Effect of coronavirus-19 restrictions in male handball players:physical activity, sedentary behavior, and satisfaction with life

This experiment examined physical activity (PA), sitting time, and satisfaction with life (SL) in European (45%) and Middle Eastern and North African (MENA; 55%) handball players (n = 418; age: 25.6 ± 6.8 years; body mass: 88.1 ± 11.7 kg; height: 1.83 ± 0.08 m) during the coronavirus (COVID)-19 pandemic. The International Physical Activity (IPAQ) and Satisfaction of Life (LS) Questionnaires were administered. All PA variables (vigorous, moderate, walking, total PA) were negatively influenced, but no interaction effects (IE; region x time) were observed. Sitting time increased from 2.5 to 4.9 h∙weekday−1 (ηp2 = 0.80) and walking time decreased from 66.8 to 33.5 min∙day−1 (ηp2 = 0.83). Based on effect sizes (d), pre- to during-confinement reductions were similar between regions (MENA: d = 3.29; Europe: d = 3.41; IE: ηp2 = 0.01). The largest regional difference was in moderate PA (MENA: d = 1.88; Europe: d = 2.99; IE: ηp2 = 0.09). SL in the total sample reduced from 30.6 ± 2.02 to 13.9 ± 2.20 arbitrary units (AU). SL reduction was similar in both regions (dMENA = 8.44; dEUROPE = 8.06; IE: ηp2 = 0.01). To conclude, PA decreased during COVID-19 confinement, sitting time increased, and SL decreased irrespective of geographical region. These preliminary findings highlight risk of SL and physical inactivity during COVID-19 restrictions in 2021

Effect of verbal instruction on motor learning ability of anaerobic and explosive exercises in physical education university students

This study investigated the effect of motor learning with informational feedback into response to anaerobic exercises with and without motor learning tasks in handball physical education university students. Participants were randomly divided into two groups: experimental group (EG, n = 10) and control group (CG, n = 10). Measurements of T-half test, 15-m and 30-m sprints, and ZIG-ZAG test were assessed in both groups before (T1), between (T2) a 4-week intervention program, and after (T3) an 8-week intervention program, which included agility and speed teaching with (EG) or without (CG) informational feedback (i.e., verbal instruction). The test-retest reliability for all tests was excellent, and the ICC ranged from 0.76 (ZIG-ZAG test) to 0.99 (Agility T test). The interday measurement error was clearly below 1% in all tests (CV range: 0.2–0.8). Time effects for the Agility T test (p = 0.012, η2p = 0.245) and the 15-m sprint (p = 0.035, η2p = 0.190) were found. For the Agility T test, a total interaction effect (p = 0.001, η2p = 0.380) and a partial interaction effect were calculated between T2 and T3 (p < 0.001, η2p = 0.603). A large effect size (d = 0.87) was observed in the EG from T2 to T3. The second relevant (d ≥ 0.5) effect size was calculated for the parameter sprint 30 m. The CG showed a significant sprint performance reduction from T2 to T3 (d = −0.60; parameter: sprint 30 m). All other effect sizes were less than 0.44. The ZIG-ZAG test revealed the largest main and partial effect sizes for all parameters. The EG showed the largest improvement (d = 2.00) between T2 and T3. The results demonstrate that motor learning with informational feedback improves performances of Agility T test, sprint, and ZIG-ZAG performance. It appears that a well-formulated verbal instruction may induce performance enhancement in young trainees in educational environment.The publication of this article was funded by the Qatar National Library. We thank Professor Mohamed Souhaiel Chelly [Research Unit (UR17JS01) “Sport Performance, Health & Society,” Higher Institute of Sport and Physical Education of Ksar Said, University of “La Manouba,” Tunisia] for his valuable experimental help

Evaluation of hydroxyapatite crystallization in a batch reactor for the valorization of alkaline phosphate concentrates from wastewater treatment plants using calcium chloride

In this work, phosphorous recovery as hydroxyapatite (Ca5(PO4)3OH(s) = Hap) from alkaline phosphate concentrates (0.25–1 g P–PO43-/L) using calcium chloride (6 g/L) in a batch reactor was evaluated. Ca(II) solutions was continuously fed (0.1–0.3 mL/min) up to reaching a Ca/P ratio of ~1.67 (5/3) to promote Hap formation. Hap powders were characterized by structural form (using X-ray diffraction (XRD), laser light scattering (LS) and Fourier transform infrared spectroscopy (FTIR)); textural form (using Field Emission Scanning Electron Microscopy with Energy Dispersive System (FE-SEM/EDS) and Brunauer–Emmett–Teller (BET)) and thermally (using Thermogravimetric Analysis (TGA)/Differential Thermal Analysis (DTA)). When pH was kept constant in alkaline values (from 8 to 11.5), Hap precipitation efficiency was improved. At pH 11.5, higher phosphorous precipitation rate was registered compared to that obtained for pH 8 and 10, but lower degree of crystallinity was observed in the Hap powders. The increase of the total initial phosphate concentration lead to the formation of Hap powders with higher degree of crystallinity and crystal diameter, but also lower mean particle size. As Ca(II) dosing rate increased Hap precipitation rate was higher, and also the mean size and degree of crystallinity of the prepared particles increasedPostprint (author’s final draft

