In this letter, a comparison between three types （two linear and one nonlinear） of models of skeletal muscle stiffness is shown. Results are compared with experimental data for biceps brachii in the case of muscle s...In this letter, a comparison between three types （two linear and one nonlinear） of models of skeletal muscle stiffness is shown. Results are compared with experimental data for biceps brachii in the case of muscle stretching and with the Hill equation for a biological muscle. It is shown that results for nonlinear stiffness model in case of length-force relationship fits to the experimental data.展开更多
Background:