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Heegaard M, Tøndevold N, Dahl B, Andersen TB, Gehrchen M, Ohrt-Nissen S. The effect of Providence night-time bracing on the sagittal profile in adolescent idiopathic scoliosis. Eur Spine J 2024; 33:1657-1664. [PMID: 38430401 DOI: 10.1007/s00586-024-08186-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/18/2023] [Accepted: 02/04/2024] [Indexed: 03/03/2024]
Abstract
PURPOSE Adolescent idiopathic scoliosis (AIS) is characterized by coronal scoliosis and often a sagittal hypokyphosis. The effect of bracing on the sagittal profile is not well understood. The aim of this study is to assess the effect of night-time bracing on the sagittal profile in patients with AIS. METHODS We retrospectively included AIS patients with a main curve of 25-45° treated with a night-time brace in our institution between 2005 and 2018. Patients with estimated growth potential based on either Risser stage, hand X-rays, or menarchal status were included. Coronal and sagittal radiographic parameters were recorded at both brace- initiation and -termination. Patients were followed until surgery or one year after brace termination. Results were compared to a published cohort of full-time braced patients. RESULTS One hundred forty-six patients were included. Maximum thoracic kyphosis (TK) increased 2.5° (± 9.7) (p = 0.003), corresponding to a 3.5-fold relative risk increase post bracing in TK compared to a full-time brace cohort. Twenty-seven percent (n = 36) of the patients were hypokyphotic (T4/T12 < 20°) at brace initiation compared with 19% (n = 26) at brace termination (p = 0.134). All other sagittal parameters remained the same at follow-up. We found no association between progression in the coronal plane and change in sagittal parameters. CONCLUSION This is the first study to indicate that night-time bracing of AIS does not induce hypokyphosis. We found a small increase in TK, with a substantially lower risk of developing flat back deformity compared to full-time bracing. The coronal curve progression was not coupled to a change in TK.
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Affiliation(s)
- Martin Heegaard
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark.
| | - Niklas Tøndevold
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Benny Dahl
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Thomas B Andersen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Martin Gehrchen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Søren Ohrt-Nissen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
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Heegaard M, Tøndevold N, Dahl B, Andersen TB, Gehrchen M, Ohrt-Nissen S. The influence of night-time bracing on curve progression is not affected by curve magnitude in adolescent idiopathic scoliosis: a study of 299 patients. Acta Orthop 2024; 95:108-113. [PMID: 38347730 PMCID: PMC10863495 DOI: 10.2340/17453674.2024.39965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/06/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND AND PURPOSE The efficacy of bracing larger curves in adolescent idiopathic scoliosis (AIS) patients is uncertain. We aimed to assess the influence of night-time bracing in AIS patients with main curves exceeding 40° Cobb angle at brace initiation. METHODS We reviewed AIS patients treated with nighttime braces between 2005 and 2018. Patients with curves ≥ 25° and estimated growth potential were included. Patients were monitored with radiographs from brace initiation until brace weaning at skeletal maturity. Patients were grouped based on curve magnitude at initial evaluation: a control group (25-39°) and a large-curves group (≥ 40°). Progression was defined as > 5° increase. RESULTS We included 299 patients (control group, n = 125; large-curves group, n = 174). In the control group, 65 (52%) patients progressed compared with 101 (58%) in the large-curves group (P = 0.3). The lower-end vertebra (LEV) shifted distally post-bracing in 41 (23%) patients in the largecurves group. Patients with progressive large curves were younger (age 13.2 [SD 1.5] vs. 13.9 [SD 1.1], P = 0.009) and more premenarchal (n = 36 [42%] vs. n = 6 [9%], P < 0.001) compared with non-progressive large curves. CONCLUSION Progression risk in patients with curves exceeding 40° treated with night-time bracing is similar to smaller curves. The LEV moved distally in almost one-fourth of the larger curves, possibly affecting fusion levels in cases of surgery.
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Affiliation(s)
- Martin Heegaard
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
| | - Niklas Tøndevold
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Benny Dahl
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Thomas B Andersen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Martin Gehrchen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Søren Ohrt-Nissen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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Heegaard M, Tøndevold N, Dahl B, Andersen TB, Gehrchen M, Ohrt-Nissen S. Does Risser stage accurately predict the risk of curve progression in patients with adolescent idiopathic scoliosis treated with night-time bracing? Eur Spine J 2023; 32:3077-3083. [PMID: 37314578 DOI: 10.1007/s00586-023-07808-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 04/03/2023] [Accepted: 06/01/2023] [Indexed: 06/15/2023]
Abstract
PURPOSE Risser stage is widely used as a marker for skeletal maturity (SM) and thereby an indirect measure for the risk of progression of adolescent idiopathic scoliosis (AIS). The Scoliosis Research Society recommends bracing for Risser stages 0-2 as Risser stage 3 or above is considered low risk. Very few studies have assessed the risk of progression during bracing in Risser stages 3-4. The objective of the current study is to determine if Risser stages 3-4 provide a meaningful cutoff in terms of progression risk in patients with AIS treated with night-time bracing. METHODS AIS patients treated with night-time brace from 2005 to 2018 with a Cobb angle between 25 and 40 degrees and Risser stages 0-4 were retrospectively included. Curve progression (> 5 degrees increase) was monitored until surgery or SM. Skeletal maturity was defined as either 2 years postmenarchal, no height development or closed ulnar epiphyseal plates on radiographs. RESULTS One hundred and thirty-five patients were included (Risser stages 0-2: n = 86 and 3-4: n = 49). Overall, radiographic curve progression occurred in 52% while progression beyond 45 degrees was seen in 35%. The progression rate in the Risser 0-2 group was 60% and 37% in the Risser 3-4 group (p = 0.012). In multivariate logistic regression analysis, adjusted for Risser stages and age, only premenarchal status showed a statistically significant association with progression (OR: 2.68, 95%CI 1.08-6.67). CONCLUSION Risser stage does not provide a clinically meaningful differentiation of progression risk in AIS patients treated with a night-time brace. Risk assessment should include other more reliable measures of skeletal growth potential.
