1. |
- Oddsson, Asmundur, et al.
(author)
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Deficit of homozygosity among 1.52 million individuals and genetic causes of recessive lethality
- 2023
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Journal article (peer-reviewed)abstract
- Genotypes causing pregnancy loss and perinatal mortality are depleted among living individuals and are therefore difficult to find. To explore genetic causes of recessive lethality, we searched for sequence variants with deficit of homozygosity among 1.52 million individuals from six European populations. In this study, we identified 25 genes harboring protein-altering sequence variants with a strong deficit of homozygosity (10% or less of predicted homozygotes). Sequence variants in 12 of the genes cause Mendelian disease under a recessive mode of inheritance, two under a dominant mode, but variants in the remaining 11 have not been reported to cause disease. Sequence variants with a strong deficit of homozygosity are over-represented among genes essential for growth of human cell lines and genes orthologous to mouse genes known to affect viability. The function of these genes gives insight into the genetics of intrauterine lethality. We also identified 1077 genes with homozygous predicted loss-of-function genotypes not previously described, bringing the total set of genes completely knocked out in humans to 4785.
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2. |
- Brorsson, Annelie, 1963, et al.
(author)
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Injury Prevention in Basketball
- 2020
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In: Basketball Sports Medicine and Science. Laver L., Kocaoglu B., Cole B., Arundale A.J.H., Bytomski J., Amendola A. (eds). - Berlin, Tyskland : Springer-Verlag. - 9783662610695 ; , s. 657-663
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Book chapter (other academic/artistic)
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3. |
- Brorsson, Annelie, 1963, et al.
(author)
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The injured limb presents lower values in foot structure measurements 6 years after an achilles tendon rupture
- 2021
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In: Muscles, Ligaments and Tendons Journal. - : Edra SpA. - 2240-4554. ; 11:4, s. 694-703
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Journal article (peer-reviewed)abstract
- Background. It is not known if foot structure may change after an Achilles tendon rupture and if a possible change may have an impact on lower limb function. The primary aim of the study was to explore the difference in foot structure between injured and healthy limb and between two treatment groups, at mean 6 years after an Achilles tendon rupture. A secondary aim was to explore if the differences in foot structure correlated with functional and clinical outcome. Methods. Ninety patients (15 women) with the mean (SD) age of 49 (9) years were evaluated. They had all been randomized to be treated with (n = 45) or without (n = 45) surgery. Foot structure was evaluated with Navicular Drop (Ndrop) and Drift (Ndrift), Longitudinal Arch Angle (LAA) and standing Dorsiflexion with knee straight and bent (DFstraight) and (DFbent). Calf muscle performance was evaluated with Single-leg standing heel-rise test and tendon length with ultrasound. For Patient-reported outcome measurements, Achilles tendon Total Rupture Score (ATRS) and Physical Activity Scale (PAS) were used. Both limbs were evaluated and the limb symmetry index (LSI (%) = injured/healthy × 100) was calculated. Results. In all patients, the injured limb demonstrated lower values (injured/healthy) in Ndrift (6.0/6.7 mm, p = 0.034), Ndrop (6.6/7.4 mm, p = 0.32) and DFbent (44/46°, p < 0.001). In the group treated with surgery, there was significant difference between limbs in DFbent (44/46°, p = 0.002). In the non-surgically treated group, the injured limb demonstrated significantly lower values in Ndrift (6.0/7.4 mm, p = 0.005), Ndrop (6.9/8.2 mm, p = 0.005) and DFbent (44/46°, p = 0.008). There was no difference between treatment groups in LSI-values. Conclusions. An Achilles tendon rupture seems to have an impact on foot structure long time after the injury. There is a need to clarify if the injury influences both feet and if there is a difference between treatment groups.
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4. |
- Jonasson, G., et al.
