Performance-enhancing Effects Research Articles

Kratom-From natural remedy to addictive drug and back

Kratom/ketum is apsychoactive herbal preparation that has been used for along time as aremedy and performance-enhancing substance in Southeast Asia. The advancement of globalization is making kratom increasingly more available in the western world, where it is becoming increasingly more used. The current research on kratom and its ingredients is presented. An overview of the use and effects of kratom is exemplary given on the basis of reports. The instrumentalization of the drug and its consequences up to the development of addiction are discussed. Consumption is accompanied by several instrumentalizeable effects so that kratom is used as atherapeutic substance in the self-management of pain, anxiety and depression as well as other substance addictions. Another benefit comes from the performance-enhancing effects on physical work and in a social context. Consumption is usually well controlled, rarely escalates and has few and mostly mild aversive side effects. The danger arises from consumption particularly when there is an escalation of the dose and from mixed consumption with other psychoactive substances. The main alkaloid mitragynine and the more potent 7‑hydroxy-mitragynine are considered mainly responsible for the effect. Both have acomplex pharmacology that involves partial µ‑opioid receptor agonism. Epidemiological, clinical and neurochemical studies have shown that kratom only has alimited addictive drug profile, which might suggest amedical use as aremedy or substitute in addiction treatment.

Potential Benefits of Postactivation Potentiation Protocols on Tennis Performance: A Systematic Review

ABSTRACT The study aimed to provide an overview of the benefits of postactivation potentiation (PAP) protocols on tennis performance. All procedures were in accordance with the PRISMA guidelines. After an online search, 8 studies with 133 tennis players were eligible for inclusion. Results showed that a variety of methods were used to elicit PAP in tennis players, with maximal voluntary isometric contraction showing promising results in improving serve velocity (SV) by 4.6 km·h−1 (3.4 ± 4.6%; ES = 0.711) immediately after the preconditioning activity (PCA). The most favorable effects of PAP on sprinting time and maximal power were observed in resistance training exercises using squats as PCA, with loads near 60% of 1 repetition maximum (1RM), whereas the heavy load leg press warm-up demonstrated positive effects on agility and power. By contrast, negative effects on SV were observed with heavy 600-g ball throws. Despite limitations in match application because of the post-activation performance enhancement effect duration, these protocols remain beneficial for training purposes. Calculating volume load relative to 1RM can provide helpful insights for optimal PAP. However, individualizing PAP protocols based on athletes' characteristics and training status seems crucial and should be investigated in future studies.

Capability configurations for successful advanced servitization

PurposeAdvanced servitization is the process that involves the combination of different services that facilitate both the use of a product and customer operations. Although servitization has emerged as a frequent strategy for manufacturers to differentiate themselves from the competition, its implementation can pose major challenges and may not always result in superior firm performance. Consequently, successful advanced servitization may require specific organizational capabilities to unleash performance-enhancing effects. To date, little is known about how to effectively configure advanced servitization to achieve such performance gains.Design/methodology/approachAdopting a fit theory perspective and using a configurational approach, we examine the interplay between servitization, organizational capabilities, contextual factors and financial performance. Specifically, we focus on advanced servitization and assess its necessity and sufficiency for achieving high financial performance. In addition, we study how the alignment of servitization approaches with organizational capabilities and contextual factors affects financial performance. We analyze data from 151 manufacturers in an emerging economy using fuzzy-set Qualitative Comparative Analysis (fsQCA).FindingsOur findings indicate that advanced servitization is sufficient, but not necessary for high financial performance. In addition, the findings indicate that the alignment of servitization approaches with specific service-related capabilities unfolds complementarity effects that contribute to achieving high financial performance for manufacturers with different firm size and competitive intensity. The findings indicate three configurations that may serve as templates for managers to orchestrate resource allocation and successfully deploy advanced servitization.Originality/valueOur study advances the servitization literature by further illuminating advanced servitization as a more complex servitization process. We show how high-performing manufacturers align servitization and organizational capabilities across different contexts, and thus provide design choices for managers in configuring servitization.

