Effect of COVID-19 lockdown on injury incidence and burden in amateur rugby union

Abstract: Objectives: To analyse match and training injury incidence rates and burden from pre-(2019) and post- COVID-19 (2021) seasons; To analyse injury related variables as mechanisms, type, body locations, severity and the differences of the most common injuries according to playing positions. Design: An observational study was performed according to the consensus statement on injury definitions and data collection from World Rugby. Injury variables were collected retrospectively for 2019 season and prospectively during 2021 season. Setting: Argentinian amateur rugby club. Participants: Male (n ¼ 110) senior amateur rugby players. Main outcome measures: Match and training time loss injuries, time of exposures and injury related variables. Results: Training incidence rate during post-lockdown season (4.2/1000 player-training-hours) was significantly higher (p < 0.001) than the pre-lockdown season (0.9/1000 player match hours). Postlockdown hamstring strain injury (HSI) and concussions match incidence rates were significantly (p < 0.001; p < 0.05 respectively) higher in comparison with 2019 season. Regarding playing positions, backs showed a significantly increase (p < 0.05) in HSI match incidence rate post lockdown. Conclusions: After the COVID-19 lockdown, training incidence rate was significantly higher than previous season (2019), showing the impact of the lockdown restrictions. Coaches and medical staff must consider that players probably need more lead-in time for conditioning and more monitoring after periods of no rugby

Variations in strength-speed-power performance across the season: do true changes occur in elite rugby players?

This study aimed to determine, through the use of a highly sensitive statistical tool, whether real changes in performance were present; and compare the rates of meaningful variations in strength, speed, and power parameters at different time-points during the competitive season in national team rugby players. Thirty-two players were assessed 5 times across the season using the following tests: squat jump and countermovement jump tests; 30-m sprint velocity; and one-repetition maximum (1RM) in the half-squat and bench-press exercises. A repeated-measures analysis of variance was conducted to test for differences between successive time-points. Individual coefficients of variation values were used to set target scores for post-measurements and examine whether changes in performance parameters were greater than the natural test variance, thus providing an indication of whether “true changes” occurred. No significant changes were detected in the vertical jump height, 1RM measures, and sprint velocity and momentum throughout the 11-month period (P > 0.05). True changes occurred much more frequently for strength-power measures than for sprint velocity and momentum. Elite rugby union players did not exhibit significant variations in neuromuscular performance across the competitive period, when a group-based analysis was conducted. However, at the individual level, “true changes” in strength-power- (but not in speed-) related qualities were consistently observed over the competitive season

Examining N-limited soil microbial activity using community-level physiological profiling based on O2 consumption

Nitrogen-limited soil microbial activity has important implications for soil carbon storage and nutrient availability, but previous methods for assessing resource limitation have been restricted, due to enrichment criteria (i.e., long incubation periods, high substrate amendments) and/or logistical constraints (e.g. use of radioisotopes). A microtiter-based assay of basal and substrate induced soil respiration based on O2 consumption may be a rapid, ecologically relevant means of assessing N limitation. The present study evaluated this approach by examining 1) the extent and duration of N limitation on soil respiratory activity following different levels of N fertilization in the field, and 2) the relationship between N-limited activities and growth under the assay conditions. Fertilization rate and the time since fertilization had significant impacts on the degree of N limitation of soil microbial activity. The highest fertilization rate showed the earliest and most persistent reduction in N limitation, as would be predicted from the higher concentration of extractable inorganic soil N observed with this treatment. Bacterial growth under the assay conditions, as estimated by quantitative-PCR of 16S rRNA genes, was less than twofold in soils demonstrating a rapid respiratory response (i.e. peak within 6-8 h of initiating incubation) to up to fourfold in soils demonstrating a slower respiratory response (i.e., peak response after 14 h of incubation). Increased respiratory response with N amendment was usually associated with increased cell growth, although for rapidly responding soils some C sources showed N-limited use without growth. This was likely due to exhaustion of the relatively low levels of available C amendment before growth was detected. The method appears useful for assessing N-limited microbial growth, and it may be effective as a rapid indicator of bioavailable soil N. It may also be a tool to evaluate the complexity of N limitation among various metabolic pathways found in soil microbial communities, particularly if linked to dynamics in community structure and gene activation.Fil: Garland, J. L.. Dynamac Corporation; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Birmele, M.. Dynamac Corporation; Estados UnidosFil: Mackowiak, C. L.. University of Florida; Estados UnidosFil: Lehman, R. M.. North Central Agricultural Research Lab; Estados UnidosFil: Frey, S. D.. University Of New Hampshire; Estados Unido

