Is it possible to increase cardiovascular fitness through strength training?

An idea dawned on me a couple weeks ago about that has stayed in my head like a “thorn in the mind”.

My question is, “Could it be possible that having stronger legs will force the cardiovascular system to also get stronger?”.

I’ve noticed a big improvement in my cycling from working on my main weakness which is strength. When I used to do my threshold efforts before it would be my legs that where burning and failing that slowed me down. Granted my heart rate was sky high as I was riding at threshold, I felt like when it came down to it, I could have kept pushing harder, but my legs just wouldn’t do it, they where spent.  Another big clue was that after doing a short time trial and riding until failure then recovering my legs felt like butter, they where done, even riding slow my legs would feel weak for the rest of the training session. It’s like once I pushed my leg muscles past a certain point, that was it, there was not coming back, the muscle had failed not my cardio system.

The biggest thing to improve with cardiovascular improvement is your heart muscle and it’s stroke volume. But you can’t lift weight with your heart muscle, you can’t make your heart muscle do squats or bench presses. So what is the best way to work the heart muscle? Is it through riding miles and miles of  riding? Or riding intervals? Almost everyone that I asked in a recent survey I did agrees that intervals are one the best known ways to get faster, but why? Did you every stop to wonder how intervals change your body?

  1. they make your leg muscles stronger
  2. they make your heart muscle stronger
  3. they also cause other adaptions but I think the first two are the main improvements

Now it would seem to me that the heart and your legs would have to be somewhat balance to match each other’s ability. It would seem strange to me that someone with skinny little legs that can barely sustain 15mph pace would need or have, or be able to develop a big strong heart with a large stroke volume. You’re body’s muscles don’t have the ability to build up enough demand to stress out your heart enough to make it burn and want to grow bigger and stronger.

I guess it would be possible with a lot of effort, maybe by running or doing something that used more then just your legs muscles, maybe like running or swimming or cross country skiing, to force your “fuel pump” to work overtime and get stronger. But from what I’ve experienced in cycling training is that it’s easier to blow your leg muscles out before your cardio system is exhausted. I think running is “better” for cardio then cycling for a lot of people because the muscular strength demand is less and spread across the whole body, both the legs and the upper body, so the demand for the heart to feed all the those muscles and to feed your legs which are moving fast but with little resistance cause you’re heart to work hard. I think to get an equally hard cardio workout on the bike requires leg muscles that are fairly strong, but more importantly have strength endurance, the ability to pedal hard for long periods of time.

Another thought too is that spinning at a faster RPM can also help target the heart muscle and cardio system better. But when riding for maximum speed I find that the effort is balanced over the cardio and leg muscles for the most part, and depending on the rider they may be riding at a faster RPM easier gear and using more cardio, or using more muscular strength by riding a lower rpm harder gear. 

I guess the counter arguments would be that

  1. because of your weak cardio system, it’s making your legs fail prematurely, if you had a stronger cardio system it would be able to feed your legs more fuel and oxygen and not cause you to go anaerobic.
    I was a fast runner at one point, and got into racing MTB, it wasn’t until I increased my intensity and started doing hard hill climbs and put on some leg muscle did my riding improve greatly, also my running improved a lot as well.
    We use to do intervals running etc, but nothing seemed to push me to the puke level like charging up steep hills on my bike, esp. when my legs got stronger and I could ride harder longer, this I think really forced my heart to catch up in strength as well.
  2. Strength training doesn’t help cycling it’s not specific
    If you train wrong that could be possible, but I’ve seen with my very own eyes what a huge improvement strength can make in cycling and other sports. I’m a strong advocate of strength training for cycling, and almost any sport, and in life in general. I also believe in doing cardiovascular training as well of course. I think for athletes with a lot of natural strength, it might be possible that they don’t get as much benfit. But I am very suspcious of any serious athletic coach that doesn’t recommend at least some strength training for their athletes. I’m not alone on this either, there’s a reason why Lance’s coach has him hitting the weights in the winter.
  3. You can still push your heart muscle hard by doing full body aerobic sports, even if your leg muscles are failing to push you to the limit in cycling.
    This I could see as a valid point and perhaps why two of the greatest cyclists Eddie Merckx and Greg Lemond both did cross country skiining in the offseason.
    But for many cyclists, they don’t do much cross training, so I question their ability to train their cardio system hard enough if they’re riding with legs that aren’t very strong.

These are all my crazy theories, but I just wanted to write them down so I dont’ forget what I’m thinking.

