R-miniCHOP versus R-CHOP in elderly patients with diffuse large B-cell lymphoma: A propensity matched population-based study.

For elderly frail patients with diffuse large B-cell lymphoma (DLBCL), an attenuated chemo-immunotherapy strategy of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-miniCHOP) was introduced as a treatment option as from 2014 onward in the Netherlands. Although R-miniCHOP is more tolerable, reduction of chemotherapy could negatively affect survival compared to R-CHOP. The aim of this analysis was to assess survival of patients treated with R-miniCHOP compared to R-CHOP. DLBCL patients ≥65 years, newly diagnosed in 2014-2020, who received ≥1 cycle of R-miniCHOP or R-CHOP were identified in the Netherlands Cancer Registry, with survival follow-up through 2022. Patients were propensity-score-matched for baseline characteristics. Main endpoints were progression-free survival (PFS), overall survival (OS), and relative survival (RS). The use of R-miniCHOP in DLBCL increased from 2% in 2014 to 15% in 2020. In total, 384 patients treated with R-miniCHOP and 384 patients treated with R-CHOP were included for comparison (median age; 81 years, stage 3-4; 68%). The median number of R-(mini)CHOP cycles was 6 (range, 1-8). The 2-year PFS, OS and RS were inferior for patients treated with R-miniCHOP compared to R-CHOP (PFS 51% vs. 68%, p < .01; OS 60% vs. 75%, p < .01; RS 69% vs. 86%, p < .01). In multivariable analysis, patients treated with R-miniCHOP had higher risk of all-cause mortality compared to patients treated with R-CHOP (HR 1.73; 95%CI, 1.39-2.17). R-miniCHOP is effective for most elderly patients. Although survival is inferior compared to R-CHOP, the use of R-miniCHOP as initial treatment is increasing. Therefore, fitness needs to be carefully weighed in treatment selection.

Development of pancreatic diseases during long-term follow-up after acute pancreatitis: a post-hoc analysis of a prospective multicenter cohort.

BACKGROUND AND AIM: More insight into the incidence of and factors associated with progression following a first episode of acute pancreatitis (AP) would offer opportunities for improvements in disease management and patient counseling. METHODS: A long-term post hoc analysis of a prospective cohort of patients with AP (2008-2015) was performed. Primary endpoints were recurrent acute pancreatitis (RAP), chronic pancreatitis (CP), and pancreatic cancer. Cumulative incidence calculations and risk analyses were performed. RESULTS: Overall, 1184 patients with a median follow-up of 9 years (IQR: 7-11) were included. RAP and CP occurred in 301 patients (25%) and 72 patients (6%), with the highest incidences observed for alcoholic pancreatitis (40% and 22%). Pancreatic cancer was diagnosed in 14 patients (1%). Predictive factors for RAP were alcoholic and idiopathic pancreatitis (OR 2.70, 95% CI 1.51-4.82 and OR 2.06, 95% CI 1.40-3.02), and no pancreatic interventions (OR 1.82, 95% CI 1.10-3.01). Non-biliary etiology (alcohol: OR 5.24, 95% CI 1.94-14.16, idiopathic: OR 4.57, 95% CI 2.05-10.16, and other: OR 2.97, 95% CI 1.11-7.94), RAP (OR 4.93, 95% CI 2.84-8.58), prior pancreatic interventions (OR 3.10, 95% CI 1.20-8.02), smoking (OR 2.33, 95% CI 1.14-4.78), and male sex (OR 2.06, 95% CI 1.05-4.05) were independently associated with CP. CONCLUSION: Disease progression was observed in a quarter of pancreatitis patients. We identified several risk factors that may be helpful to devise personalized strategies with the intention to reduce the impact of disease progression in patients with AP.

River Basin Export Reduction Optimization Support Tool; a tool to screen options for reducing nutrient loads while minimizing cost.

