Before tilt-in-space wheelchairs, reclining wheelchairs were dominant when a person was a high risk for pressure sores and needed to change their position in the chair during the course of the day.  The drawback of reclining wheelchairs is that when reclining the backrest, it causes a sliding effect on the user.  The back shears against the users pelvis and against their back.  This can cause sores on the back and pelvis if the user's skin is susceptible.  Also recliners can cause a client to slide down and out of the wheelchair.  

Since the introduction of the Tilt-in-Space wheelchair; recliners have taken the back seat.  The only time recliners are prescribed over tilts is when a client needs to recline for feeding, daily activity or severe deformity.  

Tilt-in-Space takes a person sitting upright and tilts the whole seat frame back.  This allows for the pressures on the buttocks to be redistributed to the back of the user.  The tilt-in-space also allows for correct posture.  The tilt with the assistance of gravity helps force a users back, and hips to the rear of the wheelchair helping maintained midline posture.  With tilt there is no shear effect since the user's body never changes position against the support surfaces of the wheelchair. 

There are chairs now that offer both tilt and recline.  This can be useful when working with a client who has severe deformity and is at risk of pressure.