International journal of exercise science最新文献

This study aimed to examine weekly variations and within-subject relationships between internal training intensity (ITI), perceived recovery (TQR), neuromuscular performance (CMJ), and perceived muscle soreness (PMS) during a four-week preseason period in professional soccer players. Twenty-three soccer players (age 24.8 ± 4.4 years; height 182 ± 7 cm; body mass 74.6 ± 6.7 kg) classified as Tier 3 athletes from the Croatian Second Soccer League were monitored using session rating of perceived exertion, TQR scales, countermovement jump tests, and PMS questionnaires. A significant reduction in ITI and concurrent improvement in TQR scores were observed across the preseason, with the highest intensity in week 1 and the lowest recovery in week 2. CMJ height performance declined during peak fatigue but rebounded as training intensity tapered. Repeated-measures correlations revealed negative associations between weekly ITI and TQR of the following week (r_rm = -0.72), and between ITI and CMJ (r_rm = -0.55), indicating that greater training intensities may impair both perceptual and neuromuscular recovery. The training stimulus-recovery difference index was positively associated with next-day TQR, suggesting it may serve as a sensitive marker of session-level readiness. These findings highlight the interplay between intensity, recovery, and fatigue, emphasizing the utility of low-cost subjective and objective tools for monitoring preseason responses and guiding individualized training strategies in elite soccer settings.

Implicit biases are unconscious, internally held beliefs shaped by cultural norms, societal structures, and personal experiences and are often related to societal constructs such as race, gender, age, body shape, and ability. The aim of this study was to explore the relationship between social identity, industry role, and implicit biases in fitness professionals. Participants (n=296) were randomly assigned two implicit association tests (IATs): disability, weight, gender, skin-tone, or age. IATs measured implicit bias through word and pictorial associations and timed response to word/picture stimuli. Interviews (n=25) were conducted to further examine participants' psychosocial beliefs and experiences related to biases. Quantitative data revealed moderate preferences for younger, lighter skinned, thin, male individuals concurrent with a strong preference for able bodies. Certified personal trainers and strength and conditioning coaches held significantly stronger preferences towards younger people compared to participants with other certifications. Older participants were significantly more likely to prefer White, able-bodied, thin individuals compared to their younger counterparts. Black, Indigenous, and People of Color (BIPOC) participants and participants certified as personal trainers reported a significantly greater gender bias compared to White participants and those with other certifications. Interviews revealed themes including unacknowledged biases, body aesthetics conflict, negative/positive weight associations, and negative/positive reactions to bias-related discourse. In this study's sample of fitness professionals, both quantitative and qualitative data revealed preferences for the dominant body type (e.g., young, White, thin, able-bodied, and male). Addressing these biases is an imperative step in upholding the quality of care that clients receive.

Transgender people may opt for the use of sex steroids and, in some cases, hormone blockers, which can lead to changes in body fat distribution. The aim of this study was to verify the accuracy of anthropometric equations to estimate the body density (BD) of transgender men who are undergoing Gender-Affirming Hormone Therapy (GAHT). Four transgender men (25-32 years old), who had performed GAHT for at least six months and used the hormone testosterone cypionate participated in the study. The reference criteria for BD was air displacement plethysmography (ADP). In addition, BD was estimated using anthropometric equations for both male and female sexes (Durnin & Womersley, 1974; Jackson & Pollock 1980; Lohman, 1981). The body fat percentage (%BF) was estimated by the Siri equation. For two participants (Cases 1 and 3), the equations for males underestimated the %BF, while only for Case 3 the equation for both sexes underestimated the %BF. For the other two participants (Cases 2 and 4), all equations overestimated the %BF. Of note, one participant undergoing GAHT for six months showed a %BF assessed by ADP like values obtained using equations for cisgender women, while those with longer time on GAHT presented similar %BF obtained by ADP to obtained by equations developed for cisgender men. In conclusion, the results of this study indicate the need to develop specific anthropometric equations for the transgender population. In addition, the time on GAHT of the transgender person seems to be a critical factor.

