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Researchers in neuromechanics should upgrade their statistical toolbox. We propose linear mixed-effects models in place of commonly used statistical tests to better capture subject-specific baselines and treatment-associated effects that naturally occur in neuromechanics. Researchers can use this approach to handle sporadic missing data, avoid the assumption of conditional independence in observations, and successfully model complex experimental protocols.
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Projetos de Pesquisa , Humanos , Modelos LinearesRESUMO
Riding uphill presents a challenge to competitive and recreational cyclists. Based on only limited evidence, some scientists have reported that tilting the saddle nose down improves uphill-cycling efficiency by as much as 6%. PURPOSE: here, we investigated if simply tilting the saddle nose down increases efficiency during uphill cycling, which would presumably improve performance. METHODS: nineteen healthy, recreational cyclists performed multiple 5 min trials of seated cycling at ~ 3 W kg-1 on a large, custom-built treadmill inclined to 8° under two saddle-tilt angle conditions: parallel to the riding surface and 8° nose down. We measured subjects' rates of oxygen consumption and carbon dioxide production using an expired-gas analysis system and then calculated their average metabolic power during the last two min of each 5 min trial. RESULTS: we found that, compared to the parallel-saddle condition, tilting the saddle nose down by 8° improved gross efficiency from 0.205 to 0.208-an average increase of 1.4% ± 0.2%, t = 5.9, p < 0.001, CI95% [0.9 to 1.9], dz = 1.3. CONCLUSION: our findings are relevant to competitive and recreational cyclists and present an opportunity for innovating new devices and saddle designs that enhance uphill-cycling efficiency. The effect of saddle tilt on other slopes and the mechanism behind the efficiency improvement remain to be investigated.
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Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Esforço Físico/fisiologia , Postura/fisiologia , Equipamentos Esportivos , Adulto , Teste de Esforço , Feminino , Humanos , Masculino , Consumo de OxigênioRESUMO
Patients with hypertrophic cardiomyopathy, particularly young adults, can die from arrhythmia, but the mechanism underlying abnormal rhythm formation remains unknown. C57Bl6 × CBA/Ca mice carrying a cardiac actin ( ACTC) E99K (Glu99Lys) mutation reproduce many aspects of human hypertrophic cardiomyopathy, including increased myofilament Ca2+ sensitivity and sudden death in a proportion (up to 40%) of young (28-40 day old) animals. We studied the hearts of transgenic (TG; ACTC E99K) mice and their non-TG (NTG) littermates when they were in their vulnerable period (28-40 days old) and when they were adult (8-12 wk old). Ventricular myocytes were isolated from the hearts of TG and NTG mice at these two time points. We also examined the hearts of mice that died suddenly (SCD). SCD animals had approximately four times more collagen compared with age-matched NTG mice, yet myocyte cell size was normal. Young TG mice had double the collagen content of NTG mice. Contraction and Ca2+ transients were greater in cells from young TG mice compared with their NTG littermates but not in cells from adult mice (TG or NTG). Cells from young TG mice had a greater propensity for Ca2+ waves than NTG littermates, and, despite similar sarcoplasmic reticulum Ca2+ content, a proportion of these cells had larger Ca2+ spark mass. We found that the probability of SCD in young TG mice was increased when the mutation was expressed in animals with a CBA/Ca2+ background and almost eliminated in mice bred on a C57Bl6 background. The latter TG mice had normal cellular Ca2+ homeostasis. NEW & NOTEWORTHY Mice with the actin Glu99Lys hypertrophic cardiomyopathy mutation ( ACTC E99K) are prone to sudden cardiac death around 40 days, associated with increased Ca2+ transients, spark mass, and fibrosis. However, adult survivors have normal Ca2+ transients and spark density accompanied by hypertrophy. Penetrance of the sudden cardiac death phenotype depends on the genetic background of the mouse. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/calcium-regulation-in-e99k-mouse-heart/ .
