A treadmill comprising: a frame ; a deck assembly including a front end portion pivotally connected to the frame, the deck assembly positionable in an operating position and a storage position; a first tube connected to one of the frame or the deck assembly, the first tube defining a first engagement feature and a second engagement feature ; a second tube connected to the other of the frame or the deck assembly and slidably connected to the first tube; and a lock mechanism operative to lock the deck assembly in the operating position and the storage position, the lock mechanism comprising: an engagement member operatively connected to the second tube and engageable with the first engagement feature and the second engagement feature of the first tube; wherein: engagement of the engagement member with the first engagement feature locks the deck assembly in the storage position; and engagement of the engagement member with the second engagement feature locks the deck assembly in the operating position while allowing incline adjustment of the front end portion of the deck assembly relative to the frame during operation of the treadmill; a lift assistance mechanism operatively connected to the frame and the deck assembly, characterised in that the lift assistance mechanism is at least partially received inside the first and second tubes. a frame ; a deck assembly including a front end portion pivotally connected to the frame, the deck assembly positionable in an operating position and a storage position; a first tube connected to one of the frame or the deck assembly, the first tube defining a first engagement feature and a second engagement feature ; a second tube connected to the other of the frame or the deck assembly and slidably connected to the first tube; and a lock mechanism operative to lock the deck assembly in the operating position and the storage position, the lock mechanism comprising: an engagement member operatively connected to the second tube and engageable with the first engagement feature and the second engagement feature of the first tube; wherein: engagement of the engagement member with the first engagement feature locks the deck assembly in the storage position; and engagement of the engagement member with the second engagement feature locks the deck assembly in the operating position while allowing incline adjustment of the front end portion of the deck assembly relative to the frame during operation of the treadmill; a lift assistance mechanism operatively connected to the frame and the deck assembly, characterised in that an engagement member operatively connected to the second tube and engageable with the first engagement feature and the second engagement feature of the first tube; wherein: engagement of the engagement member with the first engagement feature locks the deck assembly in the storage position; and engagement of the engagement member with the second engagement feature locks the deck assembly in the operating position while allowing incline adjustment of the front end portion of the deck assembly relative to the frame during operation of the treadmill; engagement of the engagement member with the first engagement feature locks the deck assembly in the storage position; and engagement of the engagement member with the second engagement feature locks the deck assembly in the operating position while allowing incline adjustment of the front end portion of the deck assembly relative to the frame during operation of the treadmill; the lift assistance mechanism is at least partially received inside the first and second tubes. <EOS>