The protocol for the determination of the speed/heart rate relationship during incremental
exercise previously described (so-called Conconi test) has been refined and in part
modified during 12 years of application. The new protocol calls for time-based increments
in exercise intensity that are uniform up to sub-maximal speeds and progressively
greater in the final phase. As in the original article (18), the speed/heart rate
relationship is linear at low to moderate speed and curvilinear from submaximal to
maximal speeds. A method is presented for the mathematical definition of this relationship,
with the calculation of the straight-line equation of the linear phase and the identificaition
of the point of transition from the linear to the curvilinear phase (deflection point
or heart rate break-point). Analysis of 300 tests selected at random from those in
our data base (more than 5,000 tests) has enabled us to show that the speed at which
the deflection point occurs is significantly lower (p < 0.001) than that at which
the acceleration of the finaI phase begins. This fact demonstrates that the break-point
is not brought on by the final acceleration called for in the test protocol. Analysis
of the speed/heart rate relationship allows for the determination of the following
additional functional indices: 1) maximal heart rate (in 21 athletes the maximal heart
rate attained in the test and that attained while racing were equal); 2) range of
heart beats defining the linear part of the speed/heart rate relationship; 3) range
of heart beats from the deflection point to maximal heart rate; and 4) maximal aerobic
exercise intensity, obtained through extrapolation of the straight-line equation to
maximal heart rate. Data are provided on the conditions of the test subject that modify
his speed/heart rate relationship, such as incomplete recovery from previous efforts,
inadequate warm-up, or inadequate test procedure with too rapid increments in exercise
intensity. Finally, criteria for test acceptability are presented.
Key words
Exercise intensity/heart rate relationship - heart rate break-point - incremental
exercise - anaerobic threshold