This study aimed to evaluate the reliability and predictive validity of specific athletic running drills: A-skip, B-skip, bounding step, and jumps, in relation to sprint performance over 5 m and 20 m distances. Sixty-three young males (mean age: 21.3 ± 2.1 years; body height: 183 ± 6.5 cm; body weight: 77 ± 9.3 kg) were enrolled in the study. Running drill performance was recorded on an athletics track using high-speed cameras and evaluated based on predefined criteria and a scoring system. Reliability was assessed using intraclass correlation coefficients (ICC) and coefficients of variation (CV). Predictive validity was determined via Pearson correlations and multiple linear regression analyses. The results indicated good to excellent inter-rater reliability for A-skip (ICC = 0.897) and jumps (ICC = 0.9), while B-skip and bounding step showed good reliability (ICC = 0.808 and 0.874, respectively). The 20 m sprint demonstrated excellent reliability (ICC = 0.969, CV = 2.07%), while the 5 m sprint had good reliability (ICC = 0.863, CV = 3.58%). B-skip emerged as the strongest predictor for both sprint distances, with significant negative associations (5 m: β = -0.531, p < 0.01; 20 m: β = -0.322, p < 0.05). These findings suggest that specific drills, particularly B-skip, demonstrate high inter-rater reliability and moderate predictive validity as indicators of short-sprint performance, with B-skip showing the strongest association. Coaches and practitioners can use these drills to enhance training programs to improve acceleration and speed over short distances.

Performing training sessions in hypoxia leads to a decrease in effort quality. The inter-effort recovery intermittent hypoxia model seems to ensure training session performance. The aim of this study is to investigate the effects of sprint interval exercise under normoxic (NOR), continuous hypoxic (HYP), and inter-effort hypoxic (IEH) conditions on force parameters. Seven swimmers (age: 26.04 ± 4.64 years) volunteered and performed one session of the 10 × 30-s all-out tethered swimming efforts with 4-min passive recovery intervals for each condition. Considering the simulated altitude at F_iO₂ = 0.13 and NOR at F_iO₂ = 0.209. The sessions were separated at least 48 hours. The peak force (PF), mean force (MF), impulse, fatigue index (FI) and percentage mean force relative to peak force (PF_PERC) were determined for each effort. The force parameters were higher on IEH (PF: Δ = 21.32 N; MF: Δ = 9.65 N; impulse: Δ = 626.78 N·s) and HYP (PF: Δ = 15.80 N; MF: Δ = 6.92 N; impulse: Δ = 621.77 N·s) in relation of the NOR (p < 0.001). PF_PERC evidenced lower values in IEH in relation to HYP (Δ= 3.1 %, p = 0.017). The HYP and IEH condition can be considered a model that enhances performance in force parameters compared to the NOR condition.

Small-sided games (SSG) are often used as a multifunctional form of specific training that allows development of various key components during soccer training. The main goal of this research was to determine the differences in internal and external load of different small-sided games (SSG) during preseason. The secondary goal was to analyze specific technical demands during these SSG. Twelve players of the First Croatian Junior League (U19) participated in this research in the fourth week of the preparatory period for the competitive season 2019/2020. Testing was conducted on two separate days with a day of rest in-between. Internal (IL) and external load (EL) variables and some technical demands were observed in the research. Significant differences in IL and EL were found between different types of SSG. Overall, IL (primarily HRmax (F=4.24, p<0.05, η²=0.44) and 90-100%Hrmax (F=5.18, p<0.01, η²=0.37) and EL (primarily TD (F=3.50, p<0.05, η²=0.28) and WR (F=6.26, p<0.01, η²=0.41) increased during 5vs.5 with GK (goalkeeper) series. On the other hand, greater EL (WR (F=11.43, p<0.001, η²=0.51), 2.1-3.0 m/s (F=7.03, p<0.001, η²=0.39) was observed in regular 6vs.6 while some IL parameters (%HRmax (F=6.07, p<0.01, η²=0.36) and HRmax (F=8.60, p<0.001, η²=0.44) were higher in two 6vs.6 GK series. In terms of technical demands, incidences of the PASS, RECEIVE and TURN variables were on average higher in 5vs.5 and 6vs.6 compared to 5vs.5GK and 6vs.6GK. To conclude, different SSG generated different IL and EL outcomes, especially with the addition of goalkeeper. Also, SSG could be used as a useful training tool for pre-season training in order to improve functional abilities while adding specific match-like situations for players.

This study was to examine the effect of a mental training program, including a combination of autogenic training and imagery, on a number of mental skills and on the development of personality traits - psychological hardiness as well as conscientiousness, openness to experience, and neuroticism - in Adolescent male volleyball players. 60 adolescent male volleyball players (aged 15-17) participated in a two-group, pretest-posttest design. The experimental group (n = 30) completed 8-week mental skills training program, including imagery, self-talk, attention control, and relaxation, while the control group (n = 30) followed regular training. Psychological hardiness and selected personality traits were measured pre- and post-intervention using validated scales, and data were analyzed with mixed-design ANOVA and effect sizes. result show significant improvements in psychological hardiness (commitment, control) and personality traits (conscientiousness, openness to experience) in the experimental group (p < 0.01), with modest decreases in neuroticism. Large effect sizes (Cohen's d = 0.57-1.19; partial η² = 0.07-0.37) highlight the practical impact of the intervention compared to the control group, which showed minimal changes. Structured mental skills training significantly enhanced psychological hardiness, conscientiousness, and openness, modestly reduced neuroticism, and demonstrated practical impact, supporting its integration into adolescent male volleyball players' holistic development programs.

