Qubahan Journal of Coaching and Sports Sciences
Qubahan Journal of Coaching and Sports Sciences (QJCS), ISSN: 3078-2953, is a quarterly academic journal published by Qubahan. QJCS publishes original research in the fields of physical therapy, sports therapy and rehabilitation, general social sciences, general health professions, visual arts, and performing arts. QJCS is a peer-reviewed open-access journal. QJCS provides immediate, worldwide, barrier-free access to the full text of research articles without requiring a journal subscription.
Effects of High-Intensity Interval Training on Running Economy, Lactate Threshold, and Time-to-Exhaustion in Trained Distance Runners
This study examined whether replacing a modest portion of habitual endurance running with structured high-intensity interval training (HIIT) improves running economy, lactate-threshold velocity, and time-to-exhaustion in trained male distance runners. Twenty-eight trained male runners were randomized to HIIT (n = 14) or to a control group (n = 14) for 8 weeks. The HIIT group completed two supervised weekly sessions, progressing from 4 x 3 min to 6 x 3 min at 90-95% of VO2max velocity, separated by 2-min active recoveries, while reducing easy mileage to keep weekly training time comparable with the control group. The control group maintained habitual endurance training. Running economy at 12 and 14 km/h, blood lactate during submaximal running, velocity at 4 mmol·L-1 blood lactate, VO2max, velocity at VO2max, time-to-exhaustion at velocity at VO2max, and 5-km time-trial performance were measured before and after training. Group-by-time effects were assessed using mixed repeated-measures analysis of variance, with significance set at p < 0.05. HIIT produced greater improvements than control in running economy at 14 km/h (-3.8% vs -0.6%, p < 0.001), velocity at 4 mmol·L-1 lactate (+4.2% vs +1.1%, p < 0.001), time-to-exhaustion (+15.8% vs +2.8%, p < 0.001), and 5-km time-trial time (-2.6% vs -0.6%, p = 0.002). VO2max improved modestly after HIIT (+2.6% vs +0.8%, p = 0.027). A carefully dosed HIIT substitution block improved linked determinants of endurance performance without increasing total weekly training time. The findings support HIIT as a targeted redistribution strategy in trained male runners rather than as an indiscriminate addition of hard training.
Copyright (c) 2022 Qubahan Techno Journal https://creativecommons.org/licenses/by-nc-nd/4.0
Influence of Coach Communication Style on Anxiety, Confidence, and Match Performance in Amateur Athletes
Coach communication is one of the most direct ways in which athletes interpret competitive demands, understand tactical roles, and regulate emotion before and during competition. This study examined whether perceived coach communication style was associated with competitive anxiety, self-confidence, and match performance in amateur male and female athletes. A cross-sectional field design was used with 236 amateur athletes from team and individual sports. Athletes completed pre-match measures of supportive and controlling coach communication, cognitive anxiety, somatic anxiety, and self-confidence. Match performance was assessed after the competition using a standardized 0-100 index that combined coach ratings and sport-specific match indicators. Athletes were categorized by their dominant perceived communication style: supportive, neutral, or controlling. Group differences were tested with one-way analysis of variance, adjusted associations were examined using multiple linear regression, and the indirect role of self-confidence was tested with bootstrapped mediation. Supportive communication was associated with lower cognitive anxiety (M = 13.32 ± 2.75), lower somatic anxiety (M = 12.96 ± 2.61), higher self-confidence (M = 16.18 ± 2.37), and higher match performance (M = 78.83 ± 8.74) than neutral and controlling communication. Group effects were statistically significant for cognitive anxiety, somatic anxiety, self-confidence, and performance (all p < 0.001), with moderate effect sizes rather than very large differences. In adjusted regression, supportive communication modestly predicted self-confidence and performance, whereas controlling communication modestly predicted anxiety and negatively predicted confidence and performance. Self-confidence partially mediated the association between supportive communication and performance. The findings indicate that the coach's communication style is meaningfully related to the psychological and performance profiles of amateur athletes, with supportive communication showing the most favorable pattern and controlling communication showing the least favorable pattern.
