Is HR lagging due to lack of muscular endurance?

[pelotoncamden]

Started riding/racing again after an 18 year lay-off and have been able to log as of today, 3564 miles since January 1st and approximately 4564 since my return in September 2006. I've lost over 37lbs and am very happy with my gains physically but feel as though my muscular endurance is holding me back with regards to vo2 and anaerobic workouts.

I'm 38 y/o, am 5'8" tall, and weight 155lbs and my current FTP is 280W. My CTL as of today is 88.6. In reviewing my workouts in CP for this season, I've found 1 workout - actually a crit where my heart rate got above 175BPM - max was 177BPM and averaged 164bpm for 30 minutes. When performing vo2 max intervals, I'm hard pressed to hit 170bpm (usually around 168 - 169) and feel as though my legs give out trying to keep the watts high before I'm so winded I can't continue. I would think at my age, I should still be able to get heart rates in the 180's. Am I correct in my assumption that my muscular endurance is lagging behind my aerobic/anaerobic fitness levels or is it something else? Am I seeing this all wrong and should actually see this as something good?

I know that training with power means not focusing on HR as much but as the saying goes, "you can't teach an old dog new tricks!

Thanks in advance for your time.

 

[daveryanwyoming]

... When performing vo2 max intervals, I'm hard pressed to hit 170bpm (usually around 168 - 169) and feel as though my legs give out trying to keep the watts high before I'm so winded I can't continue. ...

It's very unusual to hit max HR during a 3 to 5 minute VO2 max interval. During a L4 interval it usually takes my HR 6 to 7 minutes just to come up to the average for the interval and even though it keeps rising for the full 20 minute effort it still doesn't hit max. The best way I know of to hit max is to preload with 8 to 10 minutes of hard effort and then give it everything you've got for the final 30 seconds to minute. Sometimes racing can do this if you have to respond to a hard attack after some steady hard efforts.

It sounds like you're going too hard during your L5 efforts and going anaerobic before you get into full VO2 max range with maximal breathing. The first minute or two of L5 efforts usually doesn't feel too bad but by two and a half minutes it catches up and breathing should be maxed out, hold it for another couple of minutes and that's a good VO2 max interval.

Remember the whole point is to stress the metabolic systems that run at maximal breathing so you have to get your breathing up to max and then hold it longer for training effect. If you're trying to get your HR up fast by starting hard then you're more likely doing a shorter L6 anaerobic effort which works a completely different system.

-Dave

 

[daveryanwyoming]

Just a postscript, I gave the L4/HR example above because I don't usually wear the HR strap anymore and didn't think I had HR data for any recent L5 intervals, but I took a look at workouts and found this set of L5 repeats I did about a month ago where I wore the strap.

My max recorded HR in the last 6 months is 185 bpm, take a look at how it takes over a minute for my HR to reach the average for the interval (158) and how it continues to climb till the end of the effort but still only reaches 166(roughly the average for longer L4 repeats) and never even approaches 185 bpm.

These were definitely L5 intervals based on my max breathing, how long I could sustain them at nearly the same power output and the power relative to my FTP at the time.

Anyway, I've attached a screenshot of that effort with power and HR displayed. I'd be very surprised if you could actually hit your max HR during a VO2 max effort and if you're trying, you're probably going out much too hard.

 

[pelotoncamden]

Thanks for the feedback and I think you're right, I'm trying to get to max heart rate during a vo2 max interval which doesn't make sense. I think I should bag the strap and focus on my power zones!!