Sudden faster but don't know why

Since September my average cycling speed has picked up measurably. Despite a more challenging route, speed records have fallen one after another after another. I'm not sure why, and I'd like to get some opinions on it.

Why? So that I can make sure to keep doing whatever it is I changed.

Here is my data from since I started riding a bit over 2 years ago:


(Notice that sudden up curve? That's just since September 26th).

What has not changed: Gear. Same cheap clothes, same 35lb hybrid bike. Tires changed, but probably too long ago to be a factor.

What has changed:

1. New Route
I have changed work locations slightly (by like 2 miles) and thus I'm riding a different route. The route features around 200 feet of additional elevation gained, however, and I can tell you that it is definitely a more challenging route.

This might make me stronger, yes? Maybe, but wouldn't that equate to similar speeds on the new route and only faster on the old route? Instead this new route with more hills has me going measurably faster. To make matters worse, I can't really do the old route for comparison.

2. Seat Position
My seat was all the way back. Adjusted for the correct height (heels-on-pedals method), after a hard ride I felt it mostly where my hamstrings met my glutes. Just before the move, I moved it forward and re-adjusted the height (took a few tries). This has left me perhaps with a more efficient application of power on the cranks, but also more upright in the wind. I'd think that would be a wash, but maybe not.

3. Core Exercises
I have a bad low back, which generally stems from the mid body X being off kilter. Strong quads and lower back muscles, weak abs and glutes. So I started doing planks and back bridges to strengthen these lacking muscle groups. I have noticed that I am much straighter now (when my back is bad I am crooked in the hip area, which is a strange thing to see and difficult to describe).

4. No fellow riders
It's just me and my ego, and my ego is a loud-mouthed SOB. Maybe I already had this in me and I just didn't let it out. Seems unlikely, though.

Googling this doesn't really help much.

Opinions?

 

The likely answer is the combination of better conditioning and better fit on the bike. Certainly better core strength will be a contributing factor. Out of curiosity, what is the R2 for the curve fit you have shown?

 

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Some of it is prejudiced by the really down days on the chart (below 13) which is usually where my back was out of whack, and the higher numbers where I've done fitness testing on a fairly flat course (so maybe 200-250 feet vs. the 425-500 I'm doing now).

 

Less stops? Different measurement method?

Prevailing winds, is the new route in a different direction, or perhaps it is more sheltered.

Shorter days, I find myself speeding up as the sun begins to set to get in before dark.

Or maybe you are being misled by the curve you fit. Put on the blinders and it looks like you preformance was decreasing from Jun to Sep.

 

I see several possible explanations:
- Different wind condition
- Better asphalt road (that plays a lot)
- Global faster route (less stops, less curves, etc.)
- Better training (even if you don't feel it)
- Good physical condition (more rest, etc.)
- The fit curve may induce wrong conclusions. If you draw it again in 6 month or in a year, that sudden up curve will probably disappear.

Manu

 

Improvement could be due to factors which you don't list such as weight loss.

From the factors which you do list, the improvement in your back from the core exercise routine looks to be a likely explanation.
Manu3172 list is worth considering.

or you could just accept the improvement and use it to improve further!

 

There are less stops, true. Mostly right turns as well, but my old route the turns generally didn't result in stops. That's a hard one to measure.
Prevailing winds have been all over the place, but actually this route is less sheltered than my old one. More open fields, where my old routes tended to be all in woods and housing developments.
I ride at lunch, so length of day isn't so much of a factor.

I plotted the curve because I noticed the consistently higher speeds. If you look at the chart even without the trendline you can see the sudden uptick in speed. My "slow" days were suddenly as fast as my fast days from before. I was consistently dropping speed records on my good days.

June to September I had some back issues and took my time building back up. The big change came on September 26th, which is my first day starting the new route.

All good observations, though.

 

Wind has been all over the place, but I'm generally more exposed on this route.
Asphalt is worse, especially this one section...ugh.
There are fewer stops and mostly right turns now. I'll have to think about that one.
It was too abrupt, I think, and it's a tougher route, so I don't think it was training. Unless generally improvements are in fits and starts and not rather than gradually, which may be true.
More rest is a possibility. That's a good thought.
The fit is showing me what I kind of already was seeing in my general speeds. I generated it as a visual aid.

 

Sadly, no weight loss. Holding fast at 218.

It was a nice thought though.

 

Thanks for the response guys. There were definitely some good insights, and I thank you for your encouragement.

Unfortunately I think you've fairly convinced me that the route has something to do with it. With only 7 turns, 6 of which are right hand turns, I rarely have to stop anymore. While I didn't always before, it was a bit more awkward.

I also ran a different route today, and while I was a bit faster, overall it led me to believe that my ego is mostly to blame here. I think I was basically turning myself inside out every single ride now that I ride solo (looking back, the fact that walking up stairs after a 45 minute ride was difficult ought to have been a clue). I think the seat position did help me use more leg muscles then before (I think before I was putting too much stress on my hamstrings), but not that much. I don't think the core contributed other than to let me over-do it without my back going out, so an indirect benefit.