Quantifying the Placebo Effect in Psychological Outcomes of Exercise Training: A Meta-Analysis of Randomized Trials

Selecting an appropriate control group for studying the effects of exercise on cognitive performance

Differences in expectations between experimental and control groups can influence the outcomes of exercise interventions, emphasizing the need to match expectations across study groups. This online study examined whether the expectations to improve the performance of different cognitive tasks differ between various activities commonly used in research on the effects of exercise and cognitive function. Two hundred and five middle-aged adults performed two reaction-time tasks and one memory task. They were then asked to rate, on a 1-5 Likert scale, their expectations to improve performance in those tasks should they engage in six types of activities for three months: brisk walking, resistance exercise, stretching and balance exercises, watching videos with lectures on art, history, and science, a program of relaxation techniques, and yoga/tai chi/meditation. Results revealed that the highest expectations for improvement were associated with relaxation techniques and yoga/tai chi/meditation. Some activities, such as brisk walking and stretch and balance exercises, shared similar expectations. Previous knowledge of the possible beneficial effects of exercise on cognitive performance also led to higher expectations. To establish causal relationships, researchers should strive to use activities that share similar expectations to improve performance for the experimental and control groups. The findings of this study provide such activity pairs. Finally, researchers should also try to match participants with and without prior knowledge of the benefits of exercise to cognitive function between experimental and control groups.

The Nexus of Training Duration, Body Image, Nutritional Practices, and Mental Health: Insights from a Strength Training Cohort

This study investigated the intricate relationship between strength training and its effects on body image, psychological health, and nutritional habits. By examining 605 participants, divided into two groups based on training frequency, the research aimed to discern how varying intensities of training influenced different wellness facets. The investigation employed a comprehensive survey, gathering demographic data, training specifics, dietary patterns, and psychological characteristics, utilizing statistical tools for analysis. Results unveiled significant differences in dietary habits and psychological profiles between groups with higher and lower training frequencies. The group with more frequent training displayed less favourable health outcomes and suboptimal dietary habits, challenging the prevailing notion that increased training frequency leads to better health. The study emphasized the necessity of a balanced approach to physical training, highlighting the need for personalized strategies that encompass both physical and mental health considerations. The findings exposed the complexities of training regimens and their broader implications on individual health, suggesting that enhanced training frequency alone does not assure improved health outcomes. This research significantly contributed to the domain by providing insights into how the frequency of strength training could differentially affect health and well-being, offering valuable guidelines for fitness professionals and healthcare providers.

Want to be fit? Start with your mind! The role of the placebo effect in physical fitness in children: a preliminary systematic review and meta-analysis

Physical activity is crucial to prevent and reduce excess body mass. The placebo effect can influence the outcomes of fitness-related interventions; however, this topic has not yet been extensively investigated in children. Summarising the data on placebo effects in fitness-related interventions is essential to understand this problem better. A systematic review of PubMed, Cochrane, PsycINFO, PsycARTICLES, TripDatabase and Embase was carried out. A meta-analysis of the results of studies with comparable research plans was performed. There were significant differences, favouring the placebo intervention. At the final follow-up, the children in placebo groups had higher maximal heart rates, shorter recovery times, longer ergometry phases, running time and lower peak and average perceived exertion than the control. The placebo effect is present in fitness-related parameters in children, regardless of the Body Mass Index status. It is crucial, as for youth with excess body mass, it is difficult to be active, especially to show appropriate levels of motivation and involvement. Importantly, the benefits of the placebo were the strongest in the motivation/ engagement-related parameters and self-assessed exertion. Notably, the nocebo effect was not observed, which is advantageous when considering placebo interventions in practice.

Exercise as Treatment for "Stress-Related" Mental Disorders

The beneficial impact of physical activity on preventing and treating mental disorders has captured growing (research) interest. This article aims to provide a concise overview of essential evidence regarding the effectiveness and underlying mechanisms of physical activity for individuals with mental disorders clustered as "stress-related" conditions. Empirical findings (e.g., longitudinalprospective studies, interventional randomized-controlled-trials, reviews, meta-analyses) regarding the effects of physical activity in the prevention and treatment of stress-related mental disorders are summarized. Furthermore, potential mechanisms underlying these effects are discussed, and recommendations regarding the use of physical activity are outlined. The majority of studies indicate good efficacy of physical activity in prospectively lowering the risk for the incidence of subsequent stress-related mental disorders as well as in the treatment of manifest disorders. Most evidence targets unipolar depressive disorder and, secondly, anxiety disorders. Research regarding posttraumatic stress disorder, obsessive-compulsive disorders, and somatoform disorders is promising but scarce. Physical activity seems to be useful as a stand-alone-treatment as well as in combination with other psychotherapeutic or pharmacological treatments. Multiple intertwined physiological, psychological, and social mechanisms are assumed to mediate the beneficial effects. Recommendations regarding physical activity can orientate on official guidelines but should consider the individual needs and circumstances of each subject. In summary, physical activity seems to be effective in the prevention and treatment of stressrelated mental disorders and, therefore, should be fostered in healthcare-settings. Future studies are needed to clarify partly inconsistent patterns of results and to close research gaps, e.g., concerning somatoform disorders.

Endocannabinoid and psychological responses to acute resistance exercise in trained and untrained adults

INTRODUCTION

This study examined the effects of acute resistance exercise on circulating endocannabinoid (eCB) and mood responses in trained and untrained healthy adults.

METHODS

Thirty-two healthy adults (22.1 ± 2.9 years) were recruited from trained (reporting resistance exercise at least twice per week for ≥ previous three months) and untrained (performing no resistance exercise for ≥ previous three months) groups. Participants (13 male, 19 female) completed three sets of resistance exercise (16 repetitions at 50% 1-repetition max, 12 repetitions at 70% 1-repetition max, 8 repetitions at 80% 1-repetition max). Resistance machines targeted the legs, chest, back, and abdominal muscles. Mood states, affect, and circulating eCB concentrations were evaluated before and after resistance exercise.

RESULTS

There were significant decreases in AEA, PEA, and OEA levels following acute resistance exercise (p <0.05; ds = -0.39, -0.48, -0.65, respectively), with no significant group differences or group by time interactions. 2-AG did not change significantly. Positive affect increased significantly following resistance exercise (p = 0.009), while negative affect decreased (p <0.001). Depressive symptoms, anger, confusion, and total mood disturbance decreased significantly (p <0.05), while vigor increased significantly following resistance exercise (p = 0.005). There were no significant group differences or group by time interactions for any psychological outcomes.

CONCLUSION

These results indicate that acute resistance exercise may reduce eCB and related lipid concentrations, which is opposite to the increase in lipids typically observed with acute aerobic exercise. Furthermore, psychological improvements occur after resistance exercise regardless of decreases in eCBs, supporting the notion that psychological changes with exercise likely occur through a wide variety of biological and environmental mechanisms.

The Interplay Between Expected Psychological Responses to Exercise and Physical Activity in Analogue Generalized Anxiety Disorder: a Cross-sectional Study

BACKGROUND

Expectations for psychological responses to exercise are not well characterized, particularly in people at risk for anxiety-related illnesses. Given the substantial evidence for salutary effects of exercise on anxiety symptoms and emerging recognition for expectations as a critical mechanism of placebo/nocebo effects, this study explored the interplay between expectations and physical activity in young adults with and without analogue generalized anxiety disorder.

METHODS

Participants (N=470, 23.2±4.8 years, 63% female) completed a physical activity and mood survey, including a 7-day physical activity recall questionnaire, and a 20-item questionnaire designed to measure positive and negative expectations for psychological and perceptual responses to exercise, particularly expectations for symptoms in the generalized anxiety disorder symptom profile. Analogue generalized anxiety disorder status was determined using the Generalized Anxiety Disorder subscale of the Psychiatric Diagnostic Screening Questionnaire.

RESULTS

For select outcomes, expected exercise-induced changes significantly differed according to analogue generalized anxiety disorder (whole-body pain, sleep quality, psychological well-being, stress, relaxation) and active versus inactive (anxious mood, depressed mood, concentration, physical function, psychological well-being, relaxation) status. However, these findings did not survive corrections for multiple comparisons and the magnitude of these differences was small, approximating 0.25 standard deviations. Expectations for anxious (Spearman's ρ=-0.14, p≤0.002) and depressed mood (ρ=-0.15, p≤0.002), and psychological well-being (ρ=0.15, p≤0.001) were significantly associated with higher physical activity levels. Exercise expectations for anxious mood explained a significant, but small (+1.5%, p≤0.03), amount of variance in physical activity.

