Alasdair Dempsey

Context
The double-leg Landing Error Scoring System (LESS) identifies noncontact ACL injury risk. However, its intersession reliability has been examined in only one study. As such injuries often occur during single-leg landings, research on the single-leg LESS (SLESS) in field settings remains lacking. Therefore, our study investigated the intersession, intrarater, and interrater reliability of single- and double-leg jump-landing tasks using SLESS and LESS.

Methods
Thirty-five team-sports players (age: 26.4 [6.7] years, n = 28 males and 7 females) performed 3 jump-landing variations (single-leg dominant and nondominant and double leg) across 3 sessions. We conducted sessions 1 and 2 on the same day, with session 3 one week later. Three assessors rated video footage to determine SLESS and LESS total scores. Reliability was assessed using the intraclass correlation coefficient (ICC), standard error of measurement, and coefficient of variation (CV) with 95% CIs.

Results
Intersession reliability for the SLESS and LESS scores showed good to excellent ICCs (dominant leg: .89, nondominant leg: .91, double leg: .79) with moderate CVs (dominant leg: 6.5%, nondominant leg: 6.6%, double leg: 7.9%). Intrarater reliability for the SLESS and LESS scores also demonstrated good to excellent ICCs (dominant leg: .94, nondominant leg: 0.92, double leg: .88) with moderate CVs (dominant leg: 5.0%, nondominant leg: 6.0%, double leg: 5.6%). Interrater reliability for the SLESS and LESS scores exhibited good ICCs (dominant leg: .82, nondominant leg: .83, double leg: .79) but poor CVs (dominant leg: 10.5%, nondominant leg: 11.5%, double leg: 11.5%). Single-leg LESS and LESS scores exhibited small standard error of measurement values between 1.05 and 1.11 for all reliability measures.

Conclusions
The SLESS and LESS are reliable field-based tools for assessing jump-landing tasks among team-sports players, facilitating confidence in sports and exercise science research.

In forensic investigations of physical assaults involving weapon use, the analysis of damage to soft tissues, bones, and textiles can yield critical insights into the weapon and the dynamics of the incident. This intelligence is obtained by examining the damage, as well as potentially simulating and reconstructing the incident. Existing simulation models range from human-based trials to mechanical apparatus, though all are inadequate in accurately replicating incidents due to factors such as human variability, lack of controlled force application, and inconsistent reproducibility. This study evaluates the potential of robotic arms to address existing simulation limitations, highlighting their capabilities, such as human-like motions, programmability, precision, and repeatability, that may assist in standardising weapon impact simulations and damage reconstruction.

The human stabbing action is a dynamic interaction between the assailant and a victim, resulting in sharp force damage. The morphology of such damage is influenced by multiple parameters before, during, and after the stabbing incident. In forensic investigations , examining wounds and textile damage provides critical information about the implement used, the method of stabbing, and the associated physical interaction between the assailant and the victim. This information aids in reconstructing events and determining whether injuries are homicidal, accidental, or self-inflicted. The assessment of tissue and textile damage involves qualitative analysis followed by hypothesis testing of simulated stabbing incidents and damage reconstruction. Currently, these reconstructions are manually performed by forensic practitioners, but variability exists in stabbing actions both between and within individuals, leading to limitations in accuracy, repeatability, and reliability. The present review represents the most current comprehensive overview of the factors affecting sharp force damage. It discusses the process of damage analysis with an emphasis on textile damage and discusses both manual and mechanical simulation methods used in research and forensic casework. It highlights the capabilities and limitations of these approaches, offering directions for future investigations and their forensic applications. Tables detailing the design and results of manual and mechanical experiments conducted since the 1920s are provided to assist operators. Finally, advanced methods , such as robotic arms that mimic human motions, are discussed as potential solutions to some of the current limitations, with the aim of enabling standardization in sharp force damage analysis and reconstruction. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Introduction
Implementing blood flow restriction (BFR) during walking is gaining momentum, with a benefit of this approach being reduced absolute external training intensity, still resulting in chronic adaptations to aerobic fitness (1) and muscular strength (2). BFR-walking leads to acute systemic and local physiological adjustments (3, 4). Systemically, hemodynamic stability is reduced, decreasing venous return, cardiac preload, and stroke volume (5). To compensate, heart rate increases to maintain cardiac output (6) while minute ventilation simultaneously increases as the demand for oxygen rises (2). Locally, reductions in oxygen delivery and removal of metabolic waste create a localized hypoxic environment, lowering muscular pH (3). Consequently, BFR-walking is considered a suitable exercise for load-compromised individuals such as older adults, injured athletes, and patients with chronic musculoskeletal disorders (7).

