Is the combination of interval and resistance training more effective on physical fitness? A systematic review and Meta-analysis

Abstract Interval training (HIIT / SIT) combined with resistance training (RT) has been highlighted as a strategy for the improvement of health-related physical fitness markers (HRPF) in adults. Thus, the aim of this meta-analysis was to compare the efficacy of combined training (HIIT / SIT + RT) with other exercise protocols on HRPF markers in adults. A systematic search was performed in MEDLINE via PebMed, Cochrane-CENTRAL, SPORTDiscus, LILACS, SCIELO and Scopus databases between January and March 2017, using the following keywords in English and Portuguese: physical fitness, high-intensity interval training, sprint interval training, resistance training and adults. The quality of studies was evaluated using the PEDro scale. After applying both inclusion and exclusion criteria, nine articles were selected (n = 231). The extraction of means and standard deviations from studies was performed independently by two authors and the RevMan software was used to perform the meta-analysis. Combined training interventions lasted from 6 to 12 weeks and generated greater increase in maximal oxygen uptake than other forms of exercise. The combination of interval training and strength training may be considered more effective to improve aerobic capacity levels in adults.