Garlic extract enhances bioceramic bone scaffolds through upregulating ALP & BGLAP expression in hMSC-monocyte co-culture.

Bone homeostasis is predicated by osteoblast and osteoclast cell cycles where gene expressions are responsible for their differentiation from human mesenchymal stem cells (hMSC) and monocytes, respectively. The pro-osteogenic potential of an hMSC-monocyte co-culture can be measured through complementary DNA (mRNA synthesis) within the nucleus, known as quantitative polymerase chain reaction (qPCR). Through this technique, the effects of garlic extract (allicin) release from calcium phosphate bone scaffolds on gene expression of bone forming and bone remodeling cells was explored. Results show this complex biomaterial system enhances hMSC differentiation through the upregulation of bone-forming proteins. Osteoblastic gene markers alkaline phosphatase (ALP) and osteocalcin (BGLAP), are respectively upregulated by 3-fold and 1.6-fold by day 14. These mature osteoblasts then upregulate the receptor activator of nuclear factor-kB ligand (RANKL) which recruits osteoclast cells, as captured by a nearly 2-fold higher osteoclast expression of tartrate-resistance acid-phosphatase (ACP5). This also activates antagonist osteoprotegerin (OPG) expression in osteoblasts, decreasing osteoclast resorption potential and ACP5 expression by day 21. The pro-osteogenic environment with garlic extract release is further quantified by a 4× increase in phosphatase activity and visibly captured in immunofluorescent tagged confocal images. Also corroborated by enhanced collagen formation in a preliminary in vivo rat distal femur model, this work collectively reveals how garlic extract can enhance bioceramic scaffolds for bone tissue regenerative applications.

Quantifying the relationship between cell proliferation and morphology during development of the face.

Morphogenesis requires highly coordinated, complex interactions between cellular processes: proliferation, migration, and apoptosis, along with physical tissue interactions. How these cellular and tissue dynamics drive morphogenesis remains elusive. Three dimensional (3D) microscopic imaging poses great promise, and generates elegant images. However, generating even moderate through-put quantified images is challenging for many reasons. As a result, the association between morphogenesis and cellular processes in 3D developing tissues has not been fully explored. To address this critical gap, we have developed an imaging and image analysis pipeline to enable 3D quantification of cellular dynamics along with 3D morphology for the same individual embryo. Specifically, we focus on how 3D distribution of proliferation relates to morphogenesis during mouse facial development. Our method involves imaging with light-sheet microscopy, automated segmentation of cells and tissues using machine learning-based tools, and quantification of external morphology via geometric morphometrics. Applying this framework, we show that changes in proliferation are tightly correlated to changes in morphology over the course of facial morphogenesis. These analyses illustrate the potential of this pipeline to investigate mechanistic relationships between cellular dynamics and morphogenesis during embryonic development.

Immersive educational curriculum on intracoronary optical coherence tomography image analysis among naïve readers.

BACKGROUND: Optical coherence tomography (OCT) is an intravascular imaging modality for analysing coronary vessels. Image interpretation remains an obstacle for novice readers due to technical artefacts and uncertainty in tissue characterization. Despite an expanding clinical and research role for OCT, few training efforts exist, and there is an absence of a national standardized educational curriculum. We sought to determine whether an interactive, feedback-based OCT curriculum improved image interpretation among naive readers. METHODS: Naive OCT readers completed both a Standard curriculum, comprised of self-directed didactics and consensus statements, and an Augmented curriculum, which provided real-time digital feedback of feature identification and measurements. Modules were separated by a minimum one-week washout period. After each module, and blinded to the exam answers, subjects completed an identical expert-designed 413-item exam to assess technical knowledge and ability to identify and measure vessel features. Performances were compared using Exact Wilcoxon signed-rank tests. RESULTS: Among the 7 included subjects were 3 medical students, 3 internal medicine residents, and 1 cardiovascular medicine fellow with no prior OCT experience. The technical knowledge score (maximum 13) was significantly higher with the Augmented compared with the Standard curriculum (median 11 vs. 7, p = 0.03). After undergoing the Augmented curriculum, all 7 subjects were able to identify features of plaque rupture (Standard curriculum: 5/7 subjects, p = 0.5) and macrophages (Standard curriculum: 6/7 subjects, p = 0.99), differentiate the components between red and white thrombus (Standard curriculum: 6/7 subjects, p = 0.99), and characterize lipid plaque by attenuation, signal, homogeneity, and borders (Standard curriculum: 5/7 subjects, p = 0.5). Performances on the remaining exam portions did not differ between curricula. CONCLUSIONS: The need for standardized, effective training in OCT image interpretation is increasingly essential as the intravascular imaging modality becomes widely utilized among interventional cardiologists and trainees. A novel interactive OCT curriculum enhanced naive readers' technical knowledge and may supplement traditional self-learning in refining analytic skills.

