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Dive into the research topics where Ronny Lorentzon is active.

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Featured researches published by Ronny Lorentzon.


American Journal of Sports Medicine | 1998

Heavy-Load Eccentric Calf Muscle Training For the Treatment of Chronic Achilles Tendinosis

Håkan Alfredson; Tom Pietilä; Per Jonsson; Ronny Lorentzon

We prospectively studied the effect of heavy-load eccentric calf muscle training in 15 recreational athletes (12 men and 3 women; mean age, 44.3 7.0 years) who had the diagnosis of chronic Achilles tendinosis (degenerative changes) with a long duration of symptoms despite conventional nonsurgical treatment. Calf muscle strength and the amount of pain during activity (recorded on a visual analog scale) were measured before onset of training and after 12 weeks of eccentric training. At week 0, all patients had Achilles tendon pain not allowing running activity, and there was significantly lower eccentric and concentric calf muscle strength on the injured compared with the noninjured side. After the 12-week training period, all 15 patients were back at their preinjury levels with full running activity. There was a significant decrease in pain during activity, and the calf muscle strength on the injured side had increased significantly and did not differ significantly from that of the noninjured side. A comparison group of 15 recreational athletes with the same diagnosis and a long duration of symptoms had been treated conventionally, i.e., rest, nonsteroidal antiinflammatory drugs, changes of shoes or orthoses, physical therapy, and in all cases also with ordinary training programs. In no case was the conventional treatment successful, and all patients were ultimately treated surgically. Our treatment model with heavy-load eccentric calf muscle training has a very good short-term effect on athletes in their early forties.


British Journal of Sports Medicine | 2004

Eccentric training in patients with chronic Achilles tendinosis: normalised tendon structure and decreased thickness at follow up

Lars Öhberg; Ronny Lorentzon; Håkan Alfredson

Objective: To prospectively investigate tendon thickness and tendon structure by ultrasonography in patients treated with eccentric calf muscle training for painful chronic Achilles tendinosis located at the 2–6 cm level in the tendon. Methods: The patients were examined with grey scale ultrasonography before and 3.8 years (mean) after the 12 week eccentric training regimen. At follow up, a questionnaire assessed present activity level and satisfaction with treatment. Results: Twenty six tendons in twenty five patients (19 men and six women) with a mean age of 50 years were followed for a mean of 3.8 years (range 1.6–7.75). All patients had a long duration of painful symptoms (mean 17.1 months) from chronic Achilles tendinosis before treatment. At follow up, 22 of 25 patients were satisfied with treatment and active in Achilles tendon loading activities at the desired level. Ultrasonography showed that tendon thickness (at the widest part) had decreased significantly (p<0.005) after treatment (7.6 (2.3) v 8.8 (3) mm; mean (SD)). In untreated normal tendons, there was no significant difference in thickness after treatment (5.3 (1.3) mm before and 5.9 (0.8) mm after). All tendons with tendinosis had structural abnormalities (hypoechoic areas and irregular structure) before the start of treatment. After treatment, the structure was normal in 19 of the 26 tendons. Six of the seven patients with remaining structural abnormalities experienced pain in the tendon during loading. Conclusions: Ultrasonographic follow up of patients with mid-portion painful chronic Achilles tendinosis treated with eccentric calf muscle training showed a localised decrease in tendon thickness and a normalised tendon structure in most patients. Remaining structural tendon abnormalities seemed to be associated with residual pain in the tendon.


Sports Medicine | 2000

Chronic Achilles tendinosis: recommendations for treatment and prevention.

Håkan Alfredson; Ronny Lorentzon

Chronic Achilles tendinosis is a condition with an unknown aetiology and pathogenesis that is often, but not always, associated with pain during loading of the Achilles tendon. Histologically, there are no inflammatory cells, but increased amounts of interfibrillar glycosaminoglycans and changes in the collagen fibre structure and arrangement are seen. In situ microdialysis has confirmed the absence of inflammation. It is a condition that is most often seen among recreational male runners aged between 35 and 45 years, and it is most often considered to be associated with overuse. However, this condition is also seen in patients with a sedentary lifestyle.Chronic Achilles tendinosis is considered a troublesome injury to treat. Nonsurgical treatment most often includes a combination of rest, NSAIDs, correction of malalignments, and stretching and strengthening exercises, but there is sparse scientific evidence supporting the use of most proposed treatment regimens. It has been stated that, in general, nonsurgical treatment is not successful and surgical treatment is required in about 25% of patients. However, in a recent prospective study, treatment with heavy load eccentric calf muscle training showed very promising results and may possibly reduce the need for surgical treatment of tendinosis located in the midportion of the Achilles tendon.The short term results after surgical treatment are frequently very good, but in the few studies with long term follow-up there are signs of a possible deterioration with time. Calf muscle strength takes a long time to recover and, furthermore, a prolonged progressive calcaneal bone loss has been shown on the operated side up to 1 year after surgical treatment.


