Objective: This study compared the effects of different creatine supplementation dosages, independent of resistance training, on aging muscle performance and functionality.
Design and participants: Using a double-blind, repeated measures design, participants were randomized to one of three groups: Creatine-High (CR-H; n=11; 0.3 g/kg/day of creatine + 0.1 g/kg/day of maltodextrin), Creatine-Moderate (CR-M: n=11; 0.1 g/kg/day of creatine + 0.3 g/kg/day of maltodextrin) or Placebo (PLA; n=11; 0.4 g/kg/day of maltodextrin) for 10 consecutive days.
Measurements: The primary dependent variables measured at baseline and after supplementation included muscle strength (1-repetition maximum leg press, chest press, hand-grip), muscle endurance (leg press and chest press; maximal number of repetitions performed for 1 set at 80% and 70% baseline 1-repetition maximum respectively), and physical performance (dynamic balance).
Results: There was a significant increase over time for muscle strength (Leg press: CR-H pre 161.5 ± 55.1 kg, post 169.2 ± 59.2 kg; CR-M pre 145.2 ± 47.7 kg, post 151.7 ± 45.0 kg; PLA pre 163.7 ± 51.5 kg, post 178.2 ± 65.6 kg, p = 0.001; Chest press: CR-H pre 57.0 ± 26.2 kg, post 58.8 ± 28.0 kg; CR-M pre 54.5 ± 27.9 kg, post 56.8 ± 30.1 kg; PLA pre 55.1 ± 26.9 kg, post 58.5 ± 30.1 kg, p = 0.001) and endurance (Leg press: CR-H pre 17.1 ± 6.0 reps, post 21.0 ± 7.2 reps; CR-M pre 24.1 ± 11.6 reps, post 29.1 ± 17.0 reps; PLA pre 23.8 ± 9.7 reps, post 29.5 ± 11.9 reps, p = 0. 001; Chest press: CR-H pre 15.6 ± 2.7 reps, post 18.9 ± 2.7 reps; CR-M pre 18.0 ± 5.0 reps, post 19.9 ± 7.1 reps; PLA pre 20.5 ± 6.2 reps, post 21.6 ± 5.5 reps, p = 0. 001), with no other differences.
Conclusion: Short-term creatine supplementation, independent of dosage and resistance training, has no effect on aging muscle performance.
Keywords: Strength; balance; endurance; falls; resistance training.