Copyright (c) 2025 Qubahan Techno Journal https://creativecommons.org/licenses/by-nc-nd/4.0
Dose-Response Association Between Weekly Exercise Volume and Health-Related Fitness in Early Adulthood
Weekly exercise volume is a central component of public health guidance, yet the shape of its association with health-related fitness in early adulthood remains important for universities, workplaces, and community programs that seek realistic targets for young adults. This field study examined the dose-response association between weekly moderate-to-vigorous exercise volume and health-related fitness in women and men aged 18-30 years. A mixed-sex sample of 480 adults (240 women and 240 men; mean age 24.3 +/- 3.6 years) completed a seven-day exercise log supported by wearable summaries when available, followed by field assessments of cardiorespiratory fitness, muscular strength and endurance, body composition, resting heart rate, and blood pressure. Exercise volume was grouped as <75, 75-149, 150-299, 300-449, and >=450 min/week, and continuous associations were examined using adjusted linear regression and restricted cubic spline models. Statistical significance was set at p < 0.05. Health-related fitness improved in a graded pattern across exercise-volume categories. The adjusted fitness composite increased from 47.8 +/- 8.6 points in the <75 min/week group to 66.3 +/- 8.6 points in the >=450 min/week group, with the largest gains observed between the lowest-volume group and adults meeting 150-299 min/week. Each additional 60 min/week of exercise was associated with higher fitness composite score (beta = 1.34, 95% CI: 0.92 to 1.76, p < 0.001), higher predicted VO2max (beta = 0.81 ml/kg/min, 95% CI: 0.54 to 1.08, p < 0.001), lower waist circumference (beta = -0.42 cm, p < 0.001), lower resting heart rate (beta = -0.75 beats/min, p < 0.001) and lower systolic blood pressure (beta = -0.38 mmHg, p = 0.002). Spline analysis indicated a curvilinear relationship, with rapid improvement up to approximately 300 min/week and smaller additional gains thereafter. Associations were similar in women and men. These findings support a practical dose-response interpretation: moving inactive young adults toward guideline-level exercise yields the greatest fitness gains. At the same time, higher volumes remain beneficial but show diminishing incremental returns.
Copyright (c) 2024 Qubahan Techno Journal https://creativecommons.org/licenses/by-nc-nd/4.0
Impact of Positive Coaching Strategies on Self-Efficacy and Competitive Performance in School-Aged Athletes
Positive coaching strategies are widely recommended in youth sport, yet their effects on psychological confidence and competitive performance require field-based evidence with measurable outcomes. This controlled 10-week study examined the impact of positive coaching strategies on athletic self-efficacy and competitive performance in school-aged athletes. A mixed-sex sample of 224 athletes (112 female and 112 male; age 13.9 +/- 1.2 years) from school and community sport programs was randomly assigned to a positive coaching strategy condition or a standard coaching comparison condition. The positive coaching program trained coaches to use specific praise, effort-focused feedback, autonomy-supportive questioning, mistake-contingent encouragement, and task-focused corrective instruction. Outcomes included athletic self-efficacy, competitive performance composite, skill execution, tactical decision-making, intrinsic motivation, competitive anxiety, and attendance. Statistical significance was set at p < 0.05. Compared with standard coaching, positive coaching produced larger gains in self-efficacy (adjusted group-by-time effect = 0.72, 95% CI: 0.49 to 0.95, p < 0.001) and competitive performance (adjusted effect = 4.31 points, 95% CI: 2.19 to 6.43, p < 0.001). Positive coaching also improved skill execution, tactical decision-making, intrinsic motivation, and attendance, and reduced competitive anxiety. Effects were similar in female and male athletes. Regression and mediation analyses showed that changes in self-efficacy predicted performance improvement and partially mediated the relationship between coaching and performance. These findings suggest that positive coaching can strengthen young athletes' confidence while also supporting measurable competitive performance when implemented as a structured, observable, and instructionally clear coaching approach.
