Muscular Factors Research Articles

Effects of joint angle and age on ankle dorsi- and plantar-flexor strength

This study aimed at examining the effects of joint angle and age on the maximal voluntary contraction (MVC) torque, for the agonist and antagonist muscle groups around the ankle, i.e., the dorsi- and plantar-flexors. To this aim, neural and muscular factors were investigated in two groups of healthy men: 11 young (mean age, 24 years) and 18 older (mean age, 78 years). Plantar-flexion (PF) and dorsiflexion (DF) isometric MVC torques were measured in three different ankle joint angles and surface electromyographic activities of the triceps surae and of the tibialis anterior muscles were recorded. The main findings were that the DF-to-PF MVC torque ratio varied with joint angle and age, indicating that aging affected at different rates the two muscle groups: this ratio was always higher in older adults because of the PF strength decline with aging. Furthermore, the DF MVC torque–angle relationship appeared to be especially explained by neural factors, whereas the relationship in PF seemed to be mainly due to muscular parameters. These relationships would not be a discriminating factor between the two age groups. As a consequence, measurements at one ankle joint angle, whatever the angle, are thus enough to examine the differences within age groups and to perform a rapid assessment of the imbalance at the ankle joint.

Relative Contribution of Neural Versus Muscular Factors in Disuse-Induced Strength Loss

Relative Contribution of Neural Versus Muscular Factors in Disuse-Induced Strength Loss

Adaptations in human neuromuscular function following prolonged unweighting: II. Neurological properties and motor imagery efficacy

Strength loss following disuse may result from alterations in muscle and/or neurological properties. In this paper, we report our findings on human plantar flexor neurological properties following 4 wk of limb suspension [unilateral lower limb suspension (ULLS)], along with the effect of motor imagery (MI) training on these properties. In the companion paper (Part I), we report our findings on the changes in skeletal muscle properties. Additionally, in the present paper, we analyze our findings to determine the relative contribution of neural and muscular factors in strength loss. Measurements of central activation, the H-reflex, and nerve conduction were made before and after 4 wk of ULLS (n = 18; 19-28 yr). A subset of the subjects (n = 6) performed PF MI training 4 days/wk. Following ULLS, we observed a significant increase in the soleus H-reflex (45.4 +/- 4.0 to 51.9 +/- 3.7% expressed relative to the maximal muscle action potential). Additionally, there were longer intervals between the delivery of an electrical stimulus to the tibial nerve and the corresponding muscle action potential (M-wave latency; mean prolongation 0.49 ms) and H-reflex wave (H-wave latency; mean prolongation 0.46 ms). The efficacy of MI on strength was ambiguous, with no significant effect detected (although a modest effect size was observed; eta2 = 0.18). These findings suggest that unweighting induces plastic changes in neural function that appear to be spatially distributed throughout the nervous system. In terms of the relative contribution of neural and muscular factors regulating strength loss, we observed that neural factors (primarily deficits in central activation) explained 48% of the variability in strength loss, whereas muscular factors (primarily sarcolemma function) explained 39% of the variability.

Pressure pain thresholds in adolescent patients with chronic tension-type headache

AbstractThe pathophysiological mechanisms underlying chronic tension-type headache are still unclear. The aim of the present study was to investigate tenderness of pericranial muscles by examining pressure pain thresholds in adolescents suffering from chronic tension-type headache. A group of 35 patients with chronic tension-type headache was compared to 70 healthy controls in terms of pressure pain thresholds. A conventional hand-held algometer was used to measure the pressure pain thresholds in the upper trapezius, suboccipitalis, and frontalis muscles. Pressure pain thresholds were significantly lower in patients than in healthy controls. Pressure pain threshold values of bilateral trapezius muscles were significantly negatively correlated with the pain intensity. There was no correlation between the pressure pain threshold values and duration, or frequency of headache. Along with results obtained previously, the present data support the hypothesis that muscular factors may be an important factor for t...

