AIM: To describe the bowel habits and the prevalence of irritable bowel syndrome(IBS) and to investigate the influence of health behavior and social factors on IBS prevalence in university students. METHODS: This cros...AIM: To describe the bowel habits and the prevalence of irritable bowel syndrome(IBS) and to investigate the influence of health behavior and social factors on IBS prevalence in university students. METHODS: This cross-sectional study was conducted at five major universities in Greater Beirut and its suburbs, between February and June 2014. Using a convenience sample, a total of 813 students aged 18 years old and above participated in this study. Participants were asked to complete a comprehensive anonymous questionnaire which detailed characteristics on socio-demographic, health-related, and lifestyle factors, as well as IBS. The ROME Ⅲ criteria were used as a tool to ascertain IBS. A χ2 test was used to determine differences between categorical variables; stepwise logistic regression was used to measure the association between IBS and its risk factors.RESULTS: An overall prevalence of IBS of 20% was recorded among university students. The bivariate analysis showed that females were significantly more likely to report having IBS than males(29.1% vs 18.2%, P < 0.01). Those living at the school dormitory or in a private residence(39.5%) were more likely to have IBS than those living with their families(16.3%)(P < 0.01). The multivariate analysis showed that those who had a relatively high family income level(US$ > 2000) were almost 6 times more likely to report havingIBS than their counterparts.CONCLUSION: This is the first study to describe the nature of IBS among young adults in Lebanon. The prevalence of IBS among university students in our sample was higher than that reported in the West.展开更多
The aim of this study was to quantify the effect of torsion deformity on the lower limb kinetics during the loading response phase of gait. A total of 24 subjects: 6 end-staged medial knee OA with torsion deformity (T...The aim of this study was to quantify the effect of torsion deformity on the lower limb kinetics during the loading response phase of gait. A total of 24 subjects: 6 end-staged medial knee OA with torsion deformity (TKO), 8 without torsion deformity (KOA), and 10 controls (CON) were imaged using computed tomography (CT). Internal moment of support and sagittal hip, knee and ankle joint moments were assessed using gait analysis. TKO showed greater external rotations of the proximal tibia and the distal femur compared to subjects with medial knee OA without torsion deformity and controls. TKO showed greater moment of support and a greater knee extensor moment when compared to controls when supporting the weight of the body during gait. The TKO intorsion deformity occurred as a result of a proximal malrotation of the tibia. In the presence of torsion deformity, the kinetic synergy of the lower limb showed increased total moment of support for subjects with medial knee OA. The greater extensor output from TKO may be the result of an increased muscular response to overcome an interrupted inter-segmental exchange of accelerations during the loading response phase of gait.展开更多
The purpose of this study was to determine the associations between urinary estradiol (E2) metabolite concentration and medial knee loading with radiographic disease severity in middle aged women with initial stage kn...The purpose of this study was to determine the associations between urinary estradiol (E2) metabolite concentration and medial knee loading with radiographic disease severity in middle aged women with initial stage knee osteoarthritis (OA). Women presenting with knee pain were recruited into a cross-sectional correlation study (KOA, n = 9, age = 52 ± 4 yrs). Self report menstrual history, the Modified Baecke Questionnaire and the Knee Injury and Osteoarthritis Outcome Score (KOOS) subjective data were collected. A fasting blood sample (follicle stimulating hormone (FSH) and Tumor Necrosis Factor-α (TNF-α)), and urine catch (16α-hydroxyestrone and 2-hydroxyestrone) were collected. Gait analysis using an 8-camera motion analysis system assessed internal knee varus moment and foot progression angle. Pearson Product moments tested for associations between urinary 16α-hydroxyestrone and 2-hydroxyestrone, TNF-α, medial knee loading, and radiographic disease severity (Kellgren/Lawrence (K/L) radiographic score). Significant correlations were found within the hormonal biomarkers (r = 0.94, p p p = 0.31). No correlations were found for radiographic disease severity or TNF-α. The lack of association between hormonal and biomechanical variables could be due to large variability of the E2 metabolites seen in the menopause transition and the limited structural changes of initial staged knee OA.展开更多
