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Bjerkefors, Anna
Publications (10 of 25) Show all publications
Edwards, J., Bjerkefors, A., Rosén, J. S. & Tarassova, O. (2019). Paracanoe. In: Don McKenzie, Bo Berglund (Ed.), Canoeing: (pp. 106-115). Hoboken, NJ: Wiley-Blackwell
Open this publication in new window or tab >>Paracanoe
2019 (English)In: Canoeing / [ed] Don McKenzie, Bo Berglund, Hoboken, NJ: Wiley-Blackwell, 2019, p. 106-115Chapter in book (Other academic)
Place, publisher, year, edition, pages
Hoboken, NJ: Wiley-Blackwell, 2019
Series
Handbook of sports medicine and science
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5642 (URN)9781119097204 (ISBN)
Available from: 2019-03-18 Created: 2019-03-18 Last updated: 2019-09-25Bibliographically approved
Rosén, J. S., Arndt, A., Goosey-Tolfrey, V. L., Mason, B. S., Hutchinson, M. J., Tarassova, O. & Bjerkefors, A. (2019). The impact of impairment on kinematic and kinetic variables in Va'a paddling: Towards a sport-specific evidence-based classification system for Para Va'a.. Journal of Sports Sciences, 37(17), 1942-1950
Open this publication in new window or tab >>The impact of impairment on kinematic and kinetic variables in Va'a paddling: Towards a sport-specific evidence-based classification system for Para Va'a.
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2019 (English)In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 37, no 17, p. 1942-1950Article in journal (Refereed) Published
Abstract [en]

Para Va'a is a new Paralympic sport in which athletes with trunk and/or leg impairment compete over 200 m. The purpose of this study was to examine the impact of impairment on kinematic and kinetic variables during Va'a ergometer paddling. Ten able-bodied and 44 Para Va'a athletes with impairments affecting: trunk and legs (TL), legs bilaterally (BL) or leg unilaterally (UL) participated. Differences in stroke frequency, mean paddling force, and joint angles and correlation of the joint angles with paddling force were examined. Able-bodied demonstrated significantly greater paddling force as well as knee and ankle flexion ranges of movement (ROM) on the top hand paddling side compared to TL, BL and UL. Able-bodied, BL and UL demonstrated greater paddling force and trunk flexion compared to TL, and UL demonstrated larger bottom hand paddling side knee and ankle flexion ROM compared to BL. Significant positive correlations were observed for both male and female athletes between paddling force and all trunk flexion angles and ROM in the trunk and pelvis rotation and bottom hand paddling side hip, knee and ankle flexion. The results of this study are important for creating an evidence-based classification system for Para Va'a.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
Outrigger, disability, paddling force, paralympics
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5717 (URN)10.1080/02640414.2019.1606763 (DOI)000470359400001 ()31006343 (PubMedID)
Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-08-13
Bjerkefors, A., Rosén, J. S., Tarassova, O. & Arndt, A. (2019). Three-Dimensional Kinematics and Power Output in Elite Para-Kayakers and Elite Able-Bodied Flat-Water Kayakers.. Journal of Applied Biomechanics, 93-100
Open this publication in new window or tab >>Three-Dimensional Kinematics and Power Output in Elite Para-Kayakers and Elite Able-Bodied Flat-Water Kayakers.
2019 (English)In: Journal of Applied Biomechanics, ISSN 1065-8483, E-ISSN 1543-2688, p. 93-100Article in journal (Refereed) Published
Abstract [en]

Trunk, pelvis and leg movement are important for performance in sprint kayaking. Para-kayaking is a new Paralympic sport in which athletes with trunk and/or leg impairment compete in three classification groups. The purpose of this study was to identify how physical impairments impact on performance by examining: differences in three-dimensional joint range of motion (RoM) between 10 (4 females, 6 males) elite able-bodied kayakers and 41 (13 females, 28 males) elite para-kayakersfrom the three classification groups, and which joint angles were correlated with power output during high intensity kayak ergometer paddling. There were significant differences in RoM between the able-bodied kayakers and the three para-kayak groups for the shoulders (flexion, rotation: able-bodied kayakers<para-kayakers), trunk and pelvis (rotation: able-bodied kayakers>para-kayakers) and legs (hip, knee, ankle flexion: able-bodied kayakers>para-kayakers) during paddling. Furthermore, athletes with greater impairment exhibited lower trunk and leg RoM compared to those with less impairment. Significant positive correlations were observed for both males and females between power output and peak shoulder and trunk flexion, trunk and pelvis rotation RoM and hip, knee and ankle flexion RoM. This information is important for understanding how key kinematic and kinetic variables for para-kayaking performance vary between athletes from different classification groups.

