International Journal of Physical Education, Fitness and Sports

Characterizing the Physiological Demands & Serum Cortisol Levels of Thru-Hiking the Continental Divide Trail

Hennekens M — 2025-07-04

The popularity of thru-hiking is expanding within the outdoor recreation industry, drawing attention to the physiological demands of prolonged endurance activities in natural environments. This study examined the effects of a long-distance thru-hike on circadian rhythm regulation, body composition, and physical fitness parameters in two adult subjects who undertook the Continental Divide Trail in 2021. Serum cortisol concentrations were measured in the morning and evening at four time points: pre-hike, mid-hike, post-hike, and 16 weeks post-hike. Physical fitness testing included assessments of body composition, maximal oxygen uptake, and muscular endurance were conducted at pre-hike, post-hike, and 16 weeks post-hike. Both subjects demonstrated significant physiological adaptations, including changes in evening serum cortisol concentrations and alterations in adipose tissue and muscle mass. The female subject showed marked improvements in lower body muscular endurance and maximal oxygen uptake, while the male subject experienced reductions in muscle mass and muscular endurance, while maintaining aerobic capacity. These findings suggest that thru-hiking may influence endocrine function and physical fitness dependent on initial fitness status and individual physiological characteristics. This study highlights the need for further research to better characterize the health impacts of thru-hiking.

Assessing the Effect of High Intensity Interval Training and Fast Continuous Training on Resting Heart Rate and VO2 Max of Adult Athletes

Manish Acharjee — 2025-09-23

Background: Cardiovascular fitness, measured through Resting Heart Rate (RHR) and Maximal Oxygen Uptake (VO₂ Max), is critical for optimizing athletic performance. High-Intensity Interval Training (HIIT) and Fast Continuous Training (FCT) are two aerobic conditioning modalities widely used to improve cardiovascular efficiency, but their comparative effects remain insufficiently studied in adult competitive athletes. Aim: This study aimed to compare the effects of an 8-week HIIT and FCT program on RHR and VO₂ Max in adult athletes, thereby evaluating the efficacy of each training modality in enhancing aerobic performance. Methods: A randomized controlled trial design was employed involving 90 adult athletes (45 males and 45 females, aged 21-26), randomly located into three groups: HIIT (n=30), FCT (n=30), and Control (n=30). RHR and VO₂Max were assessed during pre- and post-intervention using Polar H10 monitors and Vmax Encore Metabolic Cart, respectively. Data were analysed using ANCOVA (Analysis of Covariance) to control for pre-test differences, followed by Tukey’s post-hoc comparison. Results: Post-intervention results revealed statistically significant improvements in both RHR and VO₂ Max across the training groups (p < 0.05). The HIIT group exhibited the most significant reduction in RHR (62.72 bpm) and the highest increase in VO₂ Max (52.12 ml/kg/min), outperforming both FCT (RHR = 65.06 bpm; VO₂ Max = 49.40 ml/kg/min) and the Control group (RHR = 70.32 bpm; VO₂Max = 41.28 ml/kg/min). Effect sizes were large for both RHR (η² = 0.950) and VO₂ Max (η² = 0.982), indicating robust model fit. Conclusion: The findings confirm that both HIIT and FCT are effective in improving cardiovascular parameters among adult athletes, with HIIT demonstrating superior efficacy in a shorter duration. These results support the strategic incorporation of HIIT in training regimens aimed at maximizing aerobic performance and cardiovascular health.

Acute Effects of Knowledge of Results on Repeated Sprint Ability in Adolescent Male Team Sports Athletes

Morris J — 2025-09-29

Repeated-sprint ability is critical for sustaining performance in team sports. Augmented feedback, particularly knowledge of results, may enhance athletic performance. However, its effects on repeated-sprint ability in young athletes remain underexplored. This study aimed to evaluate the impact of knowledge of results on repeated-sprint ability among adolescent male team sport athletes. A randomised crossover design was employed with 13 participants (age = 15 ± 1 years; height = 1.74 ± 0.07 meters; body mass = 61.0 ± 8.4 kilograms) completing linear sprints, shuttle sprints, and change of direction sprints to assess initial sprint time, average sprint time, total sprint time, and percentage decrement score. Data were analysed using repeated measures analysis of variance. The results indicated no significant interactions for initial sprint time (p = 0.503), average sprint time (p = 0.639), total sprint time (p = 0.635), or percentage decrement score (p = 0.600) across feedback conditions. In conclusion, providing knowledge of results in the form of sprint times did not enhance performance or mitigate fatigue in junior athletes during repeated-sprint ability protocols. Coaches should consider alternative strategies to enhance athlete performance during training and competition.

Combined Exercise Methods in Resistance Training: A Brief Review of Acute Responses and Long-Term Adaptations

Diogo Cardozo — 2025-07-02

The purpose of this article was to review and synthesize the scientific literature on the acute effects and long-term adaptations of combined exercise methods (CEM) compared to traditional strength training (TST), with a focus on performance outcomes, physiological responses, strength gains, and muscle hypertrophy. A literature search was conducted in the PubMed, BIREME/BVS, and Google Scholar databases using the following search terms: ‘strength training’ OR ‘resistance training’ AND ‘paired-set’ OR ‘bi-set’ OR ‘tri-set’ OR ‘superset’ OR ‘agonist-antagonist’, in various combinations with the Boolean operators “OR” and “AND”. Studies published in English that compared the effects of combined exercise training with traditional resistance training, evaluated acute physiological or performance-related responses, and investigated adaptations following a training period were included in this review. A total of 49 studies were included in this review, comprising 40 acute studies and 9 longitudinal studies. These studies evaluated metabolic and hormonal responses, electromyographic activity, performance outcomes, strength gains, and muscle hypertrophy. Overall, the findings suggest that CEM produce similar or, in some cases, superior responses compared to TST across several parameters. Thus, such methods represent a valuable alternative for athletes and individuals with limited time availability, as they can still promote significant training adaptations.