Background: Previous studies have demonstrated psychosocial and physical benefit from exercise for older men treated with androgen deprivation therapy (ADT) for prostate cancer (PCa). To date, different intervention d...Background: Previous studies have demonstrated psychosocial and physical benefit from exercise for older men treated with androgen deprivation therapy (ADT) for prostate cancer (PCa). To date, different intervention delivery methods have not been assessed. This study compared the effect of group-based exercise (GBE) to personal training (PT) in men undergoing ADT for PCa. Methods: 13 participants (mean age = 68.2, SD = 7.2) were randomly assigned to GBE or PT for 8 weeks. Participants exercised for 60 minutes three times per week at a moderate-vigorous intensity. Results: 10 participants completed the intervention. At post-intervention, the PT group improved: fatigue, systolic BP, waist circumference, body fat percentage, and maximal leg strength;participants in the GBE group improved leg strength. At 8 weeks, maximal upper body strength in the PT group was greater than the GBE group. There were no adverse events associated with moderate-high intensity training in this population of older men. Conclusion: PT may be more efficacious than GBE in improving several physical fitness outcomes and fatigue in men with PCa who are androgen deprived. Due to the small sample size and attrition, these results require cautious interpretation and confirmation from adequately powered trials.展开更多
Purpose:To quantify differences in nonlinear aspects of performance on a seated visual-motor tracking task between clinically asymptomatic males and females with and without a self-reported mild traumatic brain injury...Purpose:To quantify differences in nonlinear aspects of performance on a seated visual-motor tracking task between clinically asymptomatic males and females with and without a self-reported mild traumatic brain injury history.Methods:Seventy-three individuals with a self-reported concussion history(age:21.40±2.25 years,mean±SD)and 75 without completed the visual-motor tracking task(age:21.50±2.00 years).Participants pressed an index finger against a force sensor,tracing a line across a computer screen(visual-motor tracking).The produced signal's root-mean-square error(RMSE),sample entropy(SampEn,a measure of regularity),and average power(AvP)between 0 and 12 Hz were calculated.Results:Males with a history of 0 or 1 concussion had greater RMSE(worse performance)than females with 0(p<0.0001)and 1 concussion(p=0.052).Additionally,females with 2+concussions exhibited lower SampEn than females with no history(p=0.001)or a history of 1 concussion(p=0.026).Finally,females with 2+concussions had lower 8-12 Hz AvP than males with 2+concussions(p=0.031).Few differences were observed in the male participants.Conclusion:Females with a self-reported history of multiple concussions exhibited lower SampEn in the visual-motor tracking-task force output structure as compared to those with no reported history of concussion and their male counterparts.Lower SampEn and lower power between 8 and12 Hz indicated persistent impairment in visual processing and feed-forward or predictive motor control systems.展开更多
Relative risk is a popular measure to compare risk of an outcome in the exposed group to the unexposed group. By applying the delta method and Central Limit Theorem, [1] derives two approximate confidence intervals fo...Relative risk is a popular measure to compare risk of an outcome in the exposed group to the unexposed group. By applying the delta method and Central Limit Theorem, [1] derives two approximate confidence intervals for the relative risk, and [2] approximates the confidence interval for the relative risk via the likelihood ratio statistic. Both of these approximations require sample size to be large. In this paper, by adjusting the likelihood ratio statistic obtained by [2], a new method is proposed to obtain the confidence interval for the relative risk. Simulation results showed that the proposed method is extremely accurate even when the sample size is small.展开更多
Training specificity is imperative for successful performance of the elite athlete.Virtual reality(VR)has been successfully applied to a broad range of training domains.However,to date there is little research investi...Training specificity is imperative for successful performance of the elite athlete.Virtual reality(VR)has been successfully applied to a broad range of training domains.However,to date there is little research investigating the use of VR for sport training.The purpose of this study was to address the question of whether virtual reality(VR)training can improve real world hockey shooting performance.Twenty four volunteers were recruited and randomly selected to complete the virtual training intervention or enter a control group with no training.Four primary types of data were collected:(1)participant’s experience with video games and hockey,(2)participant’s motivation toward video game use,(3)participant’s technical performance on real-world hockey,and(4)participant’s technical performance in virtual hockey.One-way multivariate analysis of variance(ANOVA)indicated that the intervention group demonstrated significantly more real-world hockey accuracy(F(1,24)=15.43,p<0.01,E.S.=0.56)while shooting on goal than their control group counterparts(intervention M accuracy=54.17%,SD=12.38,control M accuracy=46.76%,SD=13.45).One-way multivariate analysis of variance(MANOVA)repeated measures indicated significantly higher outcome scores on real-world accuracy(35.42%versus 54.17%;ES=1.52)and velocity(51.10 mph versus 65.50 mph;ES=0.86)of hockey shooting on goal.This research supports the idea that virtual training is an effective tool for increasing real-world hockey skill.展开更多