Knee Surgery, Sports Traumatology, Arthroscopy | 1999

In situ microdialysis in tendon tissue : high levels of glutamate, but not prostaglandin E2 in chronic Achilles tendon pain

Håkan Alfredson; Kim Thorsen; Ronny Lorentzon

Abstract This investigation was to our knowledge the first to use the microdialysis technique to study concentrations of substances in a human tendon. In four patients (mean age 40.7 years) with a painful nodule in the Achilles tendon (chronic Achilles tendinosis) and in five controls (mean age 37.2 years) with normal Achilles tendons (confirmed by ultrasonography) the local concentrations of glutamate and prostaglandin E2 were measured under resting conditions. A standard microdialysis catheter was inserted into the Achilles tendon under local anesthesia. Sampling was performed every 15 min over a 4-h period. The results showed significantly higher concentrations of glutamate in tendons with tendinosis than in normal tendons (196 ± 59 vs. 48 ± 27 μmol/l, P < 0.05), and there were no significant changes in glutamate concentration over the period of investigation. There were no significant differences in the mean concentrations of prostaglandin E2 (83 ± 22 vs. 54 ± 24 pg/ml) between tendons with tendinosis and normal tendons. In conclusion, in situ microdialysis appears a useful method to study certain metabolic events in tendon tissue. The higher concentrations of the excitatory neurotransmitter glutamate in Achilles tendons with a painful nodule may possibly be involved in the pain mechanism in this chronic condition. Furthermore, there were no signs of inflammation in the tendons with painful nodules, as indicated by the normal prostaglandin E2 levels.


Journal of Orthopaedic Research | 2001

In vivo microdialysis and immunohistochemical analyses of tendon tissue demonstrated high amounts of free glutamate and glutamate NMDAR1 receptors, but no signs of inflammation, in Jumper's knee.

Håkan Alfredson; Sture Forsgren; Kim Thorsen; Ronny Lorentzon

This investigation describes, to our knowledge, the first experiment where the microdialysis technique was used to study certain metabolic events in human patellar tendons in combination with immunohistochemical analyses of tendon biopsies. In five patients (four men and one woman) with a long duration (range 12‐36 months) of pain symptoms from Jumpers knee (localized tenderness in the patellar tendon verified as tendon changes with ultrasonography or MRI), and in five controls (four men and one woman) with normal patellar tendons, a standard microdialysis catheter was inserted into the patellar tendon under local anestesia. The local concentrations of glutamate (excitatory neurotransmitter) and prostaglandin E2 (PGE2) were registered under resting conditions. Samplings were done every 15 min during a 2 h period. In all individuals (patients and controls) biopsies were taken for immunohistochemical analyses.


British Journal of Sports Medicine | 2004

A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy

Craig Purdam; Per Jonsson; Håkan Alfredson; Ronny Lorentzon; J. Cook; Karim M. Khan

Objectives: This non-randomised pilot study investigated the effect of eccentric quadriceps training on 17 patients (22 tendons) with painful chronic patellar tendinopathy. Methods: Two different eccentric exercise regimens were used by subjects with a long duration of pain with activity (more than six months). (a) Nine consecutive patients (10 tendons; eight men, one woman; mean age 22 years) performed eccentric exercise with the ankle joint in a standard (foot flat) position. (b) Eight patients (12 tendons; five men, three women; mean age 28 years) performed eccentric training standing on a 25° decline board, designed to increase load on the knee extensor mechanism. The eccentric training was performed twice daily, with three sets of 15 repetitions, for 12 weeks. Primary outcome measures were (a) 100 mm visual analogue scale (VAS), where the subject recorded the amount of pain during activity, and (b) return to previous activity. Follow up was at 12 weeks, with a further limited follow up at 15 months. Results: Good clinical results were obtained in the group who trained on the decline board, with six patients (nine tendons) returning to sport and showing a significantly reduced amount of pain over the 12 week period. Mean VAS scores fell from 74.2 to 28.5 (p  =  0.004). At 15 months, four patients (five tendons) reported satisfactory results (mean VAS 26.2). In the standard squat group the results were poor, with only one athlete returning to previous activity. Mean VAS scores in this group were 79.0 at baseline and 72.3 at 12 weeks (p  =  0.144). Conclusion: In a small group of patients with patellar tendinopathy, eccentric squats on a decline board produced encouraging results in terms of pain reduction and return to function in the short term. Eccentric exercise using standard single leg squats in a similar sized group appeared to be a less effective form of rehabilitation in reducing pain and returning subjects to previous levels of activity.


