Assessment of Comfort During NMES-induced Quadriceps Contractions at Two Knee Joint Angles

Bremner, Cody B; Holcomb, William R.; Brown, Christopher D.; Miller, Michael G.

doi:10.3928/19425864-20150831-03

Cited by 4 publications

(20 citation statements)

References 32 publications

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“…37 Vaz et al 38 discomfort levels is to hold either the stimulus intensity or contraction intensity constant across conditions, which has been done in other studies. 36,38,40,41 It is important to note that similar NMES-induced torque was observed across each of the conditions tested, except when applying Russian to the muscle in a relaxed state 37 ; thus it may be speculated that similar results could have been observed had the researchers standardized the contraction intensity across conditions.…”

Section: Current Parametersmentioning

confidence: 79%

“…Consequently, the authors indicated that altering the frequency from high to low frequencies, or vise-versa, may be a viable strategy to enhance NMES efficacy. These authors also observed a greater amount of time in which contractions were adequately performed while using lower frequencies (e.g., 20-30 Hz) relative to higher frequencies (e.g., [30][31][32][33][34][35][36][37][38][39][40], and this observation held true irrespective of whether the frequency was altered from low to high or high to low. Based on this observation, that lower frequencies (20-30 Hz) appeared to enhance performance irrespective of the initial frequency or fatigued state, the authors recommended using lower frequencies to delay the onset of NMES-induced fatigue; which is in agreement with some of the studies previously discussed.…”

Section: Systematically Altering Frequenciesmentioning

confidence: 94%

“…For example, while stimulating the quadriceps with a standardized stimulus intensity, self-reported comfort has been shown to significantly improve while applying NMES with the knee flexed to 60° relative to a more extended position. 36 Acclimation or habituation, which is the process by which patients become accustomed to the NMES stimulus and are able to subsequently tolerate greater amounts of current also warrants attention. Alon and Smith 144 reported that healthy participants were able to tolerate significantly greater stimulus intensities over the course of a single session consisting of 10 NMES-induced quadriceps contractions, as well as between sessions over the course of 6 days.…”

Section: Additional Comfort Strategiesmentioning

confidence: 99%

“…When discussing the influence of electrode placement on NMES-induced force production, it is important to note that while stimulating the quadriceps many of the previously discussed studies used a two electrode arrangement, 26,50,69,75,150,159 while others used an arrangement of four 36,42,44,73,145 or even three 21,27 electrodes. To the best of our knowledge there have yet to be any studies comparing which approach, if any, is best.…”

Section: Electrode Placementmentioning

confidence: 99%

“…Thus in an effort to increase NMES-induced torque, which subsequently enhances NMES training intensity, it is recommended that clinicians implement strategies with the potential to minimize fatigue and discomfort and maximize spatial recruitment. 23,24 Strategies with the potential to minimize NMES-induced fatigue [28][29][30][31][32][33][34][35] and patient discomfort [36][37][38][39][40][41] associated with NMES treatments, as well as maximizing NMES-induced torque, 26,34,39,40,[42][43][44][45] have been examined extensively. These strategies include but are not limited to: decreasing or increasing frequency, pulse duration or intensity of the electrical stimulus prior to beginning the treatment 26,[31][32][33][46][47][48][49][50][51][52][53][54][55] ; systematically altering the frequency, pulse duration or intensity over the course of the treatment 44,52,[56][57][58] ; using greater rest intervals between contractions…”

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confidence: 99%

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A Comparison of Multipath and Conventional Neuromuscular Electrical Stimulation

Bremner¹

2019

Athletic Training & Sports Health Care

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Neuromuscular electrical stimulation (NMES) is the use of an electrical current for the purpose of eliciting a muscular response, and these treatments are most often used clinically for the specific purpose of increasing quadriceps strength. It is commonly accepted that the effectiveness of NMES for this purpose is primarily determined by the NMES training intensity. However, spatially limited motor unit recruitment, fatigue and discomfort negatively impact NMES-induced torque, which subsequently reduces NMES training intensities. Due to the importance of NMES training intensity, a substantial amount of research has focused on strategies designed to increase NMES-induced torque production, as well as to reduce NMES-induced fatigue and discomfort. However, authors have indicated that additional strategies are needed, as many of the strategies supported by empirical evidence cannot be easily applied in clinical settings. The Kneehab® XP (Theragen LLC, Leesburg, VA) is an electrical stimulator that incorporates a novel multipath current distribution strategy (m-NMES) marketed to address the primary factors limiting NMES training intensity, and as such it has gained a significant amount of attention in the literature. Relative to conventional NMES (c-NMES), authors have reported improved outcomes while using the novel m-NMES but due to a series of methodological limitations the influence of the multipath current distribution strategy on these outcomes remains unclear. Therefore, the purpose of this iii project was to further investigate the influence that m-NMES has on NMES related outcomes. A convenience sample of 21 participants completed two basic studies designed to compare the influence of m-NMES and c-NMES on maximum comfortable stimulus intensity and NMES-induced peak torque, as well as fatigue and discomfort related outcomes. The statistical analyses of each study did not reveal any significant differences across the two conditions deemed to be clinically relevant. Therefore, it does not appear that the novel multipath current distribution method influences the outcomes included during this project in a clinically meaningful manner. The large declines in NMESinduced torque that occurred, irrespective of the NMES condition, suggest the need for the development of additional strategies. iv ACKNOWLEDGMENTS I would like to recognize the following individuals for their support; without each of their individual contributions this project would not have been possible. My Committee Chair and advisor Dr. Bill Holcomb. Thank you for the countless hours you spent patiently teaching and guiding me throughout my entire collegiate experience. I chose to attend USM for the opportunity to learn from you, and you exceeded my expectations. I will be forever indebted to your mentorship.

