Corrigendum: Enjoyment as a predictor of exercise habit, intention to continue exercising, and exercise frequency: the intensity traits discrepancy moderation role.

[This corrects the article DOI: 10.3389/fpsyg.2022.780059.].

Feasibility and Usefulness of Repetitions-In-Reserve Scales for Selecting Exercise Intensity: A Scoping Review.

The intensity of resistance training (RT) exercise is an important consideration for determining relevant health and performance-related outcomes. Yet, current objective exercise intensity measures present concerns in terms of viability or cost. In response to these concerns, repetition-in-reserve (RIR) scales may represent an adequate method of measuring and regulating intensity. However, no recent review has focused on how RIR scales have been used for this purpose in prior research. We prepared the present scoping review to analyze the feasibility and usefulness of RIR scales in selecting RT intensity. We conducted a systematic search in PubMed, SPORTDiscus, PsycINFO, and ClinicalTrials.gov databases (last search date April 2023) for experimental and non-experimental studies that utilized an RIR scale to measure proximity to failure in RT activities with apparently healthy individuals of any age. We qualitatively analyzed 31 studies (N = 855 mostly male adult participants) published between 2012-2023. RIR scales appeared to be contextually feasible and useful in prescribing and adjusting RT intensity. The most common trend in this research was to prescribe a target RIR and adjust the exercise load for a desired proximity to muscle failure. Additionally, when measuring proximity to failure as an outcome of interest, the literature suggests that the RIR prediction should be made close to task failure to increase its accuracy. Future research should further explore the impact of sex, RT experience, exercise selection, and muscle conditioning on the overall RIR approach.

Validation of the Portuguese Version of the Perceived Physical Literacy Instrument.

BACKGROUND: The Perceived Physical Literacy Instrument (PPLI) has been the most adopted physical literacy instrument designed for adults to date, having been already translated to 5 languages. Still, despite its popularity, there is limited evidence of its psychometric properties. The aim of this study was to translate and adapt cross-culturally the PPLI to the Portuguese language and to analyze the psychometric properties of the Portuguese version in a sample of Portuguese-speaking adults. METHODS: The study sample was composed of 434 participants (70% females) with a median age of 25 (18-39) years. Confirmatory factor analysis was used to assess psychometric properties of the scale. In addition, instrument assumptions between sexes through invariance testing were examined. Finally, concurrent validity, test-retest reliability, and test-retest agreement analyses were performed to gather additional evidence. RESULTS: The results of the present study generally supported the measurement model. The 9-item, 3-factor model presented a good fit to the data and adequate construct validity (χ2 = 82.859 [24], P < .001, comparative-fit index = .948, Tucker-Lewis index = .922, standardized root mean square residual = .049, root mean square error of approximation = .075). In addition, the scale presented concurrent validity. Some issues arose with measurement invariance and overtime consistency. CONCLUSIONS: Considering the lack of validated instruments, we suggest a fair use of Portuguese version of PPLI to access physical literacy in adults. This study contributes to the validation of the PPLI by providing evidence of its psychometric properties in the Portuguese-speaking adult population and facilitates comparative analysis with previous and future studies utilizing the PPLI instrument.

Analysis of the Effect of Different Physical Exercise Protocols on Depression in Adults: Systematic Review and Meta-analysis of Randomized Controlled Trials.

CONTEXT: Physical exercise (PE) is an effective treatment for depression, alone or as an adjunct. OBJECTIVE: There is a lack of indicators regarding the frequency, intensity, duration, and type of physical exercise (PE). This study aims to synthesize and analyze the dose-effect of different PE protocols in adult subjects in the treatment of depression, based on the analysis of randomized controlled trials (RCTs). DATA SOURCES: The search was conducted using Web of Science, PubMed, and Cochrane Library electronic databases. STUDY SELECTION: Studies with an exercise-based intervention published by December 31, 2021 were identified. RCTs and meta-analyses involving adults with depression were also included; 10 studies were selected, including a total of 956 subjects. STUDY DESIGN: Systematic review and meta-analysis. LEVEL OF EVIDENCE: Level 1. RESULTS: Effect sizes were summarized using standardized mean differences (95% confidence interval) by effected randomized models. The results reinforce that exercise appears to be beneficial in improving depression among adults aged 18 to 65 years. Interventions lasting above 150 minutes per week of moderate intensity and group interventions seem to have a more significant effect on reducing depression. Studies have revealed that aerobic exercise, compared with resistance or flexibility, has a more positive effect on depression. CONCLUSION: PE can be a way to reduce depression and can be used as a possible adjunctive tool for pharmacological and/or alternative treatments. Considering the findings of this study, it is important that health professionals (eg, exercise physiologists, physicians, nurses, psychologists) promote the practice of PE as a complementary alternative and act early to prevent the worsening of depression. PROSPERO REGISTRATION NUMBER: CRD42020188909.

