Aligning Organizational Priorities and System Policies to Support Implementation Scale-Up of a Tailored Classroom-Based Physical Activity Intervention in Low-Resource Schools

BACKGROUND

A mismatch between organizational priorities and system-level policies can negatively impact implementation and sustainment of classroom-based physical activity (PA) interventions. The purpose of this study was twofold: (1) present methods to systematically identify organization- and system-level implementation barriers, and (2) align organizational priorities and system policies by designing multi-level implementation strategies. This alignment will support implementation scale-up of a tailored PA intervention in one low-resource intermediate school district (ISD; 16 districts, 32 schools) in central Michigan.

METHODS

Multi-level assessments of organizational readiness were conducted using the Hexagon Discussion and Analysis Tool to assess intervention-context fit, the Wellness School Assessment Tool 3.0 to evaluate district PA policy strength and comprehensiveness, and semi-structured interviews were conducted to assess administrative support and priorities related to PA programming.

RESULTS

Our assessments revealed three implementation barriers: limited structural capacity to sustain teacher training, limited resources across districts and school buildings to support teachers, and misalignment of ISD and district PA policies and priorities.

CONCLUSIONS

Greater attention to organizational capacity and existing infrastructure should be considered a priori to support effective implementation and sustainment of PA interventions in low-resource schools.

Rapid cycle adaptation of a classroom-based intervention to promote equity in access to youth physical activity

Our objective was to systematically adapt Interrupting Prolonged sitting with ACTivity (InPACT), a classroom-based physical activity intervention, for home delivery to equitably increase access to structured youth physical activity opportunities during the COVID-19 pandemic. Key steps in the rapid-cycle research adaptation process included: (Step 1) identifying partner organizations; (Steps 2 and 3) engaging in problem and knowledge exploration to examine the problem from different perspectives; (Steps 4 and 5) initiating solution development and testing by selecting an intervention and adapting the format and content for home delivery. Using Rapid RE-AIM to guide online assessment and refinement of InPACT at Home; and (Step 6) utilizing dissemination strategies to extend the reach of the program. Core elements of the InPACT program that were retained included: the use of exercise videos, maintenance of the intervention dose, and teacher-led physical activities. Key adaptations included: utilization of physical education specialists to develop the exercise videos, incorporation of health messaging in videos, and utilization of dissemination strategies (intervention website) to reach K-12 students across the state. Intervention website reach included all 83 counties in Michigan, but goals were not met for website pageviews (5,147; 85% of goal) and video view duration (7 min 19 sec; 37% of goal). Accordingly, dissemination was expanded to include public television broadcasting (monthly viewers: 500,000) and videos were shortened to 8 minutes. Dissemination and implementation science frameworks guided the rapid adaptation of an existing intervention, InPACT, to equitably increase access to structured youth physical activity opportunities at home during the pandemic.

Mechanisms of bone remodeling during weight-bearing exercise

Exercise-induced mechanical loading can have potent effects on skeletal form and health. Both intrinsic and extrinsic factors contribute to bone structure and function. Mechanical simuli (e.g., strain magnitude, frequency, rate, and gradients, as well as fluid flow and shear stress) have potent influences on bone-cell cytoskeleton and associated signalling pathways. Although the immature skeleton may be more able to benefit from exercise, a skeletally mature population can also benefit from exercise programs aimed at increasing the functional loads to which the skeleton is exposed. The definitive explanation of mechanical-loading and (or) bone-cell mechanotransductive phenomena, however, remains elusive. Here, we briefly review the structural and anatomical foundation for bone adaptation, focusing on mechanical loading effects on bone, linked to the roles of integrins, cytoskeleton, membrane channels, and auto- and paracrine factors in bone modeling and remodeling.

Scoliotic progression patterns in prognostic factors and future prediction of spinal deformity progression

This study investigated how an adolescent idiopathic scoliosis progresses with time. 154 consecutive measurements from 26 consecutive AIS patients were analyzed. Each subject had at least four successive scans at six-month intervals. Progression patterns of Cobb angle and apex lateral deviation were extracted from 34 serial data sets of the most common AIS type RT-LL, in the format of four serial data sets, by using the fuzzy c-means clustering technique. Progression of spinal deformity was predicted with previous serial data of Cobb angle and apex lateral deviation by using a GCV extrapolating technique alone and in conjunction with progression patterns. Our results showed that scoliotic progression appears to follow progression patterns. Progression of spinal deformity has potential to be accurately predicted with previous serial spinal deformities by using GCV extrapolating technique with assistance of progression patterns.