Excess loading of nitrogen and phosphorus to river networks causes environmental harm, but reducing loads from large river basins is difficult and expensive. We develop a new tool, the River Basin Export Reduction Optimization Support Tool (RBEROST) to identify least-cost combinations of management practices that will reduce nutrient loading to target levels in downstream and mid-network waterbodies. We demonstrate the utility of the tool in a case study in the Upper Connecticut River basin in New England, USA. The total project cost of optimized lowest-cost plans ranged from $18.0 million to $41.0 million per year over 15 years depending on user specifications. Plans include both point source and non-point source management practices, and most costs are associated with urban stormwater practices. Adding a 2% margin of safety to loading targets improved estimated probability of success from 37.5% to 99%. The large spatial scale of RBEROST, and the consideration of both point and non-point source contributions of nutrients, makes it well suited as an initial screening tool in watershed planning.

Real-time non-adiabatic dynamics in the one-dimensional Holstein model: Trajectory-based vs exact methods.

We benchmark a set of quantum-chemistry methods, including multitrajectory Ehrenfest, fewest-switches surface-hopping, and multiconfigurational-Ehrenfest dynamics, against exact quantum-many-body techniques by studying real-time dynamics in the Holstein model. This is a paradigmatic model in condensed matter theory incorporating a local coupling of electrons to Einstein phonons. For the two-site and three-site Holstein model, we discuss the exact and quantum-chemistry methods in terms of the Born-Huang formalism, covering different initial states, which either start on a single Born-Oppenheimer surface, or with the electron localized to a single site. For extended systems with up to 51 sites, we address both the physics of single Holstein polarons and the dynamics of charge-density waves at finite electron densities. For these extended systems, we compare the quantum-chemistry methods to exact dynamics obtained from time-dependent density matrix renormalization group calculations with local basis optimization (DMRG-LBO). We observe that the multitrajectory Ehrenfest method, in general, only captures the ultrashort time dynamics accurately. In contrast, the surface-hopping method with suitable corrections provides a much better description of the long-time behavior but struggles with the short-time description of coherences between different Born-Oppenheimer states. We show that the multiconfigurational Ehrenfest method yields a significant improvement over the multitrajectory Ehrenfest method and can be converged to the exact results in small systems with moderate computational efforts. We further observe that for extended systems, this convergence is slower with respect to the number of configurations. Our benchmark study demonstrates that DMRG-LBO is a useful tool for assessing the quality of the quantum-chemistry methods.

Ammonia concentrations, litter quality, performance and some welfare parameters of broilers kept on different bedding materials.

1. Litter quality has been related to broiler performance, behaviour, welfare, dust and ammonia (NH3) emissions. Drier litter leads to a reduction in NH3 emissions and reduces the formation of foot- and hock lesions. However, maintaining good litter quality is often challenging. This study investigated the effects of different bedding materials on litter quality and NH3 concentrations at litter level, broiler performance, foot- and hock lesions, plumage cleanliness and breast skin irritation.2. A total of 2160 Ross 308 male broilers were randomly assigned to 36 floor pens. There were six replications for each of the following six litter treatments: wood shavings, flax, peat, maize silage, chopped wheat straw and flax pellets.3. For the total period, the highest feed intake and body weight was obtained for broilers housed on peat. The NH3 concentrations measured at litter level was highest for peat and chopped wheat straw at 36 d of age and numerically the lowest for flax at 30 and 36 d of age. Maize silage remained friable, but did not result in lower NH3 concentrations compared to wood shavings. Chopped wheat straw and wood shavings gave rise to the highest incidence of foot lesions at 38 d of age, while broilers kept on flax, peat, maize silage and flax pellets had the lowest incidence of foot lesions at the end of the rearing period.4. The results of the current study suggest a complicated relationship between the type of bedding material, litter conditions and NH3 volatilised from the litter.

The levonorgestrel intrauterine system versus endometrial ablation for heavy menstrual bleeding: a cost-effectiveness analysis.

