Like a rollercoaster baby, baby, yeah I wanna ride

To stir some debate on the distribution of effort in a TT (or a solo break!), I present the following table, compiled from the tools on Analyticcycling.com. Using the default 75 kg rider/bike, as well as the defaults for just about everything else, I plotted the power requirements for various speeds on a 3% grade, flat grade and 3% downhill grade. The idea is to examine how one might best attack a rolling course.

We are not machines, so for us to put out power, things are not as simple as pouring in fuel. I leave it to you to decide whether trying to keep power output constant is beneficial and/or desirable. Personally I do not believe that it is. Of course a number of factors, such as the length of the effort come into play. For these same reasons, I feel that the studies on pedaling efficiency/cadence cited on pez were somewhat flawed. The test durations are too short to be have much meaning to someone who does races lasting hours, and lots of other things warrant consideration. Muscle fatigue manifests itself in a number of different ways that no test could replicate, and thus limits ones abilities to do certain things, such as sprint or accelerate on a hill to stay with the group. Having fresh muscles when you need them is more critical than having a lower hearbeat/watt number. My thoughts on this could ramble forever, so, realizing that what I have written is in no way clear, I will move on with the simple hope that you picked up on the kinds of things I am trying to consider.

Getting back to our table, my point is much more direct: you are better off using your power just before the crest of a hill than anywhere else. Notice that when flying down a gentle grade at 16m/s (57.6 kph), if our example rider wants to increase their speed by 1 m/s (3.6 kph) the power requirement jumps from 322 watts to 428 watts (+106 watts). However, if they are on the 3% upslope, and only traveling 8m/s (28.8 kph), the same increase in speed is only going to cost them 58 watts. This is the result of fundamental physics where the fluid drag increases with the square of velocity.

Grade				3.00%	0.00%	-3.00%
m/s	kph	wind kg/ms2	wind gmf	watts	watts	watts
20	72.0	61.30	6255	1726	1285	844
19	68.4	55.30	5645	1526	1107	688
18	64.8	49.70	5067	1344	947	550
17	61.2	44.30	4519	1178	803	428
16	57.6	39.20	4003	1028	675	322
15	54.0	34.50	3519	892	561	230
14	50.4	30.00	3065	771	462	153
13	46.8	25.90	2643	662	375	88
12	43.2	22.10	2252	565	300	35
11	39.6	18.50	1892	479	236	0
10	36.0	15.30	1561	403	183	0
9	32.4	12.40	1261	337	138	0
8	28.8	9.80	1000	279	102	0
7	25.2	7.50	766	228	73	0
6	21.6	5.50	563	183	51	0
5	18.0	3.80	391	144	34	0

I have heard after many TTs where riders talked of being in their 12 cog all the way down such and such a stretch of the course. That is fine, but if your output is badly compromised on a subsequent rise, then I think you wasted some effort. Powering over the crests and getting up to speed on the downside is critical, but trying to squeeze a few kph more out of the fast parts of the course can be a misuse of valuable energy. You are better off taking some recovery and saving your muscles for the sections of the course where you are not pushing so much air mass out of the way.

The next piece of this is how does this affect your position? My practice has been to "stretch out" and slide forward, get my arms close together, hands to the foremost portion of the aerobars, and pull the knees in on the fastest (downslope) portions of a course. I know I can't make as much power this way, but at over 50 kph, being aero is most beneficial. On the flip side, if I am coming to a grade where I need all the power I can get, I allow myself to slide back a bit, and "choke up" on the aerobars, maybe squaring my shoulders a little to facilitate better breathing. On a rise at 25 kph, being aero is not nearly as critical.

Throttling the power/energy judiciously to maintain momentum, lessen the pain of the rises, and exploit the downslopes is where I think I make up time on riders who could probably torch me in any lab test. I use everything at my disposal, every windbreak, the crown of the road, etc to my advantage if I see one. When and where to get out of the aerobars, or out of the saddle is always a dilemna. You never feel like you get it perfect, but if you hit one just right, the mental boost you get from flying over a crest is surely worth a few seconds. That's the TT world according to me. Don't go as hard as you can, go as fast as you can! :o)