Segmentation of Tissues and Proliferating Cells in Light-Sheet Microscopy Images of Mouse Embryos Using Convolutional Neural Networks.

A variety of genetic mutations affect cell proliferation during organism development, leading to structural birth defects. However, the mechanisms by which these alterations influence the development of the face remain unclear. Cell proliferation and its relation to shape variation can be studied using Light-Sheet Microscopy (LSM) imaging across a range of developmental time points using mouse models. The aim of this work was to develop and evaluate accurate automatic methods based on convolutional neural networks (CNNs) for: (i) tissue segmentation (neural ectoderm and mesenchyme), (ii) cell segmentation in nuclear-stained images, and (iii) segmentation of proliferating cells in phospho-Histone H3 (pHH3)-stained LSM images of mouse embryos. For training and evaluation of the CNN models, 155 to 176 slices from 10 mouse embryo LSM images with corresponding manual segmentations were available depending on the segmentation task. Three U-net CNN models were trained optimizing their loss functions, among other hyper-parameters, depending on the segmentation task. The tissue segmentation achieved a macro-average F-score of 0.84, whereas the inter-observer value was 0.89. The cell segmentation achieved a Dice score of 0.57 and 0.56 for nuclear-stained and pHH3-stained images, respectively, whereas the corresponding inter-observer Dice scores were 0.39 and 0.45, respectively. The proposed pipeline using the U-net CNN architecture can accelerate LSM image analysis and together with the annotated datasets can serve as a reference for comparison of more advanced LSM image segmentation methods in future.

Beta-phase Stabilization and Increased Osteogenic Differentiation of Stem Cells by Solid-State Synthesized Magnesium Tricalcium Phosphate.

In this study, magnesium and strontium-doped ß-tricalcium phosphates were synthesized to understand dopant impact on substrate chemistry and morphology, and proliferation and osteogenic differentiation of mesenchymal stem cells. Under solid-state synthesis, magnesium doping stabilized the ß-phase in tricalcium phosphate, with 22% less α-phase content than control. Strontium doping increased α-phase formation by 17%, and also resulted in greater surface porosity, leading to greater crystal precipitation in vitro. Magnesium also significantly enhanced the proliferation of stem cells (P < 0.05) and differentiation into osteoblasts with increased alkaline phosphatase production (P < 0.05) at all time points. These results indicated that magnesium stabilizes ß-tricalcium phosphate in vitro and enhanced early and late-time-point osteoconduction and osteoinduction of mesenchymal stem cells.

Enhanced osteogenesis of 3D printed ß-TCP scaffolds with Cissus Quadrangularis extract-loaded polydopamine coatings.

