ECSS Paris 2023: CP-MH03
INTRODUCTION: Shear-wave elastography is an increasingly used method to evaluate muscle stiffness after exercise-induced muscle damage [1]. Research indicates that shear-wave speed variations are not uniform across a muscle group, with notable differences between [2] and even within muscle heads [3]. This study aimed to explore the uniformity of muscle stiffness changes across and within muscle heads following maximal eccentric exercise. METHODS: Fourteen trained male participants (26.6 ± 3.1 years, 81.8 ± 8.2 kg, 180.5 ± 7.3 cm) underwent muscle stiffness evaluation at six distinct sites within the hamstring muscle utilizing shear-wave elastography. Subjects performed 5 x 15 maximal eccentric leg curls at 210°/s on an isokinetic dynamometer and muscle stiffness was assessed before, immediately after training, and on the consecutive four days (24 h – 96 h post). RESULTS: There was no time-by-point interaction for shear-wave elastography (F25, 360 = 0.60, p = 0.93). The main effects of time (F4.01, 288.9 = 2.98, p = 0.02) revealed a significant increase in muscle stiffness from pre (2.04 ± 0.15 m/s) to post (2.11 ± 0.14 m/s) and 24 h post (2.11 ± 0.14 m/s). A significant main effect was also observed for the specific points of measurement (F5, 72 = 4.85, p = 0.0007). CONCLUSION: Maximal eccentric exercise induced an immediate and sustained increase in hamstring muscle stiffness, observable up to 24 hours post-exercise. The findings suggest spatial heterogeneity in stiffness changes across the different hamstring measurement locations, possibly due to non-uniform muscle damage [4] or fiber activation [5]. References: [1] Licen, U; Kozinc, Z. (2022). Using Shear-Wave Elastography to Assess Exercise-Induced Muscle Damage: A Review. Sensors, 22, 7574. https://doi.org/10.3390/s22197574 [2] Kawama, R; Yanase, K; Hojo, T; Wakahara, T. (2022). Acute changes in passive stiffness of the individual hamstring muscles induced by resistance exercise: effects of contraction mode and range of motion. European Journal of Applied Physiology, 122: 2071-2083. https://doi.org/10.1007/s00421-022-04976-6 [3] Kisilewicz A, Madeleine P, Ignasiak Z, Ciszek B, Kawczynski A, Larsen R. (2020) Eccentric Exercise Reduces Upper Trapezius Muscle Stiffness Assessed by Shear Wave Elastography and Myotonometry. Frontiers in Bioengineering and Biotechnology 8: 928. https://doi.org/10.3389/fbioe.2020.00928 [4] Green, M; Sinkus, R; Gandevia, S; Herbert, R; Bilston, L. (2012). Measuring changes in muscle stiffness after eccentric exercise using elastography. NMR Biomed, 25, 852-858. doi: 10.1002/nbm.1801 [5] Kinugasa, R; Kawakami, Y; Fukanaga, T. (2006). Quantiative assessment of skeletal muscle activation using functional MRI. Magn. Reson. Imaging, 24, 639-644. doi: 10.1016/j.mri.2006.01.002
Read CV Carsten SchwieteECSS Paris 2023: CP-MH03
INTRODUCTION: The MOXY is an innovative muscle oxygen monitor that uses near-infrared spectroscopy (NIRS) to measure local oxygen saturation (SmO₂) and total haemoglobin (THb). It continuously measures muscle oxygen saturation by emitting light beams into the muscle. The reflected light is collected by two sensor in near distance [1]. Since hemoglobin and myoglobin change their absorption of infrared light due to oxygenation, NIRS measurements can be used to estimate the oxygen saturation of the muscles (SmO₂). This study investigates the effect of subcutaneous femoral fat (SFF) on the accuracy of SmO₂ measurements, addressing a significant factor that can affect NIRS readings. METHODS: Forty participants (25.4 ± 3.5 years, 68.4 ± 13.1 kg, 173 ± 8.9 cm) had the Moxy device (Idiag AG, Switzerland) placed on the rectus femoris muscle. At 50% of the distance between the spina iliaca anterior inferior and the base oft the patella. Resting SmO2 values were recorded for 5 minutes, and the average