Table 2 Investigation protocol for each included study.

Arngrïmsson et al., 2004 [24]

9 male, 8 female; trained

15.6 to 22.8^c

G

38

32

50

Running

Rectal

Time to complete 5 km

Booth et al., 1997 [42]

5 male, 3 female; trained

30

W

60

32

62

Running

Rectal

Distance completed in a 30-minute test at self-controlled pace

Cotter et al., 2001 [25]

9 male; untrained

35

G ± LC

45

35

60

Cycling

Rectal

Mean power output (W/kg) during 15 minutes at self-selected pace

Duffield et al., 2010 [41]

8 male; trained

40

W

20^d

33

50

Cycling

Rectal

Mean power output (W) during 40-minute time trial

Gonzalez-Alonso et al., 1999 [40]

7 male; trained

42 to 66^c

W

30

40

19

Cycling

Esophageal

Time to volitional fatigue at 60% VO₂max

Hasegawa et al., 2006 [43]

9 male; untrained

2.5 to 8.0^{e, f}

W/D/W + D

30

32

80

Cycling

Rectal

Time to volitional fatigue at 80% VO₂max

Ihsan et al., 2010 [16]

7 male; trained

70 to 103^c

I

30

30

75

Cycling

Gastrointestinal

Time to complete 40 km; mean power output (W)

Kay et al., 1999 [28]

7 male; trained

30

W

58.6

31

60

Cycling

Rectal

Distance completed in a 30-minute test at self-controlled pace

Quod et al., 2008 [27]

6 male; trained

40

G/W + G

40/70^g

34

41

Cycling

Rectal

Time to complete a fixed amount of work (kJ); mean power output (W)

Ross et al., 2011 [17]

11 male; trained

76 to 123^c

W + G/I^h

30

32 to 35

50 to 60

Cycling

Rectal

Time to complete 23 km; mean power output (W)

Siegel et al., 2010 [18]

10 male; untrained

40.7 to 50.2^c

I

30

34

55

Running

Rectal

Time to volitional fatigue at first ventilatory threshold

Siegel et al., 2012 [19]

8 male; untrained

46.7 to 56.8^c

I/W

30

34

52

Running

Rectal

Time to volitional fatigue at first ventilatory threshold

Ückert and Joch, 2007 [26]

20 male; trained

26.9 to 32.5^c

G/WU

20

30 to 32

50

Running

Tympanic

Time to volitional fatigue during an incremental treadmill test