The indoor cycling trainer orders an intensity to reach in each music track and ref 3 the participants have to adjust the tension on the flywheel. Indoor cycling classes are usually very demanding because this activity is viewed as an exercise where a large number of calories is burned. Therefore, a lot of sedentary people participate in this activity in order to lose weight; it is a motivating activity for them. In this sense, Valle et al. (2009; 2010) reported that indoor cycling associated with a restricted diet is an excellent option in controlling obesity and serum lipids. Bianco et al. (2010) found a decrease in body weight, without any restriction on food consumption, and an improvement in cardiorespiratory fitness in young overweight women.

However, these authors fundamentally recommend training protocols which are intense and length specific to the fitness level of the participants. Several studies have reported that indoor cycling is a strenuous physical activity (Battista et al., 2008; Caria et al., 2007; Foster et al., 2006; L��pez-Minarro and Muyor, 2010; Muyor and L��pez-Mi?arrro, 2012; Richey et al., 1999) which may be inappropriate for novice subjects (Battista et al., 2008; Caria et al., 2007; Foster et al., 2006). Moreover, in literature there are some rhabdomyolysis cases due to the practice of indoor cycling (Montero et al., 2009; Young and Thompson, 2004). Battista et al. (2008) found in two simulated indoor cycling classes that there are some moments of the session when the VO2 exceeded the VO2max observed during incremental testing. Crumpton et al.

(1999) found that the HR response was 83% of the subjects�� age-predicted maximum in 40 minutes of indoor cycling. Kang et al. (2005) found that a Spinning? (indoor cycling) session resulted in a greater VO2 in comparison to a constant intensity protocol in cycling. L��pez-Mi?arro and Muyor (2010) found mean values of the % heart rate reserve (%HRR) around 72% in the cardiovascular phase in novice subjects. Recently, Muyor and L��pez-Mi?arro (2012) found a %HRR of around 80% in subjects who had 6 months experience in the indoor cycling. Most fitness centers do not have a physiological department and biomedical instruments such as an electrocardiogram or VO2 equipment to evaluate the physiological responses in their users because it is quite expensive and requires qualified staff.

For these reasons, it is common to use a heart rate monitor or rating of perceived exertion (RPE) scales. The RPE is a recognized marker of intensity and of homeostatic disturbance during exercise (Eston, 2012). In fact, previous studies have shown strong relationships between RPE and physiological parameters such as blood lactate Entinostat response (Irving et al., 2006) and VO2 (Eston et al., 2006; Eston et al., 2005). Other studies have evaluated the validity and reliability of RPE for elite swimmers (Psycharakis, 2011), Australian footballers (Scott et al.