During the COVID-19 pandemic, entire populations were instructed to live in home-confinement to prevent the expansion of the disease. Spain was one of the countries with the strictest conditions, as outdoor physical activity was banned for nearly two months. This study aimed to analyse the changes in physical activity and sedentary behaviours in Spanish university students before and during the confinement by COVID-19 with special focus on gender. We also analysed enjoyment, the tools used and motivation and impediments for doing physical activity. An online questionnaire, which included the International Physical Activity Questionnaire Short Form and certain “ad hoc” questions, was designed. Students were recruited by distributing an invitation through the administrative channels of 16 universities and a total of 13,754 valid surveys were collected. Overall, university students reduced moderate (−29.5%) and vigorous (−18.3%) physical activity during the confinement and increased sedentary time (+52.7%). However, they spent more time on high intensity interval training (HIIT) (+18.2%) and mind-body activities (e.g., yoga) (+80.0%). Adaptation to the confinement, in terms of physical activity, was handled better by women than by men. These results will help design strategies for each gender to promote physical activity and reduce sedentary behaviour during confinement periods.

Although trunk muscle function has been suggested to be a determinant of judo performance, its contribution to high-level performance in this sport has been poorly studied. Therefore, several tests were used to assess the differences in trunk muscle function between 11 international and 14 national level judo practitioners (judokas). Trunk strength and endurance were assessed using isokinetic tests and core stability was assessed using two protocols: 1) sudden loading, to assess trunk responses to unexpected external perturbations; 2) stable and unstable sitting, to assess the participants’ ability to control trunk balance. No differences between groups were found for trunk flexor isokinetic strength, trunk responses against lateral and posterior loading and trunk control while sitting. However, international level judokas showed significantly higher trunk extensor isokinetic strength (p <0.05) and lower trunk angular displacement after anterior trunk loading (p <0.05) than national level judokas. Few and low (r < 0.512) significant correlations were found between strength, endurance and stability parameters, which suggests that trunk strength and endurance are not limiting factors for trunk stability in competitive judokas. These results support the importance of trunk extensor strength and trunk stability against forward perturbations in elite judo performance.

PurposeThe purpose of this study was to examine the reliability and the learning effect of an isokinetic trunk flexion–extension protocol designed to simultaneously assess trunk muscle strength and endurance. In addition, the effect of the participants' sex on the reliability data was examined.MethodsFifty-seven healthy and physically active young men (n = 28) and women (n = 29) performed the isokinetic protocol 5 times, separated by a week between each of the first 4 sessions and by a month between the last 2 sessions. The protocol consisted of performing 4 trials of 15 maximum flexion–extension concentric exertions at 120°/s (range of trunk motion = 50°). The absolute and relative peak torque and total work were calculated to assess trunk flexion and extension strength. In addition, endurance ratio, modified endurance ratio, fatigue final ratio, recovery ratio, and modified recovery ratio variables were used for the assessment of trunk muscle endurance in both directions.ResultsRegarding the absolute reliability, no relevant changes were found between paired-comparison sessions for most strength and endurance variables, except for total work and relative total work variables in the flexion movement in both sexes. In addition, the typical error of the isokinetic variables was lower than 10% in both males and females, and minimum detectable changes ranged from 7%–20%, with a tendency to be higher in females and in endurance variables. The strength variables showed high intraclass correlation coefficients (ICC; >0.74); however, for the endurance variables only the endurance ratio and the modified endurance ratio obtained moderate to high ICC values (0.57 < ICC < 0.82). In addition, the analysis of the variance reported no significant differences between consecutive pairs of sessions for most variables in both sexes.ConclusionOverall, these findings provide clinicians, trainers, and researchers with a 10-min single-session protocol to perform a reliable muscle strength and endurance evaluation of trunk flexor and extensor muscles, all within the same protocol

Different methods have been developed to quantify trunk muscle strength and endurance. However, some important protocol characteristics are still unclear, hindering the selection of the most suitable tests in each specific situation. The aim of this study was to examine the reliability and the relationship between 3 representative tests of the most common type of protocols used to assess trunk muscle strength and endurance. Twenty-seven healthy men performed each test twice spaced 1 month apart.Trunk strength and endurance were evaluated with an isokinetic dynamometer and 2 field tests including Biering-Sørensen test and Flexion–rotation trunk test. All tests showed a good relative consistency (intraclass correlation coefficient [ICC]> 0.75), except for the isokinetic endurance variables which had low–moderate reliability (0.37 < ICC > 0.65). Absolute reliability seemed slightly better in the isokinetic protocol than in the field tests, which showed about 12% of test–retest score increase. No significant correlations were found between test scores. After a familiarisation period for the field tests, the 3 protocols can be used to obtain reliable measures of trunk muscle strength and endurance. Based on the correlation analysis, these measures are not related, which highlights the importance of selecting the most suitable trunk test for each situation.