Diurnal biological effects of correlated colour temperature and its exposure timing on alertness, cognition, and mood in an enclosed environment

Artificial lighting, which profits from the non-visual effects of light, is a potentially promising solution to support residents’ psychophysiological health and performance at specific times of the day in enclosed environments. However, few studies have investigated the non-visual effects of daytime correlated colour temperature (CCT) and its exposure timing on human alertness, cognition, and mood. However, the neural mechanisms underlying these effects are largely unknown. The current study evaluated the effects of daytime CCT and its exposure timing on markers of subjective experience, cognitive performance, and cerebral activity in a simulated enclosed environment. Forty-two participants participated a single-blind laboratory study with a 4 within (CCT: 4000 K vs. 6500 K vs. 8500 K vs. 12,000 K) × 2 between (exposure timing: morning vs. afternoon) mixed design. The results showed time of the day dependent benefits of the daytime CCT on subjective experience, vigilant attention, response inhibition, working memory, emotional perception, and risk decisions. The results of the electroencephalogram (EEG) revealed that lower-frequency EEG bands, including theta, alpha, and alpha-theta, were quite sensitive to daytime CCT intervention, which provides a valuable reference for trying to establish the underlying mechanisms that support the performance-enhancement effects of exposure to CCT in the daytime. However, the results revealed no consistent intervention pattern across these measurements. Therefore, future studies should consider personalised optimisation of daytime CCT for different cognitive demands.

DDPG 및 연합학습 기반 5G 네트워크 자원 할당과 트래픽 예측

With the advent of 5G, characterized by Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low Latency Communications (URLLC), and Massive Machine Type Communications (mMTC), efficient network management and service provision are becoming increasingly critical. This paper proposes a novel approach to address key challenges of 5G networks, namely ultra-high speed, ultra-low latency, and ultra-reliability, while dynamically optimizing network slicing and resource allocation using machine learning (ML) and deep learning (DL) techniques. The proposed methodology utilizes prediction models for network traffic and resource allocation, and employs Federated Learning (FL) techniques to simultaneously optimize network bandwidth, latency, and enhance privacy and security. Specifically, this paper extensively covers the implementation methods of various algorithms and models such as Random Forest and LSTM, thereby presenting methodologies for the automation and intelligence of 5G network operations. Finally, the performance enhancement effects achievable by applying ML and DL to 5G networks are validated through performance evaluation and analysis, and solutions for network slicing and resource management optimization are proposed for various industrial applications.

The Impact of ESG Performance on Green Innovation among Traditional Energy Enterprises—Evidence from Listed Companies in China

To address escalating environmental challenges and the energy crisis, traditional energy companies must initiate green transformations and enhance green innovation. ESG (Environmental, Social, and Governance) performance is vital for gauging enterprises’ sustainable development. Therefore, this study explores the relationship between the ESG performance of traditional energy companies and their extent of green innovation. It aims to investigate whether improving ESG performance can lead to enhanced green innovation within these companies. Therefore, this paper employs a fixed effect model to analyze the impact of ESG performance on green innovation among traditional energy companies, specifically focusing on those listed in the Chinese A-share market from 2013 to 2022. The results indicate that ESG performance significantly promotes green innovation within traditional energy companies. The mechanism test’s findings reveal that ESG performance impacts green innovation via three key pathways: innovation investment, external monitoring, and government subsidies. Furthermore, further analysis reveals that the intense market competition environment positively moderates the effect of ESG performance enhancement on the extent of green innovation. This implies that, by improving their ESG performance, traditional energy companies can enhance their green innovation and green transformation efforts. Moreover, this impact is particularly pronounced among state-owned enterprises.

Effects of Eccentric Speed during Front Squat Conditioning Activity on Post-activation Performance Enhancement of Hip and Thigh Muscles.

