The reliability of surface electromyography to assess quadriceps fatigue during multi joint tasks in healthy and painful knees

How Do Muscle Function and Quality Affect the Progression of KOA? A Narrative Review

Knee osteoarthritis (KOA) is widely recognized as a chronic joint disease characterized by degeneration of knee cartilage and subsequent bone hyperplasia. However, it is important to acknowledge the significant role of muscles in the development and progression of KOA. Muscle function (MF) and muscle quality (MQ) are key factors in understanding the involvement of muscles in KOA. Quantitative indices such as muscle mass, muscle strength, muscle cross-sectional area, muscle thickness, and muscle fatigue are crucial in assessing MF and MQ. Despite the growing interest in KOA, there is a scarcity of studies investigating the relationship between muscles and this condition. This review aims to examine the commonly used indices and measurement methods for assessing MF and MQ in clinical settings, while also exploring the association between muscles and KOA. Furthermore, this article highlights the importance of restoring MF and MQ to enhance symptom management and improve the quality of life for patients with KOA.

Minimal important change and difference for knee osteoarthritis outcome measurement tools after non-surgical interventions: a systematic review

OBJECTIVES

To systematically review and provide estimates of the minimal important change (MIC) and difference (MID) for outcome tools in people with knee osteoarthritis (OA) after non-surgical interventions. Design A systematic review.

DATA SOURCES

MEDLINE, CINAHL, Web of Science, Scopus and Cochrane databases were searched up to 21 September 2021.

ELIGIBILITY CRITERIA

We included studies that calculated MIC and MID using any calculation method including anchor, consensus and distribution methods, for any knee OA outcome tool after non-surgical interventions.

DATA EXTRACTION AND SYNTHESIS

We extracted reported MIC, MID and minimum detectable change (MDC) estimates. We used quality assessment tools appropriate to the studies' methods to screen out low-quality studies. Values were combined to produce a median and range, for each method.

RESULTS

Forty-eight studies were eligible (anchor-k=12, consensus-k=1 and distribution-k=35). MIC values for 13 outcome tools including Knee injury and Osteoarthritis Outcome Score (KOOS)-pain, activities of daily living (ADL), quality of life (QOL) and Western Ontario and McMaster Universities Arthritis Index (WOMAC)-function were estimated using 5 high-quality anchor studies. MID values for 23 tools including KOOS-pain, ADL, QOL and WOMAC-function, stiffness and total were estimated using 6 high-quality anchor studies. One moderate quality consensus study reported MIC for pain, function and global assessment. MDC values from distribution method estimates for 126 tools including KOOS-QOL and WOMAC-total were estimated using 38 good-to-fair-quality studies.

CONCLUSION

Median MIC, MID and MDC estimates were reported for outcome tools in people with knee OA after non-surgical interventions. The results of this review clarify the current understanding of MIC, MID and MDC in the knee OA population. However, some estimates suggest considerable heterogeneity and require careful interpretation.

PROSPERO REGISTRATION NUMBER

CRD42020215952.

Differences in Muscle Fatigability of Vastus Medialis between Sexes Using Surface Electromyographic Power Spectral Analysis in Healthy Adults

Objectives:

With a relatively high percentage of type I fibers in the vastus medialis (VM), its fatigability may be more sensitive to the effects of muscle activity in the quadriceps. However, sex-related differences in the muscle fatigability of the VM remain unknown. The purpose of the present study was to assess the differences in fatigability of the VM between healthy adult men and women.

Methods:

Surface electromyographic (EMG) activities of VM oblique (VMO) and VM long (VML) were recorded during sustained isometric contraction on a leg press machine. The results of EMG power spectral analysis were compared between healthy adult men and women. The decline in the median frequency (MF), defined as MF slope, was calculated using spectrum analysis after fast Fourier transform of the raw EMG signals of VMO and VML.

Results:

The endurance time and the MF slopes of the VMO and VML were significantly longer and lower, respectively, in women than in men. The present results demonstrated that both VMO and VML are more fatigue-resistant in women than in men.

Conclusions:

Understanding the sex differences in fatigability could help to design more effective exercise regimens for VMO and VML in healthy individuals. A similar approach should be considered when prescribing practical exercise regimens for patients with muscle atrophy.