CONCLUSIONS

Expectations for exercise-induced improvements did not significantly differ between young adults based on analogue generalized anxiety disorder or physical activity status.

An umbrella review of randomized control trials on the effects of physical exercise on cognition

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan. Here we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias and large variation in combinations of pre-processing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows small exercise-related benefits (d = 0.22, 95% confidence interval 0.16 to 0.28) that became substantially smaller after accounting for key moderators (that is, active control and baseline differences; d = 0.13, 95% confidence interval 0.07 to 0.20), and negligible after correcting for publication bias (d = 0.05, 95% confidence interval -0.09 to 0.14). These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

Good Scientific Practice and Ethics in Sports and Exercise Science: A Brief and Comprehensive Hands-on Appraisal for Sports Research

Sports and exercise training research is constantly evolving to maintain, improve, or regain psychophysical, social, and emotional performance. Exercise training research requires a balance between the benefits and the potential risks. There is an inherent risk of scientific misconduct and adverse events in most sports; however, there is a need to minimize it. We aim to provide a comprehensive overview of the clinical and ethical challenges in sports and exercise research. We also enlist solutions to improve method design in clinical trials and provide checklists to minimize the chances of scientific misconduct. At the outset, historical milestones of exercise science literature are summarized. It is followed by details about the currently available regulations that help to reduce the risk of violating good scientific practices. We also outline the unique characteristics of sports-related research with a narrative of the major differences between sports and drug-based trials. An emphasis is then placed on the importance of well-designed studies to improve the interpretability of results and generalizability of the findings. This review finally suggests that sports researchers should comply with the available guidelines to improve the planning and conduct of future research thereby reducing the risk of harm to research participants. The authors suggest creating an oath to prevent malpractice, thereby improving the knowledge standards in sports research. This will also aid in deriving more meaningful implications for future research based on high-quality, ethically sound evidence.

Effects of Wearable Fitness Trackers and Activity Adequacy Mindsets on Affect, Behavior, and Health: Longitudinal Randomized Controlled Trial

BACKGROUND

There is some initial evidence suggesting that mindsets about the adequacy and health consequences of one's physical activity (activity adequacy mindsets [AAMs]) can shape physical activity behavior, health, and well-being. However, it is unknown how to leverage these mindsets using wearable technology and other interventions.

OBJECTIVE

This research examined how wearable fitness trackers and meta-mindset interventions influence AAMs, affect, behavior, and health.

METHODS

A total of 162 community-dwelling adults were recruited via flyers and web-based platforms (ie, Craigslist and Nextdoor; final sample size after attrition or exclusion of 45 participants). Participants received an Apple Watch (Apple Inc) to wear for 5 weeks, which was equipped with an app that recorded step count and could display a (potentially manipulated) step count on the watch face. After a baseline week of receiving no feedback about step count, participants were randomly assigned to 1 of 4 experimental groups: they received either accurate step count (reference group; 41/162, 25.3%), 40% deflated step count (40/162, 24.7%), 40% inflated step count (40/162, 24.7%), or accurate step count+a web-based meta-mindset intervention teaching participants the value of adopting more positive AAMs (41/162, 25.3%). Participants were blinded to the condition. Outcome measures were taken in the laboratory by an experimenter at the beginning and end of participation and via web-based surveys in between. Longitudinal analysis examined changes within the accurate step count condition from baseline to treatment and compared them with changes in the deflated step count, inflated step count, and meta-mindset conditions.

RESULTS

Participants receiving accurate step counts perceived their activity as more adequate and healthier, adopted a healthier diet, and experienced improved mental health (Patient-Reported Outcomes Measurement Information System [PROMIS]-29) and aerobic capacity but also reduced functional health (PROMIS-29; compared with their no-step-count baseline). Participants exposed to deflated step counts perceived their activity as more inadequate; ate more unhealthily; and experienced more negative affect, reduced self-esteem and mental health, and increased blood pressure and heart rate (compared with participants receiving accurate step counts). Inflated step counts did not change AAM or most other outcomes (compared with accurate step counts). Participants receiving the meta-mindset intervention experienced improved AAM, affect, functional health, and self-reported physical activity (compared with participants receiving accurate step counts only). Actual step count did not change in either condition.

CONCLUSIONS

AAMs--induced by trackers or adopted deliberately--can influence affect, behavior, and health independently of actual physical activity.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03939572; https://www.clinicaltrials.gov/ct2/show/NCT03939572.

Long Term Effects of a Social Capital-Based Exercise Adherence Intervention for Breast Cancer Survivors With Moderate Fatigue: A Randomized Controlled Trial

OBJECTIVES

This study reports on the long-term effects of the Better Life After Cancer: Energy, Strength, and Support (BLESS) program, a 12-week social capital-based exercise adherence program for breast cancer survivors (BCS), implemented using a randomized controlled trial design. The study investigated outcomes related to cancer-related fatigue (CRF), quality of life (QOL), physical activity, depression, anxiety, sleep quality, and social capital.

METHODS

Participants who had moderate or greater CRF were randomly assigned to the intervention (n = 24), consisting of supervised and home-based exercise, or the control (n = 26), who received exercise leaflets. Generalized estimating equations models were fitted for the outcome variables. The assessment points were baseline (M1), immediately after completing the intervention at 12 weeks (M2), 1 month (M3), and 6 months post-intervention (M4).

RESULTS

A significant reduction in the total CRF score was found for both groups. We observed a significant time by group effect at M2, indicating a reduction of behavioral/severity CRF scores and a higher increase of physical activity. Also, there was an increase in the QOL score of both groups at M2, M3, and M4, compared to M1. Both groups had reduced anxiety at M3 and M4 compared to M1. The time by group effect for depression, sleep quality and social capital was not statistically significant.

CONCLUSION

This 12-week exercise adherence program improved behavioral/severity CRF and physical activity post-intervention. Both the experimental group and control group showed significant improvements in CRF, QOL, and anxiety domains compared to the baseline, which extended to 6 months post-intervention.

TRIAL REGISTRATION

Korean Clinical Research Information Service (KCT0005763).

Mechanisms, Mediators, and Moderators of the Effects of Exercise on Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is an adverse effect of neurotoxic antineoplastic agents commonly used to treat cancer. Patients with CIPN experience debilitating signs and symptoms, such as combinations of tingling, numbness, pain, and cramping in the hands and feet that inhibit their daily function. Among the limited prevention and treatment options for CIPN, exercise has emerged as a promising new intervention that has been investigated in approximately two dozen clinical trials to date. As additional studies test and suggest the efficacy of exercise in treating CIPN, it is becoming more critical to develop mechanistic understanding of the effects of exercise in order to tailor it to best treat CIPN symptoms and identify who will benefit most. To address the current lack of clarity around the effect of exercise on CIPN, we reviewed the key potential mechanisms (e.g., neurophysiological and psychosocial factors), mediators (e.g., anti-inflammatory cytokines, self-efficacy, and social support), and moderators (e.g., age, sex, body mass index, physical fitness, exercise dose, exercise adherence, and timing of exercise) that may illuminate the relationship between exercise and CIPN improvement. Our review is based on the studies that tested the use of exercise for patients with CIPN, patients with other types of neuropathies, and healthy adults. The discussion presented herein may be used to (1) guide oncologists in predicting which symptoms are best targeted by specific exercise programs, (2) enable clinicians to tailor exercise prescriptions to patients based on specific characteristics, and (3) inform future research and biomarkers on the relationship between exercise and CIPN.

Blood pressure and cardiac autonomic adaptations to isometric exercise training: A randomized sham-controlled study

Isometric exercise training (IET) is increasingly cited for its role in reducing resting blood pressure (BP). Despite this, few studies have investigated a potential sham effect attributing to the success of IET, thus dictating the aim of the present study. Thirty physically inactive males (n = 15) and females (n = 15) were randomly assigned into three groups. The IET group completed a wall squat intervention at 95% peak heart rate (HR) using a prescribed knee joint angle. The sham group performed a parallel intervention, but at an intensity (<75% peak HR) previously identified to be inefficacious over a 4-week training period. No-intervention controls maintained their normal daily activities. Pre- and post-measures were taken for resting and continuous blood pressure and cardiac autonomic modulation. Resting clinic and continuous beat-to-beat systolic (-15.2 ± 9.2 and -7.3 ± 5.6 mmHg), diastolic (-4.6 ± 5 and -4.5 ± 5.1), and mean (-7 ± 4.2 and -7.5 ± 5.3) BP, respectively, all significantly decreased in the IET group compared to sham and no-intervention control. The IET group observed a significant decrease in low-frequency normalized units of heart rate variability concurrent with a significant increase in high-frequency normalized units of heart rate variability compared to both the sham and no-intervention control groups. The findings of the present study reject a nonspecific effect and further support the role of IET as an effective antihypertensive intervention. Clinical Trials ID: NCT05025202.

