Head supported mass, moment of inertia, neck loads and stability: A simulation study.

Occupations or activities where donning head-supported mass (HSM) is commonplace put operators at an elevated risk of chronic neck pain. Yet, there is no consensus about what features of HSM influence the relative contributions to neck loads. Therefore, we tested four hypotheses that could increase neck loads: (i) HSM increases gravitational moments; (ii) more muscle activation is required to stabilize the head with HSM; (iii) the position of the HSM centre of mass (COM) induces gravitational moments; and (iv) the added moment of inertia (MOI) from HSM increases neck loads during head repositioning tasks. We performed a sensitivity analysis on the C5-C6 compression evaluated from a 24-degree freedom cervical spine model in OpenSim for static and dynamic movement trials. For static trials, we varied the magnitude of HSM, the position of its COM, and developed a novel stability constraint for static optimization. In dynamic trials, we varied HSM and the three principle MOIs. HSM magnitude and compression were linearly related to one another for both static and dynamic trials, with amplification factors varying between 1.9 and 3.9. Similar relationships were found for the COM position, although the relationship between C5-C6 peak compression and MOI in dynamic trials was generally nonlinear. This sensitivity analysis uncovered evidence in favour of hypotheses (i), (ii) and (iii). However, the model's prediction of C5-C6 compression was not overly sensitive to the magnitude of MOI. Therefore, the HSM mass properties may be more influential on neck compression than MOI properties, even during dynamic tasks.

Building staff capability, opportunity, and motivation to provide smoking cessation to people with cancer in Australian cancer treatment centres: development of an implementation intervention framework for the Care to Quit cluster randomised controlled trial.

Few rigorous studies provide a clear description of the methodological approach of developing an evidence-based implementation intervention, prior to implementation at scale. This study describes the development, mapping, rating, and review of the implementation strategies for the Care to Quit smoking cessation trial, prior to application in nine cancer services across Australia. Key stakeholders were engaged in the process from conception through to rating, reviewing and refinement of strategies and principles. An initial scoping review identified 21 barriers to provision of evidence-based smoking cessation care to patients with cancer, which were mapped to the Theoretical Domains Framework and Behaviour Change Wheel (BCW) to identify relevant intervention functions. The mapping identified 26 relevant behaviour change techniques, summarised into 11 implementation strategies. The implementation strategies were rated and reviewed against the BCW Affordability, Practicality, Effectiveness and cost-effectiveness, Acceptability, Side-effects/safety, and Equity criteria by key stakeholders during two interactive workshops to facilitate a focus on feasible interventions likely to resonate with clinical staff. The implementation strategies and associated intervention tools were then collated by form and function to provide a practical guide for implementing the intervention. This study illustrates the rigorous use of theories and frameworks to arrive at a practical intervention guide, with potential to inform future replication and scalability of evidence-based implementation across a range of health service settings. Supplementary Information: The online version contains supplementary material available at 10.1007/s10742-022-00288-6.

Cervical Spine Motion Requirements From Night Vision Goggles May Play a Greater Role in Chronic Neck Pain than Helmet Mass Properties.

BACKGROUND: Chronic Neck Pain (CNP) among rotary-wing aircrew is thought to stem from night vision goggles (NVG) and counterweight (CW) systems which displace the centre of mass of the head. This investigation aimed to quantify the loads acting on the neck as a function of movement magnitude (MM), helmet conditions, and movement axes in rapid movements. METHODS: Cervical spine kinematics during rapid head repositioning tasks for flexion-extension (FE) and axial rotation (AR) movements were measured from 15 males and 15 females. Participants moved in either a 35° (Near MM) or 70° arc (Far MM), while donning a helmet, helmet with NVG, helmet with NVG and a typical CW, and a CW Liner (CWL). Measured EMG from three muscles bilaterally and used to drive a biomechanical model to quantify the compression and shear acting at the C5-C6 joint. RESULTS: In AR, the NVGs were associated with the largest compression magnitudes, 252 (24) N. CW conditions decreased the maximum compression to 249 (53) N. For FE, the compression was 340 N for the Far MM trials and 246 N for Near MMs. Changing the helmet configuration only modestly influenced these magnitudes in FE. CONCLUSION: Every 30° of MM increased compression by 57 to 105 N. The reduction of the moment of inertia by 16% in the CWL did not reduce reaction forces. Joint loads scaled proportionately with head-supported weight by a factor of 2.05. The magnitudes of loads suggest a cumulative loading pathway for CNP development.