Impact of functional group types in ion exchange resins on rare earth element recovery from treated acid mine waters

Ion-exchange (IX) resins incorporating single functional groups (sulfonic or amino-phosphonic) and two functional groups (sulfonic and phosphonic) were evaluated for selective recovery of Rare Earth Elements (REEs) from acidic mine waters (AMW). The composition of AMW solution, complexing properties of the functional group, and acidity were investigated as key parameters for concentration and separation of REEs from transition elements (TEs). Fe has to be removed from AMW to enable REE recovery and here the AMW was treated with NaOH solutions to reach pH 3.9 where Fe(III) was selectively removed (≤99%) by precipitation of schwertmannite. Single functional IX resin containing a sulfonic group displayed a higher REE recovery efficiency and separation ratio than observed for the bi-functional resin (sulfonic/phosphonic). Concentration factors for REEs between 30 and 40 were achieved using regeneration cycles with H2SO4. The performance of the aminophosphonic resin showed lower separation factors for REEs from TEs than the two resins containing sulfonic groups. IX resins performance was improved by tuning the acidity to match the functional group reactivity, where pH adjustment to the range of 0.5-2.0 provided the highest REE/TE separation factor for the single sulfonic resin followed by the bifunctional resin. The integration of an elution cycle using Na2-EDTA/NH4Cl mixtures strongly increases the concentration factors of REE and Light REE (LREE) concentration factors of up to 260 were achieved for the single functional sulfonic resin

Association of anthropometric qualities with vertical jump performance in elite male volleyball players

Aim: The objective of this study was to examine the association between physical and anthropometric profiles and vertical jump performance in elite volleyball players. Methods: Thirty-three elite male volleyball players (21±1 y, 76.9±5.2 kg, 186.5±5 cm) were studied. Several anthropometric measurements (body mass, stature, body mass index, lower limb length and sitting height) together with jumping height anaerobic power of counter movement jump with arm swing (CMJ arm)) were obtained from all subjects. Forward stepwise multiple linear regression analysis was performed to determine if any of the anthropometric parameters were predictive of CMJ arm. Results: Anaerobic power was significantly higher (P≤0.05) in the tallest players relative to their shorter counterparts. A significant relationship was observed between CMJ arm and lower limb length (r 2=0.69; P&lt;0.001) and between the lower limb length and anaerobic power obtained with CM-J arm(r 2=0.57; P&lt;0.01). While significantly correlated (P≤0.05) with CMJ arm performance, stature, lower limb length/stature and sitting height/stature ratios were not significant (P&gt;0.05) predictors of CMJ arm performance. Conclusion. This study demonstrates that lower limb length is correlated with CMJ arm in elite male volleyball players. The players with longer lower limbs have the better vertical jump performances and their anaerobic power is higher. These results could be of importance for trained athletes in sports relying on jumping performance, such as basketball, handball or volleyball. Thus, the measurement of anthropometric characteristics, such as stature and lower limb length may assist coaches in the early phases of talent identification in volleyball

Effects of plyometric and short sprint with change-of-direction training in male U17 soccer players

This project investigated the effect of adding 8 weeks of bi-weekly plyometric and short sprint with change-of-direction (PSSCoD) training into standard training for elite youth soccer players from Tunisia. A training group (n = 18; age: 16.6 ± 0.5 years; body mass: 63.2 ± 4.8 kg; stature: 1.73 ± 0.07 m; body fat: 11.2 ± 1.7%), and control group (n = 16; age: 16.6 ± 0.5 years; body mass: 63.6 ± 4.3 kg; height: 1.73 ± 0.06 m; body fat: 11.6 ± 1.5%) participated. The pre- and post-intervention measures were squat-jump (SJ), countermovement jump (CMJ), standing long jump (SLJ), 5 m and 20 m sprint, change-of-direction ability (4 × 5 m sprint test (S 4 × 5 m)), repeated sprint ability (RSA), and static balance (stork balance test). The training group displayed superior jump (all p &lt; 0.05; d &gt; 0.49), sprint (p &lt; 0.05; d &gt; 0.52), change-of-direction ability (p &lt; 0.01; d = 0.78), RSA (p &lt; 0.01; d &gt; 0.70), and static balance (p &lt; 0.05; d &gt; 0.49) improvements. Adding bi-weekly PSSCoD improves the athletic performance of young soccer players

