Journal of Sports Medicine and Physical Fitness最新文献

Introduction: To systematically analyze the effect of diet combined with exercise intervention on blood glucose control in patients with type 2 diabetes.

Evidence acquisition: Six databases including PubMed, The Cochrane Library, Web of Science, EMBASE, MEDLINE and CNKI were searched from establishment to September 2024. Randomized Control Trial (RCT) articles that met the inclusion and exclusion criteria were screened. Meta-analysis was performed using Review Manager 5.3 software. The quality of the literature was assessed using the Cochrane Handbook of Systematic Reviews. Subgroup analysis and sensitivity analysis were used to find the source of heterogeneity.

Evidence synthesis: Sixteen studies were included, with a total of 7212 patients with type 2 diabetes. There were 3678 cases in the intervention group and 3534 cases in the control group. The results of meta-analysis showed that dietary combined exercise intervention significantly improved fasting blood glucose (MD=-0.39, 95% CI: -0.72~-0.06, P=0.02) and 2-hour postprandial blood glucose (MD=-1.67, 95% CI: -3.62~0.27, P=0.09), glycosylated hemoglobin, HbA1c (MD=-0.49, 95% CI: -1.27~-0.33, P<0.001), body weight (MD=-2.47, 95% CI: -4.82~-0.13, P=0.04), body mass (MD=-3.64, 95% CI: -4.07~-3.21, P<0.001), SBP (MD=-2.1, 95% CI: -4.30~0.28, P=0.09), DBP (MD=-0.93, 95% CI: -1.88~0.02, P=0.05), total cholesterol (MD=17, 95% CI: -0.02~0.35, P=0.07), triglyceride (MD=-0.08, 95% CI: -0.15~-0.01, P=0.03), QOL (MD=3.83, 95% CI: 0.69~6.98, P=0.02). Body Mass Index (BMI) (MD=-0.4, 95% CI: -0.32~0.24, P=0.79), waist circumference (MD=-1.4, 95% CI: -4.94~1.25, P=0.24), HDL (MD=-0.02, 95% CI: -0.08~0.03, P=0.43), LDL (MD=12, 95% CI: -0.37~0.61, P=0.63) may be due to insufficient patient compliance, short intervention time, or insufficient study sample size to detect significant improvement.

Conclusions: Diet combined with exercise intervention has significant effect on blood glucose control in patients with type 2 diabetes, and can significantly reduce HbA1c, fasting blood glucose, 2 h postprandial blood glucose, body weight, body mass, total cholesterol, triglyceride, SBP, DBP and QOL. Therefore, it is recommended that exercise combined with dietary intervention for at least 3 to 6 months can better improve the blood glucose indicators in patients with type 2 diabetes.

Background: Medial Tibial Stress Syndrome is associated with the stiffness of flexor digitorum longus (FDL) muscle. Therefore, it is necessary to reduce the load on FDL. Stretching has been reported to immediately reduce muscle stiffness and decrease maximal muscle strength. Thus, stretching the FDL may reduce its stiffness and stress. Additionally, the decrease in muscle strength due to stretching may be compensated by other cooperative muscles. This study aimed to determine how selective stretching of the FDL before exercise affects the stiffness of the FDL and its cooperative muscles after exercise.

Methods: Twenty-one healthy young men were enrolled in this crossover study. The elastic modulus of the FDL, tibialis posterior (TP), soleus, and flexor hallucis longus muscles were measured. The intervention trial involved selective stretching of the FDL. Subsequently, an eccentric ankle inversion exercise was performed, and the elastic modulus of each muscle was measured. The control trial consisted of resting in a sitting position instead of stretching.

Results: A significant interaction was observed for the elastic modulus of the FDL, the elastic modulus increased significantly only in the control trial after exercise. A main effect of timing was found only for the TP, and neither a main effect nor an interaction effect was found for any of the other muscles.

Conclusions: Selective stretching of the FDL muscle before exercise prevented an immediate increase in its stiffness after exercise, but there was no such effect following changes in muscle stiffness caused by exercise in the other cooperative muscles.

Background: Although the relationship between pride, moral disengagement, and social behavior has been investigated and the importance of transformational leadership has been highlighted in prior studies, little effort has been made to examine the relationship between transformational leadership and social behavior.

Methods: In order to better understand this, we tested the mediating effects of pride and moral disengagement on the relationship between transformational leadership and social behaviors. We recruited 296 elite athletes registered in the Korean sport and Olympic Committee.

Results: Structural equation modeling was performed to test the hypotheses. Despite the nonsignificant direct effect, transformational leadership had significant indirect effects on antisocial behavior towards teammates and opponents mediated by authentic and hubristic pride. Further, moral disengagement showed negative mediation effects on prosocial behaviors towards opponents and positive mediation effects on antisocial behaviors towards teammates and opponents.

