TY - JOUR
T1 - Effect of a fatiguing ultratrail on the graded energetically optimal stride frequency
AU - Vernillo, Gianluca
AU - Mater, Adrien
AU - Doucende, Gregory
AU - Cassirame, Johan
AU - Mourot, Laurent
N1 - Funding Information:
The authors thank our participants, as well as Arash Khassetarash, Will Juillaguet, and all the staff of CREPS de Font Romeu. The authors also thank Hayley L. Patmore for checking the article for English.
Publisher Copyright:
© 2020 Human Kinetics, Inc.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/10
Y1 - 2020/10
N2 - Purpose: To study the consequences of a fatiguing ultratrail run of 6 hours on self-optimizing capability during uphill and downhill (DR) running. Methods: The authors collected temporal stride kinematics and metabolic data in 8 (experimental group) male runners before and after the ultratrail run and in 6 (control group) male ultramarathon runners who did not run but stayed awake and performed normal, daily physical activities avoiding strenuous exercises over the 6-hour period. For each subject, preferred and optimal stride frequencies were measured, where stride frequency was systematically varied above and below the preferred one (±4% and ±8%) while running 3 conditions on level, 5% uphill, or 5% DR in a randomized order. Results: Preferred and optimal stride frequencies across grade, group, and time showed no significant differences (P ≥.184). Metabolic cost and the energetically optimum metabolic cost showed a grade × group × time interaction (P ≥.011), with an ∼11% increase in the 2 variables only during the DR bouts (P ≥.037). Conclusions: Despite maintaining similar dynamics of stride frequency adjustments during the DR bout, the experimental group was not able to optimize its gait. This suggests that the DR section of ultratrail runs can introduce a perturbing factor in the runners' optimization process, highlighting the need for incorporating DR bouts in the training programs of ultratrail runners to minimize the deleterious effects of DR on the energetically optimal gait.
AB - Purpose: To study the consequences of a fatiguing ultratrail run of 6 hours on self-optimizing capability during uphill and downhill (DR) running. Methods: The authors collected temporal stride kinematics and metabolic data in 8 (experimental group) male runners before and after the ultratrail run and in 6 (control group) male ultramarathon runners who did not run but stayed awake and performed normal, daily physical activities avoiding strenuous exercises over the 6-hour period. For each subject, preferred and optimal stride frequencies were measured, where stride frequency was systematically varied above and below the preferred one (±4% and ±8%) while running 3 conditions on level, 5% uphill, or 5% DR in a randomized order. Results: Preferred and optimal stride frequencies across grade, group, and time showed no significant differences (P ≥.184). Metabolic cost and the energetically optimum metabolic cost showed a grade × group × time interaction (P ≥.011), with an ∼11% increase in the 2 variables only during the DR bouts (P ≥.037). Conclusions: Despite maintaining similar dynamics of stride frequency adjustments during the DR bout, the experimental group was not able to optimize its gait. This suggests that the DR section of ultratrail runs can introduce a perturbing factor in the runners' optimization process, highlighting the need for incorporating DR bouts in the training programs of ultratrail runners to minimize the deleterious effects of DR on the energetically optimal gait.
KW - Metabolic cost
KW - Optimization
KW - Slope
KW - Ultramarathon
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U2 - 10.1123/IJSPP.2019-0666
DO - 10.1123/IJSPP.2019-0666
M3 - Article
AN - SCOPUS:85095435844
VL - 15
SP - 1340
EP - 1343
JO - International Journal of Sports Physiology and Performance
JF - International Journal of Sports Physiology and Performance
SN - 1555-0265
IS - 9
ER -