Neck flexor muscle fatigue is side specific in patients with unilateral neck pain.

Despite the evidence of greater fatigability of the cervical flexor muscles in neck pain patients, the effect of unilaterality of neck pain on muscle fatigue has not been investigated. This study compared myoelectric manifestations of sternocleidomastoid (SCM) and anterior scalene (AS) muscle fatigue between the painful and non-painful sides in patients with chronic unilateral neck pain. Myoelectric signals were recorded from the sternal head of SCM and the AS muscles bilaterally during sub-maximal isometric cervical flexion contractions at 25% and 50% of the maximum voluntary contraction (MVC). The time course of the mean power frequency, average rectified value and conduction velocity of the electromyographic signals were calculated to quantify myoelectric manifestations of muscle fatigue. Results revealed greater estimates of the initial value and slope of the mean frequency for both the SCM and AS muscles on the side of the patient's neck pain at 25% and 50% of MVC. These results indicate greater myoelectric manifestations of muscle fatigue of the superficial cervical flexor muscles ipsilateral to the side of pain. This suggests a specificity of the effect of pain on muscle function and hence the need for specificity of therapeutic exercise in the management of neck pain patients.     

Neck muscles cross-sectional area in adolescents with and without headache – MRI study

Background: Cervical musculature may play an important role in the genesis of tension‐type headache. However, there are no reports on a possible association between the morphometrical features of the neck flexion and extension muscles and adolescence headache. Aim: To examine differences in neck flexion and extension muscles cross‐sectional area (CSA) in adolescents with and without headache. Methods: A population‐based sample of 17‐year‐old adolescents with migraine (N=19), tension‐type headache (N=24) and healthy controls without headache (N=22) was examined. CSA of the neck muscles was measured from axial T1‐weighted magnetic resonance images (MRI). Results: Boys with tension‐type headache showed significantly smaller CSA of right sternocleidomastoid muscle than boys with migraine and girls with tension‐type headache showed significantly smaller CSA of combined right sternocleidomastoid and scalenus muscles than girls with migraine. In addition, boys with migraine had significantly larger CSA of both right sternocleidomastoid and combined right sternocleidomastoid and scalenus muscles, and left semispinalis capitis muscle and combined left semispinalis and splenius muscles than boys without headache. In boys and girls no other significant differences were observed in the CSA of neck flexion or extension muscles. Conclusions: This preliminary work demonstrates that both girls and boys with tension‐type headache and migraine have differences in the size of neck flexion muscles, especially unilaterally. In boys, unilaterally increased size of neck flexion and extension muscles is associated with migraine. These findings, if confirmed in further studies, may have important diagnostic and therapeutic implications for rehabilitation of adolescents with headache.     

Association between blood pressure measures and recurrent headache in adolescents: cross-sectional data from the HUNT-Youth study

The relationship between blood pressure and headache in youth has not been explored and the objective of the present study was to provide data on this association in an adolescent population. Cross-sectional data from a large population-based survey, the Young-HUNT study, on 5,847 adolescents were used to evaluate the association between blood pressure (systolic, diastolic, mean arterial and pulse pressure) and recurrent headache, including migraine and tension-type headache. Increasing pulse pressure was inversely related to recurrent headache prevalence, and both tension-type headache and migraine. For systolic blood pressure such an inverse relationship was present for recurrent headache and tension-type headache prevalence. For migraine, the results were not significant, although there was a tendency in the same direction (p = 0.05). High-pulse pressure has previously been found to be inversely related to the prevalence of migraine and tension-type headache in an adult population. This inverse relationship has now been demonstrated to be present among adolescents also, supporting the results from a previous study in adults, that blood pressure regulation may be linked to the pathophysiology of headache.     

Assessment of skeletal muscle fatigue in men with coronary artery disease using surface electromyography during isometric contraction of quadriceps muscles

