Deadlifts are slated into many leg day routines. The exercise is excellent for developing lower body muscle size and strength. Because of the importance of deadlift form, a study published in the Journal of Strength and Conditioning Research compared traditional barbell deadlifts to two types of walk-in deadlift machines using both experienced and inexperienced subjects.
At the start of the lift, trunk angle for conventional deadlifts was 23.7 degrees compared to 29.9 and 32.4 degrees, which is significantly more upright. Knee angle was more flexed with machines, but muscle activity in the glutes was lower with machines shifting work to knees. So while machines can help reduce stress on your lower back, the added stress on knees might keep this option from being considered a long-term solution.