Controlled Evaluation of an Exercise Program for Overweight Adolescents (Now!)

Now! Project - a Controlled Evaluation of a Physical Activity Program for Adolescents With Overweight

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Adolescent; Quality of Life; Pediatric Obesity; Health Promotion; Impulse Control Disorders; Exercise Therapy; Program Evaluation; Aerobic Capacity; Strength Training Effects; Retinal Vessels
• Intervention / Treatment: Behavioral: training group

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Lukas Nebiker, M.sc.; Phone Number: +41 (0)61 207 47 52; Email: lukas.nebiker@unibas.ch
• Study Contact Backup: Name: Christoph Hauser, Phd; Phone Number: +41 (0)61 207 47 47; Email: christoph.hauser@unibas.ch

Study Locations

• Switzerland
  • Basel, Switzerland, 4052
    • Department of Sport, Exercise and Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

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)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: training group; training group: Two peer-group sessions per week, each including at least 90 minutes of training/workout involving moderate to vigorous physical activity.	Behavioral: training group; Participants in training group are invited to take part in two structured training sessions per week, each lasting 90 minutes: One session takes place in a larger group setting, where participants engage in physical activities and games together. The second session is held in a small group format with 1-2 peers-either friends the participant already knows or peers they meet during the larger group session. Each training session is supervised by a qualified instructor and includes: Fun, game-based activities Short workouts aimed at improving fitness A focus on social interaction, enjoyment, and participation The sessions are designed to be supportive, engaging, and motivating, with the goal of increasing physical activity in a positive group environment.
No Intervention: control group; There is no intervention in the control group. The control group only receives the WHO physical activity recommendations as well as the results of the assessments in the form of a detailed health report. Control arm: Observation of physical and psychological development without additional intervention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Aerobic performance	Cardiopulmonary exercise testing (CPET) will be performed on a mechanically braked bicycle ergometer (Ergoselect 200, Ergoline GmbH, Germany). Ventilation and gas exchange will be measured breath-by-breath using a face mask connected to a Cortex Metalyzer 3B (Cortex Biophysik GmbH, Germany). Basic spirometry is conducted before testing. A 12-lead ECG (Customed GmbH, Germany) is used at rest and during exercise to monitor heart rate and detect abnormalities. CPET begins with a 3-minute resting phase and continues using one of five established protocols (Wagner et al., 2019). Participants are verbally encouraged throughout. Gas exchange values are averaged every 30 seconds. VO₂max and RERmax are recorded as peak values at or before exhaustion. Subjective exertion is assessed every 2 minutes and post-exercise using the Borg scale (Borg, 1998).	over the time period of one year of intervention, october to october
Strength assessment	The measurement of isometric maximal voluntary contraction of lower extremity muscles will be performed in a seated position in a dynamometer (Isomed 2000, D. & R. Ferstl GmbH, Hemau, Germany). This test is similar to a typical leg press commonly found in gyms. According to Maffiuletti et al. (2016) the subjects are instructed to extend their legs as fast and forceful as possible and hold the contraction for 3-5s. After a familiarization attempt, the measurement is performed three times with a rest of 45 s in between. Peak torque will be used as primary outcome.	over the time period of one year of intervention, october to october