Growing demand in bone tissue replacement has shifted treatment strategy from pursuing traditional autogenous and allogeneic grafts to tissue replacement with bioactive biomaterials. Constructs that exhibit the ability to support the bone structure while encouraging tissue regeneration, integration, and replacement represent the future of bone tissue engineering. The present study aimed to understand the osteogenic and mechanical effects of binder jet 3D printed, porous ß-tricalcium phosphate scaffolds modified with a natural polymer/drug coating of polydopamine and Cissus Quadrangularis extract. Compression testing was used to determine the effect the polydopamine coating process had on the mechanical strength of the scaffolds. 3D printed scaffolds with and without polydopamine coatings fractured at 3.88 ± 0.51 MPa and 3.84 ± 1 MPa, respectively, suggesting no detrimental effect on strength due to the coating process. The osteogenic potential of the extract-loaded coating was tested in vitro, under static and dynamic flow conditions, and in vivo in a rat distal femur model. Static osteoblast cultures indicated polydopamine-coated samples with and without the extract exhibited greater proliferation after 3 days (p < 0.05). Similarly, polydopamine resulted in increased proliferation and alkaline phosphatase expression under dynamic flow, but alkaline phosphatase expression was significantly enhanced (p < 0.05) only in samples treated with the extract. Histological analysis of implanted scaffolds showed substantially more new bone growth throughout the implant pores at 4 weeks post-op in polydopamine and extract-loaded implants compared to pure ß-tricalcium phosphate. These results indicated that implants coated with polydopamine and Cissus Quadrangularis extract facilitated osteoblast proliferation and alkaline phosphatase production and improved early bone formation and ingrowth while maintaining mechanical strength.

Mechanical and biological properties of ZnO, SiO2, and Ag2O doped plasma sprayed hydroxyapatite coating for orthopaedic and dental applications.

In this study, we explored a ternary dopant system utilizing 0.25 wt% ZnO to induce osteogenesis, 0.5 wt% SiO2 to induce angiogenesis, and 2.0 wt% Ag2O to provide secondary infection control within a plasma assisted hydroxyapatite coating for orthopaedic or dental applications. The objective of this study was to understand the effects of ZnO, SiO2, and Ag2O dopants on the mechanical and biological properties of hydroxyapatite (HA) coatings on titanium (Ti). Coatings were deposited using a 30 kW plasma spray system equipped with a supersonic nozzle to produce above standard coating bond strengths of 24 ±â€¯2 MPa on Ti6Al4V and 22 ±â€¯1 MPa on commercially pure Ti substrates. Antibacterial properties were revealed in vitro against E. coli and S. aureus. The ternary dopant system was implanted in 18 male Sprague-Dawley rats with timepoints of 5 and 10 weeks. By week 5, ZnSiAg-HA produced 32% bone mineralization of 68% total bone formation compared to only 11% bone mineralization of 55% total bone formation in the undoped coating. This system can be employed for replacement surgeries and revision surgeries to reduce healing time and enhance osseointegration. STATEMENT OF SIGNIFICANCE: Total hip replacements increased 124% from 2000 to 2010 with an ever-increasing rate due to the rise in average life span and an escalation in surgeries for young patients. Replacement surgeries come with the risk of rejection, poor integration, and infection. This study incorporates biologically relevant metallic oxides of ZnO, SiO2, and Ag2O within a hydroxyapatite coating on titanium deposited using a radio frequency induction plasma spray. A ternary dopant system has not been explored in the current literature and little is known about these particular dopants in vivo. This proposed system can be employed for replacement surgeries to lower healing time and enhance osseointegration between implant and host tissue.

Salivary cortisol profiles of on-call from home fire and emergency service personnel.

