# Bike fit and Power output



## Srode (Aug 19, 2012)

I got a bike fit done this week and the next few times out I noticed a big jump in 15-30 second power output, like 7%. 2-5 minute power up maybe 3% and 20 minute power up 2%. The fit raised my saddle a bit over an inch, kept the same reach (moved the seat forward to get the same reach) and raised the bars plus minor adjustment to left cleat and brake lever. Is it typical to see that much more difference in the shorter duration power and less in the longer after a fit?


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## Kerry Irons (Feb 25, 2002)

Srode said:


> I got a bike fit done this week and the next few times out I noticed a big jump in 15-30 second power output, like 7%. 2-5 minute power up maybe 3% and 20 minute power up 2%. The fit raised my saddle a bit over an inch, kept the same reach (moved the seat forward to get the same reach) and raised the bars plus minor adjustment to left cleat and brake lever. Is it typical to see that much more difference in the shorter duration power and less in the longer after a fit?


An inch is a LOT of change in position so assuming your previous position had you really sitting way too low then a big improvement certainly is possible. That said, an inch is a LOT of change in one go and you need to be alert for injuries resulting from a too-rapid change in position. Typical recommendation is a few mm at a time as you work toward the proposed desired position.


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## woodys737 (Dec 31, 2005)

I don't think there is an answer to your question. It probably depends on how on or off your fit was prior to the changes and extremely individual. But as Kerry states, 2.5cm/1 inch is a huge change if you try and move all at one time. Many advocate 3-5mm change, then adapt, change another 3-5mm, adapt again etc...Please consider moving back to your original position and incrementally moving towards the new fit over time to avoid injury.

25-35 degree knee angle is currently accepted (sorry FTR and Steve Hogg) as a general rule of thumb for seat height to generate best power while avoiding injury. Very complex subject and based on the unique problems and characteristics of each individual. Steve Hogg recommends a slightly different approach which resulted in very similar results for me personally as compared to the Lemond method. But that's just me. Everyone is different and fit can/will change given many factors.

Being balanced and comfortable on the bike is very important imho (thank you Steve Hogg). Making small changes to fit and give time to adapt is also very important.


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## Srode (Aug 19, 2012)

I've put about 90 miles over 3 rides on it since the change with a TSS of around 400 - no pains, but making this change in several smaller steps makes sense. I can lower it now that I know where the more optimal position is and go up in steps, but how much time to adapt between the changes? I normally ride 100-150 miles / week, mostly fairly hard riding (for me anyway). 

What is very noticeable is before the fit I could feel my feet/legs hitting the bottom of the pedal stroke quite abruptly and now they float around the circle more smoothly. My left leg is a tad shorter than right so that is the side that was used for the leg angle. He didn't think there was enough difference to warrant shimming the cleats though.


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## woodys737 (Dec 31, 2005)

IIRC Steve Hogg recommends several weeks riding at less than maximal intensity. I don't recall his exact recommendation. Heading out the door for work...


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## Kerry Irons (Feb 25, 2002)

Srode said:


> I've put about 90 miles over 3 rides on it since the change with a TSS of around 400 - no pains, but making this change in several smaller steps makes sense. I can lower it now that I know where the more optimal position is and go up in steps, but how much time to adapt between the changes? I normally ride 100-150 miles / week, mostly fairly hard riding (for me anyway).
> 
> What is very noticeable is before the fit I could feel my feet/legs hitting the bottom of the pedal stroke quite abruptly and now they float around the circle more smoothly. My left leg is a tad shorter than right so that is the side that was used for the leg angle. He didn't think there was enough difference to warrant shimming the cleats though.


No hard and fast rule because riding intensity, your own adaptability, and the kind of rides (flats, hills, steady pace, sprints) all come into play. At your weekly mileage I would say at least a week between changes.


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## Cyclin Dan (Sep 24, 2011)

Kerry Irons said:


> No hard and fast rule because riding intensity, your own adaptability, and the kind of rides (flats, hills, steady pace, sprints) all come into play. At your weekly mileage I would say at least a week between changes.


I got a fit that changed my saddle height 3.25 inches and I did it all in one go. 

Man, my saddle was way low!


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## davez26 (Nov 15, 2010)

I've been riding over 30 years. My fit raised the saddle about 3mm, back 7mm, shimmed my shoes in 3*, shortened stem 10mm, and swapped the seat. 
I've ridden a few times and picked up 1 mph over a 60 mile ride, and...my back pain went away. 
I'm not sure if it's from fit or psychosymatic, but I know I sure feel more powerful.