Can We Quantify the Benefits of "Super Spikes" in Track Running?

The recent and rapid developments in track spike innovation have been followed by a wave of record-breaking times and top performances. This has led many to question what role "super spikes" play in improving running performance. To date, the specific contributions of new innovations in footwear, including lightweight, resilient, and compliant midsole foam, altered geometry, and increased longitudinal bending stiffness, to track running performance are unknown. Based on current literature, we speculate about what advantages these features provide. Importantly, the effects of super spikes will vary based on several factors including the event (e.g., 100 m vs. 10,000 m) and the characteristics of the athlete wearing them. Further confounding our understanding of super spikes is the difficulty of testing them. Unlike marathon shoes, testing track spikes comes with a unique challenge of quantifying the metabolic energy demands of middle-distance running events, which are partly anaerobic. Quantifying the exact benefits from super spikes is difficult and we may need to rely on comparison of track performances pre- and post- the introduction of super spikes.

Longitudinal bending stiffness does not affect running economy in Nike Vaporfly Shoes.

PURPOSE: This study aimed to determine the independent effect of the curved carbon-fiber plate in the Nike Vaporfly 4% shoe on running economy and running biomechanics. METHODS: Fifteen healthy male runners completed a metabolic protocol and a biomechanics protocol. In both protocols participants wore 2 different shoes, an intact Nike Vaporfly 4% (VFintact) and a cut Nike Vaporfly 4% (VFcut). The VFcut had 6 medio-lateral cuts through the carbon-fiber plate in the forefoot to reduce the effectiveness of the plate. In the metabolic protocol, participants ran at 14 km/h for 5 min, twice with each shoe, on a force-measuring treadmill while we measured metabolic rate. In the biomechanics protocol, participants ran across a runway with embedded force plates at 14 km/h. We calculated running economy, kinetics, and lower limb joint mechanics. RESULTS: Running economy did not significantly differ between shoe conditions (on average, 0.55% ± 1.77% (mean ± SD)) worse in the VFcut compared to the VFintact; 95% confidence interval (-1.44% to 0.40%). Biomechanical differences were only found in the metatarsophalangeal (MTP) joint with increased MTP dorsiflexion angle, angular velocity, and negative power in the VFcut. Contact time was 1% longer in the VFintact. CONCLUSION: Cutting the carbon-fiber plate and reducing the longitudinal bending stiffness did not have a significant effect on the energy savings in the Nike Vaporfly 4%. This suggests that the plate's stiffening effect on the MTP joint plays a limited role in the reported energy savings, and instead savings are likely from a combination and interaction of the foam, geometry, and plate.

Predicting Cervical Spine Compression and Shear in Helicopter Helmeted Conditions Using Artificial Neural Networks.

OCCUPATIONAL APPLICATIONSMilitary helicopter pilots around the globe are at high risk of neck pain related to their use of helmet-mounted night vision goggles. Unfortunately, it is difficult to design alternative helmet configurations that reduce the biomechanical exposures on the cervical spine during flight because the time and resource costs associated with assessing these exposures in vivo are prohibitive. Instead, we developed artificial neural networks (ANNs) to predict cervical spine compression and shear given head-trunk kinematics and joint moments in the lower neck, data readily available from digital human models. The ANNs detected differences in cervical spine compression and anteroposterior shear between helmet configuration conditions during flight-relevant head movement, consistent with results from a detailed model based on in vivo electromyographic data. These ANNs may be useful in helping to prevent neck pain related to military helicopter flight by facilitating virtual biomechanical assessment of helmet configurations upstream in the design process.

