Is Maximal Lactate Accumulation Rate Promising for Improving 5000-m Prediction in Running?

Endurance running performance can be predicted by maximal oxygen uptake (V̇O2max), the fractional utilisation of oxygen uptake (%V̇O2max) and running economy at lactate threshold (REOBLA). This study aims to assess maximal lactate accumulation rate (cLamax) in terms of improving running performance prediction in trained athletes. Forty-four competitive female and male runners/triathletes performed an incremental step test, a 100-m sprint test and a ramp test to determine their metabolic profile. Stepwise linear regression was used to predict 5000-m time trial performance. Split times were recorded every 200-m to examine the 'finishing kick'. Females had a slower t5k and a lower V̇O2max, cLamax, 'finishing kick' and REOBLA. Augmenting Joyner's model by means of cLamax explained an additional 4.4% of variance in performance. When performing the same analysis exclusively for males, cLamax was not included. cLamax significantly correlated with %V̇O2max (r=-0.439, p=0.003) and the 'finishing kick' (r=0.389, p=0.010). cLamax allows for significant (yet minor) improvements in 5000-m performance prediction in a mixed-sex group. This margin of improvement might differ in middle-distance events. Due to the relationship to the 'finishing kick', cLamax might be related to individual pacing strategies, which should be assessed in future research.

Maximal lactate accumulation rate and post-exercise lactate kinetics in handcycling and cycling.

The aim of this study was to assess lactate kinetics, maximal lactate accumulation rate (⩒Lamax) and peak power output (POmax) in a 15-s all-out exercise in handcycling (HC) and cycling (C) in terms of (1) reliability, (2) differences and (3) correlations between HC and C. Eighteen female and male competitive triathletes performed two trials (separated by one week) of a 15-s all-out sprint test in HC and C. Tests were performed in a recumbent racing handcycle and on the participants' own road bike that were attached to an ergometer. Reliability was assessed using intraclass correlation coefficient (ICC). POmax and ⩒Lamax demonstrated high reliability in HC (ICC = 0.972, ICC = 0.828) and C (ICC = 0.937, ICC = 0.872). POmax (d = -2.54, P < 0.0005) and ⩒Lamax (d = -1.62, P < 0.0005) were lower in HC compared to C. POmax and ⩒Lamax correlated in HC (r = 0.729, P = 0.001) and C (r = 0.710, P = 0.001). There was no significant correlation between HC and C in POmax (r = 0.442, P = 0.066) and ⩒Lamax (r = 0.455, P = 0.058). Whereas the exchange velocity of lactate (k1) was similar in HC and C, the removal velocity (k2) was significantly higher in HC. ⩒Lamax and POmax during sprint exercise are highly reliable and demonstrate a correlation in both HC and C. However, since ⩒Lamax and POmax are significantly higher in C and not correlated between HC and C, ⩒Lamax and POmax seem to be extremity-specific.

Effects of low- and high-intensity exercise on emotional face processing: an fMRI face-matching study.

Physical exercise has positive effects on mood and it reduces clinical depression and states of anxiety. While previous work mostly used subjective measures to study the effect of exercise upon emotions, this study for the first time employed blood oxygen level dependent functional magnetic resonance imaging (fMRI) to unravel associated neuronal changes of the emotional face-processing network in response to acute exercise. A total of 25 male athletes underwent fitness assessments to define two standardized 30 min exercise interventions (low and high intensity). The Positive and Negative Affect Schedule (PANAS) was completed pre- and post-exercise and neuronal responses to neutral, happy and fearful facial expressions were determined using an fMRI-based face-matching paradigm. Complete data sets were acquired in 21 participants (mean age, 27.2 ± 4.2 years). Both exercise interventions induced significant increases of the PANAS positive affect scale. Modulations of brain activation patterns following acute exercise were found only for fearful facial stimuli vs forms: reduced brain activation in posterior cingulate cortex/precuneus for the low condition and reduced activity in caudate nucleus and ventral anterior putamen for the high condition. In conclusion, this study provides first in vivo evidence that acute strenuous exercise interferes with emotional face-processing brain regions in an emotion type-specific manner.