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Augustus S, Hudson PE, Smith N. Multiplanar lumbar, pelvis and kick leg sequencing during soccer instep kicking from different approach angles. J Biomech 2024; 163:111920. [PMID: 38198931 DOI: 10.1016/j.jbiomech.2023.111920] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/14/2023] [Accepted: 12/31/2023] [Indexed: 01/12/2024]
Abstract
Multiplanar kinematic and kinetic sequencing from different approach angles can highlight how soccer players perform fast and accurate kicks. This study therefore aimed to a) determine multiplanar torso, pelvis and kick leg sequencing during instep kicks and b) highlight the effect of different approach angles on these sequencing patterns. Twenty male soccer players (mass 77.9 ± 6.5 kg, height 1.71 ± 0.09 m, age 23.2 ± 3.7 years) performed kicks from self-selected (∼30-45°), straight (0°) and wide (67.5°) approaches and multiplanar lumbo-pelvic, hip and knee angular velocities, moments and powers were derived from 3D motion analysis. The results suggest tension arc release between the upper and lower body functions as a two-stage mechanism. The first phase of arc release was characterised by increases in concentric hip flexion and transverse lumbo-pelvic velocities towards the ball. The second phase was characterised by increasing concentric lumbo-pelvic flexion and knee extension work to angularly accelerate the kicking knee towards foot-to-ball contact. Further, alterations in kinematic and kinetic sequencing helped maintain performance (ball and foot velocities at ball contact) and accuracy at approach angles other than self-selected. These findings can help coaches and practitioners design effective training practices.
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Affiliation(s)
- Simon Augustus
- Department of Applied and Human Sciences, Kingston University, London, UK.
| | - Penny E Hudson
- School of Sport and Exercise Sciences, University of Chichester, Chichester, UK
| | - Neal Smith
- School of Sport and Exercise Sciences, University of Chichester, Chichester, UK
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Augustus S, Amca AM, Hudson PE, Smith N. Choice of low-pass filter influences practical interpretation of ball kicking motions: the effect of a time-frequency filter method. Sports Biomech 2023; 22:1412-1429. [PMID: 32875948 DOI: 10.1080/14763141.2020.1805507] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 07/31/2020] [Indexed: 10/23/2022]
Abstract
When studying ball kicking, conventional low-pass filters may distort kick leg kinematics near the time of foot-to-ball contact, leading to flawed practical interpretation of the skill. Time-frequency filters are a viable alternative but are not widely used. This study compared a fractional Fourier filter (FrFF) with conventional filters (CF) methods for estimating common parameters used to define kicking performance. Instep kicks from 23 experienced soccer players were captured by 3D motion analysis (1000 Hz), and kick leg foot velocities, knee angular velocities and ankle dorsi-plantarflexion angles compared between the FrFF and variations of a Butterworth CF. The FrFF and CFs using a higher cut-off frequency (>70 Hz) successfully detected lower leg motion prior to, during and following impact, whereas CFs with low cut-off frequencies (<20 Hz) attenuated motion near impact. Truncating data at impact provided valid pre-impact kinematics, but ignored information thereafter. Rather than decelerating the lower leg to conserve accuracy, 'kicking through the ball' should be considered a valid coaching cue. Further, controlling ankle plantar flexion to ensure efficient impact mechanics may be important for skilled kicking. Practitioners should consider how choice of filter will affect their data, and use of time-frequency methods can help inform empirically grounded coaching practices.
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Affiliation(s)
- Simon Augustus
- Chichester Institute of Sport, University of Chichester, Chichester, UK
| | | | - Penny E Hudson
- Chichester Institute of Sport, University of Chichester, Chichester, UK
| | - Neal Smith
- Chichester Institute of Sport, University of Chichester, Chichester, UK
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Jones S, Nunome H, Augustus S, Peacock JCA, Ball K, Bezodis NE. Understanding the effects of ball orientation in Rugby Union place kicking: the preferences of international kickers and the kinematics of the foot-ball impact. Sports Biomech 2022:1-16. [PMID: 36579928 DOI: 10.1080/14763141.2022.2159507] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 12/12/2022] [Indexed: 12/30/2022]
Abstract
Rugby Union place kicking is influential to match outcome. Previous research has analysed kicker motion prior to ball contact in detail, but ball orientation and the impact phase are typically ignored. This study aims to firstly identify the ball orientations used by international place kickers, and secondly to experimentally analyse the foot-ball interaction in trained kickers using different ball orientations. Overall, 25.5% of the international kickers used an upright ball orientation, 27.5% used a diagonal orientation and 47.1% used a horizontal orientation. However, ball orientation preference was not significant in predicting kick outcome in a binomial logistic regression model. To address the second aim, ball orientation was experimentally manipulated and lower limb and ball kinematics were captured using high-speed (4000 Hz) video. Whilst the impact location on the ball differed significantly between most ball orientation conditions, the impact location relative to the global vertical was largely consistent across all conditions. This was likely due to kickers adopting very consistent lower limb kinematics, although the shank and ankle angles at impact were affected by ball orientation conditions for some kickers. Impact durations also differed between some conditions, although this did not appear to affect the impact efficiency.