Influence of motivational placebo-related factors on the effects of exercise treatment in depressive adolescents

Recent meta-analyses reveal a moderate effect of physical activity (PA) in the treatment of adolescent depression. However, not only the underlying neurobiological mechanisms, also the influences of placebo-related motivational factors (beliefs and expectancies in sporting, enjoyment and prior sports experiences), are still unclear. Based on the data of our prior study "Mood Vibes", we hypothesized that placebo-inherent factors like positive prior sports experiences and motivational factors, (positive beliefs, expectancies, and enjoyment related to PA), would increase the effects of an add-on exercise-therapy in juvenile depression. From 64 included depressed adolescents, 41 underwent an intensive add-on PA-therapy. Motivational factors were assessed using sport-specific scales. The changes in depression scores under treatment were rated by self-rating scale (German "Childhood Depression Inventory", (DIKJ)). A mixed model for repeated measures (MMRM) was used to analyze the effects of the different motivational variates on DIKJ. While prior sports experiences had no impact, motivational factors showed a significant effect on PA-induced changes in DIKJ scores (p = 0.002). The demotivated participants improved less, whereas it was sufficient to be neutral towards sporting to benefit significantly more. Motivational placebo-related factors (beliefs, expectancies and enjoyment regarding PA) affected the outcomes of an exercise treatment in depressed adolescents. Yet, a neutral mindset was sufficient to profit more from PA. Prior sporting in the sense of positive conditioning and as a protective factor did not play a role. Knowledge about these influences could in a second step help to develop tailored therapies.

Can the add-on placebo effect augment the physical and mental health outcomes of exercise? A meta-analysis

This study aimed to clarify whether the add-on placebo effect can augment the psychological and physiological benefits of exercise. The inclusion criteria were met by 18 studies with 1,221 participants. The add-on placebo effects promoted a more positive affect (g = 0.430), greater self-esteem (g = 0.454), improved cardiorespiratory fitness (g = 0.273), and decreased perceived exertion (g = 0.476) and blood pressure (g = 0.268). Improved affect benefits were moderated by placebo type (elaboration > external medium), self-selected exercise intensity (no > yes), and exercise type (running > nonspecific). The results support the proposal that the add-on placebo effect can provide significant positive benefits for exercisers, particularly in terms of psychological responses.

Association between Educational Level and Physical Activity in Chronic Disease Patients of Eastern Slovakia

Aims: This study aimed to investigate selected chronic diseases patients with different educational attainment regarding their awareness of and compliance with recommended physical activity. Method: This cross-sectional study was conducted from October 2018 to February 2019 in cooperation with chronic diseases clinics in eastern Slovakia. The study involved 893 patients. Results: People with higher education apparently recognise to a greater extent the importance of nutrition, diet, and the role of physical activity in treating their disease. Moreover, they have knowledge of physical exercises appropriate for their disease. Conversely, a noticeably higher number of less educated patients reported receiving general, respectively detailed information about the importance of physical activity in treating their disease. Differences in awareness of appropriate exercises and their implementation were not statistically significant. Conclusions: The results fail to prove educational attainment being a key determinant of chronic diseases. However, it can be reasonably argued that lower educational attainment may be a reliable risk signal of chronic diseases in later life.

Attempting to Separate Placebo Effects from Exercise in Chronic Pain: A Systematic Review and Meta-analysis

BACKGROUND

Pain is the most disabling characteristic of musculoskeletal disorders, and while exercise is promoted as an important treatment modality for chronic musculoskeletal conditions, the relative contribution of the specific effects of exercise training, placebo effects and non-specific effects such as natural history are not clear. The aim of this systematic review and meta-analysis was to determine the relative contribution of these factors to better understand the true effect of exercise training for reducing pain in chronic primary musculoskeletal pain conditions.

DESIGN

Systematic review with meta-analysis DATA SOURCES: MEDLINE, CINAHL, SPORTDiscus, EMBASE and CENTRAL from inception to February 2021. Reference lists of prior systematic reviews.

ELIGIBILITY CRITERIA

Randomised controlled trials of interventions that used exercise training compared to placebo, true control or usual care in adults with chronic primary musculoskeletal pain. The review was registered prospectively with PROSPERO (CRD42019141096).

RESULTS

We identified 79 eligible trials for quantitative analysis. Pairwise meta-analysis showed very low-quality evidence (GRADE criteria) that exercise training was not more effective than placebo (g [95% CI]: 0.94 [- 0.17, 2.06], P = 0.098, I² = 92.46%, studies: n = 4). Exercise training was more effective than true, no intervention controls (g [95% CI]: 0.99 [0.66, 1.32], P < 0.001, I² = 92.43%, studies: n = 42), usual care controls (g [95% CI]: 0.64 [0.44, 0.83], P < 0.001, I² = 76.52%, studies: n = 33), and when all controls combined (g [95% CI]: 0.84 [0.64, 1.04], P < 0.001, I² = 90.02%, studies: n = 79).

CONCLUSIONS

There is very low-quality evidence that exercise training is not more effective than non-exercise placebo treatments in chronic pain. Exercise training and the associated clinical encounter are more effective than true control or standard medical care for reductions in pain for adults with chronic musculoskeletal pain, with very low quality of evidence based on GRADE criteria.

Physical activity and moving more for health

Non-communicable diseases are a leading cause of death and levels are rising. Lifestyle changes, including physical activity, have benefits in all-cause mortality, cardiovascular and metabolic disease, respiratory conditions and cognitive and mental health. In some cancers, particularly colon, prostate and breast, physical activity improves quality of life and outcomes before, during and after treatment. Sedentary time is an independent risk factor with adverse effects in hospitalised patients. Mechanisms include anti-inflammatory effects and augmentation of physiological and neuroendocrine responses to stressors. Engaging patients is affected by barriers: for clinicians, awareness of guidelines and personal physical activity levels are important factors; for patients, barriers are influenced by life events, socioeconomic and cultural factors. Interventions to increase activity levels are effective in the short- and medium-term, including brief interventions. Face-to-face is more effective than remote advice and behavioural interventions are more effective than cognitive. There are no published guidelines for physical activity in hospitalised patients.

Safety and efficacy of short-term structured resistance exercise in Gulf War Veterans with chronic unexplained muscle pain: A randomized controlled trial

AIMS

Chronic widespread musculoskeletal pain (CMP) is a primary condition of Veterans suffering from Gulf War illness. This study evaluated the influence of resistance exercise training (RET) on symptoms, mood, perception of improvement, fitness, and total physical activity in Gulf War Veterans (GWV) with CMP.

MAIN METHODS

Fifty-four GWV with CMP were randomly assigned to 16 weeks of RET (n = 28) or wait-list control (n = 26). Supervised exercise was performed twice weekly starting at a low intensity. Outcomes, assessed at baseline, 6, 11 and 17 weeks and 6- and 12-months post-intervention, were: pain, fatigue, mood, sleep quality, perception of improvement, and physical activity via self-report and accelerometry. Muscular strength was assessed at baseline, 8 and 16 weeks. Accelerometer data yielded estimates of time spent in sedentary, light, and moderate-to-vigorous physical activities. Analyses used separate linear mixed models with group and time point as fixed effects. All models, except for perceived improvement, included baseline values as a covariate.

KEY FINDINGS

Participants assigned to RET completed 87% of training sessions and exhibited strength increases between 16 and 34% for eight lifts tested (Hedges' g range: 0.47-0.78). The treatment by time interaction for perceived improvement (F_1,163 = 16.94, p < 0.001) was characterized by greater perceived improvement since baseline for RET at each time point, until the 12-month follow-up. Effects were not significant for other outcomes (p > 0.05). RET caused no adverse events.

SIGNIFICANCE

After 16 weeks of RET, GWV with CMP reported improvements in their condition and exhibited increases in muscular strength, without symptom exacerbation or reductions in total physical activity.