Track and field (T&F) throwers are a prominent subgroup of athletes that may be at risk for the development of Metabolic Syndrome (MetSyn) and other cardiometabolic disease conditions. However, limited research exists examining the prevalence of MetSyn in these athletes. Therefore, the purpose of this study was to examine the incidence of MetSyn and associated risk factors in collegiate throwers. Collegiate Division I men (n=17) and women (n=4) T&F throwers participated in a single day of lab assessments, which included anthropometrics, body composition, blood pressure, a venous blood draw, and aerobic capacity. MetSyn was diagnosed based on the following clinical markers: HDL, triglycerides, glucose, waist circumference, and blood pressure. MetSyn was present in 47% of men and 0% of women athletes. The most common risk factors were excessive waist circumference (men: 65%, women: 25%), reduced HDL (men: 59%, women: 50%), and elevated systolic blood pressure (men: 47%, women: 25%). BF% was associated with SBP (r=0.71), DBP (r=0.74), insulin (r=0.58), insulin resistance (r=0.58), triglycerides (r=0.51), and VO_2max (r=0.79) (p<0.05). This study observed a high incidence of MetSyn and other associated adverse cardiometabolic biomarkers in collegiate T&F throwers. Regular assessments of body composition and aerobic capacity may serve as practical and effective tools to identify at-risk athletes and guide targeted interventions aimed at reducing long-term cardiometabolic disease risk.

This study explored how age affects postural stability (PS) in firefighters by focusing on two key objectives: 1) determining if age affects right-to-left anterior (ANT) reach distance asymmetry (ASYM) during the Motor Control Screen (MCS) test and 2) assessing whether the proportion of firefighters not meeting the greater than two-foot length (2FL) criterion for ANT reach differs across age groups. Data from 95 male firefighters were analyzed using the MCS ANT reach test, part of the Y-Balance Test (YBT). The key outcomes were the difference in ANT reach distances between legs (ASYM) and the proportion reaching less than or equal to 2FL. Statistical analyses used Mann-Whitney U tests for ASYM and chi-square tests for proportions. No statistical difference in ASYM was found between younger and middle-aged firefighters (U=1025, p=0.501, r=-.069). Similarly, the proportion of firefighters not meeting the greater than 2FL criterion did not significantly differ across age groups for both right and left ANT reaches (p= 0.997, ϕ=.000 for right and p= 0.547, ϕ=-.062 for left). These findings indicate that age does not significantly influence right-to-left ANT reach ASYM or the likelihood of failing to meet the greater than 2FL criterion in this firefighter population. The results suggest that PS, as measured by ANT reach ASYM and the greater than 2FL criterion, does not significantly decline with age among firefighters. This may be due to the physical demands of firefighting. Future research should explore how ANT reach measures relate to injury risk and evaluate age-specific balance training interventions.

Previous research on limb asymmetries of athletes participating in dominant-sided sports lacks an athletic control group. This study aimed to determine the magnitude of upper limb asymmetries in dominant-sided athletes (tennis players) compared to nondominant-sided athletes (cross-country runners). Men and women university athletes (10 tennis, 11 cross-country) participated. Dual-energy x-ray absorptiometry (DXA) was used to measure bone mineral content (BMC), bone mineral density (BMD), and lean mass (LM) of the whole body, upper extremities, and forearms. Circumference measurements were taken at mid-biceps and widest part of the forearms. Bony breadth of the elbow was measured with sliding calipers placed at the medial and lateral epicondyles. Grip strength was assessed with a dynamometer. Mixed-model ANOVA was used to analyze data between dominant/nondominant sides and between sports. There were no significant differences in age (p = .150), height (p =.783) or body mass (p = .066) between teams. No differences were shown between sports for total body BMC (p = .544), total body BMD (p = .535), or total body LM (p = .843). Sport × side interaction was significant (p < .05) for lower arm circumference, elbow bony breadths, total upper extremity LM, total upper extremity BMC, total upper extremity BMD, forearm BMC, ultra-distal forearm BMC, mid-distal forearm BMC, one-third forearm BMC, and ultra-distal forearm BMD. Morphological differences between sports were localized to the arm. Sport specificity influences mass and volume (circumference, LM, BMC) of the limb, with BMD particularly enhanced in ultra-distal forearm.