Differences in fatigability of vastus medialis muscle between patients with limb symmetry index of <90% and ≥90% after chronic anterior cruciate ligament reconstruction

BACKGROUND

A limb symmetry index (LSI) of ≥90% for the quadriceps is recommended for return to sports activity after anterior cruciate ligament reconstruction (ACLR). However, there is no information on differences in muscle fatigability between patients with LSI of <90% and ≥90%. The aim of this study was to assess the difference in quadriceps muscle fatigability on the involved side between post-ACLR patients with LSI of <90% and ≥90%. We hypothesized that there were differences between the two groups in muscle fatigability on the involved side reflecting difference in muscle fiber composition in the vastus medialis (VM) muscle.

METHODS

The study subjects were 18 adult men who had undergone ACLR followed by rehabilitation therapy. LSI was <90% in 10 and ≥90% in 8 adult men. Surface electromyography (EMG) of the VM muscle was recorded during sustained quadriceps muscle isometric contraction. The median frequency (MF) was computed from the raw EMG signal using fast Fourier transform spectrum analysis. The MF slope was also calculated.

RESULTS

There were no differences in anthropometric characteristics, time since ACLR, anterior tibial translation and peak torque of knee extension on the involved side between the two groups. However, MF slope was significantly lower in the LSI ≥ 90% group than the <90% group.

CONCLUSION

Our results demonstrated fatigue-resistant vastus medialis in post-ACLR patients with LSI ≥90% compared to those with LSI <90%. The finding adds support to the use of ≥90% as the cutoff value for LSI for return of post-ACLR patients to sports activity.

Reliability of knee extensor neuromuscular structure and function and functional tests' performance

INTRODUCTION

The aim of this study was to evaluate the intra and inter-rater and inter-analyzer reliability of neuromuscular variables and functional tests.

METHODS

Cross-sectional crossover design. Two independent raters and analyzers evaluated twenty-two healthy subjects. Knee-extensor strength was assessed from three maximal voluntary isometric contractions. Muscle activation was obtained from the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) muscles. VL and RF muscles' architecture [fascicle length (FL), pennation angle (PA), muscle thickness (MT)] was obtained at rest by ultrasound. The time from five sit-to-stand (STS) trials, and the distance from the 6-min walk test (6MWT) were obtained. Intraclass correlation coefficient was determined and classified as strong (r = 0.75-1.00), moderate (r = 0.40-0.74), and weak (r < 0.40).

RESULTS

Strong intra-rater reliability values were observed for strength (r = 0.97), muscle activation [VL (r = 0.91); RF (r = 0.92); VM (r = 0.80)], VL [FL (r = 0.90); PA (r = 0.94); MT (r = 0.99)] and RF [MT (r = 0.85)] muscle architecture, STS (r = 0.95), and 6MWT (r = 0.98). Inter-rater reliability also presented strong values for strength (r = 0.97), muscle activation [VL (r = 0.94); RF (r = 0.79); VM (r = 0.78)], muscle architecture VL [PA (r = 0.81) and MT (r = 0.88)] and RF [MT (r = 0.80)], STS (r = 0.93), and 6MWT (r = 0.98). A moderate correlation VL muscle architecture [FL (r = 0.69)]. Inter-analyzer muscle architecture reliability presented strong VL [FL (r = 0.77); PA (r = 0.76); MT (r = 0.91)] and RF [MT (r = 0.99)].

CONCLUSION

The high intra and inter-rater and inter-analyzer reliability values for most variables is evidence that they can be used for clinical evaluation. Muscle architecture might need a longer training period by different raters and analyzers to increase reliability.

Adductor Canal Versus Femoral Nerve Block after Anterior Cruciate Ligament Reconstruction: A Systematic Review of Level I Randomized Controlled Trials Comparing Early Postoperative Pain, Opioid Requirements, and Quadriceps Strength

PURPOSE

To systematically review the literature to compare the adductor canal block (ACB) with the femoral nerve block (FNB) following primary anterior cruciate ligament reconstruction (ACLR) in terms of early postoperative analgesic requirements and postoperative quadriceps strength.