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Sinalização do Cálcio , Cardiomiopatia Hipertrófica/metabolismo , Morte Súbita Cardíaca , Patrimônio Genético , Actinas/genética , Fatores Etários , Animais , Cardiomiopatia Hipertrófica/genética , Células Cultivadas , Colágeno/metabolismo , Coração/crescimento & desenvolvimento , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Mutação de Sentido Incorreto , Contração Miocárdica , Miócitos Cardíacos/metabolismoRESUMO
We investigated cardiac contractility in the ACTC E361G transgenic mouse model of dilated cardiomyopathy (DCM). No differences in cardiac dimensions or systolic function were observed in young mice, whereas young adult mice exhibited only mild diastolic abnormalities. Dobutamine had an inotropic and lusitropic effect on the mouse heart. In papillary muscle at 37°C, dobutamine increased relaxation rates [â¼50% increase of peak rate of force decline normalized to force (dF/dtmin/F), 25% reduction of time to 90% relaxation (t90) in nontransgenic (NTG) mice], but in the ACTC E361G mouse, dF/dtmin/F was increased 20-30%, and t90 was only reduced 10% at 10 Hz. Pressure-volume measurements showed increases in maximum rate of pressure decline and decreases in time constant of left ventricular pressure decay in the ACTC E361G mouse that were 25-30% of the changes in the NTG mouse, consistent with blunting of the lusitropic response. The inotropic effect of dobutamine was also blunted in ACTC E361G mice, and the dobutamine-stimulated increase in cardiac output (CO) was reduced from 2,100 to 900 µl/min. Mice were treated with high doses of ANG II for 4 wk. The chronic stress treatment evoked systolic dysfunction in ACTC E361G mice but not in NTG. There was a significant reduction in rates of pressure increase and decrease, as well as reduced end-systolic pressure and increased volume. Ejection fraction and CO were reduced in the ACTC E361G mouse, indicating DCM. In vitro DCM-causing mutations uncouple the relationship between Ca(2+) sensitivity and troponin I phosphorylation. We conclude that this leads to the observed, reduced response to ß1 agonists and reduced cardiac reserve that predisposes the heart to DCM under conditions of chronic stress.
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Actinas/genética , Agonistas de Receptores Adrenérgicos beta 1/farmacologia , Angiotensina II , Cardiomiopatia Dilatada/fisiopatologia , Cardiotônicos/farmacologia , Dobutamina/farmacologia , Mutação , Contração Miocárdica/efeitos dos fármacos , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular Esquerda/efeitos dos fármacos , Fatores Etários , Animais , Cálcio/metabolismo , Cardiomiopatia Dilatada/induzido quimicamente , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/metabolismo , Modelos Animais de Doenças , Acoplamento Excitação-Contração/efeitos dos fármacos , Predisposição Genética para Doença , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Músculos Papilares/efeitos dos fármacos , Músculos Papilares/metabolismo , Músculos Papilares/fisiopatologia , Fenótipo , Fosforilação , Troponina I/metabolismo , Disfunção Ventricular Esquerda/induzido quimicamente , Disfunção Ventricular Esquerda/metabolismo , Pressão Ventricular/efeitos dos fármacosRESUMO
Phosphorylation of troponin I by protein kinase A (PKA) reduces Ca(2+) sensitivity and increases the rate of Ca(2+) release from troponin C and the rate of relaxation in cardiac muscle. In vitro experiments indicate that mutations that cause dilated cardiomyopathy (DCM) uncouple this modulation, but this has not been demonstrated in an intact contractile system. Using a Ca(2+)-jump protocol, we measured the effect of the DCM-causing mutation ACTC E361G on the equilibrium and kinetic parameters of Ca(2+) regulation of contractility in single transgenic mouse heart myofibrils. We used propranolol treatment of mice to reduce the level of troponin I and myosin binding protein C (MyBP-C) phosphorylation in their hearts before isolating the myofibrils. In nontransgenic mouse myofibrils, the Ca(2+) sensitivity of force was increased, the fast relaxation phase rate constant, kREL, was reduced, and the length of the slow linear phase, tLIN, was increased when the troponin I phosphorylation level was reduced from 1.02 to 0.3 molPi/TnI (EC50 P/unP = 1.8 ± 0.2, p < 0.001). Native myofibrils from ACTC E361G transgenic mice had a 2.4-fold higher Ca(2+) sensitivity than nontransgenic mouse myofibrils. Strikingly, the Ca(2+) sensitivity and relaxation parameters of ACTC E361G myofibrils did not depend on the troponin I phosphorylation level (EC50 P/unP = 0.88 ± 0.17, p = 0.39). Nevertheless, modulation of the Ca(2+) sensitivity of ACTC E361G myofibrils by sarcomere length or EMD57033 was indistinguishable from that of nontransgenic myofibrils. Overall, EC50 measured in different conditions varied over a 7-fold range. The time course of relaxation, as defined by tLIN and kREL, was correlated with EC50 but varied by just 2.7- and 3.3-fold, respectively. Our results confirm that troponin I phosphorylation specifically alters the Ca(2+) sensitivity of isometric tension and the time course of relaxation in cardiac muscle myofibrils. Moreover, the DCM-causing mutation ACTC E361G blunts this phosphorylation-dependent response without affecting other parameters of contraction, including length-dependent activation and the response to EMD57033.
