Physiologia, Volume 6, Issue 2 (June 2026) – 14 articles

Background/Objectives: The combined effects of aerobic exercise and normobaric hyperoxia exposure on skeletal muscle in diabetes mellitus (DM) remain unclear. This study investigated whether their combination influences skeletal muscle capillary and mitochondrial function in diabetic rats. Methods: Seven-week-old male Wistar rats were randomly assigned to the following five groups: control (CON), DM, DM with aerobic exercise (DMEx), DM with aerobic exercise under 30% oxygen exposure (DMEx30), and DM with aerobic exercise under 50% oxygen exposure (DMEx50). Aerobic exercise and normobaric hyperoxia exposure were performed simultaneously in the DMEx30 and DMEx50 groups. Results: Combined aerobic exercise and normobaric hyperoxia significantly improved both capillary density and succinate dehydrogenase (SDH) activity in the soleus muscle, which is predominantly composed of slow-twitch fibers, in diabetic rats. In contrast, the effects were more limited in predominantly fast-twitch muscles, including the extensor digitorum longus and plantaris muscles. Conclusions: Combined aerobic exercise and normobaric hyperoxia may induce beneficial skeletal muscle adaptations in diabetic rats, with more pronounced effects in the predominantly slow-twitch soleus muscle than in predominantly fast-twitch muscles. These findings suggest that muscle fiber-type composition may influence responsiveness to this intervention. This combined approach may contribute to the development of novel exercise-based interventions for DM. Full article

Background/Objectives: This study examined the effects of an eight-week plyometric training programme on jump biomechanics, field-based jump performance, and repeated-jump endurance in 13–14-year-old volleyball players, and explored training-induced changes. Methods: A pre–post controlled experimental design was used. Thirty male volleyball players aged 13–14 years were assigned to an experimental group (EG, n = 15) or a control group (CG, n = 15). The EG completed a structured plyometric programme three times per week for eight weeks in addition to regular volleyball training, whereas the CG continued usual practice. Biomechanical variables were assessed during the Repeated Countermovement Jump test using the BTS Bioengineering G-Walk inertial measurement system, together with field-based jump and repeated-jump endurance tests. Outcomes were analysed using two-way mixed ANOVA (Group × Time). Δ-based correlations were examined using Pearson and Spearman coefficients with false discovery rate correction. Results: Significant Group × Time interaction effects were found for all analysed RCMJ variables (all p < 0.001). Significant interaction effects were also observed for all field-based jump and repeated-jump endurance outcomes (all p ≤ 0.025). The EG showed greater improvements over time than the CG across the principal biomechanical, practical, and endurance-related indicators. Correlation analysis revealed strong associations among the principal RCMJ variables and selected links with field-based and endurance measures. Conclusions: A structured plyometric programme may improve jump biomechanics, jump performance, and repeated-jump endurance in adolescent volleyball players. These findings should be interpreted cautiously because of baseline differences, the modest sample size, and the IMU-derived nature of force- and power-related estimates. Full article

Background/Objectives: Metabolic syndrome (MetS) is a cluster of cardiometabolic risk factors that increases the risk for cardiovascular disease. Although gait impairments are documented in older adults with MetS, few studies have examined gait biomechanics or the potential for gait-related measures to differentiate metabolic syndrome status in young adults. This study examined whether gait biomechanics, functional gait performance, and muscle strength are associated with MetS risk factors in young adults, and whether these measures predict MetS classification. Methods: Twenty-four young adults meeting criteria for metabolic syndrome (MetS+) and 24 participants without MetS (MetS−) completed cardiometabolic assessments, gait analysis, functional gait testing, and lower extremity isometric strength testing. Multiple linear regression examined associations between gait velocity and MetS risk factors, and binary logistic regression assessed the ability of biomechanical, functional, and strength variables to differentiate MetS status. Results: Compared with matched controls, MetS+ participants demonstrated slower gait velocity, longer stance time, and lower propulsive ground reaction forces. Regression models examining MetS risk factors did not significantly explain variance in gait velocity. Logistic regression indicated that spatiotemporal gait parameters and GRF variables could differentiate MetS classification with fair predictive ability, whereas functional gait performance and strength measures showed limited classification performance. Conclusions: Young adults with MetS demonstrated modest differences in select gait variables, but the MetS risk factors did not show strong relationships with gait velocity in regression analyses. Spatiotemporal gait parameters differentiated MetS+ and MetS− groups but offered limited predictive value. These findings suggest that subtle biomechanical differences may be present early in the progression of MetS, although stronger functional impairments may not yet be detectable in young adults. Full article

