Why are there only 1 x 5 Deadlifts in Stronglifts 5x5 ?

Overall volume

Stronglifts is a program that already has a considerable amount of volume in a week on the big three lifts compared to other more advanced programs. The squat is being emphasized most, as this is the movement which will have the most carry over to overall fitness and strength performance. The reason for this is that the back squat as incorporated partially or fully in other many other movements in fitness and it also works on your overall mobility.

This leaves not a lot of room for a big amount of heavy deadlifting. Most programs actually tend to have lesser repetitions on the Deadlift compared to the bench press, squat, overhead press, barbell row and other beneficial movements for strength and muscle development.

Most taxing lift

The deadlift is one of the most taxing movements you can do with a barbell as you will most likely move the most weight per repetition. This is especially challenging for your nervous system. Usually, it is not the muscle system that fails a lifter on the deadlift, it is the nervous system that just refuses to fire any more impulses to the overall body to initiate heavy fibre twitching / contraction, to get the load of the ground.

Protect lower back

If done incorrect and even if executed perfect, the deadlift is a strain on your lower back and discs. Less deadlifting therefore is not a bad thing when you consider that you want to stay in the game for the long run. I personally deadlifted too much, too heavy in 2016 when on Jim Wendler 531 and had to pay the price by currting the deadlift out altogether for about four months to recover.

Protect your shins

A correctly executed deadlift will leave the barbell very close to your shins. If yu do not wear Deadlift socks or any other pair of socks that goes up to the knee, you most likely will scrape your shins doing heavy deadlifts. Not a pleasant outlook if you have to do that every day and no time to heal