Pub Date : 2025-04-01Epub Date: 2025-03-08DOI: 10.1016/j.jelekin.2025.102990
Pierre Mounier , Greg Kawchuk , Arnaud Delafontaine , Jacques Abboud , Martin Descarreaux , Mégane Pasquier
This study aims to explore how Delayed Onset Muscle Soreness (DOMS) can induce changes in lumbar erector spinae neuromuscular activity, trunk kinematics and lumbar spine stiffness, and how DOMS can be confirmed as an experimental pain model for studying LBP mechanisms. Seventeen adult participants were asked to perform four sets of 25 repetitions of trunk flexion and extension. During these tasks, trunk muscle activity, spinal stiffness and kinematics were assessed. Our results suggest that in the presence of DOMS, significant increases in lumbar spine stiffness whereas only limited changes in flexion relaxation phenomenon parameters are observed.
{"title":"Delayed onset muscle soreness effect on spinal stiffness and flexion-relaxation phenomenon of the lumbar spine","authors":"Pierre Mounier , Greg Kawchuk , Arnaud Delafontaine , Jacques Abboud , Martin Descarreaux , Mégane Pasquier","doi":"10.1016/j.jelekin.2025.102990","DOIUrl":"10.1016/j.jelekin.2025.102990","url":null,"abstract":"<div><div>This study aims to explore how Delayed Onset Muscle Soreness (DOMS) can induce changes in lumbar erector spinae neuromuscular activity, trunk kinematics and lumbar spine stiffness, and how DOMS can be confirmed as an experimental pain model for studying LBP mechanisms. Seventeen adult participants were asked to perform four sets of 25 repetitions of trunk flexion and extension. During these tasks, trunk muscle activity, spinal stiffness and kinematics were assessed. Our results suggest that in the presence of DOMS, significant increases in lumbar spine stiffness whereas only limited changes in flexion relaxation phenomenon parameters are observed.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"81 ","pages":"Article 102990"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-01Epub Date: 2025-02-06DOI: 10.1016/j.jelekin.2025.102987
Simone Bettega , Lorenzo Bortolan , Federico Stella , Cantor Tarperi , Federico Schena , Barbara Pellegrini , Chiara Zoppirolli
Purpose
We examine the energetic and neuromuscular effects of running on even (E-T) and uneven terrains (UE-T) by creating smooth and rough conditions on a standardized circuit.
Methods
Ten adults (age 32.1 ± 7.6 years, body mass 62.2 ± 7 kg, height 167.5 ± 4.2 cm) ran on an ‘iterative-8-shaped’ path. For UE-T, solid hemispheres were fixed to a perforated mat, while for E-T, visible marks guided foot placement. Participants performed two 6-min trials on both terrains in a counterbalanced order, maintaining consistent running patterns and low-intensity speed with a metronome to guide step frequency. This ensured consistency in the timing and positioning of foot placement between the two conditions. Cardio-metabolic parameters were measured continuously, and muscle activation was recorded from six leg muscles using surface EMG.
Results
The analysis showed significantly higher cardio-metabolic responses in UE-T compared to E-T, with increases in oxygen cost (+18 %), energy cost (+23 %), respiratory frequency (+7%), ventilation (+19 %), heart rate (+10 %), and RPE (+50 %) (all p < 0.05). Electromyographic activation of the tibialis anterior (+22 %) and peroneus longus (+10 %) also increased in UE-T.
Conclusions
These findings indicate that running on uneven terrain demands more energy and greater activation of ankle stabilizers, as required in off-road and trail running.
