International journal of exercise science最新文献

Figure skaters typically have higher bone mineral density (BMD) than the general population. However, the current literature is limited to cross-sectional studies. The objective of this study was to determine two-year changes in volumetric BMD, bone microarchitecture, and estimated bone strength in elite national and development level Canadian figure skaters. Eleven female figure skaters aged 14+ years were recruited for this longitudinal study. Measurements occurred annually. High-resolution peripheral quantitative computed tomography (HR-pQCT) scans of the radius and tibia underwent three-dimensional image registration. Total (Tt), cortical (Ct) and trabecular (Tb) volumetric BMD (mg HA/cm³), trabecular thickness (TbTh, mm) and cortical thickness (CtTh, mm) were determined. Finite element analysis estimated bone strength. Linear mixed effects models with subject random intercept and time×level interaction evaluated the influence of TtBMD over two-years. Eleven figure skaters completed baseline and one-year data collection, and nine completed the two-year study. All skaters were included in our models and were either national (n=5, 18.6-28.1 years) or development (n=6; 14.4-17.7 years) athletes. Significant time-by-level status (development or national) interactions indicated increases over time in development level athletes only for TtBMD, CtBMD, CtTh and bone strength at the radius and TtBMD, TbBMD, TbTh and bone strength at the tibia (p<0.01 for all). Bone outcomes did not change significantly over the two years in national level figure skaters. Changes in bone density, microarchitecture and strength were only observed in the younger, development level athletes. Given the differences in age between development and national level figure skaters, these results are understandable.

This study aimed to assess the acute physiological responses to a single bout of rope climbing high-intensity interval training (RC-HIIT) and compare the responses between sexes as no data currently exists on this training modality. Following an overnight fast, body composition was assessed, and resting measurements were recorded. Participants then completed an exercise protocol consisting of 10 rounds of maximal effort rope climbing using a 30:60 second work:rest ratio. Gas analysis and heart rate (HR) were recorded continuously. Blood lactate (BLa) was measured following the final work interval. Participants remained seated for 25 minutes post-exercise to assess V̇O₂ recovery. 22 recreationally active participants (11M/11F, 24 ± 7 yrs, 171.5 ± 7.9 cm, 69.9 ± 12.1 kg, 18.9 ± 6.0% body fat) completed the study. Combined average HR during exercise was 141 ± 19 bpm (74.0 ± 10.4% age predicted maximal HR (APMHR)) and peak HR reached 172 ± 17 bpm (90.3 ± 8.8% APMHR). Average exercise V̇O₂ was 18.8 ml/kg/min with peak V̇O₂ values of 27.2 ml/kg/min. Energy expenditure during exercise was 99 ± 28 kcal. Post-exercise BLa was 9.8 ± 3.1 mmol. PACES scores indicated high enjoyment with this modality (101.5 ± 15.9). Average exercise V̇O₂, peak V̇O2, energy expenditure, and post-exercise BLa were greater in males than females (p < 0.05). No sex differences were observed for HR responses or exercise enjoyment. A 15-minute RC-HIIT bout induces HR responses indicative of moderate- to vigorous-intensity exercise in both sexes with greater physiological responses in males compared to females.

Caffeine, alone or in conjunction with an acute bout of resistance exercise (RE), increases measures of pulse wave reflection (PWR), with most studies focusing on men. Therefore, the purpose of this study was to investigate caffeine's effects on measures of PWR alone and following an acute bout of RE in young, healthy, resistance-trained women. Eleven resistance-trained women completed an acute bout of RE using free-weights with repetitions to failure for squat and bench press with caffeine (4mg/kg) and a placebo. Measures of PWR were measured at Rest, 50 minutes following ingestion (caffeine or placebo), immediately following the acute bout of RE and after 10 minutes of recovery. There were no differences (p > 0.05) between caffeine and placebo conditions for measures of PWR at any time point. Aortic pulse pressure (APP), augmentation pressure (AP), augmentation index (AIx), augmentation index normalized at 75bpm (AIx@75), systolic pressure time index (SPTI), and left ventricular wasted energy (ΔEw) significantly increased (p < 0.01) following the acute bout of RE for up to 10 minutes in both conditions while diastolic pressure time index (DPTI) significantly decreased (p < 0.01). There was no change in aortic systolic blood pressure (ASBP), aortic diastolic blood pressure (ADBP), time of the reflected wave (Tr) and subendocardial viability ratio (SEVR) following the acute bout of RE in either condition (p > 0.05). Collectively, this study suggests that a caffeine dose of 4mg/kg does not alter measures of PWR beyond the individual influence of an acute bout of RE in resistance-trained women.

