This study aims to identify the relationship between jump height and the kinetic and kinematic parameters of the hip, knee, and ankle joints during countermovement jump (CMJ) in elite male athletes. Sixty-six elite male athletes from various sports (strength and power, winter downhill, combat, ball game, and aquatic) performed maximal effort CMJs with hands and arms crossed against their chests on force platforms. Jumping motion in the sagittal plane was recorded using video analysis and the peak torque, power, and angular velocity of the right hip, knee, and ankle joints were calculated during the propulsive phase. Correlations between the CMJ height and kinetic and kinematic parameters were investigated using Pearson's product-moment coefficient (r) and Spearman's rank correlation coefficient (ρ). CMJ height was highly correlated with peak hip power (ρ = 0.686, p < 0.001) and peak knee angular velocity (r = 0.517, p < 0.001), and moderately correlated with peak hip angular velocity (r = 0.438, p < 0.001) and peak hip torque (r = 0.398, p = 0.001). These results indicate that notable hip torque and power can contribute to increased angular velocity in both the knee and hip joints, ultimately increasing the CMJ height in elite male athletes.

Studies have not adequately addressed the influence of fatigue, which is considered a major risk factor for hamstring injuries. Therefore, this study aimed to clarify how a muscle fatigue condition affects the success of hamstring injury prevention programs in sprinters. The study subjects were 613 collegiate male sprinters. They employed submaximal/maximal running for a large number of runs and supramaximal running for a small number of runs in daily training. The hamstring injury prevention program had become the most effective strategy in the past 24 seasons of track and field for preventing hamstring injuries. The number of sprinters who experienced hamstring injuries in three periods over the 24 seasons was recorded. The incidents of hamstring injuries during supramaximal running per athlete-seasons were 137.9, 60.6, and 6.7 for Periods I, II, and III, respectively, showing a significant decline (p < 0.01). Furthermore, the incidents of hamstring injuries during submaximal and maximal running per season showed no significant change. The results of this study indicate that by inducing muscle fatigue, a small number of runs makes hamstring injury prevention programs effective.

There are only few records of physical fitness data for athletes. This study aimed to explore the secular trends in physical fitness data of student athletes and the relationship of fitness parameters with the results of intercollegiate sports competitions. We used the physical fitness data of male students belonging to the Juntendo University Athletics Club from 1999 to 2019. The analysed parameters were height, weight, chest circumference, skinfold thickness, grip strength, vertical jump, sidestep, and sit and reach test. The ekiden results were examined in relation to data on medium- and long-distance activities with reference to the ranking. The study results suggested no difference in the skinfold thickness of the upper extremity across the events, except for throwing events. Grip strength declined gradually in sprints, hurdles, and jumping events, while it was high in throwing events. Vertical jump records declined over time in all events and remained at low levels in middle- and long-distance events. Sidestep improved among males in the general population, while it remained the same among all athletes. A relationship was found between grip strength and vertical jump, which are indices of muscle strength and power, and competitive results obtained in middle- and long-distance races.

This study aimed to examine the combined effect of voluntary exercise and screen time during the first wave of the coronavirus disease 2019 (COVID-19) restrictions on subsequent grip strength among health and sports science students in Japan. The participants performed grip strength tests and had their weight assessed on 21 October 2020. Furthermore, they completed an online survey between 21 October and 28 October 2020, which included participants’ current age, height, voluntary exercise, and screen time during the first wave of the COVID-19 pandemic (April and May 2020). In total, 380 participants provided complete data (mean age ± standard deviation [SD]: 18.8 ± 0.6 years; 233 males). Our results revealed that 87.6% of male students and 84.4% of female students performed voluntary exercise >1 day/week during the first wave of the pandemic. Moreover, 21.5% of male students and 23.1% of female students had >8 h/day of screen time. A trend toward greater grip strength was observed for both male and female students with high voluntary exercise and low screen time. In particular, grip strength (p < 0.05) was significantly greater in male students with high voluntary exercise and low screen time than those with low voluntary exercise and high screen time. In conclusion, this study revealed that during the first wave of COVID-19 restrictions, a combination of high voluntary exercise and low screen time positively affected the subsequent grip strength of health and sports science students.

Background: Periodontal disease is prevalent among elite athletes globally, yet its status in Japanese athletes remains unclear. This study assessed periodontal risk in Japanese university athletes and its association with oral health-related quality of life (QOL), sports performance, and immune status. Methods: A cross-sectional study was conducted with 313 university athletes (basketball, volleyball, athletics). Periodontal risk was evaluated using a Trypsin-Like Peptidase activity assay (TLP-AA) kit; a score ≥ 1.5 indicated the presence of Red Complex bacteria (positive risk). Participants completed the Oral Impacts on Daily Performance (OIDP), Oslo Sports Trauma Research Centre (OSTRC) overuse injury, and Immune Status Questionnaires (ISQ). Results: Positive periodontal risk was identified in 25.9% (81/313) of athletes. While overall prevalence was not statistically different from the general population (17.8%), specific associations emerged. Positive risk was significantly associated with “pain related to sports” (OSTRC) overall (p = 0.016) and specifically in males (p = 0.004). Among track and field athletes, positive risk was associated with difficulty “smiling/laughing” (OIDP, p = 0.033) and lower self-rated general health (p = 0.032) and immune functioning (p = 0.047). Conclusions: Periodontal risk is notable in Japanese university athletes and is significantly associated with sports-related pain and specific QOL domains. Regular oral health monitoring may be crucial for maintaining athletic performance and well-being.

Article: Relationship between various jumping and sprinting abilities in Japanese elementary school children - Gazzetta Medica Italiana - Archivio per le Scienze Mediche 2022 July-August;181(7-8):496-501 - Minerva Medica - Journals