For an endurance exercise, we use a spinning class protocol with an average intensity of 63% of the maximum power determined in a graded exercise test until exhaustion. The protocol consisted of a 5 min rest period at the beginning of the measurement as a reference and a 1 h exercise period with 2 × 3 min short drinking breaks. At the beginning and toward the end of the exercise period, the intensity was increased and decreased in steps. Each exercise level was maintained at a constant intensity for 3 min. Fig. 5A shows the intensity profile of the spinning class.
The graded exercise test was performed with each subject at least 2 d apart to the spinning session protocol. The test started with 50 W, and the power was increased by 25 W every 4 min until exhaustion.
All endurance exercises were programmed and run on a cycle ergometer (Ergoline Ergoselect 200, Lode B.V., Netherlands). Four women and four men performed this cycling session during which aerosol particle concentration measurement and respiratory ventilation parameters were assessed.
Both, the graded exercise test and the spinning class session were performed with the aerosol particle measurement system running. By using the same setting, it is possible to check the transferability of the results of the graded exercise test to the practical spinning session.
For this purpose, the respective ventilation and aerosol particle concentration values of the graded exercise test are used according to the power profile of the spinning session, so that a chronological progression can be created.
For the infection risk assessment in a typical gym, also a resistance training study with four women and four men and three different exercises was performed. As in the endurance study, the protocol started with a 5-min resting period as reference. The exercises were leg extensions, biceps curls, and overhead presses. These exercises were selected because they could be performed in the clean air tent, and also the subjects could keep their heads steady and connected to the measurement equipment. For each exercise, three sets with 8 to 10 repetitions were performed. The resistance was adjusted for each exercise and subject to approximately 80% of the 1 RM. Subjects started the sets every 150 s. The individual sets had a duration of approximately 30 s (19 to 42 s). After the third set of each exercise, the break was 4 min long.Fig. 5B shows the exercise protocol.
Due to the short measurement time for these exercise phases (19 to 42 s), the sometimes-low aerosol particle concentration (<80 particles/L), and the counting efficiency of the optical particle counter, it is possible that no particle at all is measured during the exercise phase (19 to 42 s). In these cases, the aerosol particle concentration was set to the resting value.
The graded exercise test was performed with each subject at least 2 d apart to the spinning session protocol. The test started with 50 W, and the power was increased by 25 W every 4 min until exhaustion.
All endurance exercises were programmed and run on a cycle ergometer (Ergoline Ergoselect 200, Lode B.V., Netherlands). Four women and four men performed this cycling session during which aerosol particle concentration measurement and respiratory ventilation parameters were assessed.
Both, the graded exercise test and the spinning class session were performed with the aerosol particle measurement system running. By using the same setting, it is possible to check the transferability of the results of the graded exercise test to the practical spinning session.
For this purpose, the respective ventilation and aerosol particle concentration values of the graded exercise test are used according to the power profile of the spinning session, so that a chronological progression can be created.
For the infection risk assessment in a typical gym, also a resistance training study with four women and four men and three different exercises was performed. As in the endurance study, the protocol started with a 5-min resting period as reference. The exercises were leg extensions, biceps curls, and overhead presses. These exercises were selected because they could be performed in the clean air tent, and also the subjects could keep their heads steady and connected to the measurement equipment. For each exercise, three sets with 8 to 10 repetitions were performed. The resistance was adjusted for each exercise and subject to approximately 80% of the 1 RM. Subjects started the sets every 150 s. The individual sets had a duration of approximately 30 s (19 to 42 s). After the third set of each exercise, the break was 4 min long.
Due to the short measurement time for these exercise phases (19 to 42 s), the sometimes-low aerosol particle concentration (<80 particles/L), and the counting efficiency of the optical particle counter, it is possible that no particle at all is measured during the exercise phase (19 to 42 s). In these cases, the aerosol particle concentration was set to the resting value.