{"title":"Energetic and neuromuscular impact of running on even or uneven surfaces in standardized laboratory conditions","authors":"Simone Bettega , Lorenzo Bortolan , Federico Stella , Cantor Tarperi , Federico Schena , Barbara Pellegrini , Chiara Zoppirolli","doi":"10.1016/j.jelekin.2025.102987","DOIUrl":"10.1016/j.jelekin.2025.102987","url":null,"abstract":"<div><h3>Purpose</h3><div>We examine the energetic and neuromuscular effects of running on even (E-T) and uneven terrains (UE-T) by creating smooth and rough conditions on a standardized circuit.</div></div><div><h3>Methods</h3><div>Ten adults (age 32.1 ± 7.6 years, body mass 62.2 ± 7 kg, height 167.5 ± 4.2 cm) ran on an ‘iterative-8-shaped’ path. For UE-T, solid hemispheres were fixed to a perforated mat, while for E-T, visible marks guided foot placement. Participants performed two 6-min trials on both terrains in a counterbalanced order, maintaining consistent running patterns and low-intensity speed with a metronome to guide step frequency. This ensured consistency in the timing and positioning of foot placement between the two conditions. Cardio-metabolic parameters were measured continuously, and muscle activation was recorded from six leg muscles using surface EMG.</div></div><div><h3>Results</h3><div>The analysis showed significantly higher cardio-metabolic responses in UE-T compared to E-T, with increases in oxygen cost (+18 %), energy cost (+23 %), respiratory frequency (+7%), ventilation (+19 %), heart rate (+10 %), and RPE (+50 %) (all p < 0.05). Electromyographic activation of the tibialis anterior (+22 %) and peroneus longus (+10 %) also increased in UE-T.</div></div><div><h3>Conclusions</h3><div>These findings indicate that running on uneven terrain demands more energy and greater activation of ankle stabilizers, as required in off-road and trail running.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"81 ","pages":"Article 102987"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-01Epub Date: 2025-01-23DOI: 10.1016/j.jelekin.2025.102986
Alessandro Del Vecchio, François Hug, Roberto Merletti, Dario Farina
{"title":"JEK-ISEK tutorials on electromyography and kinesiology: A summary and a call for the next series of tutorials","authors":"Alessandro Del Vecchio, François Hug, Roberto Merletti, Dario Farina","doi":"10.1016/j.jelekin.2025.102986","DOIUrl":"10.1016/j.jelekin.2025.102986","url":null,"abstract":"","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"81 ","pages":"Article 102986"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-01Epub Date: 2025-02-24DOI: 10.1016/j.jelekin.2025.102989
Mina Khajooei, Andrew Quarmby, Frank Mayer, Tilman Engel
The ability to adapt to unexpected changes in environments is associated with the risk of running-related injuries. Although gait retraining programs can mitigate injury risk, there is a scarcity of studies focusing on neuromechanical adaptations during running with unpredictable perturbations. Hence, the current experiment aimed to analyse spatial–temporal and muscle activity adaptation during a perturbed running protocol. 23 participants performed a 5-minute unperturbed and an 8-minute perturbed running trial with a baseline velocity of 2.5 m/s. During the perturbation protocol, 30-one-sided decelerative perturbations were randomly applied to both legs. Spatial-temporal data and muscle activity of twelve lower extremity and trunk muscles were recorded during unperturbed and perturbed steps. Linear mixed models with repeated measures were applied to identify adaptation at any time point in the data. Statistical analysis indicated adaptation to the perturbation trial in comparison to baseline trial for step duration, length, width and upper- and lower-leg muscles. Adaptations characterized by decreased step duration and length and increased step width and muscle activity. This study has demonstrated participants’ ability to adapt their movement and muscle activity patterns while running with unpredictable perturbations. Therefore, introducing more diverse or novel perturbation stimuli to the human system may be necessary to continually challenge adaptation.
