Search Results (12)

Our previous study reported that male university rugby players tended to have a gut with a dysbiotic environment, characterized by abundant pathobiont bacteria and an accumulation of succinate, when compared with age-matched, non-rugby playing healthy males. In the present study, we conducted a randomized, double-blinded, placebo-controlled experiment to evaluate the potential of blackcurrant extract and/or partially hydrolyzed guar gum (PHGG) to improve the gut environment of university rugby players. Participants were supplemented with blackcurrant extract and/or PHGG or a placebo for 4 weeks. Beneficial gut bacteria such as Megasphaera spp. tended to increase (p < 0.10) and Bifidobacterium spp. increased (p < 0.05) with the intake of blackcurrant extract and/or PHGG. A subgroup analysis further indicated that, unlike in those with a eubiotic gut environment, the dietary supplements also increased the number of beneficial gut bacteria such as Phascolarctobacterium spp. (p < 0.10) and Faecalibacterium spp. (p < 0.10) and fecal SCFA concentrations (p < 0.05) in participants with a possible dysbiotic gut environment. However, a synergistic effect between blackcurrant extract and PHGG was not clearly observed. Although further investigation is recommended, it was concluded that blackcurrant extract and PHGG can at least be used as functional materials to improve gut dysbiosis in university rugby players. Full article

Objective: With the remarkable advances in diagnostic ultrasound equipment, there is a growing need for ultrasound diagnosis of muscle and soft tissue injuries in sports injuries. Among these, hamstring strains are often difficult to treat and require early and accurate diagnosis. Injuries to the proximal part of the hamstring often take a long time to heal. For this reason, the diagnosis of proximal hamstring injuries is extremely important. The structure of the origin tendon is characteristic, and it is a complex in which the semitendinosus muscle (ST) of the medial hamstring and the long head of the biceps femoris muscle (BFLH) of the lateral hamstring share a conjoint tendon (CT). On the other hand, the semimembranosus muscle (SM) attaches to the ischial tuberosity independently. In this study, we created a classification of injury sites focusing on the origin tendon, and investigated the distribution of injury location, relationship to the player’s position, and the detection rate of ultrasound diagnosis. Material and Methods: We used ultrasound and MRI to diagnose 52 university men’s rugby players who had suffered a hamstring strain for the first time and investigated the distribution of the injured areas. We performed an ultrasound scan as the initial diagnosis and used MRI as a final diagnostic tool. A classification focusing on the origin of the muscle was created. First of all, it was divided into two types: the BFLH-ST complex type, which originates in the CT, and the SM type, which originates in the SM tendon. We also classified BFLH-ST complex damage, including CT damage, as Type I, a BFLH injury without CT injury as Type II, and a ST injury without CT injury as Type III. We then investigated the distribution of the injury location. The degree of ultrasound detection in each injury type was evaluated in three grades. The frequency of BFLH complex and SM injuries was investigated in players who played the forward (FW) and back (BK) positions. Results: The distribution was 40 limbs (77%) for BFLH-ST complex injury type and 12 limbs (23%) for SM injury type. In the BFLH complex type,19 limbs which met the Type I classification criteria for CT tear, 19 limbs met the Type II, and 2 limbs met the Type III. FWs had a higher incidence of SM injuries and BKs had a higher incidence of BFLH-ST complex injuries. With regard to the detection of muscle injuries via ultrasound, a high rate of detection was possible, except for a slight injury to the myofascial junction of the BFLH. Discussion: In terms of the distribution, the BFLH-ST complex, which shares the same origin tendon (i.e. CT), had a higher frequency of muscle tears than the SM. In addition, CT junction injuries occurred frequently in Type II as well as Type I (=CT injury). One possible cause is that the CT is subject to concentrated traction stress from both the medial and lateral hamstrings. With ultrasound, the detection rate of muscle damage around the BFLH-ST complex and SM originating tendon was high, suggesting that it is useful as an initial diagnosis. From this, it can be said that ultrasound is also useful for primary evaluation of “proximal hamstring injury”, which is prone to severe and should be given a final diagnosis using MRI. Conclusions: We created a classification system focusing on the originating tendons and clarified their incidence rates. In this study, ultrasound was found to be useful in the detection of originating tendon injuries. We also identified the characteristic sonographic findings of each type. Full article