Working on-call with a night call resulted in a depressed (lower) cortisol awakening response (CAR) peak and post-awakening cortisol area under the curve with respect to ground (AUCG) the following day compared to when off-call. This may be due to exposure to noise, physical exertion, and stressful events during night callouts. There was no anticipatory effect to working on-call in any of the cortisol measures examined. This study, of male fire and emergency service workers who operate on-call from home, had two aims: (1) examine CAR and diurnal cortisol profile following a night on-call with a call, on-call without a call, and off-call; and, (2) explore whether there is an anticipatory effect of working on-call from home on diurnal cortisol profiles. Participants wore activity monitors, completed sleep and work diaries and collected seven saliva samples a day (0 min, 30 min, 60 min, 3 h, 6 h, 9 h, and 12 h after final awakening) for one week. CAR peak, reactivity and area under the curve with respect to increase (AUCI), post-awakening cortisol AUCG, diurnal cortisol slope and AUCG, and mean 12-h cortisol concentrations were calculated. The final analysis included 26 participants for Aim 1 (22 off-call nights, 68 nights on-call without a call, and 20 nights on-call with a call) and 14 participants for Aim 2 (25 days leading up to a night off-call and 92 days leading up to a night on-call). Generalized estimating equations models were constructed for each variable of interest. Aim 1: CAR peak and post-awakening cortisol AUCG were 8.2 ± 3.4 nmol/L and 5.7 ± 2.4 units lower, respectively, following a night on-call with a call compared to an off-call night. Aim 2: the day before a night on-call was not a significant predictor in any model. The lower CAR peak and post-awakening cortisol AUCG following a night on-call with a call compared to following an off-call night may be due to exposure to noise, physical exertion, and stressful events during night callouts. The lack of difference between the day before a night on-call and the day before an off-call night suggests there may not be an anticipatory effect on cortisol when on-call from home.

[Environmental tobacco smoke is a risk factor for the development of chronic obstructive pulmonary disease].

The purpose of this review is to summarise the existing knowledge of the relationship between exposure to en-vironmental tobacco smoke (ETS) and the development of chronic obstructive pulmonary disease (COPD). A possible causal relationship between ETS and COPD has long been suspected. Prenatal as well as postnatal ETS can reduce the lung function of the child permanently. Albeit the causality is multifactorial, new evidence has emerged since the Surgeon General's report from 2006 and suggests, that ETS is an independent and significant risk factor for developing COPD.

Effects of different protocols of high intensity interval training for VO2max improvements in adults: A meta-analysis of randomised controlled trials.

OBJECTIVES: To examine the effects of different protocols of high-intensity interval training (HIIT) on VO2max improvements in healthy, overweight/obese and athletic adults, based on the classifications of work intervals, session volumes and training periods. DESIGN: Systematic review and meta-analysis. METHODS: PubMed, Scopus, Medline, and Web of Science databases were searched up to April 2018. Inclusion criteria were randomised controlled trials; healthy, overweight/obese or athletic adults; examined pre- and post-training VO2max/peak; HIIT in comparison to control or moderate intensity continuous training (MICT) groups. RESULTS: Fifty-three studies met the eligibility criteria. Overall, the degree of change in VO2max induced by HIIT varied by populations (SMD=0.41-1.81, p<0.05). When compared to control groups, even short-intervals (≤30s), low-volume (≤5min) and short-term HIIT (≤4weeks) elicited clear beneficial effects (SMD=0.79-1.65, p<0.05) on VO2max/peak. However, long-interval (≥2min), high-volume (≥15min) and moderate to long-term (≥4-12weeks) HIIT displayed significantly larger effects on VO2max (SMD=0.50-2.48, p<0.05). When compared to MICT, only long-interval (≥2min), high-volume (≥15min) and moderate to long-term (≥4-12weeks) HIIT showed beneficial effects (SMD=0.65-1.07, p<0.05). CONCLUSIONS: Short-intervals (≤30s), low-volume (≤5min) and short-term (≤4weeks) HIIT represent effective and time-efficient strategies for developing VO2max, especially for the general population. To maximize the training effects on VO2max, long-interval (≥2min), high-volume (≥15min) and moderate to long-term (≥4-12weeks) HIIT are recommended.

Longitudinal Analysis of Tactical Strategy in the Men's Division of the Ultimate Fighting Championship.

This study explored longitudinal changes in contemporary mixed martial arts (MMA) combat within the Ultimate Fighting Championship (UFC). A secondary aim was to investigate how bout duration influences the contribution of performance indicators on outcome. Data were acquired via the official analytics provider to the UFC (FightMetric). Male fights with a winner from between 2000 and 2015 (n = 2,831) were examined, with 13 common performance indicators attained during each round for each participant along with duration (min) and year of fight. Non-metric dimensional scaling (nMDS) was used to examine bout characteristics by year. The Repeated Incremental Pruning to Produce Error Reduction (RIPPER) algorithm was run to determine a set of rules to explain bout outcome. The nMDS displayed that winning bout performance indicator attributes were dissimilar across the years. Eight rules were generated from the RIPPER, with fight duration featuring in three of eight rules. Distinct shifts occurred (albeit without linear trend) in performance indicator characteristics during the observed period. This was characterized by a more diverse combat style in the years following 2008. However, offensive grappling has remained a key factor regardless of year, and is influenced by bout duration.

