My son is a Ranger. Those sit ups, pull ups, etc come at the end of one of the 3 two week long phases. Each phase gives candidates about 1 hour sleep and two MRE’s per day with constant physical and mental activity that borders on the ridiculous. There are some documentaries on cable you can watch, but my son said they left out the hard parts. Go for two weeks like that and then try to pass all of those physical requirements in a day and you may change your mind about how tough it is. It is said to take 6 years off of their life expectancy from the stress to their body and organs. The main difference between the Ranger training and Seal training is that Seals do a lot more in the water.
He also got through Ranger school before they let women in. He knew it was coming and was proud to get through before they messed with the requirements...don't know if they did or not.