Effects of Rest Interval Length on Muscle Hypertrophy in Amateur Bodybuilders
Rest interval length is a routine programming variable in bodybuilding, yet its chronic influence on hypertrophy in trained recreational competitors remains debated. This study compared 60 s, 90 s, and 180 s inter-set rest intervals during a supervised 10-week hypertrophy-oriented program in amateur bodybuilders. Thirty-six natural amateur bodybuilders (24 men and 12 women) with at least two years of resistance-training experience were randomly assigned to one of three rest-interval conditions. All groups completed the same five-day split routine, identical exercise order, matched repetition targets, and progressive overload; the only programmed difference was rest duration. Primary outcomes were ultrasound-derived muscle thickness of the vastus lateralis and biceps brachii. Secondary outcomes were bench press and back squat one-repetition maximum (1RM), body composition, and cumulative training volume. Assumption checks included the Shapiro-Wilk and Levene tests. Between-group differences in change scores were examined using one-way analysis of variance with Tukey-adjusted post hoc comparisons, and within-group changes were tested with paired-samples t tests. Results: Baseline characteristics did not differ between groups (all p > 0.80). Vastus lateralis thickness increased by 3.9%, 8.0%, and 8.8% in the 60 s, 90 s, and 180 s groups, respectively. Biceps brachii thickness increased by 4.2%, 7.4%, and 8.9%, respectively. Group effects were significant for vastus lateralis change (F = 39.81, p < 0.001, eta squared = 0.71) and biceps brachii change (F = 28.00, p < 0.001, eta squared = 0.63), with both 90 s and 180 s outperforming 60 s. Bench press and squat 1RM improved in all groups, but strength gains were larger with 90 s and 180 s rest. Cumulative training volume was also higher in the longer-rest conditions and was positively associated with the composite hypertrophy response (r = 0.59, p < 0.001). In amateur bodybuilders, moderate-to-long rest intervals appear to support superior hypertrophy and strength development compared with 60 s rest, largely through better preservation of weekly training volume. A 90 s interval seems to provide the most practical balance between session efficiency and adaptation.
Effects of Training Intensity Distribution on Aerobic Capacity, Lactate Threshold, and Fat Oxidation in Well-Trained Cyclists
Purpose: Training intensity distribution is widely regarded as one of the main organizers of endurance training, yet its practical influence on aerobic capacity, lactate-threshold power, and fat oxidation in already well-trained cyclists remains incompletely resolved. Methods: Thirty-six well-trained male cyclists were randomized to polarized, pyramidal, or threshold-oriented training for 10 weeks. Training was monitored using power meters, heart-rate records, and session-rated perceived-exertion data. Before and after the intervention, participants completed a graded cycling test to determine VO₂max and lactate-threshold power, a submaximal protocol to profile fat oxidation and determine peak fat oxidation and power at Fatmax, and a standardized laboratory assessment of peak aerobic power. Normality was checked using the Shapiro–Wilk test. Baseline differences were examined with one-way ANOVA, and group × time effects were tested with repeated-measures ANOVA followed by Bonferroni-adjusted post hoc comparisons. Results: Significant group × time effects were observed for VO₂max (p = 0.031), peak aerobic power (p = 0.028), lactate-threshold power (p = 0.016), power at Fatmax (p = 0.009), peak fat oxidation (p = 0.004), and respiratory exchange ratio during submaximal exercise (p = 0.011). The polarized group showed the largest overall improvements, the pyramidal group showed intermediate responses, and the threshold-oriented group showed the smallest changes across most outcomes. Conclusions: In well-trained male cyclists, the distribution of training intensity influenced not only central aerobic markers but also submaximal substrate-use responses. A program dominated by low-intensity training with a modest but clear high-intensity component appeared to provide the most favorable integrated response for aerobic capacity, lactate-threshold power, and fat oxidation.
