Training Load Research Articles

Monitoring of Training Load and Body Composition in Elite Male Kayakers

Background: Elite kayaking demands peak conditioning, and tracking these athletes reveals the science behind world-class performance. Physiological demands and body composition changes in elite male kayakers were tracked during the preparatory and transition periods of a kayaking competitive season. Methods: Laboratory (body composition assessment and a 4 min all-out test in a kayak ergometer) on-field tests (4 × 1500 m incremental intermittent protocol with 30 s rest intervals in a kayaking/rowing track) were applied on separate days to follow eight elite male kayakers (23.1 ± 5.6 y; 80 ± 8.8 kg; 177.0 ± 6.8 cm) at the beginning of the kayaking season (preparatory period, M1; first week of October), 22 weeks later, at the beginning of the transition period (M2; last week of February), and 5 weeks later, at the end of the transition period, i.e., beginning of the competitive period of the season (M3; first week of April). M3 corresponded to the participation in international competitions. Results: Distance at peak oxygen uptake (V˙O2peak) on the kayak ergometer improved by 36.7 m from M1 to M3, the pace at V4 (aerobic capacity) was reduced (improved) by 25.2 s·km−1 from M1 to M2, and 25.6 s·km−1 by M3. Body weight decreased by 2.3 kg from M1 to M2, and fat mass percentage and kilograms decreased by 1.8% and 3.1%, respectively. Fat-free mass increased by 1.9% and 3.1%, respectively. Skinfold measurements showed a decrease in subscapular, suprailiac, abdominal, and geminal skinfold. Aerobic power (V˙O2peak) in absolute values (in L·min−1) improved by 0.7 L·min−1 from M1 to M2, and by 1.1 L·min−1 by M3, and from M2 to M3 was ~0.5 L·min−1. Aerobic power in relative values improved by 15.0 from M1 to M2, and by 6.4 mL·kg−1·min−1 from M2 to M3. Conclusions: Elite male kayakers improved their physiological performance and body composition during the preparatory and transition phases of the competitive season. Notable gains in performance were mainly due to enhanced aerobic power, and positive body composition changes. These findings provide insights for optimizing training strategies and boosting competitive performance.

Analysis on Flexural Performance of Prestressed Steel-Reinforced UHPC Beams

The flexural performance of prestressed steel-reinforced ultra-high-performance concrete (UHPC) beams was investigated through finite element (FE) modeling and nonlinear numerical analysis. Two FE models were established for prestressed steel-reinforced concrete beams and prestressed UHPC beams, respectively, and the accuracy was validated by comparing with the experimental results. On this basis, a comprehensive analysis of load–deflection behavior, load–strain relationships, and failure modes was conducted under varying parameters, including reinforcement ratio, prestress level, steel web thickness, and steel flange thickness. The results indicate that an increase in reinforcement ratio from 1.17% to 1.90% enhanced the ultimate load by 12.05%, while increasing the prestress level from 0.61 to 0.76 improved the cracking load by 114.88% and the ultimate load by 53.73%. Moreover, the beams exhibited superior ductility and cracking resistance compared to conventional concrete structures. A formula for predicting the flexural capacity of prestressed steel-reinforced UHPC beams was derived, showing an average error of less than 3% when compared with FE simulations. This formula provides a reliable basis for the structural design and optimization of high-performance composite beams in engineering practice.

Effects of intermittent fasting and sports performance: a narrative review

Recently, fasted exercise has generated interest for its potential to stimulate metabolic and performance adaptations. The present study aims to analyze the effects of fasting and fasted training on performance and metabolism, acutely and chronically. The databases Medline (PubMed), Physiotherapy Evidence Database (PEDro), Cochrane, and Google Scholar were searched. In total, 767 studies were identified. Of those, 51 studies were finally included. Acutely, exercise on fasting promotes fat oxidation at low and moderate intensities, while protein catabolism is not increased. Performance is not affected in efforts lower than 1 hour. Chronically, fasting generates greater efficiency in fat metabolism and the ability to regulate blood glucose in the long term, although it has not been possible to determine whether these findings improve sports performance. More research is needed in elite athletes, with high training loads and with a periodized approach to fasting.

