No, the study is by Persson, who measured it in Standardbreds.
Some horses may reach LA4 at this heartrate, but I've
> never seen it happen.
I would agree in a fit racehorse. We have unfit horses on the treadmill
at Cal Poly all the time and see it often, though they don't go far
above LA4.
Another thing to know is that heartrate is not a direct
> reflection of LA status--you have to sustain anaerobic work for a while
> before climbing above 4 mmol.
I would agree there's not a direct reflection, but certainly a
relationship? After all, anaerobic metabolism and therefore LA
production is a compensatory response to the heart's inability to
deliver sufficient oxygen to the muscle tissue. Also, I know I've seen
alot of maximal effort SET's where lactates zoomed to above 20 mmol in a
minute and over 30 mmol in 2 min. (In other words, your average TB
race). I assume you're talking about minimally anaerobic work to get
above 4 mmol, not the kind of exercise levels you see in your horses.
In endurance horses, I just can't imagine a
> circumstance where racehorse-level lactates are reached.
Short of a total breakdown of rider judgement, me neither. Personally,
I wonder if there's a statistical correlation between rider "ambition"
and LA levels/glycogen depletion/muscle injury, what do you think? :->
Susan Evans
California State Polytechnic University