I went out for my run this morning and it's the coldest run so far. I did my normal fast 8 min warm up walk. Threw my arms around a bit to get everything moving. Then set off. Just after the 1k. My calves started seizing up. I kept running for a while then I had to stop and stretch them out for about 40 sec. I finished my 30 min run and was ok after that. Was it down to the cold do you think or getting over my cold. If it's the cold what's the best way to stop it happening again? Any suggestions please.