TECHNICAL ABSTRACTBackground: The use of night vision goggles (NVGs) has been linked to a high prevalence of neck pain and injury in military helicopter pilots. Next generation helmet designs aim to mitigate NVG related consequences on cervical spine loading. Currently, in vivo human-participant experiments are required to collect necessary data, such as electromyography (EMG) to estimate joint contact forces in the cervical spine as a result of unique helmet designs. This is costly and inefficient. Digital human models, which provide inverse dynamics, coupled with artificial neural networks (ANNs), can provide a surrogate for musculoskeletal joint modeling to predict joint contact forces.Purpose: We developed ANNs to predict C6-C7 compression and anteroposterior shear during flight-relevant head movements with sufficient sensitivity to differentiate between candidate helmet designs in terms of associated biomechanical exposures.Methods: Motion capture and EMG data were collected from 26 participants who performed flight-relevant reciprocal head movements about pitch and yaw axes while donning one of four helmet configurations. These data were input into an EMG-driven musculoskeletal model of the neck to generate time series of C6-C7 compression and shear. Rotation-specific ANNs were trained to predict the EMG-driven model outputs, given only the head-trunk kinematics and C6-C7 moments as inputs.Results: ANNs for pitch rotations were successful in estimating peak and cumulative compression and shear, with an absolute error that was lower than absolute differences in joint contact forces between relevant helmet conditions. ANNs for yaw rotations were similarly successful in differentiating between C6-C7 compression and cumulative C6-C7 shear, but less so for peak C6-C7 shear.Conclusions: When combined with biomechanical data readily available from digital human modeling software, use of an ANN surrogate for joint musculoskeletal modeling can permit evaluation of joint contact forces associated with novel helmet designs during upstream design. Improved consideration of joint contact forces during a virtual helmet design process will assist in identifying helmet designs that reduce biomechanical exposures of the cervical spine during helicopter flight.

Business as unusual: medical oncology services adapt and deliver during COVID-19.

BACKGROUND: The COVID-19 pandemic has challenged cancer care globally, introducing resource limitations and competing risks into clinical practice. AIMS: To describe the COVID-19 impact on medical oncology care provision in an Australian setting. METHODS: Calvary Mater Newcastle and Newcastle Private Hospital medical oncology data from 1 February to 31 April 2019 versus 2020 were retrospectively analysed. RESULTS: Three hundred and sixty-four inpatient admissions occurred in 2020, 21% less than in 2019. Total inpatient days decreased by 22% (2842 vs 2203). April was most impacted (36% and 44% fewer admissions and inpatient days respectively). Mean length of stay remained unchanged (6.4 vs 6.2 days, P = 0.7). In all, 5072 outpatient consultations were conducted, including 417 new-patient consultations (4% and 6% increase on 2019 respectively). Telephone consultations (0 vs 1380) replaced one-quarter of face-to-face consultations (4859 vs 3623, -25%), with minimal telehealth use (6 vs 69). Day Treatment Centre encounters remained stable (3751 vs 3444, -8%). The proportion of new patients planned for palliative treatment decreased (35% vs 28%, P = 0.04), observation increased (16% vs 23%, P = 0.04) and curative intent treatment was unchanged (both 41%). Recruiting clinical trials decreased by one-third (45 vs 30), two trials were activated (vs 5 in 2019) and 45% fewer patients consented to trial participation (62 vs 34). CONCLUSION: Our medical oncology teams adapted rapidly to COVID-19 with significant changes to care provision, including fewer hospital admissions, a notable transition to telephone-based outpatient clinics and reduced clinical trial activity. The continuum of care was largely defended despite pandemic considerations and growing service volumes.

Energetics and Biomechanics of Running Footwear with Increased Longitudinal Bending Stiffness: A Narrative Review.