{"title":"Neuromechanical adaptation of a perturbation protocol during treadmill running","authors":"Mina Khajooei, Andrew Quarmby, Frank Mayer, Tilman Engel","doi":"10.1016/j.jelekin.2025.102989","DOIUrl":"10.1016/j.jelekin.2025.102989","url":null,"abstract":"<div><div>The ability to adapt to unexpected changes in environments is associated with the risk of running-related injuries. Although gait retraining programs can mitigate injury risk, there is a scarcity of studies focusing on neuromechanical adaptations during running with unpredictable perturbations. Hence, the current experiment aimed to analyse spatial–temporal and muscle activity adaptation during a perturbed running protocol. 23 participants performed a 5-minute unperturbed and an 8-minute perturbed running trial with a baseline velocity of 2.5 m/s. During the perturbation protocol, 30-one-sided decelerative perturbations were randomly applied to both legs. Spatial-temporal data and muscle activity of twelve lower extremity and trunk muscles were recorded during unperturbed and perturbed steps. Linear mixed models with repeated measures were applied to identify adaptation at any time point in the data. Statistical analysis indicated adaptation to the perturbation trial in comparison to baseline trial for step duration, length, width and upper- and lower-leg muscles. Adaptations characterized by decreased step duration and length and increased step width and muscle activity. This study has demonstrated participants’ ability to adapt their movement and muscle activity patterns while running with unpredictable perturbations. Therefore, introducing more diverse or novel perturbation stimuli to the human system may be necessary to continually challenge adaptation.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"81 ","pages":"Article 102989"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-01Epub Date: 2025-01-09DOI: 10.1016/j.jelekin.2025.102975
Handan Uzunçakmak-Uyanık , Fatma Gökçem Yıldız , Ersin Tan , Çağrı Mesut Temuçin
Objectives
Jitter analysis with concentric needle electrode of the thoracic 9 (T9) paraspinal muscle (PM), where the needle EMG examination at rest is difficult, was performed in both amyotrophic lateral sclerosis (ALS) patients and the controls.
Methods
For the T9 PM, both upper limit for mean and individual mean consecutive difference (MCD) values and spike numbers were calculated according to jitter values of pairs from controls. In addition to the descriptive statistics, differences between two groups and T9 PM needle EMG and jitter analysis findings of patients were compared (p = 0.05).
Results
Mean MCD median values of T9 PM were 62.8 and 26.2 µs in patient and controls respectively. Upper limit of mean and individual MCDs for the T9 PM were determined as 36.95 μs, 57.95 μs respectively. The differences between controls and patients in terms of all jitter analysis parametres (p < 0.001) and the comparison of patients’ T9 PM needle EMG and jitter analysis findings grading were statistically significant (p = 0.029).
Conclusion
The T9 PM jitter analysis performed during routine EMG can be used to support the electrophysiological diagnosis of ALS in challenging cases and may contribute to minimizing the number of muscles examined. Furthermore, our study contributed to the T9 PM reference values for jitter analysis.
{"title":"Thoracic paraspinal muscle concentric needle electrode jitter analysis in electrophysiological diagnosis of ALS","authors":"Handan Uzunçakmak-Uyanık , Fatma Gökçem Yıldız , Ersin Tan , Çağrı Mesut Temuçin","doi":"10.1016/j.jelekin.2025.102975","DOIUrl":"10.1016/j.jelekin.2025.102975","url":null,"abstract":"<div><h3>Objectives</h3><div>Jitter analysis with concentric needle electrode of the thoracic 9 (T9) paraspinal muscle (PM), where the needle EMG examination at rest is difficult, was performed in both amyotrophic lateral sclerosis (ALS) patients and the controls.</div></div><div><h3>Methods</h3><div>For the T9 PM, both upper limit for mean and individual mean consecutive difference (MCD) values and spike numbers were calculated according to jitter values of pairs from controls. In addition to the descriptive statistics, differences between two groups and T9 PM needle EMG and jitter analysis findings of patients were compared (p = 0.05).