The phenomenon of post-activation performance enhancement plays an unidentified role in movement eccentric speed and individual muscle group responses. Therefore, this study aimed to determine whether the loaded front squat (FSq) speed of the eccentric phase would influence the post-activation performance enhancement effect and whether the FSq would elicit similar performance enhancement of knee flexion, knee extension, hip flexion, and hip extension muscles. Twenty resistance-trained handball players performed the FSq under maximum eccentric-concentric speed and 2-s eccentric speed (only the eccentric phase performed), while pre- and post-front squat countermovement jump, knee, and hip isokinetic flexion/extension performance were tested. The FSq conditioning activity was performed in a single set of three repetitions with either 90% (maximum eccentric-concentric speed) or 120% (2-s eccentric speed) of one repetition maximum, and post-performance was measured 4-12 min after the FSq. Athletes randomly changed the FSq eccentric speed and tested the hip or knee isokinetic flexion/extension strength at 180°/s. ANOVA showed that the rate of force development during the jump increased (Cohen d = 0.59-0.77) with no differences between 2-s eccentric and maximum speed eccentric protocols. Isokinetic strength increased after the 2-s eccentric FSq in hip extension (d = 0.76-0.86), knee flexion (d = 0.74-0.88), and hip flexion (d = 0.82), with no differences in knee extension strength. After maximum eccentric-concentric speed, isokinetic strength increased in hip extension (d = 1.25). In conclusion, the FSq conditioning activity enhances hip extensors' performance more than knee extensors' performance. Different eccentric types of muscle action during a conditioning activity alter the level of local muscle enhancement.

A Comparative Study of the Experimental Investigation of different types of fibres used in Concrete

Different types of fibres used in concrete have received much attention in civil engineering in recent years, mainly because they improve the low tensile strength and shrinkage cracks of concrete. However, there are still many problems in the research results on different types of Fibers. For example, there is still debate about the performance-enhancing or detrimental effects of different types of fibres in concrete. There is also a dispute about the influence of the size, strength, elastic modulus and other characteristic parameters of each fibre on the properties of the substrate. Research on fibre mixing rules of hybrid fibre reinforced concrete (HFRC) is incomplete. There is controversy regarding the choice of fibres for hybrid yarns as well as the characterization of the hybrid effect. In summary, it is necessary to review, synthesize and compare current research on FRC. Based on the major research achievements on FRC in recent years, this article synthesizes and evaluates existing research in experimental research and theoretical research on different types of fibre materials, aiming to create Reference conditions for researchers in the same field. Finally, combined with research experience in related fields, new perspectives and proposals on FRC's research are proposed for research and application. This research paper is mainly focus on the different fibres (glass, cotton, steel). KEYWORDS:- GLASS FIBRE, COTTON FIBRE, STEEL FIBRE, TENSILE STRENGTH, COMPRESSIVE STRENGTH,

Psychological Effects of Music in Exercise and Sports Performance

Purpose: The general purpose of this study was to examine the psychological effects of music in exercise and sports performance.
 Methodology: The study adopted a desktop research methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library.
 Findings: The findings reveal that there exists a contextual and methodological gap relating to technology and traditional arts in modern sporting events. Preliminary empirical review revealed that music significantly influences psychological states during physical activity. It found that music with faster tempos and motivational lyrics enhanced arousal, mood, and performance outcomes such as endurance and coordination. Additionally, personalized music interventions tailored to individual preferences maximized the performance-enhancing effects of music. The study emphasized the importance of considering both psychological and physiological responses to music in designing effective interventions for optimizing performance outcomes and promoting exercise adherence. Overall, the findings highlighted the intricate relationship between music and exercise performance and suggested potential avenues for future research in this area.
 Unique Contribution to Theory, Practice and Policy: Theory of Arousal Regulation, Self-Determination Theory (SDT) and Attentional Focus may be used to anchor future studies on psychological effects of music in exercise and sports performance. The study provided comprehensive recommendations that contributed to theory, practice, and policy in the field. Through theoretical development, the study refined existing frameworks such as the Theory of Arousal Regulation and Self-Determination Theory, deepening our understanding of how music influences psychological states in athletic contexts. Practical guidelines were established to integrate music into athlete preparation routines, emphasizing personalized playlists and warm-up protocols to optimize performance outcomes. Policy implications highlighted the need to institutionalize music-based interventions in sports programs, promoting athlete well-being and enjoyment. Furthermore, the study identified future research priorities, evaluation frameworks, and public health initiatives to advance the integration of music into exercise and sports settings, fostering physical activity participation and overall health.

