i'd look into getting a compression knee band. it'll hold your knee cap tight, and won't allow slipping. i had the same problem, and i got a knee band, and it feels great. http://www.supports4u.com/Fla/fla-ksta.jpg i also invested in some new balance 902's, which have been getting great reviews from runner's world (shoe of the year 2007). they were about $100 from the new balance online store (i shopped around for the price), but they feel amazing, and i've decided to make the switch 2 weeks before my marathon. they just look cool too, bright orange. http://www.barlou.com/running/img/new-balance/nb_902_homme_orange_0107_gm.jpg