Background: Long-term stretching of human skeletal muscles increases joint range of motion through altered stretch perception and decreased resistance to stretch. There is also some evidence that stretching induces changes in muscle morphology. However, research is limited and inconclusive. Objective: To examine the effect of static stretching training on muscle architecture (i.e., fascicle length and fascicle angle, muscle thickness and cross-sectional area) in healthy participants. Design: Systematic review and meta-analysis. Methods: PubMed Central, Web of Science, Scopus, and SPORTDiscus were searched. Randomized controlled trials and controlled trials without randomization were included. No restrictions on language or date of publication were applied. Risk of bias was assessed using Cochrane RoB2 and ROBINS-I tools. Subgroup analyses and random-effects meta-regressions were also performed using total stretching volume and intensity as covariates. Quality of evidence was determined by GRADE analysis. Results: From the 2946 records retrieved, 19 studies were included in the systematic review and meta-analysis (n = 467 participants). Risk of bias was low in 83.9% of all criteria. Confidence in cumulative evidence was high. Stretching training induces trivial increases in fascicle length at rest (SMD = 0.17; 95% CI 0.01–0.33; p = 0.042) and small increases in fascicle length during stretching (SMD = 0.39; 95% CI 0.05 to 0.74; p = 0.026). No increases were observed in fascicle angle or muscle thickness (p = 0.30 and p = 0.18, respectively). Subgroup analyses showed that fascicle length increased when high stretching volumes were used (p < 0.004), while no changes were found for low stretching volumes (p = 0.60; subgroup difference: p = 0.025). High stretching intensities induced fascicle length increases (p < 0.006), while low stretching intensities did not have an effect (p = 0.72; subgroup difference: p = 0.042). Also, high intensity stretching resulted in increased muscle thickness (p = 0.021). Meta-regression analyses showed that longitudinal fascicle growth was positively associated with stretching volume (p < 0.02) and intensity (p < 0.04). Conclusions: Static stretching training increases fascicle length at rest and during stretching in healthy participants. High, but not low, stretching volumes and intensities induce longitudinal fascicle growth, while high stretching intensities result in increased muscle thickness. Registration : PROSPERO, registration number: CRD42021289884. © 2023, The Author(s).

The literature on emotion regulation (ER) is vast and insightful, but little is known about the proactive regulation of positive emotions. Herein we coin the term emotion crafting (EC), which is defined as proactively aiming to strengthen one’s positive emotions through two sequential components: being aware of what can make one feel good (i.e., awareness component) and proactively engaging in behaviors to initiate, maintain, or increase positive emotions (i.e., action component). We present a self-report measure of EC [i.e., the Emotion Crafting Scale (ECS)] and provide details on its discriminant and concurrent validity. Data were collected among a sample of 326 Norwegian adults (49.7% female; Mage = 42.90 years, SD = 14.76) who were representative in terms of age (between 18 and 70), gender, and geographical location within Norway. Results yielded evidence for a 2-factor structure consisting of the components Awareness and Action, which related in an expected way to other measures of ER. Subsequent structural equation modeling showed that the awareness component related positively to indicators of well-being and negatively to internalizing symptoms via higher levels of EC action and positive affect, even after controlling for other measures of ER. These promising findings not only support favorable reliability and validity of the ECS, but also underscore the importance of examining proactive regulation of positive emotions as a potential predictor of mental health. Future research is needed to examine the etiological role of EC in individuals’ psychological functioning. © 2023, The Author(s).

Many studies have assessed students’ motivation through surveys, but only a few studies systematically investigated through students’ own words the reasons and aims of their achievement striving. In the present study, we rely on the Goal Complex Perspective (Sommet and Elliot in J Educ Psychol 109(8):1141–1162, 2017. https://doi.org/10.1037/edu0000199; Vansteenkiste et al. in Educ Psychol 49(3):153–174, 2014. https://doi.org/10.1080/00461520.2014.928598) to uncover qualitative differences in achievement motivation. Content analysis of 1303 statements made by 597 Greek secondary students revealed (i) more autonomous motivation than controlled motivation statements, (ii) spontaneously generated statements of mastery-learning and outcome goals but rarely of performance-normative goals, (iii) mastery-learning goals being coupled with both autonomous and controlled motivation, providing ecological support for the conceptualization of mastery goal complexes. Logistic regression analyses verified our classification, as students’ statements were predicted by corresponding types of motivation assessed by close, Likert-type questions. These findings, which align with the Goal Complex Perspective, are discussed in terms of the operational definition of autonomous and controlled motivation and achievement goals.

Although the association between interparental conflict and adolescent adjustment is well documented, the intervening mechanisms that explain this relationship are not fully understood. Guided by the spillover hypothesis and the self-determination theory, this study examined whether the associations among interparental conflict and adolescent depressive feelings and life satisfaction were explained by maternal autonomy support and, in turn, by adolescent need frustration. Participants were 925 Turkish adolescents (Mage = 16.08 years, SD = 0.31) and their mothers (Mage = 41.43, SD = 5.16). Results from path analysis showed that interparental conflict was related to lower maternal autonomy support, and in turn to higher adolescent need frustration. Greater need frustration, in turn, predicted higher adolescent depressive feelings and lower life satisfaction six months later. These findings suggested that conflictual parental relationships may predict adolescent adjustment through poor parenting and adolescent need frustration. The findings and related directions for future research are discussed in the context of self-determination theory and its role in advancing a process-oriented understanding of the familial and individual determinants of adolescent adjustment. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Research has shown that teachers’ autonomy support and provision of structure relate to students’ agentic and behavioral engagement. Moreover, agentic engagement elicits higher teacher autonomy support. In the present 5-week diary study, we investigated the dynamic nature of this interplay between teachers and students through their cross-assessment of students’ agentic and behavioral engagement. We also considered the week-to-week student-reported teacher autonomy support and provision of structure as well as two student personal characteristics — proactive personality and situational autonomous versus controlled motivation. Two hundred fifty-seven Turkish middle school students and their teachers from 13 classes participated in the study. Multilevel analyses showed that students’ week-to-week perceived autonomy support and initial level of autonomous motivation positively predicted week-to-week agentic engagement (teacher- and student-reported). Students’ week-to-week perceived structure positively predicted week-to-week agentic and behavioral engagement (student-, but not teacher-, reported). These findings indicate the interplay between students’ situational engagement and teachers’ situational motivating style (i.e., autonomy support and provision of structure). They also suggest greater predictive power for students’ situational motivation over the personal trait of proactive personality. © 2021 Taylor & Francis Group, LLC.