Easily the most legitimate excuse on the list, the threat of cold related injury can scare even the most dedicated Aspenites off the road to fitness. Though very important to be aware of, fear of these problems need not stifle your progress. Serious conditions like hypothermia and severe frost bite make for an easy cop-out, but are even easier to avoid in the first place.
Proper warm up:
Warm up to stretch out, don't stretch out to warm up.
Your warmup is instrumental in preventing injury, especially during winter, but recent studies have revealed the ineffectiveness and possible danger of classic pre-workout stretching routines. The static stretching you used to do in gym class (ie. touching your toes for thirty seconds) can destabilize joints, increasing the chances of injury. So what should you do? Favor an active warmup followed by dynamic movements, reserving static stretches for after exercise:
- First, spend a few minutes warming the body and lubing up your joints by going on a light jog, doing some body-weight squats and push ups, skipping rope, etc. Get blood flowing to all parts of the body, especially the areas you will be targeting.
- Now move on to dynamic stretches, focusing on movements relating to your workout. This will prepare your body for the work it will be doing.
As for what dynamic stretches to do, I recommend starting with the official Crossfit warmup (video HERE), and modifying it to fit your workout (ie. including shrugs and arm swings before a shoulder workout). More run-specific movements can be found in this video. If strength training is part of the plan, do a couple light sets of the exercises you will be performing, gradually increasing range of motion and intensity. Keep in mind: this is just the warmup—exhausting yourself here won't help workout performance.