The between and within day variation in gross efficiency.
Before the influence of divergent factors on gross efficiency (GE) [the ratio of mechanical power output (PO) to metabolic power input (PI)] can be assessed, the variation in GE between days, i.e. the test-retest reliability, and the within day variation needs to be known. Physically active males (n = 18) performed a maximal incremental exercise test to obtain VO2max and PO at VO2max (PVO2max), and three experimental testing days, consisting of seven submaximal exercise bouts evenly distributed over the 24 h of the day. Each submaximal exercise bout consisted of six min cycling at 45, 55 and 65% PVO2max, during which VO(2) and RER were measured. GE was determined from the final 3 min of each exercise intensity with: GE = (PO/PI) x 100%. PI was calculated by multiplying VO2 with the oxygen equivalent. GE measured during the individually highest exercise intensity with RER <1.0 did not differ significantly between days (F = 2.70, p = 0.08), which resulted in lower and upper boundaries of the 95% limits of agreement of 19.6 and 20.8%, respectively, around a mean GE of 20.2%. Although there were minor within day variations in GE, differences in GE over the day were not significant (F = 0.16, p = 0.99). The measurement of GE during cycling at intensities approximating VT is apparently very robust, a change in GE of approximately 0.6% can be reliably detected. Lastly, GE does not display a circadian rhythm so long as the criteria of a steady-state VO(2) and RER <1.0 are applied.
Noordhof
Dionne A
DA
Department of Human Movement Sciences, VU University-Amsterdam, Van Der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands. d.noordhof@fbw.vu.nl
de Koning
Jos J
JJ
van Erp
Teun
T
van Keimpema
Bart
B
de Ridder
Daan
D
Otter
Ruby
R
Foster
Carl
C
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D013647:Task Performance and Analysis
Can J Appl Physiol. 2005 Oct;30(5):520-8
16293901
Eur J Appl Physiol Occup Physiol. 1998 Feb;77(3):249-56
9535586
Med Sci Sports Exerc. 1991 Jan;23(1):93-107
1997818
Actas Esp Psiquiatr. 2008 Jan-Feb;36(1):50-9
18286400
J Sports Med Phys Fitness. 1996 Sep;36(3):155-60
8979644
J Biomech. 1990;23(9):865-81
2211732
Sports Med. 2007;37(4-5):316-9
17465597
Eur J Appl Physiol. 2005 Jan;93(4):453-62
15503124
Biophys J. 2000 Aug;79(2):945-61
10920025
Chronobiol Int. 2000 Sep;17(5):693-704
11023216
Eur J Appl Physiol. 2009 May;106(1):1-14
19229554
Sports Med. 2000 Jul;30(1):1-15
10907753
Chronobiol Int. 1990;7(1):59-67
2372852
J Appl Physiol. 1972 Sep;33(3):351-6
5056210
Int J Sports Med. 2001 Nov;22(8):553-7
11719889
Eur J Appl Physiol Occup Physiol. 1999 Nov-Dec;80(6):591-7
10541927
J Exp Biol. 2002 Apr;205(Pt 7):981-7
11916993
Chronobiol Int. 2007;24(3):495-506
17612947
Med Sci Sports Exerc. 1986 Apr;18(2):225-30
3702651
Ergonomics. 1982 May;25(5):381-6
7128568
J Appl Physiol (1985). 1991 Feb;70(2):683-7
2022559
Appl Physiol Nutr Metab. 2007 Dec;32(6):1036-42
18059575
Med Sci Sports Exerc. 1982;14(5):377-81
7154893
Med Sci Sports Exerc. 1992 Jul;24(7):782-8
1501563
Psychopharmacology (Berl). 1980;71(2):173-9
6777817
J Appl Physiol (1985). 2005 Jan;98(1):227-33
15591304
Med Sci Sports Exerc. 2008 Feb;40(2):345-50
18202566
J Appl Physiol (1985). 1991 Dec;71(6):2099-106
1778898
Chronobiologia. 1979 Oct-Dec;6(4):305-23
548245
Int J Sports Med. 2004 Jan;25(1):14-9
14750007
Med Sci Sports Exerc. 2002 Dec;34(12):2079-84
12471319
J Physiol. 2008 Jan 1;586(1):35-44
17901124
Med Sci Sports Exerc. 1996 Nov;28(11):1396-401
8933490
Med Sci Sports Exerc. 2001 Apr;33(4):621-7
11283439
Eur J Appl Physiol. 2007 Nov;101(4):465-71
17661069
Int J Chronobiol. 1976;4(2):97-110
1027738
J Appl Physiol (1985). 2009 Sep;107(3):763-9
19589952
Acta Physiol Scand. 1987 Mar;129(3):443-4
3577829
J Physiol. 2006 Mar 15;571(Pt 3):669-81
16423857
J Sci Med Sport. 1999 Oct;2(3):266-77
10668763
Sports Med. 1998 Oct;26(4):217-38
9820922