The Implications of Actovegin® in Sport: A Brief Review

Abstract Actovegin® (or Solcoseryl) is a deproteinized hemoderivative of calf’s blood, which contains more than 200 bioactive constituents. Screening and identification of biologically active molecule(s) is challenging due to the complexity of many constituents that may influence various cellular biochemical pathways and are found naturally in the body. Actovegin® comes in different forms including cream, gel, ointment, tablets, and injectable solution. Currently, according to section M2, Chemical and Physical Manipulation of the World Anti-Doping Code, intravenous injections of Actovegin® exceeding 100 ml is prohibited and further serial injections must be at least 12 hours apart. Although the performance-enhancing effects of Actovegin® are still anecdotal, the use of this drug has undoubtedly been widespread in sports for more than two decades. Existing findings provide promising results regarding the effect of Actovegin® in treating muscle injuries at the injected site. Further research exploring other forms of Actovegin ® (tablets, gel, cream) is encouraged to better understand the potential benefits of Actovegin® in applied sports settings.

Metabolic, cognitive and neuromuscular responses to different multidirectional agility-like sprint protocols in elite female soccer players – a randomised crossover study

PurposeResistance to fatigue is a key factor in injury prevention that needs to be considered in return-to-sport (RTS) scenarios, especially after severe knee ligament injuries. Fatigue should be induced under game-like conditions. The SpeedCourt (SC) is a movement platform for assessing multidirectional sprint performance, typical of game-sports, due to change-of-direction movements in response to a visual stimulus. Designing adequate fatigue protocols requires the suitable arrangement of several loading variables such as number of intervals, sprint distance or work/relief ratio (W:R). Therefore, this study analysed the acute fatigue effects of different SC protocols on metabolic load, cognitive function and neuromuscular performance.MethodsEighteen female soccer players (mean ± SD; age: 23.1 ± 4.6 years) of the 1st German Division participated in this randomised, crossover study. Using a random allocation sequence, players completed four volume-equated protocols differing in W:R and sprint distance per interval (P1:12 × 30 m, W:R = 1:2 s; P2:12 × 30 m, W:R = 1:3 s; P3:18 × 20 m, W:R = 1:2 s; P4:18 × 20 m, W:R = 1:3 s). Pre- and post-exercise, metabolic load was measured per blood lactate concentration (BLaC), cognitive function per reaction time (RT), and neuromuscular performance including multiple rebound jumps (MRJ height, primary outcome variable; Reactive Strength Index, RSI) and 5 m sprint times (SP5).ResultsRepeated-measures ANOVA revealed significant main time effects (p < .05) with improved performance post-exercise in RT (504 vs. 482 ms, d = 1.95), MRJ height (24.0 vs. 24.8 cm, d = 0.77), RSI (1.39 vs. 1.43, d = 0.52), and SP5 (1.19 vs. 1.17 s, d = 0.56). There was significant main time (p < .001) and time x protocol interaction effects in BLaC (p < .001). P1 induced higher BLaC values (4.52 ± 1.83 mmol/L) compared to P2 (3.79 ± 1.83 mmol/L; d = 0.74) and P4 (3.12 ± 1.83 mmol/L; d = 1.06), whereas P3 (4.23 ± 1.69 mmol/L) elicited higher BLaC values compared to P4 (d = 0.74).ConclusionAll protocols caused an improved cognitive function and neuromuscular performance. The former may be related to enhanced noradrenergic activation or exercise specificity which induced an improved stimulus processing. The latter may be explained by a possible post-activation performance enhancement effect on jump and sprint performance. A shorter relief duration in W:R as opposed to sprint distance per interval produced higher BLaC values. The protocols may serve as reference data for improved RTS decision-making in elite female soccer players.Trial registrationDeutsches Register Klinischer Studien (DRKS), No.: DRKS00033496, Registered 19. Februar 2024, Retrospectively Registered.