</div></div><div><h3>Results</h3><div>Mean MCD median values of T9 PM were 62.8 and 26.2 µs in patient and controls respectively. Upper limit of mean and individual MCDs for the T9 PM were determined as 36.95 μs, 57.95 μs respectively. The differences between controls and patients in terms of all jitter analysis parametres (p < 0.001) and the comparison of patients’ T9 PM needle EMG and jitter analysis findings grading were statistically significant (p = 0.029).</div></div><div><h3>Conclusion</h3><div>The T9 PM jitter analysis performed during routine EMG can be used to support the electrophysiological diagnosis of ALS in challenging cases and may contribute to minimizing the number of muscles examined. Furthermore, our study contributed to the T9 PM reference values for jitter analysis.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"81 ","pages":"Article 102975"},"PeriodicalIF":2.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142980691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2024-12-28DOI: 10.1016/j.jelekin.2024.102973
Daniela Vlazna , Blanka Adamova , Peter Krkoska , Viktoria Kokosova , Katerina Matulova , Tamara Barusova , Michaela Sladeckova
The purpose of this cross-sectional study was to present the values of maximal isometric lumbar extensor muscle strength (MILEMS) and lumbar extensor muscle endurance (LEME) in healthy subjects and to study the influence of physiological factors on these parameters. MILEMS using a hand-held dynamometer in three positions (prone, sitting, standing) and LEME using the Biering-Sørensen test were assessed in 115 healthy volunteers. The MILEMS measurements for the specific positions were correlated with each other (Pearson correlation coefficients 0.31–0.87, p < 0.001). In univariable linear regression, sex showed the highest effect on MILEMS prediction in sitting position (higher strength in men, P < 0.001, R2 of 20.4 %). Multivariable linear regression led to construction of a calculator to estimate predicted MILEMS in the sitting position in relation to sex, age and BMI with R2 of 32.2 %. LEME was mostly predicted by BMI (decrease of LEME with increasing BMI, P < 0.001), but multivariable regression analysis did not allow the construction of a reliable calculator to predict this parameter. In conclusion, we provided values for MILEMS and LEME. A calculator was developed to predict MILEMS and to determine the percentile of measured MILEMS in an individual. It is expected to be particularly useful in assessing patients who are likely to have lumbar extensor muscle impairment.
本横断面研究的目的是了解健康受试者最大等肌伸肌力量（MILEMS）和腰伸肌耐力（LEME）的值，并研究生理因素对这些参数的影响。对115名健康志愿者进行了三种体位（俯卧、坐姿、站立）使用手持式测功机的MILEMS和使用biering - s - ørensen试验的LEME评估。特定位置的MILEMS测量结果彼此相关（Pearson相关系数为0.31-0.87，p 2为20.4%）。多变量线性回归构建了一个计算器来估计与性别、年龄和BMI相关的坐姿预测MILEMS， R2为32.2%。LEME主要由BMI预测(LEME随BMI升高而降低，P
{"title":"Strength and endurance of the lumbar extensor muscles and their predictors: A cross-sectional study in healthy subjects","authors":"Daniela Vlazna , Blanka Adamova , Peter Krkoska , Viktoria Kokosova , Katerina Matulova , Tamara Barusova , Michaela Sladeckova","doi":"10.1016/j.jelekin.2024.102973","DOIUrl":"10.1016/j.jelekin.2024.102973","url":null,"abstract":"<div><div>The purpose of this cross-sectional study was to present the values of maximal isometric lumbar extensor muscle strength (MILEMS) and lumbar extensor muscle endurance (LEME) in healthy subjects and to study the influence of physiological factors on these parameters. MILEMS using a hand-held dynamometer in three positions (prone, sitting, standing) and LEME using the Biering-Sørensen test were assessed in 115 healthy volunteers. The MILEMS measurements for the specific positions were correlated with each other (Pearson correlation coefficients 0.31–0.87, p < 0.001). In univariable linear regression, sex showed the highest effect on MILEMS prediction in sitting position (higher strength in men, P < 0.001, R<sup>2</sup> of 20.4 %). Multivariable linear regression led to construction of a calculator to estimate predicted MILEMS in the sitting position in relation to sex, age and BMI with R<sup>2</sup> of 32.2 %. LEME was mostly predicted by BMI (decrease of LEME with increasing BMI, P < 0.001), but multivariable regression analysis did not allow the construction of a reliable calculator to predict this parameter. In conclusion, we provided values for MILEMS and LEME. A calculator was developed to predict MILEMS and to determine the percentile of measured MILEMS in an individual. It is expected to be particularly useful in assessing patients who are likely to have lumbar extensor muscle impairment.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"80 ","pages":"Article 102973"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143017131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2025-01-02DOI: 10.1016/j.jelekin.2024.102974
