Effects of early, combined endurance and resistance training in mechanically ventilated, critically ill patients: a study protocol for a randomised controlled trial

BACKGROUND Prolonged need for intensive care is associated with neuromuscular weakness, termed Intensive Care Unit Acquired Weakness. Those affected suffer from severe functional impairment that can persist for years. First studies suggest a positive effect of physiotherapy and early mobilisation. However, the ideal intervention for a preferential functional outcome is not known. So far no randomised controlled trial has been conducted to specifically evaluate an early endurance and resistance training in the mechanically ventilated, critically ill patient. METHODS/DESIGN A randomised controlled trial with blinded assessors and 6-month follow-up will be conducted in a tertiary, interdisciplinary intensive care unit in Switzerland. Participants (n = 115; expected dropouts: n = 15) will be randomised to a control group receiving standard physiotherapy and to an experimental group that undergoes early mobilisation combined with endurance and resistance training. The inclusion criteria are being aged 18 years or older, expected mechanical ventilation for more than 72 h and qualitative independence before the illness. Primary endpoints are functional capacity (6-Minute Walk Test) and the ability to perform activities of daily living (Functional Independence Measure) measured at hospital discharge. Secondary endpoints include muscle strength (Medical Research Council sum score, handgrip strength and handheld dynamometry for quadriceps muscle), joint contractures (range of motion), exercise capacity (Timed 'Up & Go' Test) and health-related quality of life (Short Form 36). Safety will be monitored during interventions by indirect calorimetry and continuous intensive care standard monitoring. All previously defined adverse events will be noted. The statistical analysis will be by intention-to-treat with the level of significance set at p < 0.05. DISCUSSION This prospective, single-centre, allocation-concealed and assessor-blinded randomised controlled trial will evaluate participant's function after an early endurance and resistance training compared to standard care. Limitations of this study are the heterogeneity of the critically ill and the discontinuity of the protocol after relocation to the ward. The strengths lie in the pragmatic design and the clinical significance of the chosen outcome measures. TRIAL REGISTRATION German Clinical Trials Register (DRKS): DRKS00004347 , registered on 10 September 2012

HIGH INTENSITY INTERVAL EXERCISE ON BLOOD PRESSURE VARIABILITY: AGE DIFFERENCES

Saniya Waghmare1, PT, Alicen A. Whitaker-Hilbig2, DPT, PhD, Mark Chertoff1, PhD, & Sandra A. Billinger1,3, PT, PhD 1University of Kansas Medical Center, Kansas City, Kansas; 2Medical College of Wisconsin, Milwaukee, Wisconsin; 3University of Kansas Alzheimer’s Disease Research Center, Fairway, Kansas PURPOSE: With aging, studies have linked elevated beat-to-beat blood pressure variability (BTB BPV) with negative cardiovascular health. BTB BPV is a measure of the physiological autonomic nervous and cardiovascular systems interplay. The objective was to characterize mean arterial pressure BTB BPV response during high intensity interval exercise (HIIE, an exercise that repetitively switches between high intensity and active recovery) to determine the effect of aging on sympathetic nervous activity during a challenging exercise stimulus. METHODS: Secondary analysis was performed on datasets of 25 young adults, 24.96 (1.64) years of age, 48% women and 25 sedentary older adults, 60.84 (13.84) years of age, 36% women. HIIE, alternated 1-minute bouts at 70% and 10% estimated Wattmax for 10 minutes, switching between high intensity and active recovery. Maximal watts were determined using a submaximal exercise test. Blood pressure was measured using finger photoplethysmography. Raw data sampled at 500 Hz was resampled at 10 Hz to obtain beat-to-beat blood pressure. We separated high-intensity and active recovery bouts, concatenating 5 minutes of data for each intensity. Low frequency power spectral density (LF PSD) of BTB BPV was obtained by Fast Fourier transform and cross spectral density, 100-s Hanning window, 50% superposition. LF PSD, reflecting sympathetic nervous activity influence, was summed within the BTB BPV spectral range of 0.04 – 0.15 Hz. We tested normality using Shapiro Wilk test and sphericity using Mauchly’s test. The Mann-Whitney U test was used for analysis between age groups. RESULTS: LF PSD during the high-intensity bouts of HIIE for young adults was 1177.5 (662.3) mm2/Hg, and for older adults was 1274.4 (1348.2) mm2/Hg; Z = -0.84, p = 0.3. Average LF PSD during HIIE recovery for young adults was 1743.2 (1145.5) mm2/Hg, and for older adults was 1226.3 (1064.4) mm2/Hg; Z = -2.45, p \u3c 0.05. CONCLUSION: BTB BPV reflected sympathetic activity measured by LF PSD did not differ with aging during the high intensity bouts of HIIE, LF PSD reduced in older adults during the recovery bouts. Future studies should examine the relationship between reduced sympathetic activity responsiveness during HIIE and changes in vascular structures, reduced baroreflex sensitivity and adrenergic sensitivity with aging