Mental Well-Being or Ill-Being through Coaching in Adult Grassroots Sport: A Systematic Mapping Review

There is convincing evidence on the effects of sport and exercise on mental health and well-being. Less evidence is provided about how to achieve these benefits in the context of grassroots sport coaching. We systematically reviewed the scientific literature of three databases to narratively synthesize the current knowledge about which coaching-related factors influence well-being or ill-being, and how to promote mental health in adult athletes through sport coaches. The review includes 52 studies with different methodological and theoretical approaches and mental health outcomes. The wide range of themes were mapped and synthesized within two clusters, i.e., coaching behavior, antecedents, and context; and coach–athlete relationship and social support. The results highlight the importance of the promotion of empowering environments, autonomy-supportive coaching behavior, and coach–athlete relationship quality that relate to the satisfaction of basic psychological needs. The review also calls for a critical perspective, in the sense that the coaching context and working environment may not be empowering and supportive to the well-being of coaches and consequently to the athletes, and that coaches who want to provide autonomy-supportive environments may face various obstacles. Finally, the review synthesizes recommendations for the training of coaches, as one piece of a holistic mental health promotion.

Aerobic exercise or stretching as add-on to inpatient treatment of depression: Similar antidepressant effects on depressive symptoms and larger effects on working memory for aerobic exercise alone

BACKGROUND

Aerobic exercise (AE) has positive effects on symptom severity and cognitive symptoms of depression. Since data on AE as add-on to inpatient treatment in depression is still scarce, we conducted this double-blind randomized controlled study.

METHODS

Patients aged between 18 and 60 years were recruited into the study if Hamilton Depression Rating Scale 17 (HDRS-17) score was >16. Participants were randomly assigned to either AE or basic stretching activities (control), which took place 3x/week for 6 weeks. Primary outcome was depression severity as assessed with the HDRS-17 and the Beck Depression Inventory (BDI). Further physiological and psychological variables and cognitive performance were assessed as secondary outcomes.

RESULTS

Forty-two patients were included in the analysis (exercise: n = 22; control: n = 20). Regardless of group allocation, we found a significant short-term time effect for symptom-severity (HDRS17: p<0.001, η²=0.70; BDI: p<0.001, η²=0.51), mental toughness (p<0.001, η²=0.32), physical self-description endurance score (p = 0.013, η²=0.16), cognitive flexibility (p = 0.013, η²=0.14), and body mass index (BMI) (p = 0.006, η²=0.19). Working memory showed a significant time by group interaction in favor of AE (p = 0.043, η²=0.10). Short-term effects on symptom severity, mental toughness and BMI remained stable across the 6-month follow-up period. Finally, self-reported physical activity increased significantly from baseline to follow-up (p = 0.014, η²=0.15).

LIMITATIONS

The sample-size is rather small. The control intervention might have been too active as to find a time by group interaction for symptom severity.

CONCLUSIONS

AE was associated with comparably large depression alleviation vs. stretching and with add-on benefits on working memory.

Resistance exercise training for anxiety and worry symptoms among young adults: a randomized controlled trial

This trial quantified the effects of ecologically-valid resistance exercise training (RET) on anxiety and worry symptoms among young adults. Young adults not meeting criteria for subclinical, or analogue Generalized Anxiety Disorder (AGAD) were randomized to an eight-week RET intervention, or eight-week wait-list. AGAD status was determined using validated cut-scores for both the Psychiatric Diagnostic Screening Questionnaire-Generalized Anxiety Disorder subscale (≥ 6) and Penn State Worry Questionnaire (≥ 45). The primary outcome was anxiety symptoms measured with the Trait Anxiety subscale of the State-Trait Anxiety Inventory. The RET was designed according to World Health Organization and American College of Sports Medicine guidelines. RM-ANCOVA examined differences between RET and wait-list over time. Significant interactions were decomposed with simple effects analysis. Hedges' d effect sizes quantified magnitude of differences in change between RET and wait-list. Twenty-eight participants (64% female) fully engaged in the trial (mean age: 26.0 ± 6.2y, RET: n = 14; Wait-list: n = 14). A significant group X time interaction was found for anxiety symptoms (F_(3,66) = 3.60, p ≤ 0.019; d = 0.85, 95%CI: 0.06 to 1.63). RET significantly reduced anxiety symptoms from baseline to post-intervention (mean difference =  - 7.89, p ≤ 0.001). No significant interaction was found for worry (F_(3,69) = 0.79, p ≥ 0.50; d =  - 0.22, 95%CI: - 0.96 to 0.53). Ecologically-valid RET significantly improves anxiety symptoms among young adults.Trial Registration: Clinicaltrials.gov Identifier: NCT04116944, 07/10/2019.

Home-based motor imagery intervention improves functional performance following total knee arthroplasty in the short term: a randomized controlled trial

Background

Motor imagery (MI) is effective in improving motor performance in the healthy asymptomatic adult population. However, its possible effects among older orthopaedic patients are still poorly investigated. Therefore, this study explored whether the addition of motor imagery to routine physical therapy reduces the deterioration of quadriceps muscle strength and voluntary activation (VA) as well as other variables related to motor performance in patients after total knee arthroplasty (TKA).

Methods

Twenty-six patients scheduled for TKA were randomized to either MI practice combined with routine physical therapy group (MIp) or to a control group receiving physical therapy alone (CON). MIp consisted of maximal voluntary isometric contraction (MViC) task: 15 min/day in the hospital, then 5 times/week in their homes for 4 weeks. MViC and VA of quadriceps muscle, knee flexion and extension range of motion, pain level, along with a Timed Up-and-Go Test (TUG) and self-reported measure of physical function (assessed using the Oxford Knee Score questionnaire [OKS]) were evaluated before (PRE) and 1 month after surgery (POST).

Results

Significantly better rehabilitation outcomes were evident on the operated leg for the MIp group compared to CON: at POST, the MIp showed lower strength decrease (p = 0.012, η²= 0.237) and unaltered VA, significantly greater than CON (p = 0.014, η²= 0.227). There were no significant differences in knee flexion and extension range of motion and pain level (p > 0.05). Further, MIp patients performed better in TUG (p < 0.001, η²= 0.471) and reported better OKS scores (p = 0.005, η²= 0.280). The non-operated leg showed no significant differences in any outcomes at POST (all p > 0.05). In addition, multiple linear regression analysis showed that failure of voluntary activation explained 47% of the quadriceps muscle strength loss, with no significant difference in perceived level of pain.

Conclusion

MI practice, when added to physical therapy, improves both objective and subjective measures of patients’ physical function after TKA, and facilitates transfer of MI strength task on functional mobility.

Trial registration

Retrospectively registered on ClinicalTrials.govNCT03684148

Advancing the understanding of placebo effects in psychological outcomes of exercise: Lessons learned and future directions

Despite the apparent strength of scientific evidence suggesting that psychological benefits result from both acute and chronic exercise, concerns remain regarding the extent to which these benefits are explained by placebo effects. Addressing these concerns is methodologically and at times conceptually challenging. However, developments in the conceptualisation and study of placebo effects from the fields of psychology, neuroscience, pharmacology, and human performance offer guidance for advancing the understanding of placebo effects in psychological responses to exercise. In clinical trials, expectations can be measured and experimentally manipulated to better understand the influence of placebo effects on treatment responses. Further, compelling evidence has shown that the contribution of placebo effects and their underlying neurobiological mechanisms to treatment effects can be measured without administering a traditional placebo (e.g. inert substance) by leveraging psychological factors such as expectations and conditioning. Hence, the purpose of this focused review is to integrate lessons such as these with the current body of literature on placebo effects in psychological responses to exercise and provide recommendations for future research directions.

