No need to go technical. Might be this your first time to see such price movement recently so you are confused.

There should be no such thing in your mind like "bitcoin vs altcoin" during their upward and downward trend. Depends on what altcoin you are currently trading, you will really notice that while bitcoin is pumping, your altcoins can't ride the trend. It's usual. What you need to do is to think of a strategy for a situation like that since believed me, there will be lots of times you will see that kind of price movement while you progress in the crypto world.