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- Armannsdottir, A., et al.
(author)
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Frontal plane pelvis and hip kinematics of transfemoral amputee gait. Effect of a prosthetic foot with active ankle dorsiflexion and individualized training - a case study
- 2018
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In: Disability and Rehabilitation-Assistive Technology. - : Informa UK Limited. - 1748-3107 .- 1748-3115. ; 13:4, s. 388-393
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Journal article (peer-reviewed)abstract
- Following a transfemoral amputation (TFA), numerous changes in movement patterns during gait can occur. Frontal plane hip and pelvis compensatory strategies are recognized among individuals with a TFA, some thought to aid in safe foot clearance during the swing phase of gait. The aim of this case study was to evaluate the effect of an active ankle dorsiflexion provided by a microprocessor-controlled prosthetic foot, as well as the effect of individualized training on these parameters. In this case study, a 42-year-old male underwent 3D gait analysis. Data were captured for two conditions; with a microprocessor-controlled prosthetic foot with active/inactive ankle dorsiflexion, during two sessions; before and after 6 weeks of individualized training. The main outcomes analyzed were frontal plane pelvis and hip kinematics. Prior to training, pelvic lift decreased slightly, coupled with an increase in hip abduction, during gait with the active ankle dorsiflexion of a prosthetic foot, compared to inactive dorsiflexion. After the training period, the pelvic lift was further decreased and an increase in hip adduction was concurrently seen. The results of this case study indicate a positive effect of the active dorsiflexion of the prosthetic foot but highlight the need for specific training after prescription of a microprocessor prosthetic foot.
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- Briem, Valdimar, et al.
(author)
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Young drivers´ accident patterns
- 2000
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In: Human Factors in Telecommunications - Implications for the Aged and Disabled. - 9042301198
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Book chapter (other academic/artistic)abstract
- The present study is concerned with the impact of psychological factors, particularly character traits and attitudes, on the traffic accident patterns of young drivers. 101 drivers completed a questionnaire consisting of 206 questions and statements. Factor analysis was used to identify and eliminate non-significant test items, leaving 70 statements defining 14 distinct traits. Age and sex were shown to affect the frequency of traffic accidents and offences, the youngest male drivers representing the highest risk group. The relation of psychological traits to other variables is described as referring to seven groups of drivers, four "safe" and three "unsafe", each defined by a combination of distinct characteristics. While, superficially, a driver's age and sex may appear to be the chief determinants of the risk of accidents and offences, this risk is, firstly, determined by the driver's traffic exposure and experience, and secondly, by "chronic" and "tonic" traits, some of which are linked to age and sex.
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- 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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- 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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- Sigurdsson, H. B., et al.
(author)
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Kinematics observed during ACL injury are associated with large early peak knee abduction moments during a change of direction task in healthy adolescents
- 2021
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In: Journal of Orthopaedic Research. - : Wiley. - 0736-0266 .- 1554-527X. ; 39:10, s. 2281-2290
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Journal article (peer-reviewed)abstract
- Cluster analysis of knee abduction moment waveforms may be useful to examine biomechanical data. The aim of this study was to analyze if the knee abduction moment waveform of early peaks, consistent with anterior cruciate ligament injury mechanisms, was associated with foot-trunk distance, knee kinematics, and heel strike landing posture, all of which have been observed during anterior cruciate ligament injuries. One hundred and seventy-seven adolescent athletes performed cutting maneuvers, marker-based motion capture collected kinetic and marker data and an 8-segment musculoskeletal model was constructed. Knee abduction moment waveforms were clustered as either a large early peak, or not a large early peak using a two-step process with Euclidean distances and the Ward-d2 cluster method. Mediolateral distance between foot and trunk was associated with the large early peak waveform with an odds ratio (95% confidence interval) of 3.4 (2.7-4.4). Knee flexion angle at initial contact and knee flexion excursion had odds ratios of 1.9 (1.6-2.4) and 1.6 (1.3-2.0). Knee abduction excursions had an odds ratio of 1.8 (1.1-2.4) and 1.8 (1.4-2.4), respectively. Heel strike landings and anteroposterior distance between foot and trunk were not associated with the large early peak waveform with odds ratios of 1.2 (0.9-1.7) and 1.1 (0.8-1.3), respectively. The knee abduction moment waveform is associated with several kinematic variables observed during ACL injury. The results support intervention programs that can modify these kinematics and thus reduce early stance phase knee abduction moments.
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