Influence of puberty stage in immune-inflammatory parameters in well-trained adolescent soccer-players, following 8-weeks of pre-seasonal preparation training

Aim: The immune system can experience temporary suppression following acute or prolonged strenuous exercise, potentially increasing susceptibility to infections. Young athletes, who must balance school, training, studies, and social life, may further disrupt their immune-inflammatory responses. This study aimed to investigate the effects of an 8-week pre-season training on circulating leukocyte responses in well-trained adolescent soccer-players at different stages of puberty. Methods: Thirty-six soccer players, divided into two groups based on their biological age-under sixteen (U16) and above sixteen (A16)-underwent two rounds of assessments. These included evaluations of anthropometrics, physical fitness, and immune parameters before and after an 8-week pre-season soccer training program. Results: No significant treatment or interaction effects were found for erythrocyte sedimentation rate (ESR), platelets, total leucocyte count, immune inflammation markers (IIM), weekly rating of perceived exertion, body composition, sit-and-reach flexibility, or VO2max (P > 0.05). However, post-intervention neutrophil counts were increased, while lymphocyte counts decreased, and IIM levels rose in both groups (P < 0.05). Neuromuscular explosiveness and strength endurance were significantly higher in the A16 group compared to the U16 group (P < 0.05). Body fat was reduced, and all physical fitness parameters improved in both groups over time (P < 0.05). Conclusions: The 8-week soccer-specific training program did not lead to different effects on immune-inflammatory parameters between youth soccer players at different stages of puberty. However, training adaptations, including improvements in physical fitness, were observed in both groups. This suggests that when the same training load (frequency, duration, intensity) is applied to adolescents at different stages of puberty, immune-inflammatory responses are not significantly influenced by age, but physical fitness improves regardless of puberty stage. A key limitation of this study is the lack analysis of lymphocyte subpopulations, which could provide a deeper understanding of the cellular effects of training on immune function.

Relationship of Individual Athlete External Load, Session Rating of Perceived Exertion, and Athlete Playing Status Across a Collegiate Women’s Basketball Season

External (EL) and internal (IL) load are commonly used methods used to quantify training load in team sports. Playing time and playing position may influence the training loads for specific athletes throughout a season. The purpose of the current study was to evaluate the effect of athlete playing status and individual in-season practices on EL and IL across a collegiate women’s basketball season. Female basketball athletes were classified as high-minute (HMA; ≥15 min/game) or low-minute (LMA; <15 min/game) and wore microsensors during 53 practices for a total of 583 data points. EL was obtained via an inertial measurement unit (IMU) device that contained a triaxial accelerometer to obtain three-dimensional positioning data. IL and strength training (ST) load were determined via session rating of perceived exertion (sRPE) to create a daily summated value. Descriptive statistics indicate that athletes experienced individual differences in EL, ST, and IL throughout the season. A growth model showed that HMAs experienced higher EL than LMAs at the start of the season for practices (90.21 AU). Across all athletes, IL increased across the season (40.11 AU) and for each 1 unit of change in EL, IL increased by 1.04 AU. Repeated measures correlations identified a large relationship between IL and EL (r = 0.51, p < 0.001). A location-scale model indicated that the within-person variability of IL across all athletes was 3.29 AU but was not due to athlete playing status. It is recommended to base in-season training on individual loads and game demands to promote athlete readiness and improved sport performance.

Machine learning-based prediction model for sports injury risk in biomechanics: A case study of joint injuries in basketball at a university in Xi’an

Basketball players are prone to joint injuries due to the sport’s high intensity and physical demands. Early prediction of injury risk is crucial for implementing effective prevention strategies. Incorporating biomechanics, this study focuses on basketball players at a university in Xi’an, China, aiming to develop a machine learning-based model to predict joint injury risk using easily collectable data such as training load, fatigue levels, and previous injury history. Considering regional differences, we observed that local and northern Chinese students are generally taller, while students from southern China are typically shorter. This anthropometric variation was included in our sampling and analysis. Utilizing data from 100 basketball players, the Random Forest algorithm achieved the best predictive performance with an accuracy of 85%. Key risk factors identified include high training load, elevated subjective fatigue scores, and a history of previous joint injuries. Additionally, biomechanical data were integrated to elucidate the underlying mechanisms of joint injuries, and the cellular responses to injury were explored. The results demonstrate that even with limited data types, machine learning methods can effectively predict joint injury risk among basketball players, providing a valuable tool for injury prevention.