This special issue highlights comprehensive reviews and researches on topics in fundamentally important areas of skeletal muscle physiology.1–6 The most important adaptive response of skeletal muscle to exercise,part...This special issue highlights comprehensive reviews and researches on topics in fundamentally important areas of skeletal muscle physiology.1–6 The most important adaptive response of skeletal muscle to exercise,particularly resistant exercise,is increased protein synthesis,which is critical for promoting muscle hypertrophy and/or preventing atrophy.This process plays an essential role in promoting and maintaining skeletal muscle contractile and metabolic functions.展开更多
Aim Portable devices that accurately detect the composition of expired gases and changes in VO_(2)open new possibilities in research methodology and accessibility.Purpose The purpose of this study was to compare the o...Aim Portable devices that accurately detect the composition of expired gases and changes in VO_(2)open new possibilities in research methodology and accessibility.Purpose The purpose of this study was to compare the oxygen consumption(VO_(2))measurements of the VO_(2)Master Pro(VM)to the Cosmed K5(K5)during walking,jogging,and running in field and lab conditions.Methods Twelve proficient runners,with a current 10 k pace of≥11.29 km/h,performed 3 matched intervals at 3 different speeds(4.82,8.05,11.29 km/h)on a treadmill and on an outdoor track.An airflow test was also performed on both devices by pumping air through the devices using a 3 L syringe timed to a metronome at 15,25,and 35 beats/min.Results The VM did not report walking data for most participants.During treadmill running,there were significant differences in VO_(2)(47.86±3.94 vs.29.56±4.15 mL/kg/min),ventilation(V_(e))(71 vs.57 mL/min),and tidal volume(TV)(1.89 vs.1.56 L)between the K5 and VM respectively(P<0.05).Outdoor analysis also showed significant differences between devices in VO_(2),V_(e),and TV(P<0.05).The airflow test showed significant differences between the devices in V_(e)and TV(P<0.05).Conclusion These results suggest that there are significant discrepancies between the K5 and the VM,likely due to differ-ences in TV measurement.展开更多
Mitochondria are essential energy-providing organelles that are required in the maintenance of healthy skeletal muscle.As such,the removal of damaged mitochondria,through mitophagy,is necessary to maintain mitochondri...Mitochondria are essential energy-providing organelles that are required in the maintenance of healthy skeletal muscle.As such,the removal of damaged mitochondria,through mitophagy,is necessary to maintain mitochondrial quality.In aging muscle,mitochondrial content and function are often found to be reduced compared to young individuals.This occurs despite the fact that measures of mitophagy are elevated,suggesting that mitophagy is insufficiently high to remove all of the dysfunctional organelles in aging muscle.Recent evidence has shown that acute exercise promotes mitophagic signaling,leading to organelle degradation.This exercise-induced signaling is attenuated in aging muscle,suggesting that aging muscle loses its capacity for mitochondrial turnover in response to exercise.This contributes to the reduction in muscle health in elderly individuals.Chronic exercise training improves mitochondrial content and function,even in aging muscle,leading to reduced mitophagy signaling.Thus,exercise training should be prescribed for both young and elderly populations to pro-mote the maintenance of a healthy mitochondrial pool,through the stimulation of both organelle biogenesis and mitophagy.展开更多
A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for hig...A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for high-level myoelectric-based hierarchical control is proposed.A Recurrent Neural Network(RNN)was trained using output data,initially obtained from offline optimization of the biomechatronic(human–robot)device and shifted by the prediction horizon.The input of the RNN consisted of interrupted sEMG signals(to mimic signal disconnections)and previous kinematic signals of the assistive system.The RNN with a 0.1-s prediction horizon could predict the control-oriented joint angle and assistive torque with 92%and 86.5%regression accuracy,respectively,for the test dataset.This proposed approach permits a fast,predictive,and direct estimation of control-oriented signals instead of an iterative process that optimizes assistive torque in the inverse dynamic simulation of a multibody human–robot system.Training with these interrupted input signals significantly improves the regression accuracy in the case of sEMG signal disconnection.This Robust Predictive Control-oriented Machine Learning(Robust-MuscleNET)model can support volitional high-level myoelectric-based control of biomechatronic devices,such as exoskeletons,prostheses,and assistive/resistive robots.Future work should study the application to prosthesis control as well as the repeatability of the high-level controller with electrode shift.The low-level hierarchical controller that manages the human–robot interaction,the assistance/resistance strategy,and the actuator coordination should also be studied.展开更多