Acta Orthopaedica Scandinavica | 2000

In vivo investigation of ECRB tendons with microdialysis technique--no signs of inflammation but high amounts of glutamate in tennis elbow

Håkan Alfredson; Björn-Ove Ljung; Kim Thorsen; Ronny Lorentzon

We used the microdialysis technique to study concentrations of substances in the extensor carpi radialis brevis (ECRB) tendon in patients with tennis elbow. In 4 patients (mean age 41 years, 3 men) with a long duration of localized pain at the ECRB muscle origin, and in 4 controls (mean age 36 years, 2 men) with no history of elbow pain, a standard microdialysis catheter was inserted into the ECRB tendon under local anesthesia. The local concentrations of the neurotransmitter glutamate and prostaglandin E 2 (PGE 2 ) were recorded under resting conditions. Samplings were done every 15 minutes during a 2-hour period. We found higher mean concentrations of glutamate in ECRB tendons from patients with tennis elbow than in w tendons from controls (215 vs. 69 _6;moL/L, p < 0.001). There were no significant differences in the mean concentrations of PGE 2 (74 vs. 86 pg/mL). In conclusion, in situ microdialysis can be used to study certain metabolic events in the ECRB tendon of the elbow. Our findings indicate involvement of the excitatory neurotransmitter glutamate, but no biochemical signs of inflammation (normal PGE 2 levels) in ECRB tendons from patients with tennis elbow.


Scandinavian Journal of Rheumatology | 1992

Muscle performance, electromyography and fibre type composition in fibromyalgia and work-related Myalgia

Jessica Elert; S. B. Rantapää-dahlqvist; Karin Henriksson-Larsén; Ronny Lorentzon; Björn Gerdle

Muscle performance and fibre type composition were investigated in women with fibromyalgia, work-related trapezius myalgia and healthy volunteers. Each subject performed 100 repetitive shoulder flexions using an isokinetic dynamometer during simultaneous registration of surface electromyography. A biopsy from the trapezius muscle was obtained. The groups differed neither in mechanical performance nor in fibre type proportions. An inability to relax between contractions was found in all registered muscles in patients with fibromyalgia. The patients with work-related myalgia displayed an inability to relax only in the myalgic trapezius muscle. An inability to relax during repetitive movements might play an important role both in initiating and upholding muscle pain.


Scandinavian Journal of Medicine & Science in Sports | 2001

Injuries in adolescent female players in European football: a prospective study over one outdoor soccer season

Kerstin Söderman; J Adolphson; Ronny Lorentzon; Håkan Alfredson

In this prospective study, injuries in 153 adolescent female soccer players were recorded during one outdoor season (April–October). The overall injury incidence rate was 6.8 per 1000 h soccer (games and practice) and the incidence rate of traumatic injury 9.1 and 1.5 per 1000 player‐hours in games and practice, respectively. Sixty‐three players (41%) sustained 79 injuries. Sixty‐six percent of the injuries were traumatic and 34% were overuse injuries. Most of the traumatic injuries occurred during games. Eighty‐nine percent of the injuries were located in the lower extremities and 42% occurred in the knee or ankle. The most frequent type of injury was ankle sprain (22.8%). Forty‐one percent of the traumatic injuries and 56% of the ankle sprains were re‐injuries. Most of the injuries were of moderate severity (52%), while 34% were minor and 14% were major. Most of the major injuries were traumatic such as knee ligament injuries and ankle sprains.


American Journal of Sports Medicine | 1988

Incidence, nature, and causes of ice hockey injuries A three-year prospective study of a Swedish elite ice hockey team

Ronny Lorentzon; Hans Wedren; Tom Pietilä

In this prospective study, we have investigated inci dence of injuries of different severity, types of injury, and mechanisms of injury during ice hockey practice and games. One Swedish elite hockey team was closely observed during three seasons (1982 to 1985). There was a total number of 95 injuries and 29 facial lacera tions. The majority of injuries were minor (73%) and only 8% were classified as major. Seventy-six percent of the injuries occurred during games and 24% during practice. The incidence of injury during practice was 1.4 per 1,000 player-practice hours and 78.4 per 1,000 player-game hours. In comparison with other sports, the incidence of injury during hockey practice is very low, while that during games is high. Eighty percent of the injuries were caused by trauma and 20% by over use. The most common types of injury were contusions, strains, and sprains. Complete tear of the medial col lateral ligament of the knee was the most common severe injury. Most injuries resulted from body contact, predominantly tackling (checking), and from puck or stick contact. A reduction of the number of minor and moderate injuries should be possible by stricter en forcement of the hockey rules, especially against stick violations, and more widespread use of visors.

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