Background: Return to play (RTP) after total hip arthroplasty (THA) is increasingly expected by younger and more physically active patients. Current activity recommendations remain heterogeneous and are largely derived from expert opinion and indirect biomechanical modelling approaches, rather than direct in vivo biomechanical evidence. The aim of this article is to systematically map and synthesize the evidence from instrumented hip implant studies and to clarify how direct in vivo telemetry data can inform RTP counselling after THA. Methods: A scoping review was conducted according to a predefined Open Science Framework protocol and reported following PRISMA-ScR guidelines. MEDLINE (PubMed) and Scopus were searched from inception. Peer-reviewed clinical studies reporting direct in vivo biomechanical measurements obtained from instrumented hip implants were included. Conference proceedings, technical notes, reviews, and in vitro or computational-only studies were excluded. Data were extracted and synthesized descriptively according to activity domain, biomechanical variables, and implant technology. Results: Fifty studies met the inclusion criteria. Early investigations established feasibility and evolved from wired strain-gauge systems to fully implantable telemetric prostheses capable of measuring three-dimensional forces, moments, and friction-related parameters. Across cohorts, level walking consistently produced peak hip contact forces of approximately 2–3 times body weight, serving as a clinically meaningful reference loading envelope. Several recreational activities—including cycling, aquatic exercise, Nordic walking, and most gym-machine exercises—generally remained within or close to this range when performed with controlled technique. In contrast, certain rehabilitation tasks, forward-bent postures, lifting maneuvers, and perturbation events generated loads equal to or exceeding those observed during walking. Importantly, frictional moments and load direction showed substantial variability and may be more relevant to implant fixation than peak force magnitude alone. Conclusions: Instrumented hip implants provide objective biomechanical benchmarks that support principle-based and individualized RTP counselling, grounded in directly measured mechanical exposure rather than sport classification alone.

Introduction: Chronic non-specific low back pain (CNLBP) is associated with altered lumbopelvic mechanics and impaired hip mobility. This study examined whether changes in pain-provoking hip flexion are associated with changes in low back pain and assessed agreement between inertial measurement units (IMUs) and a markerless motion capture system. Methods: Thirty-six patients with CNLBP completed a longitudinal repeated-measures rehabilitation protocol consisting of approximately 13 physiotherapy sessions over a period of up to 6 weeks. Active hip flexion was assessed in the symptomatic limb (the limb provoking lumbar pain). Hip flexion was recorded during the same movement trial using IMUs and a markerless system. Pain and disability were assessed using the Visual Analogue Scale and Oswestry Disability Index. Results: Improvements in hip flexion were moderately associated with pain reduction (markerless: r = −0.52; IMU: r = −0.57), with negligible associations with disability. Markerless and IMU measurements showed a strong correlation (r = 0.87), while Bland–Altman analysis showed consistent underestimation by the markerless system (bias = −3.67°). Conclusions: Symptom-specific hip mobility is associated with pain reduction in CNLBP, highlighting the role of lumbopelvic biomechanics. IMUs demonstrated higher consistency, while markerless systems offered a more accessible alternative for clinically meaningful movement assessment.

(1) Background: A parsimonious test battery is deemed necessary to efficiently assess the functional performance of athletes avoiding redundant measurements. This study investigates the interrelationships between elements of an experimental field-based test battery during pre-season assessment (PA), with the purpose of enhancing comprehension of the underlying structure of the assessed variables and suggesting guidelines for the tests incorporated in a PA. (2) Methods: Sixty-two professional football athletes performed a PA, including isometric muscle strength, triple hop and core stability tests, the LESS, and evaluation of landing performance through kinetic and electromyographic data. (3) Results: For the dominant lower limb, the factor analysis resulted in six factors, explaining 79.04% of the variance including core stability, ground reaction forces, dynamic balance, hamstrings strength, quadriceps–hamstring EMG ratio, and quadriceps performance. For the non-dominant lower limb, factor analysis resulted in five factors, explaining 76.60% of the variance including core stability, dynamic balance, ground reaction force, quadriceps–hamstring EMG ratio, and quadriceps–abductors strength. The LESS was loaded with various factors. (4) Conclusions: Given the need for efficient field-based assessments that can be repeated throughout the season without sacrificing data quality, we suggest incorporating the LESS, the prone bridge test, and force-plate-based landing performance evaluation as key elements of the PA.

