You might remember that in one of my posts in this blog about 3 years ago, I raised the issue of possible negative impact of frequent cold water immersion (CWI) on long term adaptations to training. For your information this is the post http://georgenassis.blogspot.com/2011/07/some-thoughts-on-use-of-water-immersion.html
This speculation, at that time, was based on the fact that CWI seems to suppress inflammation which is part of the exercise training-induced adaptation process.
The group from Australia tested this idea in 21 men split in two groups. One group performed high-intensity resistance training twice a week for 12 weeks plus lower body CWI for 10min post exercise. The other group performed the same training but instead of CWI they cycled at low intensity for 10min post-training. Training adaptations were assessed by measuring changes in maximal isometric torque and rate of force development (RFD), isokinetic dynamic strength, leg press and knee extension strength.
Their results showed that training-induced changes in isometric torque and isokinetic torque, RFD and knee extension strength were signifi cantly smaller in the CWI group.
Based on these findings, it seems that regular CWI may attenuate the exercise training-induced performance improvements.
Roberts et al. MSSE 46(5): S192