How can i log the current threads count?

Hello, i log times using script in this way:

for(result in testRunner.results) {
log.info result.testStep.label + '  ' + result.timeTaken + ' ms'
}

Also i want to log the count of threads thats is running concurrently. I found getRunningThreadCount()  but i don't know how can i apply it.

Any suggest?
Thank in advance
Cyntia
P.S: Sorry for my english