Development of a web-based tool to assess daily rating of perceived exertion in agility dogs

ObjectiveTo develop a web-based tool for daily use by agility handlers to log rating of perceived exertion (RPE) for dogs as an aid in quantifying daily exercise and training load and to improve training and conditioning strategies.ProceduresFocus group meetings with small groups of handlers were conducted via internet—based video conferencing using a semi-structured interview format. Meeting notes were coded for reflexive thematic analysis. The RPE logging tool was revised based on handler feedback. Each handler was asked to log their dog’s daily RPE data for 1 week. Data were analyzed to assess compliance and timeliness of entries. Participants completed a post-logging questionnaire to provide feedback about their experiences.ResultsEighteen agility dog handlers participated in all phases of the project. Handler and dog demographics were similar to previously reported demographics of agility participants in the United States. Reflexive thematic analysis of their comments related to the initial draft RPE logging tool yielded 3 initial themes, all of which supported a fourth and major theme: the need for specific and detailed training resources before agility handlers utilized the RPE tool. Of 18 handlers, 14 (78%) submitted logging records for the full week. Median time for data entry was 87 s (IQR = 56–117 s), and 92% of logging records were entered within 1 day of the events which were being recorded. In the follow-up questionnaire the handlers did not identify any major concerns. Based on all available data from the handlers, a final version of the RPE logging tool was produced.Conclusion and clinical relevanceAgility dog handlers are very interested in developing and validating tools to quantify training load for their dogs. The final RPE logging tool was quick and easy to use. Further validation of this logging tool is required with a larger number of handlers and comparison to physiologic data from exercising dogs.

Immune inflammation markers and physical fitness during a congested match play period in elite male soccer players

Background/ObjectiveCellular immune markers of inflammation such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune inflammation index (SII) are frequently used in patient care. The adoption of these markers to elite sports, e.g. soccer could be beneficial when monitoring training and aiming to maximize physical fitness. This study investigated cellular immune inflammation markers and physical fitness in elite male soccer players in relation to changes in training and match exposure during a congested match play period.MethodsFifteen elite male soccer players were evaluated three times (T1, T2, and T3) over 12 weeks (T1–T2: six weeks uncongested period of match play and T2–T3: six weeks congested period of match play). Players performed vertical jump tests (squat jumps [SJ], countermovement jumps [CMJ]), the 20-meter sprint test, and the Yo-Yo intermittent recovery test (YYIRL1) at T1, T2 and T3. Measurements included counts of leucocytes and its subtypes, as well as platelets. Cellular immune inflammation markers (NLR, PLR and SII) were calculatedat T1, T2, and T3. Training session rating of perceived exertion was also recorded on a daily basis.ResultsSignificant increases in leucocyte, neutrophil, eosinophil, basophil and monocyte counts occurred at T3 compared with T2 (0.002 < p < 0.04, -0.56 < ES < -0.40) and T1 (-0.78 < ES < -0.49). Lymphocyte counts were lower at T3 as compared to T2 and T1 (p = 0.038, -0.48 < ES <-0.25), while NLR, PLR and SII were greater at T3 compared to T2 (0.001 < p < 0.015, -1.01 < ES < -0.44) and T1 (-0.99 < ES < -0.21). There was a negative correlation between YYIRL1 performance with NLR (r= -0.56; p = 0.02), PLR (r=-0,44, p = 0.015), and SII (r= -0.63; p = 0.01) after the congested period of match play (i.e., T3). Values for maximal oxygen uptake (VO2max), estimated from the YYIRL1 test, negatively correlated with NLR (r= -0.56; p = 0.02), PLR (r=-0,44, p = 0.015), and SII (p = 0.01; r= -0.63). There was a positive correlation between NLR, and SII with workload parameters. In addition, a clear positive correlation was observed between NLR and SII with competitive loadinstead (r= [0.59–0.64; p˂ 0.001), training load (TL) (r= [0.65–0.68]; p˂ 0.001), session rating of perceived exertion (S-RPE) (r= [0.65–0.68]; p = 0.001), and training volume (r= [0.60–0.61; p = 0.001).ConclusionAn intensive period of congested match play significantly alterated immune cell counts and cellular markers of inflammation (NLR, PLR and SII). Changes in NLR and SII were related to workload parameters, suggesting the usefulness of these markers in regulating training intensity and competitive load. An association between physical fitness (YYIRL1, VO2max) and NLR, PLR and SII suggests that these biomarkers are promising tools to monitor aerobic physical fitness of elite soccer players during congested periods of match play.

A microcycle of high-intensity short-interval sessions induces improvements in indicators of endurance performance compared to regular training.

