Maximal Power, but Not Fatigability, Is Greater During Repeated Sprints Performed in the Afternoon

Abstract

The present study was designed to investigate if the suggested greater fatigability during repeated exercise in the afternoon, compared to the morning, represents a true time-of-day effect on fatigability or a consequence of a higher initial power. In a counterbalanced order, eight subjects performed a repeated-sprint test [10 x (6 s of maximal cycling sprint + 30 s of rest)] on three different occasions between: 08:00-10:00, 17:00-19:00, and 17:00-19:00 h controlled (17:00-19:00 h(cont), i.e., initial power controlled to be the same as the two first sprints of the 08:00-10:00 h trial). Power output was significantly (p < 0.05) higher for sprints 1, 2, and 3 in the afternoon than in the morning (e.g., sprint 1: 23.3 +/-1 versus 21.2 +/-1 W.kg(-1)), but power decrement for the 10 sprints was also higher in the afternoon. Based on the following observations, we conclude that this higher power decrement is a consequence of the higher initial power output in the afternoon. First, there was no difference in power during the final five sprints (e.g., 20.4 +/-1 versus 19.7 +/-1 W.kg(-1) for sprint 10 in the afternoon and morning, respectively). Second, the greater decrement in the afternoon was no longer present when participants were producing the same initial power output in the afternoon as in the morning. Third, electromyographic activity of the vastus lateralis decreased during the exercise (p < 0.05), but without a time-of-day effect.

The effect of Ramadan fasting on the diurnal variations in aerobic and anaerobic performances in Tunisian youth soccer players

“…These results are consistent with those of Racinais et al (2004Racinais et al ( , 2005Racinais et al ( , 2010 who showed that muscle power is improved in the evening during the RSA test. Moreover, Souissi et al (2004Souissi et al ( , 2007 found that powers during the Wingate and the force-velocity tests fluctuate with time-of-day and reaching its maximum in the evening.…”

“…Consequently, intermittent training and testing protocols have been proposed to improve soccer players' fitness and guide talent selection (Reilly et al 2000;Impellizzeri et al 2008;Chaouachi et al 2010). In most studies, maximal single or repeated sprint performance has been observed to be higher in the afternoon than in the morning (Racinais et al 2005(Racinais et al , 2010. However, studies of the effects of time-of-day on aerobic metabolism have generally failed to report diurnal variation, especially with intensity near maximal (Dalton et al 1997;Deschenes et al 1998).…”

Is there a diurnal variation in repeated sprint ability on a non-motorised treadmill?

“…The presence of a daily variation in peak velocity in our study disagrees with previous research that reported no such differences (Hamouda et al, 2012;Souissi et al, 2008). Our findings regarding peak power are in agreement with previous research indicating significant diurnal variation in this variable (Aloui et al, 2013;Chtourou et al, 2012;Giacomoni et al, 2006;Hamouda et al, 2012;Racinais et al, 2005Racinais et al, , 2010Souissi et al, 2004Souissi et al, , 2007Souissi et al, , 2008Zarrouk et al, 2012;). However, previous findings regarding peak power are inconsistent.…”

“…Findings from these studies have consistently reported a time-of-day difference for peak power output, with higher values in the mid-afternoon or early evening when compared with the morning ($3.1% to 7.6%) for either the first or first few sprints only (Racinais et al, 2005(Racinais et al, , 2010 or for several sprints (Souissi et al, 2004(Souissi et al, , 2010. The percentage decrement in power over the repeated sprints has also been reported to show diurnal differences Racinais et al, 2005;Zarrouk et al, 2012), with higher decrements in the evening than the morning (4.0-13.1%), although some investigations have not found this result (Hamouda et al, 2012;Souissi et al, 2008).…”

The Medical Subject Headings® thesaurus remains inaccurate and incomplete for electronic indexing and retrieval of chronobiologic references

“…A striking difference from our previous study (Portaluppi 2007), was the limited consistency of ''time factors'', which identified only 32 of the 219 references (14.6%) Bougard et al 2009aBougard et al , 2009bCohen et al 2009;Danilenko et al 2009;Di Milia and Bohle 2009;Esquirol et al 2009;Jasper et al 2009;Knadler and Page 2009;Lahiri and Haldar 2009;Larsson et al 2009;Lin HC et al 2009a;Mahoney et al 2009;Minana-Solis et al 2009;Monk et al 2009;Morris et al 2009;Piccione et al 2009;Rosenberg et al 2009;Smith VM et al 2009;Suwazono et al 2009;Terrien et al 2009;van der Leest et al 2009;Vera et al 2009;Werner et al 2009;Wu et al 2009;Ayala and Hermida 2010;Clarisse et al 2010;Greubel et al 2010;Racinais et al 2010;Steinborn et al 2010;Vieira et al 2010). Moreover, using ''time factors'' to search the last 2 years of the MEDLINE with PubMed, 64,626 items were retrieved whose contents were most often unrelated to chronobiology, thus confirming the low specificity of this MeSH term for chronobiologic subjects.…”