A biomechanical investigation of the effects of pregnancy on spinal motion and rising to stand from a chair

During pregnancy the female body must accommodate the enlarging gravid uterus and increased mass. Therefore the maternal musculoskeletal system is required to adapt in both morphology and functional workload. After childbirth there is a rapid change in both mass and dimensions, requiring further adaptations. The objectives of the study were to investigate seated and standing upper body posture, the kinematics of seated and standing trunk motion, and the three dimensional kinematics and kinetics during rising to stand from a chair, as pregnancy progressed and in the early post-birth period. Nine maternal subjects (aged 28 to 40 years) were tested at less than 16 weeks, 24 weeks, 30 weeks, 38 weeks gestation and at 8 weeks postbirth. The subjects, fitted with 37 retroreflective markers, were filmed during upright sitting, quiet standing, and four trials each of maximum seated and standing trunk forward flexion, side to side flexion and during maximum seated axial rotation. Three trials each of constrained and free rising to stand from a height adjustable stool and with each foot placed on a forceplate were also recorded. An eight-camera motion analysis system was used to record movements of the body segments and synchronised force plate variables in three dimensions. Motion of the ankle, knee and hip joints, pelvic, thoracic and head segments and the thoracolumbar and cervicothoracic spines and shoulder joints were investigated. Twelve nulliparous subjects (aged 21 to 35 years) were used as controls to provide standard descriptive data and to investigate the consistency of the selected biomechanical variables with repeated testing. A repeated measures ANOVA was used to investigate the possibility of linear and quadratic trends showing systematic changes within the maternal group, over the four test sessions during pregnancy for each variable. Two tailed Student t-tests were used to compare the maternal postbirth variable results with the control group. There was no significant effect of pregnancy on the upper body posture during upright sitting and quiet standing. Postbirth, the pelvic segment had a smaller anterior orientation and the thoracolumbar spine was less extended, indicating a flatter spinal curve. The maternal subjects were similar to the control subjects in early pregnancy and postbirth for trunk segment motions during seated and standing forward flexion and side to side flexion and seated axial rotation. Strategies, such as increasing the width of the base of support and reducing obstruction to movements from other body parts, were used in late pregnancy in attempts to minimise the effects of increased trunk mass and circumference. For seated and standing side to side flexion, the strategies were successful and no significant decreases in range of motion were seen. For seated and standing forward flexion and seated axial rotation, motion of the thoracic segment and the thoracolumbar spine were significantly reduced, although movement of the pelvis was less affected. In early pregnancy and postbirth the kinematics and kinetics of the lower limbs and upper body segment kinematics during constrained and free rising were generally similar to the control subjects. As pregnancy progressed there were increases in mass and dimensions of body segments. The effect of increased mass was seen in increased ground reaction forces and sagittal plane lower limb joint external moments. An increased base of support width was found in association with an increased lateral ground reaction force and ankle inversion moment from each foot, which would move the body centre of mass medially. There was little change in the three dimensional kinematics of the thoracolumbar and cervicothoracic spine, although the contribution of the upper body segments differed for each rise condition. There were also few significant changes in the displacement of the ankle, knee and hip, and the angular velocity of ankle and knee joints. The maternal subjects were thus able to flex the upper body forward, raise the body and maintain stability as pregnancy progressed, regardless of whether the rise to stand was performed in a natural manner or under constrained conditions. The overall results show that, contrary to expectations as pregnancy progressed, maternal subjects minimised propulsion rather than increasing it to overcome the increased mass and possibly limited trunk flexion. A fear of postural instability may have made the subjects more cautious and as they were able to adequately flex the trunk forward, propulsion was minimised in favour of maintaining upright terminal balance

Editorial for special issue Ageing, body and society: Key themes, critical perspectives