Longitudinal Changes of Maximal Short-Term Peak Power in Girls and Boys during Growth

The aims of this study are twofold: first, to analyze the influence of age, body mass, and lean leg volume (LLV) on short-term leg peak power (Pmax) of young females and males during growth using multilevel regression analysis and, second, to compare the regression results of boys and girls. The individuals were 100 girls and 109 boys aged 7.5-17.5 yr old. Pmax, LLV, and mass were determined on two occasions using the cycling force-velocity test. The optimal force (Fopt) and pedaling frequency (Vopt) corresponded to the force and pedaling frequency at Pmax. It was observed that the increase of Pmax doesn't depend on gender until the age of 14. From that age, Pmax values are significantly lower in girls than in boys. In girls, LLV is the main predictor of Pmax variance (68%; P < 0.001), whereas in boys it is age (57%; P < 0.001). Results of ANCOVA were that for the same leg length (LL), Vopt is significantly (P < 0.001) higher in boys than in girls. It also indicated that for the same LLV, there are no significant (P > 0.05) gender differences of Fopt. These results illustrated that during the growth period, the increase of Pmax is significantly higher in boys than in girls. Qualitative muscular factors (Type II fiber, glycolytic ability, motor coordination, and motor unit activation) may account for the significantly higher Pmax production in boys than in girls. Precisely, the gender differences might be explained by neuromuscular determinants of contraction velocity. In conclusion, children should develop their neuromuscular determinants of contraction velocity rather than their lean leg volume.

Painful Myopathies–Metabolism of Muscle Cells and Metabolic Myopathies

SUMMARYMyalgias may be caused by intrinsic muscular factors [inflammation, mechanical disturbances, ischemia, metabolic abnormalities, membrane alterations] or by extrinsic factors like diseases of the peripheral or central nervous system. Primary metabolic myopathies are mostly caused by disturbances of energy metabolism. Usually these patients present with exercise-induced myalgia, which is commonly associated with muscle weakness. If rhabdomyolysis occurs further thorough investigations for a metabolic myopathy are mandatory. The pathogenesis of myalgia is thought to be related to certain biochemical mediators. Disturbances of anaerobic and aerobic muscle metabolism are typical for metabolic myopathies causing myalgia. These disorders are due to enzyme malfunction in the following pathways: glycogenolysis, glycolysis, β-oxidation of fatty acids, and the respiratory chain. Treatment of metabolic myopathies is limited. Non-specific measures include physiotherapy, non-steroidal analgesics, chinine, and L-...

Exercise after heart transplantation.

Exercise intolerance in heart transplant recipients (HTR) has a multifactorial origin, involving complex interactions among cardiac, neurohormonal, vascular, skeletal muscle and pulmonary abnormalities. However, the role of these abnormalities may differ as a function of time after transplantation and of many other variables. The present review is aimed at evaluating the role of cardiac, pulmonary and muscular factors in limiting maximal aerobic performance of HTR, and the benefits of chronic exercise. Whereas pulmonary function does not seem to affect gas exchange until a critical value of diffusing lung capacity is attained, cardiac and skeletal muscle function deterioration may represent relevant factors limiting maximal and submaximal aerobic performance. Cardiac function is mainly limited by chronotropic incompetence and diastolic dysfunction, whereas muscle activity seems to be limited by impaired oxygen supply as a consequence of the reduced capillary network. The latter may be due to either immunosuppressive regimen or deconditioning. Endurance and strength training may greatly improve muscle function and maximal aerobic performance of HTR, and may also reduce side effects of immunosuppressive therapy and control risk factors for cardiac allograft vasculopathy. For the above reasons exercise should be considered an important therapeutic tool in the long-term treatment of heart transplant recipients.

Relationships of Concentrations of Endocrine Factors at Antemortem and Postmortem Periods to Carcass Weight and Backfat Thickness in Pigs

Carcass weight and backfat thickness are two of important elements in determining the carcass trait in pigs and are studied on animal genetics, nutrition, and endocrinology. Growth factors stimulate or inhibit the proliferation and differentiation of various cells. In particular, insulin-like growth factors (IGFs), transforming growth factor (TGF)-β, and epidermal growth factor (EGF) are involved in the growth and maintenance of muscle. Also, dehydroepiandrosterone-sulfate (DHEA-S) and cortisol are known to be related to the obesity and subcutaneous fat depth in pigs. Therefore, this study was performed to relate growth factors (IGFs, TGF-β1, and EGF) and hormones (cortisol and DHEA-S) concentrations at antemortem and postmortem periods to carcass traits including carcass weight and backfat thickness. Blood and m. Longissimus were collected in pigs at antemortem (30 days before slaughter) and postmortem periods. After slaughtered, carcass weight and backfat thickness were measured. Growth factors and hormones in serum and m. Longissimus were measured by radioimmunoassay or enzyme-linked imuunosorbent assay. Before antemortem period, serum IGF-I and -II concentrations were positively correlated with the carcass weight and backfat thickness in gilts, and the concentrations of TGF-β1 and cortisol in barrows show the correlation with only carcass weight. Also, the positive correlations of muscular IGFs and TGF-β1 at postmortem 45 min with the carcass weight and backfat thickness were detected. Consequently, these results suggest that the serum and muscular endocrine factors are involved in the carcass weight and backfat thickness in pigs.

