An anatomical study of the proximal hamstring muscle complex to elucidate muscle strains in this region.

Muscle strain injuries are common in sports, and a high incidence is reported for the hamstring muscles, especially in the proximal region, where the long head of the biceps femoris muscle is most frequently affected. To look for some architectural peculiarities, which would make this muscle vulnerable, 101 legs of embalmed human cadavers were dissected and descriptively examined, morphometric data were obtained in the proximal region, and slices of plastinated specimens were microscopically examined. The 3 muscles composing the proximal hamstring complex are partly twisted around each other and possess common fibrous adhesions. Biceps femoris (BF) and semitendinosus (ST) muscles form a common head, to which the ST contributes the majority of fascicles extending 9 cm down from the ischiac tuberosity, thereby attaching to the common tendon at a remarkable pennation angle. The first BF fascicles origin from the common tendon only at 6 cm distance from the ischiac tuberosity. It is concluded that the high incidence of proximal BF strains may be a misinterpretation due to insufficient imaging and the complex architecture. It is suggested that the pennation angle at which the ST inserts to the common tendon makes this muscle especially vulnerable for strains during forced eccentric contractions.

Skeletal muscle pathways of contraction-enhanced glucose uptake.

Muscle contraction acutely increases glucose transport in both healthy and type 2 diabetic individuals. Since glucose uptake during muscle contraction has been observed in the absence of insulin, the existence of an insulin-independent pathway has been suggested to explain this phenomenon. However, the exact mechanism behind the translocation of GLUT4 vesicles through the sarcolemma during muscle contraction is still unknown. Some substances, such as AMPK and calcium activated proteins, have been suggested as potential mediators but the exact mechanisms of their involvement remain to be elucidated. A hypothetical convergence point between the insulin cascade and the potential pathways triggered by muscle contraction has been suggested. Therefore, the earliest concept that two different routes exist in skeletal muscle has been progressively modified to the notion that glucose uptake is induced by muscle contraction via components of the insulin pathway. With further consideration, increased glucose uptake and enhanced insulin sensitivity observed during/after exercise might be explained by a metabolic- and calcium-dependent activation of several intermediate molecules of the insulin cascade. This paper aimed to review the literature in order to examine in detail these concepts behind muscle contraction-induced glucose uptake.

Evidences of apoptosis during the early phases of soleus muscle atrophy in hindlimb suspended mice.

The purpose of this study was to investigate the occurrence and time-course of apoptosis in soleus skeletal muscle during the first 48 hours of unloading. Fifty Charles River mice were randomly divided into five groups (n=10 each) according to the time of hindlimb suspension (HS). Mice were suspended for 0 (Control), 6 (6HS), 12 (12HS), 24 (24HS), and 48 hours (48HS). Soleus muscle atrophy was confirmed by a significant decrease of 20 % in muscle-wet weight and of 5 % in the ratio protein concentration/muscle wet-weight observed after 48 hours of unloading. The apoptotic index, the AIF (apoptosis-inducing factor) and p53 expression presented their uppermost value (304 %, 241 % and 246 %, respectively) at 24HS, and were preceded by the highest activity of caspase-3 and -8 at 12HS (170 % and 218 %, respectively) and of Bax/Bcl-2 content at 6HS (160 %). There were no marked ultrastructural alterations until 24 hours of simulated weightlessness. Lysosomal autophagic activity and infiltration of phagocytic cells were observed at 24HS and 48HS and might have contributed to the degenerative changes noticed in both groups. Though not consistently supported by morphological evidences, the biochemical parameters sustain the concept that the occurrence of apoptosis parallels the soleus atrophic response in its early phase.

Gluteus medius muscle atrophy is related to contralateral and ipsilateral hip joint osteoarthritis.