In the wake of the quest to break the 2-h marathon barrier, carbon-fiber plates have become commonplace in marathon racing shoes. Despite the controversy surrounding this shoe technology, studies on the effects of increased longitudinal bending stiffness on running economy report mixed results. Here, we provide a comprehensive review of the current literature on midsole bending stiffness and carbon-fiber plates in distance running shoes, focusing on how longitudinal bending stiffness affects running energetics and lower limb mechanics. The current literature reports changes in running economy with increased longitudinal bending stiffness ranging from ~ 3% deterioration to ~ 3% improvement. In some studies, larger improvements have been observed, but often those shoes varied in many aspects, not just longitudinal bending stiffness. Biomechanically, increased longitudinal bending stiffness has the largest impact on metatarsal-phalangeal (MTP) and ankle joint mechanics. Plate location [top loaded (an insole), embedded (in between midsole foam), and bottom loaded (along the bottom of the shoe)] and geometry (flat/curved) affect joint moments and angular velocities at the MTP and ankle joint differently, which partly explains the mixed running economy results. Further research investigating how carbon-fiber plates interact with other footwear features (such as foam and midsole geometry), scaling of those with shoe size, body mass, and strike pattern, and comparing various plate placements is needed to better understand how longitudinal bending stiffness affects running economy.

Night Vision Goggle and Counterweight Use Affect Neck Muscle Activity During Reciprocal Scanning.

BACKGROUND: Mass, moment of inertia, and amplitude of neck motion were altered during a reciprocal scanning task to investigate how night vision goggles (NVGs) use mechanistically is associated with neck trouble among rotary-wing aircrew.METHODS: There were 30 subjects measured while scanning between targets at 2 amplitudes (near and far) and under 4 head supported mass conditions (combinations of helmet, NVGs, and counterweights). Electromyography (EMG) was measured bilaterally from the sternocleidomastoid and upper neck extensors. Kinematics were measured from the trunk and head.RESULTS: Scanning between the far amplitude targets required higher peak angular accelerations (7% increase) and neck EMG (between 1.24.5% increase), lower muscle cocontraction ratios (6.7% decrease), and fewer gaps in EMG (up to a 59% decrease) relative to the near targets. Increasing the mass of the helmet had modest effects on neck EMG, while increasing the moment of inertia did not.DISCUSSION: Target amplitude, not head supported mass configuration, had a greater effect on exposure metrics. Use of NVGs restricts field-of-view, requiring an increased amplitude of neck movement. This may play an important role in understanding links between neck trouble and NVG use.Healey LA, Derouin AJ, Callaghan JP, Cronin DS, Fischer SL. Night vision goggle and counterweight use affect neck muscle activity during reciprocal scanning. Aerosp Med Hum Perform. 2021; 92(3):172181.

A Microfluidic Device to Enhance Viral Transduction Efficiency During Manufacture of Engineered Cellular Therapies.

The development and approval of engineered cellular therapies are revolutionizing approaches to treatment of diseases. However, these life-saving therapies require extensive use of inefficient bioprocessing equipment and specialized reagents that can drive up the price of treatment. Integration of new genetic material into the target cells, such as viral transduction, is one of the most costly and labor-intensive steps in the production of cellular therapies. Approaches to reducing the costs associated with gene delivery have been developed using microfluidic devices to increase overall efficiency. However, these microfluidic approaches either require large quantities of virus or pre-concentration of cells with high-titer viral particles. Here, we describe the development of a microfluidic transduction device (MTD) that combines microfluidic spatial confinement with advective flow through a membrane to efficiently colocalize target cells and virus particles. We demonstrate that the MTD can improve the efficiency of lentiviral transduction for both T-cell and hematopoietic stem-cell (HSC) targets by greater than two fold relative to static controls. Furthermore, transduction saturation in the MTD is reached with only half the virus required to reach saturation under static conditions. Moreover, we show that MTD transduction does not adversely affect cell viability or expansion potential.