Background and Objectives: Recent research has highlighted the importance of examining risk factors and their complex interrelationships in the development of lower limb injuries. This study aimed to investigate the direct, indirect, and mediating effects of endogenous neuromuscular and psychological risk factors on the incidence of non-contact lower limb injuries in football players. Materials and Methods: A sample of ninety-seven male football players underwent a structured preseason, on-field assessment. Demographic characteristics, injury history, and athlete burnout were collected through standardized questionnaires. Preseason evaluations included assessments of lower limb flexibility; isometric strength assessment of hamstring, hip abductors, and quadriceps using a handheld dynamometer; hamstring and core endurance; and the single-leg triple hop for distance test. All non-contact lower limb injuries were prospectively recorded throughout the competitive season. Partial Least Squares Structural Equation Modeling (PLS-SEM) method was applied to examine both direct and indirect associations between preseason risk factors and injury incidence. Results: Lower limb strength asymmetries (path coefficient (PC) 0.293, p = 0.004) and previous injuries (PC 0.233, p = 0.015) exhibited the strongest direct effects on the occurrence of new non-contact lower limb injuries. In addition, age acted as a moderating factor, amplifying the effect of lower limb strength asymmetries on injury risk. Moreover, previous injuries demonstrated both direct and indirect effects on neuromuscular characteristics and perceived burnout. Core and hamstring endurance tended to influence new injuries indirectly through strength asymmetries and were significantly affected by hamstring strength (PC 0.248, p = 0.015) and prior injuries (PC -0.207, p = 0.029). Conclusions: Injury prevention strategies should prioritize the improvement of core and hamstring endurance and the reduction in lower limb Strength Asymmetries, particularly among older football players. Furthermore, individualized preventive interventions for athletes with a previous history of injury are strongly recommended.

Objectives: Shoulder injury prevalence appears to be the highest among all injuries in CrossFit (CF) athletes. Nevertheless, there is no evidence deriving from prospective studies to explain this phenomenon. The purpose of this study was to document shoulder injury incidence in CF participants over a 12-month period and prospectively investigate the risk factors associated with their demographic, epidemiological, and functional characteristics. Methods: The sample comprised 109 CF athletes in various levels. Participants’ data were collected during the baseline assessment, using a specially designed questionnaire, as well as active range of motion, muscle strength, muscle endurance, and sport-specific tests. Non-parametric statistical tests and inferential statistics were employed, and in addition, linear and regression models were created. Logistic regression models incorporating the study’s continuous predictors to classify injury occurrence in CF athletes were developed and evaluated using the Area Under the ROC Curve (AUC) as the performance metric. Results: A shoulder injury incidence rate of 0.79 per 1000 training hours was recorded. Olympic weightlifting (45%) and gymnastics (35%) exercises were associated with shoulder injury occurrence. The most frequent injury concerned rotator cuff tendons (45%), including lesions and tendinopathies, exhibiting various severity levels. None of the examined variables individually showed a statistically significant correlation with shoulder injuries. Conclusions: This is the first study that has investigated prospectively shoulder injuries in CrossFit, creating a realistic profile of these athletes. Despite the broad spectrum of collected data, the traditional statistical approach failed to identify shoulder injury predictors. This indicates the necessity to explore this topic using more sophisticated techniques, such as advanced machine learning approaches.

