The investigators aim to investigate the effect of high-intensity training in patients with facioscapulohumeral muscular dystrophy. Can patients benefit from this type of exercise without muscle damage.

Clinical trials have in recent years demonstrated that aerobic exercise, are both effective and safe in patients with facioscapulohumeral muscular dystrophy. Previous studies have tested exercise at moderate intensity. No studies have so far investigated whether high-intensity-training (HIIT) exercise can increase fitness, or the training will cause muscle damage. However, we know that patients with facioscapulohumeral muscular dystrophy do not get increased muscle damage after a single exercise at high intensity.

Investigators aim to investigate whether patients with facioscapulohumeral muscular disease may increase their fitness and improve their functioning in everyday life without muscle injury in a time-saving high intensity training.

To investigate whether HIIT is safe and effective, three groups of participants are included. Two training groups, one group of patients and another with healthy matched subjects. The training is done on an ergometer-bike three times a week for 8 weeks. One weekly training will be supervised. The training consists of an interval training program (10-20-30). The third group is a none-training control group of patients. This group will undergo the same tests as the two training groups.

To investigate wether participants would continue HIIT training after 8 weeks of supervised training, the two training groups, one group of patients and one group of healthy matched subjects, are tested after additional 8 weeks of home based optional training.

To investigate wether patients with muscular dystrophy facioscapulohumeral will perform unsupervised HIIT training and whether it will be as effective as the supervised training, the control group of patients who did not train the first 8 weeks, is instructed to do home based HIIT for 8 weeks.

Inclusion Criteria:

• Diagnosed with Facioscapulohumeral muscular dystrophy or
• healthy matched control, matched for age, gender, BMI and activity level.

Exclusion Criteria:

• More than 1 hour cardiac exercise weekly before inclusion.
• Pregnant or breastfeeding women.
• Physical or mental condition, which could influence the results.
• Participating in other studies, which could influence the results.
• Physical or mental condition, which prevent participating in the study protocol.