HIIT’ING INTENSITY TARGETS: FEASIBILITY OF LOW VOLUME, SHORT INTERVAL, HIGH INTENSITY INTERVAL EXERCISE IN STROKE

Bria L. Bartsch1, Alicen A. Whitaker2, Shem Oloyede1, Saniya Waghmare1, & Sandra A. Billinger1 1University of Kansas Medical Center, Kansas City, Kansas; 2Medical College of Wisconsin, Milwaukee, Wisconsin Purpose: The recumbent stepper is ideal for stroke as it minimizes upright balance demand and offers adaptations for hemiparesis. We examined the feasibility of an acute bout of high intensity interval exercise (HIIE), performed on a recumbent stepper, in people with chronic stroke. We defined feasibility as 1) completion of exercise, 2) attainment of ≥77% heart rate max (HRmax) during high intensity intervals, and 3) no study-related cardiac or serious adverse events (SAEs). Methods: Participants between 6 months to 5 years post stroke and 40-85 years of age completed two study visits. Visit 1: A submaximal exercise test was performed to predict peak power output (PPO). Visit 2: Participants completed a 10-minute, recumbent stepper HIIE bout at 95-100 steps per minute with continuous heart rate (HR) and blood pressure (BP) monitoring. One-minute high intensity intervals (60-80% PPO) were interspersed with 1-minute active recovery intervals (10% PPO). HR and BP data were sampled at 500Hz and interpolated to 10Hz for standardization. Data were divided by R-to-R cardiac intervals, and BP was calculated for each cardiac cycle. Peak HR was extracted for each high intensity interval, and minimum HR for each active recovery interval. Data are reported as mean (standard deviation). Results: Participants (n=28) were 61% male, 61(12) years of age, 32(17) months post stroke, and 79% White and 21% African American. For HIIE, all participants completed the exercise bout, and no study-related cardiac or SAEs occurred. Average percent HRmax across all high intensity intervals reached 77(11)%, and average systolic and diastolic BP were 164(23) and 69(12) mmHg, respectively. During active recovery, average percent HRmax was 68(11)%, systolic BP was 158(24) mmHg, and diastolic BP, 66(12) mmHg. We report no serious adverse events such as orthostatic hypotension during the active recovery period. Conclusion: In chronic stroke, HIIE using the recumbent stepper was feasible with no serious adverse events. Our work provides critical data regarding HR and BP response during each cardiac cycle during HIIE and recovery, which has not been previously published and provides a strong foundation for conducting future interventional studies using HIIE on a recumbent stepper. ACKNOWLEDGEMENTS: B.L.B was supported by T32HD057850 and KUMC School of Health Professions Ph.D. Student Research Award. A.A.W. was supported by T32HL134643, T32HD057850, and American Heart Association (898190). S.O. was supported by T32AG078114 S.A.B. was supported in part by P30 AG072973

RELIABILITY OF THE TOTAL BODY RECUMBENT STEPPER SUBMAXIMAL EXERCISE TEST

David R. Wilson, Anna E. Mattlage, Abdulfattah S. Alqahtani, Nicole M. Seier, Jonathan D. Todd, Brian G. Price & Sandra A. Billinger University of Kansas Medical Center, Kansas City Kansas Submaximal exercise testing presents a practical alternative for measurement of cardio-respiratory fitness in a clinical setting where peak exercise testing my not be feasible. Previously, our lab developed a prediction equation to estimate peak VO2 using a total body recumbent stepper (TBRS) based on the Young Men’s Christian Association (YMCA) protocol. The peak VO2 prediction equation was cross-validated in a group of healthy adults and in individuals 60-80 years of age. However, we have not yet tested the reliability of the TBRS submaximal exercise test. PURPOSE: The purpose of the present study was to determine the reliability of the TBRS submaximal exercise test in healthy adults from 20-70 years of age. METHODS: A total of 40 subjects (27 M, 13 F, 39.6 yrs ± 10.3) were recruited from the Kansas City Metro and surrounding area and screened to determine eligibility. Subjects completed 2 submaximal exercise tests separated by a minimum of 24 hours and a maximum of 5 days. Testing was conducted at similar times of day. Participants were informed not to consume food or drink (except water) within 2-3 hours of the exercise tests and avoid caffeinated products for 6 hours prior to the exercise test. Participants were asked to avoid vigorous physical activity for 24 hours prior to exercise testing. Height, weight, pre-exercise HR and blood pressure (BP) were obtained prior to exercise testing. Data was analyzed using SPSS for test-retest reliability with an intraclass correlation coefficient (ICC) computation. RESULTS: We found a significant correlation between predicted peak VO2 at visit 1 and visit 2 (ICC 2,1 = 0.986, CI =.974-.993). Repeated Measures ANOVA showed no significant difference in predicted values between visits (p= 0.153). CONCLUSION: These results suggest that the TBRS submaximal exercise test and peak VO2 prediction equation can be used to reliably predict peak oxygen consumption. This is essential information for clinical professionals who want to provide their patients or clients with information regarding their cardiorespiratory fitness