OBJECTIVE: To evaluate the costs and non-inferiority of a strategy starting with the levonorgestrel intrauterine system (LNG-IUS) compared with endometrial ablation (EA) in the treatment of heavy menstrual bleeding (HMB). DESIGN: Cost-effectiveness analysis from a societal perspective alongside a multicentre randomised non-inferiority trial. SETTING: General practices and gynaecology departments in the Netherlands. POPULATION: In all, 270 women with HMB, aged ≥34 years old, without intracavitary pathology or wish for a future child. METHODS: Randomisation to a strategy starting with the LNG-IUS (n = 132) or EA (n = 138). The incremental cost-effectiveness ratio was estimated. MAIN OUTCOME MEASURES: Direct medical costs and (in)direct non-medical costs were calculated. The primary outcome was menstrual blood loss after 24 months, measured with the mean Pictorial Blood Assessment Chart (PBAC)-score (non-inferiority margin 25 points). A secondary outcome was successful blood loss reduction (PBAC-score ≤75 points). RESULTS: Total costs per patient were €2,285 in the LNG-IUS strategy and €3,465 in the EA strategy (difference: €1,180). At 24 months, mean PBAC-scores were 64.8 in the LNG-IUS group (n = 115) and 14.2 in the EA group (n = 132); difference 50.5 points (95% CI 4.3-96.7). In the LNG-IUS group, 87% of women had a PBAC-score ≤75 points versus 94% in the EA group (relative risk [RR] 0.93, 95% CI 0.85-1.01). The ICER was €23 (95% CI €5-111) per PBAC-point. CONCLUSIONS: A strategy starting with the LNG-IUS was cheaper than starting with EA, but non-inferiority could not be demonstrated. The LNG-IUS is reversible and less invasive and can be a cost-effective treatment option, depending on the success rate women are willing to accept. TWEETABLE ABSTRACT: Treatment of heavy menstrual bleeding starting with LNG-IUS is cheaper but slightly less effective than endometrial ablation.

Effectiveness of a Tailored Work-Related Support Intervention for Patients Diagnosed with Gastrointestinal Cancer: A Multicenter Randomized Controlled Trial.

Purpose The aim of this research was to study the effectiveness on return to work (RTW) of an early tailored work-related support intervention in patients diagnosed with curative gastrointestinal cancer. Methods A multicenter randomized controlled trial was undertaken, in which patients were assigned randomly to the intervention or the control group (usual care). The intervention encompassed three psychosocial work-related support meetings, starting before treatment. Five self-reported questionnaires were sent over twelve months of follow-up. Primary outcome was days until RTW (fulltime or partial) and secondary outcomes included work status, quality of life, work ability, and work limitations. Descriptive analysis, Kaplan-Meier analysis, relative risk ratio and linear mixed models were applied. Results Participants (N = 88) had a mean age of 55 years; 67% were male and the most common cancer type was colon cancer (66%). Of the participants, 42 were randomized to the intervention group. The median time from sick leave until RTW was 233 days (range 187-279 days) for the control group, versus 190 days (range 139-240 days) for the intervention group (log-rank p = 0.37). The RTW rate at twelve months after baseline was 83.3% for the intervention group and 73.5% for the control group. Work limitations did statistically differ between the groups over time (p = 0.01), but quality of life and work ability did not. Conclusion Patients in the intervention group seem to take fewer days to RTW, albeit not to a statistically significant extent.Trial registration Trial NL4920 (NTR5022) (Dutch Trial Register https://www.trialregister.nl ).

Secretory antibodies to citrullinated peptides in plasma and saliva from rheumatoid arthritis patients and their unaffected first-degree relatives.