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Affiliation(s)
- Sam Jones
- Applied Sports, Technology, Exercise and Medicine (A-STEM) Research Centre, Swansea University, Swansea, UK
| | - Hiroyuki Nunome
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan
| | - Simon Augustus
- Department of Applied Human Sciences, Kingston University, London, UK
| | - James C A Peacock
- Institute for Health & Sport, Victoria University, Footscray, Australia
| | - Kevin Ball
- Institute for Health & Sport, Victoria University, Footscray, Australia
| | - Neil E Bezodis
- Applied Sports, Technology, Exercise and Medicine (A-STEM) Research Centre, Swansea University, Swansea, UK
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Augustus S, Hudson PE, Smith N. Defining movement strategies in soccer instep kicking using the relationship between pelvis and kick leg rotations. Sports Biomech 2022:1-12. [PMID: 35903959 DOI: 10.1080/14763141.2022.2106297] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 07/20/2022] [Indexed: 10/16/2022]
Abstract
Growing evidence suggests skilled ball kickers use distinct pelvis and kick leg strategies to achieve successful performance. However, since the interaction between different strategies remains unexplored, the aims of this study were to a) examine relationships between pelvis and kick leg rotations in male players performing soccer instep kicks and b) classify different 'types' of kickers based on the observed movement strategies. Twenty semi-professional players performed kicks for maximal speed and accuracy, and kick leg and pelvis kinematics were analysed using 3D motion capture (1000 Hz). A strong relationship was found between change in pelvis transverse angular velocity and thigh-knee angular velocity ratio upon ball contact (r = 0.76, p < 0.001), and participants were categorised by their location on kick leg (thigh-knee) and pelvis (maintainer-reverser) continuums. Knowledge of a player's preferred strategy can inform departure from 'one size fits all' technical and conditioning training practices towards more individualised approaches. For example, pelvis maintainer-thigh dominant kickers might benefit from focus towards the concentric capabilities of the hip flexors, whereas reverser-knee dominant kickers might benefit from developing the ability to decelerate the pelvis and thigh to induce motion-dependent angular acceleration of the lower leg towards the ball.
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Affiliation(s)
- Simon Augustus
- Department of Applied and Human Sciences, Kingston University, London, UK
| | - Penny E Hudson
- Chichester Institute of Sport, University of Chichester, West Sussex, UK
| | - Neal Smith
- Chichester Institute of Sport, University of Chichester, West Sussex, UK
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Augustus S, Hudson PE, Harvey N, Smith N. Whole-body energy transfer strategies during football instep kicking: implications for training practices. Sports Biomech 2021:1-16. [PMID: 34313184 DOI: 10.1080/14763141.2021.1951827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/30/2021] [Indexed: 10/20/2022]
Abstract
Knowledge of whole-body energy transfer strategies during football instep kicking can help inform empirically grounded training practices. The aim of this study was thus to investigate energy transfer strategies of 15 semi-professional players performing kicks for speed and accuracy. Three-dimensional kinematics and GRFs (both 1000 Hz) were incorporated into segment power analyses to derive energy transfers between the support leg, torso, pelvis and kick leg throughout the kick. Energy transferred from support leg (r = 0.62, P = 0.013) and torso (r = 0.54, P = 0.016) into the pelvis during tension arc formation and leg cocking was redistributed to the kick leg during the downswing (r = 0.76, P < 0.001) and were associated with faster foot velocities at ball contact. This highlights whole-body function during instep kicking. Of particular importance were: (a) regulating support leg energy absorption, (b) eccentric formation and concentric release of a 'tension arc' between the torso and kicking hip, and (c) coordinated proximal to distal sequencing of the kick leg. Resistance exercises that replicate the demands of these interactions may help develop more powerful kicking motions and varying task and/or environmental constraints might facilitate development of adaptable energy transfer strategies.
