Unilateral isometric muscle fatigue decreases force production and activation of contralateral knee extensors but not elbow flexors

Abstract

Nonlocal muscle fatigue occurs when fatiguing 1 muscle alters performance of another rested muscle. The purpose of the study was to investigate if fatiguing 2 separate muscles would affect the same rested muscle, and if fatiguing the same muscle would affect 2 separate muscles. Twenty-one trained males participated in 2 studies (n = 11; n = 10). Subjects performed 2 pre-test maximum voluntary contractions (MVCs) with the nondominant knee extensors. Thereafter they performed two 100-s MVCs with their dominant knee extensors, elbow flexors, or rested. Between and after the sets, a single MVC with the nondominant rested knee extensors was performed. Subsequently, 12 nondominant knee extensors repeated MVCs were completed. Force, quadriceps voluntary activation (VA), and electromyography (EMG) were measured. The same protocol was employed in study 2 except the nondominant elbow-flexors were tested. Study 1: Compared with control conditions, a significant decrease in nondominant knee extensors force, EMG, and VA was found under both fatiguing conditions (P ≤ 0.05; effect size (ES) = 0.91-1.15; 2%-8%). Additionally, decrements in all variables were found from the first post-intervention MVC to the last (P ≤ 0.05; ES = 0.82-2.40; 9%-20%). Study 2: No differences were found between conditions for all variables (P ≥ 0.33; ES ≤ 0.2; ≤3.0%). However, all variables decreased from the first post-intervention MVC to the last (P ≤ 0.05; ES = 0.4-3.0; 7.2%-19.7%). Whereas the rested knee extensors demonstrated nonlocal effects regardless of the muscle being fatigued, the elbow-flexors remained unaffected. This suggests that nonlocal effects are muscle specific, which may hold functional implications for training and performance.

Effect of unilateral knee extensor fatigue on force and balance of the contralateral limb

“…It can be concluded that the lack of changes in non-fatigued force, F100 and stability parameters contributed to the lack of change in non-dominant postural sway parameters. A briefer fatigue duration than that in a previously published similar study (Paillard et al 2010) or the use of submaximal intensity contractions as compared to MVIC (Rattey et al 2006;Martin and Rattey 2007;Halperin et al 2014a) may have contributed to the lack of crossover fatigue effects.…”

“…While Rattey et al (2006) found a decrease in voluntary activation (interpolated twitch technique) and EMG of the contralateral limb but a non-significant MVIC decrease, Martin and Rattey (2007) The sway parameters (mean ± SD) calculated during the single limb standing on the fatigued and the non-fatigued limb pre-and postfatigue * Significant difference (p < 0.05) for fatigued leg pre-versus post-fatigue ** Significant difference (p < 0.05) for non-fatigued leg pre-vs. post-fatigue # The variables which were not normally distributed and analyzed using Wilcoxon rank test. The test revealed no significant results and Halperin et al (2014a) found significant reductions in both force and EMG activity in the contralateral limb. One possible reason for the lack of agreement between Rattey et al's (2006) and Halperin et al's (2014a) works and the present research may be related to the intensity of the fatiguing contraction.…”

“…One possible reason for the lack of agreement between Rattey et al's (2006) and Halperin et al's (2014a) works and the present research may be related to the intensity of the fatiguing contraction. In contrast to the aforementioned work (Rattey et al 2006;Martin and Rattey 2007;Halperin et al 2014a) that used maximal contractions, fatiguing contractions were maintained at 30 % MVIC in the present study. Crossover fatigue may depend upon the intensity at which the isometric contractions are maintained (Kennedy et al 2013) and is also thought to depend on the occurrence of central fatigue (Enoka and Duchateau 2008).…”

“…Rattey's et al (2006); Martin and Rattey (2007) and Halperin et al (2014a) used 100 s sustained MVICs of the dominant limb knee extensors to induce fatigue. While Rattey et al (2006) found a decrease in voluntary activation (interpolated twitch technique) and EMG of the contralateral limb but a non-significant MVIC decrease, Martin and Rattey (2007) The sway parameters (mean ± SD) calculated during the single limb standing on the fatigued and the non-fatigued limb pre-and postfatigue * Significant difference (p < 0.05) for fatigued leg pre-versus post-fatigue ** Significant difference (p < 0.05) for non-fatigued leg pre-vs. post-fatigue # The variables which were not normally distributed and analyzed using Wilcoxon rank test.…”

“…The effects of fatigue can either be localized or global (Rattey et al 2006). Some research has shown that local fatigue occurring in one limb can result in decreased force production in the homologous muscle (Martin and Rattey 2007;Halperin et al 2014a;Kawamoto et al 2014) as well as in heteronymous muscles (Takahashi et al 2011;Kennedy et al 2013;Halperin et al 2014b) of a non-fatigued limb. This crossover or non-local fatigue effect has been identified for upper (Humphry et al 2004;Halperin et al 2014a, b) and lower limbs (Rattey et al 2006;Martin and Rattey 2007;McLean and Samorezov 2009;Paillard et al 2010;Halperin et al 2014a, b).…”