There is a very good section in the book Training + Racing With A Power Meter that deals with ‘Guidelines For Optimal Intervals’ it asks ‘when should you stop doing repeats’ - Is there a point at which doing just one more interval is actually not helping you anymore? Essentially if the average power for an interval drops by a certain percentage then you know that you are going over the top of the diminishing marginal returns curve.
For a 20 minute interval, if the average drop in power is 3 to 5% then you’re there.
For a 5 minute interval its a drop of 5 to 7%
For a 1 minute interval, it’s 10 to 12%
This practice is great when you’re doing a ‘freestyle’ interval workout where you are the one in total control, but when being faced with (say) 2 more intervals in a SYSTM workout you are more likely to go beyond the point of diminishing returns and no longer be achieving the training stimulus for adaptation to occur. Dare we stop the session without finishing it 
??? Hmmmmm - it’s on the screen in front of you and it’s in your programme - that’s a tough challenge for even the most dedicated & conscientious cyclist! This is where having perhaps a broader overview of your Power Profile & Power Duration Curve can be helpful. FTP as we know is only a tiny part of the story - 4DP takes that a huge step further but for anyone who really wants to go beyond that to understand more about their weaknesses and strengths, CP (critical power) and MMP (mean maximal power) etc can add even more to the picture.
I would like to see workouts that perhaps recognise when you are beyond that point of diminishing returns and either adjust the level down to work on a different ‘training level’ or offer to terminate the workout early 
Coach Andy,
While sometimes it’s my heartrate, on quick intervals where it doesn’t come back quickly enough on the rest, what prompted my original question was because my legs felt like lead - from the get-go. I couldn’t get my heartrate UP, and couldn’t meet the cadence targets, so kept lowering the load percentages, until I just stopped and said, “Another day”! Then, I wondered if that was the best thing. Sounds like in this case, it probably was, but all the responses have given me some great insight on ways to best achieve the desired training effect for each workout. My MAP and AC are only average for my FTP, so I’ve wanted to work on those.
I do 3-4 System/RGT workouts a week (plus a couple weight workouts or runs), so I may have had too much load over the previous couple weeks.
Thanks again everyone.
| Coach.Andy.T Wahoo Sports Science
December 30 |
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I think setting the % a bit lower and working up to them. Running ERG till failure will mean you won’t be able to hold the power required to get the stimulus the session is looking for. Pausing changes the dynamic too. Cutting them short may be another way to go but I think B is the way to go. @JohnK has shared some very helpful info too!
Is it the breathing/heart rate or the legs that give up first with the efforts? Also what recovery are you having between efforts sessions and how many efforts sessions a week?
What you describe is what we call ‘overreaching’. Your body is telling you to take a day off. If you get on the bike and you can’t spin the pedals and your HR isn’t anywhere near where it should be, get off and do something else that isn’t a full on taxing event. Walk to the Local and have one (or two). That will do more for your fitness than you would imagine. The rule is ONE. Not six, definitely NOT ten.
I get this feeling sometimes if I haven’t warmed up well enough. I’ve started to do one of the 10-20 minute warmup sessions before the harder workouts so that I’ve had time to actually warm up before hitting the hard efforts. The in-workout warmups aren’t always enough for me.
The difference here is ‘my legs feel like lead billets’. That is your body saying ‘give me more time to recover and get back into the swing of things’. I’ve had that through several sessions and the thing I do is a three to five mile walk to keep the crud moving and to intake lots of fluids (yes coffee is a fluid) and to eat very sensibly.
Fair enough. I also get that feeling after trying to hit a hard workout after sitting at a desk for most of the day. Knowing your own context and what might be contributing to the feeling is key - is it something you can push through with some extra warmup or reduced intensity, or is it your body telling you it’s rest time?
Yep If you have been sitting all day, you will feel suggish. I’ve been there way to many times to count. Do the warm up. Still feeling like you have to lead billets for legs, time to think of something else. Are they coming around? maybe a little more warmup to get the fluids flowing. If you feel like taking on Mount Sufferlandria now, go do your workout…(and that’s what I did, Openers/Igniter are great to do a warmup with. Primers is too much).
This is what I do after a fitness test with increased watts. 97% for 2 weeks, recovery week, then 100%. Has worked well so far and I’ve been able to complete all sessions, which is a huge mental boost.
So thanks for posting this!
Can an unexpectedly high Aerobic decoupling (post-ride analysis) also help to confirm to you that the lead legs feeling was based on good intuition during the activity?
I like the idea of a walk to the local for a pint! 
@jmckenzieKOS
Sounds painful.
I’ve been in the aerobic decoupling scenario. Yep, the pint definitely helps, but in my case, it’s a walk to the local coffee shop (not a cafe as you are likely to make very poor nutritional choices there).