 2 postoperative treatments affected outcomes. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 135 patients who underwent ATR repair, randomized to either EFM, including immediate postoperative loading and ankle motion, or standard treatment, were evaluated with functional tests and 5 self-administered outcome questionnaires at 6 and 12 months postoperatively. RESULTS: At 6 months, the EFM group scored higher on the RAND 36-Item Health Survey (RAND-36) questionnaire subscales of general health and vitality (P < .05) compared with the control group. No significant differences between the groups were found on disease-specific questionnaires (Achilles tendon Total Rupture Score [ATRS] and Foot and Ankle Outcome Score [FAOS]). At 12 months, no significant differences on any of the patient-reported outcome measures or the functional heel-rise test were seen between the groups. The RAND-36 subscale of general health, however, exhibited higher values in the EFM group (82.6 ± 16.9) than the control group (77.1 ± 17.0) (P = .051) at 12 months after the injury. Patients sustaining DVT postoperatively had lower self-reported outcomes on the ATRS, FAOS, and RAND-36 questionnaires at 6 and 12 months compared with patients not having sustained DVT (all P < .05). CONCLUSION: This study demonstrated that an accelerated postoperative protocol with immediate loading and ankle motion resulted in better general health and vitality at 6 months. However, there were no differences between the groups in the recovery of heel-rise function. Future studies should focus on the means to reduce the risk of DVT to improve patient outcomes after ATR. REGISTRATION: NCT02318472 (ClinicalTrials.gov identifier).

Could specific exercises based on a movement screen prevent injuries in adolescent elite athletes?

OBJECTIVES: The primary aim of this study was to explore if specific exercises based on the nine test screening battery (9SB) reduce short-term and seasonal injury occurrence in adolescent elite athletes. SETTING: Youth elite sports. DESIGN: Prospective intervention study over 1-year. PARTICIPANTS: Adolescent elite athletes (n = 216) in age 15-20 from seven different sports. MAIN OUTCOME MEASURES: Seasonal/short-term injury incidence and seasonal substantial/injury prevalence was obtained via weekly surveys completed by study participants. RESULTS: There was a significant (p = 0.036) difference in the seasonal substantial injury prevalence across number of times the exercises were performed (exercise category), where athletes performing the exercises ≥4 times/week reported significantly (p = 0.048) higher seasonal substantial injury prevalence compared to athletes completing the exercises once a week (median 15.4 vs 0%, r = 0.25). No statistically significant difference in injury incidence (p = 0.429) or seasonal injury prevalence (p = 0.171) was found across exercise category. Performing the exercises once a day compared to not at all did not reduce the short-term risk of new injury or substantial injury. CONCLUSIONS: Our results provide supporting evidence that completing specific exercises based on the 9SB have no group effect on short-term or seasonal injury occurrence in adolescent elite athletes.

High Plantar Force Loading After Achilles Tendon Rupture Repair With Early Functional Mobilization.

BACKGROUND: Mechanical loading is essential for tendon healing and may explain variability in patient outcomes after Achilles tendon rupture (ATR) repair. However, there is no consensus regarding the optimal postoperative regimen, and the actual amount of loading during orthosis immobilization is unknown. PURPOSE: The primary aim of this study was to assess the number of steps and the amount of loading in a weightbearing orthosis during the first 6 weeks after surgical ATR repair. A secondary purpose was to investigate if the amount of loading was correlated to fear of movement and/or experience of pain. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirty-four patients (mean ± SD age, 38.8 ± 8.7 years) with ATR repair were included. Early functional mobilization was allowed postoperatively in an orthosis with adjustable ankle range of motion. During the first postoperative 2 weeks, patient-reported loading and pain were assessed with a visual analog scale and step counts with a pedometer. At the 2- and 6-week follow-up, a mobile force sensor was used for measuring plantar force loading, and the Tampa Scale for Kinesiophobia was used to examine fear of movement. RESULTS: Between the first and second weeks, there was a significant increase in the mean number of daily steps taken (from 2025 to 2753, P < .001) as well as an increase in self-reported loading (from 20% to 53%, P < .001). Patient self-reported loading was significantly associated with the plantar force measurement (rho = 0.719, P < .001). At 6 weeks, loading was 88.2% on the injured limb versus the uninjured limb. Fear of movement was not correlated with pedometer data, subjective loading, pain, or force data. Patients with less pain during activity, however, reported significantly higher subjective load and took more steps ( P < .05). CONCLUSION: This is the first study to demonstrate the actual loading patterns during postoperative functional mobilization among patients with surgically repaired ATR. The quick improvements in loading magnitude and frequency observed may reflect improved tendon loading essential for healing. Pain, rather than fear of movement, was associated with the high variability in loading parameters. The data of this study may be used to improve ATR rehabilitation protocols for future studies. REGISTRATION: NCT02318472 (ClinicalTrials.gov).

Correlates of health in adolescent elite athletes and adolescents: A cross-sectional study of 1016 adolescents.

