I just had a performance test done a few weeks back and discovered that my LT on the bike occurs much earlier (as a percentage of my MHR, and VO2 max) on the bike as compared with the run. My LT also occured at a pretty low wattage (a measly 150 Watts).
From what I’ve read, I can probably do a lot to improve my race performance if I raise my LT (as a percentage of my MHR) and improve my power at LT. Based on this, I’m looking for any suggestions on workouts to improve my LT and power.
To give you a sense of my fitness- I did my first IM last year (IM Canada) and finished in 10:16 with a 5:26 bike split.
All those suggestions make a lot of sense. I’ll definitely give those workouts a try. I’ve got one more question, if that’s OK…do you have a book or anything that you’d recommend I read on this subject?
Francois is correct, there is no way you did 5:26 at IMC with an LT power of 150.
For reference, my LT power (average power in a 30’ TT) is around 210-220. Extrapolating from my Lubbock 1/2 IM results I expect that I would get a 6 hr bike split at IM FL.
I agree with Francois that your LT seems to have been highly underestimated. My LT last year was 245 Watts (I’m 160 lb) and I went 5’26’’ on the bike @IMC (9’53’’ total). Your weight will influence things. It’s often good to look at your power to weight ratio (ie if your 100 lb a 150 watt LT much better than if your 250 lbs).
My coach tests and prescribes bike workouts by wattage. His approach to increasing LT is to ride just above LT for 3-5’, recover just below for 3-5’ and repeat to failure. Failure should occur between 20 and 40’. Eg last year I’d do 5’ at 250 Watts and then 5’ at 230 Watts. These are very tough workouts (for me at least). They also require that you have a power measurement or control device (ie computrainer, SRM or power tap). You can subsitute HR for power as your intensity measure but it is a lot less reliable and it is only valid during the first 5-10’ as your HR will drift upwards after that.
A highly effective workout which I learned from some of the very smart people (exercise physiologists, etc.) that post on the Wattage list is 2 x 20 minutes (with about 5 minutes rest between) at 95-105% of your LT power, defined as the average power you can hold during a 40k time trial (approx. 60 minute). I do this session two times a week using my Computrainer in ergometer mode, increasing the wattage by 5 watts every 2 weeks.
I’ve seen substantial gains in LT power, as well as my steady state power output in the endurance and tempo zones, since implementing this regimen.
More info than you ever wanted to read about this kind of training can be found in the archives of the Wattage list on Topica.
I have seen a study which indicated that 4 mmol/L may not be an appropriate definition of LT for all people. In the study subjects rode a 1hr time trial while there blood lactate was monitored. The result was that some of the subjects were able to tolerate a higher than the 4 mmol/L level.
How did your measured LT correspond with other variables such as ventilatory threshold, RPE, and HR during time trial efforts? It appears possible that 4 mmol/L is not physiologically correct for you.
Excellent point Richard.
I was kind of wondering about that myself.
I think my weakness is that although I have a high tolerance for lactic acid, I produce lactic acid at very low levels of exertion.
Here are my reasons for saying this:
In the performance test, my RPE and HR at LT felt very low. I hit 4 mmol around 145 bpm. and RPE about 13 or 14. That seems really easy to me- to put it in perspective- when I wore my HRM at Ironman last year, my average heart rate was 148 for the bike split.
Friel’s book says avg. hr and watts on an 8-10 mile TT gives a pretty good approximation of LT hr and watts. I’ve tried this on my computrainer, and get an avg. hr of 157 and an avg. watts of 230. This is compared with a HR of 144 and watts of 150 when my lactate was measured directly.
3.Friel also says that on his ramp test (start at 100 watts and ramp up by 20 watts per minute), most people can 3-4 minutes past LT. When I do this test, I konk out at about 340 watts. This means I’m lasting at least 6-10 minutes past LT (depending on which definition of LT we’re going with).
I’ve really appreciated everyone’s comments here! I’m part of a cycling group in Toronto I’ll try and put everyone’s suggested workouts on our website (lanternerouge.ca)and post that info. here again when it’s done.
keeping with this theme, the problem aloso may be that the tester was giving him a different value than what he was looking for. when people say LT, they often mean OBLA. LT, satrictly speaking in exercise physiology terms, occurs at blood lactate concentration of >= 1mM/L. OBLA (onset of blood lactate) occurs at 4mM/L. If he asked the tester for his LT, the tester may have given it to him ,not knowing what he really wanted to know was his OBLA. This is just a possibility, a misunderstanding.