Hi. Lately I’ve been running into an annoying problem of trying to do a challenging cardio workout but the endurance of my muscles fails before my cardio feels challenged. For example, if I am running, my legs feel tired before I feel my heartrate has been raised significantly, I do a lot of martial arts and do a lot of rounds on the heavy bag but I feel my legs and arms get fatigued faster than my heartrate and breathing. I’ve tried bouts of steady state training, as well as various intervals including HIIT. I think I’ve been blessed with good recovery when it comes to cardio, but is there something I’m missing here? Should I be working on muscle endurance? Or do I just need to find a different type of workout that I’ve never experienced before? Any insights are welcome!
Christine’s point makes sense to me. Sounds like you are perhaps doing more anaerobic work than aerobic. If you are getting over your aerobic threshold and tiring out your quads you many be working out to hard for a cardio bout. Have you tried a heart rate monitored as a measure of intensity? Obviously, if you are working at a heartrate of 85% or above of estimated max, for a long time, then you may be pushing too hard for aerobic training and at threshold of anaerobic.