This study aimed to investigate the significance of baseline measurements for amateur team athletes playing contact and collision team sports with a specific focus on the Sports Concussion Assessment Tool (SCAT) to improve concussion management. Symptoms of sports-related concussions (SRCs) can be diverse and long-lasting and include cognitive impairment, sleep disturbances, and vestibular dysfunction. Therefore, comprehensive baseline data are essential to preventing recurrent concussions and secondary injuries. This study was conducted during the 2023 off-season and evaluated the baseline condition of 65 male university rugby players using the SCAT5, which includes self-reported symptoms, and the modified Balance Error Scoring System (mBESS). The athletes were assessed for the presence or absence of SRC, and the mean values were compared using the Mann–Whitney U test. Among the participants, 35.38% (23/65) reported symptoms, with an average of 1.5 ± 2.8 symptoms per player and an average symptom score of 2.66 ± 5.93. In the mBESS, no errors were observed in the tandem stance test; however, 72.31% (47/65) made errors in the single-leg stance test on the non-dominant foot, with an average of 1.7 ± 1.5 errors. Many athletes self-reported symptoms and balance errors, even during asymptomatic periods before experiencing concussion, indicating unresolved issues. In the injury history survey, the baseline evaluations and injury histories of the participants classified into the SRC and non-SRC groups were compared. In the mBESS single-leg stance test (non-dominant foot), 84.21% (32/38) of the SRC group participants made errors, with an average score of 2.13 ± 1.52, whereas 55.55% (15/27) of the non-SRC group participants made errors, with an average score of 1.15 ± 1.35, showing a significant difference (p = 0.007). Additionally, significant differences were observed in the average number of ankle sprains (p = 0.027) and fractures (p = 0.048) between patients with and without a history of SRC. These findings indicate that athletes may have underlying issues even during normal periods before concussion. Moreover, the results highlighted the impact of previous concussions on motor control and injury risk. This underscores the importance of preseason baseline measurements using the SCAT to identify at-risk athletes and implement preventive measures. These findings align with the recommendations of the 6th International Conference on Concussion in Sport and suggest further refinement of concussion assessment tools. Full article

Understanding the physical fitness elements that influence high-intensity running ability during rugby matches is crucial for optimizing player performance and developing effective training strategies. In this study, we aimed to investigate the relationships between various physical fitness components and high-intensity running ability in rugby. For this purpose, 60 Japanese university rugby players were randomized into four groups and two matches were played. The participants were monitored in two matches, and their running abilities were assessed using GPS sensors. The running time was divided into three running velocity categories: distance run at ≤5.4 km/h (low-intensity running); distance run at 5.5~17.9 km/h (medium-intensity running), and distance run at ≥18.0 km/h ≤(high-intensity running) and backs and forwards were evaluated separately. To determine which physical fitness test is more predictive of performance, we decided to correlate several physical test performances with the running time intensities during the matches. Independently of the position, the high-intensity running time correlated with the repeated sprint ability (RSA) and the 40 m sprint speed. The results suggest that RSA measured in the field is the most important high-intensity running ability predictor during a match for both positions. Full article

Delayed recovery of the core body temperature after exercise adversely affects physiological functions, and the effects of ingesting lower-temperature ice slurry on post-exercise recovery remain unclear. We investigated the effects of ingesting −2 °C ice slurry on physiological recovery after field-based rugby union training. Fifteen university rugby union players participated in our randomized controlled study. The players participated in the training for 60 min in a hot outdoor environment (wet-bulb globe temperature, 30.5 °C). Physiological responses were measured during a physical performance test performed after the players ingested either −2 °C-ice slurry (ICE, N = 7) at 5 g/kg body mass or a 30 °C-fluid (CON, N = 8) during the 15 min recovery period after the training. Tympanic temperatures and heart rates were measured as the physiological indices, as well as heat storage. The ICE group showed significantly decreased tympanic temperatures and heart rates (p < 0.05) during the recovery period and increased heat storage (p < 0.05) but did not show improvement of physiological indices during the performance test compared to the CON group. These results suggest that ingestion of −2 °C ice slurry in even lower amounts than those previously reported is useful for physiological recovery after training in hot outdoor environments. Full article