Laura C. Marrelli , Tushar Sharma , Davis A. Forman , Giacomo G. Passarelli , Chioma Nwebube , Avery Hinks , Geoffrey A. Power , Leah R. Bent
Rate of torque development (RTD) measures how rapidly one can generate torque and is crucial for balance and athletic performance. Fast RTD depends on the rapid recruitment of high threshold motor units (MUs). Cutaneous electrical stimulation has been shown to alter MU excitability, favoring high threshold MUs via reduced recruitment thresholds. A strong coupling exists between foot sole cutaneous mechanoreceptors and motor neurons of lower-limb muscles, yet it remains unknown if cutaneous input can impact RTD via modulation of MU excitability. This study aimed to investigate whether electrical stimulation across the heel could alter plantarflexion RTD. 11 young and healthy females underwent eight sets of five explosive isometric plantarflexion contractions on a dynamometer while sitting with hip, knee and ankle angles of 80°, 110°, and 90°, respectively. All participants achieved > 95 % voluntary activation of their plantar flexors. Four sets of contractions were performed with heel cutaneous electrical stimulation (1.0 ms pulses delivered at 300 Hz, at 2 × perceptual threshold) and four sets with no stimulation. Instantaneous RTD values were analyzed in 25 ms epochs from onset to 250 ms. No significant differences were observed between stimulation conditions within each epoch, thus our results suggest that electrical cutaneous stimulation does not alter RTD in this population.
{"title":"Electrical cutaneous stimulation of the foot sole does not enhance rate of torque development during maximal effort isometric plantarflexion in females","authors":"Laura C. Marrelli , Tushar Sharma , Davis A. Forman , Giacomo G. Passarelli , Chioma Nwebube , Avery Hinks , Geoffrey A. Power , Leah R. Bent","doi":"10.1016/j.jelekin.2024.102974","DOIUrl":"10.1016/j.jelekin.2024.102974","url":null,"abstract":"<div><div>Rate of torque development (RTD) measures how rapidly one can generate torque and is crucial for balance and athletic performance. Fast RTD depends on the rapid recruitment of high threshold motor units (MUs). Cutaneous electrical stimulation has been shown to alter MU excitability, favoring high threshold MUs via reduced recruitment thresholds. A strong coupling exists between foot sole cutaneous mechanoreceptors and motor neurons of lower-limb muscles, yet it remains unknown if cutaneous input can impact RTD via modulation of MU excitability. This study aimed to investigate whether electrical stimulation across the heel could alter plantarflexion RTD. 11 young and healthy females underwent eight sets of five explosive isometric plantarflexion contractions on a dynamometer while sitting with hip, knee and ankle angles of 80°, 110°, and 90°, respectively. All participants achieved > 95 % voluntary activation of their plantar flexors. Four sets of contractions were performed with heel cutaneous electrical stimulation (1.0 ms pulses delivered at 300 Hz, at 2 × perceptual threshold) and four sets with no stimulation. Instantaneous RTD values were analyzed in 25 ms epochs from onset to 250 ms. No significant differences were observed between stimulation conditions within each epoch, thus our results suggest that electrical cutaneous stimulation does not alter RTD in this population.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"80 ","pages":"Article 102974"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142973468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2024-11-26DOI: 10.1016/j.jelekin.2024.102961
Olivia Szepietowski , Hanne Ertman , Shin-Yi Chiou , Paul H. Strutton
Background
Transcranial magnetic stimulation (TMS) has been used to assess voluntary activation (VA) of limb and back muscles, however its ability to assess abdominal muscle VA is unknown. The assessment of abdominal muscle VA using TMS could be applied to patients with trunk dysfunction to enable further understanding of the neurophysiology of trunk control, inform practice and enable the development and monitoring of rehabilitation programmes.
Aim
The aim of this study was to investigate use of TMS and the twitch interpolation technique to measure voluntary activation of abdominal muscles.
