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Front. Physiol. | doi: 10.3389/fphys.2019.01054

Comparison of Different Blood Lactate Threshold Concepts for Constant Load Performance Prediction in Spinal Cord Injured Handcyclists

 Carolin Stangier1*,  Thomas Abel1, Sebastian Zeller1, Oliver J. Quittmann1, Claudio Perret2 and Heiko K. Strüder1
  • 1Movement and Neurosciences, German Sport University Cologne, Germany
  • 2Institute of Sports Medicine, Swiss Paraplegic Center, Switzerland

Endurance capacity is one of the main performance determinants in handcycling. There are two exercise test procedures primarily applied to determine endurance capacity, to verify training adaptations and predict race performance. This study aims to evaluate the agreement of these applied concepts in handcycling. Methods:
In a repeated measures cross-over design, 11 highly trained male spinal cord injured (Th12 to L1) handcyclists (age; 40±9 yrs, height; 183±8 cm, body mass; 73.2±8.5 kg) performed a graded exercise test (GXT) and a lactate minimum test (LMT) to determine lactate threshold at 4 mmol·L-1 (LT4mmol·L-1) and lactate minimum (LM), respectively. The agreement of both lactate thresholds concepts for constant load performance prediction (change of ≤1 mmol·L-1 during the last 20 min) was evaluated within constant load tests (CLT; 30 min) at a power output (PO) corresponding to LT4mmol·L-1 and LM . Oxygen uptake ("V" ̇"O" _"2" ), respiratory exchange ratio (RER), heart rate (HR) and blood lactate (La) were measured during all tests.
PO at the corresponding thresholds (LT4mmol·L-1: 149±34 W vs. LM: 137±18 W) revealed no significant difference (p=0.06). During the CLT at LT4mmol·L-1 and LM, "V" ̇"O" _"2" and RPE were not significantly different. However, LA, RER and HR were significantly higher (p≤0.02) during CLT at LT4mmol·L-1. Bland-Altman plots indicate a wide range of dispersion for all parameters between both lactate threshold concepts. Evaluations of LT4mmol·L-1 and LM did not meet the criteria for constant load performance within the CLT for 33% and 17% of the athletes, respectively.
Both exercise tests and the corresponding lactate threshold concept revealed appropriate estimates to predict a steady state performance for the majority of participants. However, as PO determination at LT4mmol·L-1 and LM exceeds the criteria for constant load performance (increase of ≥1 mmol·L-1) for 33% and 17% respectively the current results indicate the common criteria for constant load performance (change of ± 1 mmol·L-1) might not be sufficiently precise for elite athletes in handcycling. Consequently, exercise test results of elite athletes should be analyzed individually and verified by means of several CLT.

Keywords: Endurance capacity, endurance exercise, spinal cord injury, lactate minimum test, Graded exercise test

Received: 24 Jan 2018; Accepted: 02 Aug 2019.

Copyright: © 2019 Stangier, Abel, Zeller, Quittmann, Perret and Strüder. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Carolin Stangier, German Sport University Cologne, Movement and Neurosciences, Cologne, Cologne, Germany,