Thursday, February 19, 2009

Training - Analyzing My Jump

Yesterday I decided I'd work on my California tan. Although my throat and head weren't feeling great, they felt okay. I (thought I) felt good enough to go out in short sleeves and shorts, and wore a wind vest to keep my torso/core warm. I found out that although warm outside when sunny, the cold wind really ate away at my heat reserves. My throat started feeling sore, I felt some pressure in my head, and I found myself feeling chilly (and stupidly unprepared) within 1.5 hours of starting out.

So, after a nice chat with the missus (we missed our daily call yesterday so we made up for it today, me leaning against the guardrail next to the sunny PCH, she bundled up in snowy Connecticut), I decided to cut my ride short and go home. I turned around at the next convenient area.

That's when the wind really hit me.

It was killer, a steady 20 mph cross-headwind. I rode in the drops for a bit, it was that bad.

I think I rode the whole PCH section of the ride in the small ring, and I found myself in lower and lower gears. It helped when I ate a FiberOne bar I'd brought along, although getting the wrapper back into my pocket (under the vest) almost caused me to ride off the road.

I headed inland, the wind much kinder. My legs didn't care - I couldn't go hard at all. I crawled up and down some hills. Some guy in a full kit, probably a commuter based on his messenger bag, positively blew by me on a particular grade. He quickly disappeared out of sight. I watched him and thought, boy, I'm slow.

A few minutes later I came up to a light. Mister Kit was there. The light turned green and we started off. Since I didn't want to act like a total dweeb, I stayed respectfully behind him. He ramped it up and disappeared again.

A couple minutes later I came up to a light, and would you believe it, Mister Kit was there again. I felt kind of bad, like he may mistake me for a cycling stalker or something. I went super easy when the light turned green, but then so did he. After realizing I wasn't going to try and pass him back, he took off again.

A couple minutes later.. Yep, I rolled up to him again. I didn't even see him until I was a few cars away from him. He again went easy, I went easier, then he went a bit harder.

Finally I watched him roll through an intersection as the light turned yellow. I stopped and hoped that I wouldn't catch him again. Of course he's probably posted on his blog about Mister Stalker who kept catching him and following him.

I felt relieved because I'd been waiting for a particular stretch of road to do an experiment. A sprinting experiment, the best kind.

On the forums someone asked for some sprinting advice, and after reading a bunch of responses, I realized I had no clue about my optimal jump cadence. I guessed it was about 90 or 95 rpms, but I really didn't know. I did know that yesterday I did a little jump and had two almost equal power peaks, both at about 95 rpms. My sprint graph resembles a ski jump - starts high, then plummets as time goes by. One of my goals is to try and extend the top of the slope so that I spend more time at the high power area.

So today I decided I'd jump at 95-ish rpm, no matter what gear it was, and shift as soon as I thought I could shift and end up at 95-ish rpm again.

Luckily Mister Kit was gone - it'd have looked really amateurish to go sprinting past him and then blow up.

I rolled down my leadout hill, braking, keeping my speed low enough so I could jump in a relatively low gear. I gripped the drops, set my body, and got ready to do a killer massive jump.

As I started up the sprint hill I checked my cadence - 80. I shifted down once more. 88. I shifted down again. I saw 90-something and BAM I was going.

I did two downstrokes with one foot before I instinctively slammed the shifter, doing another hard surge. I think three downstrokes went by before I shifted again, and I did another surge.

That's about when my head started really pounding, the lactic acid suddenly overflowed, and my legs started to wither. I hoped that maybe I had another surge in my legs, shifted up once more, and essentially fell flat on my face.

I sat down, put the bike in the 39x21, and tried to catch my breath.

When I got home I checked what happened in that little effort.

First off, it took all of 11 seconds to totally and completely fry me for the next few minutes.

Second, somehow I managed to keep my cadence such that each time I surged, I did so at 95 rpm or so. I accelerated up to about 100-105 rpms in each gear, shifted, and found myself at about 95 rpms. I shifted one gear at a time, one tooth at a time. I'm pretty sure I started in the (53 x) 15T, ending in the 12T.

Third, each of the efforts were within 100 watts of each other. Well, each of the first three. The fourth dropped off by about 25%, putting in the realm of "not really a sprint". My speed didn't drop but I wasn't going to accelerate anymore.

Fourth, my ski slope graph suddenly had a little area for skiiers to wait in line. A jagged area, yes, but an area.

So what's this mean to you?

Analyze your jump, analyze your sprint. If you know what your legs like to do, you can try and adjust the situation so that your legs are happy.

Figure out at which rpm you jump best. The jump is a vicious pedal stroke, meant to do everything possible to accelerate the bike forward. If your pedal stroke was a car, your jump would be a Top Fuel Dragster. If you don't have a downloadable cyclocomputer (SRM, PowerTap, Garmin, etc), do jumps from different rpms and figure out at which rpms you felt good. The original forum post person did just that in an effort to narrow her cadence range for her jump, but she due to limitations in equipment she simply noted rpms and how it felt for each rpm range.

Figure out at which rpm you can sustain your 5 second or 10 second power. This is different from your jump - it's a smoother, sustainable effort. To use the car analogy, your sprint is more like a Land Speed car. I didn't do any experimenting with that today because there was no way I would be able to sustain any kind of effort. However, since that power is much lower than the jump power, I'm guessing that the rpm will be a bit higher than the jump rpm.

Write things down (which is a good thing in general). Make notes after rides (or even during them if you're on a trainer). Jot down things like gearing (jump gear and ending gear), cadence (if you can get that), and ending speed (look down just after you finished sprinting). Ultimately you can calculate your cadence based on speed and gearing. If you have a cyclocomputer that records max cadence (as well as speed), you can reset the computer before each sprint. This way you'll have the data for that short period of time.

Remember trainers don't allow the bike to rock (with a couple exceptions) so your power and your form will be a bit mutated.

It's only mid-February, but we're approaching the race season fast. Working on your sprint in a logical, calculated way can pay dividends when the warmer weather finally hits.

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