AUTHOR=Kelly Liam P. , Devasahayam Augustine J. , Chaves Arthur R. , Wallack Elizabeth M. , McCarthy Jason , Basset Fabien A. , Ploughman Michelle 

TITLE=Intensifying Functional Task Practice to Meet Aerobic Training Guidelines in Stroke Survivors

JOURNAL=Frontiers in Physiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00809

DOI=10.3389/fphys.2017.00809

ISSN=1664-042X

ABSTRACT=<p><bold>Objective:</bold> To determine whether stroke survivors could maintain workloads during functional task practice that can reach moderate levels of cardiometabolic stress (i.e., ≥40% oxygen uptake reserve (<inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>R) for ≥20 min) without the use of ergometer-based exercise.</p><p><bold>Design:</bold> Cross-sectional study using convenience sampling.</p><p><bold>Setting:</bold> Research laboratory in a tertiary rehabilitation hospital.</p><p><bold>Participants:</bold> Chronic hemiparetic stroke survivors (&gt;6-months) who could provide consent and walk with or without assistance.</p><p><bold>Intervention:</bold> A single bout of intermittent functional training (IFT). The IFT protocol lasted 30 min and involved performing impairment specific multi-joint task-oriented movements structured into circuits lasting ~3 min and allowing 30–45 s recovery between circuits. The aim was to achieve an average heart rate (HR) 30-50 beats above resting without using traditional ergometer-based aerobic exercise.</p><p><bold>Outcome measures:</bold> Attainment of indicators for moderate intensity aerobic exercise. Oxygen uptake (<inline-formula><mml:math id="M3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>), carbon dioxide production (<inline-formula><mml:math id="M4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>CO<sub>2</sub>), and HR were recorded throughout the 30 min IFT protocol. Values were reported as percentage of <inline-formula><mml:math id="M5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>R, HR reserve (HRR) and HRR calculated from predicted maximum HR (HRR<sub>pred</sub>), which were determined from a prior maximal graded exercise test.</p><p><bold>Results:</bold> Ten (3-female) chronic (38 ± 33 months) stroke survivors (70% ischemic) with significant residual impairments (NIHSS: 3 ± 2) and a high prevalence of comorbid conditions (80% ≥ 1) participated. IFT significantly increased all measures of exercise intensity compared to resting levels: <inline-formula><mml:math id="M6" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub> (Δ 820 ± 290 ml min<sup>−1</sup>, <italic>p</italic> &lt; 0.001), HR (Δ 42 ± 14 bpm, <italic>p</italic> &lt; 0.001), and energy expenditure (EE; Δ 4.0 ± 1.4 kcal min<sup>−1</sup>, <italic>p</italic> &lt; 0.001). Also, mean values for percentage of <inline-formula><mml:math id="M7" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>R (62 ± 19), HRR (55 ± 14), and HRR<sub>pred</sub> (52 ± 18) were significantly higher than the minimum threshold (40%) indicating achievement of moderate intensity aerobic exercise (<italic>p</italic> = 0.004, 0.016, and 0.043, respectively).</p><p><bold>Conclusion:</bold> Sufficient workloads to achieve moderate levels of cardiometabolic stress can be maintained in chronic stroke survivors using impairment-focused functional movements that are not dependent on ergometers or other specialized equipment.</p>