The surface glycoprotein hemagglutinin (HA) helps the influenza A virus to evade the host immune system by antigenic variation and is a major driving force for viral evolution. In this study, the selection pressure on...The surface glycoprotein hemagglutinin (HA) helps the influenza A virus to evade the host immune system by antigenic variation and is a major driving force for viral evolution. In this study, the selection pressure on HA of H5N1 influenza A virus was analyzed using bioinformatics algorithms. Most of the identified positive selection (PS) sites were found to be within or adjacent to epitope sites. Some of the identified PS sites are consistent with previous experimental studies, providing further support to the biological significance of our findings. The highest frequency of PS sites was observed in recent strains isolated during 2005–2007. Phylogenetic analysis was also conducted on HA sequences from various hosts. Viral drift is almost similar in both avian and human species with a progressive trend over the years. Our study reports new mutations in functional regions of HA that might provide markers for vaccine design or can be used to predict isolates of pandemic potential.展开更多
Neisseria meningitidis is the agent of invasive meningococcal disease, including cerebral meningitis and septicemia. Because the diseases caused by different clonal groups (sequence types) have their own epidemiologic...Neisseria meningitidis is the agent of invasive meningococcal disease, including cerebral meningitis and septicemia. Because the diseases caused by different clonal groups (sequence types) have their own epidemiological characteristics, it is important to understand the differences among the genomes of the N. meningitidis clonal groups. To this end, a novel interpretation of a structural dot plot of genomes was devised and applied; exact nucleotide matches between the genomes of N. meningitidis serogroup A strain Z2491 and serogroup B strain MC58 were identified, leading to the specification of various structural regions. Known and putative virulence genes for each N. meningitidis strain were then classified into these regions. We found that virulence genes of MC58 tend more to the translocated regions (chromosomal segments in new sequence contexts) than do those of Z2491, nota- bly tending towards the interface between one of the translocated regions and the collinear region. Within the collinear region, virulence genes tend to occur within 16 kb of gaps in the exact matches. Verification of these tendencies using genes clustered in the cps locus was sufficiently supportive to suggest that these tendencies can be used to focus the search for and understanding of virulence genes and mechanisms of pathogenicity in these two organisms.展开更多
Introduction The bench press is commonly used to measure upper-body strength.While much emphasis has been placed on the upper-body,little is known about how the lower-body can play a role in bench press performance.Le...Introduction The bench press is commonly used to measure upper-body strength.While much emphasis has been placed on the upper-body,little is known about how the lower-body can play a role in bench press performance.Leg-drive is a technique that includes flexing the knee so the feet line up posterior to the knee joint,while simultaneously contracting the knee extensors isometrically during the lift.The purpose of this study was to compare strength characteristics of lifters in a standard bench press versus a leg-drive bench press over the course of 5-weeks of training.Methods Twenty-three recreationally active males(age:22.4±2.1 years,height:175.0±5.9 cm,mass:78.4±9.5 kg)were randomized into a standard bench or leg-drive bench press group.Participants performed four sets to failure,two times per week for five weeks.Variables of interests were training volume and 1-repetition maximum(1RM)strength.For training volume,a 2×5(group×week)repeated measures analysis of variance(RMANOVA)was used.For the 1RM’s,a 2×2×2(group×press type×time)RMANOVA was used.A priori alpha levels were set to 0.05.Results Over time,both groups showed an approximate 6%increase in 1RM strength.Training volume for week 4 was 5.6%less than week 5,but was not different from weeks 1 through 3.No between-group differences were observed for 1RM strength or training volume.Conclusion This results of this work indicates that 5 weeks of leg-drive training is effective in increasing 1RM strength,but was not more effective than standard bench press training.Practically,lifters should choose either lifting style based on personal preference.展开更多
