Tissue and blood samples Before the working session will be commenced blood samples will be collected together with muscle biopsies in order to determine the content of plasma glucose, plasma insulin, and muscle glycogen before commencement of the bicycling workload. Further blood samples will be collected at 0, 30, 60, 90, 120, 150, 180, 210 and 240 minutes after completion of the working session, and further muscle biopsies will be collected at 0, 120 and 240 minutes after completion of the working session.