Over the last two decades significant theoretical, methodological and empirical developments have explored the social, biological and cultural dimensions of our bodies as we grow older. An earlier concern within ageing studies that a focus on the bodies of older people represented a return to biological determinism and an overly medical approach has been replaced by a realisation how a focus on ageing bodies offers a novel lens to examine a range of existing sociological and theoretical concerns. These include the nature of the body, self and ageing; social identities and social inequalities; lived experiences and everyday life; the role of materiality and consumption in the cultural constitution of age; health and illness; and ageing across the full lifecourse from midlife to deep old age. It is over twenty years since Peter Őberg published his seminal article in Ageing & Society on the absent body in gerontology (Öberg, 1996). It is therefore timely to bring together established and emergent researchers to review the wealth of work in this area, and to take forward key debates, enhance current and emergent theoretical perspectives, and disseminate empirical research in ‘ageing, body and society’. In particular, this special issue aims to highlight and explore interconnections between the corporeality of ageing bodies and the socio-cultural context in which we live. The special issue has built upon the international networks and focus of the British Sociological Association (BSA) Ageing, Body and Society study group1 for which the co-editors Dr. Wendy Martin and Professor Julia Twigg have been co-convenors since 2007. Through international symposia and an annual one day conference, the study group has brought together international academics and researchers whose work focuses on ageing, bodies and embodiment, exploring and debating different theoretical perspectives, methodological approaches and empirical findings

Three-dimensional analysis of a lofted instep kick by male and female footballers

There is a paucity of data describing the lofted instep kick and little information on the kinematic differences between male and female footballers. This study provides a preliminary investigation into the differences in motion patterns between the sexes. A four-camera motion analysis system videoed 13 amateur footballers (7 female and 6 male) attempting a standardised task that represented a lofted instep kick of approximately 35 m. Footballers performed 20 kicks, with the three trials categorised closest to the standardised distance retained for statistical analysis. Three-dimensional motion patterns for kicks of 35 m illustrated that female footballers produced greater fluctuation in movement patterns for pelvic, hip joint and thoracolumbar spine motion in the frontal plane; thorax and hip joint transverse rotation; and ankle dorsiflexion/plantarflexion motion. Peak hip extension (P = 0.018), impact hip abduction (P = 0.032), impact ankle plantar flexion (P = 0.030) and resultant ball velocity (P = 0.004) differed significantly between sexes. Principle component analysis highlighted associations between kinematic variables related to ball velocity and sex including a reduced hip abduction and increased internal rotation approaching impact, and greater peak knee flexion, respectively. In summary, increased variation in direction of segment motion, increased backswing and formation of a tension arc by females compared to males, may be related to anthropometric, strength and muscle activation differences. Specifically, this exploratory study indicates future research would benefit from exploring trunk, pelvis and hip kinematics and kinetics, and whether training the trunk, pelvis and hip musculature assists female footballers.Published versio

The Visual Matrix method in a study of death and dying: Methodological reflections

The Visual Matrix method is designed to elicit imagistic and associative contributions established collectively amongst participants in a group setting. In this article, a hard to-reach area of experience - death and dying - illustrates the production of shared cultural images beyond individual experience. Our dual purpose was to assess the suitability of the method for this challenging topic, and to understand the ways in which death figured in the imagination of the participants. Three theorists, Wilfred Bion, Alfred Lorenzer and Gilles Deleuze, enable us to theorise psychosocial processes of symbolisation beyond cognition

Tibia and rearfoot motion and ground reaction forces in subjects with patellofemoral pain syndrome during walking

Abnormal subtalar joint function and the consequent rotation of the tibia during walking are thought to contribute to patellofemoral pain syndrome (PFPS). The purpose of this study was to measure rearfoot and tibia motion, and the ground reaction force (GRF) during the stance phase of walking in subjects with PFPS and compare them to healthy subjects. A four camera motion analysis system with a single force plate was used to investigate rearfoot motion relative to the tibia in three planes, the tibial transverse plane rotation and the GRF during the stance phase of walking in 13 female subjects diagnosed with PFPS and 14 healthy females. Analysis showed significantly delayed peak rearfoot eversion (p=0.02), and earlier occurrence of peak dorsiflexion (p=0.02) for the PFPS group. Furthermore, significantly lower peak medial GRF (p=0.03), minimum vertical GRF trough (p=0.02) and the second vertical GRF peak (p=0.01) were found in the PFPS group. Tibial transverse rotation was not shown to be different in PFPS subjects. However, there was prolonged rearfoot eversion during the stance phase of walking. The earlier appearance of rearfoot dorsiflexion as well as the lower GRFs indicate altered propulsive function of the foot during supination

An evaluation of the rearfoot posture in individuals with patellofemoral pain syndrome