In order to understand the role of the GLUTEUS MEDIUS muscle (GM) in hip joint osteoarthritis, the objective of this study was to analyze the correlation between morphometric data of GM samples with osteoarthritis scores of ipsilateral and contralateral hips in 41 patients. GM samples obtained during unilateral hip replacement surgery were used to evaluate muscle fibers in the cross-sectional area (CSA) and other features indicative for muscle aging. Clinical symptoms were assessed by the Lequesne pain score. Hip osteoarthritis was graded by the Kellgren score and by measuring the sum joint space width (sumJSW) at three different articular locations and minimal JSW in a. p. radiographs. Varying degrees of GM muscle atrophy correlated with the pain score; pain score also correlated with radiographic signs of osteoarthritis. GM CSA was significantly correlated with all radiographic signs of the contralateral hip, but only with the sumJSW in the ipsilateral hip. It can be concluded that a weak GM may be the result of ipsilateral osteoarthitis, but may especially predispose the contralateral hip to develop osteoarthritis. This can be associated with an impaired GM capacity to avoid the shock impact in the load transfer during gait. Muscle strengthening is therefore recommended.

Acute effects of stretching on muscle stiffness after a bout of exhaustive eccentric exercise.

With the aim to analyze the influence of stretching on muscle stiffness after eccentric exercise, 30 young men (18 - 32 years old), were divided into three groups: STR, undergoing a stretching program (SP) of the dominant quadriceps muscle, ECC, undergoing exhaustive eccentric exercise, and ECC/STR, undergoing eccentric exercise, followed by SP. Muscle stiffness (MS) was assessed immediately before the respective programs, and 1 and 24 hours after, measuring the following parameters during Wartenberg pendulum test: angle and angular velocity of first knee flexion (FKF) and following oscillating extension, time of oscillating movements and final resting knee angle (FRKA). Despite the slight (2%) but significant increase of FRKA, all further parameters did not change over time in STR. MS in ECC was documented by the reduced range of motion (ROM) and the slower angular velocity. Reduction in FRKA (10%) was still present after 24 hours, while other variables tended to recover eventually. Similar reduction in FKF was observed for ECC/STR, but with significantly less impairment in the range of pendulum movement one hour after the exercise and in tendency still remained less impaired 24 hours after. The results suggest that SP conducted after exhaustive eccentric exercise alleviated reductions in ROM induced by exercise.

Exhaustive exercise with high eccentric components induces prothrombotic and hypofibrinolytic responses in boys.

It is known that coagulation and fibrinolysis are activated after exercise, and that the response is related to exercise intensity. The contribution, however, of eccentric exercise has not yet been investigated. Twenty boys (age 13 years) were randomly assigned to two experimental groups, which had to perform a monopedal stepping exercise until exhaustion. One group had to step up and down (U/D) in the same rhythm of one second each, while the other group (U/DD) had to step up during one second and to step down during two seconds, thereby experiencing a higher eccentric load. Blood samples were collected before and at 0, 1, and 24 hrs after exercise, and F VIII, t-PA, PAI-1, and D-dimer were determined as markers for coagulation or fibrinolysis, respectively. While the tendency for hypercoagulability was counterbalanced by fibrinolysis in the U/D group, the U/DD group showed a prothrombotic and hypofibrinolytic hemostatic response. It is assumed that eccentric exercise, beyond the well-known muscle fiber damage, also leads to some damage of the endothelial cells, affecting their capacity to liberate sufficient amounts of fibrinolytic agents.

Proposal for classification of the suprascapular notch: a study on 423 dried scapulas.

The present study proposes a simple and reproducible method to classify the morphology of the suprascapular notch (SSN), on the basis of specific geometrical parameters that clearly distinguish one type from another. Four hundred twenty-three dried scapulas from the Department of Anatomy in the University of Cologne, Germany, were examined. Five types of SSN were observed: type I, without a discrete notch, 35 (8.3%); type II, a notch that was longest in its transverse diameter, 177 (41.85%); type III, a notch that was longest in its vertical diameter, 177 (41.85%); type IV, a bony foramen, 31 (7.3%); type V, a notch and a bony foramen, 3 (0.7%). For the vertical diameter, we took the maximal diameter of the notch perpendicular to the imaginary line that joins the two superior corners of the notch. For the transverse diameter, we took the diameter perpendicular to the midpoint of the vertical diameter. This classification based on the vertical and the transverse diameters of the SSN suggested a clear distinction of the notch types. This simple classification included all the anatomical variations of the SSN. Using this method, the clinician will be able to define easily and quickly the notch type on a plain radiograph, and perhaps be able to correlate suprascapular nerve entrapment with a specific type of SSN.