ACL injuries often occur when athletes perform cognitive tasks while performing a landing/cutting movement. This study investigated the effects of secondary cognitive tasks on hip and knee biomechanics during single limb landing. Sixteen recreational athletes (10 females and 6 males, age: 21.6 ± 2.5 years, mass: 65.2 ± 8.9 kg, height 1.66 ± 0.07 m) performed landings on their dominant limb as a single task and while simultaneously performing secondary cognitive tasks (mental arithmetic) provided through audio and visual means. Hip and knee joint angles and moments were calculated in all three planes of motion and analysed using statistical parametric mapping repeated-measures ANOVA. Hip adduction angle was significantly greater in audio and visual secondary task conditions compared to the single task condition during 88% to 100% of the landing period. Hip internal rotation was significantly greater in the visual secondary task condition compared to the single task condition during 68% to 92% of the landing period. There were no significant differences between task conditions for hip moments, knee moments or knee angles in all three planes of motion. These findings suggest secondary cognitive tasks, whether visual or audio, affect hip kinematics which may reflect reduced dynamic stability at the hip, contributing important further knowledge on the effect of secondary cognitive tasks during landing biomechanics.

Accurate determination of metabolic thresholds is essential for designing effective endurance training. This study aimed to apply a multi-visit Step-Ramp-Step (SRS) protocol to identify aerobic (VT1) and anaerobic (VT2/RCP) thresholds in trained endurance runners, with a particular focus on delineating the isocapnic buffering region-the ventilatory phase between VT1 and VT2 where carbon dioxide (PetCO₂) remains stable despite rising ventilation. Twelve trained male runners (mean age: 27.1 ± 1.9 years; VO₂max: 60.5 ± 2.1 ml·kg^-1·min^-1) completed the SRS protocol across separate lab visits. Each session included a 4-minute moderate-intensity phase, a progressive ramp to volitional exhaustion, and a 4-minute heavy-intensity step following a 30-minute recovery. Breath-by-breath gas exchange data (VO₂, VCO₂, VE, RER, PetO₂, PetCO₂) were analyzed using 20-second smoothing. Results showed that VT1 and RCP occurred at 73.2 ± 4.1% and 89.6 ± 3.8% of VO₂max, respectively. The isocapnic buffering zone spanned ~16.4% of the VO₂max range. Unlike previous SRS studies focused on cycling, this study uniquely applies the protocol to running and specifically quantifies the buffering region. These findings support the use of SRS running protocols for efficient, individualized assessment of metabolic transitions in endurance athletes.

Visceral adipose tissue (VAT) is a significant contributor to insulin resistance in type 2 diabetes (T2D). The effectiveness of time-efficient high-intensity interval training (HIIT) in reducing VAT has not been reviewed. A systematic search conducted on PubMed, Embase, and SPORTDiscus up to April 2025 for randomized controlled trials that compared HIIT with non-exercise control and quantified VAT using imaging identified five trials (n = 138) that met inclusion criteria. Risk of bias was assessed using a nine-item modified PEDro scale. Four trials reported significant reductions in VAT after 8-12 weeks of thrice-weekly cycling HIIT sessions. Furthermore, all five HIIT interventions showed significant reductions in glycosylated hemoglobin compared to the control groups. Overall, supervised HIIT appears effective, resulting in clinically significant reductions in VAT and glycemic control. Nonetheless, these conclusions are limited by small sample sizes, protocol heterogeneity, and short follow-up durations. Larger trials that standardize interval structures, evaluate unsupervised adherence, and investigate mechanistic mediators are necessary to confirm the sustainability of outcomes and inform clinical applications of HIIT for patients with T2D.

Personalized fitness training is designed to improve physical health and fitness, but may also promote mental health and well-being. The purpose of this study was to determine whether there are positive psychological outcomes for clients participating in a community-based personalized fitness program led by undergraduate Exercise Science students. A total of 44 participants completed a battery of psychological scales both before and after participation in a 12-week university-sponsored personalized fitness training program. Psychological measures included the Exercise Attitudes Scale, Self-Efficacy Scale for Exercise, Short Warwick-Edinburgh Mental Well-Being Scale, Health Status Questionnaire, and Visual Analog Scale for quality of life. In addition to expected gains in various biometric indicators of physical fitness, we observed significant improvements in clients' attitudes toward exercise, mental well-being, perceived health, and quality of life. Effect sizes were generally in the small to medium range (0.19 to 0.58) across 15 psychological measures. Results provide convincing evidence of the mental health benefits associated with participation in personalized fitness training. Our university-sponsored fitness training program can serve as a model program for both engaging undergraduate students in authentic fitness training experiences and promoting community health and wellness.

