Reproducibility of Blood Lactate Concentration Rate under Isokinetic Force Loads

• Main Authors: Nico Nitzsche (Author), Lutz Baumgärtel (Author), Christian Maiwald (Author), Henry Schulz (Author)
• Format: Book
• Published: MDPI AG, 2018-11-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

(1) Background: Maximum isokinetic force loads show strongly increased post-load lactate concentrations and an increase in the maximum blood lactate concentration rate (<inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max), depending on load duration. The reproducibility of <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max must be known to be able to better assess training-related adjustments of anaerobic performance using isokinetic force tests. (2) Methods: 32 subjects were assigned to two groups and completed two unilateral isokinetic force tests (210° s⁻¹, Range of Motion 90°) within seven days. Group 1 (n = 16; age 24.0 ± 2.8 years, BMI 23.5 ± 2.6 kg m⁻², training duration: 4.5 ± 2.4 h week⁻¹) completed eight repetitions and group 2 (n = 16; age 23.7 ± 1.9 years, BMI 24.6 ± 2.4 kg m⁻², training duration: 5.5 ± 2.1 h week⁻¹) completed 16 repetitions. To determine <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max, capillary blood (20 µL) was taken before and immediately after loading, and up to the 9th minute post-load. Reproducibility and variability was determined using Pearson and Spearman correlation analyses, and variability were determined using within-subject standard deviation (S_w) and Limits of Agreement (LoA) using Bland Altman plots. (3) Results: The correlation of <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max in group 1 was r = 0.721, and in group 2 r = 0.677. The S_w of <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max was 0.04 mmol L⁻¹ s⁻¹ in both groups. In group 1, <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max showed a systematic bias due to measurement repetition of 0.02 mmol L⁻¹ s⁻¹ in an interval (LoA) of ±0.11 mmol L⁻¹ s⁻¹. In group 2, a systematic bias of −0.008 mmol L⁻¹ s⁻¹ at an interval (LoA) of ±0.11 mmol L⁻¹ s⁻¹ was observed for repeated measurements of <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max. (4) Conclusions: Based on the existing variability, a reliable calculation of <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max seems to be possible with both short and longer isokinetic force loads. Changes in <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max above 0.11 mmol L⁻¹ s⁻¹ due to training can be described as a non-random increase or decrease in <inline-formula> <math display="inline"> <semantics> <mover accent="true"> <mi>V</mi> <mo>˙</mo> </mover> </semantics> </math> </inline-formula>La_max.

Item Description

2075-4663
10.3390/sports6040150