Physical Activity for the Treatment of Adolescent Depression: A Systematic Review and Meta-Analysis

Background: A noticeable proportion of adolescents with depression do not respond to guideline recommended treatment options. This systematic review and meta-analysis investigated the effectiveness of physical activity interventions as an alternative or complementary treatment for adolescents (12-18 years) with depression. The characteristics of the physical activity treatment that were most effective in reducing symptoms in adolescents with depression and the impact of methodological shortcomings in the existing research were also examined. Methods: Medline, PsycINFO, SPORTDiscus, ProQuest, and CENTRAL were searched for eligible records. Effect size estimates were pooled based on the application of a random-effects model. Potential moderation by physical activity characteristics (i.e., intensity, type, context, and time frame) and methodological features (i.e., type of control group and diagnostic tool to identify depression at baseline) was investigated by means of subgroup analyses and meta-regressions. The certainty of evidence was assessed by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. The primary outcome was the antidepressant effect of physical activity at postintervention measurement time point. As secondary outcomes, the sustainability of effects after the end of physical activity treatment and the acceptability of physical activity treatments were assessed. Overall, 10 studies were included in the qualitative synthesis and 9 studies involving 431 patients were included in the quantitative synthesis. Results: A moderate, significant antidepressant effect of physical activity was found (Hedges' g = -0.47, 95% CI = -0.71 to -0.24). Heterogeneity was small (T2 = 0.0313, I 2 = 27%, p = 0.18). However, the certainty of evidence was downgraded to low because the included studies contained serious methodological limitations. Moderator analyses revealed that session intensity significantly moderated the antidepressant effect of physical activity. Moreover, noticeably smaller effect sizes were found in studies that used non-physical activity sham treatments as control treatments (e.g., playing board games), compared to studies that used no control group treatments. Only three studies assessed the sustainability of effects after the end of physical activity treatment. The results suggest that the antidepressant effects further increase after the end of physical activity interventions. There was no significant difference in dropout risk between the physical activity and control groups. Conclusions: This review suggests that physical activity is effective in treating depression in adolescents. Physical activity sessions should be at least moderately intense [rate of perceived exertion (RPE) between 11 and 13] to be effective. Furthermore, our results suggest that physical activity treatments are well accepted. However, the low methodological quality in included studies might have led to effect overestimation. Therefore, more studies with higher methodological quality are needed to confirm the recommendation for physical activity treatments in adolescents with depression.

Not All Promotion Is Good Promotion: The Pitfalls of Overexaggerated Claims and Controlling Language in Exercise Messaging

Across 2 studies, the authors explored reactance effects to overexaggerated claims and controlling language in exercise messaging. In Study 1, participants received either a message exaggerating the benefits of an upcoming exercise session or no message. They subsequently undertook a mundane exercise session led by an instructor, which was either need supportive or "realistically controlling." Relative to no-message participants, those who had read the message reported less positive evaluations of the session. These results were observed despite participants in the message condition holding more positive presession expectations, and the effect was apparent even for those who received need-supportive instruction. In Study 2, participants read an advertisement that was written in either autonomy-supportive language or controlling language. Despite reporting comparable expectations, participants who received a controlling-language message reported significantly greater anger and freedom threat-factors commonly linked to contrast effects. These studies highlight the operation of message-driven contrast effects in exercise.

Influence of stretching exercises in musculoskeletal pain in nursing professionals

Abstract Introduction: Nursing professionals (NPs) experience musculoskeletal pain that leads them to leave work. Objective: To analyze the effects of muscle stretching exercises (MSE) on pain among NPs. Method: This is a randomized controlled parallel experiment, in which 28 NPs (7 men and 21 women) were allocated into experimental (EG, n = 15; 47.4 years ± 9.5) and control (CG, n = 13; 39.15 years ± 9.6) groups. MSEs were performed for two months, three days a week, 40 min per session. A visual numeric scale was used, for which the intensity ranged from 0 (no pain) to 10 (maximum pain). The research was registered at the Brazilian Clinical Trials Registry website (TRIAL: RBR- 8chg6q). For statistics, the Shapiro-Wilk, T-independent and two-way ANOVA tests were applied for repeated measures with Tukey’s post-hoc test (P ≤ 0.05). Results: Most NPs work on weekends (68%) and/or have other professional activities (60.7%); 42.9% had to miss work at least once in the year prior to the survey and 66.7% of those were due to medical reasons; 42.9% work more than 10 hours/day. Of the NPs, 89.3% of the volunteers in both groups lived daily with pain in some region of the body. Pain decreased after the MSE program was initiated in the EG (p = 0.001) and differed from the CG (p = 0.002). Conclusion: MSEs were beneficial for pain reduction in NPs.

Effects of physical activity recommendations on mindset, behavior and perceived health

This research sought to understand if physical activity recommendations––an integral component of many interventions aiming to promote physical activity––may have unexpected effects on individuals’ mindsets (in this case about the adequacy and health consequences of their physical activity) that can strengthen or weaken recommendation effectiveness. Participants were students and staff at a U.S. West Coast private university, recruited between 2016 and 2019. Two experiments with one-week follow-up periods investigated the effects of viewing recommendations that prescribe a lower (vs. higher) amount of physical activity and provide a liberal (vs. stringent) definition of what counts as physical activity on individuals’ mindsets about the adequacy and health consequences of their physical activity, as well as physical activity-related self-efficacy, physical activity behavior, and perceived health. Study 1 (N = 157) showed that exposure to low-and-liberal recommendations (vs. high-and-stringent recommendations) caused participants to adopt the mindset that their physical activity was more adequate, which in turn predicted greater engagement in physical activity and perceived health one week later. Study 2 (N = 272) showed that regardless of definition of physical activity (liberal vs. stringent), a lower (vs. higher) amount of recommended physical activity led participants to adopt the mindset that their activity was more adequate. This more adaptive mindset predicted greater self-efficacy and engagement in physical activity in the following week, in addition to better perceived health. Rather than inducing complacency, recommendations prescribing a relatively lower (vs. higher) amount of physical activity may be more effective at promoting physical activity and health by inducing adaptive mindsets.

Effect of branched-Chain Amino Acid Supplementation on Muscle Soreness following Exercise: A Meta-Analysis

Abstract. Delayed onset muscle soreness (DOMS) is a symptom of exercise-induced muscle damage that occurs following exercise. Previous research has indicated that branched-chain amino acid (BCAA) supplementation may attenuate exercise-induced muscle damage that causes delayed onset muscle soreness, however the results are inconsistent. The primary aim of this study was to examine the previous literature assessing the effect of BCAA supplementation on DOMS following an acute bout of exercise in adults. This review was conducted in accordance with PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses), and identified peer-reviewed articles comparing a BCAA supplement to a placebo non-BCAA supplement following an acute bout of exercise. An electronic search of three databases (EbscoHost, Web of Science, and SPORTDiscus) yielded 42 articles after duplicates were removed. All studies included in the current analyis were: 1) peer-reviewed publications; 2) available in English; 3) utilized a random control design that compared a BCAA group to a placebo control group following exercise; 4) and assessed soreness of muscle tissue during recovery. DOMS was assessed in 61 participants following ingestion of a BCAA supplement over the course of these interventions. The cumulative results of 37 effects gathered from 8 studies published between 2007 and 2017 indicated that BCAA supplementation reduced DOMS following exercise training (ES = 0.7286, 95% CI: 0.5017 to 0.9555, p < 0.001). A large decrease in DOMS occurs following BCAA supplementation after exercise compared to a placebo supplement.

Reconceptualizing the measurement of expectations to better understand placebo and nocebo effects in psychological responses to exercise

The understanding of placebo and nocebo effects in psychological responses to exercise may be improved by measuring expectations. Despite availability of several validated expectation measures, we argue for using scales that take both positive and negative expectations for exercise-induced changes into account. A cross-sectional survey was used to collect information on positive and negative expectations pertaining to how exercise would affect 14 different outcomes related to psychological health (n = 966). Outcomes for which a majority of the sample (>50%) reported positive expectations for exercise-induced changes included: psychological well-being (75.3%), depression (74.3%), relaxation (74.2%), sleep quality (73.3%), stress (72.2%), anxiety (69.8%), energy (67.1%), and attention (60.2%). Outcomes for which a majority of the sample (>50%) reported a negative expectation for exercise-induced changes were muscle pain (66.3%), fatigue (57.3%), and joint pain (50.7%). Across all 14 outcomes, the percentage of participants with negative expectations for exercise-induced changes ranged from 5.9 to 66.3%. Elucidating the potential presence of placebo and nocebo effects through measurement of expectations may improve the understanding of variability in the direction and magnitude of exercise-related effects on psychological health. Although there were only 3 outcomes for which the majority of participants reported negative expectations, we found that negative expectations were present to some degree for all 14 outcomes. Thus, for researchers who wish to characterize expectations in studies of psychological responses to exercise, we recommend using measures that give equal consideration to positive and negative expectations.

#MindinBody - feasibility of vigorous exercise (Bikram yoga versus high intensity interval training) to improve persistent pain in women with a history of trauma: a pilot randomized control trial

BACKGROUND

The neurobiology of persistent pain shares common underlying psychobiology with that of traumatic stress. Modern treatments for traumatic stress often involve bottom-up sensorimotor retraining/exposure therapies, where breath, movement, balance and mindfulness, are used to target underlying psychobiology. Vigorous exercise, in particular Bikram yoga, combines many of these sensorimotor/exposure therapeutic features. However, there is very little research investigating the feasibility and efficacy of such treatments for targeting the underlying psychobiology of persistent pain.