This paper propose a practical field-based screening protocol for evaluating the risk of hamstring injury. This is done by discerning the most important factors that better explain the underlying structure among various measurements. Following a cross-sectional study design, ninety-nine professional and semi-professional football players were assessed at the team’s facilities during the preseason period. The collected data included aspects of demographic characteristics; previous injuries; athlete sense of burnout (Athlete Burnout Questionnaire (ABQ)); hamstring (HS) flexibility (passive single leg raise test); isometric hamstring strength (make and brake test); isometric quadriceps strength; single-leg triple hop for distance; endurance of the core muscles (prone bridge, side bridge and Biering–Sørensen tests); and hamstring strength endurance (single leg hamstring bridge test). Subsequently, Exploratory Factor Analysis was performed. Following a summarized dimension reduction process, the twenty-three assessment variables were grouped into a parsimonious model of six main risk factors. Specifically, the resulting model explains 55.7% of the total variance, comprising HS and core endurance (20.2% of the variance), HS strength (12.8%), previous injuries (8.9%), ABQ (5.8%), lower limb strength (4.1%), and strength limb symmetry (3.8%). The proposed model provides a practical protocol, facilitating sports scientists in evaluating the risk for HI in the highly complex reality of field-based situations.

This study investigates the impact of postretirement organizational work on the well-being and overall quality of life of the elderly population in Cyprus. Specifically, it evaluates the multifaceted effects of continued employment after retirement, based on data collected through a survey administered to a representative sample of elderly Cypriots. The research findings, informed by prominent instruments in the field, demonstrate significant enhancements in autonomy, self-actualization, and both physical and psychological well-being for the elderly as a result of continuing to work beyond retirement age. Through inferential statistical analysis, the study identifies several key factors contributing to significant improvements in people’s lives. Particularly, the findings reveal a positive correlation between sustained employment and several aspects of quality of life, challenging conventional views on retirement. These insights hold particular relevance for the Cypriot context and suggest broader implications for policymaking that encourage postretirement employment as a means to enhance well-being in countries with aging populations. Overall, this paper contributes to the discourse on organizational work, aging, and quality of life by offering evidence-based policy recommendations for enhancing human self-actualization and well-being through sustainable professional engagement.

It is essential for physical sports therapists to use reliable field-based tests to identify potential injury risk factors in athletes. The purpose of this study was to compare the inter- and intra-rater reliability of experienced and novice raters during use of the Landing Error Scoring System (LESS) in a field-based examination of professional football athletes. Thirty-seven male football athletes underwent pre-season LESS assessment. Two raters independently evaluated the recorded landing techniques at two separate intervals, two months apart, following the LESS standard protocol. Inter-and intra-rater values were calculated for the LESS total scores and individual scoring items. The overall LESS scores had excellent intra-rater reliability values for both the experienced (interclass correlation coefficient (ICC) = 0.95, 95% CI, 0.89–0.97; p < 0.001) and novice rater (ICC = 0.95, 95% CI, 0.90–0.97; p < 0.001), and very good to excellent inter-rater values for the first (ICC = 0.90, 95% CI, 0.77–0.95; p < 0.001) and second (ICC = 0.86, 95% CI, 0.71–0.93; p < 0.001) evaluation. Most of the individual scoring items ranged from moderate to perfect agreement. In conclusion, sports physical therapists, regardless of experience, can reliably use the LESS’s total score, through video analysis of the regime. Individual scoring items can inform clinicians about impairments in the landing mechanism but data should be interpreted cautiously.

Background/Objectives: Given the complex nature of Anterior Cruciate Ligament (ACL) injury, it is important to analyze its etiology with suitable approaches in order to formulate intervention strategies for effective prevention. The present study employs system thinking techniques to develop a Causal Loop Diagram (CLD) Model for investigating the risk factors for ACL Injury (CLD-ACLI), through a Group Model Building approach. Methods: A two-stage procedure was applied involving a comprehensive literature review followed by several systems thinking group-modeling co-creation workshops with stakeholders. Results: Based on input from experts and stakeholders, combined with the latest scientific findings, the derived CLD-ACLI model revealed a series of interesting complex nonlinear interrelationships causal loops between the likelihood of ACL injury and the number of risk factors. Particularly, the interaction among institutional, psychological, neurocognitive, neuromuscular, malalignment factors, and trauma history seem to affect neuromuscular control, which subsequently may alter the biomechanics of landing, predisposing the ACL to injury. Further, according to the proposed CLD-ACLI model, the risk for injury may increase further if specific environmental and anatomical factors affect the shear forces imposed on the ACL. Conclusions: The proposed CLD-ACLI model constitutes a rigorous useful conceptual presentation agreed upon among experts on the dynamic interactions among potential intrinsic and extrinsic risk factors for ACL injury. The presented causal loop model constitutes a vital step for developing a validated quantitative system dynamics simulation model for evaluating ACL injury-prevention strategies prior to implementation.

