Evidence of exercise-induced muscle damage following a simulated rugby league match

Abstract

This study investigated symptoms of exercise-induced muscle damage following a simulated rugby league game. Ten male participants were assessed before, immediately after (0 h), and 24 and 48 h after the simulated game. Perceived muscle soreness was higher at all time points (P=0.001) and creatine kinase values were increased at 24 h following the simulated game (P=0.001). Peak knee extensor torque at 60 deg · s^?1 was reduced up to 48 h (P =0.04) but was unchanged at 240 deg · s^?1. Similarly, peak knee flexor torque at 60 deg · s^?1 was lower than baseline up to 24 h, while at 240 deg · s^?1 it was reduced at 24 h only (P=0.045). Correlations between changes in strength loss of the knee extensors and fat mass to fat-free mass ratio reveleaved no significant relationship between variables (P >0.05). In addition, countermovement jump performance was reduced at 0 and 24 h following the simulated game (P=0.008). Our results suggest that symptoms of exercise-induced muscle damage occur up to 48 h following a simulated rugby league match. Coaches should be cognisant of the large increases in muscle soreness and reductions in slow velocity force generation, and should adapt training accordingly in the 48 h period following a game.     

Effects of interrupting prolonged sitting on postprandial glycemia and insulin responses: A network meta-analysis

PurposeThis study aimed to evaluate the effectiveness of physical activity (PA) interrupting prolonged sitting (PS) on postprandial glycemia and insulin responses among adults.MethodsPubMed, EMBASE, Cochrane Library, Web of Science, CINAHL, PsycINFO, and the China National Knowledge Infrastructure databases were searched through September 30, 2020. Randomized controlled trials (RCTs) that examined the effect of all forms of PA interrupting PS on postprandial glycemia and/or insulin responses among adults without chronic diseases were included in this study. The risk of bias of included studies was evaluated based on the Cochrane tool. A network meta-analysis was performed to estimate the summary standardized mean differences (SMDs) with 95% confidence intervals (95%CIs) with random effects.ResultsThirty crossover RCTs were included in our review. These RCTs included 9 types of interventions that interrupted PS. When compared to PS by itself, light-intensity PA intermittent interrupting (LPA-INT) PS and moderate-intensity PA intermittent interrupting (MPA-INT) PS significantly lowered postprandial glycemia (SMD = –0.46, 95%CI: –0.70 to –0.21; SMD = –0.69, 95%CI: –1.00 to –0.37, respectively) and significantly reduced postprandial insulin response (SMD = –0.46, 95%CI: –0.66 to –0.26; SMD = –0.47, 95%CI: –0.77 to –0.17, respectively). Results of the clustered ranking plot indicated that MPA-INT was the most effective intervention in lowering postprandial glycemia and insulin responses.ConclusionReplacing PS with MPA-INT or LPA-INT has a positive effect in reducing postprandial glycemia and insulin responses, with MPA-INT being the optimal intervention strategy.     

A study of prolonged jaundice screen in healthy term babies

Prolonged jaundice in most of the term babies is associated with breast milk but in some cases it can be a marker for a range of hepatobiliary, hematological, metabolic, endocrine, infectious and genetic disorders that are associated with significant mortality and morbidity if not diagnosed in time. A diagnosis of conjugated hyperbilirubinaemia warrants urgent investigation. Protocols for investigating prolonged jaundice screen vary in complexity and the yield from screen has not been assessed. In order to address these issues, we carried out a study on healthy term babies referred to our day unit with prolonged jaundice. Infants were examined by pediatrician and investigations done as per unit protocol. Prolonged jaundice screen was found to be helpful in excluding biliary atresia and to support the diagnosis of breast milk jaundice. Present study concluded that negative prolonged jaundice screen is reassuring in healthy term babies and further investigations are unwarranted unless otherwise specified.     

An Analysis of the Creative Ways of Writing in Melanctha

Melanctha is the longest part of the Three Lives stories of Gertrude Stein in which the author tried many creative ways of writing. The most outstanding two writing methods used by Gertrude Stein are variations of repetition and the prolonged present tense. This essay will try to analyze how the author demonstrates her aesthetic, philosophical and ethical thoughts by a new writing style beneath the surface of her work.     

Ad libitum fluid intakes and thermoregulatory responses of female distance runners in three environments

Ad libitum fluid intakes and thermoregulatory responses were compared in eight female marathon runners during a 30 km treadmill run at individual best marathon race pace (range = 2.45-4.07 m·s -1 ) under three wet bulb globe temperature conditions (25°C, 17°C and 12°C, corresponding to hot, moderate and cool conditions, respectively). Rectal temperature, mean skin temperature and heart rate were recorded at 10 min intervals and expired air was collected every 5 km during exercise. Simulated water stations were also provided at 5 km intervals with voluntary fluid intake being recorded. Blood was drawn before and after exercise for the determination of plasma volume changes and osmolarity. Ad libitum fluid intakes in the hot trial (0.70 - 0.31 l·h -1 ; mean - s) were greater (P? 0.05) than in the cool (0.47 - 0.13 l·h -1 ) but not the moderate (0.54 - 0.26 l·h -1 ) trial. Each volume replaced 63%, 68% and 73% of total sweat losses in each condition, respectively, and kept dehydration below ~3% of body mass. After the initial 30 min of exercise, rectal temperature was maintained well below 39°C for >2 h of continuous running. The results demonstrate that the thermoregulatory responses of female distance runners to exercise in variable, but compensable, weather conditions is well maintained when ad libitum fluid intakes replace approximately 60-70% of sweat losses.