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Section: Current Parametersmentioning

confidence: 79%

Section: Systematically Altering Frequenciesmentioning

confidence: 94%

Section: Additional Comfort Strategiesmentioning

confidence: 99%

Section: Electrode Placementmentioning

confidence: 99%

mentioning

confidence: 99%

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A Comparison of Multipath and Conventional Neuromuscular Electrical Stimulation

Bremner¹

2019

Athletic Training & Sports Health Care

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Recommendations to Increase Neuromuscular Electrical Stimulation Training Intensity During Quadriceps Treatments for Orthopedic Knee Conditions

Bremner

Holcomb

Miller

2021

Clinical Journal of Sport Medicine

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Neuromuscular electrical stimulation (NMES) is often used by clinicians as a therapeutic adjunct to improve quadriceps strength deficits following orthopedic knee conditions. The efficacy of NMES treatments is primarily dependent on the NMES training intensity, which is a direct result of NMES-induced torque production. The importance of NMES training intensity is well known, yet adequate NMES training intensities are often difficult to achieve due to a variety of limitations associated with NMES (eg, fatigue and patient discomfort). This article provides recommendations that a clinician can use to increase NMES training intensity when strengthening the quadriceps with NMES for orthopedic knee conditions. These recommendations should allow forceful contractions that can be sustained over a treatment with multiple repetitions without the rapid decline in force that is typically seen when NMES is used.

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Effect of muscle length on maximum evoked torque, discomfort, contraction fatigue, and strength adaptations during electrical stimulation in adult populations: A systematic review

Cavalcante,

Ribeiro,

Marqueti

et al. 2024

PLoS ONE

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Neuromuscular electrical stimulation (NMES) can improve physical function in different populations. NMES-related outcomes may be influenced by muscle length (i.e., joint angle), a modulator of the force generation capacity of muscle fibers. Nevertheless, to date, there is no comprehensive synthesis of the available scientific evidence regarding the optimal joint angle for maximizing the effectiveness of NMES. We performed a systematic review to investigate the effect of muscle length on NMES-induced torque, discomfort, contraction fatigue, and strength training adaptations in healthy and clinical adult populations (PROSPERO: CRD42022332965). We conducted searches across seven electronic databases: PUBMED, Web of Science, EMBASE, PEDro, BIREME, SCIELO, and Cochrane, over the period from June 2022 to October 2023, without restricting the publication year. We included cross-sectional and longitudinal studies that used NMES as an intervention or assessment tool for comparing muscle lengths in adult populations. We excluded studies on vocalization, respiratory, or pelvic floor muscles. Data extraction was performed via a standardized form to gather information on participants, interventions, and outcomes. Risk of bias was assessed using the Revised Cochrane risk-of-bias tool for cross-over trials and the Physiotherapy Evidence Database scale. Out of the 1185 articles retrieved through our search strategy, we included 36 studies in our analysis, that included 448 healthy young participants (age: 19–40 years) in order to investigate maximum evoked torque (n = 268), contraction fatigability (n = 87), discomfort (n = 82), and muscle strengthening (n = 22), as well as six participants with spinal cord injuries, and 15 healthy older participants. Meta-analyses were possible for comparing maximal evoked torque according to quadriceps muscle length through knee joint angle. At optimal muscle length 50° - 70° of knee flexion, where 0° is full extension), there was greater evoked torque during nerve stimulation compared to very short (0 – 30°) (p<0.001, CI 95%: -2.03, -1.15 for muscle belly stimulation, and -3.54, -1.16 for femoral nerve stimulation), short (31° - 49°) (p = 0.007, CI 95%: -1.58, -0.25), and long (71° - 90°) (p<0.001, CI 95%: 0.29, 1.02) muscle lengths. At long muscle lengths, NMES evoked greater torque than very short (p<0.001, CI 95%: -2.50, -0.67) and short (p = 0.04, CI 95%: -2.22, -0.06) lengths. The shortest quadriceps length generated the highest perceived discomfort for a given current amplitude. The amount of contraction fatigability was greater when muscle length allowed greater torque generation in the pre-fatigue condition. Strength gains were greater for a protocol at the optimal muscle length than for short muscle length. The quality of evidence was very high for most comparisons for evoked torque. However, further studies are necessary to achieve certainty for the other outcomes. Optimal muscle length should be considered the primary choice during NMES interventions, as it promotes higher levels of force production and may facilitate the preservation/gain in muscle force and mass, with reduced discomfort. However, a longer than optimal muscle length may also be used, due to possible muscle lengthening at high evoked tension. Thorough understanding of these physiological principles is imperative for the appropriate prescription of NMES for healthy and clinical populations.

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Assessment of Comfort During NMES-induced Quadriceps Contractions at Two Knee Joint Angles

Cited by 4 publications

References 32 publications

A Comparison of Multipath and Conventional Neuromuscular Electrical Stimulation

A Comparison of Multipath and Conventional Neuromuscular Electrical Stimulation

Recommendations to Increase Neuromuscular Electrical Stimulation Training Intensity During Quadriceps Treatments for Orthopedic Knee Conditions

Effect of muscle length on maximum evoked torque, discomfort, contraction fatigue, and strength adaptations during electrical stimulation in adult populations: A systematic review

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