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Actinas/genética , Cálcio/metabolismo , Cardiomiopatia Dilatada/genética , Mutação , Miofibrilas/metabolismo , Troponina I/metabolismo , Animais , Proteínas de Transporte/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Feminino , Masculino , Camundongos , Camundongos Transgênicos , Contração Muscular/efeitos dos fármacos , Miofibrilas/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Propranolol/farmacologia , Quinolinas/farmacologia , Sarcômeros/efeitos dos fármacos , Sarcômeros/metabolismo , Tiadiazinas/farmacologiaRESUMO
The purpose of this study was to investigate whether caveolin-3 (Cav3) regulates localization of ß2-adrenergic receptor (ß2AR) and its cAMP signaling in healthy or failing cardiomyocytes. We co-expressed wildtype Cav3 or its dominant-negative mutant (Cav3DN) together with the Förster resonance energy transfer (FRET)-based cAMP sensor Epac2-camps in adult rat ventricular myocytes (ARVMs). FRET and scanning ion conductance microscopy were used to locally stimulate ß2AR and to measure cytosolic cAMP. Cav3 overexpression increased the number of caveolae and decreased the magnitude of ß2AR-cAMP signal. Conversely, Cav3DN expression resulted in an increased ß2AR-cAMP response without altering the whole-cell L-type calcium current. Following local stimulation of Cav3DN-expressing ARVMs, ß2AR response could only be generated in T-tubules. However, the normally compartmentalized ß2AR-cAMP signal became diffuse, similar to the situation observed in heart failure. Finally, overexpression of Cav3 in failing myocytes led to partial ß2AR redistribution back into the T-tubules. In conclusion, Cav3 plays a crucial role for the localization of ß2AR and compartmentation of ß2AR-cAMP signaling to the T-tubules of healthy ARVMs, and overexpression of Cav3 in failing myocytes can partially restore the disrupted localization of these receptors.
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Caveolina 3/metabolismo , Simulação por Computador , AMP Cíclico/metabolismo , Miócitos Cardíacos/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Transdução de Sinais , Animais , Western Blotting , Caveolina 3/genética , Síndromes Compartimentais/fisiopatologia , Expressão Gênica , Insuficiência Cardíaca/fisiopatologia , RatosRESUMO
OBJECTIVE: Depression is a significant global public health burden, and older adults may be particularly vulnerable to its effects. Among other risk factors, interpersonal conflicts, such as perceived criticism from family members, can increase risk for depressive symptoms in this population. We examined family criticism as a predictor of depressive symptoms and the potential moderating effect of optimism and pessimism. METHODS: One hundred five older adult, primary care patients completed self-report measures of family criticism, optimism and pessimism, and symptoms of depression. We hypothesized that optimism and pessimism would moderate the relationship between family criticism and depressive symptoms. RESULTS: In support of our hypothesis, those with greater optimism and less pessimism reported fewer depressive symptoms associated with family criticism. CONCLUSION: Therapeutic enhancement of optimism and amelioration of pessimism may buffer against depression in patients experiencing familial criticism.
