Research article - (2022)21, 214 - 223
DOI:
https://doi.org/10.52082/jssm.2022.214
Lack of Evidence for Crossover Fatigue with Plantar Flexor Muscles
Saman Hadjizadeh Anvar1,2,, Mohammad Reza Kordi2, Shahab Alizadeh1, Emma Ramsay1, Fatemeh Shabkhiz2, David G. Behm1
1School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s Newfoundland and Labrador (NL), Canada
2Faculty of Physical Education & Sport Sciences, University of Tehran, Tehran, Iran

Saman Hadjizadeh Anvar
✉ School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL, Canada
Email: shadjizadeha@mun.ca
Received: 04-03-2022 -- Accepted: 01-04-2022
Published (online): 01-06-2022

ABSTRACT

The occurrence and mechanisms underlying non-local or crossover muscle fatigue is an ongoing issue. This study aimed to investigate crossover fatigue of the plantar flexor muscles. Sixteen recreationally active males (n = 6) and females (n = 10) visited the laboratory for four sessions and performed a single 5-s pre-test maximal voluntary isometric contraction (MVIC) with each plantar flexors muscle. Thereafter, the fatigue intervention involved two 100-s MVICs (60-s recovery) with their dominant plantar flexors or rested for 260-s (control). Subsequently, in two separate sessions, Hoffman reflexes (H-reflex) were evoked in the non-dominant, non-exercised, leg before and following the dominant leg fatigue or control intervention (Fatigue-Reflex and Control-Reflex conditions). MVIC forces and volitional (V)-waves were monitored in the non-dominant leg in the other two sessions (Fatigue-MVIC and Control-MVIC) before and after the intervention (fatigue or control) as well as during 12 repeated MVICs and immediately thereafter. Despite the force reduction in the dominant leg (42.4%, p = 0.002), no crossover force deficit with single (F(1,9) = 0.02, p = 0.88, pÆž2 = 0.003) or repeated (F(1,9) = 0.006, p = 0.93, pÆž2 = 0.001) MVIC testing were observed. The H-reflex did not change after the fatigue (F(1,7) = 0.51; p = 0.49; pÆž2 = 0.06) or repeated MVICs (F(1,8) = 0.27; p = 0.61; pÆž2 = 0.03). There were also no crossover effects of fatigue on the V-wave with single (F(1,8) = 3.71, p = 0.09, pÆž2 = 0.31) or repeated MVICs (F(1,6) = 1.45, p = 0.27, pÆž2 = 0.19). Crossover fatigue was not evident with the plantar flexors nor any significant changes in H-reflex and V-waves in the soleus muscle. This finding suggests that crossover fatigue may not necessarily occur in slow-twitch predominant muscle groups.

Key words: Non-local muscle fatigue, soleus, fatigue, Hoffman reflex, V-wave

Key Points
  • There were no significant crossover impairments in muscle endurance suggesting that when unilaterally training the plantar flexors, crossover decrements may not be an issue.
  • Unilaterally fatiguing the plantar flexors induces only a trivial chance of experiencing single or discrete contraction force or strength decrements in the contralateral limb.








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