Reduced activation in isometric muscle action after lengthening contractions is not accompanied by reduced performance fatigability

Seiberl, Wolfgang; Hahn, Daniel; Paternoster, Florian Kurt

doi:10.1038/srep39052

Cited by 12 publications

(4 citation statements)

References 62 publications

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“…Thus, after active stretch, the same amount of torque was produced with less muscle activation. This "activation reduction" also represents a well-accepted history depended effect related to the mechanisms of rFE and was previously reported in various publications (Jones et al, 2016;Paternoster et al, 2017;Seiberl et al, 2016). In addition, the lower EMG value of GM might also underestimate the amount of rFE in session one and session three.…”

Section: Neuromuscular Aspectssupporting

confidence: 70%

Residual force enhancement in humans: Is there a true non‐responder?

et al. 2021

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When an active muscle is stretched and kept isometrically active, the resulting force is enhanced compared to a purely isometric reference contraction at the same muscle length and activity; a generally accepted muscle property called residual force enhancement (rFE). Interestingly, studies on voluntary muscle action regularly identify a significant number of participants not showing rFE. Therefore, the aim was to unmask possible confounders for this non‐responsive behavior. Ten participants performed maximum voluntary isometric plantarflexion contractions with and without preceding stretch. Contractions were accompanied by the assessment of voluntary activation using the twitch‐interpolation technique. The same test protocol was repeated four additional times with a least on day rest in‐between. Additionally, at the first and fifth sessions, a submaximal tetanic muscle‐stimulation condition was added. At both muscle‐stimulation sessions mean rFE higher 10% (p < 0.028) was found. In contrast, during voluntary muscle action, individual participants showed inconsistent rFE across sessions and only one session (#3) had significant rFE (5%; p = 0.023) in group means. As all participants clearly had rFE in electrical stimulation conditions, structural deficits cannot explain the missing rFE in voluntary muscle action. However, we also did not find variability in voluntary activation levels or muscle activity as the confounding characteristics of “non‐responders.”

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Section: Neuromuscular Aspectssupporting

confidence: 70%

Residual force enhancement in humans: Is there a true non‐responder?

et al. 2021

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“…Neuromuscular efficiency could be shown in several in vivo human studies, indicating optimized muscle function [49]. Aragão et al (2015) consider those individuals as sufficiently capable of producing greater strength with a lower magnitude of muscle activation [50].…”

Section: Mvic Rms and Quadriceps Neuromuscular Efficiencymentioning

confidence: 99%

The Influence of Hip and Knee Joint Angles on Quadriceps Muscle-Tendon Unit Properties during Maximal Voluntary Isometric Contraction

Sousa

Cavalcante

Bottaro

et al. 2023

IJERPH

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Determining how the quadriceps femoris musculotendinous unit functions, according to hip and knee joint angles, may help with clinical decisions when prescribing knee extension exercises. We aimed to determine the effect of hip and knee joint angles on structure and neuromuscular functioning of all constituents of the quadriceps femoris and patellar tendon properties. Twenty young males were evaluated in four positions: seated and supine in both 20° and 60° of knee flexion (SIT20, SIT60, SUP20, and SUP60). Peak knee extension torque was determined during maximal voluntary isometric contraction (MVIC). Ultrasound imaging was used at rest and during MVIC to characterize quadriceps femoris muscle and tendon aponeurosis complex stiffness. We found that peak torque and neuromuscular efficiency were higher for SUP60 and SIT60 compared to SUP20 and SIT20 position. We found higher fascicle length and lower pennation angle in positions with the knee flexed at 60°. The tendon aponeurosis complex stiffness, tendon force, stiffness, stress, and Young’s modulus seemed greater in more elongated positions (60°) than in shortened positions (20°). In conclusion, clinicians should consider positioning at 60° of knee flexion rather than 20°, regardless if seated or supine, during rehabilitation to load the musculotendinous unit enough to stimulate a cellular response.

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“…Therefore, much research has been conducted to evaluate the relationship between muscle activation and muscle contraction. [6][7][8]14,15 One of the most common methods to gain information about muscle is measuring electromyography signal (EMG). Nevertheless, the EMG test requires either skin-adherent or needling electrodes to acquire data, which is not suitable for monitoring muscle activities during applications in training.…”

Section: Introductionmentioning

confidence: 99%

Utilization of deep learning to classify resistance training exercises by the fabricated resistive stretch sensor

Nguyen

Chun

Kim

2023

Journal of Industrial Textiles

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In this study, the authors proposed a method to fabricate a resistive stretch textile sensor from polyester spandex (PET/SP) fabric and commercial single-walled carbon nanotube (SWCNT). In addition, we designed and trained a one-dimension convolutional neural network to classify four resistance workouts, which employed data acquired from the proposed sensor as the input. To figure out the most appropriate PET/SP sample for the deep learning application, we investigated morphologies and characterization of three samples in distinct conditions of the coating process. Data acquired from the proposed sensor illustrated the significant difference between activated and non-activated muscle groups in each specific exercise. With the PET/SP sample which met the requirements of the application, after 100 epochs, the deep learning model achieved 97.2% training accuracy and 90% test accuracy. This study demonstrates that the SWCNT-coated PET/SP stretch textile sensor can be utilized effectively to track the activity of forearm muscles during resistance training. Other than that, the proposed 1D-CNN, with the advantage of training time and computational cost, is able to classify time series data with high performance and thus can be applied widely in various deep learning applications, especially in the healthcare and sports industries.

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Reduced activation in isometric muscle action after lengthening contractions is not accompanied by reduced performance fatigability

Cited by 12 publications

References 62 publications

Residual force enhancement in humans: Is there a true non‐responder?

Residual force enhancement in humans: Is there a true non‐responder?

The Influence of Hip and Knee Joint Angles on Quadriceps Muscle-Tendon Unit Properties during Maximal Voluntary Isometric Contraction

Utilization of deep learning to classify resistance training exercises by the fabricated resistive stretch sensor

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