Knee muscle torques of healthy adults with tibia vara: Hypothetical relationship to medial compartment knee osteoarthrosis

Background: In earlier work we noted that women with medial compartment knee osteoarthrosis and varus deformity displayed greater neuromuscular deficiencies of quadriceps muscles than those with normal tibial alignment when tested isokinetically at 90° sec -1 and at 0° sec -1 using an isokinetic dynamometer. Purpose: The present purpose was to provide further insight into the potential influence of muscular factors in the development of medial compartment knee osteoarthrosis. Methods: Because our previous findings indicated significantly greater torque generating problems at higher isokinetic speeds than lower speeds among adults with varus alignment deformities, and prior work is strongly associated with isometric test outcomes, we elected to perform quantitative measures of maximal isometric knee torques generated 0° sec -1 and to compare these to validated goniometric alignment measures of the lower legs of 14 health individuals exhibiting genu varum on a single test occasion. Results. The analyses revealed: 1) a significant inverse relationship between the right quadriceps and hamstrings muscle torque and right tibia varus measures (r = -0.59; r = -0.66), and between the left hamstrings muscle torque and left tibia vara measures (r = -0.62) (p < 0.05) when controlling for gender; 2) antagonist-agonist knee torque ratios that tended to vary inversely with the magnitude of the prevailing varus deformity; 3) the presence of asymmetric tibia vara magnitudes with greater angulations recorded for the subject's right side, regardless of limb dominance; 4) greater varus angulation deformities for both legs of the males compared to the females (p < 0.05). Conclusions: The slope of the regression line linking the maximal knee extensor and flexor torques of healthy young adults tends to vary inversely with the degree of varus angulation as presently recorded. There may be considerable intra-individual and gender differences in the manifestation of this finding. These observations may have a bearing on the etiology and pathogenesis of uni- or bilateral medial compartmental knee joint disease in healthy adults exhibiting genu varum, hence warranting further study using more sophisticated measures and isokinetic testing at different angular velocities.

Mechanisms contributing to knee extensor strength loss after prolonged running exercise.

The aim of this study was to identify the mechanisms that contribute to the decline in knee extensor (KE) muscles strength after a prolonged running exercise. During the 2 days preceding a 30-km running race [duration 188.7 +/- 27.0 (SD) min] and immediately after the race, maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve of 12 trained runners. Superimposed twitches were also delivered during isometric maximal voluntary contraction (MVC) to determine the level of voluntary activation (%VA). The vastus lateralis electromyogram was recorded. KE MVC decreased from pre- to postexercise (from 188.1 +/- 25.2 to 142.7 +/- 29.7 N x m; P < 0.001) as did %VA (from 98.8 +/- 1.8 to 91.3 +/- 10.7%; P < 0.05). The changes from pre- to postexercise in these two variables were highly correlated (R = 0.88; P < 0.001). The modifications in the mechanical response after the 80-Hz stimulation and M-wave peak-to-peak amplitude were also significant (P < 0.001 and P < 0.05, respectively). It can be concluded that 1) central fatigue, neuromuscular propagation, and muscular factors are involved in the 23.5 +/- 14.9% reduction in MVC after a prolonged running bout at racing pace and 2) runners with the greatest KE strength loss experience large activation deficit.

On longitudinal bone growth, short stature, and related matters: insights about cartilage physiology from the Utah paradigm.

