Whole body cryotherapy at ­220 to ­319°F (−140 to −195 °C) done 1 hour after plyometric exercise (squat jumps and leg curls) showed improvements in a variety of performance measures up to 72 hours after the treatment. These improvements include: power at the start of the squat jump, and squat jump work up. In addition, pain measures (both at rest and at the next squat jumping session) were also improved.

The next question is what happens if cold exposure occurs immediately after resistance training during that peak pro inflammatory process? One study has shown that it may actually blunt some of the long­term muscle hypertrophy benefits, at least if you’re doing cold­water immersion. Men that performed leg presses and squat jumps twice per week and then immediately engaged in 10 minutes of cold­water immersion (in other words, at the point of peak inflammation) had only ⅓ of the increases in muscle mass in their quadriceps 10 weeks later compared to those that did no cold water immersion post­training. In addition, after the ten weeks of training, muscle strength was significantly lower compared to the control group, they showed smaller increases in type II muscle fibers (required for very short­duration, high­intensity bursts of power), and all of this coincided with a reduction in biomarkers that are usually associated with hypertrophy, including the activation of satellite cells. Basically, if you were looking to make the argument that cold stress, especially cold­water immersion, should be avoided after strength training… this last study mentioned would be your holy grail. Not just because of the compelling results that the authors demonstrated, but also because they cited other studies that showed similar results with respect to cold exposure and hypertrophy, including some that employed clever investigative methods like having participants do hamstring curls but only immersing one leg in cold water and then going on to measure the difference in hypertrophy between legs afterward.

However, in every single case, both in this study and all of the similar ones cited, there is one singular, unifying theme: the method of cooling whether we’re talking about cold­water immersion, icing, or otherwise, was generally applied immediately after training, So that leaves us with a few open questions, but the most important one is this: would we still have seen the blunted or reduced hypertrophy training if cold­water immersion was done at literally any point other than immediately after strength training? I don’t know the answer definitively because no study has investigated this yet, but it’s an area I hope future studies will illuminate for us, especially in light of the fact that the occasional cold stress seems to have the possibility of conferring benefits in many other respects. The fact that the first hour after exercise, in particular, stands out as an important anabolic window, at least in terms of the endocrine response, may also be especially meaningful in the context of cold exposure and strength training.

For now, it would seem extremely prudent in the context of strength training to exercise caution in how, and especially, when you time any of the various cold modalities whether we’re talking cryotherapy, cold­water immersion, or even the use of cold packs.