Yes they are still effective. My guy is a balanced back. Thanks to AEQ he has 8 PT and 9 Juke lol but he still tops 100 speed 70 agility 60 strength and carrying. Anyway, no your running style does not decide which SAs trigger and will not make them trigger any less. Effectiveness maybe. I mean, if you try to trigger Power Thru (lowering your shoulder) WHILE trying to dodge a defender, its effectiveness may be toned down. But in all, running style does not effect the rate or which SAs are fired only the situation and your ability to pull it off. Not sure really because my back uses PT and Juke quite efficiently running on -80 Elusiveness. I like the balance so that he cuts up the defense and when he is faced with a defender can still lower his head and burrow through a guy or two. That's just my experience though and generally most the people here would lean towards a specialist with a statement such as "Why be mediocre at everything when you could be really great at one or two things (I.E Speed+Agility or Power+Carrying). It's up to you but my back has been fairly effective. One season I believe he had like 500 yards but still had 20 rushing TDs lol