METHODS

This study was a randomized controlled trail (RCT) comparing the efficacy of Bikram yoga versus high intensity interval training (HIIT), for improving persistent pain in women aged 20 to 50 years. The participants were 1:1 randomized to attend their assigned intervention, 3 times per week, for 8 weeks. The primary outcome measure was the Brief Pain Inventory (BPI) and further pain related biopsychosocial secondary outcomes, including SF-36 Medical Outcomes and heart rate variability (HRV), were also explored. Data was collected pre (t0) and post (t1) intervention via an online questionnaire and physiological testing.

RESULTS

A total of 34 women were recruited from the community. Analyses using ANCOVA demonstrated no significant difference in BPI (severity plus interference) scores between the Bikram yoga (n = 17) and the HIIT (n = 15). Women in the Bikram yoga group demonstrated significantly improved SF-36 subscale physical functioning: [ANCOVA: F(1, 29) = 6.17, p = .019, partial eta-squared effect size (η_p²) = .175 and mental health: F(1, 29) = 9.09, p = .005, η_p² = .239; and increased heart rate variability (SDNN): F(1, 29) = 5.12, p = .013, η_p² = .150, scores compared to the HIIT group. Across both groups, pain was shown to decrease, no injuries were experienced and retention rates were 94% for Bikram yoga and 75% for HIIT .

CONCLUSIONS

Bikram yoga does not appear a superior exercise compared to HIIT for persistent pain. However, imporvements in quality of life measures and indicator of better health were seen in the Bikram yoga group. The outcomes of the present study suggest vigorous exercise interventions in persistent pain cohorts are feasible.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ( ACTRN12617001507370 , 26/10/2017).

Physical activity is indirectly associated with pain in college women through associations with somatization and panic disorder symptoms: a cross-sectional study

PURPOSE

This study tested whether the severity of somatization, panic, generalized anxiety, and depression symptoms mediated relationships between physical activity and pain using structural equation modeling.

METHODS

College women (n = 1036; mean = SD age of 19.7 ± 3.0 years) reported past week physical activity and the presence of persistent pain (≥1 month). The Psychiatric Diagnostic Screening Questionnaire assessed hypothesized mediators of physical activity effects on pain via symptoms of generalized anxiety, panic, major depressive disorder, and somatization disorder.

RESULTS

The percentage of the sample screening positive was 15.7% for generalized anxiety, 5.8% for panic, 11.0% for major depressive, and 16.0% for somatization. The hypothesized model had good fit and accounted for a significant amount of variance in pain (9.1%). Direct paths from physical activity to somatization, generalized anxiety, major depressive disorder, and panic disorder were significant. Paths to pain were significant from somatization and panic disorder. The path from physical activity to pain was not direct but indirect and through significant paths to pain from somatization and panic disorder. Each standard deviation increase in physical activity decreased the probability of pain by 11.0% through panic disorder and 10.7% through somatization disorder.

CONCLUSIONS

Physical activity is associated with pain indirectly through associations with panic disorder and somatization disorder symptoms in college women.

Effects of placebo on bench throw performance of Paralympic weightlifting athletes: a pilot study

BACKGROUND

The aim of the present study was to analyse the effects of placebo on bench throw performance in Paralympic weightlifting athletes.

METHODS

The study involved four Paralympic weightlifting male athletes (age: 40.25 ± 9.91 years, weight: 60.5 ± 8.29 kg, height: 1.60 ± 0.15 m) that visited the laboratory in three occasions, separated by 72 h. In the first session, the athletes were tested for bench press one repetition maximum (1RM). The other two sessions were performed in a randomized counter-balanced order and involved bench throw tests performed either after taking placebo while being informed that the capsule contained caffeine or without taking any substance (control). The bench throw tests were performed with loads corresponding to 50, 60, 70 and 80% of the bench press 1RM.

RESULTS

According to the results, mean velocity (∆: 0.08 m/s, ES 0.36, p < 0.05) and mean propulsive velocity (∆: 0.11 m/s, ES 0.49, p < 0.05) at 50% of 1RM were significantly higher during placebo than control (p < 0.05). However, there were no difference between control and placebo for 60, 70 and 80% of 1RM (p > 0.05).

CONCLUSION

Our results suggest that placebo intake, when the athletes were informed they were taking caffeine, might be an efficient strategy to improve the performance of explosive movements in Paralympic weightlifting athletes when using low-loads. This brings the possibility of using placebo in order to increase performance, which might reduce the risks associated with ergogenic aids, such as side-effects and positive doping testing.

How does yoga reduce stress? Embodied cognition and emotion highlight the influence of the musculoskeletal system

Yoga is an increasingly popular activity, perhaps because of its association with stress reduction and relaxation - an association that is generally supported by empirical evidence. Understanding of the mediating variables is, however, limited. Given that, the purpose of this paper is to present a theoretical perspective that encourages systematic research regarding the relationship between yoga, stress, and musculoskeletal activity. This embodied perspective parallels popular interest in the mind-body connection and emphasizes the influence of body position on thinking as well as emotion. Those influences take on added meaning in the context of the Cognitive Appraisal Theory and the Biopsychosocial Model of Challenge and Threat. Investigations of embodied cognition suggest that yoga may reduce stress by affecting the way individuals appraise stressors. The combination of body position and common components of yoga practice may also contribute to that effect, particularly when considering thoughts about the self and feelings of confidence. Findings regarding embodied emotion make a similar contribution to understanding the implications of previous research findings and common yoga practices. Considering yoga and stress from an embodied perspective also highlights the role of the musculoskeletal system in the stress process, leading to the question of whether yoga influences stress by directly influencing the musculoskeletal system, indirectly by influencing awareness of that system, or through a combination of the two. Those questions, in turn, highlight the importance of expanding investigations of psychological processes, body position, musculoskeletal activity during yoga, and the interactions between those variables.

The Effects of Resistance Exercise Training on Anxiety: A Meta-Analysis and Meta-Regression Analysis of Randomized Controlled Trials

BACKGROUND

The salutary effects of resistance exercise training (RET) are well established, including increased strength and function; however, less is known regarding the effects of RET on mental health outcomes. Aerobic exercise has well-documented positive effects on anxiety, but a quantitative synthesis of RET effects on anxiety is needed.

OBJECTIVES

To estimate the population effect size for resistance exercise training (RET) effects on anxiety and to determine whether variables of logical, theoretical, and/or prior empirical relation to anxiety moderate the overall effect.

METHODS

Thirty-one effects were derived from 16 articles published before February 2017, located using Google Scholar, MEDLINE, PsycINFO, PubMed, and Web of Science. Trials involved 922 participants (mean age = 43 ± 21 years, 68% female/32% male) and included both randomization to RET (n = 486) or a non-active control condition (n = 436), and a validated anxiety outcome measured at baseline, mid-, and/or post-intervention. Hedges' d effect sizes were computed and random effects models were used for all analyses. Meta-regression quantified the extent to which participant and trial characteristics moderated the mean effect.

RESULTS

RET significantly reduced anxiety symptoms (Δ = 0.31, 95% CI 0.17-0.44; z = 4.43; p < 0.001). Significant heterogeneity was not indicated (Q _T(30) = 40.5, p > 0.09; I ² = 28.3%, 95% CI 10.17-42.81); sampling error accounted for 77.7% of observed variance. Larger effects were found among healthy participants (Δ = 0.50, 95% CI 0.22-0.78) compared to participants with a physical or mental illness (Δ = 0.19, 95% CI 0.06-0.31, z = 2.16, p < 0.04). Effect sizes did not significantly vary according to sex (β = -0.31), age (β = -0.10), control condition (β = 0.08), program length (β = 0.07), session duration (β = 0.08), frequency (β = -0.10), intensity (β = -0.18), anxiety recall time frame (β = 0.21), or whether strength significantly improved (β = 0.19) (all p ≥ 0.06).

CONCLUSIONS

RET significantly improves anxiety symptoms among both healthy participants and participants with a physical or mental illness. Improvements were not moderated by sex, or based on features of RET. Future trials should compare RET to other empirically-supported therapies for anxiety.