Precursor cell division in growing cartilage determines human height, the lengths of the spine and limb bones, the alignment of joints, spines and limbs, and the ratio of spinal length to limb length. That division also helps to determine the sizes and shapes of joints, apophyses and epiphyses. Ideas about what controls those facts are changing. To former views, in which mainly genetic and humoral factors controlled them, the Utah paradigm of skeletal physiology adds long-overlooked biomechanical including muscular factors. These three kinds of factors would collaborate in controlling the precursor cell division that determines the above skeletal features. Problems with that control clearly cause or help to cause many clinical disorders. Examples include short stature, gigantism, premature and delayed skeletal maturation, some changes in fracture patterns associated with puberty, joint malalignments, congenital hip dysplasia, scoliosis, limb torsions, the ball-and-socket ankle, and some skeletal abnormalities in Marfan's syndrome and the osteochondrodystrophies. The physiology such things depend on has matured sufficiently to justify a review for pediatricians, endocrinologists and other clinical specialists, and many basic scientists.

Clinical neurophysiology of chronic daily headache

The pathophysiology of chronic daily headache is unclear. Clinical research aiming to elucidate causative mechanisms is often confounded by the variability of factors involved. Furthermore, there is a recent trend to use neurophysiological tests in the investigation of functional disorders in brain structures. In order to evaluate the pathophysicology of chronic daily headache, several methodologies have been employed. The aim of the present review is to relate the obtained results in the most frequently used neurophysiological tests to possible pathophysiological mechanisms of chronic daily headache. The neurophysiological findings suggest that a common neuronal dysfunction redisposes to primary headaches subtypes, whose chronicization may depend upon many factors, such as the influence of peripheral muscular factors and the dysfunction in central nociceptive modulation. These factors may explain the large variability observed in clinical features.

Ratings of perceived exertion (RPE) as an index of aerobic endurance during local and general exercises

The main purpose of this study was to assess the correlations of RPE with indicators of endurance (critical power), exhaustion time and the electromyographic activity of a relevant muscle during general and local exercises. Eight healthy subjects participated in the study. During the first session, Maximal Aerobic Power (MAP) was measured by means of an incremental cycling exercise on a Monark ergometer. At 1-week intervals the participants performed a general or local exhausting exercise, which consisted of a cycle exercise (60, 73, 86 or 100% MAP) and a knee extension exercise (lifting a load between 17.5 and 32.5 kg every 3 s), respectively. The critical powers corresponding to cycling (CPcycling) and knee extension (CPknee) were calculated from the slope of the linear relationship between exhaustion time (t lim) and work. Rate of perceived exertion, concerning the whole body (overall RPE [RPEov]), RPE concerning the exercising muscles (muscular RPE [RPEmu]) and exhaustion time were measured. During the last session, the integrated electromyogram of the right Vastus Lateralis (iEMG s−1) was measured during short (20 s) cycling and knee extension nonexhausting exercises, with the same electrode location, at the different power outputs used during the exhausting exercises. The relationships between RPEmu at the fifth minute and log t lim and between iEMG% (percentage of the iEMG s−1 corresponding to 100% MAP during cycling) and log t lim were similar for the cycling and knee extension exercises. The mean values of RPEmu at the fifth minute of exercise calculated for CPcycling and CPknee were almost equal (12.3 ± 1.7 versus 12.2 ± 0.9). Similarly, the mean values of iEMG% corresponding to CPcycling and CPknee were equal (78.44 versus 79.02%). These results suggest that RPEmu is related to aerobic endurance and that the possibility of sustaining a high percentage of maximal aerobic power during a general exercise is mainly related to local muscular factors.

Factor analysis and somatotyping, are these two physique classification methods comparable?

SummaryThe aim of this study was to investigate the correspondence of physique structures estimated by the Heath-Carter anthropometric somatotyping method and a factor analysis based on the same set of 10 variables used by Heath-Carter. The investigation was carried out on a group of 200 healthy young adults of 20 years of age who were students of physical education. The mean somatotype was 2.7–4.6–3.0 for the males and 3.3–3.4–3.1 for the females. The 73% of the total variance in males and 75% in females were represented by three factors. They were identified as muscular, fatness and skeletal factors in the males, and in the females as muscular-trunk fatness, skeletal and limb fatness factors. A PCA gives different results depending on the measurements used for the calculation. The same set of variables as for the somatotyping method were used intentionally to extract the PCA factors and to evaluate the possible correspondence between these factors and the Heath-Carter components. On the basis of the correlation between the factors and the somatotype components, one can conclude that there is: (1) a high correspondence between endomorphy and fatness factors in both sexes; (2) that mesomorphy correlated positively with the muscular factor in males and negatively with the skeletal factor in both sexes; and (3) that ectomorphy was highly positively correlated with the skeletal factor and negatively with the other two factors in both sexes. Factors and somatotype components do not correspond exactly which leads to the following conclusions: (1) The three somatotype components cannot be identified as orthogonal factors in a factorial analysis based on the same measurements as for the somatotype, e.g. the ectomorphy component is not an independent factor in males or in females; (2) The muscle measurements and bone width used to estimate mesomorphy in somatotyping scored in two independent factors; and (3) The factor structure of the 10 measurements was sex dependent.