Enhancement of local anti-demagnetization ability of permanent magnet by selected area grain boundary diffusion toward high-speed motors

The working environment of permanent magnets in high-speed motors is harsh, because they are seriously affected by multi-physical fields such as temperature, stress, weak magnetic control field, etc., and irreversible demagnetization is easy to occur under the extreme working conditions. In this work, a model of high-speed Interior Permanent magnet Motor is established, the easy demagnetization area of the permanent magnet is simulated by electromagnetic and thermal simulations to determine, and its local anti-demagnetization optimization is performed. Dy/Tb co-infiltration is carried out in the easy demagnetization region of the permanent magnets, and the process of selective zone diffusion is analyzed based on the principle of selective zone grain boundary diffusion. Through microscopic observation and macroscopic magnetic performance test, the effect of local anti-demagnetization performance enhancement of the optimized permanent magnets is verified. The results show that the magnetic properties of the optimized permanent magnets are obviously improved after the optimization of the selected zones. The present approach is important for the follow-up less heavy-rare-earth research of permanent magnet and its application in high-speed motors.

Postactivation Performance Enhancement With Maximal Isometric Contraction on Power-Clean Performance Across Multiple Sets.

This study investigated the postactivation performance-enhancement effect of maximal voluntary isometric contraction (MVIC) at the starting position on power-clean performance over a series of contrast sets. Eighteen male (age: 31 [3.7]y, body mass: 76.8 [9.1]kg, height: 175.0 [5.2]cm) and 2 female (age: 27.5 [3.5]y, body mass: 53.3.8 [2.0]kg, height: 158.5 [4.9]cm) resistance-trained individuals performed a contrast postactivation performance-enhancement protocol (isometric contrast training condition [ISO]) consisting of 3 sets of 3 MVICs alternated with 3 power cleans, with an intracontrast rest period of 1minute. A control protocol consisted of 3 sets of 3 power cleans were performed in a separate session. Barbell velocity during the power clean was measured as an indicator of performance. A significant time effect was observed for both mean velocity(MV; P < .001) and peak velocity(PV; P = .008). Time × group (P = .415-.444) and group (P = .158-.210) effects showed no significant difference for either MV or PV. However, differences in MV and PV between the corresponding sets of ISO and control condition exceeded the minimum worthwhile change, showing a small to moderate effect (MV: d = 0.38-0.50, PV: d = 0.35-0.50) in favor of ISO. There was no significant difference in rating of perceived exertion between conditions (P = .385, d = 0.22). Power-clean performance was potentiated after 1minute of rest following 3 repetitions of MVIC across 3 sets. Furthermore, the ISO protocol did not result in greater perception of exertion. These results indicate that coaches may incorporate MVICs as the postactivation performance-enhancement stimulus during contrast training involving the power-clean exercise.