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Affiliation(s)
- Martin Heegaard
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark.
| | - Niklas Tøndevold
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Benny Dahl
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Thomas B Andersen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Martin Gehrchen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
| | - Søren Ohrt-Nissen
- Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 6, 2100, Copenhagen, Denmark
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Naume MM, Møller MH, Høi‐Hansen CE, Born AP, Brekke G, Andersen TB, Dirks J, Ørngreen MC. Early postoperative complications were common in non-ambulant paediatric patients with neuromuscular scoliosis. Acta Paediatr 2022; 111:593-594. [PMID: 34767273 DOI: 10.1111/apa.16183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/05/2021] [Accepted: 11/10/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Marie Mostue Naume
- Department of Neurology Copenhagen Neuromuscular Centre Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Morten H. Møller
- Department of Intensive Care Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Christina E. Høi‐Hansen
- Department of Paediatrics and Adolescent Medicine Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Alfred P. Born
- Department of Paediatrics and Adolescent Medicine Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Ghita Brekke
- Department of Paediatrics and Adolescent Medicine Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Thomas B. Andersen
- Department of Orthopaedic Surgery Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Jesper Dirks
- Department of Anesthesiology Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Mette Cathrine Ørngreen
- Department of Neurology Copenhagen Neuromuscular Centre Copenhagen University HospitalRigshospitalet Copenhagen Denmark
- Department of Paediatrics and Adolescent Medicine Copenhagen University HospitalRigshospitalet Copenhagen Denmark
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Wong C, Andersen TB. Evaluation of Brace Treatment Using the Soft Brace Spinaposture: A Four-Years Follow-Up. J Clin Med 2022; 11:jcm11010264. [PMID: 35012005 PMCID: PMC8745903 DOI: 10.3390/jcm11010264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/29/2021] [Accepted: 12/31/2021] [Indexed: 02/05/2023] Open
Abstract
The braces of today are constructed to correct the frontal plane deformity of idiopathic adolescent scoliosis (AIS). The Spinaposture brace© (Spinaposture Aps, Copenhagen, Denmark) is a soft-fabric brace for AIS and is designed to enhance rotational axial stability by inducing a sagittal plane kyphotic correction. This prospective observational study evaluated the brace in fifteen patients with AIS. The initial average CA was 16.8° (SD: 2.8). They were followed prospectively every 3 to 6 months during their brace usage until skeletal maturity of 25 months and at long-term follow-up of 44 months. In- and out-of-brace radiographs were performed in six subjects at inclusion. This resulted in an immediate in-brace correction of 25.3 percent in CA (14.3°→10.8°) and induced a kyphotic effect of 14.9 percent (40.8°→47.9°). The average in-brace improvement at first follow-up was 4.5° in CA, and the CA at skeletal maturity was 11° (SD: 7.4°) and long-term 12.0° (SD: 6.8°). In conclusion, the Spinaposture brace© had an immediate in-brace deformity correction and a thoracic kyphotic effect. At skeletal maturity, the deformities improved more than expected when compared to that of the natural history/observation and similar to that of other soft braces. No long-term deformity progression was seen. To substantiate these findings, stronger designed studies with additional subjects are needed.
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Affiliation(s)
- Christian Wong
- Department of Orthopedics, Hvidovre Hospital, Kettegaards Alle 30, 2650 Hvidovre, Denmark
- Correspondence: ; Tel.: +45-38-62-66-69
| | - Thomas B. Andersen
- Department of Orthopedics, National University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark;
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Vigh-Larsen JF, Haverinen MT, Panduro J, Ermidis G, Andersen TB, Overgaard K, Krustrup P, Parkkari J, Avela J, Kyröläinen H, Mohr M. On-Ice and Off-Ice Fitness Profiles of Elite and U20 Male Ice Hockey Players of Two Different National Standards. J Strength Cond Res 2021; 34:3369-3376. [PMID: 33009345 DOI: 10.1519/jsc.0000000000003836] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vigh-Larsen, JF, Haverinen, MT, Panduro, J, Ermidis, G, Andersen, TB, Overgaard, K, Krustrup, P, Parkkari, J, Avela, J, Kyröläinen, H, and Mohr, M. On-ice and off-ice fitness profiles of elite and U20 male ice hockey players of two different national standards. J Strength Cond Res 34(12): 3369-3376, 2020-Differences in body composition and performance were investigated between elite and U20 male ice hockey players of 2 different national standards. One hundred seventy-nine players were recruited from the highest Finnish (n = 82) and Danish (n = 61) national level, as well as from 1 U20 team from Finland (n = 19) and Denmark (n = 17). Body composition and countermovement jump performance (CMJ) were measured off-ice in addition to on-ice assessments of agility, 10- and 30-m sprint performance, and endurance capacity (the maximal Yo-Yo Intermittent Recovery Level 1 Ice Hockey Test, Yo-Yo IR1-IHmax). Large differences in on-ice performances were demonstrated between Finnish and Danish elite players for agility, 10- and 30-m sprint performance (2-3%, P ≤ 0.05), and Yo-Yo IR1-IHmax performance (15%, P ≤ 0.05). By contrast, no differences (P > 0.05) were present between elite players for CMJ ability or body composition. However, elite players possessed more body and muscle mass than U20 players. Finally, the Finnish U20 cohort had a similar performance level as the Danish elite players and superior 10-m sprint performance, whereas the Danish U20 level was inferior to the other groups in every performance assessment (P ≤ 0.05). In conclusion, on-ice speed and endurance differ markedly between elite players of 2 different national standards with no distinction in body composition or CMJ ability. Moreover, the most consistent difference between U20 and senior elite players was related to body and muscle mass. These results highlight the usefulness of on-ice assessments and suggest the importance of on-ice high-intensity training in elite players in addition to training targeted the development of lean body mass in youth prospects.
