A Novel Approach to Determining the Alactic Time Span in Connection with Assessment of the Maximal Rate of Lactate Accumulation in Elite Track Cyclists

Abstract

Purpose: Following short-term all-out exercise, the maximal rate of glycolysis is frequently assessed on the basis of the maximal rate of lactate accumulation in the blood. Since the end of the interval without significant accumulation (talac) is 1 of 2 denominators in the calculation employed, accurate determination of this parameter is crucial. Although the very existence and definition of talac, as well as the validity of its determination as time-to-peak power (tPpeak), remain controversial, this parameter plays a key role in anaerobic diagnostics. Here, we describe a novel approach to determination of talac and compare it to the current standard. Methods: Twelve elite track cyclists performed 3 maximal sprints (3, 8, and 12 s) and a high-rate, low-resistance pedaling test on an ergometer with monitoring of crank force and pedaling rate. Before and after each sprint, capillary blood samples were taken for determination of lactate accumulation. Fatigue-free force–velocity and power–velocity profiles were generated. talac was determined as tPpeak and as the time point of the first systematic deviation from the force–velocity profile (tFf). Results: Accumulation of lactate after the 3-second sprint was significant (0.58 [0.19] mmol L−1; P < .001, d = 1.982). tFf was <3 seconds and tPpeak was ≥3 seconds during all sprints (P < .001, d = − 2.111). Peak power output was lower than maximal power output (P < .001, d = −0.937). Blood lactate accumulation increased linearly with increasing duration of exercise (R2 ≥ .99) and intercepted the x-axis at ∼tFf. Conclusion: Definition of talac as tPpeak can lead to incorrect conclusions. We propose determination of talac based on tFf, the end of the fatigue-free state that may reflect the beginning of blood lactate accumulation.

A Novel Approach to the Determination of Time- and Fatigue-Dependent Efficiency during Maximal Cycling Sprints

“…The finding that none of our participants attained the maximal calculated power output during the sprints is in line with our previous observations [ 28 , 30 ]. Due to the initial resistance during the acceleration phase of the sprints, when the athletes reached the point of producing the highest power, they were potentially fatigued.…”

“…The motoric test was carried out 30 min after the 12-s sprint and involved each participant cycling for 6 s at the maximal rate and with low resistance [ 30 ]. This setting enabled a pedaling rate of ≥160 rpm to be attained within the first 3 s, thereby generating data at high pedaling rates.…”

“…To avoid overestimation of the maximal power output in connection with the fatigue-free interval during the first seconds of exercise [ 30 ], P max (t) was there re-defined as follows: …”

The Influence of Pedaling Frequency on Blood Lactate Accumulation in Cycling Sprints

“…Another method proposed by Mader [12], estimates lactic power by measuring the change in lactate concentration (ΔBLC) after a sprint test in relation to the test duration. This approach was for instance employed during a maximal isokinetic cycle sprint [13,14] and utilizes the determined maximal rate of lactate formation in the blood as a valid indicator of maximal glycolytic power [15]. It is proposed that higher rates of lactate formation correspond to higher glycolytic flux [16][17][18][19].…”

“…This finding was subsequently supported by Hauser et al [24], who reported the highest rates after 6-second sprints when comparing sprint durations ranging from 6 to 20 seconds. Moreover, a study conducted with elite track cycling sprinters demonstrated a linear increase in ΔBLC from approximately 2.5 seconds to 12 seconds, indicating a potentially constant glycolytic flux during this time range [15]. The authors interpreted these linear segments as nearly linear parts of an exponential function, representing lactate accumulation during maximal efforts lasting up to 60 seconds or longer.…”