From data to action: a scoping review of wearable technologies and biomechanical assessments informing injury prevention strategies in sport.

BACKGROUND: The purpose of this scoping review was to evaluate the current use of technologies in sports settings for training adaptation and injury prevention. The review aimed to map the existing literature, identify key concepts and themes, and highlight gaps in research, thus offering guidance for future studies. METHODS: This study followed the guidelines of the PRISMA extension for scoping reviews and a search in four major databases was conducted. RESULTS: A total of 21 studies were included. The findings highlighted the widespread use of various technologies, including wearable devices and force plates, to monitor athletes' performance and inform evidence-based decision-making in training and injury prevention. Variables such as Player Load, changes of direction, and acute chronic workload ratio were identified as key metrics in injury prediction. CONCLUSIONS: This review uncovers a dynamic field of research in athlete injury prevention, emphasizing the extensive use of varied technologies. A key finding is the pivotal role of Player Load data, which offers nuanced insights for customizing training loads according to sport-specific demands, player positions, and the physical requirements of various activities. Additionally, the review sheds light on the utility of tools like force plates in assessing fatigue, aiding recovery, and steering injury rehabilitation, particularly in sports prone to knee and ankle injuries. These insights not only enhance our understanding of injury prevention but also provide a strategic direction for future research, aiming to boost athlete safety, performance, and career longevity.

Assessing affective valence and activation in resistance training with the feeling scale and the felt arousal scale: A systematic review.

Evidence suggests affective responses to exercise can influence exercise adherence. However, there is a limited understanding of how and when to measure core affect in resistance training. As such, the objective of this systematic review was to analyze how the Feeling Scale and/or the Felt Arousal Scale have been used in resistance training to assess core affect. Focus was given to the contextual feasibility, timing, and frequency of assessment. A search in PubMed, SPORTDiscus, and PsycINFO databases was conducted (last search date July, 2022) with the purpose of including experimental and non-experimental studies, utilizing the Feeling Scale and/or the Felt Arousal Scale in resistance training, and focused on apparently healthy individuals of any age. Twenty-seven studies (N = 718 participants) published between 2009-2022 were qualitatively analyzed. Both scales appeared to be able to detect core affect within a wide array of intensities, ages, and equipment. As for the timing and frequency of measurement, no apparent standardization was evident. The use of the Feeling Scale, the Felt Arousal Scale, or both, to measure core affect appears to be feasible in resistance training practices. However, a lack of methodological background raises concerns regarding the quality of previous studies' assessments and comparisons of results across studies.

Exploring the impact of individualized pleasure-oriented exercise sessions in a health club setting: Protocol for a randomized controlled trial.

Research on the relationship between exercise-induced affect and exercise or physical activity behavior has gained momentum in recent years, yielding several observational and longitudinal studies. However, experimental tests demonstrating a causal role of affective responses on exercise adherence are lacking. Given the need to devise exercise prescriptions that can facilitate adherence and promote regular physical activity, a Randomized Controlled Trial targeting individual pleasurable responses in a health-club setting will be conducted. The experimental protocol will compare two individualized evaluation, prescription, and supervision methods, adjusted for intensity, with the aim to explore their impact on behavioral, affective, and motivational outcomes. The planned study will be a pragmatic randomized, single-blinded, controlled superiority trial with two parallel groups and an allocation ratio of 1:1. Apparently healthy volunteer participants (N = 46) between 18 and 45 years old, who are not regularly active, will be randomly allocated to a control or experimental group. The control group will follow a general American College of Sports Medicine exercise prescription; the experimental group will follow the same prescription but with enhancements aimed at promoting pleasure: (1) individualization based on individual differences in preference for and tolerance of exercise intensity; (2) self-regulation of intensity; and (3) repeated assessments of core affect. The primary outcome will be post-intervention exercise-session attendance. Affective and motivational variables will be examined as secondary outcomes. The results are expected to advance exercise prescriptions by promoting affective regulation, thus helping to improve exercise adherence and related outcomes. TRIAL REGISTRATION: ClinicalTrials.gov; ID: NCT05416593.

Affective responses to stretching exercises: Exploring the timing of assessments.