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Affiliation(s)
- Jeppe F Vigh-Larsen
- Research Unit for Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Marko T Haverinen
- Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Varala Sports Institute, Tampere, Finland
| | - Jeppe Panduro
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Georgios Ermidis
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.,Department of Movement Sciences and Wellness, "Parthenope" University of Naples, Naples, Italy
| | - Thomas B Andersen
- Research Unit for Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Kristian Overgaard
- Research Unit for Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Peter Krustrup
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.,Shanghai University of Sport (SUS), Shanghai, China.,Sport and Health Sciences, University of Exeter, Exeter, United Kingdom
| | - Jari Parkkari
- Tampere Research Center of Sports Medicine, UKK Institute, Tampere, Finland
| | - Janne Avela
- Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland; and
| | - Heikki Kyröläinen
- Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland; and
| | - Magni Mohr
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.,Center of Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands
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Vigh-Larsen JF, Ermidis G, Rago V, Randers MB, Fransson D, Nielsen JL, Gliemann L, Piil JF, Morris NB, DE Paoli FV, Overgaard K, Andersen TB, Nybo L, Krustrup P, Mohr M. Muscle Metabolism and Fatigue during Simulated Ice Hockey Match-Play in Elite Players. Med Sci Sports Exerc 2021; 52:2162-2171. [PMID: 32496739 DOI: 10.1249/mss.0000000000002370] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The present study investigated muscle metabolism and fatigue during simulated elite male ice hockey match-play. METHODS Thirty U20 male national team players completed an experimental game comprising three periods of 8 × 1-min shifts separated by 2-min recovery intervals. Two vastus lateralis biopsies were obtained either during the game (n = 7) or pregame and postgame (n = 6). Venous blood samples were drawn pregame and at the end of the first and last periods (n = 14). Activity pattern and physiological responses were continuously monitored using local positioning system and heart rate recordings. Further, repeated-sprint ability was tested pregame and after each period. RESULTS Total distance covered was 5980 ± 199 m with almost half the distance covered at high skating speeds (>17 km·h). Average and peak on-ice heart rate was 84% ± 2% and 97% ± 2% of maximum heart rate, respectively. Muscle lactate increased (P ≤ 0.05) more than fivefold and threefold, whereas muscle pH decreased (P ≤ 0.05) from 7.31 ± 0.04 pregame to 6.99 ± 0.07 and 7.13 ± 0.11 during the first and last periods, respectively. Muscle glycogen decreased by 53% postgame (P ≤ 0.05) with ~65% of fast- and slow-twitch fibers depleted of glycogen. Blood lactate increased sixfold (P ≤ 0.05), whereas plasma free fatty acid levels increased 1.5-fold and threefold (P ≤ 0.05) after the first and last periods. Repeated-sprint ability was impaired (~3%; P ≤ 0.05) postgame concomitant with a ~10% decrease in the number of accelerations and decelerations during the second and last periods (P ≤ 0.05). CONCLUSIONS Our findings demonstrate that a simulated ice hockey match-play scenario encompasses a high on-ice heart rate response and glycolytic loading resulting in a marked degradation of muscle glycogen, particularly in specific sub-groups of fibers. This may be of importance both for fatigue in the final stages of a game and for subsequent recovery.
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Affiliation(s)
- Jeppe F Vigh-Larsen
- Department of Public Health, Research Unit for Exercise Biology, Aarhus University, Aarhus, DENMARK
| | | | | | | | - Dan Fransson
- Center for Health and Performance, Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg, SWEDEN
| | - Jakob L Nielsen
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), Faculty of Health Sciences, University of Southern Denmark, Odense, DENMARK
| | - Lasse Gliemann
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, DENMARK
| | - Jacob F Piil
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, DENMARK
| | - Nathan B Morris
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, DENMARK
| | | | - Kristian Overgaard
- Department of Public Health, Research Unit for Exercise Biology, Aarhus University, Aarhus, DENMARK
| | - Thomas B Andersen
- Department of Public Health, Research Unit for Exercise Biology, Aarhus University, Aarhus, DENMARK
| | - Lars Nybo
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, DENMARK
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Vigh-Larsen JF, Haverinen MT, Knudsen CB, Daasbjerg A, Beck JH, Overgaard K, Mohr M, Andersen TB. The relationship between age and fitness profiles in elite male ice hockey players. J Sports Med Phys Fitness 2020; 61:512-518. [PMID: 32880136 DOI: 10.23736/s0022-4707.20.11313-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The present study investigated relationships between age, body composition and performance in elite male ice hockey players. METHODS 199 players performed off-ice tests (countermovement jump height (CMJ) and body composition) and on-ice tests (5-10-5 Pro Agility test, 30-m sprint test and the maximal Yo-Yo Intermittent Recovery Ice Hockey test (Yo-Yo IR1-IH<inf>MAX</inf>) for assessment of aerobic capacity. RESULTS No overall correlations between age and performance were present except small-moderate positive associations between age and body- and muscle mass (r=0.24-0.30, P≤0.05). The youngest age group (YOU; 18-21 years) were 4-9% lighter than all other age groups and possessed 7% less muscle mass compared to the oldest players (OLD; 30-33 years) (P≤0.05), whereas no differences were present in body fat percentage. OLD were 2-3% inferior to the second youngest (SEC; 22-25 years) and mid-age group (MID; 26-29 years) in sprint and agility performance in addition to a 6-10% lower CMJ height (P≤0.05). The younger age groups differed only by a 7 and 5% better CMJ performance in MID compared to YOU and SEC, respectively (P≤0.05). In contrast, no differences were found in distance covered on the Yo-Yo IR1-IH<inf>max</inf>. CONCLUSIONS Only small-moderate associations between age and body composition were present unlike for the remaining performance parameters. Nevertheless, a consistently lower high-intensity exercise performance was evident in the oldest- and a lower body weight in the youngest players, whereas aerobic capacity was similar. This suggests that capabilities related to size, strength and power are the most critical parameters differing between young and old ice hockey players.
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Affiliation(s)
- Jeppe F Vigh-Larsen
- Research Unit for Exercise Biology, Department of Public Health, University of Aarhus, Aarhus, Denmark -
| | - Marko T Haverinen
- Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Varala Sports Institute, Tampere, Finland
| | - Christian B Knudsen
- Research Unit for Exercise Biology, Department of Public Health, University of Aarhus, Aarhus, Denmark
| | - Aleksander Daasbjerg
- Research Unit for Exercise Biology, Department of Public Health, University of Aarhus, Aarhus, Denmark
| | - Jonas H Beck
- Research Unit for Exercise Biology, Department of Public Health, University of Aarhus, Aarhus, Denmark
| | - Kristian Overgaard
- Research Unit for Exercise Biology, Department of Public Health, University of Aarhus, Aarhus, Denmark
| | - Magni Mohr
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.,Center of Health Sciences, Faculty of Health Science, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - Thomas B Andersen
- Research Unit for Exercise Biology, Department of Public Health, University of Aarhus, Aarhus, Denmark
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Vigh-Larsen JF, Beck JH, Daasbjerg A, Knudsen CB, Kvorning T, Overgaard K, Andersen TB, Mohr M. Fitness Characteristics of Elite and Subelite Male Ice Hockey Players: A Cross-Sectional Study. J Strength Cond Res 2019; 33:2352-2360. [DOI: 10.1519/jsc.0000000000003285] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Vigh-Larsen JF, Ermidis G, Rago V, Randers MB, Fransson D, Hybholt LG, de Paoli FV, Overgaard K, Andersen TB, Nybo L, Krustrup P, Mohr M. Muscle, Blood and Performance Responses to Ice Hockey Match-play in Elite Male Players. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000563474.66038.6a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vigh-Larsen JF, Dalgas U, Andersen TB. Position-Specific Acceleration and Deceleration Profiles in Elite Youth and Senior Soccer Players. J Strength Cond Res 2018; 32:1114-1122. [PMID: 28699924 DOI: 10.1519/jsc.0000000000001918] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vigh-Larsen, JF, Dalgas, U, and Andersen, TB. Position-specific acceleration and deceleration profiles in elite youth and senior soccer players. J Strength Cond Res 32(4): 1114-1122, 2018-The purpose of the study was to characterize and compare the position-specific activity profiles of young and senior elite soccer players with special emphasis put on accelerations and decelerations. Eight professional senior matches were tracked using the ZXY tracking system and analyzed for the number of accelerations and decelerations and running distances within different speed zones. Likewise, 4 U19 and 5 U17 matches were analyzed for comparison between youth and senior players. In senior players, the total distance (TD) was 10,776 ± 107 m with 668 ± 28 and 143 ± 10 m being high-intensity running (HIR) and sprinting, respectively. Number of accelerations and decelerations were 81 ± 2 and 84 ± 3, respectively, with central defenders performing the lowest and wide players the highest number. Declines were found between first and second halves for accelerations and decelerations (11 ± 3%), HIR (6 ± 4%), and TD (5 ± 1%), whereas sprinting distance did not differ. U19 players performed a higher number of accelerations, decelerations, and TD compared with senior players. In conclusion, differences in the number and distribution of accelerations and decelerations appeared between player positions, which is of importance when monitoring training and match loads and when prescribing specific training exercises. Furthermore, youth players performed as much high-intensity activities as senior players, indicating that this is not a discriminating physiological parameter between these players.
