[Comparison of heart rate to lactate threshold and to Conconi's threshold in children]. 
The heart rate (HR) at the lactate threshold was determined on a treadmill in 59 children with an average age of 11.8 years.  45 minutes later, they had to go through a vita maxima test on a bicycle ergometer.  The load was increased stepwise by 10 Watt/min.  During the tests HR was registered continually and stored every 5 seconds.  In 52 children the characteristic break point was evident; in 7 children no break point could be found - in 2 children, because they had stopped the exercise before reaching the lactate threshold, and in 5 children because their HR increased linearly from the beginning until the end of the load application.  HR at the break point correlated very strongly with HR at the lactate threshold (r = 0.99).  Therefore the authors are of the opinion that the introduced modification of the Conconi test can substitute the invasive lactate threshold determination in children.