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Affiliation(s)
- Simon Augustus
- Chichester Institute of Sport, University of Chichester, Chichester, West Sussex, UK
| | - Penny E Hudson
- Chichester Institute of Sport, University of Chichester, Chichester, West Sussex, UK
| | | | - Neal Smith
- Chichester Institute of Sport, University of Chichester, Chichester, West Sussex, UK
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Augustus S, Hudson PE, Smith N. The effect of approach velocity on pelvis and kick leg angular momentum conversion strategies during football instep kicking. J Sports Sci 2021; 39:2279-2288. [PMID: 34034623 DOI: 10.1080/02640414.2021.1929008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
During football instep kicking, whole-body deceleration during the final stride has been associated with greater kick leg angular momentum and enhanced foot and ball velocities, but the influence of approach velocity on these mechanisms is unknown. This study assessed how approach velocity affects momentum conversion strategies of experienced players performing fast and accurate kicks. Eleven semi-professional footballers performed instep kicks from self-selected (3.34 ± 0.43 m/s), fast (3.71 ± 0.33 m/s) and slow (2.77 ± 0.32 m/s) approaches. Kicking motions and ground reaction forces under the support leg were captured using 3D motion analysis (1000 Hz). The players responded to perturbations in approach velocity by using the support leg to regulate whole-body deceleration and create ideal conditions for co-ordinated pelvic and kick leg momentums during the downswing. Further, the pelvis was key for generating transverse momentum at the kick leg, but the participants displayed distinctly different pelvis transverse rotation strategies. Identification of these inter-individual strategies may provide a basis for technical and strength training practices to be tailored for individual players. Future research might investigate if training practices that expose footballers to varying approach velocities of between 2.5 and 4.0 m/s promotes development of movement strategies that are robust to perturbations in approach conditions.
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Affiliation(s)
- Simon Augustus
- Chichester Institute of Sport, University of Chichester, Chichester, UK
| | - Penny E Hudson
- Chichester Institute of Sport, University of Chichester, Chichester, UK
| | - Neal Smith
- Chichester Institute of Sport, University of Chichester, Chichester, UK
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Augustus S, Amca AM, Hudson PE, Smith N. Improved accuracy of biomechanical motion data obtained during impacts using a time-frequency low-pass filter. J Biomech 2020; 101:109639. [PMID: 31983403 DOI: 10.1016/j.jbiomech.2020.109639] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/08/2020] [Accepted: 01/12/2020] [Indexed: 11/28/2022]
Abstract
Biomechanical motion data involving impacts are not adequately represented using conventional low-pass filters (CF). Time-frequency filters (TFF) are a viable alternative, but have been largely overlooked by movement scientists. We modified Georgakis and Subramaniam's (2009) fractional Fourier filter (MFrFF) and demonstrated it performed better than CFs for obtaining lower leg accelerations during football instep kicking. The MFrFF displayed peak marker accelerations comparable to a reference accelerometer during foot-to-ball impact (peak % error = -5.0 ± 11.4%), whereas CFs severely underestimated these peaks (30-70% error). During the non-impact phases, the MFrFF performed comparably to CFs using an appropriate (12-20 Hz) cut-off frequency (RMSE = 37.3 ± 7.6 m/s2 vs. 42.1 ± 11.4 m/s2, respectively). Since accuracy of segmental kinematics is fundamental for understanding human movement, the MFrFF should be applied to a range of biomechanical impact scenarios (e.g. locomotion, landing and striking motions) to enhance the efficacy of study in these areas.
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Affiliation(s)
- Simon Augustus
- Chichester Institute of Sport, University of Chichester, Chichester, United Kingdom.
| | | | - Penny E Hudson
- Chichester Institute of Sport, University of Chichester, Chichester, United Kingdom
| | - Neal Smith
- Chichester Institute of Sport, University of Chichester, Chichester, United Kingdom
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Lake J, Augustus S, Austin K, Comfort P, McMahon J, Mundy P, Haff GG. The reliability and validity of the bar-mounted PUSH Band TM 2.0 during bench press with moderate and heavy loads. J Sports Sci 2019; 37:2685-2690. [PMID: 31418312 DOI: 10.1080/02640414.2019.1656703] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The aim of this study was to assess the reliability and validity of the bar-mounted PUSH BandTM 2.0 to determine peak and mean velocity during the bench press exercise with a moderate (60% one repetition maximum [1RM]) and heavy (90% 1RM) load. We did this by simultaneously recording peak and mean velocity using the PUSH BandTM 2.0 and three-dimensional motion capture from participants bench pressing with 60% and 90% 1RM. We used ordinary least products regression to assess within-session reliability and whether the PUSH BandTM 2.0 could accurately predict motion capture velocity. Results showed that PUSH BandTM 2.0 and motion capture peak and mean velocity reliability was acceptable with both loads. While there was a tendency for the PUSH BandTM 2.0 to slightly overestimate peak and mean velocity, there was no fixed bias. However, mean velocity with 60 and 90% 1RM demonstrated proportional bias (differences between predicted and motion capture values increase with magnitude). Therefore, PUSH BandTM 2.0 peak velocity with 60 and 90% 1RM is valid, but mean velocity is not.
