The feasability of inertial measurement units (IMU) in capturing basic upper body motion

INTRODUCTION Three- Dimensional (3D) motion capture is accepted to be the gold standard approach to all data collection for the production of accurate data. Yet concerns over the ecological validity of 3D systems has come into question [1]. This has brought about the exploration of alternate methods such as inertial measurement units (IMU’s). The depth of research on IMU usage in wheelchair data collection is limited, particularly in comparison to an established data collection system, primarily focused around the use of IMU’s rather than validation studies aiming to ensure their reliability and accuracy. This single-subject pilot study aims to explore the feasibility of using IMU’s for capturing basic upper body motions during wheelchair propulsion. Specifically, to assess the potential limitations of IMUs in accurately measuring elbow and shoulder flexion. METHODS Several IMU (Vicon Blue Trident sensor, Vicon, Oxford, UK) placements and calibration stances were investigated for the collection of elbow flexion and shoulder flexion. The IMUs utilized were Vicon Blue Trident sensors (Vicon, Oxford, UK). IMUs were positioned at two locations for elbow flexion: at the wrist and centrally on the forearm. For shoulder flexion measurements, the IMU was situated 1 cm above the elbow joint. During the calibration phase, the participant assumed a standing anatomical position with their thumbs forwards, palms outwards, bent elbow and straight arms outwards at 90 degrees for elbow flexion and shoulder flexion respectfully. For both shoulder and elbow flexion, the participant started at a neutral position and proceeded to move through to 90 degrees of flexion and returned to starting position. Quintic biomechanical software (Quintic Biomechanics v25 Video Analysis Software, Quintic Consultancy, West Midlands, UK) was employed as the validated reference system for data comparison and analysis. RESULTS & DISCUSSION The wrist placed IMU determined elbow flexion more accurately than the forearm placed IMU. Range of motion for both shoulder and elbow flexion were well calculated within several degrees when using the anatomical thumbs forwards calibration pose; with 100.0 and 89.7° respectively compared to 88.5 and 97.3°. However, the degree of elbow flexion in relation to maximum values was overestimated with a difference of 27.8°, with the IMU being 91.1 degrees and quintic being 63.3°. Similar was also seen for the prediction of elbow flexion during the starting stance phase with a difference of 26.6 degrees. Shoulder flexion prediction was better calculated with a smaller difference of 6,6° between the IMU and Quintic for the thumbs forward calibration pose and 2.5 degrees for the palms forward calibration pose. For both shoulder and elbow flexion, the arms forward calibration stance resulted in large differences, with 14.6° and 75.1° difference in range of motion seen respectively. CONCLUSION With range of motion accurately calculated in comparison to quintic, and shoulder flexion maximum and minimum values also being similar when segment angle was calculated. Then the differences are likely due to error in the calculation of joint angle using a calculation of global coordinate system from the IMU coordinate system during data processing. Therefore, future research should target alternate approaches to data processing in order to reduce the errors seen. However, the accuracy in range of motion prediction, presents the scope for further research into the use of IMU’s in elements such as bilateral differences in range of motion during wheelchair activities. This potentially allows for their use in basic analysis of wheelchair propulsion and gives scope for investigation into factors such as ground type on basic upper body motion during wheelchair propulsion