This study aimed to determine the effect of 3 mg.kg⁻¹ acute caffeine ingestion on muscular strength, power and strength endurance and the repeatability of potential ergogenic effects across multiple trials. Twenty-two university standard male rugby union players (20 ± 2 years) completed the study. Using a double-blind, randomized, and counterbalanced within-subject experimental design. Participants completed six experimental trials (three caffeine and three placebo) where force time characteristic of the Isometric Mid-Thigh Pull (IMTP), Countermovement Jump (CMJ) and Drop Jumps (DJ) were assessed followed by assessments of Chest Press (CP), Shoulder Press (SP), Squats (SQ), and Deadlifts (DL) Repetitions Until Failure (RTF at 70% 1 RM). ANOVA indicated that caffeine improved both the CMJ and DJ (p < 0.044) and increased RTF in all RTF assessments (p < 0.002). When individual caffeine trials were compared to corresponding placebo trials, effect sizes ranged from trivial-large favoring caffeine irrespective of a main effect of treatment being identified in the ANOVA. These results demonstrate for the first time that the performance enhancing effects of caffeine may not be repeatable between days, where our data uniquely indicates that this is in part attributable to between sessions variation in caffeine’s ergogenic potential. Full article

Previous studies on performance effects by New Zealand blackcurrant (NZBC) extract used mainly a single exercise task. We examined the effects of NZBC extract in a battery of rugby union–specific tests including speed, agility and strength testing. University male rugby union players (n = 13, age: 21 ± 2 years, height: 182 ± 6 cm, body mass: 87 ± 13 kg) completed two full familiarisations and two experimental visits in an indoor facility. The study had a double blind, placebo-controlled, randomised, crossover design. For the experimental visits, participants consumed NZBC extract (210 mg/day of anthocyanins for 7 days) or placebo with a 7-day wash-out. Testing order was the running-based anaerobic sprint test, the Illinois agility test, seated medicine ball (3 kg) throw, and handgrip strength. With NZBC extract, there may have been an effect for average sprint time to be faster by 1.7% (placebo: 5.947 ± 0.538 s, NZBC extract: 5.846 ± 0.571 s, d = −0.18 (trivial), p = 0.06). However, with NZBC extract there may have been reduced slowing of sprint 2 (d = −0.59 (moderate), p = 0.06) and reduced slowing for sprint 6 (d = −0.56 (moderate), p = 0.03). In the Illinois agility test, there may have also been an effect for the mean time to be faster by 1.6% (placebo: 18.46 ± 1.44 s, NZBC extract: 18.15 ± 1.22 s, d = −0.24 (small), p = 0.07). The correlation between the %change in average sprint time and %change in mean agility time was not significant (Pearson R² = 0.0698, p = 0.383). There were no differences for the seated medicine ball throw distance (p = 0.106) and handgrip strength (p = 0.709). Intake of NZBC extract in rugby union players seems to improve tasks that require maximal speed and agility but not muscle strength. NZBC blackcurrant extract may be able to enhance exercise performance in team sports that require repeated movements with high intensity and horizontal change of body position without affecting muscle strength. Full article

The aim of this study was to investigate the effect of ingestion of ice slurry before bedtime on the sleep quality of rugby union players in the summer season. Thirteen healthy male university rugby union players volunteered for this study. The participants ingested either ice slurry or a room-temperature beverage (control) 30 min before bedtime. A wearable activity-based sleep monitor was used to analyze objective sleep parameters, and the subjective sleep scores were assessed using the Oguri–Shirakawa–Azumi Sleep Inventory, middle-aged and aged version (OSA-MA). No differences in the amount or efficiency of sleep were observed between the ice slurry/control beverage conditions. Significant shortening of the sleep latency was observed in the ice slurry condition as compared with the control beverage condition. Moreover, significant improvement of the subjective sleep score for “feeling refreshed” on the OSA-MA was observed in the ice slurry condition. There were no significant differences in the other subjective sleep scores between the two conditions. The results suggest that ice slurry ingestion before bedtime may improve the latency of sleep onset, accelerate recovery from fatigue, and be useful as a sleep improvement strategy in rugby union players engaging in exercises during the summer season. Full article

