The missing pieces: A systematic review of the reporting of resistance training variables in studies of pregnant women.

OBJECTIVES To examine the comprehensiveness in reporting resistance training variables among studies of pregnant women. DESIGN Systematic review. METHODS PubMed, EMBASE, CINAHL, Web of Science, and Cochrane Library were searched. All quantitative study designs were eligible if they contained any resistance training exposure during pregnancy. Studies which contained only pelvic floor muscle training, or only occupational exposure to lifting were excluded. RESULTS 117 studies from 29 countries were included (n = 66, 133 participants). Studies were assessed on the reporting of 16 resistance training variables including frequency, intensity, duration, type (exercise selection, equipment), volume (sets, repetitions, external load), pattern (rest, tempo), progressive overload, experience level, intensity measurement, pregnancy modifications, supervision, and adverse events. Supervision and frequency were well reported (87% and 79% of studies, respectively). Critical dose-related variables including sets, repetitions, intensity, and external load were poorly reported (67%, 62%, 61%, and 38% of studies, respectively). Pregnancy modifications to resistance training were reported in 65% of studies. CONCLUSIONS Key resistance training variables, including sets, repetitions, and intensity of training are not consistently reported in studies of pregnant women, precluding a strong understanding of work-rates and total training loads. To advance the field, a consensus on minimum reporting standards must be established and consistently adopted to strengthen the evidence base and enable more specific recommendations for resistance training during pregnancy. Without a comprehensive evidence-base to underpin detailed guidelines, resistance training prescription will remain conservative in research and clinical practice, limiting the potential benefits to pregnant women and their offspring.