High-pressure experimental data of CO 2 + mitotane and CO 2 + ethanol + mitotane mixtures

This work presents new experimental phase equilibrium data for mitotane in supercritical CO 2 and mitone in supercritical CO 2 plus ethanol. The synthetic-static method in a high-pressure variable-volume view cell was used to measure the solid-fluid (SF) and the fluid-fluid (FF) equilibrium data. The phase equilibrium experiments were carried out in the temperature range from (298 to 333) K and in the pressure range from (3.44 to 21.84) MPa. The Peng-Robinson equation of state (PR-EoS) was used for describing the fluid phases, and an expression for the fugacity of pure solid mitotane was used for representing the solid phase. This made it possible to model the SF and FF equilibrium data for the CO 2 + mitotane mixtures. Fair agreement was found between experimental and calculated values.Fil: Giufrida, W. M.. Universidade Estadual de Maringá; BrasilFil: Rodriguez Reartes, Sabrina Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Alonso, C. G.. Universidade Estadual de Maringá; BrasilFil: Zabaloy, Marcelo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Cabral, V. F.. Universidade Estadual de Maringá; BrasilFil: Tavares, F. W.. Universidade Federal do Rio de Janeiro; BrasilFil: Cardozo Filho, L.. Universidade Estadual de Maringá; Brasi

Longitudinal changes in anthropometric, physiological, and physical qualities of international women’s rugby league players

This is the first study to assess longitudinal changes in anthropometric, physiological, and physical qualities of international women’s rugby league players. Thirteen forwards and 11 backs were tested three times over a 10-month period. Assessments included: standing height and body mass, body composition measured by dual x-ray absorptiometry (DXA), a blood panel, resting metabolic rate (RMR) assessed by indirect calorimetry, aerobic capacity (i.e.,V˙O2max) evaluated by an incremental treadmill test, and isometric force production measured by a force plate. During the pre-season phase, lean mass increased significantly by ~2% for backs (testing point 1: 47 kg; testing point 2: 48 kg) and forwards (testing point 1: 50 kg; testing point 2: 51 kg) (p = ≤ 0.05). Backs significantly increased their V˙O2max by 22% from testing point 1 (40 ml kg-1 min-1) to testing point 3 (49 ml kg-1 min-1) (p = ≤ 0.04). The V˙O2max of forwards increased by 10% from testing point 1 (41 ml kg-1 min-1) to testing point 3 (45 ml kg-1 min-1), however this change was not significant (p = ≥ 0.05). Body mass (values represent the range of means across the three testing points) (backs: 68 kg; forwards: 77–78 kg), fat mass percentage (backs: 25–26%; forwards: 30–31%), resting metabolic rate (backs: 7 MJ day-1; forwards: 7 MJ day-1), isometric mid-thigh pull (backs: 2106–2180 N; forwards: 2155–2241 N), isometric bench press (backs: 799–822 N; forwards: 999–1024 N), isometric prone row (backs: 625–628 N; forwards: 667–678 N) and bloods (backs: ferritin 21–29 ug/L, haemoglobin 137–140 g/L, iron 17–21 umol/L, transferrin 3 g/L, transferring saturation 23–28%; forwards: ferritin 31–33 ug/L, haemoglobin 141–145 g/L, iron 20–23 umol/L, transferrin 3 g/L, transferrin saturation 26–31%) did not change (p = ≥ 0.05). This study provides novel longitudinal data which can be used to better prepare women rugby league players for the unique demands of their sport, underpinning female athlete health