Methods
Twenty healthy participants performed sets of isometric abdominal contractions of varying levels, during which TMS was applied to the primary motor cortex. The evoked twitches were measured as torque, while simultaneous surface electromyographic (EMG) activity was recorded bilaterally from rectus abdominis, erector spinae, tensor fasciae latae, and rectus femoris. VA was calculated as: (1 – superimposed twitch amplitude/estimated resting twitch amplitude) x 100. Estimated resting twitch amplitude was calculated by extrapolation using linear regression of superimposed twitch amplitude against torque for contraction strengths 50–100 % maximum voluntary contraction (MVC).
Results
There was a strong linear relationship between voluntary torque of 50–100 % MVC and TMS-evoked twitch amplitude (r2 = 0.994, p = 0.035), and voluntary torque between 50–100 % MVC and VA (r2 = 0.997, p = 0.025). VA at a target torque of 100 % MVC was less than 100 % (86.20 ± 2.29 %).
Conclusions
VA of abdominal muscles can be assessed with twitch interpolation using TMS. VA has been shown to be submaximal during maximum voluntary contractions, and it has been demonstrated that superimposed twitch amplitude decreases in a linear fashion with increasing contraction intensity. Using this technique to explore trunk muscle function could help to improve understanding of the neurophysiology of trunk control, including the sites on any deficit in drive and also improve monitoring of the efficacy of treatment regimes for clinical conditions associated with dysfunctions in trunk control e.g. low back pain.
背景：经颅磁刺激（TMS）已被用于评估肢体和背部肌肉的自愿激活（VA），但其评估腹肌VA的能力尚不清楚。使用TMS评估腹肌VA可应用于躯干功能障碍患者，从而进一步了解躯干控制的神经生理学，为实践提供信息，并使康复方案的制定和监测成为可能。目的：本研究的目的是探讨使用经颅磁刺激和抽搐插值技术来测量腹部肌肉的随意激活。方法：20名健康参与者进行了不同程度的腹部收缩，在此期间，TMS应用于初级运动皮层。诱发抽搐以扭矩测量，同时记录双侧腹直肌、竖脊肌、阔筋膜张肌和股直肌的肌表面电图活动。VA计算为：（1 -叠加抽搐振幅/估计静息抽搐振幅）× 100。估计静息抽搐振幅通过外推法计算，使用叠加抽搐振幅与收缩强度50- 100%最大自愿收缩（MVC）扭矩的线性回归。结果：50- 100% MVC的自主转矩与tms诱发的抽搐幅度呈较强的线性关系（r2 = 0.994, p = 0.035）， 50- 100% MVC与VA的自主转矩呈较强的线性关系（r2 = 0.997, p = 0.025）。在目标扭矩为100% MVC时，VA小于100%（86.20±2.29%）。结论：经颅磁刺激可应用抽搐插值法评估腹肌VA。在最大自主收缩期间，VA已被证明是次极大的，并且已被证明，随着收缩强度的增加，叠加抽搐幅度呈线性递减。使用这项技术来探索躯干肌肉功能可以帮助我们更好地理解躯干控制的神经生理学，包括驱动缺陷的部位，也可以改善对与躯干控制功能障碍（如腰痛）相关的临床疾病治疗方案疗效的监测。
{"title":"Measurement of voluntary activation of abdominal flexors using transcranial magnetic stimulation","authors":"Olivia Szepietowski , Hanne Ertman , Shin-Yi Chiou , Paul H. Strutton","doi":"10.1016/j.jelekin.2024.102961","DOIUrl":"10.1016/j.jelekin.2024.102961","url":null,"abstract":"<div><h3>Background</h3><div>Transcranial magnetic stimulation (TMS) has been used to assess voluntary activation (VA) of limb and back muscles, however its ability to assess abdominal muscle VA is unknown. The assessment of abdominal muscle VA using TMS could be applied to patients with trunk dysfunction to enable further understanding of the neurophysiology of trunk control, inform practice and enable the development and monitoring of rehabilitation programmes.</div></div><div><h3>Aim</h3><div>The aim of this study was to investigate use of TMS and the twitch interpolation technique to measure voluntary activation of abdominal muscles.