Affective responses during exercise have been identified as a predictor of exercise adherence. However, research has been mostly limited to aerobic and resistance exercise. Considering that stretching activities are also an important component of physical fitness, this quasi-experimental study was designed to: 1) compare affective responses during and immediately after stretching exercises in apparently healthy adults, and 2) assess the consistency and repeatability of affect ratings obtained one week apart. For this purpose, we analyzed the Feeling Scale (FS) and Felt Arousal Scale (FAS) ratings using Time (during and after stretching) x Intensity (light, moderate, vigorous) x Stretched Muscle Group (quadriceps, hamstrings, glutes, latissimus dorsi, triceps) with repeated measures analysis of variance (ANCOVA) in 34 participants (21 males; aged 32.8 ± 8.6 years). The repeatability of FS and FAS ratings was assessed using two-way random-effects models, Intraclass Correlation Coefficients (ICC), and Bland-Altman plots. FS scores were higher following the stretching exercises, whereas FAS scores were lower, particularly in the vigorous intensity. In general, the inter-day repeatability for FS and FAS measurements was good across muscle groups. ICC tended to be higher at vigorous intensities. Ratings of core affect can be collected during static passive stretches using the FAS and FAS in ecologically valid settings. These results suggest that an adequate assessment of core affective responses to stretching activities should be performed during the exercises.

Using Psychometric Testing Procedures for Scale Validity, Reliability, and Invariance Analysis: The PRETIE-Q Portuguese Version.

This study investigated the psychometric nature of preference for and tolerance of exercise intensity in physical activity. It initially re-examined the Preference for and Tolerance of the Intensity of Exercise Questionnaire (PRETIE-Q) among Portuguese exercisers, looking at its applicability to different exercise activities and exercise experiences. Then, to investigate the applicability of the measure in different groups, its invariance was examined. The sample consisted of 1117 participants (528 male, 589 female) aged 18-81 years old (Mage = 36.81, SD = 11.89). All participants reported at baseline that they were exercising, on average, 3.93 days (SD = 1.36) per week. The exploratory structural equation modeling (ESEM) displayed the best fit. The ESEM did show invariance when tested for multigroup analysis. The conclusion of this research is that the ESEM demonstrated the best fit, displaying invariance in multigroup analysis. Furthermore, when assessing preference and tolerance in various exercise modalities, the PRETIE-Q should be primarily used as a multidimensional instrument due to the differential recognition of preference and tolerance in seemingly similar physical activity circumstances, highlighting the importance of employing context-verified measures to evaluate exercise-intensity preference and tolerance based on sample characteristics or real-time context.

Testing Assumptions of the Physical Activity Adoption and Maintenance Model: A Longitudinal Perspective of the Relationships Between Intentions and Habits on Exercise Adherence.

In this study, we aimed to examine empirically the Physical Activity Adoption and Maintenance model (PAAM). We collected data on these variables at baseline (T0) and 6-months later (T1). We recruited 119 participants (42 male, 77 female) aged 18-81 years old (Mage = 44.89, SD = 12.95). who reported, at baseline, that they exercised an average of 3.76 days per week (SD = 1.33) in training periods lasting 15-60 minutes (M = 38.69; SD = 23.28). We conducted hierarchical multiple regression analysis to test the association between each determinant (intentions, habits, and frequency) and future exercise adherence. We tested four models by entering blocks of predictors according to PAAM assumptions. The variance change (R2) between the first and fourth models (ΔR2 = .391) was statistically significant, showing that the fourth model accounted for 51.2% of variance for future exercise adherence, F (6, 112) = 21.631, p < .001, R2 = .73, adjusted R2 = .512. Exercise intention at T1 maintained its significant association (p = .021) with exercise frequency at T1 in all tested models. Exercise frequency at T0 was the most significant predictor (p < .01) of future exercise adherence, with past experience the second most significant predictor (p = .013). Interestingly, exercise habits at T1 and T0 did not predict exercise frequency at T1 in the fourth model. Among the variables we studied, having constantly high exercise intentions and high regular exercise frequency are significantly associated with maintaining or increasing regular future exercise behavior.

Assessing Affective Valence and Activation in Stretching Activities with the Feeling Scale and the Felt Arousal Scale: A Systematic Review.