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Conflito Psicológico , Depressão/etiologia , Família/psicologia , Idoso , Depressão/epidemiologia , Feminino , Humanos , Masculino , Atenção Primária à Saúde/estatística & dados numéricos , Escalas de Graduação Psiquiátrica , Inquéritos e QuestionáriosRESUMO
We generated a transgenic mouse model expressing the apical hypertrophic cardiomyopathy-causing mutation ACTC E99K at 50% of total heart actin and compared it with actin from patients carrying the same mutation. The actin mutation caused a higher Ca(2+) sensitivity in reconstituted thin filaments measured by in vitro motility assay (2.3-fold for mice and 1.3-fold for humans) and in skinned papillary muscle. The mutation also abolished the change in Ca(2+) sensitivity normally linked to troponin I phosphorylation. MyBP-C and troponin I phosphorylation levels were the same as controls in transgenic mice and human carrier heart samples. ACTC E99K mice exhibited a high death rate between 28 and 45 days (48% females and 22% males). At 21 weeks, the hearts of the male survivors had enlarged atria, increased interstitial fibrosis, and sarcomere disarray. MRI showed hypertrophy, predominantly at the apex of the heart. End-diastolic volume and end-diastolic pressure were increased, and relaxation rates were reduced compared with nontransgenic littermates. End-systolic pressures and volumes were unaltered. ECG abnormalities were present, and the contractile response to ß-adrenergic stimulation was much reduced. Older mice (29-week-old females and 38-week-old males) developed dilated cardiomyopathy with increased end-systolic volume and continuing increased end-diastolic pressure and slower contraction and relaxation rates. ECG showed atrial flutter and frequent atrial ectopic beats at rest in some ACTC E99K mice. We propose that the ACTC E99K mutation causes higher myofibrillar Ca(2+) sensitivity that is responsible for the sudden cardiac death, apical hypertrophy, and subsequent development of heart failure in humans and mice.
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Actinas/genética , Cardiomegalia/genética , Mutação , Animais , Feminino , Humanos , Masculino , Camundongos , Camundongos TransgênicosRESUMO
There is evidence that psychological treatments for postnatal depression are effective in the short-term; however, whether the effects are enduring over time remains an important empirical question. The aim of this study was to investigate the depressive symptoms and interpersonal functioning of participants in a randomised controlled trial (RCT) of group interpersonal psychotherapy (IPT-G) at 2 years posttreatment. The study also examined long-term trajectories, such as whether participants maintained their recovery status, achieved later recovery, recurrence or persistent symptoms. Approximately 2 years posttreatment, all women in the original RCT (N = 50) were invited to participate in a mailed follow-up. A repeated measures analysis of variance assessed differences between the treatment and control conditions on depression and interpersonal scores across five measurement occasions: baseline, mid-treatment, end of treatment and 3-month and 2-year follow-up. Chi-square tests were used to analyse the percentage of participants in the four recovery categories. Mothers who received IPT-G improved more rapidly in the short-term and were less likely to develop persistent depressive symptoms in the long-term. Fifty seven percent of IPT-G mothers maintained their recovery over the follow-up period. Overall, IPT-G participants were significantly less likely to require follow-up treatment. Limitations include the use of self-report questionnaires to classify recovery. The positive finding that fewer women in the group condition experienced a persistent course of depression highlights its possible enduring effects after treatment discontinuation. Further research is needed to improve our long-term management of postnatal depression for individuals who are vulnerable to a recurrent or chronic trajectory.
