Isometrics: What causes the failure, energy system or LT or something else?
A friendly single leg wall sit competition among conditioned individuals (with no contraindications) took place the other day“ and lasted no longer than a 1 minute 15 sec.
I have to wonder, what causes the failure first? Engergy system-mostly ATP/PC & Glycolosis, Lactate threshold or something else? I’ve read research indicating that the myosin heads decrease their movement almost 3-fold during isometric exercise which I supposed has to do with a more static sarcomere. This leads me to believe they are using less ATP and that it is the lactate threshold. What do you think? Anyone know of research on LT and isometrics?
Lactate in Fast and Slow Twitch Skeletal Muscle Fibres of Man during Isometric Contraction
Per Tesch, Jan KarlssonArticle first published online: 8 DEC 2008
Here, check this out. Also expresses the involvement of slow v/s fast twitch fibres. I haven’t read it all the way through yet but looks like it might back your theory.
Adrianne, as I read your question, I got really excited.
I thought this study might be helpful to you in determining what causes failure AT/LT or failure of the anaerobic energy system.
Here is the link:
Medicine & Science in Sports:
Recovery of muscular endurance following submaximal, isometric exercise: PDF Only
Recovery of muscular endurance following submaximal, isometric exercise
STULL, ALAN G.; KEARNEY, JAY T.
From the study, this finding stood out for me specifically. Hope you find it helpful:
“Past research would suggest that the most critical biochemical imbalances associated with this type of activity investigated in the present study are the decreased CP and increased lactate and associated decrease in pH. There may also be a potassium ion imbalances and an efflux of phosphate ions that concommittantly develop. The composite of the reactions would almost certainly exert a negative influence on the ability of the contractile apparatus to generate force.”
Best to you.
