for specialized, well-trained athletes, cross-training may be counter-productive. but for those of us who sit in a chair on a daily basis and grind out an honest day's work before we hit the less beaten path, or at least for ME, cross-training is as important as it is time consuming.
i say time consuming because other people may ONLY want to run (for example). for them, anything that gets in the way of running, which is done in the precious commodity called "free time", is a bad thing. i happen to really love cycling. i've been cycling longer than i've been running. the thing i think i like most about cycling is that i can do it for hours on end without feeling like i'm going to crumble into pieces. i cannot do that on the run yet. i'm training to be able to do that, but i'm not there. but i think it's important, when training to do that on the run, to teach your body how to suffer for hours on end.
i've learned through unfortunate experience that you cannot simply go from someone who runs 5ks to someone who runs marathons. instead of "you", i should say "i"... maybe some people can do it, i cannot. i think modern conventional wisdom indicates a 10% increase is about right per week for mileage, nothing more. after a good first half of the year of training, i tried to ramp my mileage up more quickly than that. now i sit and type more than i run due to injury.
reason number 1 why cross training is important to me:
when i cross-train, i get injured less. during the years i was racing triathlons, i don't remember ever being injured. i remember a lot of pain, a lot of soreness and lot of weeks when i decided to take it easy due to a feeling of being burnt out or physically wasted, but i didn't get injured to the point where i needed to stop for any significant amount of time.
the first half of this year, i cycled nearly as much as i ran. i kept a pretty consistent running plan and cycled on the off days, sometimes cycling on days i ran (a "brick"). it wasn't until todd brought up the idea of doing a marathon that i started to focus on only running, ramping up the miles and staying away from the bike. obviously, it's a combination of ramping miles and forgoing the cross training that led to injury (plus, i've been complaining about the calf for quite some time, so the seeds of this were already there). but i do think if i kept more consistent about the cycling, i could have ramped the miles a bit faster (but still not as fast) and kept myself uninjured.
which leads me to the number 2 reason why cross training is important to me:
building a cardio-vascular base, a tolerance for pain and teaching your body how to burn fuel over the long "run". i guess that's more like 3 reasons, but they all lead to the same thing... preparing the body for going longer. i've found that swimming is a very intense cardio-vascular workout and over the past few weeks of swimming, i feel like i've certainly maintained, if not improved my cardio by doing increasingly longer pool workouts. i'm not a "pool runner", which seems a bit ridiculous to me, but a lap ticker... lap after lap of mind numbing crawl swimming. the most significant jumps i made in increasing my pace (back in the day) came after i started adding serious swimming workouts to my routine.
out on the bike you go through periods of high-heart rate, lactic acid-injecting climbing followed by mellow downhills, with the grinding flats in between. Massachusetts doesn't offer high mountains, but there are plenty of rolling hills to be found, plenty of climbing to be done. it's a lot of little climbs, with a cumulative effect of crushing your legs and forcing them to recover quickly. i think it's good to teach the legs to endure, produce, recover and then to do it all over again.
on a long ride, you also start to learn about the importance of nutrition and hydration. this weekend, for example, i went out for a nice long ride where the bulk of my climbing was in the first half of the journey. i felt great through all the climbs, good enough to push the pace a bit in the flats in between. but when i got to flatter roads, i started to tank... my body had burned up whatever fuel was left in the tank and needed more... and it was very hard to take on calories. my stomach didn't feel all that great, i had no appetite, but i managed to force down some food a bottle of water. not long after that, i felt good again. i think it's very good for the long run to teach your body that cycle.
maybe i'm just trying to find some way to be happy about my current non-running state of being... but the more i bike and swim, the more i'm learning to trumpet these activities as crucial to my well being and preparation for running longer distances. most importantly, i'm able to get out there and exercise... and THAT is certainly something!!