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. 2024 Nov;47(6):1026-1032.
doi: 10.1080/10790268.2024.2338295. Epub 2024 Apr 15.

Low-frequency electrically induced exercise after spinal cord injury: Physiologic challenge to skeletal muscle and feasibility for long-term use

Michael A Petrie  1 , Shauna Dudley-Javoroski  1 , Kristin A Johnson  1 , Jinhyun Lee  1 , Olga Dubey  1 , Richard K Shields  1
Affiliations

Low-frequency electrically induced exercise after spinal cord injury: Physiologic challenge to skeletal muscle and feasibility for long-term use

Michael A Petrie et al. J Spinal Cord Med. 2024 Nov.

Abstract

Context: Skeletal muscle has traditionally been considered a "force generator": necessary for purposes of locomotion, but expendable for non-ambulators who use wheelchairs, such as people with a spinal cord injury (SCI). Active skeletal muscle plays an indispensable role in regulating systemic metabolic functions, even in people with paralysis, but because of severe osteoporosis, high tetanic muscle forces induced with high frequency electrical stimulation may be risky for some individuals. The purpose of this study was to compare the physiologic muscle properties incurred by two low force/low frequency repetitive stimulation protocols (1 and 3 Hz); and, to assess the acceptability of each protocol among people with SCI.Methods: Ten individuals with chronic SCI (12.9 years) and 11 individuals without SCI (NonSCI) participated in the study. Participants received either 1 or 3 Hz stimulation to the quadriceps muscle on Day 1, then the converse on Day 2. Each session consisted of 1000 stimulus pulses.Results: The initial and maximum forces were similar for the 1 and 3 Hz frequencies. The fatigue index (FI) for SCI and NonSCI groups were lower (P < 0.007) for 3 Hz than for 1 Hz (0.34 ± 0.17 versus 0.65 ± 0.16 and 0.72 ± 0.14 versus 0.87 ± 0.07, respectively).Conclusion: The 3 Hz stimulation offered the greatest physiological challenge and was perceived as more acceptable for long term use among people with SCI.

Keywords: Clinical feasibility; Electrical stimulation; Metabolic disease; Precision rehabilitation.

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Figures

Figure 1
Figure 1
Representative example of twitch forces for the 1 Hz (A) and 3 Hz (B) protocols. The black traces depict the initial force and the gray traces depict the final force. Vertical lines illustrate the location of stimulus pulses. The 1 Hz protocol required 16.7 minutes to administer 1000 stimulus pulses. 1000 pulses required only 5.6 minutes for the 3 Hz protocol.
Figure 2
Figure 2
Mean (SD) muscle physiology data for the SCI and NonSCI groups for initial force (A), maximum force (B), and final force (C). *=significant difference between 1 and 3 Hz stimulation frequencies (P < 0.05). **=significant difference between SCI and NonSCI groups (P < 0.05).
Figure 3
Figure 3
Mean (SD) muscle physiology data for the SCI and NonSCI groups for force-time integral calculated from the 5 twitches used to calculate maximum force (A), time to peak force calculated from the 5 twitches used to calculate maximum force (B), and fatigue index calculated from the 5 twitches used to calculate maximum force and the 5 twitches used to calculate final force (C). *=significant difference between 1 and 3 Hz stimulation frequencies (P < 0.05). **=significant difference between SCI and NonSCI groups (P < 0.05).
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References

    1. Erickson ML, Ryan TE, Backus D, McCully KK.. Endurance neuromuscular electrical stimulation training improves skeletal muscle oxidative capacity in individuals with motor-complete spinal cord injury. Muscle Nerve 2017;55(5):669–675. PubMed PMID: 27576602; PubMed Central PMCID: 5332531. - PMC - PubMed
    1. Graham K, Yarar-Fisher C, Li J, McCully KM, Rimmer JH, Powell D, et al. . Effects of high-intensity interval training versus moderate-intensity training on cardiometabolic health markers in individuals with spinal cord injury: a pilot study. Top Spinal Cord Inj Rehabil 2019;25(3):248–259. Epub 20190516. PubMed PMID: 31548792; PubMed Central PMCID: PMC6743747. - PMC - PubMed
    1. Gorgey AS, Graham ZA, Chen Q, Rivers J, Adler RA, Lesnefsky EJ, Cardozo CP.. Sixteen weeks of testosterone with or without evoked resistance training on protein expression, fiber hypertrophy and mitochondrial health after spinal cord injury. J Appl Physiol 2020;128(6):1487–1496. Epub 20200430. PubMed PMID: 32352341. - PubMed
    1. Gorgey AS, Witt O, O'Brien L, Cardozo C, Chen Q, Lesnefsky EJ, Graham ZA.. Mitochondrial health and muscle plasticity after spinal cord injury. Eur J Appl Physiol 2019;119(2):315–331. Epub 20181211. PubMed PMID: 30539302. - PubMed
    1. Saunders LL, Clarke A, Tate DG, Forchheimer M, Krause JS.. Lifetime prevalence of chronic health conditions among persons with spinal cord injury. Archiv Phys Med Rehabil 2015;96(4):673–679. Epub 20141209. PubMed PMID: 25497516. - PubMed