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Depressão Pós-Parto/psicologia , Depressão Pós-Parto/terapia , Relações Interpessoais , Mães/psicologia , Educação de Pacientes como Assunto/métodos , Psicoterapia Breve/métodos , Adulto , Feminino , Seguimentos , Humanos , Satisfação do Paciente , Autoimagem , Índice de Gravidade de Doença , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: The stigma of internet surfing is a relatively new area of study arising from the popularity of the internet. The Questionnaire on the Internal Stigma of Internet Surfing-9 (QISIS-9) was developed for the Chinese culture, so its suitability for use in other cultural contexts is uncertain. This paper examines the measurement invariance of the QISIS-9 among Sino-Australian undergraduates to verify the cross-cultural measurement invariance of QISIS-9 and promote cross-cultural (nationality) research regarding the internal stigma of internet surfing. METHODS: The Internal Stigma of Internet Surfing-9 (QISIS-9) was used to assess 200 Chinese undergraduates (50% female, Mage = 19.78) and 204 Australian undergraduates (76% female, Mage = 21.10), respectively. RESULTS: A confirmatory factor analysis (CFA) indicated that the single-factor model of QISIS-9 is acceptable with both Chinese and Australian undergraduates. However, the factor loading of Item 9, to which a reverse score is assigned, is not ideal for both samples. Thus, the item should be deleted. According to a multigroup confirmatory factor analysis (MCFA), QISIS-8, the revised version of QISIS-9, meets the strict measurement invariance among the Chinese and Australian participants. The QISIS-8 demonstrated appropriate internal consistency in the scores for both the Chinese and Australian undergraduates. CONCLUSION: The new QISIS-8 can effectively assess the internal stigma of internet surfing among Chinese and Australian undergraduates, and it provides a frame of reference for further cross-cultural (border) comparisons.
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INTRODUCTION: Vaporised nicotine products (VNPs) may be useful smoking cessation aids for people in alcohol and other drug (AOD) treatment, a population with high tobacco-related morbidity and mortality rates. This qualitative study aimed to examine the barriers and facilitators of using VNPs as part of a clinical trial to reduce or quit smoking among people in AOD treatment. METHODS: Thirteen people in AOD treatment who were participating in a trial of VNPs for smoking cessation (QuitENDs) completed a brief semi-structured interview examining experiences of using VNPs to reduce or quit smoking. Transcribed data was analysed using the iterative categorisation framework. RESULTS: Many participants expressed the benefit of having a smoking cessation aid that addressed nicotine cravings and the behavioural hand-to-mouth action to help them reduce or quit smoking. Although many participants reported that VNPs were easy to use, some found maintaining the device to be challenging. Some participants described Australian regulations limiting use of VNPs as reducing their desire to use the device as a cessation aid. Many participants attempting to reduce or quit tobacco and cannabis simultaneously stated that VNPs alone were insufficient to help them reduce or quit tobacco. CONCLUSIONS: VNPs hold significant promise as smoking cessation aids among people in AOD treatment because of their unique ability to satisfy both nicotine cravings and behavioural habits. However, multiple barriers, such as accessibility, maintenance, and the challenges of reducing other substance use simultaneously also need to be addressed for optimal engagement in clinical trials with VNPs to quit smoking.
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Sistemas Eletrônicos de Liberação de Nicotina , Abandono do Hábito de Fumar , Transtornos Relacionados ao Uso de Substâncias , Austrália , Humanos , Nicotina/uso terapêutico , Dispositivos para o Abandono do Uso de TabacoRESUMO
The Cambridge Face Memory Test (CFMT, Duchaine & Nakayama, 2006) provides a validated format for testing novel face learning and has been a crucial instrument in the diagnosis of developmental prosopagnosia. Yet, some individuals who report everyday face recognition symptoms consistent with prosopagnosia, and are impaired on famous face tasks, perform normally on the CFMT. Possible reasons include measurement error, CFMT assessment of memory only at short delays, and a face set whose ethnicity is matched to only some Caucasian groups. We develop the "CFMT-Australian" (CFMT-Aus), which complements the CFMT-original by using ethnicity better matched to a different European subpopulation. Results confirm reliability (.88) and validity (convergent, divergent using cars, inversion effects). We show that face ethnicity within a race has subtle but clear effects on face processing even in normal participants (includes cross-over interaction for face ethnicity by perceiver country of origin in distinctiveness ratings). We show that CFMT-Aus clarifies diagnosis of prosopagnosia in 6 previously ambiguous cases. In 3 cases, this appears due to the better ethnic match to prosopagnosics. We also show that face memory at short (<3-min), 20-min, and 24-hr delays taps overlapping processes in normal participants. There is some suggestion that a form of prosopagnosia may exist that is long delay only and/or reflects failure to benefit from face repetition.
