Ejnar Eriksson

Hamstring Injuries in Sprinters The Role of Concentric and Eccentric Hamstring Muscle Strength and Flexibility

Eleven sprinters with recent hamstring injuries were compared with nine uninjured runners. The flexibility of the hamstrings and the eccentric and concentric muscle torque were measured in the hamstrings and quadriceps muscles at different angular velocities. Sprinters with a previous hamstring injury had signifi cantly tighter hamstrings than uninjured sprinters had. The uninjured sprinters had significantly higher eccen tric hamstring torques at all angular velocities. They also had significantly higher concentric quadriceps and hamstring torques at 30 deg/sec but not at higher velocities. Sprinters with a history of hamstring injury thus differed from uninjured runners, being weaker in eccentric contractions and in concentric contractions at low velocities.

Comparison of isometric muscle training and electrical stimulation supplementing isometric muscle training in the recovery after major knee ligament surgery A preliminary report

Eight patients undergoing reconstruction of the anterior cru ciate ligament were randomly allocated into two groups. The control group received a standard plaster cast and isometric muscle training. The stimulated group received a standard plaster cast, isometric training, and percutaneous electrical stimulation during the recovery period. The patients were examined clinically and with repeated muscle biopsies before surgery, 1 week after surgery, and 5 weeks after surgery at the time of removal of the cast. The electrically stimulated group had better muscle function from a clinical point of view and their succinate dehydrogenase activities were significantly higher than those in the control group. Electrical stimulation thus could prevent the fall in oxidative enzyme activity which was noted in the control group. The results suggest that percutaneous electrical stimulation may be a way of preventing muscle atrophy after major knee ligament surgery in athletes.

Calf muscle atrophy and muscle function after non-operative vs operative treatment of achilles tendon ruptures

Fifteen operatively and eight non-operatively treated subcutaneous achilles tendon ruptures were randomly selected from 120 surgically and 35 non-surgically treated patients. Their calf muscle function was studied three to five years after treatment. Non-operatively treated patients were found to have a significantly impaired dynamic muscle function of the calf muscles when tested in a specially constructed heel-raise test device. Operatively treated patients did not show any significant impairment of their muscle function. Measurement of muscle area with CT-scanning showed a significant reduction of the calf muscle in the non-operatively treated patient while no such difference could be found in the operatively treated patients. Isokinetic muscle torque did not differ in the two groups of patients, thus Cybex-measurements do not seem to be a discriminating method in studying muscle function after achilles ruptures. On the basis of our findings we recommend that all athletes with achilles tendon ruptures be treated surgically. In non-athletes and older patients non-operative treatment might be considered.

Cylinder or mobile cast brace after knee ligament surgery. A clinical analysis and morphologic and enzymatic studies of changes in the quadriceps muscle.

Sixteen patients participated in a prospective randomized trial in which a standard cylinder cast was compared with a mobile cast brace. Both were worn for 4 weeks, beginning at 1 week after reconstruction of the anterior cruciate ligament. The athletes that had used a cast brace could return to sports activities in about one-half the time it took for the athletes with a standard cast. The patients with a standard cast showed a significant atrophy of Type I (slow twitch) muscle fibers in the vastus lateralis. The cast brace patients did not show any significant changes in cross-sectional areas of Type I or Type II (fast twitch) muscle fibers. The standard cast patients had a significant reduction of succinate dehydrogenase (SDH) activity in the vastus lateralis whereas the patients with the cast brace did not show any significant changes. No difference in surgical end result was found. A cast brace with a limited range of motion between 20 and 60° of flexion is recommended as the standard postopera tive treatment after knee ligament surgery.

Hypotrophy of the soleus muscle in man after Achilles tendon rupture Discussion of findings obtained by computed tomography and morphologic studies

Seven athletes (age range, 35 to 43 years), who sustained total subcutaneous ruptures of the Achilles tendon 2 to 5 cm above its distal insertion, were treated surgically with suturing of the tendon, immobilization of the leg and foot for 6 weeks, and cast changes so as to increase the dorsiflexion of the foot. Needle biopsies were obtained several times from the soleus muscles of both the injured and uninjured legs at a depth of about 5 cm. The cross-sectional area was measured by computed tomogra phy at the same level the tissue was obtained by biopsy. Results of morphologic studies revealed a selective Type I fiber atrophy of the soleus muscle. Computed tomography revealed a 23% decrease in the area of the calf muscles and a 11% total reduction in the cross-sectional area of the calf (about the middle, where the gastrocnemius muscle is transformed into a tendon and where the soleus lies superficially). Mere measure ment of the circumference of the calf is judged to be a poor criterion of muscle atrophy when compared with these other means of evaluation of atrophy. The evidence compiled during this study suggests that prompt surgical treatment of Achilles tendon ruptures, with cast changes several times during the period of immobilization and with tension maintained on the muscle, is the most effective treatment regimen we have found for this injury.