Evaluating the Efficacy of Eccentric Half-Squats for Post-Activation Performance Enhancement in Jump Ability in Male Jumpers

The purpose of the present study was to investigate effect of post-activation performance enhancement (PAPE) induced by the eccentric half-squat exercise on vertical jump performance in male jumpers. The jumping height, peak power, and work were measured and evaluated in twenty male jumpers (age: 21.2 ± 1.7 years, height: 191.1 ± 3.3 cm, body mass: 81.56 ± 7.3 kg) who participated in the national championship last year. Participants performed five eccentric half-squats at 85% of their one-repetition maximum (1 RM), with a knee angle below 90°, followed by immediate and 2 min delayed jump assessments using the Squat Jump (SJ) and Countermovement Jump (CMJ) tests. Results showed that this specific PAPE protocol did not significantly improve jump performance for the SJ (Height: ES = 0.613, p = 0.462, Work: ES = 0.124, p = 0.231, Power: ES = 0.382, p = 0.125) or CMJ (Height: ES = 0.523, p = 0.368, Work ecc: ES = 0.133, p = 0.505 (only main effect time p &lt; 0.05), Work con: ES = 0.114, p = 0.101, Power ecc: ES = 0.134, p = 0.177, Power con: ES = 0.182, p = 0.195, Leg stiffness: ES = 0.095, p = 0.358) tests. Factors such as stimulus specificity, rest intervals, muscle length, and the balance between potentiation and fatigue may explain these results. This study highlights the complexity of PAPE responses and suggests that a single set of eccentric squats with a short rest may not improve jump performance in male jumpers. Further research is required to optimize the interplay between conditioning stimuli and rest periods to maximize PAPE effects in athletic performance enhancement.

Pedal Quadrant-Specific Strength and Conditioning Considerations for Endurance Cyclists

ABSTRACT The performance-enhancing effects of strength training on cycling are well documented with findings from research, demonstrating resistance training with heavy loads conducted 2–3 times per week for at least 8 weeks can improve power output (maximal and submaximal), extend time to exhaustion, and reduce completion time for set distances, while not adding to the total body mass. Despite the evident benefits of strength training, there remains a lack of consensus regarding the most effective exercises to enhance endurance cycling. This uncertainty is evident when considering movement-specific exercises to enhance dynamic transfer to cycling. A range of lower-limb exercises involving hip, knee, and ankle flexion and extension seems to enhance cycling performance more so than static or single-joint exercises. These improvements may be attributed to enhanced coordination and improved pedaling technique. This study presents 5 strength training exercises designed to target cycling pedaling quadrants and replicate the unilateral opposing nature of cycling (simultaneous flexion and extension of the legs) to enhance transfer from weight room-based strength training to the bike. These exercises are presented in example programs alongside established “traditional” exercises that may be used to guide the development of strength training for cyclists.

Erratum. Effect of Mindful Sports Performance Enhancement in College Athletes for Reducing Sports-Caused Anxiety and Improving Self-Awareness: A Critically Appraised Topic

Erratum. Effect of Mindful Sports Performance Enhancement in College Athletes for Reducing Sports-Caused Anxiety and Improving Self-Awareness: A Critically Appraised Topic

Effect of Mindful Sport Performance Enhancement in College Athletes for Reducing Sports-Caused Anxiety and Improving Self-Awareness: A Critically Appraised Topic

Mindful Sport Performance Enhancement (MSPE) training is a relatively new concept, which focuses on helping athletes manage a variety of stressors experienced throughout a season, including performing well academically, staying fit, having a productive season in their sport, and maintaining a healthy social life. A need for a critical appraisal is needed to assess the effectiveness of the intervention. Two cohort studies and one randomized control trial were included in the study and assessed using STROBE and PEDro Scale. Key results show, all 3 studies identified participants experiencing benefits after MSPE with aspects of awareness, acceptance, and emotion regulation. Furthermore, student-athletes who attended either all the sessions or more sessions after the 6-week course showed greater satisfaction with mental and physical health. Overall, there is level “B” evidence to support effectiveness of MSPE for college athletes in reducing sport anxiety and improving their overall well-being.

Ammonia Inhalants: Use, Misuse, and Role in Sports Performance.