Mitochondria are vital organelles that provide energy for muscle function.When these organelles become dysfunctional,they produce less energy as well as excessive levels of reactive oxygen species which can trigger mu...Mitochondria are vital organelles that provide energy for muscle function.When these organelles become dysfunctional,they produce less energy as well as excessive levels of reactive oxygen species which can trigger muscle atrophy,weakness and loss of endurance.In this review,molecular evidence is provided to show that exercise serves as a useful therapeutic countermeasure to overcome mitochondrial dysfunction,even when key regulators of organelle biogenesis are absent.These findings illustrate the complexity and compensatory nature of exercise-induced molecular signaling to transcription,as well as to post-transcriptional events within the mitochondrial synthesis and degradation(i.e.turnover)pathways.Beginning with the first bout of contractile activity,exercise exerts a medicinal effect to improve mitochondrial health and whole muscle function.展开更多
基金Supported by Pathophysiology Research Unit at the Lebanese University
文摘AIM: To describe the bowel habits and the prevalence of irritable bowel syndrome(IBS) and to investigate the influence of health behavior and social factors on IBS prevalence in university students. METHODS: This cross-sectional study was conducted at five major universities in Greater Beirut and its suburbs, between February and June 2014. Using a convenience sample, a total of 813 students aged 18 years old and above participated in this study. Participants were asked to complete a comprehensive anonymous questionnaire which detailed characteristics on socio-demographic, health-related, and lifestyle factors, as well as IBS. The ROME Ⅲ criteria were used as a tool to ascertain IBS. A χ2 test was used to determine differences between categorical variables; stepwise logistic regression was used to measure the association between IBS and its risk factors.RESULTS: An overall prevalence of IBS of 20% was recorded among university students. The bivariate analysis showed that females were significantly more likely to report having IBS than males(29.1% vs 18.2%, P < 0.01). Those living at the school dormitory or in a private residence(39.5%) were more likely to have IBS than those living with their families(16.3%)(P < 0.01). The multivariate analysis showed that those who had a relatively high family income level(US$ > 2000) were almost 6 times more likely to report havingIBS than their counterparts.CONCLUSION: This is the first study to describe the nature of IBS among young adults in Lebanon. The prevalence of IBS among university students in our sample was higher than that reported in the West.
文摘The aim of this study was to quantify the effect of torsion deformity on the lower limb kinetics during the loading response phase of gait. A total of 24 subjects: 6 end-staged medial knee OA with torsion deformity (TKO), 8 without torsion deformity (KOA), and 10 controls (CON) were imaged using computed tomography (CT). Internal moment of support and sagittal hip, knee and ankle joint moments were assessed using gait analysis. TKO showed greater external rotations of the proximal tibia and the distal femur compared to subjects with medial knee OA without torsion deformity and controls. TKO showed greater moment of support and a greater knee extensor moment when compared to controls when supporting the weight of the body during gait. The TKO intorsion deformity occurred as a result of a proximal malrotation of the tibia. In the presence of torsion deformity, the kinetic synergy of the lower limb showed increased total moment of support for subjects with medial knee OA. The greater extensor output from TKO may be the result of an increased muscular response to overcome an interrupted inter-segmental exchange of accelerations during the loading response phase of gait.
文摘The purpose of this study was to determine the associations between urinary estradiol (E2) metabolite concentration and medial knee loading with radiographic disease severity in middle aged women with initial stage knee osteoarthritis (OA). Women presenting with knee pain were recruited into a cross-sectional correlation study (KOA, n = 9, age = 52 ± 4 yrs). Self report menstrual history, the Modified Baecke Questionnaire and the Knee Injury and Osteoarthritis Outcome Score (KOOS) subjective data were collected. A fasting blood sample (follicle stimulating hormone (FSH) and Tumor Necrosis Factor-α (TNF-α)), and urine catch (16α-hydroxyestrone and 2-hydroxyestrone) were collected. Gait analysis using an 8-camera motion analysis system assessed internal knee varus moment and foot progression angle. Pearson Product moments tested for associations between urinary 16α-hydroxyestrone and 2-hydroxyestrone, TNF-α, medial knee loading, and radiographic disease severity (Kellgren/Lawrence (K/L) radiographic score). Significant correlations were found within the hormonal biomarkers (r = 0.94, p p p = 0.31). No correlations were found for radiographic disease severity or TNF-α. The lack of association between hormonal and biomechanical variables could be due to large variability of the E2 metabolites seen in the menopause transition and the limited structural changes of initial staged knee OA.
