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Background: Running overuse injuries (ROIs) occur within a complex, partly injury-specific interplay between training loads and extrinsic and intrinsic risk factors. Biomechanical risk factors (BRFs) are related to the individual running style. While BRFs have been reviewed regarding general ROI risk, no systematic review has addressed BRFs for specific ROIs using a standardized methodology. Objective: To identify and evaluate the evidence for the most relevant BRFs for ROIs determined during running and to suggest future research directions. Design: Systematic review considering prospective and retrospective studies. (PROSPERO_ID: 236,832). Data Sources: PubMed. Connected Papers. The search was performed in February 2021. Eligibility Criteria: English language. Studies on participants whose primary sport is running addressing the risk for the seven most common ROIs and at least one kinematic, kinetic (including pressure measurements), or electromyographic BRF. A BRF needed to be identified in at least one prospective or two independent retrospective studies. BRFs needed to be determined during running. Results: Sixty-six articles fulfilled our eligibility criteria. Levels of evidence for specific ROIs ranged from conflicting to moderate evidence. Running populations and methods applied varied considerably between studies. While some BRFs appeared for several ROIs, most BRFs were specific for a particular ROI. Most BRFs derived from lower-extremity joint kinematics and kinetics were located in the frontal and transverse planes of motion. Further, plantar pressure, vertical ground reaction force loading rate and free moment-related parameters were identified as kinetic BRFs. Conclusion: This study offers a comprehensive overview of BRFs for the most common ROIs, which might serve as a starting point to develop ROI-specific risk profiles of individual runners. We identified limited evidence for most ROI-specific risk factors, highlighting the need for performing further high-quality studies in the future. However, consensus on data collection standards (including the quantification of workload and stress tolerance variables and the reporting of injuries) is warranted. [ABSTRACT FROM AUTHOR]

Background: It has become common practice to incorporate balance tasks into the training program for athletes who want to improve performance and prevent injuries, in rehabilitation programs, and in fall prevention programs for the elderly. However, it is still unclear whether incorporating balance tasks into a training program increases performance only in these specific tasks or if it affects balance in a more general way. Objectives: The objective of this systematic literature review and meta-analysis was to determine to what extent the training of balance tasks can improve performance in non-trained balance tasks. Data Sources: A systematic literature search was performed in the online databases EMBASE, PubMed, SPORTDiscus and Web of Science. Articles related to balance training and testing in healthy populations published between January 1985 and March 2015 were considered. Study Eligibility Criteria: A total of 3093 articles were systematically evaluated. Randomized controlled trials were included that (i) used only balance tasks during the training, (ii) used at least two balance tests before and after training, and (iii) tested performance in the trained balance tasks and at least one non-trained balance task. Six studies with a total of 102 subjects met these criteria and were included into the meta-analysis. Study Appraisal and Synthesis Methods: The quality of the studies was evaluated by means of the Physiotherapy Evidence Database (PEDro) scale. A random effect model was used to calculate the between-subject standardized mean differences (SMD) in order to quantify the effect of balance training on various kinds of balance measures relative to controls. The tested balance tasks in each study were classified into tasks that had been trained and tasks that had not been trained. For further analyses, the non-trained balance tasks were subdivided into tasks with similar or non-similar body position and similar or non-similar balance perturbation direction compared to the trained task. Results: The effect of balance training on the performance of the trained balance tasks reached an SMD of 0.79 [95 % confidence interval (CI) 0.48-1.10], indicating a high effect in favor for the trained task, with no notable heterogeneity ( I = 0 %). The SMD in non-trained categories reached values between −0.07 (95 % CI −0.53 to 0.38) and 0.18 (95 % CI −0.27 to 0.64), with non-notable to moderate heterogeneity ( I = 0-32 %), indicating no effect of the balance training on the respective non-trained balance tasks. Limitations: With six studies, the number of studies included in this meta-analysis is rather low. It remains unclear how the limited number of studies with considerable methodological diversity affects the outcome of the SMD calculations and thus the general outcome of the meta-analysis. Conclusion: In healthy populations, balance training can improve the performance in trained tasks, but may have only minor or no effects on non-trained tasks. Consequently, therapists and coaches should identify exactly those tasks that need improvement, and use these tasks in the training program and as a part of the test battery that evaluates the efficacy of the training program. Generic balance tasks-such as one-leg stance-may have little value as overall balance measures or when assessing the efficacy of specific training interventions. [ABSTRACT FROM AUTHOR]

Background: The importance of trunk muscle strength (TMS) for physical fitness and athletic performance has been demonstrated by studies reporting significant correlations between those capacities. However, evidence-based knowledge regarding the magnitude of correlations between TMS and proxies of physical fitness and athletic performance as well as potential effects of core strength training (CST) on TMS, physical fitness and athletic performance variables is currently lacking for trained individuals. Objective: The aims of this systematic review and meta-analysis were to quantify associations between variables of TMS, physical fitness and athletic performance and effects of CST on these measures in healthy trained individuals. Data Sources: PubMed, Web of Science, and SPORTDiscus were systematically screened from January 1984 to March 2015. Study Eligibility Criteria: Studies were included that investigated healthy trained individuals aged 16-44 years and tested at least one measure of TMS, muscle strength, muscle power, balance, and/or athletic performance. Study Appraisal and Synthesis Methods: Z-transformed Pearson's correlation coefficients between measures of TMS and physical performance were aggregated and back-transformed to r values. Further, to quantify the effects of CST, weighted standardized mean differences (SMDs) of TMS and physical performance were calculated using random effects models. The methodological quality of CST studies was assessed by the Physiotherapy Evidence Database (PEDro) scale. Results: Small-sized relationships of TMS with physical performance measures (−0.05 ≤ r ≤ 0.18) were found in 15 correlation studies. Sixteen intervention studies revealed large effects of CST on measures of TMS (SMD = 1.07) but small-to-medium-sized effects on proxies of physical performance (0 ≤ SMD ≤ 0.71) compared with no training or regular training only. The methodological quality of CST studies was low (median PEDro score = 4). Conclusions: Our findings indicate that TMS plays only a minor role for physical fitness and athletic performance in trained individuals. In fact, CST appears to be an effective means to increase TMS and was associated with only limited gains in physical fitness and athletic performance measures when compared with no or only regular training. [ABSTRACT FROM AUTHOR]