Our study has found a 64% reduction on CrossFit training during quarantine and a 18% reduction of UI during this period. The sudden onset of a state of social isolation implies a radical change in the population's lifestyle, such as the level of physical activity, eating habits and sleep . Thus, many medical societies released information on how to avoid a sedentary lifestyle during COVID-19 pandemic [14,15]. At the same time, gyms and elite athletes provided free online training to help people stay active at home . One of the main characteristics of CrossFit training is that it is
performed in a gym equipped with rings, bars, and weights . Therefore, one of the possibilities of this study was that CrossFit practitioners would not be able to train at home. However, it was observed that 98.5% of the interviewees maintained their training, adapting their exercise routine indoors.
Exercises that needed special equipment like wall ball and medicine ball were the least practiced by the participants (10.9% and 15.5% respectively), while exercises using participant’s own body weight, such as air squat and push up, were maintained by most athletes (98.4% and 98.2%, respectively). Another interesting fact is that the specificity of CrossFit training involves the association of Olympic lifting exercises (squats, sprints, throws); aerobic exercises (such as rowing, running and cycling) and gymnastic movements (such as handstands, parallel bars, rings and bars) . In this sense, it was a surprise to realize in our study that the interviewees were able to maintain their physical exercise routine in their homes, even in small environments such as a balcony.
Studies show that about 5% of CrossFit practitioners have some degree of addiction to exercise . If this motivation may have been the explanation for maintaining their routine at home, on the other hand, it concerns the effect of high intensity exercise on the immune system. It is observed that 22 athletes reported having symptoms of COVID-19 and, as a treatment, they did social isolation. It has been shown that high-intensity training can lead to lymphocyte apoptosis and predispose to immunosuppression . Even in recreational athletes, a CrossFit® training protocol with 10 repetitions of horizontal bench press, deadlifts, and squats, performed at 75% of a maximum repetition, and without a break, significantly
increases interleukin-6 (IL6). In terms of COVID-19, data suggest that IL-6 may play a key role in the evolution of the inflammatory immune response that causes acute respiratory distress syndrome.
The reduction of UI during exercise after starting the quarantine was statistically significant and the reasons appointed by the respondents were the interruption of double under exercises and the reduction in the intensity of the training. Double under is the CrossFit movement that most frequently increases the intra-abdominal pressure (429 cm H2O), this value being one of the highest ever attributed to any sporting gesture . In a previous study performed from our group , it was the exercise mostly associated with UI. Thus, the interruption of this exercise in the quarantine explains the improvement in urinary incontinence. Another important fact is that the increase in intra-abdominal pressure in CrossFit exercise varies with the intensity of the training, repetitions, and the use or not of load . In this sense, quarantine may have indirectly assured the protective effect to the pelvic floor, due to the difficulty in using training accessories and decreased training intensity.
The volume of training has been reported in previous studies as a risk factor for athletic incontinence. Women who play high-impact sports or who have a higher volume of training should be aware of the symptoms associated with pelvic floor dysfunction [9, 10]. The level of exercise can be calculated based on the time (in minutes) usually spent per week or the intensity (light, moderate, intense). Normally, athletes, from any modality and who train for competitive purposes are at twice the risk for UI when compared to sedentary ones.
Some reports indicate that physical inactivity will persist long after we recover from the COVID-19 pandemic . In this sense, maintaining the CrossFit training routine at home was a positive element for future health .
To our knowledge, this is the first study analysing the impact of COVID-19 quarantine to CrossFit training and the repercussion on UI during exercise. The limitations of this study include the use of an online questionnaire, the lack of physical examination, the self-report of COVID-19 symptoms without laboratorial confirmation. Despite sample size calculation has been performed, there is a risk of type 2 error regarding to the associated factors for the reduction of CrossFit training, and for this reason we opted out to not performing a multivariate analysis.
In conclusion, quarantine by COVID-19 improved athletic incontinence in CrossFit practitioners due to decreased training intensity and interruption of higher intraabdominal pressure exercises.