The purpose of this study was to evaluate the effects of a microcycle of high-intensity interval training (HIT) sessions with multiple short work intervals followed by an active recovery period, compared to a similar duration of regular training, on determinants and indicators of endurance performance in well-trained cyclists. The participants in the BLOCK group performed a 6-day HIT microcycle including five HIT sessions (5×8.75-min 30/15s short intervals) followed by a 6-day active recovery period with reduced training load, while the regular training group (REG) performed 12days of their regular training, including four HIT sessions. Physiological testing was performed before and after the training periods. From pre- to post- intervention, BLOCK demonstrated significantly larger improvements than REG in mean power output (PO) during the last min of the maximal oxygen uptake (VO2max) test (POVO2max) (3.7 vs. 0.7%, p=0.009, and effect size (ES)=1.00) and mean PO during the 10-s sprint (2.8 vs. 1.9%, p=0.028, and ES=0.63). No significant differences between BLOCK and REG were observed for VO2max, PO at 4mmol·L-1 [blood lactate] (PO4mmol), 15-min maximal mean power output (PO15-min), and gross efficiency (p=0.156-0.919). However, there was a tendency for larger improvements in the performance index (calculated from the main performance indicators POVO2max, PO4mmol, and PO15-min) in BLOCK compared to REG (2.9% vs. 1.2%, p=0.079, and ES=0.71). A 6-day high-intensity short-interval microcycle followed by a 6-day active recovery period induces improvements in endurance performance indicators compared to regular training, demonstrating its potential as an efficient strategy for endurance training in well-trained cyclists.

The Effect of Heart Rate Variability Biofeedback on Recovery After Aerobic Exercise.

Recovery is a critical factor in athletic performance, and accelerating this process is essential to enable athletes to perform more effectively in both training load and competitive performance. After exercise, immediate recovery is potentially helpful for investigating autonomic activity levels, as they are definable with heart rate variability (HRV). The purpose of this study was to examine the effect of ten sessions of HRV-Biofeedback (HRV-BF) training on recovery process parameters after the aerobic performance. In this study, twenty-four soccer players aged 18-24 volunteered to participate. The athletes who met the research criteria were divided into an experimental group (n = 12) and a control group (n = 12). Each participant's height, weight, BMI, body fat percentage, and aerobic capacity were measured before and after the 10-session intervention. The experimental group participated in a 10-session HRV-BF training and soccer training program, while the control group only participated in a 10-session soccer training program. Aerobic capacity tests were then applied again to experimental and control group participants. The effect of biofeedback on the three HRV parameters during the 5-minute acute recovery period after the test was investigated. The results showed that regularly applied HRV-BF training can significantly shorten the HRV recovery parameter after exercise. Specifically, the athletes who performed HRV-BF training demonstrated faster cardiovascular recovery after aerobic exercise. This suggests that implementing HRV-BF training for athletes can significantly accelerate their recovery processes during and after competitions. Given recent technological advancements, it is promising to consider adding HRV-BF training to stress management interventions, particularly in relation to physiological stress indicators.

Acute Responses of Low-Load Resistance Exercise with Blood Flow Restriction

Blood flow restriction (BFR) is a popular resistance exercise technique purported to increase metabolic stress and augment training adaptations over time. However, short-term use may lead to acute neuromuscular fatigue and higher exertion ratings. Objective: The purpose of the current study was to examine acute physiological responses to low-load resistance exercise utilizing BFR compared to higher-load, non-BFR resistance exercise. Methods: Recreationally trained males (n = 6) and females (n = 7) (mean ± standard deviation, age: 20 ± 1 yrs.; height: 172 ± 8 cm; weight: 73 ± 11 kg; BMI: 24.4 ± 2.2 kg·m−2; training experience: 4 ± 2 yrs.) had limb occlusion pressure determined (50%; right leg: 118 ± 11 mmHg; left leg: 121 ± 13 mmHg) using an automated, self-inflating cuff system during baseline testing. In subsequent sessions, using a randomized, cross-over design, participants completed one of two experimental conditions: (1) Low-load + BFR and (2) High load + non-BFR. In both conditions, participants completed one set of back squats at either 30% (BFR) or 60% (non-BFR) of an estimated 1RM for a max of 30 repetitions, followed by three additional sets with the same loads and a target of 15 repetitions per set. Blood lactate and countermovement jump (CMJ) height were measured pre- and post-back squat. Ratings of perceived exertion (RPE) were assessed following each set. Results: When collapsed across all sets, participants completed significantly more total repetitions in the BFR condition compared to non-BFR (75.0 ± 0.0 vs. 68.23 ± 9.27 reps; p = 0.015; ES: 1.03), but a lower training load volume (2380 ± 728 vs. 4756 ± 1538 kg; p &lt; 0.001; ES: 1.97). There was a significant time-by-condition interaction (p &lt; 0.001), with a greater increase in blood lactate occurring from baseline to post-back squat in the non-BFR condition (11.61 mmol/L, 95%CI: 9.93, 13.28 mmol/L) compared to BFR (5.98 mmol/L, 95%CI: 4.30, 7.65 mmol/L). There was another significant time-by-condition interaction (p = 0.043), with a greater reduction in CMJ occurring in the non-BFR condition (−6.01, 95%CI: −9.14, −2.88 cm; p &lt; 0.001) compared to BFR (−1.50, 95%CI: −1.50, 4.51 cm; p = 0.312). Conclusions: Utilizing a low-load BFR protocol may allow for a higher training volume, yet lower metabolic stress and reduce neuromuscular fatigue compared to lifting at a higher load without the use of BFR.