Affective responses have been considered key determinants for exercise adherence, but research on affective responses to stretching activities is scarce. Given the role of these responses in exercise adherence, our aim in this review was to explore (a) the utility and feasibility of core affect in stretching-related activities as measured by the Feeling Scale (FS) and/or the Felt Arousal Scale (FAS); (b) the timing of administering these scales; and (c) the scales' applicability and interpretability in this context. Inclusion criteria for studies in this review were experimental and non-experimental studies written in English that based affect assessment on the FS and/or FAS and that applied these scales to participants engaged in physical activity, individually or in groups. We also considered studies that focused on stretching activities that were either isolated or components of a class/activity and studies that used healthy participants of any age. Exclusion criteria were populations with mental health problems, cancer, diabetes, hypertension, cardiovascular disease, or diseases likely to alter pain perception or be associated with chronic pain, instrument validation studies, gray literature, and systematic reviews. We searched PubMed, SPORTDiscus and PsycINFO databases, and we added studies retrieved manually from reference sections while following PRISMA guidelines. We used the Effective Public Health Practice Project tool for judging methodological quality of research articles. Our final analyses were based on 12 empirical studies published between 2003 and 2021with a total of 718 participants. Both scales were found to be useful and feasible in the most usual places for exercise, but core affect results cannot be properly interpreted due to variability of study protocols and the absence of guidelines for adequate baseline assessment. Most studies recorded affect responses pre-session, during session, and post-session. We observed no standardized timing or frequency of assessment, and there was high heterogeneity among stretching protocols. Currently, research in core affect assessment of stretching-related activities lacks sufficient methodological quality to draw generalizable conclusions.

How Does the Level of Physical Activity Influence Eating Behavior? A Self-Determination Theory Approach.

Physical activity and diet are two predominant determinants of population health status that may influence each other. Physical activity has been identified as a behavior that may lead to a healthier diet and regulates eating behaviors. This research aimed to investigate how the level of physical activity is associated with the motivation related to eating behaviors and, consequently, the eating style individuals have on a daily basis. This was a cross-sectional study in which participants completed an online questionnaire that assessed the following variables: the level of physical activity, the motivation toward eating behavior, and the type of eating behavior. In total, 440 individuals (180 men and 260 women) who regularly exercised in gyms and fitness centers aged between 19 and 64 years (M = 33.84; SD = 10.09) took part in the study. The data were collected following the Declaration of Helsinki and with the approval of the Ethics Committee of the Polytechnic of Leiria. For the statistical analysis, mean and standard deviations were first calculated, as well as bivariate correlations between all the variables of interest. Then, structural equation model analyses were performed considering the levels of physical activity as the independent variable, motivations toward eating behavior as the mediators, and eating styles as the dependent variables. It was concluded that a greater level of physical activity leads to a more self-determined type of eating regulation, which in turn results in less constricted eating behaviors that are influenced by external factors and emotional factors.

Using passive Wi-Fi for community crowd sensing during the COVID-19 pandemic.

Sensing passersby and detecting crowded locations is a growing area of research and development in the last decades. The COVID-19 pandemic compelled authorities and public and private institutions to monitor access and occupancy of crowded spaces. This work addresses the detection of crowds in points of interest (POI) by using a territory grid analysis categorizing POIs by the services available in each location and comparing data gathered from a community passive Wi-Fi infrastructure against mobile cellular tower association data from telecom companies. In Madeira islands (Portugal), we used data from the telecom provider NOS for the timespan of 4 months as ground truth and found a strong correlation with sparse passive Wi-Fi. An official regional mobile application shows the occupancy data to end-users based on the territory categorization and the passive Wi-Fi infrastructure in POIs. Occupancy data shows historical hourly trends of each location, and the real-time occupation, helping visitors and locals plan their commutes better to avoid crowded spaces.

The stress granule protein G3BP1 alleviates spinocerebellar ataxia-associated deficits.

