Journal of Sports Medicine and Physical Fitness最新文献

Background: The aim of this study was to examine the specific characteristics of injuries (injury location, injury type, and time to return to sports) based on sex and rowing style.

Methods: We included 60 adolescent rowers (Sweep male and female, 12 respectively; Sculling male and female, 18 respectively) who underwent training in Korea from January to December 2023. Sports injuries were meticulously recorded using the Daily Injury Report form issued by the International Olympic Committee for rowers characteristics (sex, rowing style) and injury characteristics (injury location, injury type). The injury incidence rate (IIR) per 1000 h of training was calculated using the 95% Poisson Confidence Interval. A χ² test was performed to compare the characteristics of the rowers and injury characteristics.

Results: The overall IIR was 4.25 injuries per 1000 training hours. The IIR was lower for men than for women (P<0.001). However, sweep and sculling were similar (P=0.269). There was a difference in the affected body regions according to the sex and rowing style (P=0.028, P=0.005; respectively). Time to return to sports varied between rowing styles (P=0.049) and sexes (P=0.033), and it also differed in sweep (P=0.002) and sculling (P=0.045) depending on body regions.

Conclusions: These results should be incorporated into programs that are aimed at improving the performance of these rowers and preventing sports injuries. In addition, can be used as data to determine their return to sport.

Background: Exercise training may reduce whole-body fat mass and percentage. However, whether exercise improves fat distribution assessed by fat mass ratio (FMR) and regional fat percentage in men living with HIV (MLHIV) is still unclear. The aim of this study was to compare the FMR and total and regional body fat between physically active and inactive MLHIV and HIV-uninfected men.

Methods: Using a cross‑sectional design, total and regional body fat assessed by dual x-ray absorptiometry (DXA) were compared between 19 MLHIV (ACT-MLHIV, 52±7 y, 23.8±4.1 kg.m^-2) enrolled in a multimodal training program (aerobic, strength and flexibility exercises) for at least 12 months (60‑min sessions; 3 times/wk with moderate intensity) vs. 19 inactive MLHIV (IN-MLHIV, 51±7 y, 25.9±3.3 kg.m^-2) and 19 HIV-uninfected men (HIV-, 51±8 y, 26.0±3.3 kg.m^-2). FMR was calculated as the ratio between the percentage of fat in the trunk and the lower limbs.

Results: The ACT-MLHIV showed a lower trunk fat percentage (24.1±17.9% vs. 34.4±11.9%; P=0.02) and FMR (1.5±0.6 vs.1.9±0.5; P=0.02) than the IN-MLHIV, with no difference between them in lower limbs fat percentage (IN-MLHIV: 16.3±5.9 vs. ACT-MLHIV: 15.9±9.6%; P=0.98). HIV- showed a lower FMR (1.2±0.2; P<0.02) and superior lower limb fat percentage (24.1±8.0%; P<0.0001) than IN-MLHIV and ACT-MLHIV, as well as a higher total fat percentage than ACT-MLHIV (27.3±6.2 vs. 21.8±6.9%; P=0.02).

Conclusions: Physical exercise seems to attenuate HIV-associated lipodystrophy by reducing trunk fat percentage while preserving lower limb fat mass. FMR and total fat percentage should not be used alone as markers of exercise-induced changes in lipodystrophy.

Background: Low back pain is prevalent among various populations and greatly impacts their quality of life. Professions that incorporate several working hours combined with heavy labor are the most affected. The aim of this study was to examine the effects of an 8-week core training intervention in emergency personnel.

Methods: Sixteen randomly selected male participants; police officers (N.=8) and firefighters (N.=8) (mean age: 40.75 years; mean height: 177.69 cm; mean body mass: 85.50 kg) performed various testing procedures that assessed core muscle strength and endurance and filled the Oswestry Disability Index Questionnaire regarding the level of low back pain before and after the intervention. The 8-week intervention consisted of two 45-60-minute sessions per week that included ten core-related exercises.