Enhanced In Vivo Bone and Blood Vessel Formation by Iron Oxide and Silica Doped 3D Printed Tricalcium Phosphate Scaffolds.

Calcium phosphate (CaP) ceramics show significant promise towards bone graft applications because of the compositional similarity to inorganic materials of bone. With 3D printing, it is possible to create ceramic implants that closely mimic the geometry of human bone and can be custom-designed for unusual injuries or anatomical sites. The objective of the study was to optimize the 3D-printing parameters for the fabrication of scaffolds, with complex geometry, made from synthesized tricalcium phosphate (TCP) powder. This study was also intended to elucidate the mechanical and biological effects of the addition of Fe+3 and Si+4 in TCP implants in a rat distal femur model for 4, 8, and 12 weeks. Doped with Fe+3 and Si+4 TCP scaffolds with 3D interconnected channels were fabricated to provide channels for micronutrients delivery and improved cell-material interactions through bioactive fixation. Addition of Fe+3 into TCP enhanced early-stage new bone formation by increasing type I collagen production. Neovascularization was observed in the Si+4 doped samples after 12 weeks. These findings emphasize that the additive manufacturing of scaffolds with complex geometry from synthesized ceramic powder with modified chemistry is feasible and may serve as a potential candidate to introduce angiogenic and osteogenic properties to CaPs, leading to accelerated bone defect healing.

The development of a tournament preparation framework for competitive golf: A Delphi study.

Tournament preparation in golf is used by players to increase course knowledge, develop strategy, optimise playing conditions and facilitate self-regulation. It is not known whether specific behaviours in tournament preparation should be given priority in education and practice at different stages of competition. This study aimed to achieve consensus on the importance of specific tournament preparation behaviours or "items" to players of five competitive levels. A two-round Delphi study was used, including an expert panel of 36 coaches, high-performance staff, players and academics. Participants were asked to score the relative importance of 48 items to players using a 5-point Likert-type scale. For an item to achieve consensus, 67% agreement was required in two adjacent score categories. Consensus was reached for 46 items and these were used to develop a ranked framework for each competitive level. The developed framework provides consensus-based guidelines of the behaviours that are perceived as important in tournament preparation. This framework could be used by national sport organisations to guide the development of more comprehensive learning environments for players and coaches. It could also direct future studies examining the critical behaviours for golfers across different competitive levels.

Effects of Lifestyle on Muscle Strength in a Healthy Danish Population.

BACKGROUND: Lifestyle is expected to influence muscle strength. This study aimed at assessing a possible relationship between smoking, alcohol intake and physical activity, and muscle strength in a healthy Danish population aged 20-79 years. Population study based on data collected from The Copenhagen City Heart Study (CCHS) and measurements of Isokinetic muscle strength from a sub-study of randomly selected healthy participants from CCHS. METHODS: 126 women and 63 men were studied. All participants completed a questionnaire regarding their lifestyle, including physical activity, alcohol intake and smoking habits. Isokinetic muscle strength was measured over the upper extremities (UE), trunk, and lower extremities (LE). Multivariate analyses including all of the variables were carried out. RESULTS: The level of daily physical activity during leisure was positively correlated to muscle strength in the lower extremities (p = 0.03) for women, and lower extremities (p = 0.03) and trunk (p = 0.007) for men. Alcohol Intake was in general not correlated to muscle strength. No clear effect of smoking was seen on muscle strength. CONCLUSION: Our results show that physical activity during leisure is associated with a positive effect on muscle strength in both sexes. When keeping alcohol intake within the recommended limits, alcohol does not seem to affect muscle strength negatively. No effect of smoking on muscle strength was found in our group of healthy subjects. The findings are of importance when considering recommendation on life style when wishing to keeping fit with age to be able to carry out daily activities.

