Mouthguards (MGs) are highly recommended in rugby. Airway obstruction and a resulting decrease in power output are potential disadvantages of their usage. The aim of the study was to assess possible limitations of “vented” (MGV) and custom-made mouthguards (MGC) on rugby players’ performance. The MG effects were investigated in 13 male first-league rugby players ranging from 18–34 years old. First a lung function test was completed. Then a double incremental treadmill test was performed to measure maximum aerobic performance, ventilation, VO2, VCO2, heart rate, and lactate. Effects on sprint times (10 and 40 m) and countermovement jumps were also investigated. Peak flow values were significantly decreased with MGV by about 0.9 l/s. Neither ventilatory parameters nor oxygen uptake were affected by either of the mouthguards. Maximum lactate was significantly decreased in both MG types vs. no MG use. The maximum running velocity was similar in all tests. The aerobic energy turnover was moderately increased with the MGC and MGV. No effects were seen on sprint times or jump tests. Although neither type of mouthguard had a significant impact on maximum performance in treadmill running, the anaerobic energy turnover was decreased.

The importance of using mouthguards as well as their low acceptance rate have been demonstrated. The aim of this study was to investigate the influence of customized mouthguards on hemodynamics.. This randomized crossover study used data from 13 subjects (23.5±1.4 years). The cardiopulmonary and metabolic parameters were observed during ergometer tests without mouthguard (control) in comparison to two types of mouthguards (with and normal without breathing channels). Maximum ventilation was significantly decreased with the normal mouthguard (113.3±30.00 l ∙ min−1) in contrast to the mouthguard with breathing channels (122.5±22.9 l ∙ min−1) and control (121.9±30.8 l ∙ min−1). Also the inspiration time was longer when using the normal mouthguard (0.70±0.11 s) compared to the mouthguard with breathing channels (0.63±0.11 s) and control (Co 0.64±0.10 s). Lactate was also increased under the influence of the mouthguard with breathing channels (10.72±1.4 mmol ∙ l−1) compared to the control (9.40±1.77 mmol ∙ l−1) and the normal mouthguard (9.02±1.67 mmol ∙ l−1). In addition, stroke volume kinetics (p=0.048) and maximum heart rates (p=0.01) show changes. Despite equal levels of oxygen uptake and performances under all three conditions, the use of mouthguards showed differences in cardiopulmonary parameters. The use of mouthguards during exercise does not affect physical performance and can be recommended for injury prevention.

Schulze, A, Laessing, J, Kwast, S, and Busse, M. Influence of a vented mouthguard on physiological responses in handball. J Strength Cond Res XX(X): 000-000, 2018-Mouthguards (MGs) improve sports safety. However, airway obstruction and a resulting decrease in performance are theoretical disadvantages regarding their use. The study aim was to assess possible limitations of a "vented" MG on aerobic performance in handball. The physiological effects were investigated in 14 male professional players in a newly developed handball-specific course. The measured values were oxygen uptake, ventilation, heart rate, and lactate. Similar oxygen uptake (V[Combining Dot Above]O2) values were observed with and without MG use (51.9 ± 6.4 L·min·kg vs. 52.1 ± 10.9 L·min·kg). During maximum load, ventilation was markedly lower with the vented MG (153.1 ± 25 L·min vs. 166.3 ± 20.8 L·min). The endexpiratory concentrations of O2 (17.2 ± 0.5% vs. 17.6 ± 0.8%) and CO2 (4.0 ± 0.5% vs. 3.7 ± 0.6%) were significantly lower and higher, respectively, when using the MG. The inspiration and expiration times with and without the MG were 0.6 ± 0.1 seconds vs. 0.6 ± 0.1 seconds and 0.7 ± 0.2 seconds vs. 0.6 ± 0.2 seconds (all not significant), respectively, indicating that there was no relevant airflow restriction. The maximum load was not significantly affected by the MG. The lower ventilation for given V[Combining Dot Above]O2 values associated with MG use may be an effect of improved biomechanics and lower respiratory drive of the peripheral musculature.

Background: Novel intraoperative imaging techniques, namely, hyperspectral (HSI) and fluorescence imaging (FI), are promising with respect to reducing severe postoperative complications, thus increasing patient safety. Both tools have already been used to evaluate perfusion of the gastric conduit after esophagectomy and before anastomosis. To our knowledge, this is the first study evaluating both modalities simultaneously during esophagectomy. Methods: In our pilot study, 13 patients, who underwent Ivor Lewis esophagectomy and gastric conduit reconstruction, were analyzed prospectively. HSI and FI were recorded before establishing the anastomosis in order to determine its optimum position. Results: No anastomotic leak occurred during this pilot study. In five patients, the imaging methods resulted in a more peripheral adaptation of the anastomosis. There were no significant differences between the two imaging tools, and no adverse events due to the imaging methods or indocyanine green (ICG) injection occurred. Conclusions: Simultaneous intraoperative application of both modalities was feasible and not time consuming. They are complementary with regard to the ideal anastomotic position and may contribute to better surgical outcomes. The impact of their simultaneous application will be proven in consecutive prospective trials with a large patient cohort.

