Evaluation of physical fitness in 11 years old students in Northern Italy: a powerful tool to improve physical education curricula

Purpose: This study was designed to evaluate the physical fitness (PF) in 11 years old students of 7 schools in Brescia. The aim was to provide functional data useful for motor activity promotion by physical education (PE) teaching in middle-lower school. Methods: To assess the four main components of the PF we measured: (1) anthropometric data, i.e. height (m), weight (kg) to calculate BMI (kg/m2); (2) aerobic fitness through the six minutes walking test (6MWT); (3) muscular fitness through the standing broad jump test (SBJT); (4) joint flexibility from the V-Sit and reach test (VSR). Statistical analysis was performed by 2-way ANOVA. Results: 349 children were tested, 257 Italian (I) and 74 Not-Italian (NI); I: 127 males (M) and 130 females (F); NI: 41 M and 33 F. NI children belonged to different ethnic groups. BMI I-M (19.3 +- 3.3) I-F (19.5 +- 3.7) NI-M (20.7 +- 3.6) NI-F (19.9 +- 4.5) 6MWT I-M (720 +- 59) I-F (697 +- 54) NI-M (704 +- 75) NI-F (683 +- 52) SBJT I-M (154 +- 22) I-F (144 +- 21) NI-M (145 +- 24) NI-F (137 +- 21) VSR I-M (- 7 +- 7) I-F (4 +-10) NI-M (- 5 +- 8) NI-F (- 1 +- 10) Statistical differences between groups. BMI I vs NI; M-I vs M-NI; SBJT I vs NI; M(I + NI) vs F(I + NI); M-I vs F-I; VSR M(I + NI) vs F(I + NI); M(I) vs F(I) Conclusions: I group data. BMI mean value of both M and F is close to the 50th percentile according to a previous study concerning North of Italy children. Nonetheless, 15% of M and 11% of F have to be considered overweight [1]. 6MWT and SBJT mean results are even better than those reported for other age-matched European children [2, 3]. VSR data are strongly influenced by gender. M show marked negative results, while F show good flexibility. This difference should be considered in PE curriculum. NI group data. Only two of the PF descriptors are different compared to I data, being BMI and SBJT value higher and lower, respectively, than those of I counterpart. Generally, the resulting overall PF of the investigated students is in line with the literature data. The level of PF can be considered adequate, making this population able to follow PE curriculum aimed to include physical activity in daily life as a tool to discourage its abandon in adulthood. References Cacciari E et al (2002) Eur J Clin Nutr 56:171–180 Ulrich S et al (2013) BMC Pulm Med 13:49–60 Ortega FB et al (2011) Br J Sports Med 45:20–2

Motor unit conduction velocity at different joint angles

Purpose: The aim of this study was to evaluate the dependence of motor unit conduction velocity (MUCV) on the length of the muscle. Methods: Muscle length was modified considering three different ankle angles: 90°,110° and 130°. For each angle the maximal voluntary contraction (MVC) was measured during static ankle dorsiflexion. High-density surface electromyography (HD-sEMG, 128 channels) was recorded from the tibialis anterior muscle (TA) in six young individuals. Subjects executed a volitional effort in which the output tension changed in a trapezoidal ramp fashion (15 s transient and 40 s steady contraction). Two levels of steady contraction were investigated: 10% and 20% of MVC. Using a novel decomposition technique based on HD-sEMG processing (Negro et al. 2016), the individual MUCV values were estimated during the trapezoid steady part. The decomposition was performed at each ankle angle independently, and the MU action potentials were not tracked across different muscle lengths. Results: MVC mean values at 90° and 130° were 91.78% and 78.77% of 110° value respectively. Considering that there was no statistical difference between the MUCV estimations calculated at 10 and 20% MVC, the values were grouped. The average CV was 4.00 ± 0.54 m/ s for 90°, 3.88 ± 0.19 m/s for 110° and 3.77 ± 0.37 m/s for 130°. One-Way Anova analysis showed a weak effect between the three conditions (P = 0.04). Conclusion: MUCV changes were weakly related to the different muscle lengths. Explanation of our results should consider that the muscle fiber can be approximated as a constant volume system and that, from the cable theory, the smaller the diameter the lower the CV is. On these bases, the reduction of muscle fibers transverse diameter during muscle elongation when the ankle angle increases from 90° to 130° could be a possible explanation for our results

Remote sensing-based estimation of gross primary production in a subalpine grassland