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Affiliation(s)
- Jason Lake
- Chichester Institute of Sport, University of Chichester , Chichester , UK
| | - Simon Augustus
- Chichester Institute of Sport, University of Chichester , Chichester , UK
| | - Kieran Austin
- Chichester Institute of Sport, University of Chichester , Chichester , UK
| | - Paul Comfort
- Directorate of Sport, Exercise, and Physiotherapy, University of Salford , Salford , UK
| | - John McMahon
- Directorate of Sport, Exercise, and Physiotherapy, University of Salford , Salford , UK
| | - Peter Mundy
- Centre for Sport, Exercise, and Life Sciences, Coventry University , Coventry , UK
| | - G Gregory Haff
- Directorate of Sport, Exercise, and Physiotherapy, University of Salford , Salford , UK.,Centre for Exercise and Sports Science Research, Edith Cowan University , Joondalup , Australia
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Lake JP, Augustus S, Austin K, Mundy P, McMahon JJ, Comfort P, Haff GG. The Validity of the Push Band 2.0 during Vertical Jump Performance. Sports (Basel) 2018; 6:sports6040140. [PMID: 30400613 PMCID: PMC6316333 DOI: 10.3390/sports6040140] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [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: 09/30/2018] [Revised: 10/30/2018] [Accepted: 11/01/2018] [Indexed: 11/16/2022] Open
Abstract
The Push Band has the potential to provide a cheap and practical method of measuring velocity and power during countermovement vertical jumping (CMJ). However, very little is known about whether it conforms to laboratory-based gold standards. The aim of this study was to assess the agreement between peak and mean velocity and power obtained from the belt-worn Push Band, and derived from three-dimensional motion capture, and vertical force from an in-ground force platform. Twenty-two volunteers performed 3 CMJ on a force platform, while a belt-worn Push Band and a motion capture system (a marker affixed to the Push Band) simultaneously recorded data that enabled peak and mean velocity and power to be calculated and then compared using ordinary least products regression. While the Push Band is reliable, it tends to overestimate peak (9–17%) and mean (24–27%) velocity, and when compared to force plate-derived peak and mean power, it tends to underestimate (40–45%) and demonstrates fixed and proportional bias. This suggests that while the Push Band may provide a useful method for measuring peak and mean velocity during the CMJ, researchers and practitioners should be mindful of its tendency to systematically overestimate and that its measures of peak and mean power should not be used.
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Affiliation(s)
- Jason P Lake
- Chichester Institute of Sport, University of Chichester, Chichester PO19 6PE, UK.
| | - Simon Augustus
- Chichester Institute of Sport, University of Chichester, Chichester PO19 6PE, UK.
| | - Kieran Austin
- Chichester Institute of Sport, University of Chichester, Chichester PO19 6PE, UK.
| | - Peter Mundy
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry CV1 5FB, UK.
| | - John J McMahon
- Directorate of Sport, Exercise and Physiotherapy, University of Salford, Frederick Road, Salford M6 6PU, UK.
| | - Paul Comfort
- Directorate of Sport, Exercise and Physiotherapy, University of Salford, Frederick Road, Salford M6 6PU, UK.
| | - Guy G Haff
- Centre for Exercise and Sports Science Research, Edith Cowan University, Joondalup, Western Australia WA 6027, Australia.