Mechanical and muscular factors influencing the performance in maximal vertical jumping after different prestretch loads

The objective of the present work was to study the interaction between the tendon elasticity, the muscle activation-loading dynamics, specific actions of the biarticular muscles, preloading and jumping performance during maximal vertical jumping. Six male expert jumpers participated in the study. They performed maximal vertical jumps with five different preloads. The kinematics and dynamics of the jumping movements were analysed from force plate and high speed film recordings. The amount of elastic energy stored in the tendons of the leg extensor muscles was calculated by a generalised tendon model, and the muscle coordination was analysed by surface EMG. The best jumping performances were achieved in the jumps with low preloads (counter movement jumps and drop jumps from 0.3 m). A considerable amount of the energy imposed on the legs by prestretch loading was stored in the tendons (26 ± 3%), but the increased performance could not be explained by a contribution of clastic energy to the positive work performed during the push off. During the preloading, the involved muscles were activated at the onset of the loading. Slow prestretches at the onset of muscle activation under relatively low average stretch loads, as observed during counter movement jumps and drop jumps from 0.3 m, prevented excessive stretching of the muscle fibres in relation to the tendon length changes. This consequently conserved the potential of the muscle fibres to produce positive work during the following muscle-tendon shortening in concert with the release of the tendon strain energy. A significant increase in the activity of m. rectus femoris between jumps with and without prestretch indicated a pronounced action of m. rectus femoris in a transport of mechanical energy produced by the proximal monoarticular m. gluteus maximus at the hip to the knee and thereby enhanced the transformation of rotational joint work to translational work on the mass centre of the body. The changes in muscle activity were reflected in the net muscle powers. Vertical jumping is like most movements constrained by the intended direction of the movement. The movements of the body segments during the prestretches induced a forward rotation and during the take off, a backward rotation of the body. A reciprocal shift in the activities of the biarticular m. rectus femoris and m. semitendinosus indicated that these rotations were counteracted by changes in the direction of the resultant ground reaction vector controlled by these muscles. The rotational actions around the mass centre of the body should be minimised in maximal vertical jumping because the muscle work used to control these actions is lost for the achievement of jumping height.

Pulmonary function and symptom-limited exercise stress testing in subjects with late sequelae of poliomyelitis

Sixty-eight subjects, consecutively admitted to our rehabilitation hospital with a presumptive postpolio syndrome, were examined by pulmonary function and symptom-limited exercise stress testing. The purpose of this investigation was to study how many of these subjects could be classified as suffering from cardiorespiratory deconditioning. The subjects had moderately reduced lung function of restrictive type, and none of the subjects had forced expiratory volume for one second (FEV1) below 30% of predicted value, indicating that hypoventilation would probably not occur. A pronounced reduction in maximal oxygen uptake (max VO2) was seen, especially in women. The maximal heart rate (max HR) values were above 70% of predicted values in all but one subject, indicating that the subjects might benefit from endurance training. Fifteen subjects had a suspected pulmonary limitation due to the exercise, with the ratio ventilation/maximal voluntary ventilation (V/MVV) above 70%. However, max HR in these subjects did not differ from that in the subjects with the ratio V/MVV below 70%. Thirteen other subjects had a ratio V/MVV &lt; 70% but did not achieve respiratory quotient (R) &gt; 1.0 and/or capillary lactate concentration &gt; 4 mmol/l during exercise, indicating that muscular factors limited the exercise. These results indicate that cardiorespiratory deconditioning was considerable in most of our subjects with postpolio syndrome.