OBJECTIVE: To evaluate whether using surface electromyography to assess skeletal muscle fatigue during an isometric exercise has the potential to be clinically useful in patients with coronary artery disease (CAD). DESIGN: Double sample comparative study. SETTING: Cardiac rehabilitation service in France. PARTICIPANTS: Sixteen men with documented CAD and 9 age-matched healthy men. INTERVENTIONS: Assessment of quadriceps skeletal muscle fatigue on an isokinetic apparatus with surface electromyography measurements and a symptom-limited exercise test in a laboratory. MAIN OUTCOME MEASURES: The maximal voluntary isometric force (MVIF) of the quadriceps was quantified as a measure of muscle strength and isometric endurance was defined as the time required to sustain a contraction at 50% of MVIF until exhaustion. Surface electromyography signals were recorded from the vastus lateralis, rectus femoris, and vastus medialis during isometric endurance. The root mean square (RMS) and the median frequency (MF) were directly calculated on a computer and then normalized (as a percentage of the initial value). RESULTS: Muscle strength did not differ significantly between the patients with CAD and the healthy subjects (229+/-21N/m vs 228+/-52N/m), but isometric endurance was reduced (64+/-17s vs 90+/-7s, P <.01). The RMS values showed a significantly higher increase in the healthy subjects versus the patients with CAD for the vastus lateralis and vastus medialis ( P <.001). The MF values were significantly lower for the vastus lateralis, rectus femoris ( P <.01), and vastus medialis ( P <.05) in patients with CAD compared with the healthy subjects. CONCLUSIONS: Skeletal muscle fatigue occurs sooner in men with CAD relative to matched healthy men, despite similar muscle strength. This finding may be the result of an abnormality of skeletal muscle function and may play an important role in measuring functional capacity. In addition, it may be a useful tool to assess the efficacy of cardiac rehabilitation interventions.     

Functional improvement in children and adolescents with primary headache after an interdisciplinary multimodal therapy program: the DreKiP study

BackgroundMore than 2/3 of children and adolescents in Germany regularly suffer from headaches. Headache-related limitations in everyday life, school drop-out and educational impairment are common. Structured therapy programs for young headache patients are widely missing.MethodsOne hundred eleven patients with frequent migraine and/or tension type headache were treated in a 15 hour group program in afternoons, parallel with school, parents received 7 hours of therapy. At the beginning of the program (T0), 6 (T1) and 12 months (T2) after completion, data on headache related disability (PedMidas), headache frequency, intensity, and pediatric pain disability score (PPDI) were prospectively collected to investigate the effects of the therapy.ResultsSeventy-five patients (9-19 years, median = 14; 66.7% female) and their parents provided patient reported outcome measures showing at T1 (65 patients) and T2 (47 patients) reduced headache frequency (last 3 months headache days median T0: 30 days; T1: 18 days, reduction of median 12 days since T0; T2: 13 days, reduction of median 17 days since T0). Linear mixed models revealed significant reduction (T0/T1 p = 0,002; T0/T2 p = 0,001). Reduced headache disability has been reported at T1 and T2 (PedMidas median T0 = 30, T1 = 15, T2 = 7; p < 0,001, p < 0,001 respectively). Follow up data of a subgroup of patients 24 months after the treatment point to sustainable effects.ConclusionsThe interdisciplinary multimodal headache therapy program DreKiP reduces headache frequency and headache related disability significantly 6-12 months following its completion.Trial registrationDRKS00027523, retrospectively registered.Supplementary InformationThe online version contains supplementary material available at 10.1186/s10194-022-01481-1.     

肺炎患儿膈肌疲劳的诊断研究

目的探讨电阻抗呼吸图仪对肺炎惠儿膈肌疲劳的诊断价值。方法用2K—V1型智能电阻抗呼吸图仪分别测定126例肺炎患儿和60例正常小儿的膈肌功能,并根据其一维图中胸腹运动曲线的变化及二维图中M值与a角度的变化判断其膈肌疲劳的程度。结果126例患儿中98例有膈肌疲劳,其中68例为I型膈肌疲劳,30例为Ⅱ型膈肌疲劳。Ⅰ型膈肌疲劳患儿M值为（46．1±8．4）％,α角为（136．7±12．0）°;Ⅱ型膈肌疲劳M值为（17．2±3．2）％,α角为（48．2±9．5）°;对照组M值为（4．3±1．0）％,α角为（31．7±5．2）°（P〈O．01）。膈肌疲劳的程度与临床诊断呼吸衰竭呈高度相关,与年龄的大小呈负相关。结论电阻抗呼吸图仪可作为肺炎膈肌疲劳的临床诊断方法,膈肌疲劳与肺炎患儿呼吸衰竭有相关性。     

Exercise-related fatigue affects joint-driven resistance: comparison of flexor and extensor

