Ron Clemens

University of Saskatchewan, Saskatoon, Saskatchewan, Canada

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Publications (4)14.97 Total impact

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    ABSTRACT: This study compared physiological responses and work performed during a supramaximal high-intensity interval exercise training session (HIIT) and a constant work rate (CWR) exercise session. Fourteen patients with COPD (mean FEV1 % predicted (±SD)) completed an incremental cardiopulmonary exercise test (CPET) and a steep ramp anaerobic test (SRAT) and then two exercise bouts to symptom limitation on separate days, in random order: (1) a CWR trial at 80% of CPET peak work rate (mean W) and (2) a HIIT trial using repeats of 30 s at 70% of SRAT peak work rate (mean W) followed by 90 s at 20% of CPET peak work rate. Subjects ceased exercise primarily due to dyspnea for both HIIT and CWR (64% vs. 57%, resp.). End-exercise , HR, dyspnea, and leg fatigue were similar between the two exercise protocols. Average work rate was lower in HIIT than CWR (32 vs. 63 W, ); however, subjects performed HIIT longer (542 vs. 202 s, ) and for greater total work (23.3 vs. 12.0 kJ, ). The supramaximal HIIT protocol was well tolerated and demonstrated similar maximal physiologic responses to constant work rate exercise, but with greater leg muscle work performed and greater peak exercise intensity.
    No preview · Article · Oct 2013
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    ABSTRACT: The Steep Ramp Anaerobic Test (SRAT) was developed as a clinical test of anaerobic leg muscle function for use in determining anaerobic power and in prescribing high-intensity interval exercise in patients with chronic heart failure and Chronic Obstructive Pulmonary Disease (COPD); however, neither the test-retest reliability nor the physiological qualities of this test have been reported. We therefore, assessed test-retest reliability of the SRAT and the physiological characteristics associated with the test in patients with COPD. 11 COPD patients (mean FEV1 43% predicted) performed a cardiopulmonary exercise test (CPET) on Day 1, and an SRAT and a 30-second Wingate anaerobic test (WAT) on each of Days 2 and 3. The SRAT showed a high degree of test-retest reliability (ICC = 0.99; CV = 3.8%, and bias 4.5 W, error −15.3–24.4 W). Power output on the SRAT was 157 W compared to 66 W on the CPET and 231 W on the WAT. Despite the differences in workload, patients exhibited similar metabolic and ventilatory responses between the three tests. Measures of ventilatory constraint correlated more strongly with the CPET than the WAT; however, physiological variables correlated more strongly with the WAT. The SRAT is a highly reliable test that better reflects physiological performance on a WAT power test despite a similar level of ventilatory constraint compared to CPET.
    Full-text · Article · Jun 2012 · Pulmonary Medicine
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    ABSTRACT: We hypothesized that breathing helium-hyperoxia (HeO2) would significantly improve 6-min walking test (6MWT) distance in COPD subjects. This was a blinded, randomized crossover study. At visit 1, we assessed pulmonary function, exercise capacity, and 6MWT distance. Visits 2 and 3 consisted of four 6MWTs in which the following different inspired gases were used: room air (RA) by mask; 100% O2 by mask (mask O2); 100% O2 by nasal prongs (nasal O2); and 70% He/30% O2 by mask (HeO2). Walking distance, shortness of breath, leg fatigue, O2 saturation, and heart rate (HR) were assessed. Sixteen COPD subjects participated (mean FEV(1)/FVC ratio [+/- SD], 48 +/- 8%; mean FEV1, 55 +/- 13% predicted). Subjects walked farther when breathing HeO2 (564 m) compared to RA (497 m; p < 0.001), mask O2 (520 m; p < 0.001), or nasal O2 (528 m; p < 0.001). Despite the increased distance walked while breathing HeO2, there was no increase in shortness of breath or leg fatigue. There was desaturation when breathing RA (8%; p < 0.001) and nasal O2 (5%; p < 0.001), which was reduced when breathing HeO2 (3%; difference not significant) and mask O(2) (0%; difference not significant). There were no significant differences in HR in the four 6MWTs. The use of HeO2 increased 6MWT distance in COPD subjects more than either mask O2 or nasal O2 compared to RA. The increased walking distance was not associated with increased shortness of breath or leg fatigue. The results suggest that clinical benefit would be obtained by administering HeO2 during exercise, which may have significant clinical implications for the management of COPD patients.
    No preview · Article · Jun 2007 · Chest
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    ABSTRACT: To test the hypothesis that respiratory function contributes to limit maximal exercise performance in patients with chronic heart failure by using the technique of dead space loading during exercise. Blinded subjects underwent two maximal incremental exercise tests in random order on an upright bicycle ergometer: one with and one without added dead space. : Tertiary-care university teaching hospital. Seven patients with stable chronic heart failure (mean +/- SEM left ventricular ejection fraction, 27 +/- 3%). Subjects were able to significantly increase their peak minute ventilation during exercise with added dead space when compared with control exercise (57.4 +/- 5.9 vs 50.0 +/- 5.6 L/min; p < 0.05). Peak oxygen uptake, workload, heart rate, and exercise duration were not significantly different between the added dead space and control tests. Breathing pattern was significantly deeper and slower at matched levels of ventilation during exercise with added dead space. Because patients with chronic heart failure had significant ventilatory reserve at the end of exercise and were able to further increase their maximal minute ventilation, we conclude that respiratory function does not contribute to limitation of exercise in patients with chronic heart failure.
    No preview · Article · Aug 2000 · Chest

Publication Stats

34 Citations
14.97 Total Impact Points

Top Journals


  • 2012
    • University of Saskatchewan
      • Division of Respirology, Critical Care and Sleep Medicine
      Saskatoon, Saskatchewan, Canada
  • 2000
    • Royal University Hospital
      Saskatoon, Saskatchewan, Canada