The aim of this study was to evaluate secretory antibodies to citrullinated proteins (ACPA) in plasma and immunoglobulin (Ig)A ACPA in saliva from patients with rheumatoid arthritis (RA) and their unaffected first-degree relatives (FDRs). Patients with RA (n = 194) and first-degree relatives unaffected by RA (n = 191) were recruited for analysis of secretory antibodies to second-generation cyclic citrullinated peptides (anti-CCP) in plasma. From a subpopulation (25 RA patients, 21 first-degree relatives and 11 controls), saliva samples were obtained for IgA anti-CCP analysis. The presence of secretory ACPA was compared between subject categories, and related to genetic and environmental risk factors. Secretory ACPA occurred in 37 (19%) plasma samples from patients with RA, but only in two (1%) of FDRs. IgA ACPA in saliva was found in three of 25 (12%) patients with RA, but not in any of the 21 FDRs (< 5%). No significant associations were seen between the presence of secretory ACPA and SE or smoking, either among RA patients or among FDRs. Despite occurring in 19% of RA plasma, secretory ACPA was rare in both saliva and plasma among FDRs, even among those positive for conventional ACPA of non-mucosal origin. Longitudinal studies are warranted to determine whether circulating secretory ACPA occurs before or in parallel with the development of clinical arthritis.

Rapid on-site evaluation during endoscopic ultrasound-guided fine-needle aspiration of lymph nodes does not increase diagnostic yield: A randomized, multicenter trial.

OBJECTIVES: Studies on the impact of rapid on-site evaluation (ROSE) during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of lymph nodes are retrospective and have shown conflicting results. We aimed to compare the diagnostic yield of EUS-FNA of lymph nodes with ROSE (ROSE+) and without ROSE (ROSE-). METHODS: This was a multicenter, randomized controlled trial. Consecutive patients who were scheduled to undergo EUS-FNA of mediastinal or abdominal lymph nodes were randomized to ROSE+ or ROSE-. In the ROSE+ group, the number of passes was dictated by the on-site cytotechnician. In the ROSE- group, five passes were performed without interference from the cytotechnician. All samples were reviewed by a single-expert cytopathologist, blinded to group allocation. Primary endpoint was diagnostic yield with and without ROSE. RESULTS: After inclusion of 90 patients, interim analysis showed futility of study continuation since diagnostic yield of ROSE+ and ROSE- were comparable. A total of 91 patients were randomized to ROSE+ (N = 45) or ROSE- (N = 46). Diagnostic yield of ROSE+ and ROSE- and diagnostic accuracy were comparable: 93.3% vs. 95.7% (P = 0.68) and 97.6% vs. 93.2% (P = 0.62), respectively. Two major complications (one per group) occurred (p = 0.99). ROSE- patients more often reported self-limiting post-procedural pain (p < 0.001). Median procedure time for ROSE+ (20 min) and ROSE- (23 min) was comparable (P = 0.06). Median time to review slides in the ROSE- group (12:47 min) was longer than with ROSE+ (7:52 min) (P < 0.001). Mean costs of ROSE- and ROSE+ were comparable: €938.29 (±172.70) vs. €945.98 (±223.38) (P = 0.91), respectively. CONCLUSIONS: Diagnostic yield and accuracy of EUS-FNA of mediastinal and abdominal lymph nodes with and without ROSE are comparable. Time needed to review slides was shorter and post-procedural pain was less often reported in the ROSE+ group. Based on the primary outcome, the implementation of ROSE during EUS-FNA of mediastinal and abdominal lymph nodes cannot be advised. (Dutch Trial Register: NTR4876).

Imatinib treatment of poor prognosis mesenchymal-type primary colon cancer: a proof-of-concept study in the preoperative window period (ImPACCT).

