TY - JOUR
T1 - Power Output Manipulation from Below to Above the Gas Exchange Threshold Results in Exacerbated Performance Fatigability
AU - Brownstein, Callum G.
AU - Pastor, Frederic Sabater
AU - Mira, José
AU - Murias, Juan M.
AU - Millet, Guillaume Y.
N1 - Publisher Copyright:
© 2022 Lippincott Williams & Wilkins.
PY - 2022/11/1
Y1 - 2022/11/1
N2 - Introduction Performance fatigability is substantially greater when exercising in the severe- versus heavy-intensity domain. However, the relevance of the boundary between moderate- and heavy-intensity exercise, the gas exchange threshold (GET), to performance fatigability is unclear. This study compared alterations in neuromuscular function during work-matched exercise above and below the GET. Methods Seventeen male participants completed work-matched cycling for 90, 110, and 140 min at 110%, 90%, and 70% of the GET, respectively. Knee extensor isometric maximal voluntary contraction (MVC), high-frequency doublets (Db100), low- to high-frequency doublet ratio (Db10:100), and voluntary activation were measured at baseline, 25%, 50%, 75%, and 100% of task completion. During the initial baseline visit and after each constant work rate bout, ramp-incremental exercise was performed, and peak power output and oxygen uptake (V?O-2peak) were determined. Results After the 70% and 90% GET trials, similar reductions in MVC (-14% +/- 6% and -14% +/- 8%, respectively, P = 0.175) and Db100 (-7% +/- 9% and -6% +/- 9%, respectively, P = 0.431) were observed. However, for a given amount of work completed, reductions in MVC (-25% +/- 15%, P = 0.008) and Db100 (-12% +/- 8%, P = 0.029) were up to 2.6-fold greater during the 110% than the 90% GET trial. Peak power output and V?O-2peak during ramp-incremental exercise were reduced by 7.0% +/- 11.3% and 6.5% +/- 9.3%, respectively, after the 110% GET trial relative to the baseline ramp (P <= 0.015), with no changes after the moderate-intensity trials (P >= 0.078). Conclusions The lack of difference in fatigability between the trials at 70% and 90% GET, coupled with the greater fatigability at 110% relative to 90% GET, shows that exceeding the moderate- to heavy-intensity boundary has implications for performance fatigability, while also impairing maximal exercise performance capacity.
AB - Introduction Performance fatigability is substantially greater when exercising in the severe- versus heavy-intensity domain. However, the relevance of the boundary between moderate- and heavy-intensity exercise, the gas exchange threshold (GET), to performance fatigability is unclear. This study compared alterations in neuromuscular function during work-matched exercise above and below the GET. Methods Seventeen male participants completed work-matched cycling for 90, 110, and 140 min at 110%, 90%, and 70% of the GET, respectively. Knee extensor isometric maximal voluntary contraction (MVC), high-frequency doublets (Db100), low- to high-frequency doublet ratio (Db10:100), and voluntary activation were measured at baseline, 25%, 50%, 75%, and 100% of task completion. During the initial baseline visit and after each constant work rate bout, ramp-incremental exercise was performed, and peak power output and oxygen uptake (V?O-2peak) were determined. Results After the 70% and 90% GET trials, similar reductions in MVC (-14% +/- 6% and -14% +/- 8%, respectively, P = 0.175) and Db100 (-7% +/- 9% and -6% +/- 9%, respectively, P = 0.431) were observed. However, for a given amount of work completed, reductions in MVC (-25% +/- 15%, P = 0.008) and Db100 (-12% +/- 8%, P = 0.029) were up to 2.6-fold greater during the 110% than the 90% GET trial. Peak power output and V?O-2peak during ramp-incremental exercise were reduced by 7.0% +/- 11.3% and 6.5% +/- 9.3%, respectively, after the 110% GET trial relative to the baseline ramp (P <= 0.015), with no changes after the moderate-intensity trials (P >= 0.078). Conclusions The lack of difference in fatigability between the trials at 70% and 90% GET, coupled with the greater fatigability at 110% relative to 90% GET, shows that exceeding the moderate- to heavy-intensity boundary has implications for performance fatigability, while also impairing maximal exercise performance capacity.
KW - Contractile function
KW - Corticospinal excitability
KW - Exercise intensity
KW - Intensity domains
KW - Motoneuron excitability
KW - Neuromuscular function
KW - Voluntary activation
UR - https://www.scopus.com/pages/publications/85139988889
U2 - 10.1249/MSS.0000000000002976
DO - 10.1249/MSS.0000000000002976
M3 - Article
C2 - 36007155
AN - SCOPUS:85139988889
SN - 0195-9131
VL - 54
SP - 1947
EP - 1960
JO - Medicine and Science in Sports and Exercise
JF - Medicine and Science in Sports and Exercise
IS - 11
ER -