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase up to August 2019 to identify randomized controlled trials that compared postoperative pain and functional outcomes in patients following primary ACLR with ACB versus FNB. The search phrase used was: adductor canal femoral nerve anterior cruciate ligament. Patients were evaluated based on analgesic consumption and quadriceps muscle strength. Study quality and risk of bias were evaluated with the Modified Coleman Methodology Score and Cochrane risk-of-bias tool respectively.

RESULTS

Five studies (all Level I evidence) were identified that met inclusion criteria, including 221 patients undergoing primary ACLR with ACB (mean age 26.8 years, 68.3% male) and 221 with FNB (mean age 28.2 years, 67.0% male). Statistical assessment for heterogeneity found for opioid consumption of ACB versus FNB groups was I² = 97% (P < .0001). There were no significant differences in analgesic consumption within the first 24 hours following surgery between groups except in 1 study, in which patients receiving ACB required significantly greater analgesics (P < .001). Three studies using 3 different techniques to measure strength found patients receiving ACB to have significantly greater quadriceps muscle function within 24 hours of surgery when compared with patients receiving FNB (P < .05).

CONCLUSIONS

In patients undergoing ACLR, the ACB may provide similar analgesic requirements, and the included studies suggest a potential advantage in preserving muscle strength at short-term (24-48 hours) follow-up when compared with FNB. However, the differences in muscle strength assessments between studies do not allow for strong conclusions.

LEVEL OF EVIDENCE

I, systematic review and meta-analysis of Level I studies.

Reliability and fatigue characteristics of a standing hip isometric endurance protocol

Muscle fatigue is a common consideration when evaluating and rehabilitating athletic injuries. The presence of muscular fatigue has been previously determined by quantifying median frequency (MF) through a power spectral analysis on EMG signals collected throughout an endurance task. Research has not yet determined if a prolonged isometric test in a standing position generates muscular fatigue of the hip. The purpose of this study was to determine the reliability and fatigue characteristics of a standing hip isometric endurance test. Twenty healthy participants completed one 60-s Maximum Voluntary Isometric Contraction of standing hip flexion, extension, adduction, and abduction. MF of the participants' dominant limb rectus femoris (RF), biceps femoris (BF), gluteus maximus (GMax), gluteus medius (GMed) and adductor longus (ADD) was determined via surface electromyography during two sessions, 30-min apart. Reliability values (ICC2,1) were moderate-to-excellent for all time intervals of each action (FlexionRF: >0.80; ExtensionBF: >0.89; ExtensionGMax: >0.60; AdductionADD: >0.78; AbductionGMed: >0.60) and MF significantly decreased over time for all actions. Results suggest the endurance test is a reliable technique to generate muscular fatigue for hip flexion, extension, adduction and abduction. It can be used as a time efficient fatigue protocol specific to the RF, BF, GMax, ADD and GMed.

Exploratory study of electromyographic behavior of the vastus medialis and vastus lateralis at neuromuscular fatigue onset

This study aimed to determine and analyze the neuromuscular fatigue onset by median frequency (MDF) and the root mean square (RMS) behavior of an electromyographic signal (EMG). Eighteen healthy men with no prior knee problems initially performed three maximum voluntary isometric contractions (MVIC). After two days of MVIC test, participants performed a fatiguing protocol in which they performed submaximal knee-extension contractions at 20% and 70% MVIC held to exhaustion. The MDF and RMS values from the EMG signals were recorded from the vastus medialis (VM) and the vastus lateralis (VL). Analysis of the MDF and RMS behavior enabled identification of neuromuscular fatigue onset for VM and VL muscles in 20% and 70% loads. Alterations between the VM and VL in the neuromuscular fatigue onset, at 20% and 70% MVIC, were not significant. These findings suggest that the methodology proposal was capable of indicating minute differences sensible to alterations in the EMG signals, allowing identification of the moment when the MDF and the RMS showed significant changes in behavior. The methodology used was also a viable one for describing and identifying the neuromuscular fatigue onset by means of the analysis of EMG signals.

