Effect of different frequencies of creatine supplementation on muscle size and strength in young adults.
Study Goal
The researchers aimed to determine if creatine supplementation, taken before and after resistance training with different dosing frequencies (2 or 3 days per week), enhances muscle size and strength gains in young adults.
Results Summary
All groups showed increased strength and muscle thickness, but creatine groups (CR2 and CR3) had greater gains in elbow flexor muscle thickness compared to placebo groups. Men on creatine experienced significantly higher leg press strength gains than women on creatine.
Population
38 physically active, non-resistance-trained university students (21-28 years old, mixed gender).
Effective Dosage
CR2: 0.15 g/kg creatine 2 days/week; CR3: 0.10 g/kg creatine 3 days/week.
Duration
6 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
resistance training | increase | strength | all groups | - | increased | #1 |
resistance training | increase | muscle thickness | all groups | - | increased | #2 |
creatine supplementation (CR2 group) | increase | muscle thickness of the elbow flexors | CR2 group | 0.6 ± 0.9 cm or 20% | experienced greater change | #3 |
creatine supplementation (CR3 group) | increase | muscle thickness of the elbow flexors | CR3 group | 0.4 ± 0.6 cm or 16.4% | experienced greater change | #4 |
placebo (PLA2 group) | increase | muscle thickness of the elbow flexors | PLA2 group | 0.05 ± 0.5 cm or 2.3% | experienced change | #5 |
placebo (PLA3 group) | increase | muscle thickness of the elbow flexors | PLA3 group | 0.13 ± 0.7 cm or 6.3% | experienced change | #6 |
creatine supplementation | increase | leg press strength | men supplementing with creatine | 77.3 ± 51.2 kg or 62% | experienced a greater increase | #7 |
creatine supplementation | increase | leg press strength | women on creatine | 21.3 ± 10 kg or 34% | experienced increase | #8 |
creatine supplementation during resistance training | increase | regional muscle thickness | young adults | - | has a small beneficial effect | #9 |
creatine supplementation | no change | effect | - | - | did not differ | #10 |
The purpose was to determine if creatine supplementation, consumed immediately before and immediately after exercise, with different dosing frequency (i.e., 2 or 3 d wk) could enhance the gains in muscle size and strength from resistance training (RT) in young adults. A group of 38 physically active, nonresistance trained university students (21-28 years) was randomly allocated to 1 of 4 groups: CR2 (0.15 g·kg creatine during 2 d wk of RT; 3 sets of 10 repetitions; n = 11, 6 men, 5 women), CR3 (0.10 g·kg creatine during 3 d wk of RT; 2 sets of 10 repetitions; n = 11, 6 men, 5 women;), PLA2 (placebo during 2 d wk of RT; n = 8, 5 men, 3 women), and PLA3 (placebo during 3 d wk of RT; n = 8, 4 men, 4 women) for 6 weeks. Before and after training, measurements were taken for muscle thickness of the elbow and knee flexor and extensor muscle groups (ultrasound), 1-repetition maximumleg press and chest press strength, and kidney function (urinary microalbumin). Repeated-measures analysis of variance showed that strength and muscle thickness increased in all groups with training (p < 0.05). The CR2 (0.6 ± 0.9 cm or 20%; p < 0.05) and CR3 groups (0.4 ± 0.6 cm or 16.4%; p < 0.05) experienced greater change in muscle thickness of the elbow flexors compared to the PLA2 (0.05 ± 0.5 cm or 2.3%) and PLA3 groups (0.13 ± 0.7 cm or 6.3%). Men supplementing with creatine experienced a greater increase in leg press strength (77.3 ± 51.2 kg or 62%) compared to women on creatine (21.3 ± 10 kg or 34%, p < 0.05). We conclude that creatine supplementation during RT has a small beneficial effect on regional muscle thickness in young adults but that giving the creatine over 3 d wk did not differ from giving the same dose over 2 d wk.