Hemostatic response to acute physical exercise in healthy adolescents.

The chronic and immediate post-exercise responses in the hemostatic and fibrinolytic systems have been shown to be variable and reflect differing adaptations with ageing and responses to exercise protocols. This study investigated the effects of acute and exhaustive exercise on the amplitude and duration of hemostatic and fibrinolytic responses in young adolescent males. The sample comprised 10 sedentary boys (13.2+/-0.5 years, 55.8+/-11.3kg, 165.7+/-7.4cm), who had not exercised or received any medication for at least 2 weeks before the experiments. The subjects performed exhaustive stepping exercise, consisting of 1s up and down cycles to fatigue. When the subjects were unable to maintain the required stepping rhythm, they were given a 30s recovery period. Following each 30s recovery participants recommenced the stepping cadence until fatigue prevented them continuing. Venous blood samples were drawn before and immediately, 1 and 24h after exercise to assess the following coagulation and fibrinolytic parameters: Platelet counts, activated partial thromboplastin time (aPTT), prothrombin time (PT), coagulation factor VIII (FVIII:C), von Willebrand factor (vWF), fibrinogen concentration, thrombin-antithrombin complex (TAT), D-dimer, plasminogen activator inhibitor (PAI-1), and tissue-type plasminogen activator (t-PA). Immediately following exercise, platelet counts, aPTT, FVIII, vWF and t-PA were significantly elevated in contrast to PAI-1, which decreased significantly until 1h after exercise. FVIII and platelet counts were elevated at 1 and 24h after exercise, respectively. Only the parameters FVIII and PAI-1 did not return to baseline values during the first hour after physical exercise. When compared to adults the results revealed different rates and ranges of coagulation and fibrinolysis parameters being activated by exhaustive exercise in this group of adolescents.

Correlation between the four types of acromion and the existence of enthesophytes: a study on 423 dried scapulas and review of the literature.

The purpose of this study was to correlate the four types of acromial shape with the existence of enthesophytes, which together comprise two important parameters for subacromial impingement syndrome and rotator cuff tears. In addition, a review of the literature was carried out. Four hundred twenty-three dried scapulas were studied at the Department of Anatomy in the University of Cologne, Germany. Four types of acromion were found: the three classical ones as described by Bigliani et al. ([1986] Orthop Trans 10:216) and a fourth one, where the middle third of the undersurface of acromion was convex (Gagey et al. [1993] Surg Radiol Anat 15:63-70). The correlation between the four types of acromion and the presence of enthesophytes at its anterior undersurface was also recorded. The distribution of acromial types was as follows: type I, flat, 51 (12.1%); type II, curved, 239 (56.5%); type III, hooked, 122 (28.8%); and type IV, convex, 11 (2.6%). Enthesophytes were found in 1 of type I (2%), in 19 of type II (7.9%), in 46 of type III (37.7%), and in 0 (0%) of type IV acromions. Overall, 66 (15.6%) out of 423 scapulas had enthesophytes. In all cases, they were localized at the site of the coracoacromial ligament insertion on the acromion. Enthesophytes were significantly (P < 0.05) more common in type III acromions and this combination is particularly associated with subacromial impingement syndrome and rotator cuff tears. In type I and in type IV acromions, the incidence of enthesophytes is very small and, according to other studies, with these two acromial types rotator cuff tears are also rare.

The course of the greater occipital nerve in the suboccipital region: a proposal for setting landmarks for local anesthesia in patients with occipital neuralgia.

