Background: Childhood and adolescence represent critical developmental periods characterized by rapid somatic growth, endocrine changes, and the progressive attainment of biological maturity. These maturational processes substantially influence the development of physical fitness, yet are often overlooked when evaluating performance in youth populations. This structured narrative review aims to synthesize current knowledge regarding the relationships between somatic growth, biological maturity, and physical fitness in children and adolescents. Methods: A structured narrative review was conducted by systematically searching PubMed, Scopus, and Web of Science databases for peer-reviewed articles published up to February 2026. Keywords included ‘biological maturation’, ‘physical fitness’, ‘youth’, ‘adolescence’, ‘peak height velocity’, and ‘bio-banding’. Studies were eligible if they examined relationships between biological maturity indicators and physical fitness outcomes in children and adolescents aged 8–19 years. No publication date restrictions were applied, although priority was given to articles from the past 15 years. Results: Evidence consistently indicates that biological maturity substantially influences muscular strength, power, and speed in males; findings among females and for cardiorespiratory fitness are more nuanced and context-dependent. Early-maturing boys typically exhibit superior strength and power performances, whereas findings among girls are more variable. Earlier maturation in girls is frequently associated with increased adiposity, which may attenuate performance in weight-bearing activities. When maturity status is ignored, physical fitness evaluations may misrepresent the capabilities of late-maturing youth and potentially discourage long-term participation in physical activity. Conclusions: Integrating biological maturity into youth fitness evaluation frameworks is essential for accurately interpreting performance data and for providing developmentally appropriate interventions. Three implementation strategies are recommended: (i) adoption of maturity offset or percentage of predicted adult stature as standard covariates; (ii) development of maturity-stratified normative standards; and (iii) implementation of bio-banding in youth sport development.

Background and Objectives: Handgrip strength represents a critical indicator of physical fitness and nutritional status in adolescents, yet population-specific reference values remain limited in developing countries. Understanding age- and sex-specific variations is crucial for accurate clinical assessment and effective health monitoring. The objective of this study was to establish comprehensive reference values for handgrip strength in healthy Tunisian adolescents aged 13–19 years and examine sex and age group differences in these measures. Materials and Methods: This cross-sectional study was conducted between September 2024 and June 2025, involving a sample of 950 participants (482 males, 468 females) aged 13–19 years from northwest Tunisia. Handgrip strength was measured using standardized dynamometry protocols for both hands. Anthropometric measurements included height, weight, and body mass index. Percentile curves were generated using the LMS method, and correlations between handgrip strength and anthropometric variables were analyzed using Pearson correlation coefficients. Results: Males demonstrated significantly higher handgrip strength than females from age 13 onward (13 years: p = 0.021; 14–19 years: p ≤ 0.001). Effect sizes for sex differences were consistently large across age groups (Cohen’s d range: 0.53–2.09 for the dominant hand). Mean dominant handgrip strength ranged from 25.60 ± 7.73 kg to 47.60 ± 12.45 kg in males and 21.90 ± 6.13 kg to 28.40 ± 4.74 kg in females across age groups. After adjusting for body mass, sex differences remained significant between groups (13 years: p = 0.014; d= 1.5; 14–19 years: p ≤ 0.001; d: 1.71–3.12). Strong positive correlations emerged between handgrip strength and height (males: r = 0.748, females: r = 0.601), body mass (males: r = 0.659, females: r = 0.601), and body mass index (BMI) (males: r = 0.391, females: r = 0.461). Body mass and height emerged as the strongest predictors of handgrip strength in both sexes, while BMI showed a smaller but still significant contribution. Conclusions: This study provides the first comprehensive age- and sex-specific reference values for handgrip strength in Tunisian adolescents. Healthcare providers can utilize these percentile charts for the clinical assessment and identification of musculoskeletal fitness deficits. The results suggest its use in educational and clinical contexts.

This study adapted and validated the How I Think Questionnaire (HIT-Q), intending to develop an Arabic version of the measure. The study assessed the (a) factorial structure of the Arabic version of the How I Think Questionnaire (A-HIT-Q), (b) construct validity evidence of the A-HIT-Q based on the internal structure of the scale, and (c) criterion validity evidence, highlighting how the cognitive distortions measure relates to some key theoretical variables such as depression. This study involved 762 Tunisian students aged 15–22 years, using a non-probabilistic sampling method. The students were boys (n = 297) and girls (n = 465). They completed self-report forms on Arabic-HIT-Q, depression (HADS), sleep (ISI), and physical activity participation, adhering to all relevant ethical considerations. Exploratory analysis revealed four factors which accounted for 73.46% of the variations in the distortion measure. Reliability analysis showed good internal consistency (α = 0.915) and temporal stability (r = 0.879). Criterion validity evidence showed cognitive distortion (as measured with the A-HIT-Q) was significantly associated with physical activity participation, anxiety, depression, and insomnia. However, no significant relationship has been observed between cognitive distortion, age, gender, and study levels. The evidence gathered supports the utility of the A-HIT-Q. Thus, the instrument demonstrates high efficacy in assessing the levels of cognitive distortions among adolescent students residing in Arabic-speaking regions.

Background: Young adults face a convergence of academic, economic, and social pressures that elevates their risk for stress-related psychological disorders. Perceived stress encompasses two theoretically and empirically distinct components, perceived helplessness and perceived self-efficacy, but most research treats it as a single composite score, obscuring the differential mechanisms through which each dimension influences mental health. Aim: The study aimed to (i) quantify the direct effects of perceived helplessness and perceived self-efficacy on psychological distress, (ii) test insomnia and physical activity as concurrent mediators of each dimension’s indirect pathway to distress, and (iii) determine whether the two stress dimensions activate meaningfully distinct mechanisms. Methods: A cross-sectional study enrolled 1688 young adults aged 18–23 years (M = 18.76, SD = 1.01; 41.6% female) from higher education institutions in Tunisia. Participants completed Arabic-validated versions of the Perceived Stress Scale (PSS-10), Insomnia Severity Index (ISI), Depression Anxiety Stress Scales (DASS-21), and the International Physical Activity Questionnaire (IPAQ). Structural equation modeling (SEM) with unweighted least squares estimation and 5000 bootstrap resamples tested direct and indirect pathways. Results: Perceived helplessness exerted strong direct effects on psychological distress (beta = 0.25, p < 0.001) and substantial indirect effects through insomnia (beta = 0.21, p < 0.001) and physical activity (beta = 0.03, p < 0.001). Insomnia was the dominant mediator, showing the strongest bivariate association with distress (r = 0.58, p < 0.01). Perceived self-efficacy produced markedly weaker direct (beta = 0.06, p = 0.002) and indirect effects, a pattern that, like its other associations in the model, runs in the same positive direction as perceived helplessness rather than the inverse direction conventionally expected of a protective factor. Model fit was acceptable (CFI = 0.994, SRMR = 0.018, RMSEA = 0.076, the latter below the conventional 0.08 threshold). Conclusions: Stress management deficits are associated with psychological distress primarily through sleep disruption, consistent with a mediating role for insomnia in this cross-sectional sample. Physical activity provides a meaningful but secondary protective correlate. These findings offer a preliminary, hypothesis-generating basis for stratified, mechanism-based mental health interventions targeting sleep regulation and stress management in young adult populations, pending prospective confirmation.