This study investigates the performances in a terrestrial ecosystem of gross primary production (GPP) estimation of a suite of spectral vegetation indexes (VIs) that can be computed from currently orbiting platforms. Vegetation indexes were computed from near-surface field spectroscopy measurements collected using an automatic system designed for high temporal frequency acquisition of spectral measurements in the visible near-infrared region. Spectral observations were collected for two consecutive years in Italy in a subalpine grassland equipped with an eddy covariance (EC) flux tower that provides continuous measurements of net ecosystem carbon dioxide (CO2) exchange (NEE) and the derived GPP. Different VIs were calculated based on ESA-MERIS and NASA-MODIS spectral bands and correlated with biophysical (Leaf area index, LAI; fraction of photosynthetically active radiation intercepted by green vegetation, f IPARg), biochemical (chlorophyll concentration) and ecophysiological (green light-use efficiency, LUEg) canopy variables. In this study, the normalized difference vegetation index (NDVI) was the index best correlated with LAI and f IPARg (r = 0.90 and 0.95, respectively), the MERIS terrestrial chlorophyll index (MTCI) with leaf chlorophyll content (r = 0.91) and the photochemical reflectance index (PRI551), computed as (R531 −R551)/(R531 +R551) with LUEg (r = 0.64). Subsequently, these VIs were used to estimate GPP using different modelling solutions based on Monteith’s lightuse efficiency model describing the GPP as driven by the photosynthetically active radiation absorbed by green vegetation (APARg) and by the efficiency (") with which plants use the absorbed radiation to fix carbon via photosynthesis. Results show that GPP can be successfully modelled with a combination of VIs and meteorological data or VIs only. Vegetation indexes designed to be more sensitive to chlorophyll content explained most of the variability in GPP in the ecosystem investigated, characterised by a strong seasonal dynamic of GPP. Accuracy in GPP estimation slightly improves when taking into account high frequency modulations of GPP driven by incident PAR or modelling LUEg with the PRI in model formulation. Similar results were obtained for both measured daily VIs and VIs obtained as 16-day composite time series and then downscaled from the compositing period to daily scale (resampled data). However, the use of resampled data rather than measured daily input data decreases the accuracy of the total GPP estimation on an annual basis.JRC.H.4-Monitoring Agricultural Resource

Optic Atrophy 1 Is Epistatic to the Core MICOS Component MIC60 in Mitochondrial Cristae Shape Control

The mitochondrial contact site and cristae organizing system (MICOS) and Optic atrophy 1 (OPA1) control cristae shape, thus affecting mitochondrial function and apoptosis. Whether and how they physically and functionally interact is unclear. Here, we provide evidence that OPA1 is epistatic to MICOS in the regulation of cristae shape. Proteomic analysis identifies multiple MICOS components in native OPA1-containing high molecular weight complexes disrupted during cristae remodeling. MIC60, a core MICOS protein, physically interacts with OPA1, and together, they control cristae junction number and stability, OPA1 being epistatic to MIC60. OPA1 defines cristae width and junction diameter independently of MIC60. Our combination of proteomics, biochemistry, genetics, and electron tomography provides a unifying model for mammalian cristae biogenesis by OPA1 and MICOS.We thank Drs. F. Caicci and F. Boldrin (EM Facility, Department of Biology, University of Padova) for EM and ALEMBIC, San Raffaele Scientific Institute, for tomography. L.S. is a senior scientist of the Dulbecco-Telethon Institute. Support was provided by Telethon-Italy (GGP15091 and GGP14187), AIRC Italy (ERC FP7-282280), FP7 CIG (PCIG13-GA-2013-618697), the Italian Ministry of Research (FIRB RBAP11Z3YA\_005), the Italian Ministry of Health (GR-2009-1600051 to L.S.), a University of Padua grant for a postdoctoral fellowship (2015 to M.E.S.), and an International Brain Research Organization-International Society for Neurochemistry research fellowship (2016 to A.M.).S

Sex-differences in the longitudinal recovery of neuromuscular function in COVID-19 associated acute respiratory distress syndrome survivors

IntroductionPatients admitted to the intensive care unit (ICU) following severe acute respiratory syndrome 2 (SARS-CoV-2) infection may have muscle weakness up to 1 year or more following ICU discharge. However, females show greater muscle weakness than males, indicating greater neuromuscular impairment. The objective of this work was to assess sex differences in longitudinal physical functioning following ICU discharge for SARS-CoV-2 infection.MethodsWe performed longitudinal assessment of physical functioning in two groups: 14 participants (7 males, 7 females) in the 3-to-6 month and 28 participants (14 males, 14 females) in the 6-to-12 month group following ICU discharge and assessed differences between the sexes. We examined self-reported fatigue, physical functioning, compound muscle action potential (CMAP) amplitude, maximal strength, and the neural drive to the tibialis anterior muscle.ResultsWe found no sex differences in the assessed parameters in the 3-to-6-month follow-up, indicating significant weakness in both sexes.Sex differences emerged in the 6-to-12-month follow-up. Specifically, females exhibited greater impairments in physical functioning, including lower strength, walking lower distances, and high neural input even 1 year following ICU-discharge.DiscussionFemales infected by SARS-CoV-2 display significant impairments in functional recovery up to 1 year following ICU discharge. The effects of sex should be considered in post-COVID neurorehabilitation