Literature outside of BFR research indicates acidic environments impair muscle contractility and/or develop a sub-optimal shortening velocity, reducing the power output of muscular contractions (8). Prolonged exposure to the localized hypoxic environment could disturb the contractility of leg muscles during walking. Of particular concern is the reduced contractility of the plantar-flexors, the predominant power generators walking (9). Altered submaximal contractibility of the plantar-flexors could cause neuro-mechanical compensatory strategies and redistribute a portion of the mechanical force created at the ankle to the hip and knee to maintain walking speed (10). To accommodate the redistribution of power, changes in spatio-temporal and/or kinematic characteristics would occur (10). Therefore, we intend to discuss how applying BFR may modify critical characteristics of one's natural gait cycle (Figure 1).

Context: As blood flow restriction gains popularity across different populations (eg, young and older adults) and settings (eg, clinical and sports rehabilitation), the accuracy of blood flow restricted percentage becomes crucial. We aimed to compare manually measured arterial occlusion pressure (AOP) among young adults to understand whether lower limb composition affects the pressure required to achieve AOP. The results will shed light on the adequacy of published calculations used to estimate AOP in practical and research settings.

Design: An observational cross-sectional study design was implemented to examine the relationship between lower limb composition, lower limb circumference, and measured AOP.

Methods: Twenty-two participants (12 males, 26 [4] y, 1.74 [0.07] m, 73.2 [12.5] kg) underwent a whole-body Dual-energy X-ray Absorptiometry scan before AOP (in millimeters of mercury) and lower limb circumference (in centimeters) were determined. In a supine position, a 10-cm wide cuff was manually inflated on the dominant leg to the point where a pulse could no longer be detected by a Doppler ultrasound of the posterior tibial artery to determine AOP. Lower limb composition (fat, muscle, and bone mass [in grams]) was obtained from the Dual-energy X-ray Absorptiometry scan.

Results: Lower limb muscle mass had a moderate negative relationship with AOP (r2 = .433, β = -0.004) and a moderate positive relationship with lower limb circumference (r2 = .497, β = 0.001). Lower limb circumference had the weakest relationship with AOP (r2 = .316, β = 0.050) of all measures.

Conclusions: The reported relationships between lower limb muscle mass, lower limb circumference, and AOP suggest that as muscle mass increases, lower limb circumference also increases, yet AOP decreases. This implies that limb circumference should not be used as the primary measure for calculating AOP within the sampled population. We recommend individually measuring AOP when implementing blood flow restriction in all exercise modalities.

This study examined the impact of continuous blood flow restriction (BFR) during repeated-sprint exercise (RSE) on acute performance, peripheral, systemic physiological, and perceptual responses. In a randomized crossover design, 26 adult male semi-professional and amateur team-sport players completed two RSE sessions (3 sets of 5 x 5-s sprints with 25 s of passive recovery and 3 min of rest) with continuous BFR (45% arterial occlusion; excluding during between-set rest periods) or without (non-BFR). Mean and peak power output were significantly lower (p < 0.001) during BFR compared to non-BFR (dz = 0.85 and 0.77, respectively). Minimum tissue saturation index during the sprints and rest periods was significantly reduced (p < 0.001) for BFR (dz = 1.26 and 1.21, respectively). Electromyography root mean square was significantly decreased (p < 0.01) for biceps femoris and lateral gastrocnemius muscles during BFR (dz = 0.35 and 0.79, respectively), but remained unchanged for the vastus lateralis muscle in both conditions. Oxygen consumption and minute ventilation were significantly reduced (both p < 0.01) for BFR (dz = 1.46 and 0.43, respectively). Perceived limb discomfort was significantly higher (p < 0.001) for BFR (dz = 0.78). No differences (p > 0.05) in blood lactate concentration or rating of perceived exertion were observed between conditions. Blood flow-restricted RSE reduced performance and likely increased the physiological and perceptual stimulus for the periphery with greater reliance on anaerobic glycolysis, despite comparable or decreased systemic demands.

Introduction: Noncontact anterior cruciate ligament (ACL) injuries during sports have increased in the last few decades. Effective injury screening tools are crucial to identifying injury risk and allowing for intervention. A systematic review of the current literature will allow exercise science professionals and researchers to identify reliable, ecologically valid, and predictive methods utilised in the ACL injury screening process. This systematic review aims to identify, critically evaluate and summarise noncontact ACL injury screening methods' reliability, validity, and predictability.