Structural abnormalities of the foot may cause abnormal subtalar joint compensatory motion in order to attain normal function of the lower extremity during gait although studies have not been conclusive. Current conflict in the literature may be related to the differing measures focused on the varying protocols and also the absence of a control group in some studies. This study investigated the rearfoot posture including Subtalar Joint Neutral Position (STJN) and Relaxed Calcaneal Standing (RCS) measurements in patellofemoral pain syndrome (PFPS) and healthy subjects. The angle of STJN during non-weight bearing position and the two dimensional (2D) rearfoot RCS posture was measured using a goniometer in 14 healthy females and 13 females with PFPS. The RCS posture was also measured three dimensionally (3D) by attaching external markers to a tibia shell and the calcaneus and videoing with a four-camera three-dimensional motion analysis system. A one way ANOVA was used to assess the differences between the groups. The 2D and 3D RCS were significantly different between the groups (p ≤ 0.001) with mean -0.23° ± 1.35° , 2.52° ± 3.11° for the control group and 2.35° ± 1.4°, 7.02° ± 3.33° for the clinical group respectively. STJN showed a slight rearfoot varus (although significant p = 0.04) in PFPS (-2.20° ± 1.51° ) compared to the control group (-1.00° ± 1.36°). Negative values indicated inversion and positive values indicated eversion. The 2D and 3D RCS showed a significantly more everted posture of the rearfoot for the PFPS group. Subtalar joint varus may contribute to the increased eversion during relaxed standing in the PFPS group. Rearfoot measurements may be an important addition to other clinical measurements taken to explore the underlying aetiology of subjects with PFPS

Relationship between static posture and rearfoot motion during walking in patellofemoral pain syndrome: Effect of a reference posture for gait analysis

The reference posture used in angular motion calculations may play an important role in the relationship found between static posture and rearfoot motion in the frontal plane in a clinical population such as patients with patellofemoral pain syndrome. This study examined the relationship between rearfoot inversion and eversion during the stance phase of walking and the static relaxed standing measurement in women (aged 18 years and older) with patellofemoral pain syndrome and controls and examined the influence of the reference posture used when calculating dynamic motion. Two reference postures were investigated: vertical alignment between the rearfoot and the lower leg and relaxed calcaneal standing. When using the latter reference posture, a significant correlation was found between the static relaxed standing measurement and peak eversion in controls only. When using the vertical alignment reference posture, significant correlation was found only in the patellofemoral pain syndrome group for peak eversion and inversion. The positive relationship found in the patellofemoral pain syndrome group between dynamic angular measures, based on a neutral reference posture, and static relaxed standing indicated that for subjects with patellofemoral pain syndrome, the clinical rearfoot measurement of relaxed standing can be used to explain the pattern of rearfoot motion during walking

An investigation of a reference position used in determining rearfoot kinematics for both healthy and patellofemoral pain syndrome individuals

The choice of a reference posture is important when investigating rearfoot motion in clinical populations. The reference posture used may affect the magnitude of the peak angles and therefore may not enable comparison of the rearfoot kinematics across different populations. This study examined the relationship between the rearfoot frontal plane pattern of motion and three reference postures during the stance phase of walking in healthy and patellofemoral pain syndrome (PFPS) subjects. The three reference postures investigated were: Relaxed Standing posture, subtalar joint neutral position (STJN) and when the calcaneus and the lower leg were vertically aligned (Vertical Alignment). The rearfoot inversion/eversion during the stance phase was measured in 14 healthy subjects and 13 subjects with diagnosed PFPS using three dimensional motion analysis with the three different reference postures. The graphs of rearfoot inversion/eversion motion were overlaid with the angle at the rearfoot in the static posture and any intersection between the static angle and rearfoot motion was noted. An ANOVA showed significant differences in static posture between the groups for Relaxed Standing (p = 0.01), and STJN (p = 0.02). For both groups, with Relaxed Standing as a reference posture, the mean rearfoot pattern of motion did not intersect the Relaxed Standing static angle during the stance phase. The use of Vertical Alignment reference posture, however, showed an intersection of this reference posture through the rearfoot pattern of motion. The use of the Vertical Alignment reference posture also generated a typical rearfoot motion pattern for both groups and therefore it may be an appropriate reference posture for both healthy and PFPS individuals