no abstract provided / Thesis / Master of Science (MSc)

The purpose of this study was to determine the effects of short-term (14d) unilateral leg immobilization using a simple knee brace (60° flexion)/crutchmediated model on muscle function and morphology in men (M, N=13) and women (W, N=14). Isometric and isokinetic (concentric SLOW, 0.52 rad•s-1 and FAST, 5.24 rad•s-1) knee extensor peak torque was determined at three time points (PRE, DAY -2, and DAY -14). At the same time points, magnetic resonance imaging was used to measure the cross-sectional area of the quadriceps femoris and DEXA scanning was used to calculate leg lean mass. Muscle biopsies were taken from vastus lateralis at PRE and DAY-14 for myosin ATPase and myosin heavy chain analysh Women showed greater decreases (PRE vs. DAY-14) compared to men in specific strength (N•cm-2) for isometric (M=3.1±13.3, W=17.1±15.9%; p= 0.055, [mean±SD]) and concentric SLOW (M=4.7±11.3, W=16.6±18.4%; p<0.05) contractions. There were no immobilization-induced sex-specific differences in the decrease in quadriceps femoris cross-sectional area (M=5.7±5.0, W=5.9±:5.2%) or leg lean mass (M=3.7±4.2, W=2.7±2.8%). There were no fiber type transformations, and the decrease in Type I (M=4.8±5.0, W=5.9±3.4%), IIa (M=7.9±9.9, W=8.8±8.0%) and Ilx (M=10.7±10.8, W=10.8±12.1 %) fiber areas was similar between sexes. These findings indicate that immobilization-indt: ced loss of knee extensor muscle strength is greater in women compared tc men in spite of a similar extent of atrophy at the myofiber and whole muscle levels after only 14d of unilateral leg immobilization. Furthermore, we have described an effective and safe method of knee immobilization that results in significant reductions in quadriceps muscle strength and fiber size. / Thesis / Master of Science (MS)

In 2021, over three and a half million women entered the postpartum period in the United States [1]. Despite their prevalence, postpartum health is a largely overlooked area. After delivery, 25% of women within this population experience lumbopelvic or pelvic pain during the typical postpartum period [3], up to 8 weeks post-delivery, and research has found these women may continue to experience pain years after delivery [4]. Persistent pelvic region pain in postpartum women may result in lower limb load asymmetry. Additionally, external loading from carrying a child may alter the degree of asymmetric loading that exists in the lower limbs. Therefore, the first purpose of this study was to investigate the effect of daily tasks on lower extremity load symmetry using metrics that have successfully identified load asymmetry in other populations. Load symmetry was found to differ between task, with the largest asymmetry occurring between limbs during the sit-to-stand task for the peak impact force (PIF = 9.08% symmetry) and during the stair descent task for the average loading rate (ALR = 15.43% symmetry). The increase in asymmetry during these tasks may be attributed to increased muscle activation and force production. The second purpose of this study was to investigate the effect of an external child load on lower extremity load asymmetry during a 14-meter level walking task. A significant increase was found between the no load and both child load conditions for PIF and ALR (p <0.001 for both metrics). No statistically significant differences in symmetry were found between carrying the child centrally in a carrier and carrying on one side of the body without a carrier. The lack of difference in asymmetry during child carrying conditions may indicate mothers naturally compensate for the external child load as both ALR and PIF values increased during these conditions, but asymmetry was not impacted. Our results indicate the need to continue to examine different carrying conditions in postpartum women to better understand risk factors for pain or injury and provide evidence-based recommendations for postpartum activity progression. / Master of Science / In 2021, over three and a half million women entered the postpartum period in the United States [1]. Despite their prevalence, postpartum health is a largely overlooked area and 25% of women experience low back or pelvic pain past the typical postpartum period of 8 weeks post delivery [3]. Research has found women may continue to experience this pain years after delivery and result from the lower limbs being loaded unequally. The extra weight from carrying a child may also impact the amount of unequal loading placed onto the lower limbs. The first purpose of this study was to investigate the effect of daily tasks on load symmetry in the lower limbs using measures that have successfully identified unequal load distribution in non-pregnant individuals. Load symmetry was found to differ between task, with the largest asymmetry occurring between limbs during the sit-to-stand task for the force applied to lower limbs during initial contact of the feet and during the stair descent task for the rate that force was applied to lower limbs. The second purpose of this study was to investigate the effect of an external child load on lower extremity load asymmetry during a 14-meter level walking task. A significant increase was found between the no load and both baby load conditions for force applied during initial contact of the feet and rate this force was applied. No difference was found between child carrying external loading condition when evaluating asymmetry. Our results indicate the need to continue to investigate the unique loading patterns of postpartum women to better understand the specific risk factors for pain or injury development within this population.

