"It is a complicated issue. It is truly a complicated issue, with a wide range of views, truly a wide range of views," Jean-Pierre said. "There is no 'yes or no' answer to this, it is complicated. There is a rule that the Department of Education [DOE] has put forward, and we're going to let that process move forward, and again, we want to make sure that while we establish guardrails with this rule, we also prevent discrimination, as well, against transgender kids. But again, a complicated issue with a wide range of views, and we respect that."
"Absolutely no reason for the Biden admin to do this," New York Representative Alexandria Ocasio-Cortez wrote. "It is indefensible and embarrassing. The admin can still walk this back, and they should. It's a disgrace."
"Honestly, this move by Biden to push a rule on trans kids in sports is not only a backwards betrayal, it [forces] us to have to spend our time dealing with god d*** sports instead of criminal bans on our healthcare," Alejandra Caraballo, a civil rights attorney and LGBTQ+ advocate, wrote. "He could have just done nothing. This is legitimizing transphobia."
The mOsT PrOgReSsIvE Administration in History™ 
"A complicated issue with a wide range of views, and we respect that" Fuck off out of here with that "centrist" nonsense. There's nothing complicated about it, and it's not an issue unless you want to turn it into one and want to appeal to people's emotions like Republicans are doing. It was only a matter of time before they'd start throwing trans people under the bus. I guess with the coming elections it's as good a time as ever.
Absolutely, though you will never be engaging 100% one and 0% the other and there are differences between individuals (due to hormones, etc.). Isometric exercises like planks are mainly slow twitch and bursts of exertion like in burpees or sprints or powerlifting are more short twitch.
You will always be training both, but you can lean one way or the other.