Polyglutamine diseases are a group of neurodegenerative disorders caused by an abnormal expansion of CAG repeat tracts in the codifying regions of nine, otherwise unrelated, genes. While the protein products of these genes are suggested to play diverse cellular roles, the pathogenic mutant proteins bearing an expanded polyglutamine sequence share a tendency to self-assemble, aggregate and engage in abnormal molecular interactions. Understanding the shared paths that link polyglutamine protein expansion to the nervous system dysfunction and the degeneration that takes place in these disorders is instrumental to the identification of targets for therapeutic intervention. Among polyglutamine diseases, spinocerebellar ataxias (SCAs) share many common aspects, including the fact that they involve dysfunction of the cerebellum, resulting in ataxia. Our work aimed at exploring a putative new therapeutic target for the two forms of SCA with higher worldwide prevalence, SCA type 2 (SCA2) and type 3 (SCA3), which are caused by expanded forms of ataxin-2 (ATXN2) and ataxin-3 (ATXN3), respectively. The pathophysiology of polyglutamine diseases has been described to involve an inability to properly respond to cell stress. We evaluated the ability of GTPase-activating protein-binding protein 1 (G3BP1), an RNA-binding protein involved in RNA metabolism regulation and stress responses, to counteract SCA2 and SCA3 pathology, using both in vitro and in vivo disease models. Our results indicate that G3BP1 overexpression in cell models leads to a reduction of ATXN2 and ATXN3 aggregation, associated with a decrease in protein expression. This protective effect of G3BP1 against polyglutamine protein aggregation was reinforced by the fact that silencing G3bp1 in the mouse brain increases human expanded ATXN2 and ATXN3 aggregation. Moreover, a decrease of G3BP1 levels was detected in cells derived from patients with SCA2 and SCA3, suggesting that G3BP1 function is compromised in the context of these diseases. In lentiviral mouse models of SCA2 and SCA3, G3BP1 overexpression not only decreased protein aggregation but also contributed to the preservation of neuronal cells. Finally, in an SCA3 transgenic mouse model with a severe ataxic phenotype, G3BP1 lentiviral delivery to the cerebellum led to amelioration of several motor behavioural deficits. Overall, our results indicate that a decrease in G3BP1 levels may be a contributing factor to SCA2 and SCA3 pathophysiology, and that administration of this protein through viral vector-mediated delivery may constitute a putative approach to therapy for these diseases, and possibly other polyglutamine disorders.

Corrigendum: Impact of victory and defeat on the perceived stress and autonomic regulation of professional eSports athletes.

[This corrects the article DOI: 10.3389/fpsyg.2022.987149.].

Clinical applications of exercise in Parkinson's disease: what we need to know?

INTRODUCTION: Exploring the potential of exercise in the rehabilitation process of patients with Parkinson's (PD) may be an interesting treatment perspective. Exercise-induced responses derived from neurotrophic elements appear to ameliorate the decline in neurodegeneration. Despite this understanding, the literature needs to be updated. AREAS COVERED: Our review focuses on: a) the key mechanisms of exercise on PD, highlighting mainly the responses related to neuroplasticity; b) the effects induced by different traditional types of exercise, also highlighting the effects of complementary therapies related to movement; c) the volume of exercise required to support efficient results are explored in the context of PD. Additionally, the proposition of new clinical application strategies in the context of PD will also be determined. EXPERT OPINION: It is suggested that different intensities of aerobic exercise be explored for the treatment of PD. The results associated with high intensity seem promising for performance, physiological and clinical parameters, such as BDNF production and cognition. On the other hand, the diversification of tasks and repetition of motor gestures appear as consistent arguments to exercise prescription. Finally, for future investigations, the neuromodulation strategy in association with aerobic exercise appears as a potential inducer of benefits on gait and cognitive function.

Impact of victory and defeat on the perceived stress and autonomic regulation of professional eSports athletes.

Competitive sports involve physiological, technical and psychological skills, which influence directly on individuals' performance. This study aims to investigate the levels of perceived stress and Heart Rate Variability (HRV) before and after matches with victory and defeat in professional eSports athletes. Our hypothesis was that the winners would have better autonomic and stress responses after match, thus corroborating the literature on neurocardiac connections. Fifty male eSport players were selected players from 10 different Brazilian teams. The experiment was carried out in 2 sessions. Firstly, after signing the informed consent form, 24 h before the game, anthropometric, physical activity levels and time of expertise data were recorded only for sample characterization and the players were familiarized with the perceived stress scale-10 (PSS-10) and the HRV measurements. Secondly, players performed the PSS-10 and HRV recording at rest by 10 min 60 and 30 min before the game (i.e., baseline time) and 10 min after the end of the game. Overall, concerning PSS-10 our findings show that VG had significant reduced scores in post-game time compared to baseline (BL) and pre-game times, while DG had significant increased scores in post-game time compared to BL and pre-game times. Regarding HRV, our results demonstrate that VG had significant increase in RR, SDNN, rMSSD, pNN50 and HF, and significant decrease in LF and LF/HF, while DG had a significant decrease in RR, SDNN, rMSSD and HF, and significant increase in LF and LF/HF. It was observed that VG had better HRV responses (greater parasympathetic activation) as well as lower levels of perceived stress, while DG had worst HRV responses (greater sympathetic activation) and higher levels of perceived stress.