The primary aim of this cross-sectional study was to compare subjective correlates of health, such as nutrition, self-esteem, sleep and stress, between adolescent elite athletes (n = 625) and a reference group of adolescents (n = 391) not involved in elite sports. A secondary aim was to study predictors for self-perceived stress. A questionnaire was e-mailed to all participants containing valid questions about competence-based self-esteem, nutrition, self-perceived stress and sleep. Our results show that adolescent elite athletes reported significantly (p < .001) lower self-perceived stress, competence-based self-esteem, a more varied diet and more time of sleep, compared to adolescents not involved in elite sports (Hedges'g 0.31-0.82). Female adolescent elite athletes and female adolescents, compared to their male peer group, reported poorer values for competence-based self-esteem (elite, Hedges'g 0.29; adolescents, Hedges'g 0.30) and self-perceived stress (elite, Hedges'g 0.63; adolescents, Hedges'g 0.60). The linear mixed effect model revealed several significant (p < .05) predictors (sex, general well-being, competence-based self-esteem, sleep during weekdays, BMI, training volume) associated with self-perceived stress in adolescent elite athletes. In conclusion, differences in correlates of health with a moderate to strong effect sizes were found between the two groups, where elite athletes surprisingly reported less stress, competence-based self-esteem, a more varied diet and more time of sleep. Even if injury risk is high in adolescent elite athletes and pressure from multiple stakeholders is evident, it appears that the athletes still have better conditions for a good subjective health, based on self-reported measures, compared to adolescents not involved in elite sports.

High Injury Burden in Elite Adolescent Athletes: A 52-Week Prospective Study.

CONTEXT: Our understanding of the injury burden in elite adolescent athletes in most sports is limited or unknown because of the lack of prospective, long-term injury studies. OBJECTIVE: To describe injury patterns in terms of type, location, prevalence and incidence, recurrence, and severity grade; time to first injury; and prevalence of illness in elite adolescent athletes and to compare differences in injury data by sex and sport type. DESIGN: Cohort study. SETTING: Fifteen national sports high schools in Sweden. PATIENTS OR OTHER PARTICIPANTS: Participants were 284 elite adolescent athletes (boys = 147, girls = 137; median age = 17 years; 25th-75th percentile range = 16-18 years) competing at a high national level for their age in athletics (track and field), cross-country skiing, downhill skiing, freestyle skiing, handball, orienteering, or ski orienteering. MAIN OUTCOME MEASURE(S): All athletes were monitored weekly over 52 weeks, using a validated online questionnaire to identify injury type, location, prevalence or incidence, and severity grade; time to first injury; and prevalence of illness. RESULTS: Among all athletes, 57.4% reported at least 1 new injury, whereas the 1-year injury prevalence was 91.6%. The overall injury incidence was 4.1/1000 hours of exposure to sport, and every week, on average, 3 of 10 (30.8%) elite adolescent athletes reported being injured. Of all injuries from which athletes recovered, 22.2% (n = 35) resulted in absence from normal training for at least 2 months. Female athletes reported higher ( P < .05) average weekly injury prevalence and substantial injury prevalence (injuries leading to a moderate or severe reduction in sport performance or participation or time loss) than male athletes. CONCLUSIONS: A considerable number of elite adolescent athletes were injured weekly, resulting in serious consequences for sport participation, training, or performance (or a combination of these). Appropriately designed interventions to prevent knee and foot injuries will target both the greatest number of injuries and the injuries with the most serious consequences in elite adolescent athletes.

Young, talented and injured: Injury perceptions, experiences and consequences in adolescent elite athletes.

Even though injury is common in elite sports, there is still a lack of knowledge of young athletes' injury perception both during and after injury. The aim of this mixed-method study was, therefore, to explore, in-depth, data on injury consequences and adolescent elite athletes' perceptions and experience of injury. Three hundred and forty adolescent elite athletes (age range 15-19), from 16 different sports, were bi-weekly monitored over 52 weeks using a valid questionnaire. Twenty athletes from the same cohort were interviewed in focus groups about injury experience and perceptions. The results show that the average bi-weekly prevalence of injury was 38.7% (95% CI 37.3-40.1), with 30.0% (n = 102) of the athletes injured for more than half of all reporting times. An overarching theme from the focus groups highlighted the risk among young athletes of a loss of identity while injured. The findings support several suggestions that may improve the rehabilitation process and enhance rehabilitation outcomes: (a) provide clear pathways to the medical team, (b) recognize the identity loss, (c) involve the injured athletes with the rest of the teammates and (d) educate athletes about how to interpret pain signals. Future research should explore and evaluate the effectiveness and generalization of such interventions.

How does exercise dose affect patients with long-term osteoarthritis of the knee? A study protocol of a randomised controlled trial in Sweden and Norway: the SWENOR Study.