Results: Statistical analysis; paired samples t-test and Wilcoxon Signed-Rank Test, demonstrated significant effects in the 30-sec sit-up test, the Double Leg Lowering Test and the isometric abdominal strength measurements; p value level of significance was set at P≤0.05. All participants had minimal lower back disability before and after the intervention.

Conclusions: The results demonstrated that the prescribed regime could improve core strength and endurance in high-risk professionals. The most important finding is that training interventions for emergency personnel are most effective when they incorporate a variety of exercises that target the core musculature in all planes of movement and engage the whole range of motion.

Background: High-velocity concentric actions can be negatively impacted by cumulative fatigue during plyometric training. Reducing vertical ground reaction forces (GRF) upon landing could decrease eccentric demands, potentially minimizing fatigue, maintaining concentric performance, and benefiting concentric training adaptations. Therefore, this study examined the effect of intentionally higher and lower landing vertical GRF on the ability to sustain concentric jumping performance.

Methods: Twenty men (25.2±3.5 years) performed 30 maximal effort jumps over a 50 cm hurdle (high-landing GRF) and onto a 50 cm box (low-landing GRF), on two separate occasions in a counter-balanced order. Jumps were measured using two force platforms (one for takeoff and one for landing) and a linear position transducer. The 30 jumps were divided into 5 groups of 6 repetitions, and the mean value for each group was analyzed.

Results: There was no significant condition × repetition group interaction for any parameters, indicating that the greater landing GRF during hurdle jumps did not negatively affect concentric jump performance throughout the 30 jumps. Concentric velocities and jump height were significantly greater during box jumps compared to hurdle jumps.

Conclusions: Thirty maximal-effort jumps did not cause fatigue-related decrease of performance, independent of jump type (i.e., the magnitude of landing GRF). Although, reduced vertical GRF upon landing appears to have a neutral-to-positive effect on concentric jumping performance. Therefore, reducing landing GRF, such as by using BJs, could acutely augment jumping performance and help to reduce cumulative training load.

Background: Jumping and linear sprinting performances show a moderate correlation with change of direction (COD) ability. However, the extent of these correlations remains unknown through statistical analysis. Thus, this study statistically compared correlation coefficients between COD, COD deficit (CODD), and jumping and linear sprint performances.

Methods: National-level basketball (29) and baseball (18) intercollegiate female athletes performed 20-m linear sprint, proagility (5-10-5) test, squat jump (SJ), countermovement jump with (CMJarm) and without (CMJ) arm swing and modified reactive strength index (RSImod). Correlation analysis was used to assess factors correlated with COD performance and CODD; subsequently, correlation coefficient comparison test was used to determine better correlations with COD and CODD performance.

Results: CMJ (r=-0.483) and CMJarm (r=-0.446) had stronger correlations with 10-m COD (both, P<0.018) than with 10-m linear sprint (r=0.431, P=0.002). For 20-m COD, RSImod, CMJ, and CMJarm (r=-0.491--0.543, P<0.001) better correlated with 20-m COD than with 20-m linear sprints (r=0.436, P=0.002), while RSI (both r=-0.317, P<0.030) and SJ (r=-0.359, r=-0.293, P=0.046) were weakly correlated with 10- and 20-m COD. The differences in correlation coefficients for RSImod, CMJ, and CMJarm were not significant in both 10- and 20-m COD. Ten-meter linear sprint performance only correlated with 10-m CODD, while no correlation was observed with 20-m CODD.

Conclusions: Stronger correlations of RSImod, CMJ, and CMJarm with 10-/20-m COD than with linear sprinting, RSI, and SJ suggest that training focused on improving countermovement and arm swings with jumping may enhance COD performance in female athletes.

Background: The countermovement jump (CMJ) is a reliable and valid test of lower-extremity (LE) muscle power and neuromuscular performance. Body mass is positively associated with CMJ performance in young adults, warranting the examination of the influence of body composition on jump height (JH). This study examined the mediation effects of body composition on CMJ performance in young adults. The hypothesis was that fat-free mass and percent fat mass would significantly mediate the association between body mass with JH in young adults.