Background: Childhood cancer survivors commonly experience long-term treatment effects that impair physical function. Access to in-person physical fitness assessments is often limited by geographic, logistical, and resource constraints. Virtually supervised physical fitness assessments may offer a feasible alternative; however, evidence in this population remains limited. Methods: This study evaluated the feasibility of delivering virtually supervised physical fitness assessments via videoconference for children and adolescents aged 5–18 years following completion of cancer treatment. Assessments evaluated lower-body strength (30 s sit-to-stand), upper-body strength (30 s push-up), mobility (timed up-and-go), balance (single-leg balance), aerobic endurance (two-minute step), and flexibility (sit-and-reach). Pre-defined feasibility benchmarks included recruitment (≥15 participants within three months), assessment completion (≥85% of participants completing all six assessments), individual assessment completion (≥90% of planned assessments completed), technique fidelity (≥85% of assessments performed with correct technique), session duration (≥90% of sessions completed in ≤30 min), safety (no adverse events), and participant satisfaction (qualitative feedback). Results: Twenty-nine participants were enrolled, with 28 completing the virtual assessments. The sample (61% male) had a mean age of 9.8 ± 3.7 years (range 5–16), with acute lymphoblastic leukaemia the most common diagnosis (46%). Recruitment exceeded benchmarks (23 participants within three months). Assessment completion was 92.9% (26/28), individual assessment completion was 98.8% (166/168), and technique fidelity was 90.9%, with the lowest fidelity for push-ups (73.1%). Most sessions were completed within 30 min (92.9%; median 19.5 min, range 15–33). No adverse events occurred. Feedback indicated high satisfaction, highlighting convenience, engagement, and practicality. Conclusions: Virtually supervised physical fitness assessments were feasible, safe, and acceptable for childhood cancer survivors. These findings provide initial feasibility evidence to support further validation and implementation research before broader clinical application. Full article

The purpose of this narrative review was to describe the maximal strength, muscle power, rate of force development, and muscle morphology of athletes across different ski disciplines. Specifically, this review synthesizes evidence on upper- and lower-body maximal strength both dynamically and isometrically, muscle power through jumping performance and rate of force development, and muscle morphology in competitive skiers. Furthermore, it examines how these neuromuscular parameters adapt when resistance-training interventions are incorporated into athletes’ routine training programs. Following a literature search, 30 studies met the inclusion criteria, 18 describing the ski athletes’ characteristics mentioned above and 12 evaluating the effects of resistance-training interventions. Altogether, these studies involved 561 participants, with ages ranging between 14.6 ± 1.1 years and 35 years. Overall, the above characteristics of ski athletes appear to align with sport-specific demands, which vary across ski disciplines. The resistance-training protocols applied in this population are predominantly high-load resistance training and it appears that resistance training may benefit from increased emphasis in ski-specific preparation. However, training programs tailored to the specific demands of each discipline are recommended. Full article