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## Alex_Simmons/RST (Jan 12, 2008)

woodys737 said:


> IIRC Steve Hogg recommends several weeks riding at less than maximal intensity. I don't recall his exact recommendation. Heading out the door for work...


The bigger than change, the longer you need for an adaptation period. It might be days to weeks.

When a client has a fit change, I use a rough rule of thumb for adaptation period for the maximum change to effective reach (either seat to pedal, or seat to hand grips): 1-2 days of steady riding (avoid maximal efforts) per mm of change, provided the new position makes positional sense.


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## Poncharelli (May 7, 2006)

Agree with everyone regarding fit adaptation time. That's why I typically get a fit during the off season, so when I start riding again there's all sorts of adaptations happening, so I typically go straight into the fit with no adjustment period. 

I've had several fits over the past decade: Specialized BG, Wobble Naught, Retul, and a couple of individual people who were recommended. 

Specialized BG = lower saddle, not so set back.
Wobble Naught = higher saddle (~1.5cm), 1cm more setback than BG. 
Retul = slightly higher than wobble naught (.5cm), and more set back than WN (.5cm)

I liked the Retul but it's really expensive (had the fit February 2013). With the sensors they use they can get a lot more feedback per unit time while the fit is dynamic. There can be some error with sensor placement but it seems that it difficult to screw up. 

Wobble Naught and some other individual fitters do cleat placement where Retul did not. But Retul determined that my knees didn't kickout enough (when viewed from front) to warrant cleat changes or shims, etc. 

I'd have to say that Power changes for me are more a function of training time than fit. It takes me a while to adapts to fits as well. My goal is less pain rather than more power. The retul fit has been good so far in regards to lower back and IT band problems. 

Here's one of my mates doing a review on the fit. I'm not sure if he stuck with it:
Biker?s Edge Fit

The cockpit length is rather agressive. On my fit, I wound up lifting my handlebars a bit and lowering it slowly. Still not down where Retul wants me.


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## spade2you (May 12, 2009)

woodys737 said:


> IIRC Steve Hogg recommends several weeks riding at less than maximal intensity. I don't recall his exact recommendation. Heading out the door for work...


Whenever I made changes, I'd test stuff in 10 mile increments. 

I agree that you can lose significant power with a bad fit. It's so much easier to train longer when the bike fits and there's no unnecessary pain.


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## Undecided (Apr 2, 2007)

Srode said:


> I've put about 90 miles over 3 rides on it since the change with a TSS of around 400


Off topic, but are you confident your threshold is set correctly? Not that it's impossible, but I'm having trouble imagining how I would do 400 TSS in 90 miles.


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## 32and3cross (Feb 28, 2005)

Depends on the person, When I had my first fit Eddie B raised my saddle about 2 inches and sent me off to climb Mt Palomar, now my saddle was clearly too low but it didn't seem to hurt me.


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## Cableguy (Jun 6, 2010)

Two pro fitters recommended around the same seat height for me. For a long while now I've been running about 2cm *lower* than their recommendation. Both my power and comfort improved. I am the best fitter on the planet... for myself


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## Srode (Aug 19, 2012)

Undecided said:


> Off topic, but are you confident your threshold is set correctly? Not that it's impossible, but I'm having trouble imagining how I would do 400 TSS in 90 miles.


I think it's accurate, I just did a 20 minute test. I've only been riding a year now, so you are probably have a higher FTP and so would have a lower TSS for the same miles. My 20 minute power is only 251 watts. Just went back and looked at my Golden Cheetah data, TSS for the 3 days was 142, 144, 149 covering 32, 26, and 32 miles respectively. Total elevation change about 3000 feet. Yours would be obviously proportionately lower TSS for higher FTP. 

I know, I have lots of work to do yet, but I'm older so it's taking some time to get the gains.


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## Undecided (Apr 2, 2007)

What was the duration of those rides? I know this is not what you were asking about, and it's none of my business (and I'm not trying to be discouraging, I just want you to be using your training tools as you intend and expect).


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## Srode (Aug 19, 2012)

Undecided said:


> What was the duration of those rides? I know this is not what you were asking about, and it's none of my business (and I'm not trying to be discouraging, I just want you to be using your training tools as you intend and expect).


Hey, I appreciate all the help I can get - if I'm using the data incorrectly for training I want to fix it. Here's data from GC for those 3 rides. Ignore HR over 185, those are over due to a flapping jersey most likely. Let me know what you think / if you see anything odd. The most recent 20 minute power test is in the 3rd ride. 