(author)
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Effects of gender and fatigue on strength and activity of gluteus medius muscle during a controlled cutting maneuver in preadolescent athletes
- 2023
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In: Journal of Electromyography and Kinesiology. - 1050-6411. ; 70
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Journal article (peer-reviewed)abstract
- The present study aimed to investigate the effects of gender on hip muscle strength and activity during a controlled cutting maneuver in preadolescent athletes. Fifty-six football and handball preadolescent players participated (35 females and 21 males). Normalized mean activity of the gluteus medius (GM) muscle was measured using surface electromyography during cutting maneuvers in pre-activation and eccentric phases. The stance duration and the strength of hip abductors and external rotators were recorded with a force plate and a handheld dynamometer, respectively. Descriptive statistics and mixed model analysis were used to assess statistical difference (alpha = 0.05). The results showed that boys activate the GM muscle significantly more than girls during the pre-activation phase (P = 0.022). Boys also demonstrated greater normalized strength of hip external rotation than girls (P = 0.038), but not for hip abduction or duration of stance (P > 0.05). When adjusted for abduction strength, however, boys had significantly shorter stance duration than girls (P = 0.006). It seems that sex-dependent differences are present in preadolescent athletes as observed in the strength of hip external rotator muscles and neuromuscular activity of the GM muscle during a cutting maneuver. Future studies are needed to investigate whether these changes influence risk of lower limb/ACL injury during sport activities.
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5. |
- Jónsdóttir, Unnur Saedis
(author)
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Acute Achilles tendon rupture: The impact of physiological and psychological factors on function and return to activity
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Unfortunately, there is no guarantee of a full return to physical activity after an Achilles tendon rupture. About 20% of those who sustain the injury do not return to their previous level of physical activity. Although the reasons for this have been examined, no definitive conclusion has been reached. The main aim of this thesis was to gain knowledge of what can cause an incomplete recovery, which might negatively influence the return to physical activity. In this thesis, we try to identify interventions to eliminate the causes of incomplete recovery after an Achilles tendon rupture. In Study I foot structure was evaluated. We compared the uninjured and the injured sides 6 years after an Achilles tendon rupture. Two treatment groups (surgical and non-surgical) were also compared. Lower values for navicular drop and drift were found in the foot structure of the injured side in all participants, meaning that the translation of the navicular bone was less on the injured side compared with the uninjured side. The foot structure values (longitudinal arch angle and navicular drop and drift) were lower on the uninjured side in the surgically treated group compared with the non-surgical group, while there were no differences between the groups on the injured side. The effect of fatigue on the kinetics of the lower extremities was evaluated in Study II, two years after an Achilles tendon rupture. The peak power values of the ankle, knee and hip during landing and push-off for a drop countermovement jump were used for evaluation before and after a fatigue protocol. The results showed greater effect on the ankle joint after the fatigue protocol on the uninjured side compared with the injured side. However, there were no differences before and after the fatigue protocol in the knee and hip joints. In Study III, the impact of fear of reinjury on the kinetics in the lower extremities during a drop countermovement jump was evaluated 2 years after an Achilles tendon rupture. The participants were divided into two groups (Fear group and No-Fear group) depending on their answer to the question: “Do you ever refrain from any activity due to fear of reinjuring your Achilles tendon?”. The peak power values of the ankle, knee and hip joints during a drop countermovement jump were compared between the two groups. The results demonstrated increased asymmetry of the lower leg kinetics in the injured side in the Fear group, with less power in the ankle joint and increased compensatory power in the knee joint compared with the injured side in the No-Fear group. A qualitative content analysis was performed in Study IV, aimed at identifying factors that affect return to activity after an Achilles tendon rupture. Twenty participants were interviewed 4-6 years after an Achilles tendon rupture. The interviews were analysed and coded in order to categorize factors that collectively determine the thread/theme of the interviews. The overarching theme of the study was “Help me and then I can fix this”. This theme can be interpreted to the prerequisite that if the support one needs is in order, one can handle the next step. In summary, it is obvious that various physiological and psychological factors affect the return to activity. However, none of the factors examined in this thesis pointed the way towards a clear strategy. The effect of these factors appears to vary between individuals. It can thus be concluded that individualized treatment and rehabilitation are important, with frequent updates and evaluation of progress.
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6. |
- Jónsdóttir, Unnur Saedis, et al.
(author)
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Dissimilar limb symmetry effect of fatigue on ankle kinetics during single-leg drop jump two years after an Achilles tendon rupture.
- 2019
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In: Scandinavian Medicine Sports Congress, Köpenhamn 31/1-2/2 2019.