文摘Background: Previous studies have demonstrated psychosocial and physical benefit from exercise for older men treated with androgen deprivation therapy (ADT) for prostate cancer (PCa). To date, different intervention delivery methods have not been assessed. This study compared the effect of group-based exercise (GBE) to personal training (PT) in men undergoing ADT for PCa. Methods: 13 participants (mean age = 68.2, SD = 7.2) were randomly assigned to GBE or PT for 8 weeks. Participants exercised for 60 minutes three times per week at a moderate-vigorous intensity. Results: 10 participants completed the intervention. At post-intervention, the PT group improved: fatigue, systolic BP, waist circumference, body fat percentage, and maximal leg strength;participants in the GBE group improved leg strength. At 8 weeks, maximal upper body strength in the PT group was greater than the GBE group. There were no adverse events associated with moderate-high intensity training in this population of older men. Conclusion: PT may be more efficacious than GBE in improving several physical fitness outcomes and fatigue in men with PCa who are androgen deprived. Due to the small sample size and attrition, these results require cautious interpretation and confirmation from adequately powered trials.
文摘Purpose:To quantify differences in nonlinear aspects of performance on a seated visual-motor tracking task between clinically asymptomatic males and females with and without a self-reported mild traumatic brain injury history.Methods:Seventy-three individuals with a self-reported concussion history(age:21.40±2.25 years,mean±SD)and 75 without completed the visual-motor tracking task(age:21.50±2.00 years).Participants pressed an index finger against a force sensor,tracing a line across a computer screen(visual-motor tracking).The produced signal's root-mean-square error(RMSE),sample entropy(SampEn,a measure of regularity),and average power(AvP)between 0 and 12 Hz were calculated.Results:Males with a history of 0 or 1 concussion had greater RMSE(worse performance)than females with 0(p<0.0001)and 1 concussion(p=0.052).Additionally,females with 2+concussions exhibited lower SampEn than females with no history(p=0.001)or a history of 1 concussion(p=0.026).Finally,females with 2+concussions had lower 8-12 Hz AvP than males with 2+concussions(p=0.031).Few differences were observed in the male participants.Conclusion:Females with a self-reported history of multiple concussions exhibited lower SampEn in the visual-motor tracking-task force output structure as compared to those with no reported history of concussion and their male counterparts.Lower SampEn and lower power between 8 and12 Hz indicated persistent impairment in visual processing and feed-forward or predictive motor control systems.
文摘Relative risk is a popular measure to compare risk of an outcome in the exposed group to the unexposed group. By applying the delta method and Central Limit Theorem, [1] derives two approximate confidence intervals for the relative risk, and [2] approximates the confidence interval for the relative risk via the likelihood ratio statistic. Both of these approximations require sample size to be large. In this paper, by adjusting the likelihood ratio statistic obtained by [2], a new method is proposed to obtain the confidence interval for the relative risk. Simulation results showed that the proposed method is extremely accurate even when the sample size is small.
文摘Training specificity is imperative for successful performance of the elite athlete.Virtual reality(VR)has been successfully applied to a broad range of training domains.However,to date there is little research investigating the use of VR for sport training.The purpose of this study was to address the question of whether virtual reality(VR)training can improve real world hockey shooting performance.Twenty four volunteers were recruited and randomly selected to complete the virtual training intervention or enter a control group with no training.Four primary types of data were collected:(1)participant’s experience with video games and hockey,(2)participant’s motivation toward video game use,(3)participant’s technical performance on real-world hockey,and(4)participant’s technical performance in virtual hockey.One-way multivariate analysis of variance(ANOVA)indicated that the intervention group demonstrated significantly more real-world hockey accuracy(F(1,24)=15.43,p<0.01,E.S.=0.56)while shooting on goal than their control group counterparts(intervention M accuracy=54.17%,SD=12.38,control M accuracy=46.76%,SD=13.45).One-way multivariate analysis of variance(MANOVA)repeated measures indicated significantly higher outcome scores on real-world accuracy(35.42%versus 54.17%;ES=1.52)and velocity(51.10 mph versus 65.50 mph;ES=0.86)of hockey shooting on goal.This research supports the idea that virtual training is an effective tool for increasing real-world hockey skill.
