Validity of the Modified Conconi Running Test

Abstract

The aim of this study was to assess the validity of a fast ramp treadmill protocol for determination of the heart rate deflection point (HR (dp)) and speed of deflection (S (dp)) in trained runners. Fifty-one trained male runners performed a standard (T (stand); speed increase 1 km . h (-1) every 60 s) and a fast (T (fast); speed increase 1 km . h (-1) every 30 s) incremental treadmill test until volitional exhaustion. Heart rate was continuously recorded, and the HR (dp) was estimated after data averaging as the point of deflection in the linear speed/HR relationship. The HR (dp) and S (dp) recorded in T (fast) were compared with the corresponding values obtained in T (stand) by examining the Student's T-test, correlation coefficient (r), and limits of agreement (LoA). The HR (dp) recorded during standard and fast treadmill protocol were highly correlated (r = 0.92, p < 0.001) and similar to each other (p = 0.79). In contrast, S (dp) was highly correlated (r = 0.91, p < 0.001), but increased significantly with the faster ramp function (p < 0.001). No evidence of systematic bias was evident in the HR (dp) (95 % LoA of 0.2 +/- 7.3 bpm), while a uniform, systematic bias was evident for S (dp) in the T (fast) (95 % LoA of 1.6 +/- 1.5 km x h (-1)). We conclude that a fast ramp treadmill protocol (speed increase 1 km x h (-1) every 30 s) may be used for determination of the HR (dp) in trained runners, while S (dp) is protocol dependent and caution is warranted regarding its practical applicability.

Reproducibility and Variability of the Conconi Test Analysis

“…This is consistent with the finding of Sentija et al [12], who found a very good reproducibility for HR dp comparing different kind of modified Conconi test protocols, while speed was dependent of the test protocol. Protocols with longer duration of the bouts resulted in a slower speed at DP, without changing HR dp compared with protocols with shorter bouts.…”

“…According to the existing literature, we can conclude that DP can be identified in the majority of the HR/PO graphs, but in few cases (0 to 7.6%) it may be impossible to see a deflection [3,12,14]. In our experience, the lack of a DP mostly appears in people that are not used to perform to exhaustion and stop the test as soon as acidaemia appears.…”

“…In a review article about the concept of HR dp Bodner and Rhodes [15] concluded that the degree of deflection is highly dependent upon the type of protocol used and HR dp appears to be reliable when a DP in the PO/HR graph can be identified. Sentija et al [12] showed that different kind of incremental protocol may be used for determination of identical HR dp , while speed at DP is protocol dependent. Lepretre et al [16] demonstrated that in well-trained subjects HR dp coincided with the optimal cardiac work for which maximal stroke volume was attained.…”

“…In our experience, the lack of a DP mostly appears in people that are not used to perform to exhaustion and stop the test as soon as acidaemia appears. In literature, different authors deny the concept of the DP, while others confirm the concept and could correlate the DP with the anaerobic threshold and HR dp with maximal stroke volume [7][8][9][10][11][12][13].…”

What we may learn from lactate time curves by means of piecewise polynomial regression methods.

“…Internationally, the "maximum lactate steady-state" (MLss) is defined as the highest constant lactate level which can be maintained by the athlete over 30 minutes (8). In this phase II, sometimes called aerobic-anaerobic transition, elimination can still compensate lactate production (9). Finally, in phase III lactate will increase almost exponentially and therefore in athletes this phase will last only for a limited time interval as steady state conditions have been lost.…”