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Background: Creatine is the most widely used supplementation to increase performance in strength; however, the most recent meta-analysis focused specifically on supplementation responses in muscles of the lower limbs without regard to upper limbs. Objective: We aimed to systematically review the effect of creatine supplementation on upper limb strength performance. Methods: We conducted a systematic review and meta-analyses of all randomized controlled trials comparing creatine supplementation with a placebo, with strength performance measured in exercises shorter than 3 min in duration. The search strategy used the keywords 'creatine', 'supplementation', and 'performance'. Independent variables were age, sex and level of physical activity at baseline, while dependent variables were creatine loading, total dose, duration, time interval between baseline (T0) and the end of the supplementation (T1), and any training during supplementation. We conducted three meta-analyses: at T0 and T1, and on changes between T0 and T1. Each meta-analysis was stratified within upper limb muscle groups. Results: We included 53 studies (563 individuals in the creatine supplementation group and 575 controls). Results did not differ at T0, while, at T1, the effect size (ES) for bench press and chest press were 0.265 (95 % CI 0.132-0.398; p < 0.001) and 0.677 (95 % CI 0.149-1.206; p = 0.012), respectively. Overall, pectoral ES was 0.289 (95 % CI 0.160-0.419; p = 0.000), and global upper limb ES was 0.317 (95 % CI 0.185-0.449; p < 0.001). Meta-analysis of changes between T0 and T1 gave similar results. The meta-regression showed no link with characteristics of population or supplementation, demonstrating the efficacy of creatine independently of all listed conditions. Conclusion: Creatine supplementation is effective in upper limb strength performance for exercise with a duration of less than 3 min, independent of population characteristics, training protocols, and supplementary doses or duration. [ABSTRACT FROM AUTHOR]

Background: Creatine is the most widely used supplementation to increase strength performance. However, the few meta-analyses are more than 10 years old and suffer from inclusion bias such as the absence of randomization and placebo, the diversity of the inclusion criteria (aerobic/endurance, anaerobic/strength), no evaluation on specific muscles or group of muscles, and the considerable amount of conflicting results within the last decade. Objective: The objective of this systematic review was to evaluate meta-analyzed effects of creatine supplementation on lower limb strength performance. Methods: We conducted a systematic review and meta-analyses of all randomized controlled trials comparing creatine supplementation with a placebo, with strength performance of the lower limbs measured in exercises lasting less than 3 min. The search strategy used the keywords 'creatine supplementation' and 'performance'. Dependent variables were creatine loading, total dose, duration, the time-intervals between baseline (T0) and the end of the supplementation (T1), as well as any training during supplementation. Independent variables were age, sex, and level of physical activity at baseline. We conducted meta-analyses at T1, and on changes between T0 and T1. Each meta-analysis was stratified within lower limb muscle groups and exercise tests. Results: We included 60 studies (646 individuals in the creatine supplementation group and 651 controls). At T1, the effect size (ES) among stratification for squat and leg press were, respectively, 0.336 (95 % CI 0.047-0.625, p = 0.023) and 0.297 (95 % CI 0.098-0.496, p = 0.003). Overall quadriceps ES was 0.266 (95 % CI 0.150-0.381, p < 0.001). Global lower limb ES was 0.235 (95 % CI 0.125-0.346, p < 0.001). Meta-analysis on changes between T0 and T1 gave similar results. The meta-regression showed no links with characteristics of population or of supplementation, demonstrating the creatine efficacy effects, independent of all listed conditions. Conclusion: Creatine supplementation is effective in lower limb strength performance for exercise with a duration of less than 3 min, independent of population characteristic, training protocols, and supplementary doses and duration. [ABSTRACT FROM AUTHOR]

We report a longitudinal survey of a 53-year-old man suffering from right knee osteoarthritis who has undergone total knee replacement (TKR). We aimed at evaluating the effect of a short preoperative isokinetic strengthening program on the functional status, pain, and quadriceps and hamstrings strength before and after TKR. The patient performed a 4-week (6 sessions) preoperative isokinetic strengthening program of the quadriceps and hamstrings. The findings for the concentric strength at 60 ∘ /s, 6-minute walk test (6MWT), and Knee injury and Osteoarthritis Outcome Score (KOOS) were recorded. At baseline the patient presented with an overall KOOS score of 44%, a 6MWT of 444 m, a 63% and 21% strength deficits of the quadriceps and hamstrings, respectively. Following the strengthening program, the quadriceps strength of the operated limb improved (+ 121 Nm; + 83%), but the function as reflected by the KOOS score remained unchanged. Following the TKR, the concentric isokinetic strength of the quadriceps reappeared altered (63% of deficit) despite pain and functional improvements. This case report underlines the importance of functional evaluation rather than the maximal strength to assess the effectiveness of TKR. However, further studies are necessary to conceptualize the meaning of maximal strength measurement and the impact of associated deficits, if any. [ABSTRACT FROM AUTHOR]