Effects of Regular Physical Activity on Cardiorespiratory Fitness and Body Composition in Young Adult Men
Regular physical activity is considered an important determinant of health-related fitness, yet the magnitude of its association with cardiorespiratory fitness and body composition can vary substantially among young adults. This study examined whether habitual physical activity level was associated with estimated maximal oxygen uptake and body-composition indicators in young adult men. A cross-sectional analytical design was used with 132 apparently healthy men aged 18-25 years. Weekly physical activity was assessed using the International Physical Activity Questionnaire-Short Form and expressed as MET-minutes per week. Participants were classified as low active, moderately active, or highly active. Cardiorespiratory fitness was estimated using a graded treadmill test. At the same time, body mass, body mass index, waist circumference, body fat percentage, and fat-free mass were assessed using standardized anthropometry and multi-frequency bioelectrical impedance analysis. Between-group differences were examined using one-way analysis of variance with Bonferroni-adjusted post hoc comparisons. Pearson correlation and multiple linear regression were used to evaluate associations among physical activity, fitness, and body-composition variables. Statistical significance was set at p < 0.05. Weekly physical activity differed significantly across groups (p < 0.001). Estimated VO2max increased from the low-activity group (38.1 ± 5.1 mL·kg-1·min-1) to the moderate-activity group (42.9 ± 5.2 mL·kg-1·min-1) and high-activity group (49.5 ± 7.1 mL·kg-1·min-1), F(2,129) = 29.09, p < 0.001. Body fat percentage was lower in the highly active group (16.5 ± 4.9%) than in the low-activity group (20.9 ± 4.5%), F(2,129) = 11.31, p < 0.001, while body mass index and fat-free mass did not differ significantly. Physical activity was positively correlated with estimated VO2max (r = 0.52, p < 0.001) and inversely correlated with body fat percentage (r = -0.30, p < 0.001) and waist circumference (r = -0.32, p < 0.001). In adjusted regression models, physical activity remained a significant predictor of estimated VO2max and body fat percentage. Higher regular physical activity was associated with better cardiorespiratory fitness and a more favorable adiposity profile in young adult men. The strongest and most consistent association was observed for estimated VO2max, suggesting that aerobic fitness may be particularly sensitive to habitual activity level during early adulthood.
Effects of Caffeine Supplementation on Anaerobic Performance, Reaction Time, and Fatigue in Team-Sport Athletes
Purpose: Team-sport athletes must repeatedly generate short bursts of maximal power, recover quickly between efforts, interpret visual information under time pressure, and preserve decision quality as fatigue accumulates. This study examined whether acute caffeine supplementation improves anaerobic performance, reaction time, and fatigue-related responses in trained male team-sport athletes. Methods: Twenty-four male collegiate team-sport athletes completed a randomized, double-masked, placebo-controlled crossover trial. Participants ingested caffeine (5 mg·kg⁻¹) and an identical placebo 60 min before testing, with trials separated by a 7-day washout. Each visit included simple and choice reaction-time testing, a 30-s Wingate test, and a 6 × 30 m repeated-sprint protocol. Ratings of perceived exertion (RPE) and post-exercise blood lactate were also assessed. Paired-samples t tests were used for single-measure outcomes, while a two-way repeated-measures ANOVA examined sprint-by-sprint performance. Results: Compared with placebo, caffeine increased Wingate peak power (1088 ± 143 vs. 1047 ± 137 W, p < 0.001) and mean power (771 ± 93 vs. 736 ± 84 W, p < 0.001). Simple reaction time (229 ± 20 vs. 241 ± 20 ms, p < 0.001) and choice reaction time (359 ± 32 vs. 381 ± 28 ms, p < 0.001) were faster after caffeine. Repeated-sprint total time was reduced (29.06 ± 0.98 vs. 29.26 ± 0.99 s, p < 0.001), and a condition × sprint interaction showed that the benefit became more evident in the later sprints (p < 0.001). Caffeine also lowered sprint decrement and post-test RPE, while blood lactate was modestly higher. Conclusions: A moderate pre-exercise dose of caffeine improved anaerobic power, accelerated reaction time, and attenuated fatigue-related performance decline in trained male team-sport athletes. These findings support the targeted use of caffeine before activities that combine repeated sprinting with rapid perceptual processing.
