The goal of this cross-sectional study is to compare able-bodied peers to adolescents and young adults with cerebral palsy (CP) who have been regularly performing high-intensity functional training for almost two years.

The main research question is: is structured, long-term exercise training able to compensate strength and cardiovascular deficits in adolescents with CP compared to able-bodied peers?

The pilot study investigating the effects of a functional exercise training in adolescents and young adults with cerebral palsy (CP) showed increases in strength, power, daily function as well as cardiovascular health. In order to establish the origin of the improvements and its broader effects, we wish to conduct follow-up measurements to the pilot study. These follow-up measurements would establish whether the positive changes in physical performance are due to neural or muscular changes (or both), and shed more light on how therapy should be performed and prescribed in adolescents with CP. Additionally, we wish to measure their aerobic capacity as well as examine their microvascular health. For this cross-sectional analysis, the participants of the CP-FIT Pilot Study who continued to train on a regular basis will be compared to age-matched peers in order to establish whether their strength and fitness deficits compared to peers can be compensated through structured and progressive functional exercise training.

Inclusion Criteria:

CP Individuals:

• Diagnosis of CP.
• Between 14 and 26 years of age.
• Gross Motor Functional Classification System (GMFCS): I-II.
• Cognitive abilities must include: Ability to verbally or non-verbally communicate pain or discomfort; Ability to attend testing and; ability to understand and follow instructions. All included participants are capable of making decisions on their own and no not show any signs of mental or cognitive limitations.

Healthy peers:

- Between 14 and 26 years of age.

Exclusion Criteria:

CP Individuals:

• Any surgery or botulinum toxin treatment within 6 months prior to the measurements or scheduled during study period. Other medications can be continued as prescribed by the participants' physician.
• Known cardiovascular or pulmonary diseases that have not received medical clearance to participate in physical exercise.
• Uncontrolled seizures or epilepsy.
• Inability to conform to the above mentioned cognitive and physical abilities.

Healthy peers:

• Diagnosis of congenital heart defects, pulmonary diseases or any neuromuscular disorders or diseases.
• Diagnosis of any acute diseases.

The group adolescents with CP consists of individuals from the CP-FIT pilot study who have both continued or discontinued their training after study completion. Healthy peers are age- and sex-matched able-bodied peers.

No IPD will be made public. Group data will be analysed for publication after study completion.