BACKGROUND: The identification of four Consensus Molecular Subtypes (CMS1-4) of colorectal cancer forms a new paradigm for the design and evaluation of subtype-directed therapeutic strategies. The most aggressive subtype - CMS4 - has the highest chance of disease recurrence. Novel adjuvant therapies for patients with CMS4 tumours are therefore urgently needed. CMS4 tumours are characterized by expression of mesenchymal and stem-like genes. Previous pre-clinical work has shown that targeting Platelet-Derived Growth Factor Receptors (PDGFRs) and the related KIT receptor with imatinib is potentially effective against mesenchymal-type colon cancer. In the present study we aim to provide proof for the concept that imatinib can reduce the aggressive phenotype of primary CMS4 colon cancer. METHODS: Tumour biopsies from patients with newly diagnosed stage I-III colon cancer will be analysed with a novel RT-qPCR test to pre-select patients with CMS4 tumours. Selected patients (n = 27) will receive treatment with imatinib (400 mg per day) starting two weeks prior to planned tumour resection. To assess treatment-induced changes in the aggressive CMS4 phenotype, RNA sequencing will be performed on pre- and post-treatment tissue samples. DISCUSSION: The development of effective adjuvant therapy for primary colon cancer is hindered by multiple factors. First, new drugs that may have value in the prevention of (early) distant recurrence are almost always first tested in patients with heavily pre-treated metastatic disease. Second, measuring on-target drug effects and biological consequences in tumour tissue is not commonly a part of the study design. Third, due to the lack of patient selection tools, clinical trials in the adjuvant setting require large patient populations. Finally, the evaluation of recurrence-prevention requires a long-term follow-up. In the ImPACCT trial these issues are addressed by including newly diagnosed pre-selected patients with CMS4 tumours prior to primary tumour resection, rather than non-selected patients with late-stage disease. By making use of the pre-operative window period, the biological effect of imatinib treatment on CMS4 tumours can be rapidly assessed. Delivering proof-of-concept for drug action in early stage disease should form the basis for the design of future trials with subtype-targeted therapies in colon cancer patients. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02685046 . Registration date: February 9, 2016.

Is risk-taking in talented junior tennis players related to overuse injuries?

Overuse injuries are a serious problem in junior tennis. Gaining insight in age-specific risk factors can contribute to prevention. The developmental cognitive processes that take place during adolescence make talented players more inclined to take risks. This may be even more pronounced in the high performance culture in which they move. Therefore, this study focuses on the relationship between risk-taking and overuse injuries in talented tennis players. Seventy-three talented tennis players (45 boys and 28 girls, age 11-14 years) were monitored for 32 weeks, using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems. Risk-taking was measured at the start of the season with the Iowa Gambling Task. Linear regression analyses were executed to predict (a) overuse injuries, (b) time loss overuse injuries and (c) overuse severity, by risk-taking, exposure time, and injury history. In boys, risk-taking contributed significantly to time loss overuse injuries [F(1,39) = 7.764, P = 0.008, R2  = 0.15] and to overuse severity [F(1,39) = 5.683, P = 0.022, with an R2 of 0.13] In girls, time loss overuse injuries [F(1,23) = 6.889, P = 0.018, R2  = 0.20] and overuse severity [F(1,23) = 7.287, P = 0.013, R2  = 0.24] were predicted by exposure time. Coaches and trainers should be aware that talented male tennis players who are inclined to take risks, are more likely to maintain risky behavioral patterns related to overuse injuries.

The preventive effect of the bounding exercise programme on hamstring injuries in amateur soccer players: the design of a randomized controlled trial.

BACKGROUND: Hamstring injuries are the most common muscle injury in amateur and professional soccer. Most hamstring injuries occur in the late swing phase, when the hamstring undergoes a stretch-shortening cycle and the hamstring does a significant amount of eccentric work. The incidence of these injuries has not decreased despite there being effective injury prevention programmes focusing on improving eccentric hamstring strength. As this might be because of poor compliance, a more functional injury prevention exercise programme that focuses on the stretch-shortening cycle might facilitate compliance. In this study, a bounding exercise programme consisting of functional plyometric exercises is being evaluated. METHODS: A cluster-randomized controlled trial (RCT). Male amateur soccer teams (players aged 18-45 years) have been randomly allocated to intervention and control groups. Both groups are continuing regular soccer training and the intervention group is additionally performing a 12-week bounding exercise programme (BEP), consisting of a gradual build up and maintenance programme for the entire soccer season. The primary outcome is hamstring injury incidence. Secondary outcome is compliance with the BEP during the soccer season and 3 months thereafter. DISCUSSION: Despite effective hamstring injury prevention programmes, the incidence of these injuries remains high in soccer. As poor compliance with these programmes may be an issue, a new plyometric exercise programme may encourage long-term compliance and is expected to enhance sprinting and jumping performance besides preventing hamstring injuries. TRIAL REGISTRATION: NTR6129 . Retrospectively registered on 1 November 2016.

