Deadlift why the first pull is always the most difficolt?

When I deadlift I feel that my first lift in a sets of 5 reps is always the most difficolt, the other 4 reps come easily...why?

Idk, first rep is the one that follows a period of rest.

Wish I could have that. Every rep I do comes with pain from start to finish of the set.

In honesty though it probably has to do with the fast that you approach the first rep good and loose, but other reps are done while your body is wound for action.

If I can get the first one up, I usually can get all 5. I think it's the adrenaline rush of accomplishing a weight I wasn't sure I could do. Failed at 355 today, pissed me off and broke my heart. Going to get it next time though!!!

For me, the first pull from the floor is hardest because one I'm not in the perfect position for some reason I'm not raking my shins on the first pull, and two I never really completely unload my legs when I set the weight down. I don't like to bounce the weight so I go down slowly until I touch the floor then explode back up. I'm in perfect form and my legs are preloaded with weight. As least that's how I feel in my head and hope I made sense explaining it.

Yeh its just where your muscles become "accustomed" to the current weight. At this point its your will against the weight. But. Its not just dead lifts you see this in. I've come across many ppl who need assistance on first n last reps of 6 to 8 on their upper end. I sometimes do with 50kg dumbbells.
which reminds me. I gotta tell my gym to get heavier dumbells

It's your cns not firing completely on the first rep. If you are lifting very heavy for a set of five, make sure to get psyched before pulling. Watch some powerlifting meets on YouTube to get an idea of what I mean.

because you are not dropping the weight totally, you start on the ground but when you go lower you drop it on the ground and use the rebound to make it easier.

Don't use the rebound and let it all go. Its like doing 10 set of 1 rep. with no pause between.