Sports medical experts recommend considerable amounts of regular physical activity in order to improve strength, motor control, endurance and flexibility. However, only a small share of the population is able to meets the corresponding international guidelines. One reason for this is supposed to consist in private scheduling problems and the high time expenditure. Against this background, high-intensity intermittent training methods with short durations have become popular.

The present study aims to evaluate the effectivity of a high -intensity functional circuit training (the FIT15 program) in improving body function.

Thirty healthy individuals will be included in the randomized, controlled two-armed parallel group trial. In the intervention group, the participants will perform the FIT15 program, a group-based high-intensity circuit training based on functional movement patterns (e.g. squats, push-ups, burpees, jumps, rope-skipping). The training will be carried out three times a week, each 15 minutes for a total of six weeks. In the control group, the participants will exercise three times a week (in total for six weeks) at moderate intensity on an ergometer according to the cardiopulmonary exercise guidelines of the American College of Sports Medicine. Outcomes assess prior and following the six-week training period encompass body fat and muscle mass (bio impedance analysis), aerobic exercise capacity (spirometric exercise testing including lactate analysis), postural control (force plate), maximum strength of the leg extensors and shoulder muscles (1 repetition maximum) and psychometric variables (e.g. physical activity readiness questionnaire).

Inclusion Criteria:

• healthy
• subscribing informed consent

Exclusion Criteria:

• Drug intake in the past 48 hours
• Pregnancy
• Muscle soreness