Clinimetric properties of the steep ramp test to assess cardiorespiratory fitness, its underlying physiological responses, and its current applications: a scoping review

OBJECTIVES: Providing an overview of the clinimetric properties of the steep ramp test (SRT), a short-term maximal exercise test, to assess cardiorespiratory fitness (CRF), describing its underlying physiological responses, and summarizing its applications in current clinical and research practice. DATA SOURCES: MEDLINE (through PubMed), CINAHL Complete, Cochrane Library, EMBASE, and PsychINFO, were searched for studies published up to July 2023, using keywords for SRT and CRF. STUDY SELECTION: Eligible studies involved the SRT as research subject or measurement instrument and were available as full text article in English or Dutch. DATA EXTRACTION: Two independent assessors performed data extraction. Data addressing clinimetric properties, physiological responses, and applications of the SRT were tabulated. DATA SYNTHESIS: In total, 370 studies were found, of which 39 were included in this study. In several healthy and patient populations, correlation coefficients between the work rate at peak exercise (WR ) attained at the SRT and oxygen uptake at peak exercise (V?O ) during cardiopulmonary exercise testing (CPET) ranged from 0.771 to 0.958 (criterion validity). Repeated measurements showed intraclass correlation coefficients ranging from 0.908 to 0.996 for WR attained with the first and second SRT (test-retest reliability). Physiological parameters, like heart rate and minute ventilation at peak exercise, indicated that the SRT puts a lower burden on the cardiopulmonary system compared to CPET. The SRT is mostly used to assess CRF, among others as part of preoperative risk assessment, and to personalize interval training intensity. CONCLUSIONS: The SRT is a practical short-term maximal exercise test that is valid for CRF assessment, and to monitor changes in CRF over time, in various healthy and patient populations. Its clinimetric properties and potential applications make the SRT of interest for a widespread implementation of CRF assessment in clinical and research practice, and for personalizing training intensity and monitoring longitudinal changes in CRF.