The psychological effects of physical exercise: A controlled study of the placebo effect

The research on well-being and physical exercise point to the possibility of a placebo effect. This study analyzes the effect of expectancy manipulation on psychological (well-being and self-esteem) and physical (agility and cardiorespiratory fitness) outcomes after a seven-week program of aerobic training. 114 undergraduate students (age M = 19.81, SD = 1.75; 86.1% women) were randomized into G1 - No Exercise (n = 13), G2 - Exercise only (n = 15), G3 - Exercise + Manipulation of expectations: No psychological effect (n = 17) and G4 - Exercise + Manipulation of expectations: Psychological effect (n = 21). Outcome measures were the Rosenberg Self-Esteem Scale, the Well-Being subscale of the Subjective Exercise Experiences Scale, the Agility T-test and the 20-meter Shuttle Run Test. Paired t-tests showed significant improvements from baseline in self-esteem, agility, and cardiovascular fitness for the exercise groups. G4 also showed a significant improvement in well-being. ANCOVA with adjustments for the baseline measures was used to test between-group differences at the end of the program. The only significant differences at posttest were between G1 and the exercise groups. The data do not support a differential effect of elevated expectations of psychological benefits on the participants' self-esteem or psychological well-being after an aerobic training program. Future research should analyze whether reinforcing expectations more frequently throughout the program might show a more robust influence.

Consensus statement on placebo effects in sports and exercise: The need for conceptual clarity, methodological rigour, and the elucidation of neurobiological mechanisms

In June 2017 a group of experts in anthropology, biology, kinesiology, neuroscience, physiology, and psychology convened in Canterbury, UK, to address questions relating to the placebo effect in sport and exercise. The event was supported exclusively by Quality Related (QR) funding from the Higher Education Funding Council for England (HEFCE). The funder did not influence the content or conclusions of the group. No competing interests were declared by any delegate. During the meeting and in follow-up correspondence, all delegates agreed the need to communicate the outcomes of the meeting via a brief consensus statement. The two specific aims of this statement are to encourage researchers in sport and exercise science to 1. Where possible, adopt research methods that more effectively elucidate the role of the brain in mediating the effects of treatments and interventions. 2. Where possible, adopt methods that factor for and/or quantify placebo effects that could explain a percentage of inter-individual variability in response to treatments and intervention.

Treating depression with physical activity in adolescents and young adults: a systematic review and meta-analysis of randomised controlled trials

We aimed to establish the treatment effect of physical activity for depression in young people through meta-analysis. Four databases were searched to September 2016 for randomised controlled trials of physical activity interventions for adolescents and young adults, 12-25 years, experiencing a diagnosis or threshold symptoms of depression. Random-effects meta-analysis was used to estimate the standardised mean difference (SMD) between physical activity and control conditions. Subgroup analysis and meta-regression investigated potential treatment effect modifiers. Acceptability was estimated using dropout. Trials were assessed against risk of bias domains and overall quality of evidence was assessed using GRADE criteria. Seventeen trials were eligible and 16 provided data from 771 participants showing a large effect of physical activity on depression symptoms compared to controls (SMD = -0.82, 95% CI = -1.02 to -0.61, p < 0.05, I2 = 38%). The effect remained robust in trials with clinical samples (k = 5, SMD = -0.72, 95% CI = -1.15 to -0.30), and in trials using attention/activity placebo controls (k = 7, SMD = -0.82, 95% CI = -1.05 to -0.59). Dropout was 11% across physical activity arms and equivalent in controls (k = 12, RD = -0.01, 95% CI = -0.04 to 0.03, p = 0.70). However, the quality of RCT-level evidence contributing to the primary analysis was downgraded two levels to LOW (trial-level risk of bias, suspected publication bias), suggesting uncertainty in the size of effect and caution in its interpretation. While physical activity appears to be a promising and acceptable intervention for adolescents and young adults experiencing depression, robust clinical effectiveness trials that minimise risk of bias are required to increase confidence in the current finding. The specific intervention characteristics required to improve depression remain unclear, however best candidates given current evidence may include, but are not limited to, supervised, aerobic-based activity of moderate-to-vigorous intensity, engaged in multiple times per week over eight or more weeks. Further research is needed. (Registration: PROSPERO-CRD 42015024388).

Effects of Resistance Training on Fatigue-Related Domains of Quality of Life and Mood During Pregnancy: A Randomized Trial in Pregnant Women With Increased Risk of Back Pain

OBJECTIVE

The aim of the study was to test whether the adoption of twice weekly, low-to-moderate intensity resistance training during weeks 22 to 34 of pregnancy can improve quality of life and mood.

METHODS

A parallel-group trial was conducted. Women in their second trimester (N = 134) were randomly assigned to 12 weeks of wait list, bimonthly pregnancy education classes, or twice weekly low-to-moderate intensity resistance training. Resistance training involved one abdominal exercise with no external load and five exercises (leg extension, leg press, arm lat pull, leg curl, and lumbar extension) with an external load that gradually progressed, and the total active exercise time during each exercise session was approximately 17 minutes. Quality of life and mood were measured before and after the interventions using the 36-item Short Form Health Survey and Profile of Mood States. Intent-to-treat mixed-model analyses of variance (3 groups by 2 times, pre- and postintervention) tested the hypothesis that outcomes would worsen for the controls and not change or improve for the resistance training group.

RESULTS

The group by time interaction (F(2,131) = 3.144, η = .046, p = .046) for 36-item Short Form Health Survey vitality and subsequent simple main effects showed that scores were unchanged across time after resistance training (-1.8 (14.8)) but significantly decreased for the education (-6.44 (12.69), t = 3.408, df = 44, p = .001) and wait list (-9.11 (14.78), t = 4.135, df = 44, p < .001) groups, whereas posttest vitality scores for the pregnancy group (45.9 (16.9)) were significantly higher than the wait list (40.1 (16.3), t = 1.989, df = 87, p = .05) but not the education group (42.1 (15.4), p = .27). Profile of mood states fatigue scores showed a similar pattern.

CONCLUSIONS

Adverse changes in symptoms of energy and fatigue during pregnancy are attenuated by adopting low-to-moderate intensity resistance training.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov, NCT02557893.

Effect of continuous progressive resistance training during hemodialysis on body composition, physical function and quality of life in end-stage renal disease patients: a randomized controlled trial

Objective:

This study aimed to investigate the effect of continuous progressive resistance training on body composition, functional capacity and self-reported quality of life in end-stage renal disease patients.

Design:

A randomized controlled trial.

Subjects:

The study included 52 hemodialysis patients (aged 55.7 ± 14.03 years) randomized into exercise (progressive resistance training (PRT), n = 28) or control (CON, n = 24) groups.

Intervention:

Patients randomized into the PRT group received prescribed strength exercises in two sets of 15–20 repetitions, in a repetition maximum training zone regime, thrice a week for 12 weeks, during hemodialysis. Patients randomized into the CON group received a sham-exercise with active mobilization of the arms and legs without load and progression.

Main outcome measure:

Body composition using dual-energy X-ray absorptiometry (DXA), strength using handgrip dynamometry (HGS), repeated sit-to-stand test (STT), 6-minute walk test, flexibility and the SF-36 questionnaire (quality of life (QoL)) were assessed at baseline and at 12 weeks.

Results:

Leg lean mass ( P = 0.04, effect size (ES) of 0.56), bone mineral content ( P = 0.02, ES of 0.65), leg strength in STT repetitions ( P = 0.01, ES of 0.66) and flexibility ( P < 0.01, ES of 1.03) were significantly improved in the PRT group compared to the CON group. Walking capacity, HGS and QoL were not different between the groups.

Conclusion:

12 weeks of PRT with a repetition maximum training zone regime provided significant load to increase leg lean mass and STT performance as well as bone mineral content, compared to the CON, which continued to deteriorate. There was lack of efficacy on walking test, HGS and QoL.

Physical Exercise in Major Depression: Reducing the Mortality Gap While Improving Clinical Outcomes

Major depression shortens life while the effectiveness of frontline treatments remains modest. Exercise has been shown to be effective both in reducing mortality and in treating symptoms of major depression, but it is still underutilized in clinical practice, possibly due to prevalent misperceptions. For instance, a common misperception is that exercise is beneficial for depression mostly because of its positive effects on the body ("from the neck down"), whereas its effectiveness in treating core features of depression ("from the neck up") is underappreciated. Other long-held misperceptions are that patients suffering from depression will not engage in exercise even if physicians prescribe it, and that only vigorous exercise is effective. Lastly, a false assumption is that exercise may be more harmful than beneficial in old age, and therefore should only be recommended to younger patients. This narrative review summarizes relevant literature to address the aforementioned misperceptions and to provide practical recommendations for prescribing exercise to individuals with major depression.