Parkinson's disease (PD) is second in occurrence among neurodegenerative disorders after Alzheimer's disease and significantly impacts gait and mobility. This research tested the effect of the NewGait rehabilitative device in PD impaired individuals. Twenty individuals with PD participated in this study. Walking gait for three conditions were analyzed: Normal, wearing NewGait and Post-NewGait. Standard spatial and temporal analysis measures as well as nonlinear measures from recurrence quantification were compared to determine any effects of the device on walking gait. NewGait was perceived to be both comfortable to wear as well as resulted in increased ease of movement. Step width was increased while wearing NewGait while step length was unchanged. No differences were found in temporal measures: cadence, stride time and double support time. Wearing NewGait resulted in a slight, but not significant decrease in walking velocity compared to Normal. Post-NewGait gait velocity was increased compared to wearing NewGait. Based only on these standard linear spatiotemporal measures, NewGait is somewhat intrusive for gait Parkinsonian individuals, resulting in a less effective gait. The recurrence-based analysis however, found that compared to Normal, Determinism and Laminarity was increased while wearing NewGait and Post-NewGait. Entropy was also increased while wearing NewGait and there was a tendency towards increased Entropy while walking after wearing NewGait. These results suggest NewGait allows for greater predictability and complexity of the gait pattern with increased dynamic stability than walking without NewGait. Therefore, there is potential for longer-term beneficial effects of NewGait in rehabilitation of Parkinsonian gait.

Sedentary behaviors contribute to law enforcement officer fitness declines over a career. An officer's motivation (desire to exercise) and self-efficacy (belief in ability to exercise) could affect whether they exercise and predict resulting fitness. Data from 60 officers (48 men, 12 women) were analyzed. Motivation (amotivation, external, introjected, identified, integrated, and intrinsic regulation) was measured via the Behavioral Regulation in Exercise Questionnaire. A 6-item questionnaire assessed coping (confidence in exercising under challenging conditions) and scheduling (confidence in scheduling exercise) self-efficacy. General fitness variables included sit-and-reach, grip strength, 60-s push-ups, 60-s sit-ups, and step test recovery heart rate. Job-specific fitness variables included 99-yard obstacle course, body drag, 6-foot chain link fence and solid wall climbs, and 500-yard run. Stepwise regression, controlling for sex, derived relationships between motivation and self-efficacy, with general and job-specific fitness (p<0.05). Grip strength was predicted by introjected, identified, and integrated motivation (~71% explained variance). Push-ups were predicted by integrated motivation and coping self-efficacy (~43% explained variance). The obstacle course, fence and solid wall climbs, were predicted by coping self-efficacy (~24-47% explained variance). Internal motivation and coping self-efficacy predicted certain general and job-specific fitness metrics. Grip strength, an indicator of muscular strength, was predicted by introjected (internal rewards), identified (exercise is valued), and integrated (exercise integrated within beliefs) regulation. Integrated regulation and coping self-efficacy, or confidence to overcome barriers to exercise, predicted push-ups as a muscular endurance metric. Coping self-efficacy could also contribute to the exercise needed to maintain job-specific fitness relative to obstacle courses and obstacle clearance.

For advancement of public health through exercise, exercise intensity and enjoyment are important. We aimed at testing whether self-selected exercise intensity was higher during treadmill exercise than during indoor cycling. Secondly, the enjoyment associated with the two activities was evaluated. Thirdly, in a person-centered analysis, taking into account the participants' preference for mode of activity, we assessed whether preference for one of the activity modes was accompanied by greater intensity. Healthy adults (n=21) participated in the repeated measures crossover-designed study. They performed 16-min bouts of treadmill exercise and indoor cycling at self-selected intensity. Heart rate was recorded to determine the intensity. Enjoyment associated with the exercise activity was determined by a questionnaire. Intensity in terms of heart rate as percent of maximal heart rate was not different between treadmill exercise and indoor cycling (p=0.148). Enjoyment, on the other hand, was 4.4±7.6 units greater for treadmill exercise than for indoor cycling (p=0.012). Seventeen of the participants had a preferred mode of activity, when asked before any testing. The person-centered analysis, which took into account the participants' preference for the mode of activity, showed that intensity was 4±7 percentage points higher (p=0.029) during the preferred mode of activity as compared to the other activity. In summary, the study showed that the self-selected intensity was not different between treadmill exercise and indoor cycling, while the enjoyment was found to be greater during treadmill exercise. A person-centered analysis showed that intensity was higher during the preferred mode of activity than during the other activity.