Skeletal loading: implications for injury and treatment

Physical activity is important for the overall health of individuals. Impacts that occur when the foot hits the ground have the potential to be an influential factor in both the etiology of overuse injury and the promotion of bone health. Stress injury to bone is considered the ultimate overuse injury and accounts for the nearly one fourth of injuries in active populations. This dissertation evaluates bone loading in three ways: in vivo strain gage measurement, a combination of experimental and modeling techniques, and tibial accelerometry. Emphasis was placed on the clinical implication of findings from such techniques on the treatment and prevention of bone stress injury. The first study assessed the influence of orthotics on bone strain. The results of this study indicated that bone strain and strain rates were minimized with the use of orthotics. Secondly, the use of custom orthotics was more effective in minimization of strains and strain rates than semi-custom orthotics. The second and third studies used a combination of experimental data and musculoskeletal modeling to estimate combined loading, internal bone forces, moments and stresses. The findings from these studies were 1) the tibia is predominately undergoes in-phase loading of axial and torsional loads 2) gait mechanics can independently influence bone stresses and stress rates in the distal tibia 3) runners with a history of stress fracture demonstrate only moderately elevated internal bone forces and moments in the distal tibia. The final study of this dissertation evaluated injury more globally and assessed variability of stride time output. The patterned behavior of stride time variability was sensitive to fatigue and group differences. The results of these studies add to an ever growing body of knowledge of gait and injury and suggest that the internal loads of bone can be influenced by external support and gait mechanics. However, the multifactoral nature of injury cannot be ignored in the study of stress fracture. Additionally, fatigue and injury status play a role in the neuromuscular control system output during running and influence overall gait dynamics

Tibial stress during running following a repeated calf‐raise protocol

This is the author accepted manuscript. The final version is available on open access from Wiley via the DOI in this recordTibial stress fractures are a problematic injury amongst runners. Increased loading of the tibia has been observed following prolonged weight‐bearing activity and is suggested to be the result of reduced activity of the plantar flexor muscles. The musculature that spans the tibia contributes to bending of the bone and influences the magnitude of stress on the tibia during running. Participant‐specific models of the tibia can be used as a non‐invasive estimate of tibial stress. This study aimed to quantify tibial stress during running using participant‐specific bone geometry and to compare tibial stress before and after a protocol of repeated muscular contractions of the plantar flexor muscle group. Fourteen participants who run recreationally were included in the final analysis of the study. Synchronised force and kinematic data were collected during overground running before and after an exhaustive, weighted calf‐raise protocol. Bending moments and stress at the distal third of the tibia were estimated using beam theory combined with inverse dynamics and musculoskeletal modelling. Bone geometry was obtained from magnetic resonance images. There was no difference in stress at the anterior, posterior, medial or lateral peripheries of the tibia after the calf‐raise protocol compared with before. These findings suggest that an exhaustive, repeated calf‐raise protocol did not alter tibial stress during running

SARS-CoV-2-specific immune responses and clinical outcomes after COVID-19 vaccination in patients with immune-suppressive disease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune responses and infection outcomes were evaluated in 2,686 patients with varying immune-suppressive disease states after administration of two Coronavirus Disease 2019 (COVID-19) vaccines. Overall, 255 of 2,204 (12%) patients failed to develop anti-spike antibodies, with an additional 600 of 2,204 (27%) patients generating low levels (<380 AU ml−1). Vaccine failure rates were highest in ANCA-associated vasculitis on rituximab (21/29, 72%), hemodialysis on immunosuppressive therapy (6/30, 20%) and solid organ transplant recipients (20/81, 25% and 141/458, 31%). SARS-CoV-2-specific T cell responses were detected in 513 of 580 (88%) patients, with lower T cell magnitude or proportion in hemodialysis, allogeneic hematopoietic stem cell transplantation and liver transplant recipients (versus healthy controls). Humoral responses against Omicron (BA.1) were reduced, although cross-reactive T cell responses were sustained in all participants for whom these data were available. BNT162b2 was associated with higher antibody but lower cellular responses compared to ChAdOx1 nCoV-19 vaccination. We report 474 SARS-CoV-2 infection episodes, including 48 individuals with hospitalization or death from COVID-19. Decreased magnitude of both the serological and the T cell response was associated with severe COVID-19. Overall, we identified clinical phenotypes that may benefit from targeted COVID-19 therapeutic strategies

Accuracy of the SenseWear Armband during Short Bouts of Exercise

A goal of mobile monitoring is to approximate metabolic energy expenditure (EE) during activities of daily living and exercise. Many physical activity monitors are inaccurate with respect to estimated EE and differentiating between activities that occur over short intervals. The objective of our study was to assess the validity of the SenseWear Armband (SWA) compared to indirect calorimetry (IC) during short intervals of walking and running. Twenty young, fit participants walked (preferred speed) and ran (75%, 85%, and 95% of predicted VO2max run speeds) on a treadmill. EE estimates from IC, SWA, and prediction equations that used the SWA, speed, and heart rate were examined during each 4 min interval and across the whole protocol (Total). The level of significance was p −1 while walking and 1.05 kcal·min−1 while running at 75%. However, it underestimated EE at the 85% (0.05 kcal·min−1) and 95% (0.92 kcal·min−1) speeds, but not significantly, and overestimated total EE by 28.29 kcal. Except for walking, our results suggest that the SWA displayed a good level of agreement (ICC = 0.76 to 0.84) with IC measures. Activity-specific algorithms using SWA, speed, and heart rate improved EE estimates, based on the standard error of the estimates, but perhaps not enough to justify extra sensors. The SWA may enable EE estimation of locomotion outside the laboratory, including those with short bouts of high intensity activity, but continued development of the SWA, or devices like it, is needed to enable accurate monitoring

PLEASE SCROLL DOWN FOR ARTICLE Ergonomics The effects of age and type of carrying task on lower extremity kinematics

To cite this Article Gillette, Jason C. , Stevermer, Catherine A. , Miller, Ross H. , Meardon, Stacey A. andSchwab, Charles V.(2010) 'The effects of age and type of carrying task on lower extremity kinematics ', Ergonomics, 53: 3,[355][356][357][358][359][360][361][362][363] Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. The purpose of this study was to determine the effects of age, load amount and load symmetry on lower extremity kinematics during carrying tasks. Forty-two participants in four age groups (8-10 years, 12-14 years, 15-17 years and adults) carried loads of 0%, 10% and 20% body weight (BW) in large or small buckets unilaterally and bilaterally. Reflective markers were tracked to determine total joint range of motion and maximum joint angles during the stance phase of walking. Maximum hip extension, hip adduction and hip internal rotation angles were significantly greater for each of the child/adolescent age groups as compared with adults. In addition, maximum hip internal rotation angles significantly increased when carrying a 20% BW load. The observation that the 8-10-year-old age group carried the lightest absolute loads and still displayed the highest maximum hip internal rotation angles suggests a particular necessity in setting carrying guidelines for the youngest children. Statement of Relevance: Bucket-carrying tasks were analysed as a function of age group, load amount and load symmetry. Hip joint rotations significantly increased when carrying 20% BW loads and in children as compared to adults, which suggests a particular necessity in setting carrying guidelines for the youngest age group (8-10 year olds)