An Examination of Exercise-Induced Feeling States and Their Association With Future Participation in Physical Activity Among Older Adults

Although exercise-induced feeling states may play a role in driving future behavior, their role in relation to older adults' participation in physical activity (PA) has seldom been considered. The objectives of this study were to describe changes in older adults' feeling states during exercise, and examine if levels of and changes in feeling states predicted their future participation in PA. Self-reported data on feeling states were collected from 82 older adults immediately before, during, and after a moderate-intensity exercise session, and on participation in PA 1 month later. Data were analyzed using latent growth modeling. Feelings of revitalization, positive engagement, and tranquility decreased during exercise, whereas feelings of physical exhaustion increased. Feelings of revitalization immediately before the exercise session predicted future participation in PA; changes in feeling states did not. This study does not provide empirical evidence that older adults' exercise-induced feeling states predict their future participation in PA.

Exercise and cancer-related fatigue in adults: a systematic review of previous systematic reviews with meta-analyses

BACKGROUND

Conduct a systematic review of previous systematic reviews with meta-analysis to determine the effects of exercise (aerobic, strength or both) on cancer-related-fatigue (CRF) in adults with any type of cancer.

METHODS

Systematic reviews with meta-analyses of previous randomized controlled trials published through July of 2016 were included by searching six electronic databases and cross-referencing. Dual-selection and data abstraction were conducted. Methodological quality was assessed using the Assessment of Multiple Systematic Reviews (AMSTAR) instrument. Standardized mean differences (SMD) that were pooled using random-effects models were included as the effect size. In addition, 95% prediction intervals (PI), number needed-to-treat (NNT) and percentile improvements were calculated.

RESULTS

Sixteen studies representing 2 to 48 SMD effect sizes per analysis (mean ± SD, 7 ± 8, median = 5) and 37 to 3254 participants (mean ± SD, 633 ± 690, median = 400) were included. Length of training lasted from 3 to 52 weeks (mean ± SD, 14.6 ± 3.1, median = 14), frequency from 1 to 10 times per week (mean ± SD, 3.4 ± 0.8, median = 3), and duration from 10 to 120 min per session (mean ± SD, 44.3 ± 5.5, median = 45). Adjusted AMSTAR scores ranged from 44.4% to 80.0% (mean ± SD, 68.8% ± 12.0%, median = 72.5%). Overall, mean SMD improvements in CRF ranged from -1.05 to -0.01, with 22 of 55 meta-analytic results (52.7%) statistically significant (non-overlapping 95% CI). When PI were calculated for results with non-overlapping 95% CI, only 3 of 25 (12%) yielded non-overlapping 95% PI favoring reductions in CRF. Number needed-to-treat and percentile improvements ranged from 3 to 16 and 4.4 to 26.4, respectively.

CONCLUSIONS

A lack of certainty exists regarding the benefits of exercise on CRF in adults. However, exercise does not appear to increase CRF in adults.

TRIAL REGISTRATION

PROSPERO Registration # CRD42016045405 .

The Effect of Light-Intensity Cycling on Mood and Working Memory in Response to a Randomized, Placebo-Controlled Design

OBJECTIVE

Prior attempts to measure psychological responses to exercise are potentially limited by a failure to account for participants' expectations, the absence of a valid exercise placebo, and demand characteristics. The purpose of this study was to explore the main and interactive effects of a manipulation designed to increase expectations about the psychological benefits of an acute bout of active, light-intensity (treatment), and passive (placebo) cycling on mood and cognition. Demand characteristics were attenuated during recruitment, informed consent, and interactions with test administrators by communicating to participants that the study purpose was to assess the effects of active and passive cycling on respiration, heart rate, and muscle activation.

METHODS

A repeated-measures, randomized, placebo-controlled design (n = 60) was used with cycling (active, passive) and information (informed, not informed) as between-subjects factors. State anxiety, feelings of energy, and working memory (percent accuracy and reaction time for correct responses) were measured at baseline (time 1), immediately after cycling (time 2) and 20 minutes after cycling (time 3).

RESULTS

Most participants did not guess the purpose of the study (~92%) or expect a reduction in state anxiety (85%) or an increase in energy (80%) or cognitive performance (~93%). Mood and cognitive performance were not improved by active or passive cycling (all p values ≥ .12).

CONCLUSIONS

The methods used here to disguise the experimental hypotheses provide a potential framework for reducing demand characteristics and placebo responses in future investigations of psychological responses to exercise.

Challenges Establishing the Efficacy of Exercise as an Antidepressant Treatment: A Systematic Review and Meta-Analysis of Control Group Responses in Exercise Randomised Controlled Trials

BACKGROUND

Whilst previous meta-analyses have demonstrated that control group responses (CGRs) can negatively influence antidepressant efficacy, no such meta-analysis exists in exercise randomised controlled trials (RCTs).

OBJECTIVE

The aim of this study was to conduct a systematic review and meta-analysis investigating CGRs and predictors in control groups of exercise RCTs among adults with depression.

METHODS

Three authors acquired RCTs from a previous Cochrane review (2013) and conducted updated searches of major databases from January 2013 to August 2015. We included exercise RCTs that (1) involved adults with major depressive disorder (MDD) or depressive symptoms; (2) measured depressive symptoms pre- and post-intervention using a validated measure [e.g. Hamilton Depression Scale (HAM-D)]; and (3) included a non-active control group. A random effects meta-analysis calculating the standardised mean difference (SMD) together with 95 % confidence intervals (CIs) was employed to determine CGR.

RESULTS

Across 41 studies, 1122 adults with depression were included [mean (SD) age 50 (18) years, 63 % female]. A large CGR of improved depressive symptoms was evident across all studies (SMD -0.920, 95 % CI -1.11 to -0.729). CGRs were elevated across all subgroup analyses, including high quality studies (n = 11, SMD -1.430, 95 % CI -1.771 to -1.090) and MDD participants (n = 18, SMD -1.248, 95 % CI = -1.585 to -0.911). The CGR equated to an improvement of -7.5 points on the HAM-D (95 % CI -10.30 to -4.89). In MDD participants, increasing age moderated a smaller CGR, while the percentage of drop-outs, baseline depressive symptoms and a longer control group duration moderated a larger CGR (i.e. improvement) (p < 0.05).

CONCLUSION

In order to demonstrate effectiveness, exercise has to overcome a powerful CGR of approximately double that reported for antidepressant RCTS.

Effects of Yoga on Heart Rate Variability and Depressive Symptoms in Women: A Randomized Controlled Trial

OBJECTIVES

The purpose of the study was to investigate the effects of a 12-week yoga program on heart rate variability (HRV) and depressive symptoms in depressed women.

METHODS

This was a randomized controlled trial. Twenty-six sedentary women scoring ≥14 on the Beck Depression Inventory-II were randomized to either the yoga or the control group. The yoga group completed a 12-week yoga program, which took place twice a week for 60 min per session and consisted of breathing exercises, yoga pose practice, and supine meditation/relaxation. The control group was instructed not to engage in any yoga practice and to maintain their usual level of physical activity during the course of the study. Participants' HRV, depressive symptoms, and perceived stress were assessed at baseline and post-test.

RESULTS

The yoga group had a significant increase in high-frequency HRV and decreases in low-frequency HRV and low frequency/high frequency ratio after the intervention. The yoga group also reported significantly reduced depressive symptoms and perceived stress. No change was found in the control group.

CONCLUSIONS

A 12-week yoga program was effective in increasing parasympathetic tone and reducing depressive symptoms and perceived stress in women with elevated depressive symptoms. Regular yoga practice may be recommended for women to cope with their depressive symptoms and stress and to improve their HRV.

The Effect of Acute Exercise on Affect and Arousal in Inpatient Mental Health Consumers

Acute exercise performed at a self-selected intensity improves affect and may improve long-term adherence. Similarly, in people with severe depression, acute aerobic exercise performed at self-selected intensity improves affect and arousal. However, the relationship between changes in affect and arousal and perceived exercise intensity in people with mental illness has not been evaluated. Affect and arousal were assessed immediately prior to, and immediately following, a group exercise program performed at a self-selected intensity in 40 inpatient mental health consumers who received a diagnosis of anxiety or bipolar or depressive disorders. Exercise intensity was assessed immediately after exercise. Postexercise affect was significantly improved for people with bipolar and depressive disorders but not for people with anxiety disorders. For the group as a whole, results showed a significant curvilinear relationship between ratings of perceived exertion and postexercise affect. These data will inform the development and delivery of future exercise interventions for inpatient mental health consumers.