INTRODUCTION: Osteoarthritis (OA) of the knee is characterised by knee pain, disability and degenerative changes, and places a burden on societies all over the world. Exercise therapy is an often-used modality, but there is little evidence of what type of exercise dose is the most effective, indicating a need for controlled studies of the effect of different dosages. Thus, the aim of the study described in this protocol is to evaluate the effects of high-dose versus low-dose medical exercise therapy (MET) in patients with knee OA. METHODS AND ANALYSIS: This is a multicentre prospective randomised two-arm trial with blinded assessment and data analysis. We are planning to include 200 patients aged 45-85 years with symptomatic (pain and decreased functioning) and X-ray verified diagnosis of knee OA. Those eligible for participation will be randomly allocated to either high-dose (n=100) or low-dose (n=100) MET. All patients receive three supervised treatments each week for 12 weeks, giving a total of 36 MET sessions. The high-dose group exercises for 70-90 min compared with 20-30 min for the low-dose group. The high-dose group exercises for a longer time, and receives a greater number of exercises with more repetitions and sets. Background and outcome variables are recorded at inclusion, and outcome measures are collected after every sixth treatment, at the end of treatment, and at 6-month and 12-month follow-ups. Primary outcome is self-rated knee functioning and pain using the Knee Injury and Osteoarthritis Outcome Score (KOOS). The primary end point is at the end of treatment after 3 months, and secondary end points are at 6 months and 12 months after the end of treatment. ETHICS AND DISSEMINATION: This project has been approved by the Regional Research Ethics Committees in Stockholm, Sweden, and in Norway. Our results will be submitted to peer-reviewed journals and presented at national and international conferences. TRIAL REGISTRATION NUMBER: NCT02024126; Pre-results.

How should we categorise self-reported data on subsequent injuries?

Classifying subsequent injuries is of high importance in injury epidemiology since a previous injury has been reported to increase the risk of a new injury or increase the risk of a more severe injury. Multiple reports have shown that self-reported data provide an extensive view of an injury problem and add valuable information to the understanding of the athlete's health. The purpose of this study was to display a method that can be used to facilitate classification of subsequent injuries and to discuss challenges faced when categorising subsequent injuries based on self-reported data. The suitability of a new model for Subsequent Injuries Adjusted for Self-reported data (SIAS model) was demonstrated with sport injury data from a cohort of 101 adolescent elite track & field athletes, followed over 52 weeks. A total number of 71 subsequent injuries were identified. Of all subsequent injuries, recurrent injuries represented 69.0% (n = 49) and 31.0% (n = 22) were classified as new injuries. The majority of subsequent injuries (n = 60, 84.5%) occurred after athletes had recovered from a previous injury. Of all subsequent injuries, 15.5% (n = 11) represented injuries where athletes had not fully recovered from a previous injury. Application of the SIAS model allows for classification of subsequent injuries based on self-reported data on the recovery level of the athletes, the injury onset and injury type. The developed SIAS model follows the consensus recommendations of injury definition, injury classification and is an attempt to increase the understanding of the complex relationship of subsequent injuries in self-reported data sets.

INJURY PATTERNS IN ADOLESCENT ELITE ENDURANCE ATHLETES PARTICIPATING IN RUNNING, ORIENTEERING, AND CROSS-COUNTRY SKIING.

BACKGROUND: Prospective injury registration studies, monitoring adolescent elite athletes, are sparse in running, orienteering and cross-country skiing, yet essential for developing prevention programs. PURPOSE: The aims of this study were to describe the injury prevalence/incidence, severity grade, injury location, risk factors and the prevalence of illness in running (RU), orienteering (OR) and cross-country skiing athletes (CR). STUDY DESIGN: Prospective cohort study. METHODS: One hundred fifty adolescent elite athletes (age range 16-19), participating in orienteering (25 females, 20 males), running (13 females, 18 males), cross-country skiing (38 females, 36 males), from 12 National Sports High Schools in Sweden, were prospectively followed over one calendar year using a reliable and validated web-based questionnaire. RESULTS: The main finding was that the average weekly injury prevalence was higher during the pre-season compared to the competitive season in all three sports. RU reported the significantly (p<0.05) highest average weekly injury prevalence (32.4%) and substantial injury prevalence (17.0%), compared to OR (26.0, 8.2%) and CR (21.1%, 8.9%). Most injuries occurred in the lower extremity (RU 94.4%; OR 91.9%; CR 49.9%) and foot and knee injuries had the highest severity grade in all three sports. History of serious injury (p=0.002, OR 4.0, 95% CI 1.6-9.7) and current injury at study start (p=0.004, OR 4.0, 95% CI 1.5-11.2) were identified as the strongest risk factors for substantial injury. Younger athletes aged 16 (p=0.019, OR 2.6, 95% CI 1.2-5.8) and 17 (p=0.045, OR 2.4, 95% CI 1.0-5.9), had a significantly higher injury risk for substantial injury compared to older athletes aged 18-19. CONCLUSION: Practitioners should be aware of the increased injury risk during pre-season and in younger athletes. By focus on prevention of foot and knee injuries, the injuries with the highest severity grade will be targeted in adolescent elite athletes participating in running, orienteering and cross-country skiing. LEVEL OF EVIDENCE: 2b.