Transplantation of articular cartilage following a step-cooling cryopreservation protocol

Using a step-cooling cryopreservation protocol that held the tissue 60 min at -4 degrees C, 30 min at -8 degrees C, and 10 min at -40 degrees C before plunging into liquid nitrogen, we were able to get a substantial improvement in the magnitude and pattern of chondrocyte recovery following cryopreservation, achieving postthaw recoveries of 62 +/- 13%. These results are consistent with the hypothesis that ice growth within articular cartilage is planar, but they provide no direct support for that hypothesis. Transplanting (step-cooled) cryopreserved osteochondral allografts into adult Suffolk/Romanoff crossbred sheep for periods of 3 months and 1 year further tested the efficacy of the cryopreservation protocol. Unfortunately, the cryoinjury sustained by the chondrocytes during cryopreservation, although apparently nonlethal immediately after thawing in many cases, was not innocuous in the long term. The presence of large clusters of chondrocytes at 1 year after transplantation illustrates that cryoinjury not detectable with a membrane integrity assay can still have far-reaching effects on transplanted tissue.

Measurement of cancellous bone strain during mechanical tests using a new extensometer device

A device for measuring mid-substance strain in bone during uniaxial compression was developed with special attention to subsequent FE modelling. It is based on dual instrumented cantilever arms that measure the difference in tip-to-tip deflection. The so-called extensometer device was compared to two standard methods of measuring strain based on platen measurements. The extensometer device output was highly linear with tip deflection (r(2)>0.99), and contact of the devices with the specimen was optimized by using an axial distribution of three devices fixed in a free-floating jig. Deflection of the extensometer arms was accurate to 4.8 microm, and precision was between 2-5 microm. Tests included measuring rubber test specimens and cylindrical cancellous bone cores extracted from canine femoral condyles. A trend of decreasing apparent modulus with decreasing strain rate was evident with the extensometer technique. Correlation between the extensometer method and the other two methods was r(2)=0.55. The measure of mid-substance strain avoids non-linearities in the compression tests caused by early failure at the specimen ends, and the uniaxial testing conditions result in boundary conditions that are well suited for subsequent finite element analysis.

Cryobiology of articular cartilage: ice morphology and recovery of chondrocytes

The cryopreservation of articular cartilage chondrocytes has been achieved with cells isolated from the cartilage matrix but has found only limited success when the tissue is left intact. Previous work with ovine cartilage has shown that cryopreservation of the chondrocytes of the superficial and deep zones is possible, but the cells of the intermediate zone have not been successfully cryopreserved. This finding led to the suggestion that there might be biological differences between chondrocytes of the different morphological zones that were responsible for this differential recovery. This study investigates the hypothesis that the cells of the intermediate zone are more sensitive to cryoinjury by introducing cuts in the cartilage so that cells of the intermediate zone have the same proximity to the outer surface of the tissue as the cells of the superficial zone. When this was done, it was found that cells of the intermediate zone could survive cryopreservation as well as the cells of the superficial zone when they were near a surface, but not when they were embedded deep within the tissue. Thus the hypothesis of a biological difference between the cells of the two zones being responsible for the differential recovery is disproved. It is further hypothesized that physical proximity to a surface leads to higher recovery as a result of planar ice growth into the cartilage.

Mechanical load stimulates expression of novel genes in vivo and in vitro in avian flexor tendon cells

OBJECTIVE

Our experiments were designed to test the hypothesis that tendon cells might respond differently to applied strain in vitro than in vivo.

DESIGN

We tested cells in whole tendons from exercised chickens and from isolated surface (TSC) and internal tendon (TIF) in vitro that were subjected to mechanical strain. We hypothesized that tendon cells differentially express genes in response to mechanical loading in vivo and in vitro.

