Kim Radtke

Mrs. Kim Radtke

American Association of Cardiovascular and Pulmonary Rehabilitation

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
Verified
Journal Article
Open access
PDF file
JPJohn P. Porcari
John P. Porcari
Carl FosterCarl Foster
Carl Foster
MCMaria L. Cress
Maria L. Cress
RLRachel Larson
Rachel Larson
HLHannah Lewis
Hannah Lewis
KRKim Radtke
Kim Radtke
Walking tests, such as the 6-min walk test (6MWT), are popular methods of estimating peak oxygen uptake (VO2peak) in clinical populations. However, the strength of the distance vs. VO2peak relationship is not strong, and there are no equations for estimating ventilatory threshold (VT), which is important for training prescription and prognosis. Since the 6MWT is often limited by walking mechanics, prediction equations that include simple additional predictors, such as the terminal rating of perceived exertion (RPE), hold the potential for improving the prediction of VO2max and VT. Therefore, this study was designed to develop equations for predicting VO2peak and VT from performance during the 6MWT, on the basis of walking performance and terminal RPE. Clinically stable patients in a cardiac rehabilitation program (N = 63) performed the 6MWT according to the American Thoracic Society guidelines. At the end of each walk, the subject provided their terminal RPE on a 6–20 Borg scale. Each patient also performed a maximal incremental treadmill test with respiratory gas exchange to measure VO2peak and VT. There was a good correlation between VO2peak and 6MWT distance (r = 0.80) which was improved by adding the terminal RPE in a multiple regression formula (6MWT + RPE, R2 = 0.71, standard error of estimate, SEE = 1.3 Metabolic Equivalents (METs). The VT was also well correlated with walking performance, 6MWT distance (r = 0.80), and was improved by the addition of terminal RPE (6MWT + RPE, R2 = 0.69, SEE = 0.95 METs). The addition of terminal RPE to 6MWT distance improved the prediction of maximal METs and METs at VT, which may have practical applications for exercise prescription.

Verified
Journal Article
Open access
PDF file
Carl FosterCarl Foster
Carl Foster
JAJames D. Anholm
James D. Anholm
DBDaniel Bok
Daniel Bok
Daniel A. BoullosaDaniel A. Boullosa
Daniel A. Boullosa
Giancarlo CondelloGiancarlo Condello
Giancarlo Condello
JRJose A. Rodríguez-Marroyo
Jose A. Rodríguez-Marroyo
Although there is evidence supporting the benefit of regular exercise, and recommendations about exercise and physical activity, the process of individually prescribing exercise following exercise testing is more difficult. Guidelines like % heart rate (HR) reserve (HRR) require an anchoring maximal test and do not always provide a homogenous training experience. When prescribing HR on the basis of % HRR, rating of perceived exertion or Talk Test, cardiovascular/perceptual drift during sustained exercise makes prescription of the actual workload difficult. To overcome this issue, we have demonstrated a strategy for “translating” exercise test responses to steady state exercise training on the basis of % HRR or the Talk Test that appeared adequate for individuals ranging from cardiac patients to athletes. However, these methods depended on the nature of the exercise test details. In this viewpoint, we combine these data with workload expressed as Metabolic Equivalent Task (METs). We demonstrate that there is a regular stepdown between the METs during training to achieve the same degree of homeostatic disturbance during testing. The relationship was linear, was highly-correlated (r = 0.89), and averaged 71.8% (Training METs/Test METs). We conclude that it appears possible to generate a generalized approach to correctly translate exercise test responses to exercise training.

GVGrace Vogt
Grace Vogt
KRKim Radtke
Kim Radtke
AJAndrew - Jagim
Andrew - Jagim
DPDominique Peckumn
Dominique Peckumn
TLTeresa Lee
Teresa Lee
Carl FosterCarl Foster
Carl Foster
This study examined the effects of different types of masks (no mask, surgical mask (SM), and N95-mask) on physiological and perceptual responses during 30-min of self-paced cycle ergometer exercise. This study was a prospective randomly assigned experimental design. Outcomes included workload (Watts), oxygen saturation (SpO2), end-tidal carbon dioxide (PetCO2), heart rate (HR), respiratory rate (RR), rating of perceived exertion (RPE), and rating of perceived dyspnea (RPD). Volunteers (54–83 years (n = 19)) completed two familiarization sessions and three testing sessions on an air braked cycle ergometer. No significant difference was found for condition x time for any of the dependent variables. RPE, RPD, and PetCO2 were significantly higher with an N95-mask vs. no mask (NM) ((p = 0.012), (p = 0.002), (p < 0.001)). HR was significantly higher with the SM compared to the NM condition (p = 0.027) (NM 107.18 ± 9.96) (SM 112.34 ± 10.28), but no significant difference was found when comparing the SM to the N95 condition or when comparing the N95condition to the NM condition. Watts increased across time in each condition (p = 0.003). Initially RR increased during the first 3 min of exercise (p < 0.001) with an overall gradual increase noted across time regardless of mask condition (p < 0.001). SpO2 significantly decreased across time but remained within normal limits (>95%). No significant difference was found in Watts, RR, or SpO2 regardless of mask condition. Overall, the N95mask was associated with increased RPE, RPD, and PetCO2 levels. This suggests trapping of CO2 inside the mask leading to increased RPE and RPD.

Verified
Journal Article
Open access
PDF file
KSKatrina Schultz
Katrina Schultz
Carl FosterCarl Foster
Carl Foster
KRKim Radtke
Kim Radtke
SBSusan Bramwell
Susan Bramwell
Cristina CortisCristina Cortis
Cristina Cortis
JPJohn P. Porcari
John P. Porcari
Exercise training is an important component of clinical exercise programs. Although there are recognized guidelines for the amount of exercise to be accomplished (≥70,000 steps per week or ≥150 min per week at moderate intensity), there is virtually no documentation of how much exercise is actually accomplished in contemporary exercise programs. Having guidelines without evidence of whether they are being met is of limited value. We analyzed both the weekly step count and the session rating of perceived exertion (sRPE) of patients (n = 26) enrolled in a community clinical exercise (e.g., Phase III) program over a 3-week reference period. Step counts averaged 39,818 ± 18,612 per week, with 18% of the steps accomplished in the program and 82% of steps accomplished outside the program. Using the sRPE method, inside the program, the patients averaged 162.4 ± 93.1 min per week, at a sRPE of 12.5 ± 1.9 and a frequency of 1.8 ± 0.7 times per week, for a calculated exercise load of 2042.5 ± 1244.9 AU. Outside the program, the patients averaged 144.9 ± 126.4 min, at a sRPE of 11.8 ± 5.8 and a frequency of 2.4 ± 1.5 times per week, for a calculated exercise load of 1723.9 ± 1526.2 AU. The total exercise load using sRPE was 266.4 ± 170.8 min per week, at a sRPE of 12.6 ± 3.8, and frequency of 4.2 ± 1.1 times per week, for a calculated exercise load of 3359.8 ± 2145.9 AU. There was a non-linear relationship between steps per week and the sRPE derived training load, apparently attributable to the amount of non-walking exercise accomplished in the program. The results suggest that patients in a community clinical exercise program are achieving American College of Sports Medicine guidelines, based on the sRPE method, but are accomplishing less steps than recommended by guidelines.