</div></div><div><h3>Methods</h3><div>Twenty healthy participants performed sets of isometric abdominal contractions of varying levels, during which TMS was applied to the primary motor cortex. The evoked twitches were measured as torque, while simultaneous surface electromyographic (EMG) activity was recorded bilaterally from rectus abdominis, erector spinae, tensor fasciae latae, and rectus femoris. VA was calculated as: (1 – superimposed twitch amplitude/estimated resting twitch amplitude) x 100. Estimated resting twitch amplitude was calculated by extrapolation using linear regression of superimposed twitch amplitude against torque for contraction strengths 50–100 % maximum voluntary contraction (MVC).</div></div><div><h3>Results</h3><div>There was a strong linear relationship between voluntary torque of 50–100 % MVC and TMS-evoked twitch amplitude (<em>r</em><sup>2</sup> = 0.994, p = 0.035), and voluntary torque between 50–100 % MVC and VA (<em>r</em><sup>2</sup> = 0.997, p = 0.025). VA at a target torque of 100 % MVC was less than 100 % (86.20 ± 2.29 %).</div></div><div><h3>Conclusions</h3><div>VA of abdominal muscles can be assessed with twitch interpolation using TMS. VA has been shown to be submaximal during maximum voluntary contractions, and it has been demonstrated that superimposed twitch amplitude decreases in a linear fashion with increasing contraction intensity. Using this technique to explore trunk muscle function could help to improve understanding of the neurophysiology of trunk control, including the sites on any deficit in drive and also improve monitoring of the efficacy of treatment regimes for clinical conditions associated with dysfunctions in trunk control e.g. low back pain.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"80 ","pages":"Article 102961"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142787805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2024-11-23DOI: 10.1016/j.jelekin.2024.102962
Raad M. Khair , Jadyn Watt , Maria Sukanen , Neil J. Cronin , Taija Finni
Although some Achilles tendon rupture (ATR) patients regain function in low-force levels activities, it is not yet well known how neuromuscular and structural alterations after ATR manifest during everyday-locomotion. This study assessed medial gastrocnemius (MG) fascicle shortening during walking 1-year after ATR. Additionally, we explored neuromuscular alterations in lateral gastrocnemius (LG), soleus and flexor hallucis longus (FHL) muscles.
We observed 3.1 pp (95 %CI 0.8–5.4 pp) higher average and 14.5 pp (95 %CI 0.5–28.5 pp) higher peak LG surface electromyography amplitude in the injured compared to the un-injured during walking, but no differences were observed in soleus or FHL. The injured limb fascicles were 12.9 mm shorter while standing compared to the un-injured limb. In absolute terms, MG shortening in the injured limb was 2.8 mm (95 %CI 0.96–4.6 mm) smaller compared to the un-injured limb. However, when normalized to standing fascicle length, the amount of shortening was not different between the limbs.
Our results showed that 1-year after ATR, MG muscle had remodelled, which manifested as shorter fascicle length during standing. During walking, injured and un-injured MG fascicles showed similar shortening relative to the standing fascicle length, suggesting that MG could function effectively at the new mechanical settings during everyday locomotion.