Impact of Cooperative Learning Strategies on Physical Performance, Social Interaction, and Enjoyment in Physical Education
Cooperative learning is a pedagogical model that may improve physical, social, and affective outcomes in physical education by requiring students to share responsibility, support peers, and evaluate group progress while remaining actively engaged in movement tasks. This study examined the impact of an eight-week cooperative learning unit on physical performance, social interaction, and enjoyment among male secondary-school students in physical education. A quasi-experimental pre-test/post-test control-group design was used, with 96 male students assigned to intact classes in either a cooperative learning condition (n = 48) or a traditional instruction condition (n = 48). The cooperative learning unit incorporated positive interdependence, individual accountability, promotive interaction, explicit social skills, and group processing across 16 lessons. In contrast, the comparison group received teacher-directed instruction with comparable physical education content, lesson duration, and facilities. Physical performance was measured using a standardized field-test composite; motor skill performance was assessed with a rubric-based score; social interaction was measured using observation and student-report indicators; and enjoyment was assessed with a physical activity enjoyment scale. Statistical significance was set at p < 0.05. The cooperative learning group showed significantly greater improvements than the traditional instruction group in physical performance (mean difference in change = 8.93 points, p < 0.001, Hedges' g = 1.75), motor skill performance (8.31 points, p < 0.001, g = 1.50), social interaction (0.76 points, p < 0.001, g = 2.69), and enjoyment (0.63 points, p < 0.001, g = 1.74). Improvements in social interaction and enjoyment were positively associated with gains in physical and motor performance. The findings indicate that cooperative learning can enhance male students' PE outcomes by linking purposeful peer interaction with sustained physical practice and positive learning experiences.
Copyright (c) 2023 Qubahan Techno Journal https://creativecommons.org/licenses/by-nc-nd/4.0
Comparative Effects of Game-Based Learning and Traditional Instruction on Skill Development and Motivation in School-Aged Athletes
Game-based learning is increasingly used in school sport because it places technical skill practice within tactical, social, and decision-rich playing situations, yet teachers and coaches still need evidence that it can improve both performance and motivation compared with traditional direct instruction. This study compared the effects of an 8-week game-based learning program and a matched traditional-instruction program on skill development, tactical decision-making, motivation, and participation indicators in school-aged athletes. A school-clustered, two-arm field design included 192 athletes aged 12-15 years, with equal representation of girls and boys, allocated to game-based learning (n = 96) or traditional instruction (n = 96). The game-based condition used modified small-sided games, tactical constraints, guided questioning, and reflective breaks, whereas the traditional condition used demonstration, isolated technical drills, corrective feedback, and end-session game play. Primary outcomes were a technical skill composite and a tactical decision-making score, assessed at baseline, week 4, and week 8. Secondary outcomes were intrinsic motivation, enjoyment, perceived competence, autonomy support, attendance, and intention to continue sport participation. Baseline characteristics were comparable between groups. At week 8, game-based learning produced greater improvement in technical skill than traditional instruction (adjusted mean difference = 6.7 points, 95% CI: 3.3-10.1, F = 15.08, p < 0.001, Hedges g = 0.61) and greater improvement in tactical decision making (adjusted mean difference = 7.2 points, 95% CI: 3.6-10.8, F = 15.65, p < 0.001, g = 0.59). Intrinsic motivation, enjoyment, perceived competence, and autonomy support also increased more strongly in the game-based condition, with between-group differences in change ranging from 0.31 to 0.43 scale points (all p < 0.01). Attendance was higher in the game-based group (91.6% vs. 86.5%, p < 0.001), and intention to continue sport participation was more frequent (83.3% vs. 70.8%, p = 0.038). Sex-by-group interaction tests were not significant, indicating broadly comparable effects for girls and boys. These findings indicate that a structured game-based learning approach can improve sport-specific skill, tactical understanding, and motivational quality in school-aged athletes without reducing technical progress, supporting its use in school sport and youth coaching programs where performance development and continued participation are joint priorities.