Prevention of Quadriceps Wasting After Immobilization: An Evaluation of the Effect of Electrical Stimulation

Eighteen male and 20 female patients who underwent reconstruction of their anterior cruciate ligament (ACL) with a flap from the patellar tendon were randomly assigned into either closed cast, isometric muscle training and electric stimulation (ES group), or closed cast and isometric training alone (control group). The degree of quadriceps wasting was determined from computerized tomographic scans (CT) before and 6 weeks after surgery. Electrical stimulation was given with a battery operated stimulator that produced a rectangular asymmetric balanced biphasic pulse shape. The pulse rate was 40 Hz and the pulse width 300 microseconds. Patients received 30 min of stimulation three times daily during 5.5 weeks. Female control patients showed a larger decrease in quadriceps area on CT than male control patients (P less than .001). No significant difference was found between male electrically stimulated patients and control patients. In female patients, there was on the contrary, a highly significant difference in favor of electrical stimulation (P less than .001) When the different parts of the quadriceps were studied, a significantly lower degree of atrophy of the vastus medialis was found after electrical stimulation. Vastus lateralis did not show any difference. Measurements of CT attenuation, pre- and post-operatively, showed a decrease in attenuation of 17% for the vastus medialis and lateralis of the operated leg after immobilization, indicating an increase in fat content. In the rectus femoris, however, there was an increase in attenuation of 14.6%. Percutaneous muscle biopsies from the vastus lateralis obtained before, one week after, and 6 weeks after surgery revealed that the cross-sectional area of the individual muscle fibers decreased less in the electrically stimulated than in controls, but the difference was not significant. There were no differences between the two groups in the activity of an oxidative enzyme, citrate synthase, or a glycolytic enzyme, phosphofructokinase (PFK). We conclude that females reacted more favorably than males to electrical stimulation of quadriceps during an immobilization period after knee surgery.

Muscle fiber type changes in human skeletal muscle after injuries and immobilization

Eight athletes operated on for knee injuries were followed with muscle biopsies before and at various intervals after surgery and immobilization. A statistically significant change of the muscle fiber distribution was found. The percentage type I fibers dropped from an average of 54% to 43%. One competitive cross-country skier showed a dramatic drop from 81% type I fibers at surgery to 58% type I fibers six weeks later. After beginning training he returned to 85% type I fibers. One athlete who had been operated and immobilized for long periods several times showed a drastic difference in fiber type distribution between his two thighs with 20% type I fibers in the injured leg and 69% type I fibers in his uninjured leg. After three years of training his fiber type composition in the injured leg returned toward the fiber type distribution of the uninjured thigh. It is evident that muscle fiber type composition can change. The most probable reason for this is that the drastic change from hard sports training to nearly complete immobilization influences both the muscle itself and its innervation and causes this change of fiber types.

Amplitude and timing of electromyographic activity during sprinting

The aim of this study was to make descriptive analyses of the muscle activities in the lower extremity during maximal sprinting. Nine healthy sprinters were examined during maximal sprinting using telemetric electromyography (EMG). Seven muscles of the lower extremities were investigated: biceps femoris, medial hamstrings (semimembranosus and semitendinosus), rectus femoris, gluteus maximus, tibialis anterior, lateral gastrocnemius and medial gastrocnemius. The recorded EMG levels during running were expressed as percentage of maximum voluntary isometric contractions (%max EMG). For each muscle, the normalized EMG was plotted during the whole running stride cycle and is presented for each muscle. The reason for using this method is to show that it is possible to compare different muscle activities in a runner as well as to make comparisons between runners. Lateral and medial hamstrings and gluteus maximus showed similar activities with peak levels of EMG during footstrike. Rectus femoris had a two‐peak activity, with one peak at the middle of the stance phase and the other during the swing phase. The tibialis anterior also showed a two‐peak activity, but with the peaks at the beginning of the swing phase and just before foot‐strike. The highest activities of the medial and lateral gastrocnemius occurred just before toe‐off.

Does amateur boxing lead to chronic brain damage? A review of some recent investigations

Fifty former amateur boxers were examined and com pared with two control groups of soccer players and track and field athletes. All subjects were interviewed regarding their sports career, medical history, and so cial variables. They underwent a physical and a neuro logic examination. Personality traits were investigated and related to the platelet monoamine oxidase activity. Cerebral morphologic changes were evaluated using computed tomography and magnetic resonance imag ing. Further, clinical neurophysiologic tests were made as well as neuropsychologic tests. No significant differences were found between the groups in any of the physical or neurologic examinations or in platelet monoamine oxidase activity. Socially, the boxers had a lower degree of education and had cho sen less intellectual professions, but they were less impulsive and more socialized. The computed tomog raphy images and magnetic resonance imaging studies showed no significant differences between the groups. There was a significantly higher incidence of slight or moderate electroencephalography deviations among the boxers. Neuropsychologically, the boxers had an inferior finger-tapping performance. Thus, no signs of serious chronic brain damage were found among any of the groups studied. However, the electroencepha lography and finger-tapping differences between the groups might indicate slight brain dysfunction in some of the amateur boxers.

Knee Arthroscopy With Local Anesthesia in Ambulatory Patients: Methods, Results and Patient Compliance

Knee arthroscopy in locally anesthetized ambulatory patients has been performed by filling the knee joint with 50 ml to 60 ml of 0.5% prilocaine, with adrenaline and with additional local infiltration at the sites of puncture. During the arthroscopic procedure the joint cavity is further distended with a mixture of the same local anesthetic diluted 1:10 with physiological saline or Ringers acetate. During a normal arthroscopy of the knee joint about 500 mg of the local anesthetic is used. In 17 patients the blood concentrations of the local anesthetic used was measured 2.5 min to 135 min after instillation. The highest plasma levels found (after 60 min to 120 min) were still 10 to 15 times lower than an acceptable upper plasma level. These low blood levels probably depend on a slow absorption and that a considerable amount of the local anesthetic is washed out after the arthroscopy. A questionnaire was sent to 278 patients who during a two year period had undergone arthroscopy as an outpatient procedure. The degree of satisfaction for the anesthetic procedure was highest for general anesthesia where 97% were completely satisfied. Sixty-four percent were satisfied when given spinal anesthesia. However, 11% had to be put to sleep due to insufficient spinal block and 12% had headaches more than one day after outpatient spinal anesthesia. Seventy-seven percent were satisfied with local anesthesia. There was no statistical difference between the degree of satisfaction after local or spinal anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)