Objective: Analyze physical fitness variables and body composition to define patterns or similarities in performance using principal component analysis. Materials and Methods: Sixty-eight players participated in the study, divided into three groups according to their age: Under-13 (n = 23), Under-15 (n = 27) and Under-17 (n = 18). A comparative cross-sectional study was performed. The variables analyzed were squat jump, countermovement jump, countermovement jump with arms, hamstring strength, COD-Timer 5-0-5, COD-Timer 5 + 5, speed (5, 10, 15 m), and running anaerobic sprint test. Body composition variables were skinfold thickness, diameters, and circumferences. Results: For the squat jump, 10.4% of the variability in speed (η² = 0.104) and 12.5% of the variability in jump height (η² = 0.125) are explained by category, both with moderate effect sizes. For the countermovement jump, 10.8% of the variability in speed (η² = 0.108) and 13.2% of the variability in jump height (η² = 0.132) are explained by category, both with moderate effects. For the running anaerobic sprint test power test, a large effect size was determined for each of the six times, indicating that at least 57.4% of the variability in time is explained by category. Conclusions: Two control groups were identified according to category (Under-13, Under-15, Under-17), revealing that principal component 1 and principal component 2 were significant in the performance of anthropometric variables such as residual mass, bi-styloid diameter, arm span, and residual mass, and physical variables, specifically related to COD-Timer 5 + 5, COD-Timer 5-0-5, and speed. Full article

Background/Objectives: This systematic review examined whether oral vitamin D supplementation improves vitamin D status, health, and exercise outcomes in indoor-training aquatic athletes. Methods: We systematically reviewed randomized, placebo-controlled trials (>2 weeks) investigating vitamin D supplementation in competitive swimmers and divers. Six eligible trials (n = 246) were included and summarized descriptively. Results: Supplementation (2000–5000 IU/day for 12 weeks to 6 months) consistently increased serum 25(OH)D compared with placebo, with average increases up to 9.3 ng/mL. While higher doses occasionally improved muscle strength and lean mass, evidence showed no consistent benefits for swimming performance, immune function, or bone turnover. Additionally, higher body mass index (BMI) correlated with smaller 25(OH)D increases. Conclusions: Vitamin D effectively corrects deficiencies in aquatic athletes but lacks consistent ergogenic benefits. Therefore, in practice, supplementation should serve primarily as a targeted corrective measure for deficiency to support fundamental musculoskeletal health, rather than a generalized strategy for performance enhancement. Full article

Background/Objectives: To develop and internally validate multiple linear regression models to predict estimated VO2max from anthropometric variables and easily obtainable physical fitness tests in active university students and to compare model performance when estimated VO2max was derived from the Rockport Walk Test versus the 20-m Shuttle Run (Course Navette). Methods: Anthropometric variables and physical fitness indicators, including body mass index (BMI), Ruffier index, and burpee repetitions, as well as sex and age, were evaluated. Estimated VO2max was obtained separately from the Rockport Walk Test and the 20-m Shuttle Run using their respective field test equations. For each test, a multiple linear regression model was fitted using the same set of predictors. Model performance was assessed using apparent metrics and internal validation with optimism correction based on repeated cross-validation. Results: The Rockport walk test model showed better predictive performance, explaining 55.2% of the variability in estimated VO2max (R² = 0.552; adjusted R² = 0.498) with a lower prediction error (RMSE = 3.54 mL·kg⁻¹·min⁻¹). In contrast, the 20-m shuttle run model showed lower explanatory capacity (R² = 0.319; adjusted R² = 0.256) and a substantially higher prediction error (RMSE = 11.93 mL·kg⁻¹·min⁻¹). Internal validation reduced performance in both models, more markedly in the 20-m shuttle run, where the corrected R² fell to 0.163 and the corrected RMSE increased to 13.18 mL·kg⁻¹·min⁻¹, compared with 0.338 and 4.37 mL·kg⁻¹·min⁻¹ in the Rockport walk test. Conclusions: Estimated VO2max can be predicted pragmatically using low-cost models based on simple variables in a university setting; however, model performance depends on the field test used. The Rockport walk test appears more suitable for prediction using general-purpose predictors, whereas the 20-m shuttle run may require more test-specific predictors and external validation before application beyond the development sample. Full article