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Conference paper (other academic/artistic)abstract
- BACKGROUND Deficits in calf muscle performance and altered lower limb kinetics exist in patients after an Achilles tendon rupture (ATR). However, the influence of fatigue on functional performance is unclear. The aim of this study was to determine the effect of fatigue on a single-leg drop counter movement jump (drop CMJ) after an ATR. MATERIAL AND METHODS Twenty-seven subjects (22 male) with the mean (SD) age of 42.8 (9.3) years were evaluated 23.5 (8.4) months after ATR. Conventional motion capture procedures were used for data collection as participants performed drop CMJs before and after a standard fatigue protocol, consisting of bilateral single-leg standing heel-rise test followed by a 5-minute progressive slide board protocol. Data analysis focused on: a) eccentric and concentric ankle joint power (AJP); b) time from initial contact to peak eccentric and concentric AJP. RESULTS A significant limb by fatigue interaction was found for both eccentric (involved -0.83 W/kg; uninvolved -1.44 W/kg, p<0.001) and concentric AJP (involved -0.20 W/kg; uninvolved -0.71 W/kg, p<0.001), reflecting greater effects of fatigue on the uninvolved side. There was also significant difference in how fatigue delayed time to peak power during concentric (involved 15ms; uninvolved 29ms, p<0.001) but not eccentric AJP (p=0.854) CONCLUSION Fatigue had a greater effect on the uninvolved compared to the involved side. Since the uninvolved side seems to compensate for deficits in the involved side, there is a risk that the uninvolved side is more prone to injuries when returning back to sports after an ATR.
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7. |
- Jonsdottir, Unnur Saedis, 1982, et al.
(author)
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Factors That Affect Return to Sports After an Achilles Tendon Rupture: A Qualitative Content Analysis
- 2023
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In: Orthopaedic Journal of Sports Medicine. - : SAGE Publications. - 2325-9671. ; 11:1
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Journal article (peer-reviewed)abstract
- Background: Achilles tendon rupture is common among physically active individuals, yet a high percentage fail to return to their former activity after the injury. Quantifiable factors such as type of treatment, hours of rehabilitation, and age have not been associated with return-to-play rates. A factor that influences recovery is the participant’s experience before and throughout the rehabilitation process, which can be explored using a qualitative content analysis. Purpose: To explore and describe what influences the participant to return to physical activity after an Achilles tendon rupture. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty participants (14 men; mean age, 46 years) were interviewed as part of this study. All participants had ruptured their Achilles tendon 4 to 6 years before the interviews. From the interviews, codes were extracted that evolved into 19 subcategories, 6 categories, and 1 theme. Results: The overarching theme that emerged was “Help me and then I can fix this.” The 6 categories were (1) one’s own drive to succeed, (2) having a supportive social network, (3) trusting the support from the health and social systems, (4) receiving and adapting information from others drives persistence in returning to activity, (5) impact of the injury on psychological factors; and (6) influence of physiological aspects. Conclusion: To be able to recover properly from an Achilles tendon rupture and return to activity, the study participants described the importance of obtaining the support needed to be able to gain optimal rehabilitation. In the participants’ opinion, for a greater chance of successful treatment and rehabilitation, it was vital to be provided with good support.
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8. |
- Jónsdóttir, Unnur Saedis, et al.
(author)
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The effect of fear of reinjury on joint power distribution during a drop countermovement jump two years after an Achilles tendon rupture
- 2021
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In: Translational Sports Medicine. - : Hindawi Limited. - 2573-8488. ; 4:5, s. 667-674
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Journal article (peer-reviewed)abstract
- The incidence of Achilles tendon rupture (ATR) is increasing and at least 20% do not return to preinjury activity. The aim of the study was to evaluate biomechanical differences between those assigned to a Fear group and No-Fear group based on fear of reinjury during activity after ATR, by evaluating a drop countermovement jump. Twenty-five participants were evaluated 23.5 months after ATR. Peak values for eccentric and concentric joint power were identified for ankles, knees, and hips. Participants were assigned to Fear group or No-Fear group depending on their answers to a question regarding fear of reinjury during activities. Interlimb peak power was compared between groups for landing and push-off with a mixed model ANOVA. Compared to the No-fear group, the Fear group presented significant decreased power in the ankle (P < .001) but increased power in the knee (P < .001) in involved limb during both phases. A 3-way interaction was found between group, side, and phase for frontal plane hip power (P < .001). Our findings indicate that those who are afraid of reinjury demonstrate higher interlimb differences compared to those who are not. They also compensate for ankle deficits with greater knee and hip power.
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