Background and objectives This study aims to introduce an innovative functional assessment tool designed for CrossFit athletes, to identify a high risk of injury at the shoulder joint. Additionally, the study seeks to examine both inter -rater reliability, which was tested in 40 CrossFit participants, and test -retest reliability, which was assessed in twenty subjects. Methodology CrossFit Functional Assessment Battery for the Shoulder Joint (CrossFit FABS) is a newly created instrument presented for the first time. The evaluation of the performance of its six items aimed to reveal deficits that could contribute to incidents of shoulder injuries. For this purpose, 40 healthy CrossFit participants were concurrently but independently examined by two raters, and twenty healthy adults active in sports were assessed by the main investigator at two different time points. Cohen's kappa coefficient was used to analyze categorical data with an ordinal structure. Results Inter -rater reliability ranged from 0.824 to 1 (P = 0.000) and test -retest reliability was 0.661 to 0.906 (P < 0.001) for each test of CrossFit FABS. A strong to almost perfect correlation was demonstrated for all the variables between the two examiners. Moderate to almost perfect correlation was shown through test -retest procedures. Conclusions The proposed test battery was established as a reliable tool for evaluating performance routines that represent high injury -risk elements for the shoulder joint in CrossFit athletes.

(1) Background: There is a need for a parsimonious test battery to efficiently assess the functional performance of athletes without redundant measurements. This study investigates the interrelationships between elements of an experimental field-based test battery during pre-season assessment (PA), with the purpose of enhancing comprehension of the underlying structure of the assessed variables and suggesting guidelines for the tests incorporated in a PA; (2) Methods: Sixty-two professional athletes performed a PA included strength, hop and core stability tests and evaluation of landing performance through kinetic and electromyographic data; (3) Results: For the dominant lower limb, the factor analysis resulted in 6 factors, explaining 79,04 % of the variance including core stability, Ground Reaction Forces, Dynamic balance, Hamstrings Strength, Quadriceps-Hamstring EMG ratio and Quadriceps performance. For the non-dominant lower limb, factor analysis resulted in 5 factors, explaining 76,60 % of the variance including Core stability, Dynamic balance, Ground Reaction Force, Quadriceps-Hamstring EMG ratio and Quadriceps - Abductors Strength. LESS was loaded with various factors. (4) Conclusions: Given the need for efficient field-based assessments that can be repeated throughout the season without sacrificing data quality, we suggest incorporating LESS, the prone bridge test, and force plate-based landing performance evaluation as key elements of the PA.

There is a gap in the literature regarding the complex interrelationships among hamstring injury (HI) risk factors. System dynamics (SD) modeling is considered an appropriate approach for understanding the complex etiology of HI for effective injury prevention. This study adopted the SD method and developed a causal loop model (CLD) to elucidate the intricate relationships among HI risk factors. This is performed by combining literature evidence and insights from expert stakeholders through a group model building (GMB) approach. The GMB methodology facilitated the identification of sixty-five critical factors influencing the HI risk, revealing the dynamic interplay between factors. Stakeholder engagement underscored the importance of previous injury characteristics (level of influence of previous injury, severity of previous injury, quality and size of scar tissue) and the quality of rehabilitation. HI-CLD revealed that many factors had indirect effects on HI risk. The HI-causal loop model establishes a foundation for a future stock and flow quantitative SD model aiming to advance HI prevention strategies through an interdisciplinary collaborative effort. These findings underscore the complexity of HI prevention, necessitating a holistic approach that integrates the views of diverse professional expertise. Appropriate inter-professional collaboration and continuous athlete screening are important for effective injury prevention strategies.