Research on the gradual change model of vibration characteristics of spatial steel truss structures under fatigue loading

A bottom–up multi-scale performance transfer chain is developed to ascertain the gradual change in the law of vibration characteristics in spatial steel truss structures under fatigue loading. This chain derives the interrelationship between vibration characteristics and the performance of each structural component. Based on the evolution characteristics of the performance model of the member scale in the transfer chain, a new analytical model of the shape function is established. Building on these foundations, a refined model was formulated to depict the gradual change of vibration characteristics in spatial steel truss systems under fatigue loading. This model integrates the cumulative damage rule, the structural residual performance rule, the finite element method and other pertinent theories. The gradual change in vibration characteristics of a steel truss girder bridge subjected to train loads was analyzed using a self-developed three-dimensional finite element analysis framework tailored explicitly for assessing gradual change issues in spatial steel truss structures. The analysis results indicate that the effective residual cross-sectional area and the structural frequency continuously decline as the service time increases. This comprehensive study advances the understanding of fatigue-induced changes in spatial steel truss structures. It offers analytical perspectives for predicting and mitigating the long-term impacts of dynamic loads on large-scale infrastructural components.

Determination of Influence Line for Shield Tunnel Based on Displacement Response under Passing Train Load Measured Using MEMS Accelerometer

Determination of Influence Line for Shield Tunnel Based on Displacement Response under Passing Train Load Measured Using MEMS Accelerometer

The association between subjective sleep and stress in recreational athletes

Subjective sleep and stress are strongly associated, at multiple levels, and the current body of evidence highlights a bi-directional association. Previous research has highlighted that issues with sleep can impact on several stress responses. On the other side of this relationship, research has shown that stress-inducing factors can significantly impact sleep. The present study examined this association in a sample of recreational athletes, a population that has received little to no research focus to date Recreational athletes are defined as individuals who exercise &gt;4 hours per week for health, fitness, or unofficial competitions. Recreational athletes (n = 34) completed online measures of subjective sleep, subjective stress, subjective anxiety/depression and training load (PSQI, PSS, HADS and DALDA). Pearson correlations were carried out to examine associations between variables. There was a significant positive correlation between subjective sleep quality and subjective stress. There was a significant positive correlation between subjective stress and training load. There was a significant positive correlation between subjective sleep quality and training load. The positive associations between sleep, stress and training load are consistent with previous research, but the present study adds to the literature by highlighting the associations in recreational athletes. Recreational athletes should proactively manage their sleep and stress, as due to the bi-directional relationship, improving sleep may benefit stress, and improving stress may benefit sleep quality. This is also likely to benefit overall mood and reduce the likelihood of overtraining in recreational athletes.

Identification of Game Periods and Playing Position Activity Profiles in Elite-Level Beach Soccer Players Through Principal Component Analysis.

