Efficacy of Creatine Supplementation Combined with Resistance Training on Muscle Strength and Muscle Mass in Older Females: A Systematic Review and Meta-Analysis.

Sarcopenia refers to the age-related loss of muscle strength and muscle mass, which is associated with a reduced quality of life, particularly in older females. Resistance training (RT) is well established to be an effective intervention to counter indices of sarcopenia. Accumulating research indicates that the addition of creatine supplementation (Cr) to RT augments gains in muscle strength and muscle mass, compared to RT alone. However, some evidence indicates that sex differences may alter the effectiveness of Cr. Therefore, we systematically reviewed randomized controlled trials (RCTs) investigating the efficacy of Cr + RT on measures of upper- and lower-body strength and muscle mass in older females. A systematic literature search was performed in nine electronic databases. Ten RCTs (N = 211 participants) were included the review. Overall, Cr significantly increased measures of upper-body strength (7 studies, n = 142, p = 0.04), with no effect on lower-body strength or measures of muscle mass. Sub-analyses revealed that both upper-body (4 studies, n = 97, p = 0.05) and lower-body strength (4 studies, n = 100, p = 0.03) were increased by Cr, compared to placebo in studies ≥ 24 weeks in duration. In conclusion, older females supplementing with Cr experience significant gains in muscle strength, especially when RT lasts for at least 24 weeks in duration. However, given the level of evidence, future high-quality studies are needed to confirm these findings.

Associations Between Cardiorespiratory Fitness and Overweight With Academic Performance in 12-Year-Old Brazilian Children.

Obesity has been associated with poor academic achievement, while cardiorespiratory fitness (CRF) has been linked to academic success. PURPOSE: To investigate whether CRF is associated with academic performance in Brazilian students, independently of body mass index (BMI), fatness and socioeconomic status (SES). METHODS: 392 5th and 6th grade students (193 girls) (12.11 ± 0.75 years old) were evaluated in 2012. Skinfold thickness measures were performed, and students were classified according to BMI-percentile. CRF was estimated by a 20-meter shuttle run test, and academic achievement by standardized math and Portuguese tests. Multiple linear regression analyses were conducted to explore the association between academic performance and CRF, adjusted for SES, skinfold thickness or BMI-percentile. RESULTS: Among girls CRF was associated with higher academic achievement in math (ß = 0.146;p = .003) and Portuguese (ß = 0.129;p = .004) in crude and adjusted analyses. No significant association was found among boys. BMI was not associated with overall academic performance. There was a weak negative association between skinfold thickness and performance in mathematics in boys (ß =- 0.030;p = .04), but not in girls. CONCLUSION: The results highlight the importance of maintaining high fitness levels in girls throughout adolescence a period commonly associated with reductions in physical activity levels and CRF.