Special relativity theory (SRT) has recently gained popularity as a first introduction to “modern” physics thinking in upper level secondary physics education. A central idea in SRT is the absolute speed of light, with light propagating with uniform speed relative to the reference frame of the observer. Previous research suggests that students, building on their prior understandings of light propagation and relative motion, develop misunderstandings of this idea. The available research provides little detail on the reasoning processes underlying these misunderstandings. We therefore studied secondary education students’ preinstructional reasoning about the speed of light in a qualitative study, probing students’ reasoning through both verbal reasoning and drawing. Event diagrams (EDs) were used as a representational tool to support student reasoning. Results show that students productively use EDs to reason with light propagation. In line with previous research, we found two alternative reference frames students could use for uniform light propagation. Most students show a flexibility in their use of reference frame: They not only evaluate light propagation in their preferred frame of reference, but also relative to other frames. Some students experienced conflict between an alternative reference frame and the speed of light and changed their reasoning because of that. This finding suggests promising directions for designing education.
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OBJECTIVE: To further test the validity and clinical usefulness of the steep ramp test (SRT) in estimating exercise tolerance in cancer survivors by external validation and extension of previously published prediction models for peak oxygen consumption (Vo2peak) and peak power output (Wpeak).DESIGN: Cross-sectional study.SETTING: Multicenter.PARTICIPANTS: Cancer survivors (N=283) in 2 randomized controlled exercise trials.INTERVENTIONS: Not applicable.MAIN OUTCOME MEASURES: Prediction model accuracy was assessed by intraclass correlation coefficients (ICCs) and limits of agreement (LOA). Multiple linear regression was used for model extension. Clinical performance was judged by the percentage of accurate endurance exercise prescriptions.RESULTS: ICCs of SRT-predicted Vo2peak and Wpeak with these values as obtained by the cardiopulmonary exercise test were .61 and .73, respectively, using the previously published prediction models. 95% LOA were ±705mL/min with a bias of 190mL/min for Vo2peak and ±59W with a bias of 5W for Wpeak. Modest improvements were obtained by adding body weight and sex to the regression equation for the prediction of Vo2peak (ICC, .73; 95% LOA, ±608mL/min) and by adding age, height, and sex for the prediction of Wpeak (ICC, .81; 95% LOA, ±48W). Accuracy of endurance exercise prescription improved from 57% accurate prescriptions to 68% accurate prescriptions with the new prediction model for Wpeak.CONCLUSIONS: Predictions of Vo2peak and Wpeak based on the SRT are adequate at the group level, but insufficiently accurate in individual patients. The multivariable prediction model for Wpeak can be used cautiously (eg, supplemented with a Borg score) to aid endurance exercise prescription.
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 (WRpeak) attained at the SRT and oxygen uptake at peak exercise (V̇O2peak) 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 WRpeak 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.
Although cardiorespiratory fitness (CRF) is being recognized as an important marker of health and functioning, it is currently not routinely assessed in daily clinical practice. There is an urgent need for a simple and feasible exercise test that can validly and reliably estimate an individual’s CRF. The Steep Ramp Test (SRT) is such a practical short-time exercise test (work rate increments of 25 W/10 seconds, so the test phase will only take up to 4 minutes) on a cycle ergometer, that does not require expensive equipment or specialized knowledge, and has been found able to validly and reliably estimate an individual’s CRF. Although the SRT is already frequently used in the Netherlands to evaluate CRF, sex- and age-specific reference values for adults and elderly are lacking thus far, which seriously limits the interpretation of test results.