Background Some studies have suggested that a mouthguard is a performance-enhancing device due to a remote voluntary contraction. The extent to which a mouthguard can induce this phenomenon, e.g., by potentially increasing biting, has not been clarified. This study’s aim was to investigate the muscular activity of the maxillary and peripheral musculature and motor performance during a rest and exercise test. Methods Our study comprised 12 active, male, professional young handball players (age 18.83 ± 0.39 years). Their performance, electromyographic (EMG) muscle activity (Σ), and lateral deviation (Δ) of the masticatory and peripheral musculature were measured during rest in a maximum bite force measurement, one-legged stand, a kettlebell swing exercise and a jump test while wearing a customized mouthguard (CMG) or not wearing one (Co). Results Maximum bite force measurements did not differ significantly in their mean values of muscle activity (Σ) for the masseter and temporalis muscles (Co 647.6 ± 212.8 µV vs. CMG 724.3 ± 257.1 µV p = 0.08) (Co 457.2 ± 135.5 µV vs. CMG 426.6 ± 169.3 µV p = 0.38) with versus without CMG. We found no differences in the mean activation values during a one-legged stand, the kettlebell swing, and jump test (Σ) in any of the muscles tested. Lateral deviations (Δ) wearing a CMG were significantly less in the erector spinae during the kettlebell swing (Co 5.33 ± 3.4 µV vs. CMG 2.53 ± 1.8 µV p = 0.01) and countermovement jump (Co 37.90 ± 30.6 µV vs. CMG 17.83 ± 22.3 µV p = 0.03) compared to the performance without a CMG. Jump height, rotation moment, and balance were unchanged with versus without CMG. Conclusion Our results at rest and during specific motor stress show no differences with or without a CMG. The improved peripheral muscular balance while wearing a CMG indicates improved muscular stabilization.

Background The SARS-CoV-2 virus and its long-term consequences in adolescents have a global impact on upcoming medical issues. The aim of this study was to investigate the effects of a SARS-CoV-2 infection on cardiorespiratory parameters in young athletes. Methods In a cohort study involving repeated measurements during a six-month period, cardiorespiratory parameters were assessed in infected (SCoV) and non-infected (noSCoV) athletes. We evaluated handball players (17.2 ± 1.0 years) via performance diagnostics and a specific examination after a SARS-CoV-2 infection or without. Results We observed no significant differences between the two groups at the first visit. But between the first and second visit, the SCoV group’s maximum power output was significantly lower than the noSCoV group’s (− 48.3 ± 12.5; p ≤ 0.01 vs. − 15.0 ± 26.0 W; p = 0.09). At the second visit, lung diffusion capacity (DLCO/VA, %predicted) did not differ between groups (111.6 ± 11.5 vs. 116.1 ± 11.8%; p = 0.45). HR during comparative stress showed no group differences. The SCoV group’s mean oxygen uptake during incremental exercise was lower (Two-way-ANOVA: 1912 vs. 2106 ml; p ≤ 0.01; mean difference: − 194 ml; 95% CI − 317 to − 71); we also noted a significantly lower stroke volume course during exercise (Two-way-ANAOVA: 147.5 vs. 169.5 ml; mean difference: − 22 ml; p ≤ 0.01; 95% CI − 34.2 to − 9.9). The probability of premature ventricular complexes after a SARS-CoV-2 infection yielded an odds ratio of 1.6 (95% CI 0.24–10.81). Conclusions The physical performance of young athletes infected with SARS-CoV-2 was impaired. This decreased performance is probably due to cardiac and/or peripheral deconditioning. Studies with larger cohorts are needed to make more profound conclusions.

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Caliper and ultrasound (US) are used to measure subcutaneous fat tissue depth (SFT) and then to calculate total body fat. There is no evidence-based recommendation as to whether caliper or US are equally accurate. The aim of this paper was therefore to compare reliability of both methods. In this methodical study, 54 participants (BMI: 24.8 ± 3.5 kg/m2; Age: 43.2 ± 21.7 years) were included. Using systematic body mapping, the SFT of 56 areas was measured. We also analyzed 4 body sites via MRI. A comparison between caliper and US detected clear differences in mean SFT of all areas (0.83 ± 0.33 cm vs. 1.14 ± 0.54 cm; p < 0.001) showing moderate reliability (ICC 0.669, 95%CI: 0.625–0.712). US and MRI revealed in the abdominal area a SFT twice as thick as caliper (2.43 ± 1.36 cm vs. 2.26 ± 1.32 cm vs. 1.15 ± 0.66 cm; respectively). Caliper and US revealed excellent intrarater (ICC caliper: 0.944, 95%CI: 0.926–0.963; US: 0.934, 95%CI: 0.924–0.944) and good interrater reliability (ICC caliper: 0.794, 95%CI: 0.754–0.835; US: 0.825, 95%CI: 0.794–0.857). Despite the high reliability in measuring SFT that caliper and US show, our comparison of the two methods yielded clear differences in SFT, particularly in the abdominal area. In accuracy terms, US is preferable for most mapping areas.