these self-styled athletes have banged their brains into the ground so frequently and furiously , their capacity to explain themselves has gone the same way as their natural instinct for self-preservation . 
(ROOT (S (S (NP (DT these) (ADJP (NN self) (HYPH -) (VBN styled)) (NNS athletes)) (VP (VBP have) (VP (VBN banged) (NP (PRP$ their) (NNS brains)) (PP (IN into) (NP (DT the) (NN ground))) (ADVP (RB so) (RB frequently) (CC and) (RB furiously))))) (, ,) (NP (PRP$ their) (NN capacity) (S (VP (TO to) (VP (VB explain) (NP (PRP themselves)))))) (VP (VBZ has) (VP (VBN gone) (NP (NP (DT the) (JJ same) (NN way)) (PP (IN as) (NP (NP (PRP$ their) (JJ natural) (NN instinct)) (PP (IN for) (NP (NN self) (HYPH -) (NN preservation)))))))) (. .)))
(ROOT (S (S (NP (DT ) (ADJP (NN ) (HYPH ) (VBN )) (NNS )) (VP (VBP ) (VP (VBN ) (NP (PRP$ ) (NNS )) (PP (IN ) (NP (DT ) (NN ))) (ADVP (RB ) (RB ) (CC ) (RB ))))) (, ) (NP (PRP$ ) (NN ) (S (VP (TO ) (VP (VB ) (NP (PRP )))))) (VP (VBZ ) (VP (VBN ) (NP (NP (DT ) (JJ ) (NN )) (PP (IN ) (NP (NP (PRP$ ) (JJ ) (NN )) (PP (IN ) (NP (NN ) (HYPH ) (NN )))))))) (. )))