Place, publisher, year, edition, pages
Human Kinetics, 2019
Keywords
3D analysis, Paralympics, canoe, disability, ergometer, kinetics
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5432 (URN)10.1123/jab.2017-0102 (DOI)000461017800001 ()30300050 (PubMedID)
Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2019-03-29Bibliographically approved
Bjerkefors, A. (2018). Positive Effects of Kayak and Kayak Ergometer Training by people with Paraplegia. In: : . Paper presented at The Second World Paracanoe Conference, October 5-7 2018, Stockholm.
Open this publication in new window or tab >>Positive Effects of Kayak and Kayak Ergometer Training by people with Paraplegia
2018 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

Background Spinal cord injury (SCI) results in a complete or partial loss of motor and/or sensory function below the injury level. An SCI causes extensive functional impairment compelling many persons to wheelchair usage. Maintaining an adequate strength and control of trunk and shoulder muscles becomes essential, as the majority of every day tasks will be performed in a sitting position. Moreover, physical exercise is crucial to avoid risks connected with a sedentary life-style. Therefore, it becomes important to find suitable, effective, and attractive physical activities to retain and even improve motor functions achieved during rehabilitation. Ideally, such a training activity should be versatile and have the potential to improve several capacities beneficial to everyday life and thereby increase the independence of persons with SCI. Kayak paddling appears to fulfil several of the criteria for such an activity.

Objectives The overall aims were to see if, and to what extent, a period of training on a modified kayak ergometer could influence functional performance as well as specific qualities, such as, shoulder muscle strength and sitting balance control in a group of post-rehabilitated persons with thoracic SCI.

Methods Ten adult post-rehabilitated persons with thoracic SCI performed 30 sessions of kayak ergometer training for a 10-week period, with progressively increased intensity and balance demand in the medio-lateral direction. Pre- and post-training measurements included performance in functional wheelchair tests, maximal voluntary shoulder muscle strength, and trunk stability in response to support-surface translations.

Results There were significant improvements with training in functional performance, shoulder muscle strength, and the ability to maintain an upright sitting posture in response to balance perturbations in the group of persons with SCI.

Conclusions The improvements in test-performance observed with the kayak ergometer training in the persons with SCI should enhance their capacity to master similar challenges in everyday life, which, in turn, might lead to a greater independence.

Keywords
parasport, rehabilitation, spinal cord injury, canoe, kayak, ergometer
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5540 (URN)
Conference
The Second World Paracanoe Conference, October 5-7 2018, Stockholm
Available from: 2019-01-14 Created: 2019-01-14 Last updated: 2019-01-15Bibliographically approved
Squair, J. W., Bjerkefors, A., Inglis, J. T., Lam, T. & Carpenter, M. G. (2016). Cortical and vestibular stimulation reveal preserved descending motor pathways in individuals with motor-complete spinal cord injury.. Journal of Rehabilitation Medicine, 48(7), 589-596
Open this publication in new window or tab >>Cortical and vestibular stimulation reveal preserved descending motor pathways in individuals with motor-complete spinal cord injury.
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2016 (English)In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 48, no 7, p. 589-596Article in journal (Refereed) Published
Abstract [en]

OBJECTIVE: To use a combination of electrophysiological techniques to determine the extent of preserved muscle activity below the clinically-defined level of motor-complete spinal cord injury.

METHODS: Transcranial magnetic stimulation and vestibular-evoked myogenic potentials were used to investigate whether there was any preserved muscle activity in trunk, hip and leg muscles of 16 individuals with motor-complete spinal cord injury (C4-T12) and 16 able-bodied matched controls.

RESULTS: Most individuals (14/16) with motor-complete spinal cord injury were found to have transcranial magnetic stimulation evoked, and/or voluntary evoked muscle activity in muscles innervated below the clinically classified lesion level. In most cases voluntary muscle activation was accompanied by a present transcranial magnetic stimulation response. Furthermore, motor-evoked potentials to transcranial magnetic stimulation could be observed in muscles that could not be voluntarily activated. Vestibular-evoked myogenic potentials responses were also observed in a small number of subjects, indicating the potential preservation of other descending pathways.

CONCLUSION: These results highlight the importance of using multiple electrophysiological techniques to assist in determining the potential preservation of muscle activity below the clinically-defined level of injury in individuals with a motor-complete spinal cord injury. These techniques may provide clinicians with more accurate information about the state of various motor pathways, and could offer a method to more accurately target rehabilitation.