of the last 2 minutes was analyzed. SFF thickness was measured using ultrasound (ACUSON Redwood, Siemens, USA). The linear transducer (2.9 – 9.9 MHz) head was placed vertically with as minimal pressure to prevent compression of the underlying tissue. SFF thickness was defined as the distance from the subcutaneous fat tissue-muscle interface to the subcutaneous fat tissue-skin interface. Three images were taken, and the average SFF in centimeters (cm) was used for further calculations. RESULTS: Linear regression analysis showed a moderate positive correlation between SFF in cm and SmO2 values (r = 0.437, p < .001). SFF in cm explained approximately 19.1% of the variation in SmO2 values. The regression coefficients showed that for every cm increase in SFF, SmO2 levels decreased by -1.67 % (intercept = 91.65, p < 0.001; SFF = -1.67, p = 0.005). CONCLUSION: These results show a clear influence of SFF on the SmO2 values, that needs to be taken into account when interpreting SmO2 values. The linear relationship shows that the data of MOXY device are impaired with increasing fat layer, reducing the validity of the information about the muscular SmO₂.Further research is needed to investigate whether the influence of subcutaneous adipose tissue can be mathematically calculated out to improve the accuracy of muscular SmO₂ measurements in people with elevated subcutaneous fat layers. [1] Miranda-Fuentes, C.; Chirosa-Ríos, L.J.; Guisado-Requena, I.M.; Delgado-Floody, P.; Jerez-Mayorga, D. Changes in Muscle Oxygen Saturation Measured Using Wireless Near-Infrared Spectroscopy in Resistance Training: A Systematic Review. Int. J. Environ. Res. Public Health 2021, 18, 4293. https://doi.org/10.3390/ijerph18084293
Read CV Sarah BarawiECSS Paris 2023: CP-MH03
INTRODUCTION: Limited data on the relationship between sports participation and health are available. In particular, few studies have investigated the relationship between contact sports such as rugby, American football, wrestling, boxing, and karate and the prevalence of frequent upper respiratory tract infection (URTI). Therefore, we conducted a cross-sectional study to investigate the relationship between contact sports and the prevalence of frequent URTI among Japanese adults. METHODS: This study was conducted using an Internet survey between July 30, 2021 and August 3, 2021 in Japan. The study participants consisted of 2,500 adults (mean age = 26.1 years, 50% women) Participants were asked about the frequency of URTI before the COVID-19 pandemic, and were asked to select the most appropriate answer among the following options: ‘a few times each year’, ‘about once every year’, ‘once every few years’ and, ‘rarely.’ Participants were also asked if they had ever participated or are currently participating in contact sports: ‘have participated in the past and currently participating [CS]’; ‘have participated in the past, but not currently [Past-CS]’; and ‘have never participated [Neven-CS].’ We combined ‘a few times each year’ and ‘about once each year’ and defined it as frequent URTI (case) and ‘once every few years’ and ‘rarely’ as non-frequent URTI (non-case). Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for the prevalence of frequent URTI were obtained using logistic regression models while adjusting for age, sex, marital status, household income, and education levels. RESULTS: There was a total of 487 (29.3%) frequent URTI cases. Compared to the Never-CS, the ORs (95% CIs) were 1.50 (1.16 − 1.94) for Past-CS, and 2.11 (1.70 − 2.63) for CS, respectively. CONCLUSION: This study showed a higher prevalence of frequent URTI in adults who have participated or are currently participating in contact sports. However, prospective studies are needed to find a causal relationship between contact sports participation and URTI.
Read CV Susumu SawadaECSS Paris 2023: CP-MH03