Recent studies have shown that polarized training (i.e. the combination in the same session of intermittent high intensity exercise training, consisting of repeated, short-duration, high-intensity exercises on a cycle ergometer or a treadmill, and moderate exercise) can encourage the participation of obese people in body weight reduction programs, providing more dynamic exercises, less tiring and therefore more acceptable.

To date, no data are available on the effects of polarized exercise in the rehabilitation of obese adolescents, who are often unwilling to engage in prolonged and monotonous motor activities.

The demonstration that the polarized exercise might encourage the participation of obese adolescents in multidisciplinary body weight reduction programs, improve the cardiovascular capacity and also favor an adequate oxidation of lipids during the phase of exercise and post-exercise rest, could support its prescription in the programs of integrated metabolic rehabilitation of adolescent obesity.

Subjects 24 obese adolescents (BMI-standard deviation score > 2), male, age range: 13-18 years, admitted to the Division of Auxology, San Giuseppe Hospital, Istituto Auxologico Italiano, Piancavallo (VB) for a 3-week metabolic rehabilitation program.

Measures:

In basal conditions (hospital admission) and at the end of the metabolic rehabilitation period (21st day), the anthropometric characteristics and body composition will be evaluated by means of tetrapolar impedancemetry (Human-IM Scan, DS-Medigroup, Milan, Italy). In basal conditions all the recruited subjects will undergo an incremental test on a treadmill aimed at determining the maximum lipid oxidation, the peak oxygen consumption value (peak V'O2), and the intensities corresponding to the various percentages of the V' Peak O2 (Medical graphics Corporation, St Paul, MN, USA). Subsequently, subjects will be randomly divided into two groups. The first group (no. 12) will perform a Polarized workout lasting approximately 40 minutes (two sessions/day, 1 in the morning and 1 in the afternoon, 5 days a week), characterized by a 5-minute warm-up performed at 50% of the V 'peak O2, followed by 3 sets of 2 minutes at 95% of peak V'O2, interspersed with 1 minute of recovery at 40% of peak V'O2, followed by 30 minutes of moderate activity at 60% of V'O2 'O2 peak. The second group (no. 12) will perform two sessions (one in the morning and one in the afternoon, 5 days a week) of a high intensity workout (HIIT) characterized by a 10-minute warm-up performed at 50% of peak V'O2 , followed by 6 series of 40 s of high-intensity walking corresponding to 95% of peak V'O2, interspersed with 5 minutes of walking at 40% of peak V'O2, ending with 5' of cool-down at 50% of the peak V'O2. Both workouts (24 sessions in total, spread over 12 days) will be matched for the same calories expended. At the end of the rehabilitation period, all subjects will again be subjected to an incremental test on a conveyor belt with the same execution methods as for the baseline test.

Inclusion Criteria:

i. obesity (BMI-standard deviation score > 2) ii. sex: male iii. age range: 13-18 years iv. hospitalization for integrated metabolic rehabilitation program

Exclusion Criteria:

None