National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-4480 (URN)10.2340/16501977-2101 (DOI)000378941400005 ()27292455 (PubMedID)
Available from: 2016-06-22 Created: 2016-06-22 Last updated: 2017-11-28Bibliographically approved
Bjerkefors, A., Squair, J. W., Chua, R., Lam, T., Chen, Z. & Carpenter, M. G. (2015). Assessment of abdominal muscle function in individuals with motor-complete spinal cord injury above T6 in response to transcranial magnetic stimulation.. Journal of Rehabilitation Medicine, 47(2), 138-146
Open this publication in new window or tab >>Assessment of abdominal muscle function in individuals with motor-complete spinal cord injury above T6 in response to transcranial magnetic stimulation.
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2015 (English)In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 47, no 2, p. 138-146Article in journal (Refereed) Published
Abstract [en]

Objective: To use transcranial magnetic stimulation and electromyography to assess the potential for preserved function in the abdominal muscles in individuals classified with motor-complete spinal cord injury above T6. Subjects: Five individuals with spinal cord injury (C5-T3) and 5 able-bodied individuals. Methods: Transcranial magnetic stimulation was delivered over the abdominal region of primary motor cortex during resting and sub-maximal (or attempted) contractions. Surface electromyography was used to record motor-evoked potentials as well as maximal voluntary (or attempted) contractions in the abdominal muscles and the diaphragm. Results: Responses to transcranial magnetic stimulation in the abdominal muscles occurred in all spinal cord injury subjects. Latencies of muscle response onsets were similar in both groups; however, peak-to-peak amplitudes were smaller in the spinal cord injury group. During maximal voluntary (or attempted) contractions all spinal cord injury subjects were able to elicit electromyography activity above resting levels in more than one abdominal muscle across tasks. Conclusion: Individuals with motor-complete spinal cord injury above T6 were able to activate abdominal muscles in response to transcranial magnetic stimulation and during maximal voluntary (or attempted) contractions. The activation was induced directly through corticospinal pathways, and not indirectly by stretch reflex activations of the diaphragm. Transcranial magnetic stimulation and electromyography measurements provide a useful method to assess motor preservation of abdominal muscles in persons with spinal cord injury.

National Category
Neurology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-3639 (URN)10.2340/16501977-1901 (DOI)25502735 (PubMedID)
Available from: 2015-01-07 Created: 2015-01-07 Last updated: 2017-12-05Bibliographically approved
Bjerkefors, A., Squair, J. W., Malik, R., Lam, T., Chen, Z. & Carpenter, M. G. (2015). Diagnostic accuracy of common clinical tests for assessing abdominal muscle function after motor-complete spinal cord injury above T6.. Spinal Cord, 53, 114-119
Open this publication in new window or tab >>Diagnostic accuracy of common clinical tests for assessing abdominal muscle function after motor-complete spinal cord injury above T6.
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2015 (English)In: Spinal Cord, ISSN 1362-4393, E-ISSN 1476-5624, Vol. 53, p. 114-119Article in journal (Refereed) Published
Abstract [en]

Study design:Diagnostic study.Objectives:The objective of this study was to compare patterns of electromyography (EMG) recordings of abdominal muscle function in persons with motor-complete spinal cord injury (SCI) above T6 and in able-bodied controls, and to determine whether manual examination or ultrasound measures of muscle activation can be accurate alternatives to EMG.Setting:Research center focused on SCI and University laboratory, Vancouver, Canada.Methods:Thirteen people with SCI (11 with American Spinal Injury Association Impairment Scale (AIS) A and 2 AIS B; C4-T5), and 13 matched able-bodied participants volunteered for the study. Participants completed trunk tasks during manual examination of the abdominal muscles and then performed maximal voluntary isometric contractions, while EMG activity and muscle thickness changes were recorded. The frequency of muscle responses detected by manual examination and ultrasound were compared with detection by EMG (sensitivity and specificity).Results:All individuals with SCI were able to elicit EMG activity above resting levels in at least one abdominal muscle during one task. In general, the activation pattern was task specific, confirming voluntary control of the muscles. Ultrasound, when compared with EMG, showed low sensitivity but was highly specific in its ability to detect preserved abdominal muscle function in persons with SCI. Conversely, manual examination was more sensitive than ultrasound but showed lower specificity.Conclusion:The results from this study confirm preserved voluntary abdominal muscle function in individuals classified with motor-complete SCI above T6 and highlight the need for further research in developing more accurate clinical measures to diagnose the level of trunk muscle preservation in individuals with SCI.Spinal Cord advance online publication, 25 November 2014; doi:10.1038/sc.2014.202.