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Augustus S, Mundy P, Smith N. Support leg action can contribute to maximal instep soccer kick performance: an intervention study. J Sports Sci 2016; 35:89-98. [DOI: 10.1080/02640414.2016.1156728] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
2007 Background:. The background rate of CNS hemorrhage (CH) in cancer patients with brain metastases not receiving bevacizumab (BV) treatment is 5%-29%, depending on tumor type. Patients with CNS metastases were routinely excluded from most BV late-stage clinical trials, following the occurrence of CH in one hepatocellular carcinoma patient with occult CNS metastasis in a BV phase I trial. In this particular tumour type, up to 87.5% has been reported as a background rate of CH without BV use. Available safety information in BV-treated patients with CNS metastases has been reviewed to determine whether the exclusion of these patients from trials is still justified. Methods: A retrospective exploratory analysis was conducted using safety data from three datasets: A.) 13 randomized controlled phase II or III trials (RCTs); B.) Two ongoing open-label trials MO19391 (ATHENA) and MO19390 (SAIL). While patients with known CNS metastases, based on imaging or clinical signs and symptoms, were excluded from trial in A and B datasets, patients who were found to have CNS lesions had either unrecognized CNS metastases at study entry or had developed these during the trial.; C.) 2 ongoing open-label studies AVF3752g and AVF3671g in patients with NSCLC, where inclusion of patients with treated CNS metastases was allowed. Incidence of CH in patients with brain metastases was quantified in each dataset. Results: A.) In 13 RCTs, with a total of 8443 patients with locally advanced, unresectable, or metastatic breast, renal, pancreatic, colorectal cancer, or NSCLC, brain metastases were identified in 187 patients (91 in BV-arms and 96 in control arm). Three of 91 (3.29%) BV-treated patients developed grade 4 CH, and one in 96 patients in the control arm (1.04%) developed grade 5 CH; B.) In open-label studies no CH was reported in 68 patients with CNS metastases, out of 3,252 patients enrolled. C.) In two studies in patients with treated CNS metastases, one subject in 83 (1.2%) BV treated patients developed a grade 2 CH. Conclusions: In this retrospective review, the rates of CH in BV-treated patients with CNS metastases is low, and appears consistent with historical rates of CH in these patient populations. Ongoing trials are expected to provide additional data regarding the risk of CH in patients with primary and metastatic CNS tumors. [Table: see text]
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Affiliation(s)
- U. P. Rohr
- F. Hoffmann-La Roche, Basel, Switzerland; Genentech, Inc., South San Francisco, CA
| | - S. Augustus
- F. Hoffmann-La Roche, Basel, Switzerland; Genentech, Inc., South San Francisco, CA
| | - S. F. Lasserre
- F. Hoffmann-La Roche, Basel, Switzerland; Genentech, Inc., South San Francisco, CA
| | - P. Compton
- F. Hoffmann-La Roche, Basel, Switzerland; Genentech, Inc., South San Francisco, CA
| | - J. Huang
- F. Hoffmann-La Roche, Basel, Switzerland; Genentech, Inc., South San Francisco, CA
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Mark PJ, Augustus S, Hewitt DP, Waddell BJ. 203. Partial progesterone withdrawal during late gestation increases placental expression of 11β-HSD1 in the rat. Reprod Fertil Dev 2008. [DOI: 10.1071/srb08abs203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Fetal glucocorticoid excess programs adverse outcomes in adult offspring, including hypertension, obesity and insulin resistance. Access of maternal glucocorticoids to the fetus is regulated by the placental glucocorticoid barrier which consists of the 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) enzyme and P-glycoprotein (Abcb1). Both proteins act to reduce fetal and placental exposure to active, circulating glucocorticoids. In addition, placental expression of 11β-HSD1 is thought to limit the effectiveness of the barrier by local reactivation of inert glucocorticoids. The present study measured expression of placental 11β-HSD1 and 11β-HSD2 in normal rat pregnancy and after either partial progesterone withdrawal or treatment with dexamethasone, both of which reduce fetal growth. Placentas were collected and dissected into their morphologically- and functionally-distinct zones (junctional and labyrinth) on days 16 and 22 of normal pregnancy (term = 23 days) and after either dexamethasone treatment (0.75 μg/mL in drinking water from day 13) or ovariectomy (day 16) plus full oestrogen and partial progesterone replacement (to approximately one-third of day 22 levels). Junctional and labyrinth zone expression of 11β-HSD1 and 11β-HSD2 mRNA were determined by qRT–PCR. Labyrinthine expression of 11β-HSD1 increased markedly between days 16 and 22 and there was a concomitant decrease in labyrinthine 11β-HSD2 expression. Dexamethasone administration had no effect on the expression of either 11β-HSD isoform in either placental zone. Partial progesterone withdrawal increased 11β-HSD1 expression in both placental zones (1.9 and 3.1-fold in LZ and JZ respectively, P < 0.05), but had no effect on 11β-HSD2 levels. In conclusion, these data confirm the pattern of placental 11β-HSD isoform expression in late rat pregnancy and suggest that that labyrinth zone 11β-HSD1 is normally suppressed by progesterone. Thus, the normal pre-partum decline in circulating progesterone may provide a key stimulus for the marked rise in labyrinth zone 11β-HSD1 that occurs between days 16 and 22 of pregnancy.
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Augustus S. Come out and play. Nurs Mirror Midwives J 1971; 133:37-9. [PMID: 5210101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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