*Ride 1*
*Totals*
Duration:	2:16:10
Time Riding:	2:09:07
Distance (miles):	31.68
Work (kJ):	1113
Elevation Gain (feet):	1237

*Averages*
Speed (mph):	14.7
Power (watts):	144
Heart Rate (bpm):	131
Cadence (rpm):	75

*Maximums*
Speed (mph):	33.1
Power (watts):	635
Heartrate (bpm):	197
Cadence (rpm):	110
*
Metrics**

xPower (watts):	177
Relative Intensity:	0.743
BikeScore™:	125

Aerobic Decoupling (%):	-7.90
Heartrate (bpm):	197
Power (watts):	635
60 min Peak Power HR (bpm):	138
5 min Peak Power (watts):	274
Distance (miles):	31.68
20 min Peak Power (watts):	178
1 min Peak Power (watts):	395
30 sec Peak Power (watts):	468
5 min Peak Power HR (bpm):	171
TSS:	142
Left/Right Balance (%):	0.0
Watts Per Kilogram (wpk):	1.7
10 min Peak Power (watts):	205

*Power Zones*
Zone	Description	Low (watts)	High (watts)	Time %
Z1	Active Recovery	0 130 57:34 45
Z2	Endurance	130 178 21:49 17
Z3	Tempo	178 214 14:17 11
Z4	Threshold	214 249 11:16 9
Z5	VO2Max	249 285 09:44 8
Z6	Anaerobic	285 357 10:11 8
Z7	Neuromuscular	357 MAX 04:16 3


*Ride 2*

*Totals*
Duration:	1:48:51
Time Riding:	1:45:12
Distance (miles):	26.03
Work (kJ):	881
Elevation Gain (feet):	1047

*Averages*
Speed (mph):	14.8
Power (watts):	140
Heart Rate (bpm):	126
Cadence (rpm):	71
Temp (F):	71.1

*Maximums*
Speed (mph):	38.9
Power (watts):	914
Heartrate (bpm):	179
Cadence (rpm):	109

*Metrics**
xPower (watts):	185
Relative Intensity:	0.779
BikeScore™:	110
Aerobic Decoupling (%):	9.40
Heartrate (bpm):	179
Power (watts):	914
5 min Peak Power (watts):	275
Distance (miles):	26.03
20 min Peak Power (watts):	185
1 min Peak Power (watts):	388
30 sec Peak Power (watts):	650
5 min Peak Power HR (bpm):	166
TSS:	144
Watts Per Kilogram (wpk):	1.7
10 min Peak Power (watts):	221

*Power Zones*
Zone	Description	Low (watts)	High (watts)	Time %
Z1	Active Recovery	0 130 50:24 48
Z2	Endurance 130 178 18:19 17
Z3	Tempo 178 214 11:37 11
Z4	Threshold 214 249 07:50 7
Z5	VO2Max 249 285 05:52 6
Z6	Anaerobic 285 357 06:18 6
Z7	Neuromuscular	357 MAX 04:52 5


*Ride 3*

*Totals*
Duration:	1:53:54
Time Riding:	1:51:03
Distance (miles):	31.38
Work (kJ):	1147
Elevation Gain (feet):	954

*Averages*
Speed (mph):	17.0
Power (watts):	172
Heart Rate (bpm):	140
Cadence (rpm):	75
Temp (F):	73.7

*Maximums*
Speed (mph):	36.4
Power (watts):	791
Heartrate (bpm):	219
Cadence (rpm):	109


*Metrics**
xPower (watts):	201
Relative Intensity:	0.846
BikeScore™:	136
Aerobic Decoupling (%):	3.83
Heartrate (bpm):	219
Power (watts):	791
60 min Peak Power HR (bpm):	144
5 min Peak Power (watts):	260
Distance (miles):	31.38
20 min Peak Power (watts):	251
1 min Peak Power (watts):	388
30 sec Peak Power (watts):	421
5 min Peak Power HR (bpm):	170
TSS:	149
Watts Per Kilogram (wpk):	2.1
10 min Peak Power (watts):	255

*
Power Zones*
Zone	Description	Low (watts)	High (watts) Time	%
Z1	Active Recovery	0 130 37:34	34
Z2	Endurance 130 178 23:40	21
Z3	Tempo 178 214 13:44	12
Z4	Threshold 214 249 10:09	9
Z5	VO2Max 249 285 09:25	8
Z6	Anaerobic 285 357 10:08	9
Z7	Neuromuscular 357 MAX 06:23	6


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