{"title":"Neuromechanical adaptations in the gastrocnemius muscle after Achilles tendon rupture during walking","authors":"Raad M. Khair , Jadyn Watt , Maria Sukanen , Neil J. Cronin , Taija Finni","doi":"10.1016/j.jelekin.2024.102962","DOIUrl":"10.1016/j.jelekin.2024.102962","url":null,"abstract":"<div><div>Although some Achilles tendon rupture (ATR) patients regain function in low-force levels activities, it is not yet well known how neuromuscular and structural alterations after ATR manifest during everyday-locomotion. This study assessed medial gastrocnemius (MG) fascicle shortening during walking 1-year after ATR. Additionally, we explored neuromuscular alterations in lateral gastrocnemius (LG), soleus and flexor hallucis longus (FHL) muscles.</div><div>We observed 3.1 pp (95 %CI 0.8–5.4 pp) higher average and 14.5 pp (95 %CI 0.5–28.5 pp) higher peak LG surface electromyography amplitude in the injured compared to the un-injured during walking, but no differences were observed in soleus or FHL. The injured limb fascicles were 12.9 mm shorter while standing compared to the un-injured limb. In absolute terms, MG shortening in the injured limb was 2.8 mm (95 %CI 0.96–4.6 mm) smaller compared to the un-injured limb. However, when normalized to standing fascicle length, the amount of shortening was not different between the limbs.</div><div>Our results showed that 1-year after ATR, MG muscle had remodelled, which manifested as shorter fascicle length during standing. During walking, injured and un-injured MG fascicles showed similar shortening relative to the standing fascicle length, suggesting that MG could function effectively at the new mechanical settings during everyday locomotion.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"80 ","pages":"Article 102962"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01Epub Date: 2024-12-09DOI: 10.1016/j.jelekin.2024.102966
Jacob Fanous , Charles L. Rice
Flexor hallucis longus (FHL) is an important muscle of the foot and ankle during locomotion, contributing to hallux and plantar flexion. For optimal hallux flexion the ankle needs to be stabilized against plantar flexion which may require action of the dorsiflexors. Due to the deep location of the FHL contractile drive assessed by electromyography (EMG) has not been explored systematically. Thus, the purpose was to test the relationship between the FHL and tibialis anterior (TA), the main dorsiflexor. Using indwelling EMG during isometric maximal voluntary contractions (MVC) of hallux and ankle joint actions, 10 participants (3-females, 7-males) aged 23 ± 1.4 years were tested in custom hallux-flexion and ankle dynamometers, with bipolar wire electrodes recording from the FHL, soleus and TA muscles. During MVC, forces were 169.2 ± 28.5 N, 285.5 ± 65.4 N, and 712.3 ± 313.8 N for hallux flexion, dorsiflexion, and plantar flexion, respectively. During maximal hallux flexion, TA EMG was 53 % (±26.5) of its maximum with negligible soleus activity, 4.7 % (±3.1). No significant correlations were found between TA activity and strength, foot characteristics, sex, height, weight, or soleus activity. This higher level of relative EMG recorded from the TA during maximal hallux flexion has not been observed in prior studies during walking and indicates that the relationship between the FHL and TA is task dependent, thus highlighting the important synergistic role of the TA in allowing optimal toe flexion.
{"title":"Flexor hallucis longus and tibialis anterior: A synergistic relationship","authors":"Jacob Fanous , Charles L. Rice","doi":"10.1016/j.jelekin.2024.102966","DOIUrl":"10.1016/j.jelekin.2024.102966","url":null,"abstract":"<div><div>Flexor hallucis longus (FHL) is an important muscle of the foot and ankle during locomotion, contributing to hallux and plantar flexion. For optimal hallux flexion the ankle needs to be stabilized against plantar flexion which may require action of the dorsiflexors. Due to the deep location of the FHL contractile drive assessed by electromyography (EMG) has not been explored systematically. Thus, the purpose was to test the relationship between the FHL and tibialis anterior (TA), the main dorsiflexor. Using indwelling EMG during isometric maximal voluntary contractions (MVC) of hallux and ankle joint actions, 10 participants (3-females, 7-males) aged 23 ± 1.4 years were tested in custom hallux-flexion and ankle dynamometers, with bipolar wire electrodes recording from the FHL, soleus and TA muscles. During MVC, forces were 169.2 ± 28.5 N, 285.5 ± 65.4 N, and 712.3 ± 313.8 N for hallux flexion, dorsiflexion, and plantar flexion, respectively. During maximal hallux flexion, TA EMG was 53 % (±26.5) of its maximum with negligible soleus activity, 4.7 % (±3.1). No significant correlations were found between TA activity and strength, foot characteristics, sex, height, weight, or soleus activity. This higher level of relative EMG recorded from the TA during maximal hallux flexion has not been observed in prior studies during walking and indicates that the relationship between the FHL and TA is task dependent, thus highlighting the important synergistic role of the TA in allowing optimal toe flexion.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"80 ","pages":"Article 102966"},"PeriodicalIF":2.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142840359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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