The participants in the intervention group performed a @-week arm-crank exercise program , @ sessions/week , consisting of warming-up ( @-@ min ) followed by a main part in arm-crank ( @-@ min -LSB- increasing @ min and @ seconds each three weeks -RSB- ) at a moderate work intensity of @-@ % of heart rate reserve ( HRR ) ( starting at @ % and increasing @ % each three weeks ) and by a cooling-down period ( @-@ min ) .