The purpose of this study was to examine the effects of creatine supplementation during resistance training sessions on skeletal muscle mass and exercise performance in physically active young adults.
Twenty-two physically active males and females between the ages of 19-35 years old were randomized to supplement with creatine or a placebo. These were both consumed in powder form, tasting and looking the same, to ensure that participants were blind to which supplement they were taking. Creatine dosage was 0.1g per kg per day – eg: 80kg male = 8g a day, and was only taken by participants on training days.
Participants followed a 6 day resistance training program for six weeks. Day 1 was legs and core, day 2 was upper body and core, day 3 was a rest day, day 4 was legs and core, day 5 upper body, and day 6 was a rest day. This cycle was repeated for 6 weeks. No supplements were taken on the two off days.
Prior to and following training and supplementation, measurements were made for (1) muscle thickness (bicep, triceps, quadriceps, hamstrings and calf muscles), (2) power (vertical jump and medicine ball throw), (3) strength (leg press and chest press one-repetition maximum (1-RM)) and (4) muscular endurance (one set of repetitions to volitional fatigue using 50% baseline 1-RM for leg press and chest press).
Participants were excluded from the study if they were taking any medication or were followed a plant based diet.
The creatine group experienced a significant increase (p < 0.05) in leg press, chest press and total body strength and leg press endurance with no significant changes seen in the placebo group. Both groups improved total body endurance over time (p < 0.05), with greater gains observed in the creatine group. In conclusion, creatine ingestion during resistance training sessions is a viable strategy for improving muscle strength and some indices of muscle endurance in physically active young adults.
Muscle thickness:
Both groups experienced increase in body mass over time. Although there were increases in muscle thickness, there was no difference seen between the placebo or the creatine group.
Muscle performance:
Increases in overall muscular strength were seen in the creatine group, particularly in the male participant, with no improvements present in the male placebo group, or in both the groups of females. An increase in muscle endurance and repetitions was seen in the creatine group vs no change in the placebo group.
These results showed that consuming creatine on training days resulted in greater gains in muscle strength and endurance when compared to a placebo in physically active young adults. Although, this was performed on a very small cohort. Males had more of an improvement in the chest press strength when compared to females, who had no improvements. Apart from one participant experiencing GI tract discomfort during the first week of supplementation, no one else experienced any side effects. Creatine is a viable, well-tolerated method for improving muscle strength and endurance.
Reference: Mills S, Candow DG, Forbes SC, Neary JP, Ormsbee MJ, Antonio J. Effects of Creatine Supplementation during Resistance Training Sessions in Physically Active Young Adults. Nutrients. 2020 Jun 24;12(6):1880. doi: 10.3390/nu12061880. PMID: 32599716; PMCID: PMC7353308.
