Journal of Sports Medicine and Physical Fitness最新文献

Background: The oxygen uptake efficiency slope (OUES) is a submaximal, effort-independent index derived from cardiopulmonary exercise testing that reflects aerobic fitness. Although OUES has shown strong correlations with maximal oxygen uptake (VO2max) in clinical populations, its validity and relationship with habitual physical activity in healthy middle-aged adults remain underexplored. This study aimed to evaluate OUES as a marker of aerobic fitness and examine its association with self-reported physical activity in this demographic.

Methods: Twenty-one middle-aged adults (14 women, seven men; mean age 63.3±3.8 years) without known cardiopulmonary disease were recruited. Participants completed the Sports Medicine Australia pre-exercise screening questionnaire, including weekly physical activity reporting. Each participant underwent a graded treadmill test (Bruce protocol) to submaximal effort, with oxygen uptake (VO2) and ventilation (VE) measured continuously using a validated portable metabolic system. OUES was calculated from the linear regression of VO2 against the log10VE). VO2max was estimated via a resting seismocardiography device (VentriJect Seismofit^®). Pearson's correlations and one-way ANOVA were used to evaluate relationships between variables and tertile-based fitness groups. An independent-samples t-test compared OUES values by sex.

Results: Mean peak VO2 was 25.2±4.1 mL/kg/min; mean OUES was 1629.6±522.0 mL/min per log L/min. OUES showed a moderate but non-significant correlation with estimated VO2max (r=0.415, P=0.069) and no meaningful association with self-reported physical activity (r=-0.012, P=0.960). One-way ANOVA showed significant differences in VO2max across VentriJect VO2 tertiles (P<0.001, η²=0.65), but not in OUES (P=0.162). Males had significantly higher OUES values than females (2171±391 vs. 1366±282; P<0.001), with a large effect size (Cohen's d=2.50).

Conclusions: OUES can be reliably obtained using a brief treadmill protocol and portable metabolic equipment in middle-aged adults. While not associated with self-reported activity, OUES showed moderate correlations with VO2max and differentiated higher-fitness individuals, especially by sex. These findings support OUES as a valid submaximal marker of cardiorespiratory fitness and underscore the importance of objective fitness measures alongside self-report tools in health and exercise settings.

Introduction: While it is understood that resistance exercise in humans induces muscle growth primarily via muscle hypertrophy, there is some debate as to whether muscle hyperplasia also occurs. The purpose of this meta-analysis was to quantitively assess whether the presence of muscle hyperplasia occurs in humans performing resistance training.

Evidence acquisition: Medline, Scopus, and Web of Science were searched on May 17, 2024. Studies that measured or reported sufficient data to estimate muscle fiber number before and after resistance training were included in a three-level random effects model. Fiber number was estimated from the ratio of muscle cross-sectional area to fiber cross-sectional area.

Evidence synthesis: A total of 11 studies met the inclusion criteria. Changes in fiber number were estimated in the biceps brachii or vastus lateralis muscles. Meta-analysis results indicated that resistance exercise did not significantly alter the estimated number of muscle fibers (ES: 4086; 95% CI: -6430, 14,604; P=0.419). Additionally, the presence of muscle hyperplasia was not moderated by prior training status, training duration, or the muscle group analyzed (all P>0.05).

Conclusions: These findings suggest that meaningful changes in muscle fiber number are unlikely to occur in humans following resistance training interventions lasting up to 6 months. While muscle hyperplasia was not evident, it may be difficult to detect due to the relatively short duration of the included training interventions and/or difficulties in estimating muscle fiber number, which resulted in a wide range of estimates across studies.

Background: The Body Oxygen Level Test (BOLT), also known as the control pause in the Buteyko method, is a breath-hold test proposed to reflect CO2 tolerance and breathing efficiency. Although popularized as a fitness indicator, its relationship to aerobic capacity and physical activity in healthy adults remains unclear. This study examined associations between BOLT score, maximal oxygen uptake (VO2max), treadmill time to exhaustion (TTE), and weekly physical activity in active university students.

Methods: Twenty-eight healthy, physically active university students (15 men, 13 women; age 22.1±2.5 years) completed a graded treadmill test (Bruce protocol) with gas analysis to determine VO2max and TTE. BOLT was measured as comfortable breath-hold time after normal exhalation. Weekly physical activity was assessed using the Godin Leisure-Time Exercise Questionnaire (GLTEQ). Spearman correlations examined associations between BOLT, VO2max, TTE, and GLTEQ. A multiple linear regression tested whether VO2max, TTE, age, height, weight, and GLTEQ predicted BOLT.

Results: BOLT times did not significantly differ between sexes. BOLT scores showed no strong correlation with VO2max (ρ=0.31, P=0.10), TTE (ρ=0.27, P=0.16), or GLTEQ (ρ=0.05, P=0.59). Regression analysis (R²=0.22, P=0.46) identified no significant predictors of BOLT.