Background: The number of people working in Antarctica has steadily increased. Identifying the characteristic functional changes in polar expeditioners can help preserve health, enhance work capacity, and improve adaptive potential in specific environments. Objective: This study aimed to evaluate the impact of a short-term (30-day) expedition in Antarctica on selected physiological parameters among expedition participants, depending on their body mass index (BMI). Methods: Thirty-four expedition members, divided into 3 BMI groups, were examined before and after a one-month stay in Antarctica. The assessments included anthropometry, body composition analysis, blood pressure (BP) evaluation, and a cycle ergometer stress test, performed up to 85% of predicted maximal heart rate (PWC85%) with gas analyses and heart rate measured at the 3rd minute after exercise completion (HR3’), used as an indicator of cardiovascular recovery. Results: After the expedition, the participants with normal weight showed a modest but significant increase in body weight and BMI, and non-significant increases in fat mass (FM) and muscle mass (MM); cardiovascular recovery and physical working capacity were improved, while aerobic fitness remained unchanged. In the overweight group, post-expedition body weight and BMI did not change significantly, although small reductions in FM and improvements in MM, BP, PWC85%, and HR3’ were observed. Returning, the participants with obesity demonstrated non-significant improvements in body composition and modest declines in BP, together with a significant improvement in HR3’. Conclusions: Comparative analysis revealed significant differences in post-expedition changes in several functional parameters between the normal-weight and obese groups. Overall, the Antarctic expedition elicited beneficial cardiovascular and functional adaptations, particularly among overweight individuals, while body composition and aerobic capacity remained unchanged across all groups. Full article

Background: Contemporary aneurysm surgery increasingly requires the management of complex lesions with limited physiological reserve. A growing “physiology-first” paradigm emphasizes that optimizing cerebrovascular dynamics during aneurysm treatment is essential for favorable neurological outcomes. Methods: This narrative review synthesizes current evidence and expert perspectives on cerebrovascular physiology relevant to aneurysm surgery, including cerebral perfusion, autoregulation, ischemia tolerance, neuroprotection, and intraoperative monitoring. Results: Key themes include individualized blood pressure management, recognition of impaired autoregulation—particularly after subarachnoid hemorrhage—safe application of temporary arterial occlusion, and the use of multimodal neuromonitoring to detect ischemia in real time. The strengths and limitations of neuroprotective adjuncts are critically discussed in the context of available clinical evidence. Conclusions: Integrating cerebrovascular physiology into aneurysm surgery supports informed intraoperative decision-making, minimizes ischemic injury, and enhances patient outcomes. A physiology-first approach complements technical expertise and represents a cornerstone of modern neurovascular practice. Full article

Background: As Para-Powerlifting (PP) athletes need the maximum bench press concentric strength performance during competitions, the velocity of the eccentric phase could be critical to the sport’s success. Methods: Through eccentric tempo modification, normative, faster, and slower bench press eccentric velocities were tested on 16 experienced PP athletes. Mean propulsive velocity (MPV), maximum velocity (Vmax), and power were measured during a single bench press set at different loads (90% and 100% of 1RM) and tempos. After the bench press set, Maximal isometric force (MIF), rate of force development (RFD), impulse, variability, and maximal average force (MAF) were obtained through an isometric bench press test. Results: Slower and faster tempos were not different in concentric performance than a normative tempo at the 90% 1RM load. A faster tempo generated higher MPV and Vmax than a normative one at the 100% 1RM load. A normative tempo produced higher MIF than a slower tempo, and higher impulse than a faster tempo after a 90% 1RM bench press set. Conclusions: PP athletes seem to have an optimized technique in submaximal loads; however, they may need faster eccentric velocities in the 100% 1RM load to improve their concentric performance. Full article