Conclusions: Our study supported a full mediation model of transformational leadership, pride, moral disengagement, and social behaviors. These extends theoretical approaches of the transformational leadership theory and as the empirical research model conveys important implications in competitive sport situations.

Background: Ultra-trail running is increasingly popular, yet most research on biomechanics focuses on road running or treadmills. This study assesses changes in foot strike pattern (FSP), step frequency, and other biomechanical parameters over a 156-km ultra-trail race.

Methods: Fifty-five experienced runners participated in the Trail Scientifique de Clécy, a 156-km race with 6000 meters of elevation gain. Biomechanical data were collected at the end of each 26-km lap using video for FSP and Optojump for other parameters. Muscle strength was measured via maximal voluntary isometric contraction (MVIC) of the hip abductors and ankle plantar flexors.

Results: Forty-one runners completed the race. FSP remained consistent. Step frequency decreased initially (P=0.003) before stabilizing. Self-selected speed declined by 14.2% (P<0.001), and step length reduced by 12.6% (P<0.001). Ground contact time increased (+12.9%, P<0.001), while flight time remained stable. Leg stiffness showed a non-significant decreasing trend (P=0.048). MVIC for hip abductors and ankle plantar flexors slightly decreased late in the race (P=0.015 and P=0.004).

Conclusions: Experienced ultra-trail runners maintain consistent FSP while strategically adapting other biomechanical parameters to manage fatigue, supporting sustained performance and injury prevention in ultra-endurance races.

Background: The aim of this study was to explore the effects of underwater breathing-holding training on the cardiovascular function and swimming performance of athletes.

Methods: Sixty swimming athletes from sports colleges are separated into an experimental group and a control group, with 30 athletes in each one. Two groups undergo 8 weeks of swimming training with a total of 32 lessons. The control group athletes receive routine swimming training. The experimental group adds breath-holding training during swimming training. Before and after training, cardiopulmonary function tests are conducted on the two groups, including heart rate, lung capacity, blood pressure, and breath-holding time. Meanwhile, the maximum suction pressure, suction flow rate, and maximum ventilation volume of the athletes are tested before and after the experiment. In addition, the study also adds a 50m freestyle swimming test to explore the swimming performance of two groups before and after training.

Results: After 8 weeks, the overall improvement effect of the experimental group was more significant. In the cardiopulmonary function test, the lung capacity of the experimental group athletes increased from 3.24±1.69L to 4.81±1.93L, with statistical significance (P<0.05). For the control group, the lung capacity before and after the experiment did not exhibit statistically significant difference (P>0.05). Meanwhile, the heart rate of the experimental group athletes decreased from 58.61±9.32 beats/minute to 56.39±8.28 beats/minute, with a P value of only 0.1668, lower than that of the control group's 0.4412. In addition, the breath-holding time of the experimental group increased from 54.36±2.05 s before the experiment to 60.15±3.28 s (P<0.05). In the index tests of maximum suction pressure, suction flow rate, and ventilation volume, the experimental group had statistically significant differences before and after the experiment (P<0.05). The control group only had statistical significance in maximum suction pressure and suction flow rate. In addition, the 50m freestyle swimming time of the experimental group athletes was reduced from 25.52±0.59 s to 25.20±0.66 s (P<0.05). The free swimming performance of the control group before and after training was not statistically significant (P>0.05). The results of lung CT examination showed that the lung function of the experimental group athletes significantly improved. The lung imaging images showed larger lung volume, unobstructed airway, clear alveolar structure, and no obvious lung lesions or atrophy.

Conclusions: The combination of breath-holding training and routine training in swimming training can improve the cardiovascular function of athletes, enhance their respiratory function, and ultimately enhance their swimming performance. This training method provides a scientifically effective training strategy for swimmers.

Background: Asymmetry of propulsion is a key factor when the movements of two limbs occur in sequence. Considering the difficulties in quantifying thrust forces during free-swimming, tethered-swimming is proposed as an alternative tool. The purpose of this study was to investigate the thrust forces during tethered and free-swimming, including the effect of hand dominance.

Methods: Eleven swimmers were analyzed during 10-s all-out front-crawl swimming test in both conditions using only arms. Two pressure sensors were attached to each swimmer's hand (palmar and dorsal side) to estimate the propulsive forces as the horizontal component of the product of hand differential pressure and hand surface. Propelling forces in terms of average (FMEAN), impulse (I), peak (FPEAK), and as a pattern within the stroke cycle values were analyzed.

Results: Larger hand propulsion was found in tethered than in free-swimming (~16%, 11%, and 21%, for FMEAN, FPEAK, and I, respectively). The SPM analysis highlighted larger values only at the beginning of the cycle (from 7% to 42%). Dominance analysis revealed a higher FPEAK (~12 N) in the dominant limb than in the nondominant limb in both swimming conditions.