Conclusions: In active young adults, the BOLT breath-hold test was not significantly associated with VO2max, endurance time, or self-reported exercise levels. These findings suggest that BOLT - a measure of breathing function and CO2 tolerance - does not serve as a surrogate indicator of aerobic capacity or habitual physical activity in this population. BOLT should be interpreted with caution if used for fitness assessment, as it appears to reflect a distinct aspect of physiological function not captured by standard aerobic performance tests.

Background: The effects of caffeine mouth rinsing on cognitive performance using a field-based approach have not yet been investigated. This study aimed to examine the effects of caffeine mouth rinsing on tennis targeting performance in young male recreational tennis players.

Methods: In total, 16 recreationally active young male tennis players (mean age: 22.03±1.74 years) were enrolled in this randomized, double-blind, placebo-controlled, crossover study. Test of groundstroke depth (TGD), test of groundstroke accuracy (TGA), test of volley depth (TVD), test of serve (TS) and tennis targeting performance (TTP), was assessed using the International Tennis Number (ITN) test. Interventions included 20 seconds of caffeine mouth rinsing (CMR: 300 mg/25 mL), placebo (PLA: 25 mL water), and a no-rinse control (CON) before each section of the ITN test. Data were analyzed using repeated measures ANOVA and Bonferroni post hoc tests, with a significance level of P≤0.05.

Results: Repeated measures ANOVA revealed a significant time-dependent difference in total tennis targeting performance scores obtained from the ITN test (P<0.01). Bonferroni post-hoc tests revealed that CMR significantly increased TGA, TVD and TTP scores. TTP points were increased in CMR group in a comparison with the PLA (147.06±26.23 vs. 130.25±20.38, P<0.001) and CON (147.06±26.23 vs. 129.19±22.27, P<0.01). TTP test scores were similar between PLA and CON (130.25±20.38 vs. 129.19±22.27, P>0.05).

Conclusions: Based on the total scores obtained from the ITN tests, the CMR intervention was found to improve tennis targeting performance in recreationally active tennis players.

Alcohol consumption represents the leading cause of death and disability under the age of 24. Among the most frequent physical problems there is certainly musculoskeletal damage. This creates problems in carrying out physical activity and sports. The aim of this narrative review is to assess the size of the problem of alcohol consumption and sport, the motivations and possible solutions. This narrative review is based on a detailed analysis of the scientific literature published before June 30^th, 2024 (PubMed, Web of Science, Scopus, Google Scholar). In sporting contexts there is a higher consumption of alcoholic beverages than in the general population. Alcohol is used during moments of socialization or during the celebration of some event or anniversary. Through sponsorship, alcohol is associated with success, beauty and even health. Alcohol consumption is not compatible with sporting activities. It reduces its positive effects and limits its quality. Moreover, alcohol induces muscle, bone and brain damage. Sports clubs have a duty to address the alcohol problem. It is mandatory, on the one hand, early identification of athletes who have risky alcohol consumption and on the other, promoting education initiatives on correct lifestyles with the involvement of the community to which they belong. It is also appropriate promote with force laws that prohibit the association of alcohol consumption to sport.

Background: This study examined the influence of two aerobic fitness indices (VO2max and [%4mM] i.e. the relative intensity [%VO2max] corresponding to a blood lactate concentration of 4 mmol·L^-1) on the recovery of power output during repeated sprinting.

Methods: Thirty female team players (age: 21.9 [2.9] y, body mass: 61.7 [5.4] kg, mean [standard deviation, SD]) took part in the study. VO2max and %4mM were assessed, and participants were divided into two groups in a cross-sectional design [well-trained (N.=15) or moderately trained (N.=15)] according to either VO2max (53.6 [3.4] vs. 47.6 [2.4] mL∙kg∙min^-1, P<0.001) or %4mM (86.7 [3.8] vs. 77.9 [4.1] %, P<0.001). Participants performed two 30 s sprints interspersed with 2 min of rest on a non-motorized treadmill. Blood samples were taken at rest, pre- and immediately post-sprinting for lactate, pH, ammonia, and plasma volume determination.

Results: When groups were separated according to %4mM, well-trained participants demonstrated superior recovery of peak and mean power output (PPO: 86.2 [10.3] vs. 74.5 [6.8] %, P<0.001; MPO30: 84.0 [7.8], vs. 77.1 [5.2] %, P<0.001), respectively]. When groups were separated according to VO2max, there were no differences in the recovery of PPO (82.8 [10.1] vs. 77.7 [10.5] %, P=0.188) and MPO30: (82.6 [6.5] vs. 78.9 [8.1] %, P=0.186). Blood metabolic responses were similar in all conditions (P=0.220-0.604).

Conclusions: The results suggest that %4mM is the most important aerobic fitness index for power output recovery during repeated sprint running.

Background: Body image refers to a person's perception of her/his own body. Currently, the media and most of the social settings place significance on having a thin body. The purpose of this study was to investigate the relationships between body image perception and satisfaction and some lifestyle-related factors such as weight status, sedentary habits and engagement in physical activity among sport athletes, gym practitioners and inactive individuals.

Methods: An observational study with a cross-sectional design was carried out. An electronic questionnaire was used to assess participants' characteristics and engagement in physical activity. Perception and satisfaction of body image were assessed using Stunkard's figures.

