Legs giving out before I reach max HR. Ideas?

DanEvs

At the start of the year I could regularly run high HR's, way up in the high 190's (I'm 27 and do a bit of XC racing and some TT's). Problem is that just 6months on (and a knee op) I'm struggling to reach my max HR at any point during a ride. I'm definitely fitter than I was as the start of the year and I'm riding a lot with all sorts of hill intervals, sprint intervals etc but I'm just not seeing the big numbers on the HRM. :?

Is this a result of my greater fitness or is it something like my cadence being too slow and my legs running out of power before I can get the cardio really going? I have always tended to push the big gears instead of spinning so I'm tempted to say that's not the problem. Is there something else I'm missing or should I just stop thinking about it and carry on?

Edit: In this period I've changed my diet quite a lot, gone from fast food and fry-ups to pasta, rice, chicken, fruit, veg etc. Could this be the difference?

TarmacExpert

In my experience what you describe is a symptom of muscle fatigue, and an appropriate amount of rest is the solution. Have you been tapering for your races, or just fairly continuously training and racing?

Alex_Simmons/RST

If your power and speed is better, not sure what the problem is?

HR is not a measure of performance.

DanEvs

Alex_Simmons/RST wrote:

If your power and speed is better, not sure what the problem is?

HR is not a measure of performance.

That kind of explains it then. I was just wondering if there was an extra bit of performance I could find by getting my HR up that extra few BPM. :?

I think I'll just forget about it and get on with my training. Thanks for the replies.

TarmacExpert

Alex_Simmons/RST wrote:

If your power and speed is better, not sure what the problem is?

HR is not a measure of performance.

The problem is that his power and speed might be even better if the performance bottleneck were removed and the rest of his body were able to make sufficient demands on his cardiovascular system to reach his normal heart rate.

However in his last post he refers to "a few bpm" which I would agree is nothing to worry about. I thought from the first post he was talking about more like the 20-30bpm drop in achievable heart rate that I have experienced when in sustained heavy training before resting for a competition.

Alex_Simmons/RST

TarmacExpert wrote:

Alex_Simmons/RST wrote:

If your power and speed is better, not sure what the problem is?

HR is not a measure of performance.

The problem is that his power and speed might be even better if the performance bottleneck were removed and the rest of his body were able to make sufficient demands on his cardiovascular system to reach his normal heart rate.

However in his last post he refers to "a few bpm" which I would agree is nothing to worry about. I thought from the first post he was talking about more like the 20-30bpm drop in achievable heart rate that I have experienced when in sustained heavy training before resting for a competition.

However his heart stroke volume may have increased with training (quite normal) meaning that even though HR is lower, his cardiac output may indeed by higher.

As a result, it is not uncommon for max HR to fall a little when you are fitter.

HR is not only not a measure of performance, it is often a red herring wrt to other aspects of training.