If you travel a fair amount for Work (or whatever) there’s one exercise that you can easily do anywhere - running .   Just bring along some shorts and shoes and you’re ready to rock.  I usually maintain a small amount of running form so that when I’m out of town for work for a week or two, I can always get in an hour of running without feeling it too much the next day.  I usually run 30-45min once a week which is enough to keep those specific muscles, joints and ligaments in good enough shape to go for a run when my bike isn’t around.

I’m currently away for a few days on vacation on the Gold Coast and it wasn’t feasible to bring my bike.  Unfortunately  I  have not kept up my running form over the past few months.  As an arrogant cyclist I figured that I could smash out a 10km run with everyone else.   No problem…at the time.  Now, 24hrs later, my quads, calves and IT bands are so soar that I barely stand up!   That’s the problem with having a big aerobic system and absolutely NO muscular conditioning for running.

So, is training for cycling by running beneficial?

The amount of running you can comfortably maintain without affecting your cycling is a very individual thing but  in short,  moderate running is very good for your cycling.   Mainly because it’s an efficient way to get in an excellent aerobic workout in a short amount of time.   People like ourselves, who have regular lives outside of cycling, don’t always have time to do a 2-3hr Ride but we still want to get in a good workout. A quick run can achieve this.  However,  doing a lot of running will definitely hinder your cycling.    This is mainly due to the opposite types of muscle contractions that running produces vs cycling and the resulting chance of injury.  Cycling vs running also train completely different sets of muscle groups.

Running is one of the highest injury prone sports due to the high impact stress associated with it.  Running on softer surfaces such as grass will moderate some of the risk of running.  Many cyclists I know used to be runners but switched sports due to injuries.  One thing that causes running injuries is eccentric contractions.  In an eccentric contraction the muscle lengthens as you attempt to shorten it (this is why my quads hurt so much going down the stairs, but not up).   The calf and quads experience this with every step while running.  Basically, the muscle is being pulled apart.

On the contrary, cycling relies on concentric contractions - meaning the muscle shortens as it contracts. This is what most people typically associate with a muscle contraction.  Since cycling is a low impact sport it allows you to go out for longer and put yourself through more suffering than most other sports will allow.  Your energy will wane and your mind will give out long before  your joints, muscles, ligaments, etc will concede.

In the end, running does not mimic the demands of cycling, and the golden rule is keep your cycling training specific . Cycle specific training will not only condition the appropriate muscles (in terms of physical and biochemical properties) but will also adapt the appropriate neuromuscular pathways. However, I feel that keeping a small level of running fitness is beneficial for times when circumstances don’t allow for a ride. A run can be a great aerobic alternative.  I often heard that a half hour run is equivalent to a 2hr ride.

Now, I’m going to the beach to even out those tanlines and let my poor legs recover.

Source: http://cyclingtipsblog.com/2009/01/running-to-supplement-your-cycling-training/