Methods:
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for this review. We systematically searched for articles in English in eight electronic databases (PubMed, Scopus, Web of Science, SciELO Citation Index, Cochrane Library, Ovid MEDLINE(R), CINAHL Complete (EBSCOhost) and SPORTDiscus). A search was conducted through databases from their creation until the 19th of January, 2022. Inclusion criteria were: peer-reviewed full-text articles reporting ACL injury screening methods' reliability, validity, and predictability, articles that reported the analysis of primary ACL injury and considered the biomechanical evaluation of kinematic and kinetic variables of the hip, knee, and ankle during a specific sporting task in both frontal and sagittal planes and the study done on humans. We used the Newcastle-Ottawa Quality Assessment Scale for Cohort studies and the Cochrane Group on Screening and Diagnostic Test Methodology (Cochrane methods) quality assessment tool was conducted to identify study bias in the included reliability and validity studies and the included prospective studies, respectively. The review is registered at the International Prospective Register of Systematic Reviews (PROSPERO, CRD42022331391).

Results:
The search yielded 14,375 studies, with 75 studies eligible for inclusion. We identified several screening methods for noncontact ACL injury. Screening methods included; three-dimensional (3D) motion analysis, two-dimensional (2D) video motion analysis, the Landing Error Scoring System (LESS), the Functional Movement Screen (FMS), and Real-time Observational Screening. We identified specific ACL injury screening tasks, including; drop jumps with double-leg landing, side-cutting, and single-leg squats. In the included studies, 16 studies reported the ability to predict injury risk, 59 studies reported the reliability of the screening method, and 13 studies reported the validity of the screening method against the gold standard 3D motion analysis system. The 3D motion analysis demonstrated good to excellent intra-rater reliability, ranging from ICC= 0.760-0.980, and moderate to excellent inter-session reliability, ranging from ICC= 0.600-0.916. The assessment of inter-rater reliability was not reported in any identified study. The 2D video motion analysis showed moderate to excellent intra-rater reliability, ranging from ICC= 0.672-1.000, and good to excellent inter-session reliability, ranging from ICC= 0.720-0.960. Inter-rater reliability varied, ranging from ICC= 0.140-1.000. The LESS provided good to excellent intra-rater reliability, ranging from ICC= 0.680-0.990, and good to excellent inter-rater reliability, ranging from ICC= 0.710-0.950. Inter-session reliability was not assessed for the LESS in any included study. The FMS exhibited poor to excellent intra-rater reliability, ranging from ICC= 0.372-0.960, good to excellent inter-rater reliability, ranging from ICC= 0.760-0.980, and moderate to excellent inter-session reliability, ranging from ICC= 0.600-0.950. The Real-time Observational Screening showed moderate to excellent intra-rater and inter-rater reliability, ranging from K= 0.550-0.900 and K= 0.520-0.920, respectively.

Discussion:
The systematic review identified several methods and specific tasks for noncontact ACL injury screening. The identified studies reported on the screening methods' predictability, reliability, and validity, with 3D motion analysis, 2D video motion analysis, LESS, FMS, and Real-time Observational Screening being the most commonly used methods. In general, the results showed good to excellent intra-rater and inter-rater reliability and moderate to high validity for the different screening methods, suggesting that these methods can be used to identify individuals at risk of noncontact ACL injury.

Impact/Application to the field:
Findings from this research may be helpful to inform sports and exercise science professionals to identify reliable, ecologically valid, and predictive methods utilised in the noncontact ACL injury screening process to prevent future injuries in athletes.

This study investigated the impact of blood flow restriction (BFR) during treadmill walking on gait kinematics. Twenty-one participants completed one familiarisation and four experimental sessions, including two walking speeds (moderate [5.0 ± 0.3km·h−1] and fast [6.4 ± 0.4km·h−1]) and two occlusion conditions (BFR [60% of arterial occlusion pressure] and unrestricted). For each exercise intensity, the BFR session was performed first. Participants were instructed to walk as long as possible, with sessions capped at 20 min. Unrestricted sessions were time-matched, and the order of exercise intensity was randomised. Kinematics were collected over 10s every minute using retro-reflective markers affixed to specific body landmarks. Ratings of perceived exertion and discomfort were collected every two minutes. Blood samples were collected from the fingertip pre-exercise and the finger and toe post-exercise, and were analysed for lactate, electrolytes, and markers of cell-membrane damage. During the BFR sessions the cuffs remained inflated while the blood samples were collected. Fast-walk BFR sessions exhibited higher anterior trunk flexion (p = 0.001) and knee flexion during stance (p = 0.001) compared to all other sessions. Step width was increased during BFR sessions (p = 0.001), but no difference in step length (p = 0.300) or cadence (p = 0.922) were observed. The time required to elicit change in anterior trunk flexion and plantar-flexion angle at toe-off was shorter during BFR sessions (p = 0.024). The BFR sessions elicited the highest ratings of perceived exertion and discomfort, as well as blood lactate concentration (p ≤ 0.001). Application of BFR during moderate and fast treadmill walking modifies gait kinematics and exacerbates exercise-related sensations as well as blood lactate concentration.