[Purpose] Muscle fatigue can affect the inherent properties of muscles. It is important to know how muscle stiffness changes with muscle fatigue and the different effects of the initial and terminal stages of exercise. Therefore, we aimed to examine the effects of bicep and tricep contraction tasks that lead to fatigue on joint-driven resistance of the elbow joint. [Participants and Methods] Twenty-five healthy men were included. Joint-driven resistance of the elbow joint was measured before and after the muscle contraction task. The slope of the regression line of the angle torque at the time of passive movement was calculated as an elastic coefficient and the entire movable range, proximal range, and distal range were compared. [Results] Owing to the muscular contraction of the biceps and triceps, the elastic coefficient increased in the elbow joint during both flexion and extension. The rate of change in the elastic coefficient was lower during the tricep contraction task than during the bicep contraction task. For both tasks, the change in the elastic coefficient varied depending on the range of exercise. [Conclusion] Resistance exercise increased the driven resistance of the joint during passive movement, and this effect was greater during terminal exercises.     

Cervical headache: an investigation of natural head posture and upper cervical flexor muscle performance

In this study, 60 female subjects, aged between 25 and 40 years, were divided into two equal groups on the basis of absence or presence of headache. A passive accessory intervertebral mobility (PAIVM) examination was performed to confirm an upper cervical articular cause of the subjects' headache and a questionnaire was used to establish a profile of the headache population. Measurements of cranio-cervical posture and isometric strength and endurance of the upper cervical flexor muscles were compared between the two groups of subjects. The headache group was found to be significantly different from the non-headache group in respect to forward head posture (FHP) ( t = -5.98, p < 0.00005), less isometric strength ( t = 3.43, p < 0.001) and less endurance ( t = 8.71, p < 0.0005) of the upper cervical flexors. A statistically significant relationship was also established between natural head posture and isometric endurance of the upper cervical flexor musculature which demonstrated that FHP corresponded with a low endurance capacity (c²= 13.2; p < 0.01). The outcome of this study highlights the need to screen for cervical etiology in patients who are suspected of suffering from common migraine.     

Neurophysiological relationship of neuromuscular fatigue and stress disorder in PTSD patients

IntroductionApart from mental disorders, other complications that have been reported in some patients with Post-Traumatic Stress Disorder (PTSD), include physical pain and being quick to fatigue, which can severely affect the patients’ daily life. Therefore, this study aims to evaluate the relationship between PTSD and physical fatigue in people with PTSD.Method18 military men with (n = 9) and without PTSD (n = 9), with an age range of 45–60 years, volunteered to participate. They were randomly assigned into two groups: PTSD and non-PTSD groups. Recording of the surface electromyography (EMG) in a specific muscle was conducted twice in both groups, once at baseline and then again after a single session of fatiguing exercise. Data were analyzed by ANOVA with repeated measure (2✕2) at the significance level of 0.05.ResultsResults showed that there was a significant main effect of intervention on electrical activity and neural conduction variables in the PTSD group (p = 0.04, p = 0.02). There was also an effect of time for the both variables (P < 0.001).ConclusionStress disorders may affect the time to fatigue in PTSD patients and subsequently cause some difficulties in their daily life.     

Course of adolescent headache: 4-year annual face-to-face follow-up study

The objective of this study is to investigate the course of the diagnosis and characteristics of headache in 12- to 17-year-old adolescents during a follow-up period of 4 years. Headache prevalence and characteristics, and even the type of headache show important changes during adolescence. The course of adolescent headache might reveal important insight into the pathophysiology of headache. Subjects who received a single headache diagnosis were invited to participate in a follow-up study consisting of annual face-to-face evaluation of the subjects for 4 years. Subjects who had only one type of headache and who agreed to participate were included in the study. Each subject had four annual semi-structured interviews with a neurology resident. The International Classification of Headache Disorders second edition was used for case definitions. A total of 87 subjects completed the study: 64 girls (73.56%) and 23 boys (26.44%) (p = 0.016). The headache type included migraine in 50 adolescents (57.47%), tension type headache in 24 (27.59%), secondary headache in 5 (5.7%), and non-classifiable headache in 8 (9.2%). Headache has not remitted in any of the subjects. Headache diagnosis has changed in eighteen (20.69%) subjects at least once during the follow-up period. There was transformation of headache type in 4 of 50 with migraine (8%), 10 of 24 with tension-type headache (TTH) (41.7%), and 4 of 13 with other headaches (30.8%). In conclusion, transition of headache types from one type to another (more than once in some adolescents) and variability of diagnosis throughout the years strongly support the continuum theory of headaches.     