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retinal vessel Analysis	Static retinal vessel diameters will be analysed using a Static Retinal Vessel Analyzer (SVA-T, IMEDOS Health GmbH, Jena, Germany). The system consists of a fundus camera (Topcon TRC NW8) and analysing software (Visualis, IMEDOS Health GmbH), allowing non-invasive and non-mydriatic assessment of retinal vessel diameters. Two valid images from the retina of the left and right eye with an angle of 45° and with the optic disc in the centre will be taken. Reti-nal arterioles and venules, coursing through an area of 0.5-1 disc diameter (d) from the optic disc margin, will be identified semi-automatically at higher magnification using special analysing software (Vesselmap 2, Visualis IMEDOS Health GmbH). Diameters will be averaged to central retinal arteriolar (CRAE) and venular (CRVE) diameters, using the Parr-Hubbard formula de-scribed elsewhere (Ikram et al., 2006) and the AVR will be calculated from the CRAE and CRVE. Retinal vessel diameters are generally presented in measuring units (	time period of one year
Blood pressure	Blood pressure will be assessed in a supine position after a rest period of five minutes by use of a validated automated oscillograph (Mindray VS-900, Mindray, Darmstadt, Germany) for use in children and adolescents (Wong et al., 2006) Cuff size will be selected based on the individual circumference of the upper right arm according to the guidelines (Flynn et al., 2017; NHBPE Program, 2004). Blood pressure is measured 3 times with 2 min apart, whereby the last two are averaged and the first is discarded.	time period of one year
Enjoyment of physical activity	To measure psychological acceptance, participants are asked to complete the Acceptance and Fusion Questionnaire for Youth (AFQ-Y). This instrument assesses the willingness to experience private events, values-oriented action, experiential avoidance, and cognitive and emotional fu-sion. The Difficulties in Emotion Regulation Scale (DERS-36) is used to measure difficulties in emotion regulation. Additional information on sleep behavior, perceived stress, and well-being is gathered using the Insomnia Severity Index (ISI), the Perceived Stress Scale-Youth (PSS-Y), and the WHO-5 Well-Being Index.	over the time period of one year of intervention, october to october
Body composition	Body weight and composition in light clothing will be conducted using the gold-standard method, dual-energy x-ray absorptiometry (DEXA), utilizing a GE Lunar iDXA® device (GE Lunar Inc., Madison, WI; software version 13.10). Participants in the study are required to fast for 6 hours prior to the assessment. The analysis will yield both absolute and relative metrics for total body fat mass and fat-free mass. Throughout the assessment, subjects will lie in a supine position (Marra et al., 2019). The effective radiation dose from a single whole-body DEXA (<10 μSv) is similar to the normal background radiation received over one day at sea level.(Shepherd et al., 2017)	over the time period of one year of intervention, october to october