(1) Background: Osteoarthritis (OA) is a serious chronic disease mostly affecting the knee joint. Despite the many efforts for developing strategies to predict and control Knee Osteoarthritis (KOA), the disease is on the rise. This paper describes the process for the creation of a simulation model, the Dynamic Knee Osteoarthritis Simulation (DYNAMIKOS) model, that captures the complex interrelationships of the risk factors for the development of KOA; (2) Methods: The DYNAMIKOS model will be based on the System Dynamics approach. The first step will be to develop a Causal Loop Diagram (CLD) model for the risk factors involved incorporating a series of Group Modeling Building (GMB) workshops with experts and stakeholders. Using data from a representative sample of KOA patients, the statistical approaches Exploratory Factor Analysis, Confirmatory Factor Analysis, and Structural Equation Modeling (SEM) will be carried out. (3) Results: This study will develop a simulation System Dynamics model for the risk factors of KOA based on the results of CLD and SEM; (4) Conclusions: The proposed DYNAMIKOS model could be used for effectively analyzing the complex interrelationships among the multiple factors that constitute the spread of KOA. In this way, plausible prevention strategies could be implemented for effectively managing and leading the potential eradication of KOA.

Objectives:The objective of this pilot study was to investigate the feasibility of a three month 'Motor control Home ergonomics Elderlies' Prevention of falls' (McHeELP) programme on muscle mass, muscle strength, functionality, balance and fear of falling among older adults with sarcopenia. Methods:A feasibility study of the McHeELP programme was performed in patients with sarcopenia. Primary outcome measures included number of participants; number of participants that showed engagement with the programme; adherence rates; data loss in questionnaires and secondary outcome measures; any adverse events, related or not to the intervention programme. All participants received a home-based motor control exercise programme combined with an ergonomic home modification for 12 weeks. Secondary outcome measures included Hand Grip Strength, Bioimpendance Analysis, Muscle Mass, Functionality and Fear of Falling. Results:Twelve participants, (74.9±5 years), completed the pilot study. Significant differences were recorded before and after the programme on participants' functionality (p < 0.001), balance (p < 0.05) and fear of falling (p < 0.001). Conclusions:The present study revealed that the McHeELP programme is fesasible and that it is possible to implement the programme in clinical practice. The McHeELP programme positively affects functionality, balance and fear of falling. Thus, it seems feasible to conduct a full-scale randomised controlled trial.

Introduction and hypothesis Despite exercise being the standard approach to diastasis recti abdominis (DRA) rehabilitation, there is no consensus on the most effective exercise routine and adjunct modalities for reducing DRA and improving functional parameters. The present study is aimed at investigating evidence for DRA rehabilitation in postpartum women, as well as knowledge gaps and areas for future research. Methods For this scoping review a systematic search was conducted in MEDLINE, AMED, CINAHL, Embase, ScienceDirect, Scopus, and PEDro up to November 2022. Selection criteria included studies investigating exercise therapy interventions both with and without adjunct modalities for postpartum DRA. Sample characteristics, diagnostic criteria, program design, and outcome measures were recorded. Critical appraisal of clinical trials was performed using PEDro classification. Results Twenty-eight studies were included: 14 clinical trials, 3 case series, and 11 observational studies. DRA exercises that focused on deep and superficial muscles, pelvic floor muscles, respiratory maneuvers, functional exercises, or alternative interventions (yoga, suspension training, hypopressive exercise) and adjunct modalities showed promising results in reducing the inter-recti distance and related dysfunction. However, there was great variability in diagnostic criteria and methods, DRA severity, time post-birth, and exercise program design. Conclusions Reviewed studies provide valuable insights into exercise therapy, but it is important to recognize their limitations, as variability in diagnostic criteria, sample characteristics, and exercise program design hinder the generalizability of the findings. Further high-quality research is needed to strengthen the evidence in this area and provide reliable recommendations for clinical practice.

