Table 2.
Included studies on nutritional ergogenic aids in tennis. BCAAs: Branched-chain amino acids; FFA: Blood free fatty acids; Glu: Blood glucose; Gly: Blood glycerol; HR: Heart rate; Lac: Blood lactate; LTPT: Leuven Tennis Performance Test; LTST: Loughborough Tennis Skill Test; NO; Nitric oxide; Pl: Placebo; RSA: repeated-sprint ability shuttle test; STPT: Skill Tennis Performance Test; Trp/BCAAs: Blood tryptophan/branched-chain amino acids ratio; u-EPI: Urine epinephrine; u-NE: Urine norepinephrine. ↑: Significant increase compared to placebo/control group; ↓: Significant decrease compared to placebo/control group; ↔: without changes compared to placebo/control group.
| Study | NEA | Dosage/Time | Participants | Age (yrs) | Level | Blinded/Double Blinded | Duration | Exercise Protocol | Measurements | Main Outcomes |
|---|---|---|---|---|---|---|---|---|---|---|
| [25] | Caffeine | - 0.2 (women)–0.25 (men) mg/kg/0 min before match and every 15 min during a match | 16 (8 men/8 women) | 25.4 ± 1.9/20.4 ± 2.8 | National ranking (Germany) | DB | 1 day | 3 matches (2 of 75 min/match and 1 of 90 min/match with only rest between match 2 and 3 of 30 min) + Accuracy and sprint test | - Lac | ↔ Lac |
| - Glu | ↔ Glu | |||||||||
| - Gly | ↔ Gly | |||||||||
| - FFA | ↔ FFA | |||||||||
| - u-EPI | ↑ u-EPI | |||||||||
| - u-NE | ↔ u-NE | |||||||||
| - Sprints | ↔ Sprints | |||||||||
| - Accuracy hit | ↔ Accuracy hit | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [26] | Caffeine | - 5 mg/kg/60 min before pre-test. - 0.75 mg/kg/Each 1 h after start pre-test and during protocol |
13 men | 20.4 ± 0.9 | National ranking (Belgium) | DB | 1 day | LTPT + Sprint test + Court session (120 min) + LTPT | - Sprints | ↔ Sprints |
| - Serve quality | ↔ Serve quality | |||||||||
| - Backhand stroke quality | ↑ Backhand stroke | |||||||||
| - Volley errors and fatigue | ↑ Volley errors and fatigue | |||||||||
| - HR | ↔ HR | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [27] | Caffeine | - 3 mg/kg/30 min before match | 12 men | 18.3 ± 3.0 | National ranking (Australia) | B | 1 day | 1 match of 160 min/match | - Lac | ↔ Lac |
| - Glu | ↔ Glu | |||||||||
| - CK | ↔ CK | |||||||||
| - Prolactin | ↔ Prolactin | |||||||||
| - Fluid loss | ↔ Fluid loss | |||||||||
| - Serve and stroke velocity | ↑ Serve velocity in 4th set | |||||||||
| - Serve kinematics | ↔ Serve kinematics | |||||||||
| - Perceptual skills | ↔ Perceptual skills | |||||||||
| - HR | ↔ HR | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [28] | Caffeine | - 6 mg/kg/60 min before test | 16 (8 men/8 women) | 20.7 ± 1.7 | National ranking (USA) University players (UK) |
DB | 1 day | Intermittent treadmill exercise (45 min) + Tennis skills test | - Successful shots | ↑ Total shot successes |
| - HR | ↔ HR | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [29] | Caffeine | - 80 mg/30 min before test | 12 (6 men/6 women) | 18–22 | DB | 1 day | 3 days of sleep restriction follow a day of accuracy serve test | - Accuracy serve | ↔ Accuracy serve | |
| [30] | Caffeine | - 3 mg/kg/60 min before test | 14 (10 men/4 women) | 16.4 ± 1.2 | Elite-level Junior players (Spain) | DB | 1 day | Tennis specific test + Simulated Match of best-of-3-sets system | - Handgrip force | ↑ Handgrip force |
| - Serve velocity | ↔ Serve velocity | |||||||||
| - Running speed | ↑ Only in high intensity | |||||||||
| - Number of sprints | ↑ Number of sprints | |||||||||
| - Distance | ↔ Distance | |||||||||
| - HR | ↔ HR | |||||||||
| - Sweat rate | ↑ Sweat rate | |||||||||
| [31] | Caffeine | - 6 mg/kg/60 min before test | 10 (5 men/5 women) | 19.9 ± 1.8 | National ranking (USA) | DB | 1 day | - Tennis serve trial + Shuttle run sprint + Tennis serve trial | - Accuracy serve | ↑ Accuracy serve (depending of conditions of time and distance |
| - Shuttle run time | ↔ Shuttle run time | |||||||||
| - Likert scale | ↔ Feelings | |||||||||
| [32] | Creatine | - 20 g/day (4 × 5g/day)/During 5 days before test | 8 men | 20.4 ± 0.9 | National ranking (Belgium) | DB | 5 days | LTPT + Shuttle run sprint | - Quality of 1st and 2nd service | ↔ Service quality |
| - Stroke quality | ↔ Stroke quality | |||||||||
| - Sprint power | ↔ Sprint power | |||||||||