文摘This special issue highlights comprehensive reviews and researches on topics in fundamentally important areas of skeletal muscle physiology.1–6 The most important adaptive response of skeletal muscle to exercise,particularly resistant exercise,is increased protein synthesis,which is critical for promoting muscle hypertrophy and/or preventing atrophy.This process plays an essential role in promoting and maintaining skeletal muscle contractile and metabolic functions.
文摘Aim Portable devices that accurately detect the composition of expired gases and changes in VO_(2)open new possibilities in research methodology and accessibility.Purpose The purpose of this study was to compare the oxygen consumption(VO_(2))measurements of the VO_(2)Master Pro(VM)to the Cosmed K5(K5)during walking,jogging,and running in field and lab conditions.Methods Twelve proficient runners,with a current 10 k pace of≥11.29 km/h,performed 3 matched intervals at 3 different speeds(4.82,8.05,11.29 km/h)on a treadmill and on an outdoor track.An airflow test was also performed on both devices by pumping air through the devices using a 3 L syringe timed to a metronome at 15,25,and 35 beats/min.Results The VM did not report walking data for most participants.During treadmill running,there were significant differences in VO_(2)(47.86±3.94 vs.29.56±4.15 mL/kg/min),ventilation(V_(e))(71 vs.57 mL/min),and tidal volume(TV)(1.89 vs.1.56 L)between the K5 and VM respectively(P<0.05).Outdoor analysis also showed significant differences between devices in VO_(2),V_(e),and TV(P<0.05).The airflow test showed significant differences between the devices in V_(e)and TV(P<0.05).Conclusion These results suggest that there are significant discrepancies between the K5 and the VM,likely due to differ-ences in TV measurement.
文摘Mitochondria are essential energy-providing organelles that are required in the maintenance of healthy skeletal muscle.As such,the removal of damaged mitochondria,through mitophagy,is necessary to maintain mitochondrial quality.In aging muscle,mitochondrial content and function are often found to be reduced compared to young individuals.This occurs despite the fact that measures of mitophagy are elevated,suggesting that mitophagy is insufficiently high to remove all of the dysfunctional organelles in aging muscle.Recent evidence has shown that acute exercise promotes mitophagic signaling,leading to organelle degradation.This exercise-induced signaling is attenuated in aging muscle,suggesting that aging muscle loses its capacity for mitochondrial turnover in response to exercise.This contributes to the reduction in muscle health in elderly individuals.Chronic exercise training improves mitochondrial content and function,even in aging muscle,leading to reduced mitophagy signaling.Thus,exercise training should be prescribed for both young and elderly populations to pro-mote the maintenance of a healthy mitochondrial pool,through the stimulation of both organelle biogenesis and mitophagy.
基金supported by funding from the Canada Research Chairs Program and the Natural Sciences and Engineering Research Council of Canada.The authors wish to thank Ekso Bionics Holdings Inc.for providing the Ekso EVO passive shoulder exoskeleton.
文摘A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for high-level myoelectric-based hierarchical control is proposed.A Recurrent Neural Network(RNN)was trained using output data,initially obtained from offline optimization of the biomechatronic(human–robot)device and shifted by the prediction horizon.The input of the RNN consisted of interrupted sEMG signals(to mimic signal disconnections)and previous kinematic signals of the assistive system.The RNN with a 0.1-s prediction horizon could predict the control-oriented joint angle and assistive torque with 92%and 86.5%regression accuracy,respectively,for the test dataset.This proposed approach permits a fast,predictive,and direct estimation of control-oriented signals instead of an iterative process that optimizes assistive torque in the inverse dynamic simulation of a multibody human–robot system.Training with these interrupted input signals significantly improves the regression accuracy in the case of sEMG signal disconnection.This Robust Predictive Control-oriented Machine Learning(Robust-MuscleNET)model can support volitional high-level myoelectric-based control of biomechatronic devices,such as exoskeletons,prostheses,and assistive/resistive robots.Future work should study the application to prosthesis control as well as the repeatability of the high-level controller with electrode shift.The low-level hierarchical controller that manages the human–robot interaction,the assistance/resistance strategy,and the actuator coordination should also be studied.