Beach soccer has gained increasing interest for study in the sports sciences. In this sense, the analysis of activity profiles is important for training design and load individualization. Therefore, the aims of this study were to identify the most important variables to assess the activity profile and to compare them according to the playing position and game periods in international beach soccer matches. A total of 19 matches of the Spanish national beach soccer team were analyzed during their participation in different international competitions during the 2021-2022 season. A Principal Component Analysis (PCA) was applied to objectively select the external load variables that best explain the data. Kaiser-Meyer-Olkin values of 0.705 and Bartlett's Sphericity (p < 0.01) were obtained. Kruskal-Wallis and Friedman tests was performed for playing positions and game period comparisons, respectively. The PCA showed seven components that grouped a total of 20 variables, explaining 66% of the total variance. Only PC1 and PC2 explained more than 15% (23% and 17%, respectively). Differences were found between playing positions (H > 22.73; p < 0.01) and between game periods (X2 > 16.46; p < 0.01). A significant decrease was found throughout the game, with the highest demands in period 1 and the lowest in period 3. The highest workloads were performed by wingers and the lowest by goalkeepers. The differences between positions and game periods were found in the following: Total Distance (m/min), HIBD (m/min), High Acc (m/s), High Dec (m/s), Acc 1-2 m/s2 (m), Acc 2-3 m/s2 (m), Imp 4-5G (n), Imp 5-6G (n), Sprint (n), and Dec 10-6 m/s2 (m) (p < 0.01). In conclusion, physical and tactical demands faced by elite-level beach soccer players will be influenced by playing positions and game periods. Coaches needs to develop position-specific training programs and optimize substitution strategies for enhancing overall team performance.

Study on dynamic modulus of polyurethane mixture: Impact factors and prediction models

Polyurethane mixture (PUM) is proposed as an innovative and promising paving material due to its superior engineering performance and environmentally-friendliness. This study aims to experimentally investigate dynamic modulus of PUM at various temperatures, loading frequencies and loading strains. Furthermore, prediction models on its dynamic modulus considering factors of temperature, loading frequence as well as their coupling effect are proposed. The results demonstrate that dynamic modulus of PUM approximately varies between 2000 MPa and 19,000 MPa in temperature range of 15–50°C, loading frequency range of 0.1–25 Hz, and loading strains range of 20–100με. Dynamic modulus of PUM at 15°C is approximately 5.62 times higher than that at 50°C. The value at 20 Hz is approximately 2.76 times higher than that at 0.2 Hz. By implementing the analysis of variance (ANOVA) method, it is explored that temperature and loading frequency yield significant impact on dynamic modulus of PUM while loading strain imposes negligible influence on dynamic modulus of PUM. By statistical fitting analysis, dynamic modulus of PUM is linear with temperature and presents power function with loading frequency. Moreover, by considering coupling effect of temperature and loading frequency, prediction model on dynamic modulus of PUM is proposed and verified through experiments. The outcome of this study facilitates design and applications of PUM at different climate conditions and traffic loads.

Exposure misclassification: an “immortal time” bias in observational studies of training load and injury

Several observational studies of the relationship between training load and injury have found increased risks of injury at low loads. These associations are expected because load is often assessed at the end of the injury follow-up period. As such, athletes who get injured earlier in the follow-up period will have systematically lower loads than athletes who get injured later in the follow-up period. In this commentary, we identify this problem as a type of exposure misclassification occurring from the misalignment of exposure measurement and start of follow-up. This methodological issue has previously been recognized in other areas of epidemiology as “immortal time bias”. We discuss how this bias can be prevented by aligning the measurement of load with the start of follow-up for injury.

Operational Influence Line Identification of High-Speed Railway Bridge Considering Uncertainty of Train Load

Operational Influence Line Identification of High-Speed Railway Bridge Considering Uncertainty of Train Load

Experimental study on deformation mechanism around indentation of GH4169 alloy

The GH4169 alloy is widely used in engineering structures due to its excellent high-temperature strength, corrosion resistance, and mechanical properties. However, local stresses during plastic deformation significantly impact its macroscopic mechanical performance. This study investigates the residual deformation fields and plastic deformation mechanisms around local indentations using digital image correlation (DIC), electron backscatter diffraction (EBSD), and nanoindentation. The results show that the indentation rate affects the accumulation of geometrically necessary dislocations (GNDs). Increasing the loading rate from 2mN/s to 20mN/s leads to a 32% increase in GNDs. When the loading strain rate increases from 0.01s-1 to 0.2s-1, GNDs increase by 43%. Moreover, indentations initiate more than two slip systems in the alloy crystals, with slip trace lines consistent with theoretical predictions. The plastic deformation field distribution around the indentations, obtained using DIC, reveals the influence range of slip generation due to indentations to be around 10 μm.

Training loads and practices of competitive organ-recipients at the British and World Transplant Games

Training loads and practices of competitive organ-recipients at the British and World Transplant Games