Gordon McGregor 1 , 2 , * , Stuart Ennis 3 , 4 , Richard Powell 4 , Thomas Hamborg 5 , Neil T. Raymond 2 , William Owen 4 , Nicolas Aldridge 2 , Gail Evans 2 , Josie Goodby 2 , Sue Hewins 2 , Prithwish Banerjee 6 , Nithya S. Krishnan 2 , 7 , Stephen M. S. Ting 2 , 7 , Daniel Zehnder 2 , 8
11 July 2018
Exercise capacity is reduced in chronic kidney failure (CKF). Intra-dialytic cycling is beneficial, but comorbidity and fatigue can prevent this type of training. Low–frequency electrical muscle stimulation (LF-EMS) of the quadriceps and hamstrings elicits a cardiovascular training stimulus and may be a suitable alternative. The main objectives of this trial were to assess the feasibility and efficacy of intra-dialytic LF-EMS vs. cycling
Assessor blind, parallel group, randomized controlled pilot study with sixty-four stable patients on maintenance hemodialysis. Participants were randomized to 10 weeks of 1) intra-dialytic cycling, 2) intra-dialytic LF-EMS, or 3) non-exercise control. Exercise was performed for up to one hour three times per week. Cycling workload was set at 40–60% oxygen uptake (VO 2) reserve, and LF-EMS at maximum tolerable intensity. The control group did not complete any intra-dialytic exercise. Feasibility of intra-dialytic LF-EMS and cycling was the primary outcome, assessed by monitoring recruitment, retention and tolerability. At baseline and 10 weeks, secondary outcomes including cardio-respiratory reserve, muscle strength, and cardio-arterial structure and function were assessed.
Fifty-one (of 64 randomized) participants completed the study (LF-EMS = 17 [77%], cycling = 16 [80%], control = 18 [82%]). Intra-dialytic LF-EMS and cycling were feasible and well tolerated (9% and 5% intolerance respectively, P = 0.9). At 10-weeks, cardio-respiratory reserve (VO 2 peak) (Difference vs. control: LF-EMS +2.0 [95% CI, 0.3 to 3.7] ml.kg -1.min -1, P = 0.02, and cycling +3.0 [95% CI, 1.2 to 4.7] ml.kg -1.min -1, P = 0.001) and leg strength (Difference vs. control: LF-EMS, +94 [95% CI, 35.6 to 152.3] N, P = 0.002 and cycling, +65.1 [95% CI, 6.4 to 123.8] N, P = 0.002) were improved. Arterial structure and function were unaffected.