Switching to running in the winter has a ton of benefits, from shorter more time efficient workouts to increasing bone density and balance skills. You also can often see things in a different light not moving at 20 mph on a bike, with the same old trails taking on a whole new perspective.
The most important consideration for cyclists is the same awesome aerobic engine that we’ve developed riding all those hours can encourage us to run too hard and too long when we start up. All the supple muscles and connective tissues that are accustomed to low impact cycling need time to get used to high impact loads, especially in the lower extremities.
Changing quality shoes very frequently, running on dirt trails, and restraining yourself to very short easy sessions at first will get you up to speed safely. I like to have athletes start with 10 minute runs the first week, and really listen to their bodies. Hobbling around for a week or worse because you cracked off a race pace 10k out of the gate won’t help you achieve your long term goals, so really be conservative.
Swimming, surfing, or paddle boarding are utterly challenging for most endurance athletes due to their general lack of upper body muscle mass. On the positive side this can be exactly the break from the bike that cyclists need. These sports can be great for lengthening the body out and learning to control the breathing under stress when inevitably getting submerged or splashed in the face with water. Often I like to have racers in extremely cold climates do a gym day finishing off with a 20 minute swim indoors.
Cross Country Skiing
Cross-country skiing, like swimming, is a great full-body workout. It not only is an aerobic workout, but also builds upper body strength, balance, and coordination.
Downhill Skiing and Snowboarding