Effect of Coronavirus-19 Restrictions in Male Handball Players: Physical Activity, Sedentary Behavior, and Satisfaction with Life

This experiment examined physical activity (PA), sitting time, and satisfaction with life (SL) in European (45%) and Middle Eastern and North African (MENA; 55%) handball players (n = 418; age: 25.6 ± 6.8 years; body mass: 88.1 ± 11.7 kg; height: 1.83 ± 0.08 m) during the coronavirus (COVID)-19 pandemic. The International Physical Activity (IPAQ) and Satisfaction of Life (LS) Questionnaires were administered. All PA variables (vigorous, moderate, walking, total PA) were negatively influenced, but no interaction effects (IE; region x time) were observed. Sitting time increased from 2.5 to 4.9 h∙weekday−1 (ηp2 = 0.80) and walking time decreased from 66.8 to 33.5 min∙day−1 (ηp2 = 0.83). Based on effect sizes (d), pre- to during-confinement reductions were similar between regions (MENA: d = 3.29; Europe: d = 3.41; IE: ηp2 = 0.01). The largest regional difference was in moderate PA (MENA: d = 1.88; Europe: d = 2.99; IE: ηp2 = 0.09). SL in the total sample reduced from 30.6 ± 2.02 to 13.9 ± 2.20 arbitrary units (AU). SL reduction was similar in both regions (dMENA = 8.44; dEUROPE = 8.06; IE: ηp2 = 0.01). To conclude, PA decreased during COVID-19 confinement, sitting time increased, and SL decreased irrespective of geographical region. These preliminary findings highlight risk of SL and physical inactivity during COVID-19 restrictions in 2021

Differences in Health-Related Physical Fitness and Academic School Performance in Male Middle-School Students in Qatar: A Preliminary Study

This study examined the differences in the level of physical fitness and academic performance among male middle-school children based on different body status categories. A total of 69 male children [age: 12.4 ± 0.7 years; body mass: 58.5 ± 7.2 kg; height: 1.62 ± 0.09 m; and body mass index (BMI): 22.4 ± 3.3 kg/m2] participated and were divided into BMI age-adjusted groups (i.e., lowest, middle, and highest BMI). Height, mass, BMI, stork test of static balance, 10 and 15 m sprint as an indicator for speed, hand-grip strength test, agility T-half test, medicine ball throw (MBT), and the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) were assessed. School records were retrieved for grade point averages (GPA) of mathematics, science, and Arabic. We found significant group differences regarding anthropometric (height: = 0.24, mass: = 0.33, and BMI: = 0.66), physical (sprint 10 m: = 0.26), and academic (mathematics: = 0.19 and science: = 0.15) performance parameters. The largest difference (p 0.5) correlation between parameters of different dimensions (e.g., anthropometric vs. physical performance parameters) was found. In conclusion, the highest BMI group exhibited similar physical and academic performances than the lowest group. Thus, these data emphasize the importance and appropriateness to engage young Qatari schoolchildren in physical activity as it associates with superior academic performance

Integrating crystallisation into transmembrane chemical absorption: Process intensification for ammonia separation from anaerobic digestate

In this study, reactive crystallisation is introduced into a liquid-liquid membrane contactor for the selective separation, purification and recovery of ammonia from concentrated waste. Whilst liquid-liquid membrane contactor technology has been previously demonstrated for ammonia absorption, further process intensification can be achieved by incorporating crystallisation into transmembrane chemisorption to recover the ammonia as crystalline ammonium sulphate. Reactive crystallisation occurred in the draw solution (sulphuric acid) which was supplied to the lumen-side of the polypropylene hollow-fibre. The ammonium sulphate concentration in the draw solution increased through ammonia mass transfer to supersaturation, at which time induction (the onset of nucleation) commenced. Ammonia mass transfer at draw concentrations above the solubility limit was not limited provided sufficient ‘free’ sulphate was available. This resulted in nucleation which occurred at a low level of supersaturation (C/C*, 1.03) to produce small crystals of around 2.5 μm, which indicated that nucleation was favoured. The nucleation rate was found to be proportional to the ammonia flux in the draw solution. As the solution became more saturated, crystal number increased but crystal growth was comparatively small; this is symptomatic of reactive crystallisation, where the rate of reaction exceeds the rate of mass transfer. Due to the large difference in the ratio between the lumen internal diameter and the mean crystal diameter (dfibre/dmean,CSD, ∼180), no fibre clogging was observed despite facilitating crystallisation on the lumen-side of the membrane. Transmembrane chemisorption crystallisation presents a feasible process intensification for the selective separation of ammonia from environmental applications. For its integration into environmental applications, solutions to wetting and fouling remain due to associative interactions with the complex organic matrix that are practically achievable through engineering intervention. Subsequent transformation of ammonia into a crystalline phase of ammonium sulphate presents a new product which is of commercial interest