Yes / Phantom Limb pain (PLP) affects up to 85% of all patients following an amputation, causing debilitating effects on their quality of life. Mirror Therapy (MT) has been reported to have potential success for the alleviation of PLP. Current understanding of PLP and the efficacy of MT for its alleviation are still unclear, therefore guidelines for treatment protocols are lacking. This literature review assesses the current best evidence for using MT to alleviate PLP of patients with amputation. Method: The authors systematically searched the academic databases Medline, Amed, CINAHL and Google Scholar, using key search terms with inclusion and exclusion criteria to identify relevant articles on the use of MT in populations of patients suffering PLP after unilateral limb amputation. Findings: Seven primary papers were identified and appraised. All the articles reported significant PLP alleviation after using MT with a trend for achieving phantom limb movement (PLM) prior to pain relief. Conclusions: Mirror Therapy is a promising intervention for PLP. Regular MT sessions are required to maintain treatment effect. Causes of PLP and pathways to its alleviation may be multifactorial; therefore further well-conducted RCTs are required to identify best practice.

This thesis investigates coordination of the lower limb joints within the limb during walking. The researcher was motivated by her clinical experience as a paediatric physiotherapist. She observed that the pattern of lower limb coordination differed between normal children and those with cerebral palsy. Many of the currently used interventions did not appear to influence this patterning. As a precursor to evaluating the effectiveness of treatments in modifying coordination, a tool to measure coordination was required. The researcher initially investigated qualitative and then quantitative methods of measuring within limb coordination. A technique was developed that used relative angular velocity of two joints to determine when joints were in-phase, antiphasic or in stasis. The phasic parameters of hip/knee, knee/ankle and hip/ankle joints coordination were quantified. There were some significant differences between normal children and children with cerebral palsy. Asymmetry of these phasic parameters was identified, with children with cerebral palsy being more asymmetrical than normal children. The clinical utility of this technique was tested by comparing 2 groups of children before and after 2 surgical procedures. This showed some significant differences in phasic parameters between pre and post-operative data for one procedure. Low samples sizes mean that further work is required to confirm these findings. Data from this work has been used to calculate sample sizes to give an a priori power of 0.8 and further research is proposed and potential applications discussed. It is hoped that this technique will raise awareness of abnormal intra-limb coordination and allow therapists to identify key interactions between joints that need to be facilitated during walking training.

The development of the vertebrate limb is a progressive process characterized by initial induction and patterning, concomitant growth and morphogenesis, and subsequent cell differentiation and tissue formation. Many of these processes are regulated by specific signaling centers and the environment they create. Through both classical approaches and recent molecular studies, we are beginning to understand the roles of these signaling events during limb development. However, several questions still remain and need to be further addressed. In this dissertation, I first examine how signaling molecules regulate the proximal-distal (PD) patterning of the limb. We demonstrate that early limb mesenchyme is initially maintained in a state capable of generating all limb segments by a combination of proximal and distal signals. As the limb grows, the proximal limb is established by exposure to flank-derived signal(s), whereas the distal segments are determined by distal signals when cells grow beyond the proximal influence. Thus, these results support the “two signal model” and contradict the classical view of PD patterning by a clock-based system that was postulated in the “progress zone model”. In the second part of this work, I focus on a later developmental event and study the cell- and non-cell-autonomous function of Sonic hedgehog (Shh) during limb muscle formation. Muscle progenitor cells migrate from the lateral somites into the developing limb, where they undergo patterning and differentiation in response to local signals. We find that Shh patterns limb musculature non-cell-autonomously, acting through adjacent non-muscle mesenchyme. However, Shh functions cell-autonomously to maintain cell survival in the dermomyotome and promote slow muscle differentiation. Finally, Shh signaling is required cell-autonomously to maintain Net1 expression, which in turn regulates directional muscle cell migration in the distal limb. The dissertation ends with three appendices, describing separate studies: first, mechanisms of limb loss in snakes, second, the role of Hippo signaling in limb development, and lastly a collaborative work with Dr. Jérôme Gros on limb morphogenesis. Taken together, this dissertation provides a glimpse into the diverse roles of signaling pathways during various stages of vertebrate limb development.

