Background
Methods
Search strategy
Inclusion criteria
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Randomized, crossover, placebo-controlled and if possible blinded study design. Blinding was not feasible as an absolute criterion, as sometimes the intervention could not be fully masked;
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Mean age of the subjects between 18 and 40 years, but no restriction with respect to gender;
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A reported VO2max ≥ 50 mL/kg/min (for an appropriate estimation of subject’s fitness level);
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Assessment of body mass;
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Subjects were tested in the postprandial state (between 2 h and 4 h after ingesting last meal);
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Performance test had to be either of a time trial (TT) character or a submaximal exercise followed by a time trial (S + TT);
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For studies with carbohydrate intake immediately prior to and/or during exercise, we included only studies with provision of any type of carbohydrates, electrolytes and water but no further components.
Exclusion criteria
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Studies with time-to-exhaustion tests or studies with insufficient methodological information to enable a check of the inclusion criteria were excluded.
Categorization of interventions
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Group 1: Submaximal exercise followed by a time trial measuring time needed to cover a fixed distance or a fixed set amount of work;
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Group 2: Time trial measuring time needed to cover a fixed distance or a fixed set amount of work;
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Group 3: Submaximal exercise followed by a time trial measuring power (W) accomplished within a fixed time or distance;
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Group 4: Time trial measuring power (W) accomplished within a fixed time or distance.
Statistical analyses
Results
Literature search
Reference | Type | Test | Mode | Test time | CHO content of pre-exercise meal (g/kg body weight) | Drink type during test | Drink during test per h | |
---|---|---|---|---|---|---|---|---|
Fluid | CHO | |||||||
Acker-Hewitt et al., 2012 [38] | CHO vs. W | S + TT | Cycle | 20 min + 44 min | 1.3 | 8 % CHO not specified | 0.7 L | 56 g |
Angus et al., 2000 [44] | CHO vs. W | TT | Cycle | 166 min | 2.8 | 6 % CHO not specified | 1.0 L | 60 g |
Beelen et al., 2009 [27]a
| Mouth rinse | TT | Cycle | 68 min | 2.4 | 6.4 % MAL | 0.0 L | 0 g |
Burke et al., 2000 [25]a
| Carboloading | TT | Cycle | 148 min | 2 | Both trials same 7 % GLUP | 1.1 L | 72 g |
Burke et al., 2002 [26]a
| Carboloading | S + TT | Cycle | 120 + 25 min | 2 | Both trails same 6 % CHO, CHO not specified | 0.7 L | 44 g |
Baur et al., 2014 [39] | CHO vs. W | S + TT | Cycle | 120 + 52 min | no data | a) 12 % GLU + FRU (2:1) b) 8 % GLU c) 12 % GLU | 0.8 L | a) 93 g b) 62 g c) 93 g |
Campbell et al., 2008 [34] | CHO vs. W | S + TT | Cycle | a) 80 + 17 min b) 80 + 17 min c) 80 + 17 min | male: 1.4 female: 1.6 | All 5.9 % a) SUC + GLU + FRU drink b) MAL + FRU gel c) SUC + GLU sport beans | 0.7 L | 43 g |
