Table 4.
Studies in Model 3 investigating MPS following acute, short-term and chronic aerobic exercise or HIIT between exogenous protein and placebo/protein-free interventions
| Study (PMID) | Sex and age; years | Training status VO2max (mL/kg/min) |
Exercise intervention (mode, duration, intensity) | Muscle biopsy timepoints | Muscle subfraction(s) | Protein source | Protein amount | Co-ingested nutrients | Placebo | Main outcomes (protein vs. placebo) |
|---|---|---|---|---|---|---|---|---|---|---|
| Acute | ||||||||||
| Howarth et al. [75] (19,036,894) | M (n = 6); ~ 22 years |
Recreational NA |
HIIT cycle; 12 × 10 min; 50–80% VO2peak | 0 h, + 4 h | Mixed | Whey | 0.4 g/kg | 1.2 g/kg CHO | Low CHO: 1.2 g/kg, OR High CHO: 1.6 g/kg | ↑ 0–4 h vs. low CHO and high CHO |
| Harber et al. [66] (20,720,176) | M (n = 8); ~ 25 years | Recreational ~ 52 mL/kg/min | Cycle; 60 min; 70% VO2max | Rest, + 2 h, + 6 h | Mixed | Whey and casein | 0.37 g/kg | 0.83 g/kg/ CHO; 0.03 g/kg/fat | Non-caloric placebo | ↔ 2–6 h vs. non-caloric placebo |
| Breen et al. [55] (21,746,787) | M (n = 10); ~ 29 years | Trained ~ 66 mL/kg/min | Cycle; 90 min; 77% VO2max | 0 h, + 4 h | Myo and Mito | Whey | 20.4 g | 50.8 g CHO | 50.4 g CHO |
Myo: ↑ 0–4 h vs. 1.0 g/kg/h CHO Mito: ↔ 0–4 h vs. 1.0 g/kg/h CHO |
| Coffey et al. [56] (21,165,642) | M (n = 8); ~ 21 years | Recreational ~ 51 mL/kg/min | HIIT cycle; 10 × 6 s; maximal | Rest, + 15 min, + 4 h | Myo and Mito | Whey + Leu | 24 g whey + 4.8 g Leu | 50 g CHO | Artificial sweetener + colour |
Myo: ↑ 15 min–4 h vs. 50 g CHO Mito: ↔ 15 min–4 h vs. 50 g CHO |
| Hulston et al. [54] (21,364,482) | M (n = 8); ~ 22 years |
Trained NA |
Cycle; 180 min; 60% VO2max | Rest, 0 h, + 3 h | Mixed | Whey | 0.16 g/kg | 0.49 g/kg CHO | 0.49 g/kg CHO | ↑ 0–3 h vs. 0.49 g/kg CHO |
| Lunn et al. [57] (21,904,247) | M (n = 8); ~ 23 years |
Trained ~ 53 mL/kg/min |
Treadmill; 45 min; 65% VO2peak | Rest, 0 h, + 3 h | Mixed | Whey and casein | 16 g | CHO | 74.g CHO | ↑ 0–3 h vs. 74 g CHO |
| Andersen et al. [74] (25,411,362) | F (n = 3), M (n = 5); ~ 33 years |
Untrained NA |
One-legged kicks; 40 min; 70% VO2Max | Rest, + 3 h | Mixed | Whey and casein | 32.8 g protein | 36.6 g CHO, 1.4 g fat | Fasted | ↔ 0–3 h vs. fasted |
| Pasiakos et al. [39] (26,474,292) | F (n = 3), M (n = 37); ~ 22 years |
Recreational ~ 50 mL/kg/min |
Treadmill; 90 min; NA | Rest, + 15 min, + 195 min | Mixed; Myo; Sarco | EAA | 10 g EAA (3.6 g Leu) | 46 g CHO | 5 g CHO | Mixed; Myo; Sarco: ↔ 15 min–195 min vs. 5 g CHO |
| Rowlands et al. [59] (25,026,454) | M (n = 12); ~ 30 years |
Trained ~ 60 mL/kg/min |
HIIT cycling; 2–8 × 2 min; 70–100% Wmax | Rest; + 30 min; + 240 min | Myo | EAA | 170 g protein (15 g Leu) or 23 g protein (5 g Leu) |
180 g CHO, 30 g fat |
274 g CHO, 30 g fat | ↑ 30–240 min with both protein beverages vs. 274 g CHO, 30 g fat |
| Rundqvist et al. [60] (28,860,165) | F (n = 3), M (n = 9); ~ 26 years |
Recreational NA |
Cycling (HIIT); 3 × 30 s; maximal | 80 min; + 200 min | Mixed | EAA | 300 mg/kg bw | 1 g maltodextrin/kg | Artificial sweetener |
↔ 80–200 min vs. artificial sweetener (muscle Phe enrichment); ↑ 80–200 min vs. artificial sweetener (plasma Phe enrichment) |
| Churchward-Venne et al. [61] (32,359,142) | M (n = 48); ~ 27 years |
Trained ~ 58 mL/kg/min |
Cycling; 90 min; 60% Wmax | 0 h, + 3 h, + 6 h | Myo and Mito | Whey and casein | 15 g OR 30 g OR 45 g | 45 g CHO | 45 g CHO | Myo: ↑ 0–6 h vs. 45 g CHO; Mito: ↔ 0–6 h vs. 45 g CHO |
| Larsen et al. [62] (31,992,300) | M (n = 9); ~ 28 years |
Trained ~ 60 mL/kg/min |
Cycling; 90 min; 65% VO2peak | Pre, 0 h, + 1 h, + 4 h | Myo | WPH | 0.5 g/kg bw | 0.06 g/kg bw CHO | Flavoured water | ↔ 0–4 h vs. flavoured water |
| Short-term | ||||||||||
| Robinson et al. [63] (21,613,572) | F (n = 13), M (n = 7); ~ 50 years |
Sedentary ~ 25 mL/kg/min |
Treadmill; 30 min; 65–85% VO2 Max; 3/week; 6 weeks | Pre; + 6 weeks | Mixed | Whey and casein | 20 g | CHO | 300 kcal CHO | ↔ Post-intervention vs. 300 kcal CHO |
| Chronic | ||||||||||
| Markofski et al. [64] (29,750,251) | F (n = 30), M (n = 15); ~ 72 years |
Sedentary NA |
Walking; 40 min; NA; 24 weeks | 1 h; + 3 h | Mixed | EAA | 15 g | NA | Artificial sweetener |
↔ Post-intervention vs. artificial sweetener (basal rates of MPS); ↑ 60–180 min pre- and post-intervention in EAA + AE only |
↑ indicates significant (p < 0.05) increase post-exercise, ↔ indicates no change, + indicates post-exercise, F female, M male, Myo myofibrillar, Sarco sarcoplasmic, Mito mitochondrial, AE aerobic exercise, HIIT high-intensity interval training, Wmax maximal work load, NA not available/applicable, bw body weight, EAA essential amino acids, Leu leucine, CHO carbohydrate, WPH whey protein hydrolyte, Phe phenylalaine, MPS muscle protein synthesis, VO2max maximal oxygen uptake, VO2peak peak oxygen