Creatine Boosts Strength and Power But Benefits Vary by Age and Sex
Meta-analysis of 69 studies reveals creatine's differential effects on upper/lower body strength across populations.
Summary
A comprehensive meta-analysis of 69 studies involving 1,937 participants found that creatine supplementation significantly improves strength and power, but benefits vary dramatically by age and sex. When combined with resistance training, creatine increased bench press strength by 1.43 kg, squat strength by 5.64 kg, vertical jump by 1.48 cm, and Wingate peak power by 47.81 watts compared to placebo. However, younger adults and males showed the most consistent improvements, while older adults and females experienced smaller or non-significant changes in several measures.
Detailed Summary
This systematic review and meta-analysis represents the most comprehensive evaluation to date of creatine's effects on strength and power, analyzing 69 randomized controlled trials with 1,937 participants. The research addresses a critical gap by examining both upper and lower body outcomes together, plus muscular power assessments.
When combined with resistance training, creatine supplementation produced statistically significant but modest improvements in key compound lifts: bench/chest press strength increased by 1.43 kg (p=0.002), squat strength by 5.64 kg (p=0.001), vertical jump height by 1.48 cm (p=0.01), and Wingate peak power by 47.81 watts (p=0.004) compared to placebo. However, no significant improvements were found for handgrip strength (4.26 kg increase, p=0.10) or leg press strength (3.129 kg increase, p=0.11).
Subgroup analyses revealed striking demographic differences. Younger adults (<50 years) showed significant improvements in bench press (1.81 kg, p=0.002), leg press (8.30 kg, p=0.004), and squat strength (6.46 kg, p=0.001), while older adults showed no significant changes. Similarly, males demonstrated significant gains in leg press (9.79 kg, p=0.001), squat strength (6.43 kg, p=0.001), vertical jump (1.52 cm, p=0.04), and Wingate peak power (55.31 watts, p=0.001), but these benefits were not observed in females.
The findings suggest creatine's ergogenic effects are most pronounced in multi-joint compound exercises like squats and bench press, rather than isolated movements. The differential responses across age and sex groups highlight the need for personalized supplementation strategies and more research in underrepresented populations, particularly women and older adults.
Key Findings
- Creatine plus resistance training increased bench press strength by 1.43 kg vs placebo (p=0.002)
- Squat strength improved by 5.64 kg with creatine supplementation (p=0.001)
- Vertical jump height increased by 1.48 cm with creatine vs placebo (p=0.01)
- Wingate peak power output rose by 47.81 watts with creatine (p=0.004)
- Younger adults showed 6.46 kg greater squat strength gains vs older adults (p=0.001)
- Males demonstrated 55.31 watts greater Wingate power improvement vs females (p=0.001)
- No significant improvements found for handgrip strength (p=0.10) or leg press strength (p=0.11)
Methodology
This meta-analysis included 69 randomized controlled trials with 1,937 participants aged 18-80 years, searching PubMed, Scopus, and Web of Science through September 2024. Studies evaluated creatine supplementation effects on bench/chest press, handgrip, leg press, squat, vertical jump, and Wingate test performance. Weighted mean differences and 95% confidence intervals were calculated using random-effects modeling, with extensive subgroup analyses examining age, sex, dose, duration, and training variables.
Study Limitations
The analysis revealed high heterogeneity across studies, and approximately 95% used creatine monohydrate, limiting conclusions about other forms. The authors noted that fewer than 10 studies investigated alternative creatine forms, insufficient for robust subgroup analysis. Additionally, the differential responses across populations suggest potential confounding factors not fully captured in the available data.
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