Clarke et al., 2011 [30]a
| CHO vs. W | S + TT | Soccer | 90 + 3 min | no data | 6.6 % CHO not specified | 0.9 L | 59 g |
Cox et al., 2008 [35] | CHO vs. W | S + TT | Cycle | 100 min + 30 min | 2.1 | 10 % GLU | 1.125 L | 112.5 g |
Cox et al., 2010 [36] | CHO vs. W | S + TT | Cycle | 100 min + 30 min | 2.1 | 10 % GLU | 1.125 L | 112.5 g |
Desbrow et al., 2004 [45] | CHO vs. W | TT | Cycle | 63 min | 2 | 6 % CHO not specified | 1.0 L | 61 g |
El-Sayed et al., 1995 [33]a
| CHO vs. W | S + TT | Cycle | 60 + 10 min | no data | 7.5 % GLU | 0.7 L | 54 g |
El-Sayed et al., 1997 [47] | CHO vs. W | TT | Cycle | 60 min | no data | 8 % GLU | 0.3 L | 25 g |
Flynn et al., 1989 [32]a
| CHO vs. W | S + TT | Cycle | 105 + 15 min | 3.5 | 7.7 % GLUP & SUC | 0.7 L | 58 g |
Ganio et al., 2010 [31] | CHO vs. W | S + TT | Cycle | 120 + 15 min | no data | 6 % CHO not specified | 0.9 L | 53 g |
Hulston et al., 2009 [37] | CHO vs. W | S + TT | Cycle | 120 + 59 min | no data | 6 % GLU & FRU (2:1) | 0.8 L | 45 g |
Hunter et al., 2002 [46] | CHO vs. W | TT | Cycle | 150 min | no data | 7 % CHO not specified | 0.6 L | 42 g |
Jeukendrup et al., 2008 [22] | CHO vs. W | TT | Cycle | 26 min | no data | 6 % SUC & GLU (3:2) | 1.2 L | 70 g |
Langenfeld et al., 1994 [40] | CHO vs. W | TT | Cycle | 241 min | no data | 7 % MAL & FRU (5:2) | 0.5 L | 37 g |
McGawley et al., 2012 [29]a
| CHO vs. W | S + TT | Run | 88 min + 40 min | no data | 14.4 % MAL + FRU (2:1) | 0.8 L | 115 g |
Mitchell et al., 1989 [13] | CHO vs. W | S + TT | Cycle | 105 + 15 min | 0.7 | a) 6 % GLUP & SUC (2:1) b) 12 % GLUP & FRU (2.4:1) c) 18 % GLUP & FRU (4.1:1) | 0.6 L | a) 37 g b) 75 g c) 111 g |
Nassif et al., 2014 [41] | CHO vs. W | TT | Cycle | 135 min | no data | 6 % CHO not specified | 0.63 L | 38 g |
Rollo et al., 2010 [28]a
| CHO vs. W | TT | Run | 60 min | 2.5 | 6.4 % CHO not specified | 0.4 L | 28 g |
van Essen et al., 2006 [42] | CHO vs. W | TT | Cycle | 135 min | no data | 6 % SUC | 1.0 L | 60 g |
Reference | Number of subjects | Gender | Age | VO2max (mL/kg body mass/min) |
---|---|---|---|---|
Acker-Hewitt et al., 2012 [38] | 10 | Males | 28 | 66 |
Angus et al., 2000 [44] | 8 | Males | 22 | 65 |
Beelen et al., 2009 [27]a
| 14 | Males | 24 | 68 |
Burke et al., 2000 [25]a
| 7 | Males | 28 | 64 |
Burke et al., 2002 [26]a
| 8 | Males | 28 | 69 |
Baur et al., 2014 [39] | 8 | Males | 25 | 62 |
Campbell et al., 2008 [34] | 16 | 8 males/8 females | 35/32 | 59/50 |
Clarke et al., 2011 [30]a
| 12 | Males | 25 | 61 |
Cox et al., 2008 [35] | 16 | Males | 31 | 65 |
Cox et al., 2010 [36] | 16 | Males | 31 | 65 |
Desbrow et al., 2004 [45] | 9 | Males | 30 | 65 |
El-Sayed et al., 1995 [33]a
| 9 | Males | 24 | 61 |
El-Sayed et al., 1997 [47] | 8 | Males | 25 | 67 |
Flynn et al., 1989 [32]a
| 7 | Males | 29 | 62 |
Ganio et al., 2010 [31] | 14 | Males | 27 | 60 |
Hulston et al., 2009 [37] | 10 | Males | 28 | 62 |
Hunter et al., 2002 [46] | 8 | Males | 24 | 65 |
Jeukendrup et al., 2008 [22] | 12 | Males | 19 | 66 |
Langenfeld et al., 1994 [40] | 14 | Males | 21 | 56 |
McGawley et al., 2012 [29]a
| 10 | 6 males/4 females | 26/24 | 63/62 |
Mitchell et al., 1989 [13] | 10 | Males | 24 | 63 |
Nassif et al., 2014 [41] | 10 | Males | 26 | 71 |
Rollo et al., 2010 [28]a
| 10 | Males | 34 | 62 |
van Essen et al., 2006 [42] | 10 | Males | 24 | 63 |