A study using a mouse model of eccentric contraction has revealed that icing injured muscles delays muscle regeneration. The discovery was made by a research group including Associate Professor ARAKAWA Takamitsu and then Ph.D. Student KAWASHIMA Masato from Kobe University’s Graduate School of Health Sciences, and Chiba Institute of Technology’s Associate Professor KAWANISHI Noriaki et al. In addition, the researchers illuminated that this phenomenon may be related to pro-inflammatory macrophages’ ability to infiltrate damaged cells. This research raises questions as to whether or not severe muscle injuries (such as torn muscles) should be iced.