The present study uniquely examined the effect of 3 mg·kg⁻¹ chronic caffeine consumption on training adaptations induced by 7-weeks resistance training and assessed the potential for habituation to caffeine’s ergogenicity. Thirty non-specifically resistance-trained university standard male rugby union players (age (years): 20 ± 2; height (cm): 181 ± 7; body mass (kg): 92 ± 17) completed the study), who were moderate habitual caffeine consumers (118 ± 110 mg), completed the study. Using a within-subject double-blind, placebo-controlled experimental design, the acute effects of caffeine intake on upper and lower limb maximal voluntary concentric and eccentric torque were measured using isokinetic dynamometry (IKD) prior to and immediately following a resistance training intervention. Participants were split into strength-matched groups and completed a resistance-training program for seven weeks, consuming either caffeine or a placebo before each session. Irrespective of group, acute caffeine consumption improved peak eccentric torque of the elbow extensors (p < 0.013), peak concentric torque of the elbow flexors (p < 0.005), total eccentric work of the elbow flexors (p < 0.003), total concentric work of the knee extensors (p < 0.001), and total concentric and eccentric work of the knee flexors (p < 0.046) following repeated maximal voluntary contractions. Many of these acute caffeine effects were still prevalent following chronic exposure to caffeine throughout the intervention. The training intervention resulted in significant improvements in upper and lower body one-repetition maximum strength (p < 0.001). For the most part, the effect of the training intervention was equivalent in both the caffeine and placebo groups, despite a small but significant increase (p < 0.037) in the total work performed in the participants that consumed caffeine across the course of the intervention. These results infer that caffeine may be beneficial to evoke acute improvements in muscular strength, with acute effects prevalent following chronic exposure to the experimental dose. However, individuals that consumed caffeine during the intervention did not elicit superior post-intervention training- induced adaptations in muscular strength. Full article

Hepcidin-25 is suggested as a surrogate iron status marker in athletes who show exercise-induced anemia; however, the implications of hepcidin concentration in this population remain poorly understood. This study aimed to investigate the relationship between hepcidin and body fat levels in rugby football players. We included 40 male university rugby football players (RUG) and 40 non-athlete controls. All participants underwent an anthropometric analysis and blood testing that included both hepcidin-25 and ferritin levels. The hepcidin-25 level was slightly (11.6%, p = 0.50) higher, and the ferritin level was significantly (35.9%, p < 0.05) lower, in the RUG group than in controls. The hepcidin-25 to-ferritin ratio was significantly higher (62.5%, p < 0.05) in the RUG group. While significant U-shaped correlations were observed between the body fat and ferritin levels in both groups, the correlations between the hepcidin levels and fat mass index were significantly higher in the RUG group (RUG: r = 0.79, controls: r = 0.45). Notably, the RUG with the lower fat mass index group had a higher hepcidin-25 level, lower ferritin level, and then significantly higher hepcidin-25/ferritin ratio. The hepcidin-25/ferritin ratio may serve as a biomarker for iron status in RUG, especially RUG with lower fat mass. Full article

Gut eubiosis is essential for the host’s health. In athletes, the gut microbiota can be altered by several factors, including diets. While eubiotic gut microbiota in elite rugby players has been reported, our survey found that university rugby players suffered from loose stools and frequent urgency to defecate. To establish the causes of the condition, the microbiota and the concentrations of organic acids in fecal samples of university male rugby players (URP) were analyzed and compared with those of age-matching, non-rugby playing males (control). Body mass indices were significantly (p < 0.05) different between groups. Chao1 index was significant (p < 0.05) lower in URP than in control. The relative abundances of phyla Firmicutes and Bacteroidetes were significantly (p < 0.05) higher and lower, respectively, in URP than in control. Potential pathobiont genera Collinsella, Enterobacter, and Haemophilus were significantly (p < 0.05) abundant, whereas beneficial Akkermansia was lower (p < 0.05) in URP than in control. Succinate, a potential causative of gut inflammation, was five-fold higher in URP than in controls. Our findings all but confirmed that the dysbiotic status of gut in URP. Full article

Using a cross-sectional survey concussion knowledge was evaluated among forty university-level athletes (n = 20, rugby union players; n = 20, Gaelic football players) and eight experienced team coaches (n = 2, rugby union; n = 2, Gaelic football; n = 1, soccer; n = 1, hockey; n = 1, netball; n = 1, basketball). Levels of knowledge of concussion were high across all participants. Coaches had higher knowledge scores for almost all areas; however, there was evidence of important gaps even in this group. Knowledge was not sufficient in identifying concussion, and when it is safe to return to play following a concussion. Impaired knowledge of how to recognise a concussion, and misunderstanding the need for rest and rehabilitation before return to play presents a hazard to health from second impact and more catastrophic brain injury. We discuss reasons for these guideline misconceptions, and suggest that attitude issues on the significance of concussion may underlie a willingness to want to play with a concussion. This suggests the current education on sport-related concussion needs to be expanded for the appropriate management of university-level contact sports. Full article