National Category
Neurology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-3574 (URN)10.1038/sc.2014.202 (DOI)25420495 (PubMedID)
Available from: 2014-11-26 Created: 2014-11-26 Last updated: 2017-12-05Bibliographically approved
Bjerkefors, A., Squair, J. W., Malik, R., Lam, T., Chen, Z. & Carpenter, M. G. (2015). Response to 'Diagnostic accuracy of common clinical tests for assessing abdominal muscle function after motor-complete spinal cord injury above T6'. [Letter to the editor]. Spinal Cord, 53(12), 892-892
Open this publication in new window or tab >>Response to 'Diagnostic accuracy of common clinical tests for assessing abdominal muscle function after motor-complete spinal cord injury above T6'.
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2015 (English)In: Spinal Cord, ISSN 1362-4393, E-ISSN 1476-5624, Vol. 53, no 12, p. 892-892Article in journal, Letter (Other academic) Published
National Category
Neurology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-4133 (URN)10.1038/sc.2015.115 (DOI)000366488200014 ()26169168 (PubMedID)
Available from: 2015-09-14 Created: 2015-09-14 Last updated: 2017-12-04Bibliographically approved
Bjerkefors, A., Squair, J., Chen, Z., Lam, T. & Carpenter, M. (2014). Postural control in individuals with spinal cord injury: Training, functional performance, and mechanisms. In: : . Paper presented at ISPGR World Congress 2014 (International Society of Postural and Gait research), Vancouver, Canada, June 29 - July 3 2014.
Open this publication in new window or tab >>Postural control in individuals with spinal cord injury: Training, functional performance, and mechanisms
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2014 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

BACKGROUND AND AIM: Postural control in sitting is essential for people with spinal cord injury (SCI). Studies indicate that impaired postural control is related to decreased propulsion efficiency, respiratory dysfunction and development of pressure sores. Despite this, there is limited knowledge on the best methods to rehabilitate postural control in people with SCI and if and by what mechanism persons with high-thoracic SCI may improve their postural control. Thus, our aims were to 1) determine the efficacy of targeted rehabilitation towards postural control in people with SCI, and 2) investigate the neural mechanisms behind any observed improvements.

 

METHODS: Persons with SCI completed 30 sessions over 10 weeks of a) seated double poling ergometer (SDP) training (n=13) or b) kayak ergometer (KE) training (n=10). Before and after functional tests were performed and included: sit-and-reach tests, propelling 15m on a level surface and propelling 50m up a 3º incline. Additionally, subjects sat in their wheelchair while support-surface translations were presented (KE) or performed isometric maximal voluntary contractions in a dynamometer during trunk flexion and extension (SDP). To investigate neural mechanisms of postural control improvement, electromyographic (EMG) responses in the ventral postural muscles to maximal voluntary contractions and transcranial magnetic stimulation (TMS) were assessed in 5 individuals with motor complete SCI above T6.

 

RESULTS: Postural stability was improved after KE and SDP training demonstrated by smaller rotational and linear displacements of the trunk during support surface translations (KE) and improved postural muscle strength (SDP). There were also significant improvements in propelling tasks and in the sit-and-reach tasks, both in the sagittal plane (SDP) as well as in lateral directions (KE). All persons with motor complete SCI above T6 (n=5) were able to elicit task specific EMG activity in the ventral postural muscles during maximal voluntary contractions despite their clinical classification. Motor evoked potentials were also recorded in each individual´s ventral postural muscles in response to TMS, confirming corticospinal pathway preservation.

 

CONCLUSIONS: Postural control, upright sitting, and functional performance in daily life activities can be improved in people with high-thoracic SCI during regular exercising, such as kayaking and seated double poling ergometer training. The neural mechanism behind the improvement is in part due to partial preservation of the corticospinal pathways to the postural muscles as confirmed by the use EMG and TMS.

 

Keywords
postural control, balance, spinal cord injury, kayak, training
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-3654 (URN)
Conference
ISPGR World Congress 2014 (International Society of Postural and Gait research), Vancouver, Canada, June 29 - July 3 2014
Funder
Swedish National Centre for Research in Sports
Available from: 2015-01-09 Created: 2015-01-09 Last updated: 2017-10-02Bibliographically approved
Bjerkefors, M.-E. & Bjerkefors, A. (2013). Kajak & skridskohandbok: för dig med funktionsnedsättning. Stockholm: RG Aktiv Rehabilitering
Open this publication in new window or tab >>Kajak & skridskohandbok: för dig med funktionsnedsättning
2013 (Swedish)Book (Other (popular science, discussion, etc.))
Abstract [sv]

Med kajak- och skridskohandboken vill vi dela med oss av våra erfarenheter. Boken kan ses både som en inspirationskälla för nya aktiva och som en handbok för ledare och föreningar som vill starta friluftsverksamhet för personer med funktionsnedsättning.

Place, publisher, year, edition, pages
Stockholm: RG Aktiv Rehabilitering, 2013. p. 151
National Category
Social Sciences
Research subject
Social Sciences/Humanities
Identifiers
urn:nbn:se:gih:diva-2801 (URN)9789163730870 (ISBN)
Available from: 2013-05-23 Created: 2013-05-23 Last updated: 2017-10-02Bibliographically approved
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