Results: One hundred-and-five (33.5%) of the participants were inactive, 107 were gym practitioners and 101 practiced different sport disciplines. The inactive group had a higher percentage of participants desiring to be thinner and a lower percentage desiring to be bigger, while the athlete group had a higher percentage expressing satisfaction with their current body image. Body satisfaction was found to be related with training volume.

Conclusions: This study highlights the significant associations between body image perception, satisfaction, and lifestyle factors such as physical activity levels and sedentary habits. Athletes reported greater body satisfaction compared to inactive individuals, emphasizing the potential role of regular physical activity in fostering a positive body image. These findings underscore the importance of promoting active lifestyles to improve both physical and psychological well-being.

Background: Despite growing interest in women's physiology in exercise sciences, the understanding of female athletes' energy metabolism remains limited. This study aimed to analyze substrate oxidation in response to energetic stimuli in female athletes using or not hormonal contraceptives, and to determine the influence of the estradiol-to-progesterone ratio fluctuations on energy metabolism.

Methods: Body composition (dual-energy X-ray absorptiometry), energy expenditure and substrate oxidation rates (resting, low-intensity walking exercise (4 km/h), and postprandial conditions; indirect calorimetry) were assessed among 32 athletes (23±3 years) during a high-training load period, in athletes using or not hormonal contraceptives (nine and 23, respectively). Athletes not using hormonal contraceptives were tested during high and low estradiol-to-progesterone (salivary samples) ratio conditions.

Results: No significant differences in energy metabolism at rest, whether fasting or postprandial, were observed between groups. During low-intensity exercise, a significantly higher net energy cost was observed in athletes using hormonal contraceptives (vs. high [P=0.01] and low [P=0.02] estradiol-to-progesterone ratio conditions). Higher carbohydrate (P=0.001) and lower lipid (P=0.005) oxidation rates were observed in the low estradiol-to-progesterone ratio condition compared with the high one in women not using hormonal contraceptives.

Conclusions: Thus, endogenous and exogenous ovarian hormones may influence energy metabolism during low-intensity exercise in female athletes under high-training loads.

Background: Optimal athletic performance requires balancing training with adequate recovery and energy intake. Failure to do this can result in low energy availability (LEA). This study investigated the prevalence of LEA and burnout syndrome in an athletic population and explored potential relationships between these conditions.

Methods: In this cross-sectional study, online surveys including two validated questionnaires (LEAF-Q and ABQ) and questions relating to LEA risk factors were distributed via email and social media. 139 females (39±13 years, 1.67±0.11 m, 68.0±17.8 kg, 24.4±6.4 kg/m² BMI) completed the survey. Participants were categorized as either at risk or not at risk of LEA based on their LEAF-Q scores.

Results: Eighty-nine female athletes (64%) were categorized as at risk of LEA. There was no significant relationship between LEAF-Q and ABQ scores, nor significant difference between athletes categorized as at risk and not at risk of LEA in sleep, dietary habits, perceived pressure to perform, and training history.

Conclusions: Risk of LEA was widespread in this heterogeneous female athletic population. There were no relationships between LEA and burnout, suggesting that despite overlapping symptoms, pathways are independent, or these questionnaires measure different parameters. Understanding the distinction between burnout and LEA is critical, and properly diagnosing the specific condition is key to effective management. This will ensure that interventions are appropriately tailored to address the correct issues, thereby optimizing recovery and performance.

Background: To investigate the effectiveness of the application of deep heat cream (DH) on the skin prior to aerobic exercise.

Methods: A total of 15 healthy male participants (age: 24.40±2.26 years, height: 1.70±0.08 m, weight: 64.73±8.66 kg, Body Mass Index: 22.28±1.94 kg/m^-2, maximal oxygen consumption [VO2max]: 30.11±6.41 mL/kg^-1/min^-1) volunteered for this study. Participants were required to attend three sessions 1) cycling VO2max test conducted to determine their 80% VO2max; 2, 3) cycling at 80% of VO2peak workload till exhaustion with either treatment application of DH or placebo cream (PC) on lower extremities of body. Time-to-exhaustion (TTE), heart rate (HR) and rate of perceived exertion (RPE) were recorded throughout the study.

Results: Results indicated significant differences between treatments for TTE (DH: 487.00±143.68 s vs. PC: 403.80±123.66 s, P=0.02); average RPE (DH: 15.82±1.82 vs. PC: 14.31±1.39, P=0.01). There were positive significant correlations between treatments for average HR (DH: 163.76±13.55 beats·min^-1 vs. PC: 158.42±31.76 beats·min^-1, r=0.58, P=0.02); last stage HR (DH: 176.87±15.29 beats·min^-1 vs. PC: 174.93±16.67 beats·min^-1, r=0.80, P=0.00).

Conclusions: Deep heat application before exercise has shown to significantly improve endurance performance. Athletes or sports enthusiasts may consider using deep heat before exercise to achieve optimal endurance performance. More studies are needed to explore the benefits of deep heat application during exercise performance.