the importance of intensity in the prescription of health training. [la importancia de la intensidad en la prescripción de entrenamiento para la salud].

Traditionally the prescription of physical activity for health has been focused on continuous low-intensity activities. These trainings were oriented to the development or maintenance of cardiorespiratory fitness, prescribing intensities close to 50% of maximal oxygen uptake (VO2max) (ACSM, 1978). These intensity prescriptions have been criticized for their lack of specificity to obtain adaptations and for the often erroneous intensity prescribed, considering using the heart rate reserve (HRR) or reserve oxygen uptake (VO2R) as parameters to prescribe exercise intensity (ACSM, 1998; Karvonen, Kentala and Mustala, 1957). In the same way, others authors proposed the necessity to overcome the mobilization threshold to obtain adaptations, then, the prescribed intensity should be higher, proposing intensities that can reach the 85% of VO2R (ACSM, 2006; Asikainen, et al., 2002; Mors et al., 2004). Although these new intensity requirements, the exercises recommended still based on continuous methodologies, using aerobic exercises like walking, running... Currently, new training methodologies based on high intensity interval and strength exercises are showing major adaptations to different organic systems and greater efficiency than traditional training models based on continuous and low intensity training.