Jump Landing Characteristics Predict Lower Extremity Injuries in Indoor Team Sports.

The aim of this study is to investigate the predictive value of landing stability and technique to gain insight into risk factors for ankle and knee injuries in indoor team sport players. Seventy-five male and female basketball, volleyball or korfball players were screened by measuring landing stability after a single-leg jump landing and landing technique during a repeated counter movement jump by detailed 3-dimensional kinematics and kinetics. During the season 11 acute ankle injuries were reported along with 6 acute and 7 overuse knee injuries by the teams' physical therapist. Logistic regression analysis showed less landing stability in the forward and diagonal jump direction (OR 1.01-1.10, p≤0.05) in players who sustained an acute ankle injury. Furthermore landing technique with a greater ankle dorsiflexion moment increased the risk for acute ankle injury (OR 2.16, p≤0.05). A smaller knee flexion moment and greater vertical ground reaction force increased the risk of an overuse knee injury (OR 0.29 and 1.13 respectively, p≤0.05). Less one-legged landing stability and suboptimal landing technique were shown in players sustaining an acute ankle and overuse knee injury compared to healthy players. Determining both landing stability and technique may further guide injury prevention programs.

Monitoring Perceived Stress and Recovery in Relation to Cycling Performance in Female Athletes.

The purpose was to investigate perceived stress and recovery related to cycling performance of female athletes over one full year. 20 female athletes (age, 27±8 years; ˙VO2max, 50.3±4.6 mL·kg(-1)·min(-1)) were measured 8 times in one year to determine perceived stress and recovery (RESTQ-Sport) in relation to cycling performance (Lamberts and Lambert Submaximal Cycle Test (LSCT)). All 19 RESTQ-Sport scales were calculated and scores of the 4 main categories were determined (i. e., general stress, general recovery, sport-specific stress and sport-specific recovery). A balance score of total stress and recovery was calculated by recovery-stress. Power at the second stage (P80), third stage (P90) and heart rate recovery (HRR60 s) of the LSCT were determined as performance parameters. 110 RESTQ-Sports and LSCTs were analysed using a multilevel approach (random intercepts model). Higher self-efficacy was related to improvement of all performance parameters. Higher total recovery stress, and lower emotional stress were related to improvement of P90 and HRR60 s. Higher sport-specific recovery was related to P80, higher general stress, fatigue and physical complaints were related to decreased P90 and higher social stress and injury were related to decreased HRR60 s. Improved perceived recovery and stress contributed to an improved performance. Relevant information could be provided by monitoring changes in perceived stress and recovery of female athletes.

Prospective Study of the Relation between Landing Biomechanics and Jumper's Knee.

The literature on the relation between jump biomechanics and jumper's knee indicates that a jump with horizontal displacement poses a threat for developing jumper's knee. Subjects with jumper's knee have been shown to display a stiff landing pattern characterized by a small range of motion. However, up to now only cross-sectional studies have been conducted. 6 teams from sports involving repetitive landing were followed prospectively for 2 years. At baseline athletes performed the Landing Error Scoring System jump and 3D kinematics and kinetics were obtained. A comparison was made between subjects who developed jumper's knee and those who did not develop it. 3 subjects developed jumper's knee during the study. Leg stiffness during landing was high compared to the mean of the healthy controls. No common kinematic patterns could be identified in these 3 subjects. The results suggest that athletes with high leg stiffness during landing might have an increased risk for developing jumper's knee, yet this conclusion is based on a very small sample. Subjects who develop jumper's knee do not show a common landing technique. Further research is needed to investigate whether leg stiffness can be used to identify athletes at risk and as a target variable to be used in prevention.

