Effects of Aquatic Exercise on Muscle Strength in Young and Elderly Adults: A Systematic Review and Meta-Analysis of Randomized Trials

ABSTRACTThe effects of training in an aquatic environment on muscular strength are still contradictory in the literature. The aim was to conduct a systematic review and meta-analysis of randomized studies about muscle strength responses after a program of aquatic exercise. A systematic review followed the Cochrane and PRISmA recommendations. The search was performed between December 2015 and January 2016. There were no language restrictions and PUBmED, SCOPUS, Scielo, Cochrane and PEDro databases were consulted. An analysis of eligibility of the studies was done by two independent authors. The data extraction followed standard criteria, and an evaluation of methodological quality was performed. The statistical analysis was conducted in Review Manager 5.1 software. The statistical heterogeneity was assessed by means of Cochran’s Q test and by the inconsistency test (I). The search found 2563 manuscripts, 27 were included, totaling a total n of 1006 participants. The analysis of the risk of bias demonstrated a lack of clarity of the randomization process, allocation concealment, blinding assessment, intention to treat analysis and calculation of the sample in 70% or more of the studies analyzed. Meta-analysis demonstrated a significant increase in handgrip strength, in isometric peak torque of knee unilateral extension and flexion and isokinetic peak torque (60°.s) of knee unilateral extension. Sensitivity analyses demonstrated that the positive effects of training in an aquatic environment may be dependent on factors such as age, velocity of movement and use of device. Land-based and aquatic exercises seem to lead to similar muscle strength gains. Aquatic exercise should be recommended as a strategy to improve muscle strength, but new studies with better methodological quality should be conducted.