The subjects were fitted with a chest HR transmitter and wrist monitor recorder. HR was recorded, from the beginning of the session, using individual Polar RS400 (Polar? Vantage thenthereby NV, Polar Electro Oy, Finland), and subsequently exported and analyzed using the Polar Pro-Trainer? software program (Polar Electro Oy, Finland). The subjects could not see their HR measurements during the experimental trial, because it could influence their perceived effort on the Borg and OMNI RPE scales. For this reason, a sticker was placed on each HR monitor. The experimental trial was divided into four stages: a warm-up (10 minutes in a seated position, with a cadence of 90�C100 RPM (revolutions per minute)), a main phase (35 minutes, where the subjects alternated between normal seated positions and seated and standing climb cycling, between 60�C80 RPM in climb techniques and between 80 �C 110 RPM in normal seated cycling).

Then, a cool down (5 minutes, with a cadence of 80�C100 RPM) in a seated position and, finally, stretching exercises, of the principal muscles used in the session off cycling. During the experimental trial, HR was recorded every 5 s. The participants were instructed to follow the directions of a qualified indoor cycling instructor, which included recommended frequencies of pedalling (RPM) in each phase of the session and recommended cycle resistance. The instructor provided feedback to help the subjects to regulate their intensity. Although the resistance of the cycle could be freely changed by the participants during the session, the study subjects had to follow the instructions about the resistance and the RPM indicated by the instructor.

The Borg 6�C20 RPE and the OMNI 0�C10 scales were used to assess perceived exertion. The RPE is a 15-point single-item scale ranging from 6 to 20, with anchors ranging from 6 ��No exertion�� to 20 ��Maximum exertion��. The OMNI 0�C10 scale has a category rating format that contains both pictorial and verbal descriptors positioned along a comparatively narrow numerical response range, 0�C10. Each pictorial descriptor is consistent with its corresponding verbal descriptor, from 0 ��Extremely easy�� to 10 ��Extremely hard��. Both RPE scales were positioned within sight in the indoor cycling room. The subjects were instructed to give an overall perception about how hard the exercise felt according to both RPE scales every five minutes, from the start to the end of the indoor cycling session.

These values were written on a record sheet which the subjects had on their handlebars. Before the measurements, subjects were asked to read instructions on how to use these scales. A familiarization period of two weeks (and a minimum of 3 sessions per week) prior Carfilzomib to the experimental trial was carried out to accustom the participants with the Borg and the OMNI RPE scales. The first session consisted of familiarization to the RPE scales.