Eletromiografia do bíceps braquial em contrações dinâmicas

INTRODUÇÃO: A reprodutibilidade da atividade eletromiográfica de superfície (EMG) é mais estudada em protocolos que envolvem contrações isométricas. Alguns fatores relacionados às contrações dinâmicas podem contribuir para a instabilidade do sinal mioelétrico e dificultar a reprodutibilidade da medida da EMG. OBJETIVO: Determinar a reprodutibilidade teste-reteste e quantificar o erro técnico da medida da frequência mediana (FM) e da amplitude (root mean square, RMS) da EMG, em contrações dinâmicas e estáticas. MÉTODOS: Dez sujeitos foram testados em dois dias, sendo a atividade EMG registrada na maior porção do bíceps braquial. No primeiro dia foi feito o teste de uma repetição máxima (1RM) e de contração voluntária máxima (CVM). No segundo dia foram realizadas duas séries de 10 contrações dos flexores do cotovelo com 75% de 1RM, entremeadas por 1 h em repouso. Antes de cada série foi realizada uma CVM. RESULTADOS: Para a FM e RMS foi observado alto coeficiente de correlação intraclasse para o sinal do bíceps braquial (CCI = 0,90-0,98 para a FM; CCI = 0,89-0,94 para o RMS) e de baixo para moderado coeficiente de variação (CV = 2,5-6,2% para a FM; CV = 14,6-16,3% para o RMS) em ambos os testes. Não foi observada diferença significativa entre teste e reteste (p > 0,05). CONCLUSÃO: A FM e o RMS apresentam alta confiabilidade e baixo a moderado erro em contrações estáticas e dinâmicas, possibilitando o uso da EMG para investigação da fadiga e de desordens neuromusculares.

Quadriceps femoris muscle fatigue in patients with knee osteoarthritis

The purpose of this study was to characterize quadriceps femoris muscle fatigue of both lower extremities in patients with knee osteoarthritis (OA). Sixty-two subjects (mean age 68.2 years, standard deviation [SD] ± 7.9 years) with knee OA participated in the study. Significantly higher knee pain was reported in the involved knee than in the contralateral knee, as determined by a visual analog scale. Significant differences were demonstrated between the lower extremities in terms of maximal voluntary isometric contraction, in favor of the less involved leg (P = 0.0001). In contrast, the degree of fatigue of the quadriceps femoris muscle, as measured by the decrement in force production following ten repeated contractions, was significantly higher in the contralateral leg (P = 0.0002). Furthermore, normalization of the fatigue results to the first contraction yielded a similar result (P < 0.0001). Similar results were noted when analysis was performed separately for subjects whose involvement was unilateral or bilateral. The results indicate that, irrespective of the initial strength of contraction, the rate of muscle fatigue in the contralateral leg is significantly higher than in the involved leg. Hypotheses for these unexpected results are suggested. Rehabilitation of patients with knee OA should focus on increasing quadriceps muscle strength and endurance for both lower extremities.

Análise da reprodutibilidade de parâmetros no domínio da frequência do sinal EMG utilizados na caracterização da fadiga muscular localizada

O objetivo deste estudo foi analisar a reprodutibilidade de parâmetros no domínio da frequência do sinal eletromiográfico (EMG) utilizados na caracterização da fadiga muscular localizada. Quinze sujeitos do sexo masculino foram submetidos a um teste de fadiga baseado na extensão isométrica de joelho, sendo realizados em três momentos distintos com intervalos de sete dias. Para avaliar a reprodutibilidade dos dados entres os testes calculou-se o coeficiente de correlação intraclasse (CCI) para a frequência mediana (Fmed) no tempo total de exercício (FmedT), para a Fmed obtida a cada 10% do tempo de exercício (Fmed10%) e para as potências das bandas de frequência, obtidas da divisão do espectro de potência a cada 20 Hz. Os resultados demonstraram: (1) boa reprodutibilidade para a FmedT; (2) boa reprodutibilidade para a Fmed10%; e (3) maior variação no sinal EMG nas bandas de 20 a 120 Hz, no qual se destacam as bandas de 20-40 Hz e de 40-60 Hz, demonstrando maior sensibilidade ao processo de fadiga muscular. Conclui-se que a Fmed é uma variável que apresenta boa reprodutibilidade e que a análise fragmentada do espectro de potência, por meio das bandas de frequência, demonstrou-se sensível as variações que ocorrem no sinal EMG durante a instalação do processo de fadiga, tendo potencial para se tornar um novo método para a caracterização da fadiga muscular localizada.