Saturday, January 28, 2012

Removing the variables.

I had a conversation with an athlete recently regarding removing the variables in training. Swimming is probably the easiest. Very few things change. My local pool does not change in length (to the best of my knowledge), the viscosity of the water does not change very often, the temperature of the water is consistent and I wear the same swimming attire. Therefore, the only thing that changes is me (my stroke, my intensity, my motivation). Swimming 100’s on the 45 should be the same day in and day out. If I improve on my times then I am working harder or I am more efficient. Easy stuff.


Next up is the run. You have different routes, different contraptions (treadmills), different equipment and different conditions. Sometimes I run up hill, sometimes I run downhill, there can be wind from any direction and the surface can be soft, hard or even muddy. However, if I run the same route in the same conditions then I have removed some of these variables. I also have access to an indoor track. This removes many of those variables. The track is flat, the temperature is consistent and the length never changes. I can run this track at a predetermined pace or heart rate. I can then compare these numbers to past sessions to see if I am improving. The variables have been reduces. There are a few more variables in running than swimming but they are easy to minimize.

The bike is a whole other matter. You have the temperature, wind, elevation change, surface conditions, aerodynamic position, drafting, tire inflation, tire resistance and a host of other variables. I can be riding the bike at a very hard effort and average 18 MPH or be riding easy and averaging 22 MPH – it depends on the ride. Even when I do my marked and known distance time trial, the variables are just too many. I have completed one of these time trials and thought I had ridden my best ever only to come in a few seconds slower than my best. A power meter can definitely help to mitigate these variables but this is an expensive and potentially complex piece of equipment. Not everyone wants to make that investment in time or money.

A trainer can also be used to help eliminate some of the variables but only if several steps are taken. First, the trainer takes out the incline and decline, eliminates the wind and you can control the climate. But there are still variables, the next being the tire contact pressure and tire inflations. When I first mount my bike on the trainer, I reduce the pressure in the tire. I mount the bike and crank the tire resistance unit a certain number of revolutions. Your trainer will vary but try to get in the habit of always tightening down the resistance unit the same each time. Next, I inflate the tire to the same PSI each time. The exact amount does not matter as long as you are consistent, anywhere between 100 – 120 PSI should be sufficient.

Next, when I ride the trainer I try to keep the warm up the same. On many trainers, the resistance will change as the unit warms up. By performing the same warm up, each time, the trainer’s resistance should be the same by the time you reach your working set.

That takes care of the friction on the rear wheel. With these variables eliminated, you can be sure that the amount of effort you are putting out will be the same each time you ride the trainer. You can now use your speed and cadence to repeat trainer sessions that should provide the same workload.

Through trial and error and performing benchmarks, you can define your intensity zones. You can now repeat workouts with the same workload. For example, if you performed a 20-minute effort at xx MPH and at XX cadence in the same gear, you can be certain that when you repeat this workout you will be producing the same about of work. Over time, you will then be able to adjust your output by increasing cadence or speed.


Kirk said...

I never thought about all the variables until you mentioned them. You are right. The swim can't, or usually isn't done on a trainer. So its the same every time. But the bike is a tough one. Especially when you switch, like I do, between a real bike, a trainer and a spin bike. The only consistent gauge I have there is my heart rate. Good post!