Associations Between Weekly Training Load, Recovery Status, and Lean Body Mass in Amateur Bodybuilders
Weekly training load is a central programming variable in bodybuilding, but its association with lean body mass is difficult to interpret without accounting for recovery status and the broader nutritional and sleep context. This cross-sectional field study examined associations between weekly resistance-training load, recovery status, and lean body mass in amateur bodybuilders. A mixed-sex sample of 240 amateur bodybuilders (120 women and 120 men; age 25.8 +/- 4.2 years) completed a seven-day training and recovery log, nutrition screening, readiness and soreness ratings, and standardized body-composition assessment. Weekly training load was calculated from session duration multiplied by session rating of perceived exertion and summarized alongside weekly hard sets. Lean body mass and lean body mass index (LBMI) were used as primary outcomes. Statistical significance was set at p < 0.05. Training load showed a positive but curvilinear association with LBMI, with the strongest profile observed in athletes completing high but not excessive weekly loads. Recovery status was independently associated with LBMI after adjustment for age, sex, training experience, protein intake, sleep duration, and training load (beta = 0.26 kg/m2 per recovery point, 95% CI: 0.15 to 0.37, p < 0.001). The training load-by-recovery interaction was significant (p < 0.001), indicating that higher load was most strongly associated with lean mass when recovery ratings were moderate to high. Athletes in stronger recovery profiles had greater odds of achieving a sex-specific high lean-mass profile. Associations were similar in women and men. These findings support a balanced interpretation of bodybuilding adaptation: greater weekly loading is associated with higher lean body mass, but recovery status helps determine whether that load is likely to support adaptation rather than accumulated strain.
Associations Among Muscular Strength, Aerobic Fitness, and Fatigue Resistance in Community-Dwelling Older Adults
Community-dwelling older adults often experience concurrent declines in muscular strength, aerobic fitness, and tolerance to repeated physical effort, and these changes may undermine independence even before overt disability is apparent. This study examined the associations among muscular strength, aerobic fitness, and fatigue resistance in older men living independently in the community. In a cross-sectional analytical design, 156 men aged 60–84 years completed assessments of handgrip strength, 30-s chair-stand performance, 6-minute walk distance, estimated peak oxygen uptake, and a repeated sit-to-stand fatigue-resistance protocol, together with anthropometric and health screening procedures. Normality was evaluated using the Shapiro–Wilk test, group differences across fatigue-resistance tertiles were examined with one-way analysis of variance, and Pearson correlation and hierarchical multiple regression analyses were used to determine whether strength and aerobic fitness were independently associated with fatigue resistance. Participants with high fatigue resistance were younger and demonstrated greater handgrip strength (39.8 ± 4.2 kg), better chair-stand performance (14.3 ± 1.8 repetitions), longer 6-minute walk distance (549 ± 35 m), and higher estimated VO₂peak (26.1 ± 2.5 mL·kg⁻¹·min⁻¹) than those with low fatigue resistance (32.7 ± 4.5 kg, 11.4 ± 1.6 repetitions, 446 ± 37 m, and 21.6 ± 2.2 mL·kg⁻¹·min⁻¹, respectively; all p < 0.001). Fatigue resistance was inversely associated with handgrip strength (r = -0.62, p < 0.001), chair-stand performance (r = -0.60, p < 0.001), 6-minute walk distance (r = -0.69, p < 0.001), and estimated VO₂peak (r = -0.69, p < 0.001). In hierarchical regression, both handgrip strength (β = -0.25, p = 0.003) and 6-minute walk distance (β = -0.38, p < 0.001) remained independently associated with fatigue resistance after adjustment for age, body mass index, and comorbidity burden (model R² = 0.58). These findings suggest that muscular strength and aerobic fitness contribute in complementary ways to fatigue resistance in community-dwelling older men and support exercise strategies that integrate resistance and aerobic training to preserve daily function and physical resilience.