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Affiliation(s)
- Jeppe F Vigh-Larsen
- Section for Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark
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Abstract
Knudsen, NS and Andersen, TB. Detection of spatiotemporal asymmetry in pro level soccer players. J Strength Cond Res 32(3): 798-804, 2018-Several papers have focused on change of direction (COD) asymmetry investigated through standardized tests, and used this information to provide some spatiotemporal insight during games. The aim of this study was to investigate asymmetry in the reachable areas of the players through actual position data from soccer games. Sixteen professional players from the Danish Superliga participated in this study, but 5 were excluded because of lack of participation throughout the investigated games. The reachable areas of the players were investigated at varying sprint velocities (1-7 m·s) and within varying time intervals (0.5-4 seconds). The analysis found 7 players having spatiotemporal asymmetries in their reachable areas (0.5-3%) and shift of center of reachable area (4-29 cm). Four players (LB, RB, DM, and CF) had spatiotemporal asymmetries that could be attributed to COD and thus physiological asymmetries, whereas 3 players (LCB, LW, and RW) had spatiotemporal asymmetries that might be caused by their position or by use of tactic. This type of asymmetry was named a tactical spatiotemporal asymmetry. Coaches with knowledge about spatiotemporal asymmetries can use these actively in their tactical approach using the players' asymmetries in synergy, using opponents' asymmetries or improving the existing postgame spatiotemporal analyzing tools.
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Affiliation(s)
- Nikolas S Knudsen
- Department of Public Health, Section of Sport Science, Aarhus University, Aarhus, Denmark
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Zebis MK, Thorborg K, Andersen LL, Møller M, Christensen KB, Clausen MB, Hölmich P, Wedderkopp N, Andersen TB, Krustrup P. Effects of a lighter, smaller football on acute match injuries in adolescent female football: a pilot cluster-randomized controlled trial. J Sports Med Phys Fitness 2018; 58:644-650. [PMID: 29719944 DOI: 10.23736/s0022-4707.17.07903-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The high injury incidence during match-play in female adolescent football is a major concern. In football, males and females play matches with the same football size. No studies have investigated the effect of football size on injury incidence in female adolescent football. Thus, the aim of the present study was to investigate the effects of introducing a lighter, smaller football on the injury pattern in female adolescent football. METHODS We conducted a pilot cluster randomized controlled trial including 26 football teams representing 346 adolescent female football players (age 15-18 years). The teams were randomized to a new lighter, smaller football (INT, N.=12 teams) or a traditional FIFA size 5 football (CON, N.=14 teams) during a full match-season. Acute time-loss injuries and football-exposure during match-play were reported weekly by text-message questions and verified subsequently by telephone interview. RESULTS In total, 46 acute time-loss injuries were registered (5 severe injuries), yielding an incidence rate of 15.2 injuries per 1000 hours of match-play (95% CI: 8.5-27.2) in INT and 18.6 injuries per 1000 hours of match-play (95% CI: 14.0-24.8) in CON. The estimated 22% greater injury incidence rate risk (IRR: 1.22 [95% CI: 0.64-2.35]) in the CON group was not significant. With an IRR of 1.22, a future RCT main study would need to observe 793 acute time-loss injuries during match-play, in order to have a power of 80%. CONCLUSIONS A large-scaled RCT is required to definitively test for beneficial or harmful effects of a lighter, smaller football in adolescent female football.
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Affiliation(s)
- Mette K Zebis
- Department of Physiotherapy and Occupational Therapy, Faculty of Health and Technology, Metropolitan University College, Copenhagen, Denmark - .,Gait Analysis Laboratory, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark -
| | - Kristian Thorborg
- Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark
| | - Lars L Andersen
- National Research Center for the Working Environment, Copenhagen, Denmark.,Physical Activity and Human Performance, Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Merete Møller
- Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Karl B Christensen
- Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel B Clausen
- Department of Physiotherapy and Occupational Therapy, Faculty of Health and Technology, Metropolitan University College, Copenhagen, Denmark.,Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark
| | - Per Hölmich
- Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark
| | - Niels Wedderkopp
- Sport Medicine Clinic, Department of Orthopedic, Hospital of Lillebaelt, Institute of Regional Health Service Research and Center for Research in Childhood Health, IOB, University of Southern Denmark, Odense, Denmark.,Department of Psychology and Sport Science, Murdoch University, Perth, Australia
| | - Thomas B Andersen
- Department of Public Health, Section for Sport Science, Aarhus University, Aarhus, Denmark
| | - Peter Krustrup
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.,Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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Ørntoft C, Larsen MN, Andersen TB, Rasmussen LS, Póvoas SCA, Randers MB, Krustrup P. Technical Actions, Heart Rate, and Locomotor Activity in 7v7 and 8v8 Games for Female Youth Soccer Players. J Strength Cond Res 2016; 30:3298-3303. [PMID: 27050242 DOI: 10.1519/jsc.0000000000001434] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ørntoft, C, Larsen, MN, Andersen, TB, Rasmussen, LS, Póvoas, SCA, Randers, MB, and Krustrup, P. Technical actions, heart rate, and locomotor activity in 7v7 and 8v8 games for female youth soccer players. J Strength Cond Res 30(12): 3298-3303, 2016-The purpose of this study was to evaluate technical performance, heart rate (HR), and activity profile in 7v7 and 8v8 soccer games for 9- to 10-year-old girls (U11). A total of 24 female youth players participated in the study, all playing 20-minute 7v7 and 8v8 games with 160 and 223 m per player, respectively. Technical actions, HR, and activity profile were measured during the games using video filming, HR monitors, and 5-Hz Global positioning system (GPS) units. The number of technical actions was higher in 7v7 than in 8v8 games (34 ± 19 vs. 28 ± 14; p = 0.03; d = 0.37), as was the number of successful actions (25 ± 16 vs. 20 ± 12; p = 0.01; d = 0.35), with no difference in success rate for technical actions (70 ± 13 vs. 69 ± 14%; p = 0.63; d = 0.07). No differences were found between 7v7 and 8v8 in total distance covered (1,574 ± 251 and 1,622 ± 281 m; p = 0.66; d = 0.18), peak speed (19.5 ± 2.6 and 20.7 ± 1.5 km·h; p = 0.16; d = 0.56), mean HR values (85 ± 5 and 86 ± 6%HRpeak; p = 0.85; d = 0.18), and time of >90% HRpeak (37 ± 16 and 35 ± 14% of playing time; p = 0.70; d = 0.13). Distance covered at the highest running speeds of >16 km·h was lower in 7v7 than in 8v8 games (34 ± 24 vs. 63 ± 34 m; p = 0.018; d = 0.98), as was the number of entries into this speed zone (8 ± 5 vs. 13 ± 7; p = 0.006; d = 0.82). In conclusion, more technical actions and successful actions were observed in 7v7 than in 8v8 games, but players covered more ground with high-speed running in 8v8 games. This study also revealed that HR values were high in both game formats for U11 adolescent female players, with no difference between formats.