Electrophysiological neuromuscular alterations and severe fatigue predict long-term muscle weakness in survivors of COVID-19 acute respiratory distress syndrome

IntroductionLong-term weakness is common in survivors of COVID-19-associated acute respiratory distress syndrome (CARDS). We longitudinally assessed the predictors of muscle weakness in patients evaluated 6 and 12 months after intensive care unit discharge with in-person visits.MethodsMuscle strength was measured by isometric maximal voluntary contraction (MVC) of the tibialis anterior muscle. Candidate predictors of muscle weakness were follow-up time, sex, age, mechanical ventilation duration, use of steroids in the intensive care unit, the compound muscle action potential of the tibialis anterior muscle (CMAP-TA-S100), a 6-min walk test, severe fatigue, depression and anxiety, post-traumatic stress disorder, cognitive assessment, and body mass index. We also compared the clinical tools currently available for the evaluation of muscle strength (handgrip strength and Medical Research Council sum score) and electrical neuromuscular function (simplified peroneal nerve test [PENT]) with more objective and robust measures of force (MVC) and electrophysiological evaluation of the neuromuscular function of the tibialis anterior muscle (CMAP-TA-S100) for their essential role in ankle control.ResultsMVC improved at 12 months compared with 6 months. CMAP-TA-S100 (P = 0.016) and the presence of severe fatigue (P = 0.036) were independent predictors of MVC. MVC was strongly associated with handgrip strength, whereas CMAP-TA-S100 was strongly associated with PENT.DiscussionElectrical neuromuscular abnormalities and severe fatigue are independently associated with reduced MVC and can be used to predict the risk of long-term muscle weakness in CARDS survivors

Motor output relative error during static linear maximal torque ramp: influence of the age

Aim To evaluate if the torque output relative error during linearly varying static contractions can be influenced by possible changes in motor unit properties and activation/deactivation strategies (MUAS and MUDS) due to the ageing process. Method Eleven young (Y, 23.90 ± 3.72 years) and eleven old (O, 69.63 ± 4.34 years) subjects were recruited for the study. After the first dorsal interosseous (FDI) maximal voluntary contraction (MVC) during static abduction, the subject performed one triangular isometric contraction (0-100-0 %). The rate of the up-going (UGR) and down-going ramp (DGR) was 13.3% MVC/s. The requested output tension (% MVC target) was provided on a PC screen together with the force from the subject for the necessary visual feedback. The global, positive and negative relative errors (E%) were calculated for the whole triangle and for the up going and down-gong phases separately according to the formula E%= absolute value of (exerted - requested target force)/requested force*100. The filtered force signal (bandwidth: 0-20 Hz) was analyzed using the Spike Shape Analysis (SSA) technique. Statistical significance of the calculated parameters between Y and O was set at p<0.05. Results As reported in the table the calculated E% were always greater in old subjects. The SSA reported lower number of longer spikes, with similar absolute amplitude, in O with respect to Y subjects. When the spike amplitude is scaled to the individual MVC the spikes of O subjects are greater than in Y. Conclusion MUAS and MUDA adopted by Y and O subjects determine a different a more precise motor output in Y than in O. The key factors may be: I. the larger number of error correction (reflected in the spike number) and II. the larger motor unit size due to the muscle fibers reinnervation process with age (reflecting the larger relative spike amplitude in O compared to Y)

Effects of marathon fatigue on the discharge rates of individual motor units in older adults

Aim: Age-related changes in motor unit properties are essential to understand muscle behavior after exercise in older adults. In this study, we compared the changes in motor unit discharge rates during steady isometric contractions before and after a half-marathon in elderly individuals. Methods: During the event Run4Science, we recorded high-density surface electromyography (HD-sEMG, 128 channels) on the tibialis anterior muscle (TA) in eight old subjects. Subjects executed a 40 seconds static dorsiflexion at 25% MVC. The test was performed in two consecutive days, the first under non-fatigue conditions before half-marathon (BM) and the second immediately after half-marathon (AM). Using a novel decomposition technique for HD-sEMG recordings (Negro at al. 2016), we compared the changes in the discharge properties of the TA motor units before and after the half marathon. We calculated the global average discharge rate value (GADR) of all MUs in the two conditions. Only MU pulse trains with a silhouette measure > 0.9 were used in the study. Results: We extracted the individual contribution of 486 unmatched MUs (~ 30 per contraction). The GADR were 13.43 ± 1.46 (pps) and 14.89 ± 1.67(pps) for the BM and AM conditions respectively. Paired T-test analysis showed a significant difference between conditions (P<0.05). Conclusion: The results showed that the discharge rates of the identified MUs increase after the half-marathon. Future work will focus on the tracking of the same MU in the two conditions (Martinez‐Valdes 2017) in order to increase the sensitivity of the estimation