Kinematic Profiles and Performance Insights of National-level Speed Climbers

INTRODUCTION Speed climbing, introduced as an Olympic sport in Tokyo 2020, uses a race format, where athletes ascend a standardised 15-meter wall as quickly as possible. The sport's recent growth underscores the need for a thorough understanding of the factors that influence success. Current knowledge characterises speed climbing as a rapid acceleration during the start phase, maintenance of high average velocities during the middle phase and concludes with a dyno, and a final jump to stop the timer [1]. This study investigates the relationship between performance and velocity, and acceleration profiles, aiming to elucidate techniques used by elite climbers and factors contributing to optimal performance. METHODS Two male national squad speed climbers participated in this case study. One Blue Trident IMU (Vicon, Motion Systems Ltd. Oxford, United Kingdom) was placed on the upper back of each climber. The athletes after a starting beep, climbed as quickly as possible on an internationally standard wall of 15.5 m with 31 holds (20 hand holds and 11 feet holds) and a touch pad to stop the timer. The IMUs tri-axial accelerometer (x = vertical, y = lateral, z = anteriorposterior) time series was used to calculate velocity and displacement. RESULTS & DISCUSSION Athlete A completed the speed climbing ascent in 8.72 seconds compared to 9.97 seconds for Athlete B. Athlete A demonstrated a peak acceleration of 20.6 m/s² during the start phase but experienced a notable drop from 2.9 m/s to 0.3 m/s over 0.4 seconds (Figure 1). Throughout the climb, Athlete A maintained relatively high velocities, peaking at 2.39 m/s in the mid phase and 1.47 m/s in the final stage. Athlete B achieved a peak acceleration of 17.0 m/s² during the start phase but did not exceed 0.5 m/s between 2.99- and 4.28-seconds. Athlete A’s superior start phase compared to Athlete B, indicating effective utilisation of handholds and lower limb power and emphasises the significance of generating high initial propulsion for rapid ascent [2]. During the mid and final phase, Athlete A demonstrated greater consistency in maintaining velocities. Athlete B experienced pronounced velocity drops, indicating challenges in velocity management and maintaining momentum. This is consistent with observations in climbing fluency literature, which suggests that deviations from the optimal climbing path and inefficient movement patterns can lead to energy loss and decreased performance [3]. Figure 1: Resultant displacement, velocity and acceleration during a training speed climb. CONCLUSION This study highlights the critical role of acceleration and velocity management in speed climbing success. By integrating insights from this study and leveraging IMU technology, athletes and coaches can develop targeted training strategies to enhance performance in speed climbing competitions

Using blogs to make peer-reviewed research more accessible

Discipline-based education researchers produce knowledge that aims to help instructors improve student learning and educational outcomes. Yet, the information produced may not even reach the educators it is intended to influence. Prior work has found that instructors often face barriers to implementing practices in peer-reviewed literature. Some of these barriers are related to accessing the knowledge in the first place such as difficulty finding and understanding research and a lack of time to do so. To lower these barriers, we created an online blog, PERbites, that summarizes recent discipline-based education research in short posts that use plain language. Having covered nearly 100 papers to date, we conducted a survey to see if we were addressing the need we had originally set out to address. We posted a 23-item survey on our website and received 24 usable responses. The results suggested that readers do generally agree that we are meeting our original goals. Readers reported that our articles were easier to understand and used more plain language than a typical discipline-based education research (DBER) journal article. At the same time, readers thought that all the important information was still included. Finally, readers said that this approach helped them keep up with DBER studies and read about papers they otherwise would not have. However, most readers did not indicate they changed their teaching and research practice as a result of reading our blog. Our results suggest that alternative methods of sharing research (e.g., non-peer reviewed publications or conference talks) can be an effective method of connecting research with practitioners, and future work should consider how we as a community might build on these efforts to ensure education research can make meaningful changes in the classroom.Comment: Published in the Proceedings of the 2022 Physics Education Research Conference, Grand Rapids, MI, US July 13th - July 14t

Wheelchair rugby players maintain sprint performance but alter propulsion biomechanics after simulated match play

The study aimed to explore the influence of a sports-specific intermittent sprint protocol (ISP) on wheelchair sprint performance and the kinetics and kinematics of sprinting in elite wheelchair rugby (WR) players with and without spinal cord injury (SCI). Fifteen international WR players (age 30.3 ± 5.5 years) performed two 10-s sprints on a dual roller wheelchair ergometer before and immediately after an ISP consisting of four 16-min quarters. Physiological measurements (heart rate, blood lactate concentration, and rating of perceived exertion) were collected. Three-dimensional thorax and bilateral glenohumeral kinematics were quantified. Following the ISP, all physiological parameters significantly increased (p ≤ 0.027), but neither sprinting peak velocity nor distance traveled changed. Players propelled with significantly reduced thorax flexion and peak glenohumeral abduction during both the acceleration (both -5°) and maximal velocity phases (-6° and 8°, respectively) of sprinting post-ISP. Moreover, players exhibited significantly larger mean contact angles (+24°), contact angle asymmetries (+4%), and glenohumeral flexion asymmetries (+10%) during the acceleration phase of sprinting post-ISP. Players displayed greater glenohumeral abduction range of motion (+17°) and asymmetries (+20%) during the maximal velocity phase of sprinting post-ISP. Players with SCI (SCI, n = 7) significantly increased asymmetries in peak power (+6%) and glenohumeral abduction (+15%) during the acceleration phase post-ISP. Our data indicates that despite inducing physiological fatigue resulting from WR match play, players can maintain sprint performance by modifying how they propel their wheelchair. Increased asymmetry post-ISP was notable, which may be specific to impairment type and warrants further investigatio