Acute Physiological and Perceptual Responses to Interval versus Continuous Threshold Training in Middle-Distance Athletes
This study compared the acute physiological and perceptual responses to two threshold-based running formats in trained male middle-distance athletes. Twenty male 800-1500 m specialists completed a randomized crossover field protocol consisting of continuous threshold training (CTT; 32 min continuous running at individual second lactate-threshold velocity) and interval threshold training (ITT; 4 × 8 min at the same velocity with 2-min jog recoveries). Heart rate (HR), blood lactate concentration ([BLa]), Borg rating of perceived exertion (RPE), session-RPE (sRPE), affective valence, and 30-min total quality recovery (TQR) were recorded. Paired-samples tests compared session outcomes, repeated-measures ANOVA examined time-course responses, and statistical significance was set at p < 0.05. ITT elicited higher mean HR (177.8 ± 6.3 vs. 170.3 ± 5.3 beats·min−1), greater time above 90% HRmax (19.5 ± 6.4 vs. 13.7 ± 3.5 min), higher post-session [BLa] (5.12 ± 1.31 vs. 4.12 ± 1.10 mmol·L−1), higher end-session Borg RPE (16.2 ± 1.3 vs. 15.3 ± 1.3), and greater sRPE (6.6 ± 1.0 vs. 5.8 ± 1.0) than CTT (all p < 0.05). The [BLa] and HR time courses showed significant condition × time interactions, indicating progressive divergence between formats during the main work period. When the work duration and intensity thresholds were matched, the interval format produced greater cardiometabolic and perceptual load than continuous-threshold running. Coaches should therefore avoid assuming that interval and continuous threshold sessions are interchangeable merely because they share the same nominal threshold speed and work duration.
Twelve-Week Exercise Intervention for Improving Insulin Sensitivity and Body Fat Percentage in Men with Overweight and Obesity
This study examined whether a supervised twelve-week combined exercise program could improve insulin sensitivity and reduce body fat percentage in sedentary men with overweight and obesity. Fifty-six men aged 33–58 years with body mass index between 27.4 and 38.6 kg·m−2 completed a randomized controlled trial and were allocated to either a supervised exercise group (n = 28) or a usual-care control group (n = 28). The intervention combined moderate-intensity aerobic exercise and progressive resistance training performed four times per week. Primary outcomes were homeostatic model assessment of insulin resistance (HOMA-IR) and body fat percentage. Secondary outcomes included fasting glucose, fasting insulin, waist circumference, body mass, fat-free mass, and estimated VO2peak. Baseline comparability was assessed with independent-samples t tests. Intervention effects were evaluated with baseline-adjusted analysis of covariance supported by paired-samples t tests for within-group change and Pearson correlation for the attendance-response analysis. Results: Baseline values did not differ between groups (all p > 0.80). After twelve weeks, HOMA-IR decreased from 4.49 ± 0.83 to 3.09 ± 0.83 in the exercise group and from 4.54 ± 1.00 to 4.42 ± 1.05 in the control group. Body fat percentage decreased from 32.77% ± 3.91% to 29.83% ± 4.15% in the exercise group, whereas only a trivial change was observed in the control group. Significant adjusted between-group effects were found for HOMA-IR, body fat percentage, waist circumference, body mass, fasting glucose, fasting insulin, estimated VO2peak, and fat-free mass (all p < 0.001 except fat-free mass). Session attendance was positively associated with the magnitude of HOMA-IR improvement (r = 0.53, p = 0.004). A twelve-week combined exercise intervention produced clinically meaningful improvements in insulin sensitivity, adiposity, and fitness in men with overweight and obesity. The findings support structured exercise as a practical non-pharmacological strategy for early metabolic-risk reduction.