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Affiliation(s)
- Christina Ørntoft
- 1Department of Nutrition, Exercise and Sports, Copenhagen Centre for Team Sport and Health, University of Copenhagen, Copenhagen, Denmark; 2Department of Public Health and Sport Science, Aarhus University, Aarhus, Denmark; 3Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University Institute of Maia, ISMAI, Maia, Portugal; and 4Sport and Health Sciences, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, United Kingdom
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Toft U, Andersen TB, Bloch P, Winkler LL, Glümer C. The quantitative evaluation of the Health and Local Community Project (SoL). Eur J Public Health 2016. [DOI: 10.1093/eurpub/ckw171.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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16
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Andersen TB, Krustrup P, Bendiksen M, Orntoft CO, Randers MB, Pettersen SA. Kicking Velocity and Effect on Match Performance When using a Smaller, Lighter Ball in Women's Football. Int J Sports Med 2016; 37:966-972. [PMID: 27551936 DOI: 10.1055/s-0042-109542] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The present study evaluated the effect of a smaller, lighter ball on kicking speed and technical-tactical and physical match performance in high-level adult female footballers. In the laboratory test setting, the peak ball velocity was 6% higher with the new ball (NB) than the standard ball (SB) (26.5±0.5 vs. 25.1±0.5 m·s-1, p<0.05). However, during match-play, no differences were observed in mean heart rate (87±5 vs. 87±5%HRmax; p>0.05), blood lactate (90 min: 4.7±1.7 and 4.0±1.7 mmol·l-1; p>0.05), total distance covered (10.6±0.9 and 10.4±0.8 km; p>0.05), intense running (>16 km/h) (2.08±0.42 and 1.94±0.38 km; p>0.05) and match-induced decrement in Yo-Yo IR1 performance (28 vs. 31%, respectively, p<0.05) using NB compared to SB. Likewise, no difference was observed in the number of short, medium-range or long passes during matches played with the 2 ball types, and there was no difference in passing success rate (NB: 68±1% and SB: 68±1%, p>0.05). In conclusion, high-level adult female footballers had a higher kicking speed when using a smaller, lighter ball, but no differences were observed during match-play with the 2 ball types in respect of technical-tactical and physical match performance. The physical loading was high for the players when playing with both ball types.
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Affiliation(s)
- T B Andersen
- Department of Public Health - Sport Science, Aarhus University, Aarhus, Denmark
| | - P Krustrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen Centre for Team Sport and Health, Copenhagen, Denmark
| | - M Bendiksen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen Centre for Team Sport and Health, Copenhagen, Denmark
| | - C O Orntoft
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen Centre for Team Sport and Health, Copenhagen, Denmark
| | - M B Randers
- Nutrition Exercise and Sports, University Cobehagen, Copenhagen, Denmark
| | - S A Pettersen
- School of Sport Sciences, University of Tromsoe, the Arctic University, Tromsoe, Norway
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Randers MB, Andersen TB, Rasmussen LS, Larsen MN, Krustrup P. Effect of game format on heart rate, activity profile, and player involvement in elite and recreational youth players. Scand J Med Sci Sports 2015; 24 Suppl 1:17-26. [PMID: 24944130 DOI: 10.1111/sms.12255] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/16/2014] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to evaluate activity profile, aerobic load, and player involvement in two game formats of recreational and elite youth football for two age groups. A total of 152 youth players participated, with 45 U10 players playing 5v5 and 8v8 games, and 41 U13 players playing 8v8 and 11v11 (20 min) games. Activity profile, heart rate (HR), and technical actions were measured during all games using 10 Hz GPS, video filming, and HR monitors. For U10, no difference was found in total distance covered (1754 ± 237 vs 1771 ± 314 m, P = 0.650, d = 0.06), whereas mean HR (174 ± 10 vs 168 ± 12 bpm, P = 0.001, d = 0.59) and number of technical actions (65.1 ± 24.0 vs 36.9 ± 20.4, P 0.001, d = 1.27) were higher in 5v5 than in 8v8. For U13, lower total distance covered (1821 ± 325 vs 2038 ± 328 m, P < 0.001, d = 0.66) and higher number of technical actions (36.2 ± 14.9 vs 26.9 ± 14.1, P < 0.001, d = 0.64) were observed in 8v8 than in 11v11, with no difference in mean HR (170 ± 10 vs 171 ± 10 bpm, P = 0.679, d = 0.10). In conclusion, HR is high in youth football matches irrespective of the level of play and the game format. Playing with fewer players on smaller pitches results in minor changes to the physical loading but elevates the technical involvement of youth players both at elite level and recreational level.