METHODS

We utilized an in-vivo exercise model in which chickens were run on a treadmill in an acute loading regime for 1 h 45 min with the balance of time at rest to 6 h total time. Gene expression was analyzed by a differential display technique. In addition, isolated avian flexor digitorum profundus TSC and TIF cells were subjected to cyclic stretching at 1 Hz, 5% average elongation for 6 h, +/- PDGF-BB, IGF-I, TGF-beta 1, PTH, estrogen, PGE2, or no drug and/or no load. mRNA was then collected and samples were subjected to differential display analysis.

CONCLUSIONS

Load with or without growth factor and hormone treatments induced expression of novel genes as well as some known genes that were novel to tendon cells. We conclude that the study of gene expression in mechanically loaded cells in vivo and in vitro will lead to the discovery of novel and important marker proteins that may yield clues to positive and negative cell strain responses that are protective under one set of conditions and destructive under another.

Energy expenditure during walking by children who have proximal femoral focal deficiency

The energy expended during walking by sixteen children who had proximal femoral focal deficiency was measured to compare the outcomes after Syme amputation (seven subjects) with those after Van Nes rotational osteotomy (nine subjects). Multivariate regression analysis revealed that the subjects who had had a Van Nes procedure had a mean oxygen cost (energy per unit of body mass expended per distance walked) that was 0.12 milliliter per kilogram of body mass per meter lower than that of the subjects who had had a Syme amputation (p = 0.001). The subjects who had had a Van Nes procedure tended to walk faster (p = 0.07). A significant decrease in the oxygen cost as a function of increasing age was observed for both groups (p < 0.0001, r2= 0.79). We believe that the reduced energy expenditure associated with the Van Nes rotational osteotomy is one of several factors to consider when deciding which operation should be done for children who have proximal femoral focal deficiency.

Site and mechanical conditions for failure of skeletal muscle in experimental strain injuries

Failure in muscle strain injuries has been reported to occur within the muscle belly, at the myotendinous junction, or within muscle near the myotendinous junction. The goal of this investigation was to determine by electron-microscopic examination the site of lesion in whole muscle strained to failure. In addition, site and conditions for failure of stimulated and unstimulated muscle were compared. Frog semitendinosus myotendinous units with intact tendon-bone junctions were strained at physiological strain rates to failure. All failures occurred at or near the proximal myotendinous junction in both stimulated and unstimulated muscle. Stimulated muscle required approximately 30% more force and approximately 110% more energy to reach failure. Electron-microscopic examination of longitudinal sections of small bundles of fibers showed that unstimulated muscle failed within the muscle near the myotendinous junction. Failure occurred in a single transverse plane of each cell within Z disks. Other Z disks near the failure site displayed strains of several hundred percent. Stimulated muscle failed within the lamina lucida at the myotendinous junction in most fibers. No Z-disk strain was observed in those fibers. We conclude that the site of failure in muscle strain injuries varies with the state of activation of the cell at the time of injury. Furthermore, the data show that the breaking strength of the Z disk varied with muscle stimulation and indicate the existence of two load-bearing systems in parallel within Z disks.

Effects of mild diabetes on immature cortical bone

Diabetes mellitus can adversely affect bone, and clinical data show that cortical bone can respond differentially to the systemic effects of diabetes, with distal bones more adversely affected in diabetic osteoarthropathy. To examine the differential effects of diabetic osteoarthropathy on distal and proximal immature bones we examined the morphological and biomechanical characteristics of tibia and second metatarsus of streptozotocin-induced diabetic rats. Female Sprague-Dawley rats (8 weeks) were randomly divided into three groups: control, diabetes, and diabetes with insulin therapy for 10 weeks. The right tibia and metatarsus were tested in three-point bending to failure, and contralateral bones were used for morphological analyses. Length, mid-diaphyseal cross-sectional geometry, and mechanical properties of the experimental tibiae were typically not significantly different from the control. The diabetes with insulin metatarsus was generally no different morphologically and mechanically from control, but the diabetes metatarsus structural properties and medullary cross-sectional area were significantly less than control. The percent of the cortical cross-sectional area accounted for by the periosteal band, however, was significantly greater in the diabetes metatarsus.

RELEVANCE

Results highlight the bone-specific, proximal versus distal alterations that occur with diabetes mellitus. Insulin treatment mitigated the adverse effects that mild, streptozotocin-induced diabetes had on rat cortical bone.