Surface modification of biomaterials and biomedical devices using additive manufacturing.

The demand for synthetic biomaterials in medical devices, pharmaceutical products and, tissue replacement applications are growing steadily due to aging population worldwide. The use for patient matched devices is also increasing due to availability and integration of new technologies. Applications of additive manufacturing (AM) or 3D printing (3DP) in biomaterials have also increased significantly over the past decade towards traditional as well as innovative next generation Class I, II and III devices. In this review, we have focused our attention towards the use of AM in surface modified biomaterials to enhance their in vitro and in vivo performances. Specifically, we have discussed the use of AM to deliberately modify the surfaces of different classes of biomaterials with spatial specificity in a single manufacturing process as well as commented on the future outlook towards surface modification using AM. STATEMENT OF SIGNIFICANCE: It is widely understood that the success of implanted medical devices depends largely on favorable material-tissue interactions. Additive manufacturing has gained traction as a viable and unique approach to engineered biomaterials, for both bulk and surface properties that improve implant outcomes. This review explores how additive manufacturing techniques have been and can be used to augment the surfaces of biomedical devices for direct clinical applications.

Salivary alpha amylase in on-call from home fire and emergency service personnel.

The effect of working on-call from home on the sympatho-adrenal medullary system activity is currently unknown. This study had two aims, Aim 1: examine salivary alpha amylase awakening response (AAR) and diurnal salivary alpha amylase (sAA) profile in fire and emergency service workers who operate on-call from home following a night on-call with a call (NIGHT-CALL), a night on-call without a call (NO-CALL) and an off-call night (OFF-CALL), and Aim 2: explore whether there was an anticipatory effect of working on-call from home (ON) compared to when there was an off-call (OFF) on the diurnal sAA profile. Participants wore activity monitors, completed sleep and work diaries and collected seven saliva samples a day for one week. AAR area under the curve with respect to ground (AUCG), AAR area under the curve with respect to increase (AUCI), AAR reactivity, diurnal sAA slope, diurnal sAA AUCG and mean 12-h sAA concentrations were calculated. Separate generalised estimating equation models were constructed for each variable of interest for each aim. For Aim 1, there were no differences between NIGHT-CALL or NO-CALL and OFF-CALL for any response variable. For Aim 2, there was no difference between any response variable of interest when ON the following night compared to when OFF the following night (n = 14). These findings suggest that there is no effect of working on-call from home on sAA, but should be interpreted with caution, as overnight data were not collected. Future research, using overnight heart rate monitoring, could help confirm these findings.

Effects of MgO and SiO2 on Plasma-Sprayed Hydroxyapatite Coating: An in Vivo Study in Rat Distal Femoral Defects.

Plasma-sprayed hydroxyapatite (HA)-coated titanium implants have been widely used in orthopedic applications due to their inheritance of an excellent mechanical property from titanium and great osteoconductivity from HA. However, the lack of osteoinductivity limits their further applications. In this study, 1 wt % MgO and 0.5 wt % SiO2 were mixed with HA for making plasma-sprayed coatings on titanium implants. Plasma-sprayed HA- and MgO/SiO2-HA-coated titanium implants showed adhesive bond strengths of 25.73 ± 1.92 and 23.44 ± 2.89 MPa, respectively. The presence of MgO and SiO2 significantly increased the osteogenesis, osseointegration, and bone mineralization of HA-coated titanium implants by the evaluation of their histomorphology after 6, 10, and 14 weeks of implantation in rat distal femoral defects. Implant pushout tests also showed a shear modulus of 149.83 ± 3.69 MPa for MgO/SiO2-HA-coated implants after 14 weeks of implantation, compared to 52.68 ± 10.41 MPa for uncoated implants and 83.92 ± 3.68 MPa for pure HA-coated implants; These are differences in the shear modulus of 96% and 56.4%, respectively. This study assesses for the first time the quality of the bone-implant interface of induction plasma-sprayed MgO and SiO2 binary-doped HA coatings on load-bearing implants compared to bare titanium and pure HA coatings in a quantitative manner. Relating the osseointegration and interface shear modulus to the quality of implant fixation is critical to the advancement and implementation of HA-coated orthopedic implants.