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Affiliation(s)
- M B Randers
- Department of Nutrition, Exercise and Sports, Copenhagen Centre for Team Sport and Health, University of Copenhagen, Copenhagen, Denmark
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18
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Andersen TB, Bendiksen M, Pedersen JM, Ørntoft C, Brito J, Jackman SR, Williams CA, Krustrup P. Kicking velocity and physical, technical, tactical match performance for U18 female football players--effect of a new ball. Hum Mov Sci 2012; 31:1624-38. [PMID: 23158018 DOI: 10.1016/j.humov.2012.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 07/12/2012] [Accepted: 07/15/2012] [Indexed: 10/27/2022]
Abstract
We investigated kicking velocity and physical, technical, and tactical match performance for under-18 (U18) female football players and evaluated the effect of using a newly developed lighter smaller ball. Ten regional league teams participated. Maximal ball velocity was 4±1% higher when kicking the new ball (NB) compared with the standard ball (SB) in a laboratory testing situation (23.2±0.4 vs. 22.4±0.3 ms(-1); p<.05). Mean HR was similar during games with NB and SB (169±2 vs. 170±2 bmin(-1); p>.05), but lower-limb muscular RPE was lower with NB (4.2±0.4 vs. 5.2±0.3; p<.05). The number of activity changes (1387±76 vs. 1401±55), total distance covered (9.09±0.25 vs. 9.11±0.25 km) and high-intensity running (1.04±0.08 vs. 1.11±0.07 km) were not different between NB and SB (p>.05). High-intensity running decreased (p<.05) from 0-20 to 60-80 min with NB (34%) and SB (37%). The number and success rate of long and short passes did not differ between NB and SB (p>.05). In conclusion, physiological demands were high in youth female football games, and decrements in running performance occurred towards the end of games. The players kicked faster and reported lower muscular exertion during games played with a lighter smaller ball, but locomotor activities, heart rate and overall technical-tactical game performance remained unaffected.
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Affiliation(s)
- Thomas B Andersen
- Department of Sport Science, University of Aarhus, Dalgas Avenue 4, DK-8000 Aarhus C, Denmark
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Andersen TB, Bozhevolnyi SI, Markey L, Dereux A. Fiber-pigtailed temperature sensors based on dielectric-loaded plasmonic waveguide-ring resonators. Opt Express 2011; 19:26423-26428. [PMID: 22274227 DOI: 10.1364/oe.19.026423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate optical fiber-pigtailed temperature sensors based on dielectric-loaded surface plasmon-polariton waveguide-ring resonators (DLSPP-WRRs), whose transmission depends on the ambient temperature. The DLSPP-WRR-based temperature sensors represent polymer ridge waveguides (~1×1 µm(2) in cross section) forming 5-µm-radius rings coupled to straight waveguides fabricated by UV-lithography on a 50-nm-thick gold layer atop a 2.3-µm-thick CYTOP layer covering a Si wafer. A broadband light source is used to characterize the DLSPP-WRR wavelength-dependent transmission in the range of 1480-1600 nm and to select the DLSPP-WRR component for temperature sensing. In- and out-coupling single-mode optical fibers are then glued to the corresponding access (photonic) waveguides made of 10-µm-wide polymer ridges. The sample is heated from 21°C to 46 °C resulting in the transmission change of ~0.7 dB at the operation wavelength of ~1510 nm. The minimum detectable temperature change is estimated to be ~5.1∙10(-3) °C for the bandwidth of 1 Hz when using standard commercial optical detectors.
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Affiliation(s)
- Thomas B Andersen
- Institute of Technology and Innovation (ITI), University of Southern Denmark, Odense M, Denmark
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20
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Abstract
The kicking skill of the individual player is of great importance in soccer, and two parameters can be identified as being important in soccer kicking--achieving high speed of the ball and accuracy of performance. The purpose of the current study was to examine the influence of different speeds of approach on the maximal speed of the ball when kicking a stationary ball, and to examine the influence of accuracy of performance on the maximal speed of the ball relevant to a penalty kick. Seven male soccer players kicked for maximal speed of the ball (I) with a self-selected angle and speed of approach, (II) with accuracy demand placed on the subjects, (III) with a straight-line approach of different velocities ranging from 0 m/s to maximal running speed. The maximal speed of the ball was between 28.60 and 34.48 m/s. An accuracy constraint caused the speed of the ball to decline to 85%. With a straight-line approach, the maximal speed of the ball was between 25.64 and 32.26 m/s. When the subjects approached the ball at speeds other than the self-selected speed of approach, the speed of the ball declined, indicating a subject-specific optimal speed of approach.
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Affiliation(s)
- T B Andersen
- Department of Sport Science, University of Aarhus, Aarhus, Denmark.
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Kumar A, Gosciniak J, Andersen TB, Markey L, Dereux A, Bozhevolnyi SI. Power monitoring in dielectric-loaded surface plasmon-polariton waveguides. Opt Express 2011; 19:2972-2978. [PMID: 21369121 DOI: 10.1364/oe.19.002972] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report on propagating mode power monitoring in dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) by measuring the resistance of gold stripes supporting the DLSPPW mode propagation. Inevitable absorption of the DLSPPW mode in metal causes an increase in the stripe temperature and, thereby, in its resistance whose variations are monitored with an external Wheatstone bridge being accurately balanced in the absence of radiation in a waveguide. The investigated waveguide configuration consists of a 1-µm-thick and 10-µm-wide polymer ridges tapered laterally to a 1-µm-wide ridge placed on a 50-nm-thin and 4-µm-wide gold stripe, all supported by a magnesium fluoride substrate. Using single-mode polarization-maintaining fiber for in- and out-coupling of radiation, DLSPPW mode power monitoring at telecom wavelengths is realized with the responsivities of up to ~1.8 µV/µW (showing weak wavelength dependence) being evaluated for a bias voltage of 1 V.
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Affiliation(s)
- Ashwani Kumar
- Institute of Sensors, Signals and Electrotechnics (SENSE), University of Southern Denmark, Niels Bohr Allé 1, DK-5230 Odense M, Denmark
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Andersen TB, Han Z, Bozhevolnyi SI. Compact on-chip temperature sensors based on dielectric-loaded plasmonic waveguide-ring resonators. Sensors (Basel) 2011; 11:1992-2000. [PMID: 22319394 PMCID: PMC3274012 DOI: 10.3390/s110201992] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/14/2011] [Accepted: 01/30/2011] [Indexed: 11/16/2022]
Abstract
The application of a waveguide-ring resonator based on dielectric-loaded surface plasmon-polariton waveguides as a temperature sensor is demonstrated in this paper and the influence of temperature change to the transmission through the waveguide-ring resonator system is comprehensively analyzed. The results show that the roundtrip phase change in the ring resonator due to the temperature change is the major reason for the transmission variation. The performance of the temperature sensor is also discussed and it is shown that for a waveguide-ring resonator with the resonator radius around 5 μm and waveguide-ring gap of 500 nm which gives a footprint around 140 μm2, the temperature sensitivity at the order of 10−2K can be achieved with the input power of 100 μW within the measurement sensitivity limit of a practical optical detector.