Excess post-exercise oxygen consumption (EPOC) reflects cardiorespiratory fitness, energy metabolism and the residual physiological effects of preceding exercise. We aimed to compare EPOC profiles of master swimmers across different age groups and performance levels. Fourteen male master swimmers performed a 200 m all-out front crawl and breath-by-breath gas exchange and their heart rates were recorded during exercise and for 5 min post-exercise. A single exponential regression model was fitted to the post-exercise oxygen uptake kinetics to determine the EPOC amplitude, time constant and time delay. The EPOC magnitude was calculated as the area under the oxygen uptake–time curve. Swimmers were grouped into younger vs. older and faster vs. slower clusters using the 50th percentile, and the associations between age, performance and physiological variables were examined. Older swimmers were slower and showed a lower peak oxygen uptake than their younger counterparts (213.9 ± 27.9 vs. 165.7 ± 24.9 s and 39.1 ± 4.8 vs. 50.2 ± 8.1 mL∙kg⁻¹∙min⁻¹; p < 0.05). Slower swimmers were older and displayed a lower EPOC amplitude than faster performers (69.8 ± 7.3 vs. 45.7 ± 1.7 years and 23.2 ± 4.0 vs. 36.8 ± 10.2 mL∙kg⁻¹∙min⁻¹; p < 0.05). Although many of the variables did not differ between groups, effect sizes were moderate to very large (except for time constant and time delay). The swimmers’ age related directly to their performance and inversely to their peak oxygen uptake, peak heart rate and EPOC amplitude, while performance presented inverse associations with peak oxygen uptake, peak heart rate, EPOC amplitude and EPOC magnitude (p < 0.05). Master swimmers of different ages and performance levels exhibited distinct EPOC characteristics, which may provide relevant information regarding the individualisation of training and recovery strategies in this population. Full article

Objectives: The study aimed to comprehensively assess the impact of tattoos on the structural and functional properties of the skin in healthy women. Methods: The investigation included 22 female participants aged 19–41 years, covering a total of 88 tattoos. Various diagnostic tools were employed: a Tewameter TM300 to evaluate transepidermal water loss (TEWL), a Corneometer and Cutometer to measure skin hydration, elasticity, and firmness, and high-frequency ultrasonography (HFUS) to assess epidermal thickness and skin echogenicity. The results showed that the presence of tattoos did not significantly influence TEWL values. Although regional differences in TEWL were observed in non-tattooed skin, tattooed skin showed no such variability, suggesting a consistent barrier function regardless of tattoo location. Corneometric and cutometric assessments revealed no significant differences in hydration, elasticity, or firmness between tattooed and non-tattooed skin. These parameters were also not influenced by tattoo age, although a physiological decline in mechanical skin properties was observed with increasing participant age. HFUS indicated a significantly thinner epidermis in tattooed areas compared to their non-tattooed counterparts. Additionally, tattooed skin demonstrated a higher percentage of low-echogenicity pixels in the lower dermis, suggesting localized structural changes. However, neither the age of the tattoo nor the age of the participant significantly affected the ultrasound parameters. Conclusions: Tattoos did not impair key skin functions such as hydration, elasticity, or barrier integrity, but were associated with structural changes observable via high-frequency ultrasonography. Full article

Menopause is a natural biological transition marked by the cessation of regular menstrual cycles and is associated with significant endocrine, hormonal, and metabolic changes. Sleep disturbances are among the most common and distressing symptoms during this period, affecting approximately 40–60% of women in the menopausal transition and postmenopause. Vasomotor symptoms, including hot flushes and night sweats, often occur alongside fatigue, anxiety, and mood disturbances. These symptoms frequently coexist with sleep disorders such as insomnia, early morning awakenings, fragmented sleep, obstructive sleep apnea, restless legs syndrome, and circadian rhythm disruptions. Evidence from animal models, translational research, and clinical studies highlights the complex interaction between hormonal fluctuations, neuroendocrine dysregulation, metabolic changes, and circadian rhythm disruption. These factors contribute to altered sleep regulation, appetite control, and weight gain during the menopausal transition. This review summarizes current evidence on the mechanisms of underlying sleep disturbances in menopause, their clinical manifestations, diagnostic approaches, and available therapeutic strategies. Improving the management of sleep disorders during this stage may substantially enhance overall health and quality of life in menopausal women. We discuss presentation of different sleep disorders in menopause, their current management and future direction of research for development of precision-based algorithm of treatment considering the endocrine and hormonal profile of the women. Full article