Risk of bias and reporting practices in studies comparing VO2max responses to sprint interval vs. continuous training: A systematic review and meta-analysis

• Published in: Journal of sport and health science 2022-09, Vol.11 (5), p.552-566
• Main Authors: Bonafiglia, Jacob T., Islam, Hashim, Preobrazenski, Nicholas, Gurd, Brendon J.
• Format: Article
• Language: English
• Subjects: Bias; Cardiorespiratory fitness; CONSORT; Moderate intensity continuous training; Review; Sprint interval training
• ISSN: 2095-2546; 2213-2961; 2213-2961
• DOI: 10.1016/j.jshs.2021.03.005

•Our systematic review was the first to evaluate the risk of bias and quality of reporting in studies comparing maximal oxygen uptake responses to sprint interval training vs. moderate-intensity continuous training.•We found an overall unclear risk of bias owing to poor reporting quality in the 27 included studies. For example, only 2 studies (7%) adequately reported methods for random sequence generation, and no study reported information about allocation concealment.•This overall unclear risk of bias warrants cautious interpretation of our meta-analysis, which found, as have previously published meta-analyses, that sprint interval training and moderate-intensity continuous training similarly improve oxygen uptake. It remains unclear whether studies comparing maximal oxygen uptake (VO2max) response to sprint interval training (SIT) vs. moderate-intensity continuous training (MICT) are associated with a high risk of bias and poor reporting quality. The purpose of this study was to evaluate the risk of bias and quality of reporting in studies comparing changes in VO2max between SIT and MICT. We conducted a comprehensive literature search of 4 major databases: AMED, CINAHL, EMBASE, and MEDLINE. Studies were excluded if participants were not healthy adult humans or if training protocols were unsupervised, lasted less than 2 weeks, or utilized mixed exercise modalities. We used the Cochrane Collaboration tool and the CONSORT checklist for non-pharmacological trials to evaluate the risk of bias and reporting quality, respectively. Twenty-eight studies with 30 comparisons (3 studies included 2 SIT groups) were included in our meta-analysis (n = 360 SIT participants: body mass index (BMI) = 25.9 ± 3.7 kg/m2, baseline VO2max = 37.9 ± 8.0 mL/kg/min; n = 359 MICT participants: BMI = 25.5 ± 3.8 kg/m2; baseline VO2max = 38.3 ± 8.0 mL/kg/min; all mean ± SD). All studies had an unclear risk of bias and poor reporting quality. Although we observed a lack of superiority between SIT and MICT for improving VO2max (weighted Hedge's g = −0.004, 95% confidence interval (95%CI): −0.08 to 0.07), the overall unclear risk of bias calls the validity of this conclusion into question. Future studies using robust study designs are needed to interrogate the possibility that SIT and MICT result in similar changes in VO2max. [Display omitted]