Understanding the Associations across Fibromyalgia-Related Fatigue, Depression, Anxiety, Self-Esteem Satisfaction with Life and Physical Activity in Portuguese and Brazilian Patients: A Structural Equation Modeling Analysis.

Background and Objectives: Fibromyalgia are heterogeneous and differ from patient to patient; however, the most reported are general myalgia and at specific points associated with fatigue and certain psychological adversities. Physical activity can mitigate the effects of the symptoms. However, the associations between fibromyalgia-related fatigue, self-esteem, anxiety, depression, satisfaction with life and physical activity are unclear. Therefore, the aim of the present study was to understand the associations between these symptoms and whether there are differences between these associations across two distinct cultures. Materials and Methods: A total of 473 women aged between 28 and 75 years (M = 49.27; SD ± 8.28) completed five questionnaires about fibromyalgia-related fatigue, physical activity, anxiety, depression, self-esteem, and satisfaction with life. Results: Fibromyalgia-related fatigue was positively associated with depression and anxiety, depression and anxiety were negatively associated with self-esteem, self-esteem was positively associated with satisfaction with life, satisfaction with life was positively associated with physical activity and there were no differences in terms of the perceptions and associations of these variables between Portuguese and Brazilian patients. Conclusions: Our results showed the significant role of associations between these variables and a similarity in the perception and relationship of the variables between the two cultures.

Set to fail: Affective dynamics in a resistance training program designed to reach muscle concentric failure.

Grounded in hedonic assumptions, evidence suggests that people tend to engage in activities they consider pleasurable and enjoyable, while trying to avoid pain and displeasure. This suggests that the dynamic between positive and negative affect can influence current behavior and the intentions to continue performing. Regarding resistance training (RT), research focusing on how to promote a better affective response is still scarce and much needed. Given existing limitations and theoretical suggestions, a RT program was developed and applied to recreational exercisers in a quasi-experimental design aiming to (1) explore the affective response dynamic through an assessment after the last set of each exercise; and (2) analyze possible differences of preference and tolerance profiles in affective variables (core affect and enjoyment). For that purpose, 43 participants (21 male and 22 female; Mage  = 34.69 ± 6.71 years; Mexperience  = 8.32 ± 4.54 years; MBMI  = 24.26 ± 2.64 kg/m2 ) accepted to participate in this study. Descriptive statistics, correlational, and group comparisons analyses were performed to provide evidence for proposed objectives. The present study showed that measures of affective valence/arousal applied immediately after a set represents a feasible and ecologically valid approach to tap core affect. Results presented evidence that recreationally trained exercisers in a common RT program would need a minimum of one measurement to assess the affective response. However, additional assessments could refine the understanding of exercise pleasurable experience. Results also suggest that exercisers with distinct profiles of preference/tolerance depicted differentiated patterns for the affective response, possibly justifying a distinct approach when promoting affective regulation.

Exploring the Relationship between Fibromyalgia-Related Fatigue, Physical Activity, and Quality of Life.

The symptoms of fibromyalgia are varied, including general muscle pain and pain at specific points (also called tender points), excessive fatigue, anxiety, depression, and some psychological problems that can have a negative impact on quality of life. Physical activity is a widely used option by health professionals to alleviate the effects of this syndrome. However, there is no clear information on the possible mediating role of physical activity in the relationship between fibromyalgia-related fatigue and quality of life. Therefore, this study aims to evaluate the relationship between fibromyalgia-related fatigue and quality of life, and to investigate the mediating role of physical activity in patients with this syndrome. METHODS: In a cross-sectional study, 237 Portuguese women aged 28 to 75 years (M = 49.12; SD ± 8.87) and 117 Brazilian women aged 20 to 69 years (M = 46.72; SD ± 8.38) were recruited to participate in this study. These patients completed three valid and reliable questionnaires related to the assessment of fibromyalgia-related fatigue (MDF-Fibro-17), physical activity (IPAQ), and quality of life (SF-36). RESULTS: Both samples had scores above the midpoint for all dimensions of fibromyalgia-related fatigue and scores below the midpoint for quality of life. Physical activity had no mediating effect in either sample, as the total indirect effect was not significant. CONCLUSIONS: Physical activity does not mediate the relationship between fatigue and quality of life. However, the results also show that the fatigue dimensions associated with fibromyalgia had a negative and significant association with physical and mental health indicators in both samples. Thus, patients with FM with higher scores on fatigue-related symptoms might suffer more from physical and mental health, both of which are related to quality of life.