Controlled Evaluation of an Exercise Program for Overweight Adolescents

Physical activity decreases as young people get older, especially during the shift from early to late adolescence. Unfortunately, around 81% of school-aged children worldwide between the ages of 11 and 17 do not meet the recommendation of at least one hour of physical activity per day - and this is also true in Switzerland. Not being active enough, whether normal weight or overweight, can lead to long-term health problems and is a major factor in becoming overweight over time. This results in healthcare costs and negatively affects quality of life. Supporting physical activity in overweight youth requires well-rounded, thoughtful programs.

The investigators studying the impact of the movement programs now! and now!+ on the physical activity and health of young people. The goal is to look at both physical and mental changes equally.

Taking part in this study involves minimal physical or mental risk for the participants. These small risks from the testing methods and activities are taken into account in how the program is explained and carried out.

The benefits for the participants - feeling healthier and fitter physically, and more confident and capable mentally - clearly outweigh any potential risks, thanks to the additional, guided, and personalized exercise program.

The participants take part in the now! and now!+ exercise programs run by the Basel-Stadt Sports Office and the DSBG. now! is a 90-minute group session with up to 14 young people, while now!+ is a 90-minute small-group session with 2 to 4 participants. Both programs take place once a week over a 12-month period and pause during school holidays (38 training weeks in total).

Each session includes a warm-up, a strength or endurance training block, and a coordination phase. The program is modular and adapted to the physical and personal needs of each participant. This ensures that overweight adolescents are not overstrained and don't develop symptoms like pain, frustration, or lack of motivation (Behringer et al., 2011), while still allowing for a training stimulus that supports physical improvement.

The results of the evaluations are directly used to improve and further develop the exercise program. The overall project includes three rounds, each consisting of one year of training and three test sessions, each lasting about two hours. The now! and now!+ programs are held weekly for a total of 38 weeks per year, with breaks during school holidays.

Each of the three test sessions includes the same set of assessments (see "Study Intervention") and follows a set order: The process begins with measuring body size and blood pressure, followed by a static retinal vessel analysis. After these medical checks, participants do a 5-minute warm-up on a stationary bike at a set resistance level. Then, strength tests are performed: knee extension on the IsoMed 2000, handgrip strength, and jump power on the Leonardo force plate. The endurance test using spiroergometry marks the end of the physical assessments.

Finally, impulse control is tested, and participants complete a set of questionnaires. At the end of the session, each participant is given an actigraph (a small motion sensor worn on the body) to track their physical activity over the following seven days.


Eligibility Criteria:
Inclusion Criteria:

* BMI above the 90th percentile for their age and gender (WHO reference table)
* Deficits in movement motivation and motor skills
* No health complaints or movement-restricting conditions
* No health risks for maximal exertion
* Ability to verbally communicate pain or discomfort
* Unremarkable PAR-Q questionnaire
* Signed parental consent form

Exclusion Criteria:

* Acute or chronic illness
* Inability to follow the study procedures (e.g., language barriers, psychological disorders)