The anatomical relationships of the greater occipital nerve (GON) to the semispinalis capitis muscle (SCM) and the trapezius muscle aponeurosis (TMA) were examined to identify topographic landmarks for use in anesthetic blockade of the GON in occipital neuralgia. The course and the diameter of the GON were studied in 40 cadavers (29 females, 11 males), and the points where it pierced the SCM and the TMA were identified. The course of the GON did not differ between males and females. A left-right difference was detected in the site of the GON in the TMA region but not in the SCM region. The nerve became wider towards the periphery. This may be relevant to entrapment of the nerve in the development of occipital neuralgia. In three cases, the GON split into two branches before piercing the TMA and reunited after having passed the TMA, and it pierced the obliquus capitis inferior muscle in another three cases. The GON and the lesser occipital nerve reunited at the level of the occiput in 80% of the specimens. The occiput and the nuchal midline are useful topographic landmarks to guide anesthetic blockade of the GON for diagnosis and therapy of occipital neuralgia. The infiltration is probably best aimed at the site where the SCM is pierced by the GON.

Cardiac mitochondrial respiratory function and oxidative stress: the role of exercise.

Investigations on the mechanisms capable of influencing heart mitochondrial function constitute a central contribution to the understanding of cardiac bioenergetics. In contrast to the conventional idea that reactive oxygen species (ROS) mostly act as a trigger for oxidative damage of biological structures, in low physiological concentrations they can regulate a variety of important molecular mechanisms, including those related to mitochondrial respiratory function. Among others, moderate physical exercise seems to be an important agent to induce cellular and mitochondrial environmental redox modifications and it is possible that these alterations could mediate cardiac mitochondrial respiration patterns. This brief review summarizes some current knowledge on mitochondrial respiratory pathways and focuses on data provided by studies dealing with exercise and cardiac respiratory mechanisms. It is emphasized the need of further experimental studies that analyze the association between physical exercise, particularly endurance training, and several mechanisms hypothetically related to the improvement of mitochondrial function, such as the overexpression of some important chaperone machinery and the up-regulation of both cellular and mitochondrial antioxidants. The influence of chronic moderate exercise on the functionality of some inner membrane components and on mitochondrial calcium loading capacity remains to be established.

Treatment of muscle injuries by local administration of autologous conditioned serum: animal experiments using a muscle contusion model.

Muscle contusions represent a major part of sports injuries. The suggested treatments are generally sufficient to support muscle healing, but require a relatively long period of time. Given that autologous blood products are safe treatments, we have used a technique which stimulates the release of certain growth factors in the autologous conditioned serum (ACS). Those growth factors are known to improve the proliferative activity of myogenic precursor cells. Mice were subjected to an experimental contusion injury to their gastrocnemius muscle; one group received local injections of ACS at 2 hrs, 24 hrs, and 48 hrs after injury, a control group received saline injections. The histology results showed that satellite cell activation at 30/48 hrs post injury was accelerated and the diameter of the regenerating myofibers was increased compared to the controls within the first week after injury. ELISA results on the ACS have shown that the elevations in FGF-2 (460 %) and TGF-beta1 (82 %) could be partly responsible for the accelerating effects on regeneration due to proliferative and chemotactic properties. We conclude that ACS injection is a promising approach to reduce the time of recovery from muscle injury. In terms of clinical targets, this new approach could be used in the treatment of sports injuries and may also be interesting in postoperative situations.

Treatment of muscle injuries by local administration of autologous conditioned serum: a pilot study on sportsmen with muscle strains.

Muscle injuries represent a major part of sports injuries and are a challenging problem in traumatology. Strain injuries are the most common muscle injuries after contusions. These injuries can lead to significant pain and disability causing time to be lost to training and competition. Despite the frequency of strain injuries the treatment available is limited and is generally not sufficient to enhance muscle regeneration efficiently when fast resumption of sport activity is a primary target. A number of growth factors play a specific role in regeneration and it has been proven that a previously described method of physically and chemically stimulating whole blood (to produce autologous conditioned serum) induces concentration increases in FGF-2, HGF, and TGF-beta1. A preliminary study was conducted on muscle strain injuries in professional sportsmen receiving either: 1. autologous conditioned serum (ACS) or 2. Actovegin/Traumeel treatment as control. Assessment of recovery from injury was done by: 1. sport professional's ability to participate to 100 % under competition conditions in their respective sport and 2. MRI analysis. A significant difference in the recovery time from injury was demonstrated: 16.6 +/- 0.9 in the ACS treated instead of 22.3 +/- 1.2 (mean +/- SEM) days in the Actovegin/Traumeel control group (p = 0.001). MRI analysis supported the observed acceleration of the lesion recovery time. We conclude that ACS injection is a promising approach to reduce the time to recovery from muscle injury.

