Muscle thickness and strength adaptations in dominant and non-dominant upper limbs

Timing of creatine supplementation does not influence gains in unilateral muscle hypertrophy or strength from resistance training in young adults: a within-subject design

BACKGROUND

Creatine supplementation, in close proximity to resistance training sessions, may be an important strategy to augment muscle accretion and strength. The purpose of this study was to examine the effects of creatine supplementation immediately before compared to immediately after unilateral resistance training on hypertrophy and strength.

METHODS

Using a counter-balanced, double-blind, repeated measures within-subject design, ten recreationally active participants (7 males; 3 females; age: 23±5 years; height: 174±9 cm; body mass: 73.5±9.7 kg) were randomized to supplement with creatine monohydrate (0.1 g/kg of body mass) immediately before and placebo immediately after training one side of the body and placebo immediately before and creatine immediately after training the other side of the body on alternate days. Resistance training consisted of elbow flexion and knee extension (3-6 sets at 80% 1-repetition maximum [1-RM]) for 8 weeks. Prior to and following training, muscle thickness (elbow flexors and leg extensors; ultrasonography) and strength (1-RM for the elbow flexors and knee extensors) was assessed.

RESULTS

There was a significant increase over time for muscle thickness, strength, and relative strength (P<0.01), with no differences between creatine ingestion strategies. Total training volume performed was similar between conditions (P=0.56).

CONCLUSIONS

Creatine supplementation, immediately before or immediately after unilateral resistance training, produces similar gains in muscle hypertrophy and strength in young adults.