基金supported by the Natural Sciences and Engineering Research Council of Canada (NSERC)the Canadian Research Chairs Program (CRC)+1 种基金the Mathematics for Information Technology and Complex Systems (MITACS)the support from the Canadian Network of Centers of Excellence, MITACS
文摘The surface glycoprotein hemagglutinin (HA) helps the influenza A virus to evade the host immune system by antigenic variation and is a major driving force for viral evolution. In this study, the selection pressure on HA of H5N1 influenza A virus was analyzed using bioinformatics algorithms. Most of the identified positive selection (PS) sites were found to be within or adjacent to epitope sites. Some of the identified PS sites are consistent with previous experimental studies, providing further support to the biological significance of our findings. The highest frequency of PS sites was observed in recent strains isolated during 2005–2007. Phylogenetic analysis was also conducted on HA sequences from various hosts. Viral drift is almost similar in both avian and human species with a progressive trend over the years. Our study reports new mutations in functional regions of HA that might provide markers for vaccine design or can be used to predict isolates of pandemic potential.
文摘Neisseria meningitidis is the agent of invasive meningococcal disease, including cerebral meningitis and septicemia. Because the diseases caused by different clonal groups (sequence types) have their own epidemiological characteristics, it is important to understand the differences among the genomes of the N. meningitidis clonal groups. To this end, a novel interpretation of a structural dot plot of genomes was devised and applied; exact nucleotide matches between the genomes of N. meningitidis serogroup A strain Z2491 and serogroup B strain MC58 were identified, leading to the specification of various structural regions. Known and putative virulence genes for each N. meningitidis strain were then classified into these regions. We found that virulence genes of MC58 tend more to the translocated regions (chromosomal segments in new sequence contexts) than do those of Z2491, nota- bly tending towards the interface between one of the translocated regions and the collinear region. Within the collinear region, virulence genes tend to occur within 16 kb of gaps in the exact matches. Verification of these tendencies using genes clustered in the cps locus was sufficiently supportive to suggest that these tendencies can be used to focus the search for and understanding of virulence genes and mechanisms of pathogenicity in these two organisms.
文摘Introduction The bench press is commonly used to measure upper-body strength.While much emphasis has been placed on the upper-body,little is known about how the lower-body can play a role in bench press performance.Leg-drive is a technique that includes flexing the knee so the feet line up posterior to the knee joint,while simultaneously contracting the knee extensors isometrically during the lift.The purpose of this study was to compare strength characteristics of lifters in a standard bench press versus a leg-drive bench press over the course of 5-weeks of training.Methods Twenty-three recreationally active males(age:22.4±2.1 years,height:175.0±5.9 cm,mass:78.4±9.5 kg)were randomized into a standard bench or leg-drive bench press group.Participants performed four sets to failure,two times per week for five weeks.Variables of interests were training volume and 1-repetition maximum(1RM)strength.For training volume,a 2×5(group×week)repeated measures analysis of variance(RMANOVA)was used.For the 1RM’s,a 2×2×2(group×press type×time)RMANOVA was used.A priori alpha levels were set to 0.05.Results Over time,both groups showed an approximate 6%increase in 1RM strength.Training volume for week 4 was 5.6%less than week 5,but was not different from weeks 1 through 3.No between-group differences were observed for 1RM strength or training volume.Conclusion This results of this work indicates that 5 weeks of leg-drive training is effective in increasing 1RM strength,but was not more effective than standard bench press training.Practically,lifters should choose either lifting style based on personal preference.
基金The work was funded by Natural Sciences and Engineering Research Council(NSERC)and Canadian Institutes of Health Research(CIHR)grants to D.A.H.A.N.O.is the recipient of an NSERC CGS-D.D.A.H.is the recipient of a Canada Research Chair in Cell Physiology.
文摘Mitochondria are vital organelles that provide energy for muscle function.When these organelles become dysfunctional,they produce less energy as well as excessive levels of reactive oxygen species which can trigger muscle atrophy,weakness and loss of endurance.In this review,molecular evidence is provided to show that exercise serves as a useful therapeutic countermeasure to overcome mitochondrial dysfunction,even when key regulators of organelle biogenesis are absent.These findings illustrate the complexity and compensatory nature of exercise-induced molecular signaling to transcription,as well as to post-transcriptional events within the mitochondrial synthesis and degradation(i.e.turnover)pathways.Beginning with the first bout of contractile activity,exercise exerts a medicinal effect to improve mitochondrial health and whole muscle function.