Confirming the Value of Swimming-Performance Models for Adolescents.

PURPOSE: To evaluate the efficacy of existing performance models to assess the progression of male and female adolescent swimmers through a quantitative and qualitative mixed-methods approach. METHODS: Fourteen published models were tested using retrospective data from an independent sample of Dutch junior national-level swimmers from when they were 12-18 y of age (n = 13). The degree of association by Pearson correlations was compared between the calculated differences from the models and quadratic functions derived from the Dutch junior national qualifying times. Swimmers were grouped based on their differences from the models and compared with their swimming histories that were extracted from questionnaires and follow-up interviews. RESULTS: Correlations of the deviations from both the models and quadratic functions derived from the Dutch qualifying times were all significant except for the 100-m breaststroke and butterfly and the 200-m freestyle for females (P < .05). In addition, the 100-m freestyle and backstroke for males and 200-m freestyle for males and females were almost directly proportional. In general, deviations from the models were accounted for by the swimmers' training histories. Higher levels of retrospective motivation appeared to be synonymous with higher-level career performance. CONCLUSION: This mixed-methods approach helped confirm the validity of the models that were found to be applicable to adolescent swimmers at all levels, allowing coaches to track performance and set goals. The value of the models in being able to account for the expected performance gains during adolescence enables quantification of peripheral factors that could affect performance.

Red, Amber, or Green? Athlete Monitoring in Team Sport: The Need for Decision-Support Systems.

Decision-support systems are used in team sport for a variety of purposes including evaluating individual performance and informing athlete selection. A particularly common form of decision support is the traffic-light system, where color coding is used to indicate a given status of an athlete with respect to performance or training availability. However, despite relatively widespread use, there remains a lack of standardization with respect to how traffic-light systems are operationalized. This paper addresses a range of pertinent issues for practitioners relating to the practice of traffic-light monitoring in team sports. Specifically, the types and formats of data incorporated in such systems are discussed, along with the various analysis approaches available. Considerations relating to the visualization and communication of results to key stakeholders in the team-sport environment are also presented. In order for the efficacy of traffic-light systems to be improved, future iterations should look to incorporate the recommendations made here.

Relationships Between Internal and External Training Load in Team-Sport Athletes: Evidence for an Individualized Approach.

PURPOSE: The aim of this study was to quantify and predict relationships between rating of perceived exertion (RPE) and GPS training-load (TL) variables in professional Australian football (AF) players using group and individualized modeling approaches. METHODS: TL data (GPS and RPE) for 41 professional AF players were obtained over a period of 27 wk. A total of 2711 training observations were analyzed with a total of 66 ± 13 sessions/player (range 39-89). Separate generalized estimating equations (GEEs) and artificial-neural-network analyses (ANNs) were conducted to determine the ability to predict RPE from TL variables (ie, session distance, high-speed running [HSR], HSR %, m/min) on a group and individual basis. RESULTS: Prediction error for the individualized ANN (root-mean-square error [RMSE] 1.24 ± 0.41) was lower than the group ANN (RMSE 1.42 ± 0.44), individualized GEE (RMSE 1.58 ± 0.41), and group GEE (RMSE 1.85 ± 0.49). Both the GEE and ANN models determined session distance as the most important predictor of RPE. Furthermore, importance plots generated from the ANN revealed session distance as most predictive of RPE in 36 of the 41 players, whereas HSR was predictive of RPE in just 3 players and m/min was predictive of RPE in just 2 players. CONCLUSIONS: This study demonstrates that machine learning approaches may outperform more traditional methodologies with respect to predicting athlete responses to TL. These approaches enable further individualization of load monitoring, leading to more accurate training prescription and evaluation.