Highlights
• Applying blood flow restriction changes walking kinematics, causing an overall increase in anterior trunk flexion and knee flexion during stance while simultaneously reducing plantar-flexion angle at toe-off and ankle joint velocity.

• Applying blood flow restriction exacerbate exercise-related sensations of exertion and discomfort.

• Sample site does not influence the level of post-exercise blood lactate or markers of cell-membrane potential and damage.

Introduction:
In recent decades, there has been an increase in the incidence of noncontact anterior cruciate ligament (ACL) injuries during sports, leading to high costs for athletes, sports teams, and the healthcare system. These injuries often occur during single-leg drop jump landing. There is a lack of studies available on a screening tool to assess multiple planes of motion during a single-leg drop jump landing in the field-based setting. One study has investigated the inter-session reliability of the Landing Error Scoring System (LESS) during double-leg drop jump landing tasks. However, no study has assessed the inter-session reliability using the Single-leg Landing Error Scoring system (SLESS) during single-leg drop jump landing tasks. This study investigated the inter-session reliability of single-leg drop jump landing tasks (dominant and non-dominant leg) using the SLESS and compared them to the double-leg drop jump landing tasks (cognitive loading drill with double-leg and double-leg) using the LESS. The study further examined the intra-rater and inter-rater reliability of single-leg drop jump landing tasks using the SLESS and compared it to the LESS across three sports and exercise science professionals.

Methods:
The study involved twenty participants aged 18- 40 years who were team sports players. Participants performed four variations of drop jump landing tasks during three testing sessions based on standard methodology. Tasks were dominant leg, non-dominant leg, double-leg, and cognitive loading drill with double-leg. Sessions 1 and 2 were conducted on the same day, and Session 3 was conducted a week later. Participants followed an individualised testing order in Session 1, and a 1-minute rest period was provided between landing tasks. Video cameras captured frontal and sagittal views of all landing tasks. Three sports and exercise science professionals (two exercise scientists and one physiotherapist) scored the participant's recorded trials using the standard SLESS and the LESS protocols. One scorer assessed both intra-session and inter-session reliability, while three scorers assessed inter-rater reliability. The reliability of single-leg and double-leg drop jump landing tasks was determined using intraclass correlation coefficient (ICC) with 95% confidence interval (CI) values. The ICC used a two-way mixed effects absolute agreement mean of measurements, two-way mixed effects absolute agreement mean of k raters, and two-way random effects absolute agreement, multiple raters/measurements ICC (2,k) (k= number of raters/measurements).

Results:
The study observed good to excellent inter-session reliability for single-leg and double-leg drop jump landing tasks using the SLESS and the LESS (SD: ICC = 0.916 [95% CI; 0.820-0.965], SN: ICC = 0.907 [95% CI; 0.792-0.962], DL: ICC= 0.754 [95% CI; 0.455-0.898], DC: ICC= 0.886 [95% CI; 0.752-0.952]). Good to excellent intra-rater reliability was also observed for single-leg and double-leg drop jump landing tasks using the SLESS and the LESS (SD: ICC= 0.949 [95% CI; 0.868-0.980], SN: ICC= 0.888 [95% CI; 0.566-0.963], DL: ICC= 0.853 [95% CI; 0.629-0.942], DC: ICC= 0.870 [95% CI; 0.678-0.948]). In addition, moderate to good inter-rater reliability was observed for single-leg, and double-leg drop jump landing tasks using the SLESS and the LESS (SD: ICC= 0.800 [95% CI; 0.358-0.929], SN: ICC= 0.882 [95% CI; 0.712-0.953], DL: ICC= 0.861 [95% CI; 0.706-0.942], DC: ICC= 0.730 [95% CI; 0.278-0.897]).

Discussion:
This study provides evidence of the reliability of the SLESS and the LESS in assessing drop jump landing tasks performed by team sports players. These results suggest that both the SLESS and the LESS can be used confidently to assess drop jump landing tasks in sports and exercise science research.

Impact/Application to the field:
These tools may identify athletes at higher risk of noncontact ACL injury and direct training programs to prevent future injuries in athletes in the field. While reliable, the SLESS still need to have both validity and the ability to predict ACL injuries assessed.