D-amphetamine-induced hydrogen peroxide production in skeletal muscle is modulated by monoamine oxidase inhibition.

The aim of this paper was to study the influence of d-amphetamine administration as a sympathomimetic drug on the synthesis of hydrogen peroxide (H2O2) in mouse soleus muscle and to investigate the modulating effects of pargyline, an inhibitor of monoamine oxidase (MAO) in this context. Charles River mice were assigned to four groups: Control, d-amphetamine treated, pargyline treated, and amphetamine + pargyline treated. Their soleus muscles were removed 0, 15, 30, 60, and 120 min after treatment. The amount of hydrogen peroxide formation within the muscles was estimated using an indirect method. The control data showed a continuous production of hydrogen peroxidase. Pargyline administration lead to an initial increase of H2O2 production that later faded below control levels. Administration of amphetamine finally stimulated H2O2 production much above control levels. When combining amphetamine and pargyline treatment, H2O2 production was accelerated in the initial phase but dropped to control levels at 30 min. It is concluded that in skeletal muscle MAO is an important source of hydrogen peroxide production triggered by amphetamine administration and that this tissue plays a hitherto not described role in oxidizing circulating biogenic monoamines.

Shoulder rotation characteristics in professional tennis players.

Aim of this study was to assess the glenohumeral joint internal and external rotational range of motion using an ultrasound based kinematic measurement device. Twenty-seven male professional tennis players were bilaterally measured for internal and external rotation at 90 degrees of shoulder abduction while avoiding scapulothoracic motion. The control group consisted of 20 asymptomatic volunteers not involved in overhead sports activities. The dominant arm (playing arm) had a significantly greater range of external rotation than the non-dominant arm, while their internal rotation showed a significant deficit as compared to the non-dominant arm. The dominant arm total rotational range of motion was also significantly reduced in comparison to the non-dominant arm and to the controls. No significant difference was found between the dominant and non-dominant extremity in the control group. For objective measurement of glenohumeral rotational range of motion ultrasound based real time motion analysis is a new application for the diagnostic testing of specific shoulder parameters in orthopedics and sports physical therapy. It is therefore concluded that the specific methodology aiming at isolated glenohumeral motion may have clinical application for the development of rehabilitation and preventative programs.

Characteristics of the gluteus medius muscle in an asymptomatic patient with radiographic signs of coxarthrosis.

This case study describes the micromorphology and some biochemical features of gluteus medius muscle in a 79-year-old woman with radiographic signs of coxarthrosis but with no clinical symptoms who initially was admitted in the orthopaedic emergency service with a non-displaced subcapital fracture of the femoral neck due to a domestic accident (fall). The X-ray of the hip showed some characteristic features of coxarthrosis, classified grade 2 of the Kellgren criteria. After informed consent, it was decided to carry out the functional evaluation according to the indexes of Lequesne and WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) and to take a biopsy of the gluteus medius muscle for microscopical examination and myosin heavy chain isoform identification during hip replacement surgery. For the Lequesne Index (score 0-24), the total score was 0, and for the WOMAC (score 0-96), the total score was also 0, both speaking in favour of full joint and muscle function. All the structural features observed in muscle were considered not to have any pathological relevance. The composition of the myosin heavy chains in the gluteus medius muscle was 48% MHC I, 41% MHC IIa, and 11% MHC IIx. The muscle characteristics do not support earlier concepts about muscle weakness as a predisposing factor for osteoarthritis. It is moreover concluded that the diagnosis should rather consider clinical symptoms than radiographic signs of osteoarthritis.