Acute lower extremity (LE) injuries constitute a significant problem for team sports, with major long-and short-term consequences for athletes and their teams. For this reason, a wide range of research has been focused on strategies of prediction and prevention for LE injury. Knowledge of the key risk factors and their interrelationships in the system of injury etiology is the first and essential step towards formulating appropriate prevention procedures. This paper presents recent evidence regarding the factors related to the risk of acute noncontact LE injuries. The literature review identifies many intrinsic and extrinsic factors implicated in the etiology of LE injury, of which previous injury, gender and workload appear to have a stronger association with the occurrence of injuries. The evidence for a group of well-researched modifiable factors, such as strength variables, balance, fatigue and flexibility, is conflict-ing. Despite the evidence for each factor independently, the etiology of LE injury appears to be complex and dynamic, and research in sports injuries should, therefore, incorporate new methodologies capable of capturing this dynamic complexity in order to better understand and prevent sports injuries.

Objective Identifying risk factors for Achilles Tendon Rupture (ATR) is one of the first necessary steps for its prevention. This systematic review aimed to update the systematic review published in 2014 in ATR etiology. Methodology A systematic review was carried out using PubMed, EBSCO, and ScienceDirect databases. All types of research studies (Randomized Control Trials - RCTs, Cohort studies, Case-control studies and Cross-sectional studies) that considered ATR, were eligible. The inclusion criteria for eligibility of the studies were to be written in the English language, and to include populations of men and/or women, both athletes, and non-athletes, healthy individuals, and patients. Two independent reviewers used the assessment instrument Newcastle-Ottawa Scale independently, to evaluate the quality of each selected study. Further, two reviewers worked independently to extract the study characteristics, and the GRADE methodology was used to assess the level of certainty of each risk factor. Results From 9526 studies initially identified, 19 studies were eligible for further analysis to identify risk factors for ATR. Seventeen studies were considered good quality, and two studies fair quality. Low to very low certainty of evidence was found for the following medications: steroids, quinolones, and oral bisphosphonate, as well as for other factors such as chronic tendon inflammation and Achilles' tendinopathy, spring season, diabetes, previous musculoskeletal injury, regular participation in athletic activity, hyperparathyroidism, renal failure, and genetic factors. Conclusions The risk factors found prove that ATR is a multifactorial injury. Appropriate methodologies and well-designed studies are needed to determine the factors and their significance in ATR risk. Finally, the role of biomechanical and psychological aspects in the ATR etiology may be of interest in future studies, as we could not extract relative data in our review.

Acute noncontact Lower Extremity (LE) injuries constitute a significant problem in team sports. Despite extensive research, current knowledge on the risk factors of LE injuries is limited to static simplistic models of instantaneous cause and effect relationships ignoring the time dimension and the embedded complexity of LE injuries. Even though complex systems approaches have been used in various cases to improve policy and intervention effectiveness, there is limited research on predicting and managing LE injuries. This creates an opportunity to fill the gap in the current literature by applying the System Dynamics (SD) methodology to model LE injuries. The proposed approach allows for synthesizing risk factors and examining their interaction. This paper makes the first step towards such an approach by developing a causal loop model revealing the etiology of LE injuries. A causal loop model for LE injuries is developed via an extensive literature review and brainstorming with experts. In contrast to the traditional static approaches, the proposed model reveals some of the complexity and nonlinear relationships of the various sports injury risk factors. The derived causal loop model may then be used to quantify these interactions and develop a simulation model. This will be achieved by operationalizing and incorporating the main risk factors that impact LE injuries in an integrated sports injury prediction model. In this way, plausible strategies for preventing LE injuries can be tested prior implementation and thereby achieve optimization of intervention programs.