I had read this article in the past and from mine and several others who have been involved in freediving education point to several factors that can reduce greatly the chances of DCS:
1) NEVER breathe off of compressed gas while freediving - if you have a bailout system, like a spare-air, and you use it while freediving, you are now a tank diver and all rules regarding how you should ascend apply - ie; you are done freediving for the day when you reach the surface.
2) Unless you have a good reason to dive to those depths repeatedly, don't.
3) Allow yourself at least 5 minutes to recover from a dive - if you dive to those depths like 120 feet repeatedly, allow at least 10 minutes recovery to off gas any nitrogen that may have accumulated in your system.
The repeated diving to those depths is what increases your chances of DCS.
This by no means guarantee's that you won't get DCS, but it will greatly reduce the risk of it occuring.