Purpose: Several studies have examined intralimb coordination between the shoulder and elbow joints during target-oriented movements. These studies have observed consistent patterns in coordination despite changes in movement variables such as speed, direction, and inertia. Researchers used intersegmental dynamics to quantitatively analyze these patterns between shoulder and elbow joints while systematically changing values of these movement variables. Some studies have examined central nervous system adaptations to inertial changes at the elbow and entire arm during a movement, but none have examined inertial changes to the upper limb. Methods: Five male and five female participants aged 27 to 39 years (mean age = 33 ± 4.3 standard deviation) performed a maximal speed, point-to-point, reversal hand movement in the sagittal plane with and without a 2.2 kg. weight attached to their dominant, right upper arm. To determine the effects of the added mass, dependent t-tests were performed on elbow and shoulder peak muscular torques generated during the reversal region of the movement. Results: A significant increase in shoulder joint torque (p < 0.05), a significant increase in movement time (p < 0.05) and a non-significant decrease in elbow muscular torque (p = 0.1074) was shown to achieve the movement objective with the added weight. Conclusions: While future studies may result in more conclusive findings, this study showed a pattern of increased shoulder torque and decreased elbow torque due to the added inertia. Larger shoulder torque was needed to overcome the added inertia and move at high speed. As a result of the higher shoulder force, interaction torque at the elbow increased, and a reduction in elbow torque was needed to control the hand path and accurately hit the targets. This pattern supports Bernstein’s proposal that passively arising phenomena (i.e., interaction torque) is exploited during multi-segment movement.

Title: The effect of exercise with blood flow restriction on the development of muscle strength Objectives: The aim of this work was to assess the magnitude of the effect of exercise with blood flow restriction on the development of muscle strength on the basis of a systematic research and to determine the main factors that moderate this increase. Methods: Primary sources were searched in the scientific databases Academic Search Ultimate, Web of Science and Taylor and Francis. Individual training interventions were found in the included studies. Based on the training interventions, possible moderating factors of the magnitude of the effect on the development of muscular strength of the upper or lower limbs were defined. From the results of the studies, the effect size values of Cohen's d and Hedge's g were calculated. The influence of concrete parameters of application of the vascular occlusion and blood flow restriction exercise on the magnitude of the effect was evaluated on the basis of correlation analysis. Results: A total of 27 studies were included in this diploma thesis, in which 39 different trainings using blood flow restriction exercises were found and included. Based on the correlation analysis, no direct relationship was found between the exercise parameters and the magnitude of the...

Forelimbs of Day 11 and Day 12 embryonic mice were excised and cultured for 3 d in the presence of either 0.25 μg (8×10-7 M), 0.5 μg(1.7×10-6 M), or 1.0 μg (3.3×10-6 M) of all-rans retinoic acid (RA) per milliliter of culture medium. Cultured limbs were fixed, stained, and mounted whole on glass slides and evaluated with computerized optical image analysis for RA-induced effects on the area and shape of the total limb and individual bone anlagen. Relative effects of RA on total bone, soft tissue, long bone, and paw regions were also examined. With Day 11 forelimbs total bone area was increased by 10.5% by the low dose of RA. The increase was mostly in long bones and at the expense of soft tissue. Total bone area was increased 9.3% with Day 12 forelimbs. This increase was primarily in the paw. The high dose of RA decreased Day 11 forelimb area, primarily affecting long bones. Day 12 forelimbs were not significantly affected by the high dose of RA. Effects of the imtermediate dose were primarily limited to reduction in soft tissue area. Long bone:paw and soft tissue: bone ratios reflected these effects. The high dose produced a consistent rounding or shortening of Day 11 forelimb bones. On Day 12 0.5 μg/ml RA produced an inconsistent pattern of rounding of bone anlagen. Treatment with the high dose on Day 12 produced angular rather than rounded contours in many cases, as indicated by shape factor values closer to zero than obtained with controls. These data show that direct exposure to RA can affect both the size and shape of bone anlagen of the developing limb; the low dose enhances and the high dose depresses development. The results support previous studies which suggest that RA may play a critical role in the control of cell activities such as cell migration, proliferation, and cytodifferentiation in the development of the cartilaginous bone anlagen.

No description available.