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Etnicidade/psicologia , Face , Expressão Facial , Testes Neuropsicológicos , Prosopagnosia/psicologia , Reconhecimento Psicológico/fisiologia , Adolescente , Adulto , Austrália , Automóveis , Estudos Cross-Over , Interpretação Estatística de Dados , Feminino , Humanos , Israel , Masculino , Estimulação Luminosa , Prosopagnosia/diagnóstico , Psicometria , Desempenho Psicomotor/fisiologia , Valores de Referência , Reprodutibilidade dos Testes , Fatores Sexuais , Software , População Branca , Adulto JovemRESUMO
Competitive cyclists typically sprint out of the saddle and alternately lean their bikes from side to side, away from the downstroke pedal. Yet, there is no direct evidence as to whether leaning the bicycle or conversely, attempting to minimize lean, affects maximal power output during sprint cycling. Here, we modified a cycling ergometer so that it can lean from side to side but can also be locked to prevent lean. This modified ergometer made it possible to compare maximal 1-s crank power during non-seated, sprint cycling under three different conditions: locked (no lean), ad libitum lean, and minimal lean. We found that leaning the ergometer ad libitum did not enhance maximal 1-s crank power compared to the locked condition. However, trying to minimize ergometer lean decreased maximal 1-s crank power by an average of 5% compared to leaning ad libitum. IMU-derived measures of ergometer lean provided evidence that subjects leaned the ergometer away from the downstroke pedal during the ad-lib condition, as in overground cycling. This finding suggests that our ergometer provides a suitable emulation of bicycle-lean dynamics. Overall, we find that leaning a cycle ergometer ad libitum does not enhance maximal power output, but conversely, trying to minimize lean impairs maximal power output.
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Ciclismo , Ergometria , Teste de Esforço , HumanosRESUMO
Instantaneous crank power does not equal total joint power if a rider's centre of mass (CoM) gains and loses mechanical energy. Thus, estimating CoM motion and the associated energy changes can provide valuable information about the mechanics of cycling. To date, an accurate and precise method for tracking CoM motion during outdoor cycling has not been validated. PURPOSE: To assess the suitability of using data from a single inertial measurement unit (IMU) secured to the lower back of the rider for estimating CoM motion during non-seated cycling by comparing vertical displacement derived from the IMU to that of an attached marker cluster and to a full-body kinematic estimate of vertical CoM displacement. METHODS: IMU and motion capture data were collected synchronously for 10 s while participants (n = 7) cycled on an ergometer in a non-seated posture at six combinations of power output and cadence. A limits-of-agreement analysis, corrected for repeated measures, was performed on the range of vertical displacement between the IMU and the two other measures. A total of 303 crank cycles were analysed. RESULTS: There was excellent agreement between the vertical displacement derived from the IMU and the attached marker cluster (accuracy = 1.6 mm, precision = 3.5 mm). Vertical displacement derived from the IMU systematically overestimated the kinematic estimate of whole-body CoM-with errors increasing linearly with displacement. CONCLUSION: We interpret these findings as evidence that a single IMU secured to the lower back can provide a suitable approach for deriving a cyclist's CoM displacement when they ride out of the saddle, but only if the linearly increasing overestimation is accounted for.
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Movimento , Postura , Fenômenos Biomecânicos , Ergometria , Humanos , Movimento (Física)RESUMO
This study is a randomised controlled trial comparing outcomes from an 8-week Interpersonal Psychotherapy group (IPT-G) for postnatal depression with 'treatment as usual' (TAU), conducted in a routine community setting in the Australian Capital Territory (ACT). Eligible women were recruited and randomly assigned to either IPT-G or TAU conditions. This study compared outcomes on such variables as depressive symptoms, marital adjustment, social support and mother-infant bond at baseline, mid-treatment, end-of-treatment and 3 months follow-up. Participants were also independently assessed using the Hamilton Depression Rating Scale (HAM-D). 50 women completed baseline assessments and were included in the analysis. Comparisons of treatment conditions showed that by end of treatment both the TAU and IPT-G groups significantly improved in terms of mean depression scores, however, the IPT-G women improved significantly more and had continued improvements at 3 months post therapy. Furthermore, women who received IPT-G displayed significant improvement in terms of marital functioning and perceptions of the mother-infant relationship compared to TAU participants. These findings highlight the potential benefits of an interpersonally based treatment, which not only improves outcomes for the mother but also potentially for the couple and the infant when compared to usual care.