How many training miles should you target in your cycling training plan?

I think mileage is a poor measuring tool in training it can be misleading and cause you to be either be over-trained or under-trained easily, and probably not much faster of a rider either. A mile is not always a mile, ask your body it will tell you. If you ride down by the ocean and it’s flat and you have a tailwind the whole ride and end up doing 100 miles, and the next day you ride 10 miles of endless hill climbs the milage was very different but you feel like it was just about the same amount of effort. I’m training my body not my bike, so instead of measuring the mileage that my bike endured, I measure what training load my body endured. I look at

  1. Training sessesion time
  2. Average watts
  3. Average heart rate
  4. Perceived rate of exertion
  5. And if you have a power meter, using tools like training peaks software you can measure training load even more accuarately.

There are other things also to think about as well when planning your training load like

  1. How much time does your target event take at your projected race pace?
  2. What type of intensities occur during this length of event, what energy systems will you be using?
  3. What type of event is it, what riding positions will you be in?
  4. What are your strengths and weaknesses, how is your body built, dominate muscle fiber type, cardio strength etc.?
  5. What specific events and goals are you targeting with your training?
  6. How well does your body respond to certain types of training?
  7. What types of training methods do you like doing, and can tolerate doing all winter?
  8. What types of training in the past have you found helped you most? I think this is a key thing that is not mentioned often. I think for some people they’ll find their bodies react differently then others to different types of training. So it’s important to keep training logs, and also measure improvements in fitness to gauge which training methods worked best for you as an individual, what types of loads, duration, intensity, frequency helped you most?

The main thing to keep in mind I think when planning your training load is to measure your duration and intensity, and not to worry about mileage, and to train specific to your own body’s needs to reach your targeted goal’s length and type of intensity.

The thing I find interesting too is that by training your weaknesses you often end up being a better all around rider as well and should be able to do well in a wider range of event durations and intensities. It’s been shown that training your weaknesses can also make your strengths even stronger. The track sprinter, who also does longer rides when training ends up making improvements to his sprints as well, the iron man that lifts weights and does on bike strength training, achieves a higher average sustained pace and experiences less muscular failure and ends up having more endurance because of his new found strength. But of course you would spend most your training time on building up the energy systems that are mostly used for your event. And if your event requires a balance of systems like road racing, then you should be training each system, and in particular the systems that are weakest that would give you the highest pay off if you improved it.

For my own training my goals this season are to build up as much strength and power as humanly possible as I discovered that strength and power are my body’s main weakness and also the thing that I would need to improve the most to be competitive at 1-2hr long events. I naturally have above average endurance, but below average strength. My target events for this season are almost all around 1-3hrs long, and the faster I can ride the shorter the duration of the event will be, the 3hr event will be closer to 2 hrs. if I can make a big improvement to my average power output, even more reason for me to train to get faster, then I can be home in time for lunch this year at my favorite local triathlon ahhaa. I love being fast, even if it’s only for part of group ride or a race, I’m most excited at the idea of riding very fast even if it’s only for a few miles. I want to be able to go 30MPH for a mile or two at least and be able to sustain 25mph for at least 5 miles, with plans to continue to increase my top end speed and the length of time I can sustain 25MPH+. I also want to focus this season more on road cycling and crits then triathlons, but as I mature in my training I will be aiming at ultimately at longer and longer events hopefully eventually getting to where I’m doing ironman races and being competitive. But we’ll see, I’m playing it by ear, as I haven’t trained and raced long enough to know what events I’d be best suited for, and which ones I like the most.

So taking into account my goals, my target event duration and types of events and the energy systems they call on. This season and probably next season I’m focused mostly on becoming fast, so I have something more then just mediocre speeds to endure.  For me to be fast I need more strength and power not more endurance, esp. since I have no problem with endurance. So my current training consists of mostly improving my maximum strength, speed, and power, and also stretching that new found speed and strength out to longer and longer times. So far I’m seeing very good progress, because I’m focusing on my weakness, and because this is the first real off-season that I’ve trained for cycling, I’m sure next winter I will be seeing a 100+watt threshold improvement in a couple months of training like I did this winter. Probably I will see a 20-30w improvement in the next year as from what I read that is about the average rate of improvement for most people in the off-season.

I think after a couple seasons of focusing on being as fast as possible for short durations I should start seeing my rate of improvement decline as I start to get closer to my genetic strength potential, then I will probably get more out of my training by focusing on extending the amount of time I can sustain a fast pace.