Influence of smartphone use on the median frequency of mastigatory and trapezius muscles in women - a Pilot study

IntroductionThe use of smartphones is growing every year, and their excessive use can cause adverse physical and mental effects.AimThis study aimed to evaluate the influence of smartphone use on the median frequency of the masticatory muscles and upper trapezius muscles in healthy women.MethodSix healthy young women were evaluated. All the volunteers underwent a submaximal bite test to evaluate their masticatory muscles. In addition, the volunteers underwent a test for bilateral shoulder elevation to a submaximal load to evaluate their upper trapezius muscles. Both protocols were performed before and after a task using the smartphone for 30 min. Median frequency (MF) values were collected during the submaximal bite and submaximal shoulder elevation tests.ResultsData were analyzed using specific statistical tests. A statistically significant reduction in the MF for all the masticatory muscles was observed in the bilateral bite task when comparing pre and post smartphone use (p < 0.005). A significant reduction in the MF was also found for the right upper trapezius when comparing pre and post smartphone use in the shoulder elevation task (p = 0.001).ConclusionIt appears that prolonged smartphone use may contribute to fatigue in the masticatory and upper trapezius muscles. Therefore, guidelines for smartphone users should include advice on the moderate use of this device.     

Increases in local pressure pain thresholds after muscle exertion in women with chronic shoulder pain

OBJECTIVE: To examine the relation between muscular tenderness and local muscular fatigue. DESIGN: Before-after trial, measuring pressure pain thresholds and signs of local muscular fatigue by using surface electromyography before, after, 10 minutes after, and 20 minutes after intervention. SETTING: University rehabilitation department in Sweden. PARTICIPANTS: Nineteen female hospital cleaners with unilateral chronic shoulder pain for 1 year. No previous trauma, surgery, or signs of systemic or neurologic disease. INTERVENTION: Static abduction endurance test with submaximal unilateral activation of the trapezius and deltoid muscles. MAIN OUTCOME MEASURES: Pressure pain thresholds and electromyographic fatigue parameters (root mean square [RMS]; mean power frequency [MPF]). RESULTS: Mean normalized pressure pain threshold values increased significantly (95% confidence interval [CI]) and lasted for 20 minutes: in the trapezius, threshold values increased to 115% to 120% (95% CI, 100%-140%; P=.04-.05); and in the deltoid, the threshold increased to 112% to 115% (95% CI, 100%-130%; P=.02-.05). Development of significant electromyographically defined fatigue was seen: in the trapezius, the RMS increased to 130% (95% CI, 119%-141%), and in the deltoid, the MPF decreased to 78% (95% CI, 74%-82%), but normalized within 15 seconds to 10 minutes. CONCLUSION: Lasting bilateral increases in pressure pain thresholds but transient local muscular fatigue were seen after a unilateral static endurance test. The sensitivity of the sensory nervous system may change during a static muscle contraction and sometimes contributes to a localized sensation of numbness.     

Motor innervation of the flexor pollicis brevis: an electromyographic study.

Percutaneous stimulation of the ulnar and median nerves at the wrist, with simultaneous recording of action potentials on a standard electromyograph oscilloscope, was performed to observe the motor innervation of the flexor pollicis brevis muscle. Both the deep and the superficial heads of the muscle were studied in twenty-three subjects. Results showed that the most common pattern of innervation was exclusive ulnar nerve supply in both heads, with 52.4 percent of the subjects showing this pattern. Dual supply by both median and ulnar nerves occurred next in frequency with 19.0 percent showing this pattern in both heads of the muscle. Exclusive median nerve supply was observed in only 9.5 percent of the total cases studied. The remaining 19 percent showed varying patterns, with each head of the muscle supplied differently. If no differentiation between deep and superficial heads is made, this 19 percent may be considered as dual innervation of the muscle. In this case, it may be concluded that 38 percent of the muscles studied showed some type of dual innervation.     

