RRC Archives

The pump comes from the fact that the muscles are not relaxing. They can't relax because the local fuel is being consumed faster than it is being produced. This local fuel is called ATP. Muscles are spring loaded to contract by fuel already in the mechanism.

1) ATP binds 2) Muscles contract 3) ATP is converted to ADP. 1) More ATP binds thus allowing muscular contraction.

When people die ATP gets used up and the muscle can not extend. With both opposing muscles contracted limbs get stiff. I think it is somewhat haunting that the feeling we get when we pump is phenomenologically related to rigor mortis.
http://en.wikipedia.org/wiki/Rigor_mortis

The pump makes muscle performance progressively worse due to the fact that tight muscles impede blood flow.

The pump does not have a lot to do with the production of lactate directly; this was well known before the research cited was done.

That is really interesting about the local myocyte lactate shuttle. We were taught that lactate was carried back to the liver for use. It makes sense that with the right prompting (training) the local muscle adapts to use lactate.
But the proper training sounds like the difficult part. Interval training for the forearms. Multiple powerful flexor muscle group contractions for a brief period of time followed by a short rest and repeat? Isn't that what interval training is when running or cycling (or lifting weights)?
It seems that this would still be one facet of a larger training program including light resistance more aerobic oriented forearm exercises (light climbing).