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Affiliation(s)
- Thomas B Andersen
- Institute of Technology and Innovation, University of Southern Denmark, Niels Bohrs Alle 1, DK-5230 Odense M, Denmark.
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Madsen JB, Dupont DM, Andersen TB, Nielsen AF, Sang L, Brix DM, Jensen JK, Broos T, Hendrickx MLV, Christensen A, Kjems J, Andreasen PA. RNA aptamers as conformational probes and regulatory agents for plasminogen activator inhibitor-1. Biochemistry 2010; 49:4103-15. [PMID: 20387790 DOI: 10.1021/bi100066j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The hallmark of serpins is the ability to undergo the so-called "stressed-to-relaxed" switch during which the surface-exposed reactive center loop (RCL) becomes incorporated as strand 4 in central beta-sheet A. RCL insertion drives not only the inhibitory reaction of serpins with their target serine proteases but also the conversion to the inactive latent state. RCL insertion is coupled to conformational changes in the flexible joint region flanking beta-sheet A. One interesting serpin is plasminogen activator inhibitor-1 (PAI-1), a fast and specific inhibitor of the serine proteases tissue-type and urokinase-type plasminogen activator. Via its flexible joints' region, native PAI-1 binds vitronectin and relaxed, protease-complexed PAI-1 certain endocytosis receptors. From a library of 35-nucleotides long 2'-fluoropyrimidine-containing RNA oligonucleotides, we have isolated two aptamers binding PAI-1 by the flexible joint region with low nanomolar K(D) values. One of the aptamers exhibited measurable binding to native PAI-1 only, while the other also bound relaxed PAI-1. While none of the aptamers inhibited the antiproteolytic effect of PAI-1, both aptamers inhibited vitronectin binding and the relaxed PAI-1-binding aptamer also endocytosis receptor binding. The aptamer binding exclusively to native PAI-1 increased the half-life for the latency transition to more than 6 h, manyfold more than vitronectin. Contact with Lys124 in the flexible joint region was critical for strong inhibition of the latency transition and the lack of binding to relaxed PAI-1. We conclude that aptamers yield important information about the serpin conformational switch and, because they can compete with high-affinity protein-protein interactions, may provide leads for pharmacological intervention.
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Affiliation(s)
- Jeppe B Madsen
- Danish-Chinese Center for Proteases and Cancer, Aarhus University,10C Gustav Wieds Vej, 8000 Aarhus C, Denmark
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Gosciniak J, Bozhevolnyi SI, Andersen TB, Volkov VS, Kjelstrup-Hansen J, Markey L, Dereux A. Thermo-optic control of dielectric-loaded plasmonic waveguide components. Opt Express 2010; 18:1207-1216. [PMID: 20173944 DOI: 10.1364/oe.18.001207] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report preliminary results on the development of compact (length < 100 microm) fiber-coupled dielectric-loaded plasmonic waveguide components, including Mach-Zehnder interferometers (MZIs), waveguide-ring resonators (WRRs) and directional couplers (DCs), whose operation at telecom wavelengths is controlled via the thermo-optic effect by electrically heating the gold stripes of dielectric-loaded plasmonic waveguides. Strong output modulation (> 20%) is demonstrated with MZI- and WRR-based components, and efficient (approximately 30%) rerouting is achieved with DC switches.
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Affiliation(s)
- Jacek Gosciniak
- Institute of Sensors, Signals and Electrotechnics (SENSE), University of Southern Denmark, Niels Bohrs Allé 1, Odense M, Denmark
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Hansen L, de Zee M, Rasmussen J, Andersen TB, Wong C, Simonsen EB. Anatomy and biomechanics of the back muscles in the lumbar spine with reference to biomechanical modeling. Spine (Phila Pa 1976) 2006; 31:1888-99. [PMID: 16924205 DOI: 10.1097/01.brs.0000229232.66090.58] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN This article describes the development of a musculoskeletal model of the human lumbar spine with focus on back muscles. It includes data from literature in a structured form. OBJECTIVE To review the anatomy and biomechanics of the back muscles related to the lumbar spine with relevance for biomechanical modeling. SUMMARY OF BACKGROUND DATA To reduce complexity, muscle units have been incorporated in an abridged manner, reducing their actions more or less to a single force equivalent. In early models of the lumbar spine, this may have been a necessary step to reduce complexity and, thereby, calculation time. The muscles of the spine are well described in the literature, but mainly qualitatively. Most of the literature provides a description of the structures without precise data of fiber length, muscle length, cross-sectional areas, moment arms, forces, etc. The predicted output of musculoskeletal models is very much dependent on the input parameters. The information needed to improve models consists of better approximations of the attachments to the vertebrae, and more precise data. METHOD Review of literature. RESULTS The predicted output of musculoskeletal models is very much dependent on the input parameters. Moderate changes in the assumed muscle line-of-action (i.e., moment arm) could substantially alter the magnitudes of predicted muscle and spinal forces, while the choice of optimization formulation is less sensitive. CONCLUSIONS Input parameters, moment arms, as well as physiologic cross-sectional areas have a profound effect on the predicted muscle forces. Therefore, it is important to choose the values for moment arm and physiologic cross-sectional area carefully because they are essential input parameters to biomechanical models.
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Affiliation(s)
- Lone Hansen
- Institute of Medical Anatomy, Biomech. and Motor Control, University of Copenhagen, Denmark.
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Essendrop M, Andersen TB, Schibye B. Increase in spinal stability obtained at levels of intra-abdominal pressure and back muscle activity realistic to work situations. Appl Ergon 2002; 33:471-476. [PMID: 12236656 DOI: 10.1016/s0003-6870(02)00028-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this study, sudden load was applied to the trunk and situations with alternating low levels of intra-abdominal pressure (IAP) realistic to work situations were compared. The aim was to see if IAP and the small increases in co-contraction of back muscles that follow are capable of increasing the stiffness of the lumbar spine. Nine subjects participated in ten sudden load situations during which they were asked to hold a box and conduct a percentage of maximal IAP. The hip was fixed and the load was applied horizontally on the trunk. EMG, IAP, and movement of the trunk were measured. It was found that IAP of a size likely to appear in work situations, and the concomitant increase in muscle co-activation increased the spine stiffness. This increase in stiffness decreased the movement caused by the sudden load. These results show that both abdominal- and back muscles may have an important role in stabilising the spine, and in decreasing movements caused by sudden loads likely to appear in numerous work
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Affiliation(s)
- M Essendrop
- Department of Physiology, National Institute of Occupational Health, Copenhagen, Denmark.