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Power assessment	Power per body mass, determined from a vertical countermovement jump (CMJ), has been shown to be correlated to leg extension strength in children while representing a more natural movement. The CMJ will be performed on a force plate (Leonardo Mechanograph®, Novo-tec medical, Pforzheim, Germany) with arms akimbo. The instruction will be to jump as high as possible. After familiarization, each participant performs 5 trials, with the best of the two trials with <5% difference being used for the analysis. The most important outcome parameter of this test is the maximum power output (peak power) normalized to body weight. The CMJ had a high intra-trial reproducibility (ICC>0.95) in children, whereas inter-session variation has been re-ported to be high in prebubertal and early pubertal children as well (ICC=0.95, SEE=1.92 stand-ard error of estimate).	over the time period of one year of intervention, october to october
Handgrip Strength	The handgrip strength is measured with an adjustable application to accommodate the span of each hand size (Leonardo Mechanograph®, Novotec medical, Pforzheim, Germany). The measurement is performed with the arm held vertically straight, providing a safe and reliable measurement for children (Gąsior et al., 2020). The subjects are instructed to compress the ad-justable application as forceful as possible and hold the contraction for 5s. After a familiarization attempt, the measurement is performed three times with a rest of 1 min in between.	over the time period of one year of intervention, october to october
Acceptance and Fusion Questionnaire for Youth (AFQ-Y)	This self-report questionnaire assesses psychological acceptance in children and adolescents. It measures key components such as willingness to experience uncomfortable thoughts and emotions (acceptance), values-based actions, experiential avoidance, and cognitive/emotional fusion. Scoring: The AFQ-Y consists of 17 items. Scale range: Responses are rated on a Likert scale from 0 ("Not at all true") to 4 ("Very true"). Interpretation: Higher scores indicate greater psychological inflexibility, which is considered a worse outcome.	over the time period of one year of intervention, october to october
Emotion Regulation Scale (DERS-36)	This 36-item questionnaire measures various aspects of emotion regulation difficulties, including emotional awareness, clarity, acceptance, impulse control, goal-directed behavior, and access to regulation strategies. Scoring: Each item is rated from 1 ("Almost never") to 5 ("Almost always"). Scale range: Total scores range from 36 to 180. Interpretation: Higher scores indicate more severe difficulties in emotion regulation, reflecting a worse outcome.	over the time period of one year of intervention, october to october
Insomnia Severity Index (ISI)	The ISI assesses the nature, severity, and impact of insomnia. It includes questions on sleep onset, sleep maintenance, early morning waking, satisfaction with sleep, and impact on daily functioning. Scoring: 7 items, each rated from 0 ("No problem") to 4 ("Very severe problem"). Scale range: Total scores range from 0 to 28. Interpretation: Higher scores indicate more severe insomnia symptoms, a worse outcome.	over the time period of one year of intervention, october to october
Perceived Stress Scale - Youth Version (PSS-Y)	This scale measures the degree to which situations in one's life are appraised as stressful, specifically for children and adolescents. Scoring: Items are typically rated on a 5-point Likert scale. Scale range: Depending on version, generally 0 to 40. Interpretation: Higher scores reflect greater perceived stress, a worse outcome.	over the time period of one year of intervention, october to october
WHO-5 Well-Being Index	This short questionnaire assesses subjective psychological well-being over the past two weeks. It focuses on positive mood, vitality, and general interest. Scoring: 5 items, each scored from 0 ("At no time") to 5 ("All of the time"). Scale range: Raw scores range from 0 to 25, which are then multiplied by 4 to give a final score from 0 to 100. Interpretation: Higher scores indicate better well-being, a better outcome. Scores below 50 may indicate reduced well-being or risk of depression.	over the time period of one year of intervention, october to october
Accelerometer-Based Monitoring	Physical activity is objectively measured over a 7-day period using a wrist-worn accelerometer. This device collects data on: Duration, frequency, and intensity of movement Data source: Integrated gyroscope and accelerometer sensors Interpretation: Data is analyzed in line with age-appropriate activity thresholds (e.g., moderate-to-vigorous physical activity levels)	over the time period of one year of intervention, october to october
Recall-Based Physical Activity Protocol	Participants provide a structured recall of the types of physical activities they engaged in during different parts of the day over the same 7-day period. This qualitative input complements the accelerometer data and offers context about activity types and preferences.	over the time period of one year of intervention, october to october
International Physical Activity Questionnaire - Short Form (IPAQ-Short)	This questionnaire assesses physical activity levels over the past 7 days, including walking, moderate activity, vigorous activity, and sitting time. Scoring: Time spent in each activity type is used to estimate energy expenditure in MET-minutes per week. Interpretation: Higher MET-minutes indicate higher physical activity, a better outcome.	over the time period of one year of intervention, october to october
Tanner Stages Self-Assessment Questionnaire	To assess pubertal development, participants self-rate physical characteristics based on standardized illustrations and descriptions of secondary sexual characteristics (e.g., pubic hair, breast/genital development). Interpretation: Tanner stages range from Stage 1 (pre-pubertal) to Stage 5 (fully mature), allowing categorization into early, mid, or late pubertal status.	over the time period of one year of intervention, october to october

Collaborators and Investigators

• Sponsor: University Hospital, Basel, Switzerland
• Collaborators: University of Basel; Gesundheitsförderung Schweiz, GFCH
• Investigators: Principal Investigator: Ralf Roth, Phd, University of Basel, Department of Sport, Exercise and Health

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2025
• Primary Completion (Estimated): October 1, 2028
• Study Completion (Estimated): December 1, 2029

Study Registration Dates

• First Submitted: March 28, 2025
• First Submitted That Met QC Criteria: April 4, 2025
• First Posted (Actual): April 11, 2025

Study Record Updates

• Last Update Posted (Actual): April 11, 2025
• Last Update Submitted That Met QC Criteria: April 4, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: Overweight adolescents; Youth physical activity; Motor performance in children; Impulse control and fitness; training in peer groups
• Additional Relevant MeSH Terms: Mental Disorders; Nutrition Disorders; Overnutrition; Body Weight; Obesity; Overweight; Pediatric Obesity; Disruptive, Impulse Control, and Conduct Disorders
• Other Study ID Numbers: Now!-Projekt, 2024-01651

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No