Reading a poem in "sprung rhythm" is like driving with someone who has just gotten his or her learning permit. This person hasn't learned to give a steady amount of gas to keep the car moving at an even speed. He alternates between putting the gas pedal to the floor and slamming on the breaks. The rhythm of the poem is stop-and-go: gas! brake. gas! brake. gas! brake. We don't mean to suggest, though, that Hopkins is as inexperienced as a learning permit driver. In fact, Hopkins has one of the most unique styles in English poetry.
Look at all the adjectives in the second stanza, each followed by the pause of a comma or semi-colon. As the driver of the poem, Hopkins puts a mini-brake after each of those words. In other places, he adds extra words to keep the poem hurtling forward. In line 3, he describes "trout that swim," which makes us wonder: "Are there trout that don't swim?" Of course not. There are no incredible walking trout. The last two words are redundant in meaning, but necessary for the rhythm.
The same principle holds for line 6, where Hopkins writes, "gear and tackle and trim" instead of "gear, tackle, and trim." Notice how the first version sounds much quicker. Reading "Pied Beauty" provides all the excitement of being a first-time driver, except that Hopkins is really an experienced veteran with the poetic equivalent of a perfect driving record. Plus, you don't have to fear for your life, which is nice.