Conclusions: Larger hand force in tethered than free-swimming conditions is explained by differences from entry to catch phase.

Background: Mass participation in amateur cycling events is popular, and ensuring participant safety is crucial. This study aimed to determine the epidemiology of medical encounters (MEs), including injury and illness, at mass-participation amateur cycling events and to explore associated risk factors.

Methods: We conducted a cross-sectional, descriptive, exploratory analysis of operational data collected during the 2015-2016 94.7 Ride Joburg cycling race. Outcomes include frequency (N., %), prevalence (%), incidence (injuries/1000 participants), did-not-finish (DNF, %), and Odds Ratio (OR, 95%CI).

Results: In total, 44849 individuals, mean age 40.06±11.68, participated in the 94.7 Ride Joburg cycling race during 2015-2016. We report the prevalence for MEs (5.3%) (injury: 1.7%, illness: 3.6%). The incidence of all MEs was 52.71 (50.61-54.88) (injury: 16.79 [15.61-18.03], illness: 35.92 [34.19-37.72]). Most race participants were male (79.0%), aged 31-50 (58.9%). Older age decreased the odds of injury, illness, or not finishing (P<0.001). Females had higher odds of injury (OR:1.43; 1.21-1.67; P<0.001) and for DNF (OR:1.57; 1.46-1.70; P<0.001) but lower odds of illness (OR:0.73; 0.64-0.64; P<0.001), compared to males. Overall, 7.9% of participants DNF, 6.9% had MEs, 3.2% were injured, and 3.8% were ill. Medical point location and distance were not significantly associated with medical encounters.

Conclusions: Older participants have lower odds of injury and illness encounters. Females have higher odds of injury encounters and not finishing the race but lower odds of illness encounters than males. These findings offer insights into injury and illness at mass-participation amateur cycling events.

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.

Background: This study analyses whether sweep rowers (port, starboard), who in the boat row in an asymmetric movement, sit on the seat of the rowing ergometer in a different manner from scullers, who on the boat row in symmetric manner.

Methods: Twenty-five male rowers (9 scull and 16 sweep: 8 port and 8 starboard) each performed a 90-min endurance training on rowing ergometer. Any displacement sideways of the rowers on the seats was measured from images of back of the rower at 30, 60 and 90 min.

Results: Scullers were seated in the expected manner maintaining centrality of the seat (distance from center at 30, 60, 90 min = 0.3±0.5 cm; 0.3±0.5 cm, 0.6±0.5 cm) in contrast with portside rowers who shifted to the left (30, 60, 90 min = -3.0±1.1 cm; -3.6±1.1 cm; -3.5±0.9 cm) and starboard rowers who shifted to the right (30, 60, 90 min = 3.1±2 cm; 3.9±1.6 cm; 3.4±1.4 cm). Shifted seating for sweep rowers was consistently observed to the opposite side to which they rowed.

Conclusions: The type of rowing on the boat influenced how rowers sit on the ergometer with sweep rowers consistently adopting a seating position shifted to opposite side to the one they rowed. This can be interpreted in terms of neural memory of prior postural adjustments and calls for further monitoring as asymmetry in seating may lead to uneven loading, particularly relevant to athletes with large training volume and density and when rowing in more "extreme" rowing settings, for example, coastal rowing / beach sprints events.

Introduction: This study evaluated and quantified the effects of plyometric training (PT) on soft versus rigid surfaces on jump, sprint, and agility performance.

Evidence acquisition: A literature search was conducted using PubMed, CINAHL, Embase, SportDiscuss, and Web of Science from January 1980 to April 2024. Randomized controlled trials examining PT interventions on the lower limbs with surface descriptions were included. Data extracted by two independent reviewers comprised: 1) the name of the first author and year of publication; 2) study design and participant characteristics; 3) PT program details; and 4) main outcome measures.

Evidence synthesis: The meta-analysis revealed that soft-surface PT significantly increased the vertical jump height (standardized mean difference [SMD], 0.83; [95% confidence interval [CI] 0.59, 1.07]), while rigid-surface PT also produced significant improvements in jump height (SMD, 0.98; [95% CI 0.68, 1.28]). For horizontal jump performance, soft-surface PT showed significant effects (SMD, 0.96; [95% CI 0.64, 1.27]), while rigid-surface PT demonstrated moderate effects (SMD, 0.78; [95% CI 0.5, 1.05]). Both soft- and rigid-surface PT significantly reduced sprint time (SMD, -1.03; [95% CI -1.24, -0.81] and SMD, -0.89; [95% CI -1.22, -0.57], respectively) and enhanced agility performance (SMD, -1.07; [95% CI -1.34, -0.80]).

Conclusions: PT significantly enhanced physical performance outcomes, regardless of the surface type. Practitioners may not need to prioritize the specific surface type when implementing PT programs aimed at improving jump, sprint, and agility performances.