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Depressão Pós-Parto/psicologia , Depressão Pós-Parto/terapia , Relações Interpessoais , Psicoterapia/métodos , Adulto , Depressão Pós-Parto/diagnóstico , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Humanos , Recém-Nascido , Índice de Gravidade de Doença , Inquéritos e Questionários , Resultado do TratamentoRESUMO
This study examined the utility of the newly developed Adolescent Friendship Attachment Scale (AFAS) for the prediction of adolescent psychological health and school attitude. High school students (266 males, 229 females) were recruited from private and public schools in the Australian Capital Territory with ages of participants ranging from 13 to 19 years. Self-report measures of depression, self-esteem, self-competence and school attitude were administered in addition to the AFAS and a short-form of the Inventory of Parental and Peer Attachment (IPPA). Regression analyses revealed that the AFAS Anxious and Avoidant scales added to the prediction of depression, self-esteem, self-competence, and school attitude beyond the contribution of the IPPA. It is concluded that the AFAS taps aspects of adolescent attachment relationships not assessed by the IPPA and provides a useful contribution to research and practice in the area of adolescent psycho-social adjustment.
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Adaptação Psicológica , Amigos/psicologia , Apego ao Objeto , Grupo Associado , Psicologia do Adolescente , Identificação Social , Logro , Adolescente , Atitude , Feminino , Humanos , Masculino , Inventário de Personalidade/estatística & dados numéricos , Psicometria , Reprodutibilidade dos Testes , Autoimagem , Ajustamento SocialRESUMO
When cyclists ride off the saddle, their center of mass (CoM) appears to go through a rhythmic vertical oscillation during each crank cycle. Just like in walking and running, the pattern of CoM movement may have a significant effect on the mechanical power that needs to be generated and dissipated by muscle. PURPOSE: To date, neither the CoM movement strategies during nonseated cycling nor the limb mechanics that allow this phenomenon to occur have been quantified. METHODS: Here we estimate how much power can be contributed by a rider's CoM at each instant during the crank cycle by combining a kinematic and kinetic approach to measure CoM movement and joint powers of 15 participants riding in a nonseated posture at three individualized power outputs (10%, 30%, and 50% of peak maximal power) and two different cadences (70 and 120 rpm). RESULTS: The peak-to-peak amplitude of vertical CoM displacement increased significantly with power output and with decreasing cadence. Accordingly, the greatest peak-to-peak amplitude of CoM displacement (0.06 ± 0.01 m) and change in total mechanical energy (0.54 ± 0.12 J·kg) occurred under the combination of high-power output and low cadence. At the same combination of high-power output and low cadence, we found that the peak rate of CoM energy loss (3.87 ± 0.93 W·kg) was equal to 18% of the peak crank power. CONCLUSION: Consequently, it appears that for a given power output, changes in CoM energy contribute to peak instantaneous power output at the crank, thus reducing the required muscular contribution. These findings suggest that the rise and fall of a rider's CoM acts as a mechanical amplifier during nonseated cycling, which has important implications for both rider and bicycle performance.