Ammonia inhalants, also known as smelling salts, are preparations of ammonia designed to treat fainting but more commonly used by athletes to boost awareness and arousal during competition. Despite their widespread use, the physiological and performance-enhancing effects of ammonia inhalants remain poorly understood. The aim of the present study was to review the current literature surrounding the benefits, risks, and physiological effects of ammonia inhalants. An extensive literature review of articles pertaining to ammonia inhalants was performed through MEDLINE and Google Scholar. The search terms "smelling salts," "ammonia inhalants," "strength," "performance," "head injury," and "concussion" were used. Clinical review. Level 4. The physiological response to acute ammonia inhalation includes cerebral vasodilation and heart rate elevation without change in blood pressure. The existing evidence demonstrates an ergogenic benefit to ammonia inhalant use only during repeated bouts of high-intensity exercise; in these subjects, ammonia inhalation was associated with increased power as measured by the Wingate anaerobic test. In contrast, there is no performance benefit to ammonia inhalants in a short burst of maximal effort despite elevated arousal and an associated perception of performance enhancement. Importantly, ammonia inhalants have no role in medical management of head injuries, as they have the potential to exacerbate an underlying brain injury due to the involuntary withdrawal reflex associated with ammonia inhalation. Furthermore, the signs and symptoms of a concussion or more threatening head injury may be masked by ammonia inhalation and lead to continued participation in competition, causing additional harm. Ammonia inhalants have no role in medical management of head injuries and have limited benefit with regards to sports performance. B.

Lived experiences of closeness to a person using Anabolic androgenic steroids a next of kin perspective

ABSTRACT Purpose Anabolic androgenic steroids (AAS) are used for their aesthetic and performance-enhancing effects and are associated with physical and psychological side effects. Behavioural changes/side effects as mood swings, aggressiveness, depression, potency problems, anxiety, and emotional coldness have been reported by next of kin to people using AAS. Methods This phenomenological study is based on the reflective lifeworld research approach. Interviews were conducted with twelve next of kin about their experiences of living close to persons using AAS. Results Next of kin to persons using AAS are particularly vulnerable because they experience little opportunity to influence their situation. Their given and safe context is lost, and their lives are circumscribed by feelings of insecurity, fear, powerlessness, and grief. Feelings of loneliness develop when their problems are not noticed by others and support is lacking from family and society. Conclusions Our research adds important knowledge on how the use of AAS affects next of kin. Understanding is required to approach the lifeworld of next of kin with flexibility and empathy in their difficulties and vulnerability. Healthcare professionals and other concerned professions need to be aware of next of kin existential needs to be able to meet and support them in their life situation.

Accommodating resistance is more effective than free weight resistance to induce post-activation performance enhancement in squat jump performance after a short rest interval

Background/objectivesPrior work regarding post-activation performance enhancement (PAPE) has shown that various resistance training methods and conditioning activities may induce a PAPE effect such as free weight resistance, accommodating resistance or isoinertial resistance. However, the accommodating resistance and other types of resistance have rarely been directly compared. Thus, the aim of this study was to compare the effects of two different conditioning activities (CA) - a trap bar deadlift with (FW + AR condition) or without (FW condition) accommodating resistance - on subsequent squat jump (SJ) performance after a short rest interval of 90s. MethodsThe study had a cross-over design and fifteen strength trained males (mean age: 22.9 ± 2.1 years; mean relative strength level 2.01 ± 0.27 kg/body mass) participated in one familiarization, two experimental and one control session (CNTR condition). Two CAs were implemented throughout the study - a single set of 3 repetitions of a trap bar deadlift at 80 % of 1RM using solely free weight resistance or with the addition of approximately 15 % of 1RM elastic band tension. The SJ measurements were performed at the baseline and 90s after CAs. ResultsThe FW + AR condition significantly improved subsequent SJ performance (p < 0.05, effect size 0.34) whereas the FW and CNTR conditions were found to be ineffective to acutely enhance performance. ConclusionsOur results suggest that the addition of accommodating resistance is superior to free weight resistance in order to acutely improve jump performance after a 90s rest interval. To observe the performance enhancement effect with solely free weight resistance it should be considered to introduce alteration in loading strategies or possibly lengthening the rest interval.