Surface EMG based muscle fatigue evaluation in biomechanics

In the last three decades it has become quite common to evaluate local muscle fatigue by means of surface electromyographic (sEMG) signal processing. A large number of studies have been performed yielding signal-based quantitative criteria of fatigue in primarily static but also in dynamic tasks. The non-invasive nature of this approach has been particularly appealing in areas like ergonomics and occupational biomechanics, to name just the most prominent ones. However, a correct appreciation of the findings concerned can only be obtained by judging both the scientific value and practical utility of methods while appreciating the corresponding advantages and limitations. The aim of this paper is to serve as a state of the art summary of this issue. The paper gives an overview of classical and modern signal processing methods and techniques from the standpoint of applicability to sEMG signals in fatigue-inducing situations relevant to the broad field of biomechanics. Time domain, frequency domain, time–frequency and time-scale representations, and other methods such as fractal analysis and recurrence quantification analysis are described succinctly and are illustrated with their biomechanical applications, research or clinical alike. Examples from the authors’ own work are incorporated where appropriate. The future of this methodology is projected by estimating those methods that have the greatest chance to be routinely used as reliable muscle fatigue measures.     

Validity and everyday clinical applicability of lumbar muscle fatigue assessment methods in patients with chronic non-specific low back pain: a systematic review

Purpose: This systematic literature review aimed at examining the validity and applicability in everyday clinical rehabilitation practise of methods for the assessment of back muscle fatiguability in patients with chronic non-specific low back pain (CNSLBP).

Methods: Extensive research was performed in MEDLINE, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Embase, Physiotherapy Evidence Database (PEDro) and Cochrane Central Register of Controlled Trials (CENTRAL) databases from their inception to September 2014. Potentially relevant articles were also manually looked for in the reference lists of the identified publications. Studies examining lumbar muscle fatigue in people with CNSLBP were selected. Two reviewers independently selected the articles, carried out the study quality assessment and extracted the results. A modified Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) scale was used to evaluate the scientific rigour of the selected works.

Results: Twenty-four studies fulfilled the selection criteria and were included in the systematic review. We found conflicting data regarding the validity of methods used to examine back muscle fatigue. The Biering-Sorensen test, performed in conjunction with surface electromyography spectral analysis, turned out to be the most widely used and comparatively, the most optimal modality currently available to assess objective back muscle fatigue in daily clinical practise, even though critical limitations are discussed.

Conclusions: Future research should address the identification of an advanced method for lower back fatigue assessment in patients with CNSLBP which, eventually, might provide physical therapists with an objective and reliable test usable in everyday clinical practise.

• Implications for Rehabilitation

• Despite its limitations, the Biering-Sorensen test is currently the most used, convenient and easily available fatiguing test for lumbar muscles.

• To increase validity and reliability of the Biering-Sorensen test, concomitant activation of synergistic muscles should be taken into account.

• Pooled mean frequency and half-width of the spectrum are currently the most valid electromyographic parameters to assess fatigue in chronic non-specific low back pain.

• Body mass index, grading of pain and level of disability of the study population should be reported to enhance research quality.

     

New trends in treatment of muscle fatigue throughout rehabilitation of elderlies with motor neuron diseases

Muscle fatigue is a problem in rehabilitation, particularly in elderlies and patients with motor neuron diseases. There are high contradictions in the effectiveness of the used methods to decrease muscle fatigue during rehabilitation. They mainly concentrate on increasing rest periods, decreasing training load, or using an ascending intensity of manner of exercise. The training should focus on the newly discovered sensory system of muscle fatigue because of the important role of the sensory system in driving the motor system. Thus, this editorial provides insight on using proprioceptive training to enhance the sensory system of muscle fatigue.     

The prevalence of headache with emphasis on tension-type headache in rural Tanzania: a community-based study

The aim of the study was to assess the prevalence of headache with special attention to tension-type headache (TTH) in a rural area in northern Tanzania. A door-to-door study was performed using a standardized and validated questionnaire. A total of 7412 participants were screened. The total headache prevalence during the past year was 12.1%; the overall 1-year prevalence of TTH was 7%; 5% reported episodic TTH and 0.4% chronic TTH. Borderline cases (International Headache Society code 2.3) were described in 1.6%. The prevalence of headache was highest in the 41–50-year-old group in women and in the 61+ age group in men. This is the first account of the prevalence of TTH in a rural Tanzanian population, and shows that headache in general and, more specifically, TTH are prevalent disorders that deserve attention. However, the prevalence of primary headache seems to be lower than in Western countries.     

Multifidus muscle size in adolescents with and without back pain using ultrasonography

Objective

The purposes of this study were; a) to compare multifidus muscle cross sectional area (CSA) in male adolescents suffering from low back pain (LBP) with healthy male adolescents using ultrasonography (US), and b) to assess the correlation between multifidus muscle size and demographic variables.