Early antenatal prediction of gestational diabetes in obese women: development of prediction tools for targeted intervention

All obese women are categorised as being of equally high risk of gestational diabetes (GDM) whereas the majority do not develop the disorder. Lifestyle and pharmacological interventions in unselected obese pregnant women have been unsuccessful in preventing GDM. Our aim was to develop a prediction tool for early identification of obese women at high risk of GDM to facilitate targeted interventions in those most likely to benefit. Clinical and anthropometric data and non-fasting blood samples were obtained at 15+0–18+6 weeks’ gestation in 1303 obese pregnant women from UPBEAT, a randomised controlled trial of a behavioural intervention. Twenty one candidate biomarkers associated with insulin resistance, and a targeted nuclear magnetic resonance (NMR) metabolome were measured. Prediction models were constructed using stepwise logistic regression. Twenty six percent of women (n = 337) developed GDM (International Association of Diabetes and Pregnancy Study Groups criteria). A model based on clinical and anthropometric variables (age, previous GDM, family history of type 2 diabetes, systolic blood pressure, sum of skinfold thicknesses, waist:height and neck:thigh ratios) provided an area under the curve of 0.71 (95%CI 0.68–0.74). This increased to 0.77 (95%CI 0.73–0.80) with addition of candidate biomarkers (random glucose, haemoglobin A1c (HbA1c), fructosamine, adiponectin, sex hormone binding globulin, triglycerides), but was not improved by addition of NMR metabolites (0.77; 95%CI 0.74–0.81). Clinically translatable models for GDM prediction including readily measurable variables e.g. mid-arm circumference, age, systolic blood pressure, HbA1c and adiponectin are described. Using a ≥35% risk threshold, all models identified a group of high risk obese women of whom approximately 50% (positive predictive value) later developed GDM, with a negative predictive value of 80%. Tools for early pregnancy identification of obese women at risk of GDM are described which could enable targeted interventions for GDM prevention in women who will benefit the most

VLT Observations of Turnoff stars in the Globular Cluster NGC 6397

VLT-UVES high resolution spectra of seven turnoff stars in the metal-poor globular cluster NGC 6397 have been obtained. Atmospheric parameters and abundances of several elements (Li, Na, Mg, Ca, Sc, Ti, Cr, Fe, Ni, Zn and Ba) were derived for program stars. The mean iron abundance is [Fe/H] = -2.02, with no star-to-star variation. The mean abundances of the alpha-elements (Ca, Ti) and of the iron-peak elements (Sc, Cr, Ni) are consistent with abundances derived for field stars of similar metallicity. Magnesium is also almost solar, consistent with the values found by Idiart & Th\'evenin (2000) when non-LTE effects (NLTE hereafter) are taken into account. The sodium abundance derived for five stars is essentially solar, but one object (A447) is clearly Na deficient. These results are compatible with the expected abundance range estimated from the stochastic evolutionary halo model by Argast et al. (2000) when at the epoch of [Fe/H] $\sim$ -2 the interstellar medium is supposed to become well-mixed.Comment: to appear in A&

Imaging of Oxidation-Specific Epitopes in Atherosclerosis and Macrophage-Rich Vulnerable Plaques

Oxidative stress, and in particular oxidation of lipoproteins, is a hallmark of atherosclerosis. Upon entry of lipoproteins into the vessel wall, a cascade of pro-atherogenic pathways is initiated whereby the reaction of reactive oxygen species with substrates amenable to oxidation, such as polyunsaturated fatty acids, generates a variety of oxidation-specific epitopes on lipoproteins, proteins in the vessel wall, and apoptotic macrophages. Several of these oxidation-specific epitopes have been well characterized and specific murine and fully human antibodies have been generated in our laboratory to detect them in the vessel wall. We have developed radionuclide, gadolinium and iron oxide based MRI techniques to noninvasively image oxidation-specific epitopes in atherosclerotic lesions. These approaches quantitate plaque burden and also allow detection of atherosclerosis regression and plaque stabilization. In particular, gadolinium micelles or lipid-coated ultrasmall superparamagnetic iron oxide particles containing oxidation-specific antibodies accumulate within macrophages in the artery wall, suggesting they may image the most unstable plaques. Translation of these approaches to humans may allow a sensitive technique to image and monitor high-risk atherosclerotic lesions and may guide optimal therapeutic interventions