| [33] | Creatine | - 0.3 g/kg in loading phase (6 days) - 0.03 g/day in maintenance phase (28 days) |
36 men | 22.5 ± 4.9–28.8 ± 4.8 | ITN 3 | DB | 5 weeks | - Service test + Ball machine ground stroke drill + Intermittent sprint test + Strength test | - Lac | ↔ Lac |
| - Serving velocity | ↔ Serving velocity | |||||||||
| - Stroke velocity | ↔ Stroke velocity | |||||||||
| - Sprinting velocity | ↔ Sprinting velocity | |||||||||
| - Strength | ↔ Strength | |||||||||
| - HR | ↔ HR | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [34] | Sodium Bicarbonate | - 0.3 g/kg/70 min before test - 0.1 g/kg/During test |
9 men | 21.8 ± 2.4 | College Tennis players (Taiwan) | DB | 1 day | - LTST + Simulated match (50 min) + LTST | - Lac | ↑ Lac |
| - pH | ↔ pH | |||||||||
| - Serve consistency | Keeps serve consistency while Pl ↓ | |||||||||
| - Stroke consistency | Keeps stroke consistency while Pl ↓ | |||||||||
| - Serve Accuracy | ↔ Serve Accuracy | |||||||||
| - Stroke Accuracy | ↔ Stroke Accuracy | |||||||||
| - HR | ↔ HR | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [35] | Sodium Citrate | - 0.5 g/kg/120 min before test | 10 men | 17.0 ± 1.0 | Junior National Ranking (Brazil) | DB | 1 day | STPT + RSA + Simulated match (60 min) + STPT + RSA | - Lac | ↑ Lac |
| - pH | ↑ pH | |||||||||
| - Stroke consistency | ↑ Stroke consistency | |||||||||
| - Stroke accuracy | ↔ Stroke accuracy | |||||||||
| - Number strokes | ↔ Number strokes | |||||||||
| - Time of sprints | ↔ Time of sprints | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [36] | Beetroot juice | - 70 mL (6.4 mmol of NO3−)/3 h before test | 13 men | 25.4 ± 5.1 | ATP and National ranking (Spain) | DB | 1 day | - Serve velocity test + Counter movement jump + Isometric handgrip strength + Agility and sprint test | - Serve velocity | ↔ Serve velocity |
| - Jump height | ↔ Jump height | |||||||||
| - Handgrip force | ↔ Handgrip force | |||||||||
| - Agility | ↔ Agility | |||||||||
| - Sprint velocity | ↔ Sprint velocity | |||||||||
| - Perceived exertion | ↔ Perceptual training intensity | |||||||||
| [37] | Citrulline-malate | - 8 g/60 min before test | 17 women | 51.0 ± 9.0 | Masters ranking in USTA (USA) | DB | 1 day | - Isometric handgrip strength + Counter movement jump + Wingate cycling test | - Handgrip force | ↑ Handgrip strength |
| - Peak vertical power | ↔ Jump power | |||||||||
| - Anaerobic capacity | ↔ Anaerobic capacity | |||||||||
| - Relative peak power | ↑ Relative peak power | |||||||||
| - Explosive power | ↑ Explosive power | |||||||||
| - Sustained power | ↔ Sustained power | |||||||||
| [38] | BCAAs + Arginine + Citrulline | - 0.17 g/kg BCAAs (Leu–Ile–Val = 10:7:3) + 0.05 g/kg Arginine + 0.05 g/kg Citrulline/80 min before test | 9 men | 25.6 ± 0.7 | National Ranking (Taiwan) | B | 1 day | Perceptual-motor performance test (LTST modified) + Simulated match (120 min) + Perceptual-motor performance test (LTST modified) | - Lac | ↔ Lac |
| - Gly | ↔ Gly | |||||||||
| - Glu | ↔ Glu | |||||||||
| - FFA | ↔ FFA | |||||||||
| - NO | ↑ NO | |||||||||
| - Trp/BCAAs | ↓ Trp/BCAAs | |||||||||
| - HR | ↓ HR | |||||||||
| - Stroke Accuracy | Prevents a high decrease in stroke accuracy compared with Pl | |||||||||
| - Stroke consistency | Keeps stroke consistency while Pl ↓ | |||||||||
| - Stroke velocity | Keeps stroke velocity while Pl ↓ | |||||||||
| - Perceived exertion | ↓Perceptual training intensity | |||||||||
| [39] | Glycerol | - 1 g/kg/150 min before test - 0.5 g/kg/15 min after test |
11 men | 27.0 ± 2.0 | Ranking 4–5 in USTA (USA) | DB | 1 day | Tennis specific test + Simulated match (75 min) + Tennis specific test | - Change in body | ↑ Body weight vs. Pl |
| Weight | ||||||||||
| - Plasma osmolality | ↑ Plasma osmolality vs. Pl (only pre- and post-exercise) | |||||||||
| - Change in plasma | ↑ Plasma volume vs. Pl (only pre- and post-exercise) | |||||||||
| volume | ||||||||||
| - Electrolytes | ↔ Electrolytes | |||||||||
| - Urine volume | ↓ Urine volume | |||||||||
| - Sprint velocity | ↔ Sprint velocity | |||||||||
| - Agility | ↔ Agility | |||||||||
| - Stroke accuracy | ↔ Stroke accuracy | |||||||||
| - Serve accuracy | ↔ Serve accuracy |