A Negative Life Event Impairs Psychosocial Stress, Recovery and Running Economy of Runners.

The purpose was to investigate how a negative life event (NLE) affects perceived psychosocial stress, recovery and running economy (RE). Competitive runners were monitored in a prospective non-experimental cohort study over one full training season in which they experienced the same unplanned severe NLE. 16 runners recorded stress and recovery scores (RESTQ-Sport) every week. The average scores over 3 weeks before the NLE were used as a baseline and were compared to scores during the week of the NLE (week 0), week 1 and week 2. 7 runners completed a submaximal treadmill test before and after the NLE. Repeated measures ANOVAs revealed that most scores on general stress scales were increased in week 0 and 1. Of the general recovery scales, "general well-being" was decreased in week 0 and 1, "social" and "physical recovery" were decreased in week 0. No changes in the sport-specific stress scales were found. However, 2 of the sport-specific recovery scales were decreased in week 0. An impaired RE was shown 3 weeks after the NLE. Therefore, it is important to know what is going on in an athlete's life, because stressful life events alter RE after the stress and recovery already returned to normal levels.

Importance of peak height velocity timing in terms of injuries in talented soccer players.

The purpose of this study was to identify differences in traumatic and overuse injury incidence between talented soccer players who differ in the timing of their adolescent growth spurt. 26 soccer players (mean age 11.9 ± 0.84 years) were followed longitudinally for 3 years around Peak Height Velocity, calculated according to the Maturity Offset Protocol. The group was divided into an earlier and later maturing group by median split. Injuries were registered following the FIFA consensus statement. Mann-Whitney tests showed that later maturing players had a significantly higher overuse injury incidence than their earlier maturing counterparts both in the year before Peak Height Velocity (3.53 vs.0.49 overuse injuries/1 000 h of exposure,U = 49.50, z = − 2.049, p < 0.05) and the year of Peak Height Velocity (3.97 vs. 1.56 overuse injuries/1 000 h of exposure, U = 50.5, z = − 1.796,p < 0.05). Trainers and coaches should be careful with the training and match load they put on talented soccer players, especially those physically not (yet) able to handle that load. Players appear to be especially susceptible to injury between 13.5 and 14.5 years of age. Training and match load should be structured relative to maturity such that athletic development is maximized and the risk of injury is minimized.

Anthropometric Injury Risk Factors in Elite-standard Youth Soccer.

The aim of the study was to investigate whether an increased risk of injury occurrence can be determined through frequent anthropometric measurements in elite-standard youth soccer players. Over the course of one season, we followed 101 male elite-standard youth soccer players between 11 and 19 years of age. Height and body mass were monitored at monthly measurement intervals and fat percentage was assessed every 3 months by use of the sum of skinfold method. Growth in height (cm), alternations in body mass index (kg/m(2)), fat percentage and fat-free mass index (kg/m(2)) were calculated. Injuries were recorded in accordance with the recommendations of the FIFA Consensus Model for Injury Registration. Odds ratio scores and 95% confidence intervals were calculated using binary logistic regression analyses. The following anthropometric injury risk factors were identified: ≥ 0.6 centimeter growth per month (p=0.03; OR=1.63; 95% CI: 1.06-2.52), ≥ 0.3 kg/m(2) increase of body mass index value per month (p=0.03; OR=1.61; 95% CI: 1.04-2.49) and low fat percentage; i. e., < 7% for players aged 11-16 and < 5% for players over 16 years (p=0.01; OR=1.81; 95% CI: 1.18-2.76). Individual monitoring of anthropometrics provides useful information to determine increased risk of injury occurrence in elite-standard youth soccer.