Oxygen Abundances in Two Metal-Poor Subgiants from the Analysis of the 6300 A Forbidden O I Line

Recent LTE analyses (Israelian et al. 1998 and Bosegaard et al. 1999) of the OH bands in the optical-ultraviolet spectra of nearby metal-poor subdwarfs indicate that oxygen abundances are generally higher than those previously determined. The difference increases with decreasing metallicity and reaches delta([O/Fe]) ~ +0.6 dex as [Fe/H] approaches -3.0. Employing high resolution (R = 50000), high S/N (~ 250) echelle spectra of the two stars found by Israelian et al. (1998) to have the highest [O/Fe]-ratios, viz, BD +23 3130 and BD +37 1458, we conducted abundance analyses based on about 60 Fe I and 7-9 Fe II lines. We determined from Kurucz LTE models the values of the stellar parameters, as well as abundances of Na, Ni, and the traditional alpha-elements, independent of the calibration of color vs $T_{eff}$ scales. We determined oxygen abundances from spectral synthesis of the stronger line (6300 A) of the [O I] doublet. The syntheses of the [O I] line lead to smaller values of [O/Fe], consistent with those found earlier among halo field and globular cluster giants. We obtain [O/Fe] = +0.35 +/- 0.2 for BD +23 3130 and +0.50 +/- 0.2 for BD +37 1458. In the former, the [O I] line is very weak (~ 1 mA), so that the quoted [O/Fe] value may in reality be an upper limit. Therefore in these two stars a discrepancy exists between the [O/Fe]- ratios derived from [O I] and the OH feature, and the origin of this difference remains unclear. Until the matter is clarified, we suggest it is premature to conclude that the ab initio oxygen abundances of old, metal-poor stars need to be revised drastically upward.Comment: 38 pages, 5 tables, 14 figures To appear in July 1999 AJ Updated April 16, 1999. Fixed typo

The effect of a lifestyle intervention in obese pregnant women on gestational metabolic profiles: findings from the UK Pregnancies Better Eating and Activity Trial (UPBEAT) randomised controlled trial

Background: Pregnancy is associated with widespread change in metabolism, which may be more marked in obese women. Whether lifestyle interventions in obese pregnant women improve pregnancy metabolic profiles remains unknown. Our objectives were to determine the magnitude of change in metabolic measures during obese pregnancy, to indirectly compare these to similar profiles in a general pregnant population, and to determine the impact of a lifestyle intervention on change in metabolic measures in obese pregnant women. Methods: Data from a randomised controlled trial of 1158 obese (BMI ≥ 30 kg/m2) pregnant women recruited from six UK inner-city obstetric departments were used. Women were randomised to either the UPBEAT intervention, a tailored complex lifestyle intervention focused on improving diet and physical activity, or standard antenatal care (control group). UPBEAT has been shown to improve diet and physical activity during pregnancy and up to 6-months postnatally in obese women and to reduce offspring adiposity at 6-months; it did not affect risk of gestational diabetes (the primary outcome). Change in the concentrations of 158 metabolic measures (129 lipids, 9 glycerides and phospholipids, and 20 low-molecular weight metabolites), quantified three times during pregnancy, were compared using multilevel models. The role of chance was assessed with a false discovery rate of 5% adjusted p values. Results: All very low-density lipoprotein (VLDL) particles increased by 1.5–3 standard deviation units (SD) whereas intermediate density lipoprotein and specific (large, medium and small) LDL particles increased by 1–2 SD, between 16 and 36 weeks’ gestation. Triglycerides increased by 2–3 SD, with more modest changes in other metabolites. Indirect comparisons suggest that the magnitudes of change across pregnancy in these obese women were 2- to 3-fold larger than in unselected women (n = 4260 in cross-sectional and 583 in longitudinal analyses) from an independent, previously published, study. The intervention reduced the rate of increase in extremely large, very large, large and medium VLDL particles, particularly those containing triglycerides. Conclusion: There are marked changes in lipids and lipoproteins and more modest changes in other metabolites across pregnancy in obese women, with some evidence that this is more marked than in unselected pregnant women. The UPBEAT lifestyle intervention may contribute to a healthier metabolic profile in obese pregnant women, but our results require replication. Trial Registration: UPBEAT was registered with Current Controlled Trials, ISRCTN89971375, on July 23, 2008 (prior to recruitment)