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Dörge HC, Andersen TB, Sørensen H, Simonsen EB, Aagaard H, Dyhre-Poulsen P, Klausen K. EMG activity of the iliopsoas muscle and leg kinetics during the soccer place kick. Scand J Med Sci Sports 1999; 9:195-200. [PMID: 10407926 DOI: 10.1111/j.1600-0838.1999.tb00233.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The purpose of the study was to develop a method to record intramuscular electromyogram (EMG) from the iliopsoas muscle and to relate this activity to the kinetics during the soccer place kick. Seven skilled soccer players performed 3 maximal velocity place kicks. The kicks were filmed with a high-speed camera (400 Hz) and EMG recordings were obtained from 5 muscles of the kicking leg, including wire electrodes inserted into the m. iliopsoas. The EMG signals were compared to the kinetics of the kicking leg, which were calculated from the digitised film. The results showed hardly any torque reversal about the hip joint before impact. Angular deceleration of the thigh segment did not increase the angular velocity of the shank (work -3.57 to 0.0%). M. iliopsoas was active during the entire kicking motion (average EMG 65.1-100.9%), even in the period when the thigh was decelerating. Wire electrodes can successfully be applied to EMG recordings of fast unloaded movements.
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Affiliation(s)
- H C Dörge
- Institute of Medical Anatomy C, University of Copenhagen, Denmark
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Jensen S, Andersen AH, Kjeldsen E, Biersack H, Olsen EH, Andersen TB, Westergaard O, Jakobsen BK. Analysis of functional domain organization in DNA topoisomerase II from humans and Saccharomyces cerevisiae. Mol Cell Biol 1996; 16:3866-77. [PMID: 8668204 PMCID: PMC231383 DOI: 10.1128/mcb.16.7.3866] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The functional domain structure of human DNA topoisomerase IIalpha and Saccharomyces cerevisiae DNA topoisomerase II was studied by investigating the abilities of insertion and deletion mutant enzymes to support mitotic growth and catalyze transitions in DNA topology in vitro. Alignment of the human topoisomerase IIalpha and S. cerevisiae topoisomerase II sequences defined 13 conserved regions separated by less conserved or differently spaced sequences. The spatial tolerance of the spacer regions was addressed by insertion of linkers. The importance of the conserved regions was assessed through deletion of individual domains. We found that the exact spacing between most of the conserved domains is noncritical, as insertions in the spacer regions were tolerated with no influence on complementation ability. All conserved domains, however, are essential for sustained mitotic growth of S. cerevisiae and for enzymatic activity in vitro. A series of topoisomerase II carboxy-terminal truncations were investigated with respect to the ability to support viability, cellular localization, and enzymatic properties. The analysis showed that the divergent carboxy-terminal region of human topoisomerase IIalpha is dispensable for catalytic activity but contains elements that specifically locate the protein to the nucleus.
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Affiliation(s)
- S Jensen
- Department of Molecular Biology, University of Aarhus, Denmark
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Andersen TB. Optical aberration functions: derivatives with respect to surface parameters for symmetrical systems. Appl Opt 1985; 24:1122. [PMID: 18217085 DOI: 10.1364/ao.24.001122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Andersen TB. Optical aberration functions: chromatic aberrations and derivatives with respect to refractive indices for symmetrical systems. Appl Opt 1982; 21:4040-4044. [PMID: 20401005 DOI: 10.1364/ao.21.004040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Formulas are presented for the computation of derivatives of the optical aberration functions S, T, V, W, and K with respect to the relative refractive indices, leading to the chromatic aberrations, for symmetrical optical systems. The formulas are suitable for use in computer programs for automatic computation of optical aberration coefficients.
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Affiliation(s)
- T B Andersen
- Copenhagen University Observatory, ster Voldgade 3, DK-1350 Kobenhavn K, Denmark
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Andersen TB. Evaluating rms spot radii by ray tracing: errata. Appl Opt 1982; 21:3237. [PMID: 20396216 DOI: 10.1364/ao.21.003237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Abstract
Simplified formulas are presented for the computation of derivatives of the optical aberration functions S,T,V,W, and K with respect to the axial surface distances for symmetrical optical systems. The formulas are well-suited for implementation in computer programs for automatic computation of optical aberration coefficients.
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Affiliation(s)
- T B Andersen
- Copenhagen University Observatory, 0ster Voldgade 3, DK-1350 Kobenhavn K, Denmark
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Abstract
The computation of rms spot radii from ray trace calculations is investigated in relation to the number of rays to be traced to achieve a prescribed accuracy. It is shown that the usual simple averaging formulas will only have as limits for infinitely many rays the correct center of mass and gyration radius if a square ray grid point distribution is used throughout the limiting process. For other ray distributions the ray trace data are given weight according to the local grid point density. Using the simple averaging formulas deviations in computed image radii of 15-20% may be encountered due solely to variations in grid point distributions. A computing method is suggested using a fourth-order quadrature formula giving 1% accuracy with ~20 rays and 0.01% accuracy with ~40-50 rays.
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Andersen TB. Optical aberration functions: computation of caustic surfaces and illuminance in symmetrical systems. Appl Opt 1981; 20:3723-3728. [PMID: 20372252 DOI: 10.1364/ao.20.003723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The use of automatically computed aberration functions for an exact determination of the geometric illuminance and caustic surfaces is demonstrated. Numerical results for two optical systems studied using aberration coefficients to the thirteenth order are presented.
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Abstract
FORTRAN computer subroutines for the automatic computation of the optical aberration functions S, T, V, W, and K to the 15th order for rotationally symmetric systems are presented. The routines may be conveniently extended toward higher orders.
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Abstract
The use of automatically computed aberration coefficients of arbitrary order for an exact determination of the surface of best focus of a symmetrical system, by minimizing the gyration radius of the spot diagram, is demonstrated. For the two optical systems studied, a Schmidt camera and a Ritchey-Chrétien telescope, the results from the exact model are found to be significantly different from the paraxial approximation predictions.
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Abstract
A method based on ray tracing equations is presented facilitating the computation of polynomial functions that predict the x and y intercepts, direction tangents, and optical path length of an arbitrary skew ray on a defocused image surface. The optical systems considered may contain surfaces of general nonrotationally symmetric figure and orientation, refracting as well as reflecting, including plane diffraction gratings. The classical aberration coefficient equations are a subset of these polynomials. The method can, without hard programming work, be extended to arbitrarily high orders.
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