Development of the factors that have effects upon gaining ball speed in kicking motion

The purpose of this study is to investigate the development of factors that have effects upon gaining ball-speed in kicking motion under two different ball conditions: stationary and tee-up. Fifty one boys aged from 5 to 12 years, were filmed by the use of a high-speed camera operated at 64fps while they were kicking. Multiple regression analysis was applied to get interrelationship among ball speed, maximal swing speed, swing speed, ankle angles and knee angles at the impact. At each stage, from 5 to 12 years of age, the ball speed depended on the maximal swing speed as a whole, especially remarkable under 9 years of age. At the stage of 9 and 10 years of age, ball speed was supposed to depend upon other technical factors as well. At stage of 11 and 12 years of age, in addition to the maximal swing speed, other muscular factors might also be related to the ball speed.

Muscle tenderness and pressure pain thresholds in headache. A population study

Tenderness and pain thresholds in pericranial muscles were studied in a random sample of 735 adults aged 25–64 years. This study was a part of a multifaceted, epidemiological study of different headache disorders. Manual palpation and pressure pain threshold were performed by observers blinded to the persons' history of headache. The aim of the study was to evaluate the possible role of pericranial myofascial nociception in headache pathogenesis. Tenderness in migraineurs did not differ from non-migraineurs. Subjects with episodic tension-type headache and females with chronic tension-type headache were more tender than the rest of the population, and males without any experience of headache were less tender than the rest of the male population. A strong positive correlation between tenderness and frequency of tension-type headache was found (males: P < 10 −4; females: P < 10 −5), while no relation between tenderness and migraine frequency was seen ( P = 0.43). In subjects having actual headache at the day of examination tenderness was 32% increased compared to a matched group with identical usual frequency of headache, but without headache during the examination. A significant relation of tenderness to the recency of last episode of headache was detected in both sexes after control for usual frequency and actual headache (males: P < 10 −3; females: P < 10 −4). Pressure pain thresholds were largely normal indicating normal pain processing and contradicting the idea that tension-type headache mainly is due to generally increased pain sensitivity. This study supports the pathogenetic importance of muscular factors in tension-type headache, while muscular factors are of no primary importance in migraine.

Voluntary strength, evoked twitch contractile properties and motor unit activation of knee extensors in obese and non-obese adolescent males

The purpose of this study was to determine whether neural and/or muscular factors contributed to the inferior strength-related motor performances of obese adolescents. Subjects were 10 non-obese (14.6% fat) and 11 obese (32.3% fat) males matched for age (15-18 years), level of maturity (Tanner stages IV and V), lean body mass, and height. Peak torque (PT) was measured during maximal voluntary isometric (IS) and isokinetic (IK) knee extension (KE). Peak twitch torque (TT), time to peak torque (TPT), and half-relaxation time (HRT) of the knee extensors were elicited by percutaneous electrical stimulation. The interpolated twitch technique was used to determine the extent of motor unit activation (% MUA) during maximal voluntary IS KE. Knee extensor cross-sectional area (CSA) was determined by computed axial tomography taken at the mid-thigh. All strength and area measurements were made on the right side of the body. Obese subjects had significantly (P less than 0.05) lower maximal voluntary IS and IK KE strength normalized for body weight, and significantly lower % MUA during IS KE. There were no significant differences (P greater than 0.05) between groups for absolute or normalized (for the product of muscle CSA and height) ISPT, IKPT, and TT, knee extensor CSA, or TPT and HRT. These results suggest that reduced MUA and a lower strength per mass ratio (due to excess fat) are probably important contributing factors to the poorer motor performances of the obese, especially for complex motor tasks involving large muscle groups and the support or moving of body weight.

Tension headache--a review

Tension headache (TH) is an ill-defined headache syndrome, characterized by bilateral, daily headaches with fronto-occipital localisation. TH is often accompanied by a migraine and an abuse of analgesics and/or ergotamine. In the etiology of TH vascular, muscular and psychogenic factors are assumed. Floating transitions to common migraine are discussed. The increased muscle tension is not specific for TH, but more probably a consequence of TH. In addition a decrease of the pain threshold with a deficiency of the antinociceptive system is supposed. The efficacy of tricyclic antidepressives in TH is based on potentiation of serotonergic and noradrenergic mechanisms and - besides their analgetic potencies - upon an increase of the pain threshold. TH prophylaxis is indicated if patients suffer from TH more than ten times per month. Medication are tricyclic antidepressives of the amitriptyline-type. Prophylaxis of TH can only be successful if a simultaneous abuse of analgesics and/or ergotamine is discontinued. In addition, EMG-biofeedback, as well as relaxation - and vasoconstriction training might be helpful in specific cases.