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Ciclismo/fisiologia , Fenômenos Biomecânicos/fisiologia , Movimento/fisiologia , Músculo Esquelético/fisiologia , Posição Ortostática , Adulto , Desempenho Atlético/fisiologia , Articulação do Quadril/fisiologia , Humanos , MasculinoRESUMO
Cyclists frequently use a nonseated posture when accelerating, climbing steep hills, and sprinting; yet, the biomechanical difference between seated and nonseated cycling remains unclear. PURPOSE: This study aimed to test the effects of posture (seated and nonseated) and cadence (70 and 120 rpm) on joint power contributions, effective mechanical advantage, and muscle activations within the leg during very-high-power output cycling. METHODS: Fifteen male participants rode on an instrumented ergometer at 50% of their individualized instantaneous maximal power (10.74 ± 1.99 W·kg; above the reported threshold for seated to nonseated transition) in different postures (seated and nonseated) and at different cadences (70 and 120 rpm) while leg muscle activity, full-body motion capture, and crank radial and tangential forces were recorded. A scaled, full-body model was used to solve inverse kinematics and inverse dynamics to determine joint displacements and net joint moments. Statistical comparisons were made using a two-way repeated-measures ANOVA (posture-cadence). RESULTS: There were significant main effects of posture and cadence on joint power contributions. A key finding was that the nonseated posture increased negative power at the knee, with an associated significant decrease of net power at the knee. The contribution of knee power decreased by 15% at both 70 and 120 rpm (~0.8 W·kg) when nonseated compared with seated. Subsequently, hip power and ankle power contributions were significantly higher when nonseated compared with seated at both cadences. In both postures, knee power was 9% lower at 120 rpm compared with 70 rpm (~0.4 W·kg). CONCLUSION: These results evidenced that the contribution of knee joint power to leg power was reduced by switching from a seated to nonseated posture during very-high-power output cycling; however, the size of the reduction is cadence dependent.
Assuntos
Tornozelo/fisiologia , Ciclismo/fisiologia , Quadril/fisiologia , Joelho/fisiologia , Postura , Adulto , Fenômenos Biomecânicos , Eletromiografia , Teste de Esforço , Humanos , Masculino , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Estudos de Tempo e Movimento , Adulto JovemRESUMO
INTRODUCTION AND AIMS: Electronic cigarettes (e-cigarettes) are becoming popular and may be a potential harm reduction and quit smoking aid for people who use other drugs. Data on e-cigarette use and perceptions among people who use drugs is limited. The current study examines tobacco smoking status, use and attitudes towards e-cigarettes among people in drug and alcohol treatment. DESIGN AND METHODS: Data were collected through a standardised Patient Experience Tracking System device installed in the waiting room of six drug and alcohol clinical service programs located within one area health service in New South Wales, Australia during April to June 2017. Participants were clients of participating services aged 18 years and older. RESULTS: Five hundred and eleven participants completed the survey, 85% were current smokers, 9% were ex-smokers and 6% were non-smokers. Over half of all participants (53%) had tried e-cigarettes in their lifetime, 26% reported current use and 77% of those were using them with nicotine. Just less than half of all participants believed that e-cigarettes were helpful for quitting or cutting down smoking tobacco cigarettes (48%). More than half of all respondents (59%) believed that tobacco cigarettes were more harmful than e-cigarettes (59%) and believed that e-cigarettes were an acceptable quit smoking aid for patients of drug and alcohol services (64%). DISCUSSION AND CONCLUSIONS: Most participants were current tobacco smokers and had tried an e-cigarette though a minority were currently using e-cigarettes. Participant attitudes were favourable towards the use of e-cigarettes as quit smoking aids.
Assuntos
Consumo de Bebidas Alcoólicas/psicologia , Usuários de Drogas/psicologia , Abandono do Hábito de Fumar/psicologia , Vaping/psicologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Consumo de Bebidas Alcoólicas/epidemiologia , Austrália , Estudos Transversais , Sistemas Eletrônicos de Liberação de Nicotina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fumantes/psicologia , Abandono do Hábito de Fumar/estatística & dados numéricos , Inquéritos e QuestionáriosRESUMO
We describe an articular talar dome fracture treated with the use of an arthroscopically assisted placement of a transfibular Acutrak screw (Accumed, Hillsboro, OR). This minimally invasive technique can be used to avoid the large incision used in the traditional open reduction and internal fixation of these fractures. Accurate reduction and stable fixation of fractures of the articular surface of the talus is a must, and this technique allows this while avoiding the morbidity of the open approach.