Does cycling improve stamina or any other physical characteristics?

Question

Background info:

I've been practicing shotokan karate for 9 years now and loved exercising in general. Due to various reasons, I moved to a different region and started japanese jiu jitsu 5 months ago (there are no karate dojo's around). Since then, because of the current location, I must ride a bike for at least 8 kilometers almost daily (sometimes even more). I know this might not sound like a lot, but before moving, I hadn't even touched a bicycle in years and now it's my main mean of transportation. Couple that with two training sessions a week of jiu jitsu (which I sometimes have to skip for my schedule does not allow me to). After 5 months, I noticed a change in my thigh and calf muscles (a bit thinner and more pronounced, not by much, they were very "pronounced" even before I started cycling).

Regarding the terrain, it's mostly flat but there is an steep overpass over an highway plus a 100 meters region which is pretty steep as well.

Question:

Does riding a bicycle for at least 8 kilometers a day (or any substantial number of km for that matter) improve stamina in karate or martial arts in general? Are there any other benefits from it?

The jiu jitsu training (at least from my perspective) teaches a different kind of energy "output" for the feet compared to karate, as in karate matches the legs are continuously under use compared to jiu jitsu (just my observation so far).

Answer 1

Cycling will initially improve your general fitness, (especially stamina, general cardiovascular). After a while you will reach a general plateau of improved fitness (unless you keep increasing the cycling distance/intensity).

The issues for martial arts fitness is that cycling only uses certain groups of movements for a repetitive action. So while you may find an increase in muscle in certain areas you may start to lose it in others (as carrying muscles for lifting your legs to the side are redundant and may actually work against you in cycling).

Another issue is that cycling is an endurance activity, you output a similar amount of energy constantly for several minutes (or hours if you go longer distances). Martial arts often require that short sharp movement (Karate especially) so whilst you may feel fitter, activities like sparring where you are working beyond the energy output of cycling can quickly wipe you out.

Flexibility - Cycling will tend to hurt your flexibility as it only requires a short motion and it is too common to get to your destination, park up the bike and forget to stretch. It also builds muscles good for that forward and backward motion that may hinder side to side motion (as it is unnecessary).

My recommendation? - Cycle! its good for you and it helps with your general fitness, but make sure you pay attention to the areas that cycling does not work. Sparring drills and anaerobic exercises (e.g. sprints) to keep the fast twitch fibres working. Chest work to keep in proportion. Kick practice - to ensure you are not just building muscles good for rotating those pedals.