Methods: Healthy young adults (N.=81; 47 female; mean age 25.1±3.4) completed this study and underwent body composition assessment using a bioelectrical impedance analysis device. Participants performed three CMJ trials to measure average JH using an electronic jump mat. Mediation analysis models were performed to examine the hypothesis of this study.

Results: The mediation analyses indicated that the indirect effects of fat-free mass on the association between body mass with JH were significant (indirect effect [IE]=-0.23, 95% CI -0.315, 0.767; IE=0.76, 95% CI 0.334, 1.272; respectively), after controlling for sex and percent fat mass.

Conclusions: The association between body mass with JH in young adults with normal BMI was mediated by fat-free mass. Clinicians, trainers, and coaches should potentially target increasing fat-free mass when improving LE power and neuromuscular performance in rehabilitation and sports settings in this population, but further studies are needed.

Introduction: Overuse injuries are common in sports involving jumping, running, and landing, due to the repetitive nature of these activities and the strain they place on the lower extremity. The objective of the study was to determine the role of strengthening exercises in the management of overuse sports injuries of lower extremity and its effects on prevention of injury recurrence.

Evidence acquisition: This study employed a systematic review design. The author extracted and reviewed the papers for this study in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria, and then used the PEDro scale to rate the articles' quality. For the most recent and well-developed primary data, several electronic databases including Google Scholar, PubMed Central, MEDLINE, Cochrane Library, and PEDro were exhaustively searched. Inclusion criteria were based on PICO (T) model and included study population, intervention nature, outcome measures, time period, methodological quality, and linguistic extent.

Evidence synthesis: The data synthesis involved analyzing randomized control/clinical trials on strengthening exercises for lower extremity overuse sports injuries in athletes, considering outcomes including muscle strength, pain scores, return to sports, and injury prevention.

Conclusions: The methodological quality of the recruited articles ranged from excellent to fair on PEDro scale. Three included studies investigated the effects of strengthening exercises on management of lower extremity injuries of athletes. Four studies evaluated its role on prevention from recurrence of injuries. This study has concluded that strength training plays a fundamental role in management and prevention of overuse injuries. It not only improves the muscle performance, fitness level, speed and agility in sports but also decreases the pain, and aids in early recovery from an injury.

Background: The purpose of this study was to comprehensively investigate and compare the architecture of the quadriceps muscle in football, taekwondo, and athletics, shedding light on potential differences and providing valuable insights for athletic training and performance enhancement.

Methods: Thirty-five athletes (football[N.]=14. [7 women, 7 men]; taekwondo [N.]=11. [6 women, 5 men]; athletics [N.]=10. [5 women, 5 men]) aged 17-21 years participated in the study. After participant demographic data were collected, 2D real-time B-mode ultrasound (USG) and right (R) and left (L) leg quadriceps muscle group rectus femoris (RF), vastus intermedius (VI), vastus lateralis, pennation angle (PA), RF cross-sectional area (CSA), and subcutaneous fat thickness were determined.

Results: In the study, in female athletes, R-RF+VI (P=0.04, ES:4.34), R-VI (P=0.01, ES: 6.1), R-RF: (P=0.009, ES: 7.9), R-CSA (P=0.04, ES: 5.2), L-RF (P=0.002, ES: 10.4) and L-CSA (P=0.007, ES: 7.7) significant differences were found in favor of the Football group. In male athletes, R-CSA (P=0.004, ES: 9.05), L-RF (P=0.05, ES: 3.5) and L-SFT (P=0.00, ES: 13.6), there was a significant difference in favor of the Football group. L-PA (P=0.009, ES: 6.2). L-PA (P=0.009, ES: 6.2) was significantly higher in the male Taekwondo group.

Conclusions: Our research findings show that there is a significant relationship between the type of exercise performed and the structural differences observed in the quadriceps muscle. Consequently, it is highly recommended to consider the outcomes of our study for enhancing the efficacy of training programs in the domains of football, taekwondo, and athletics.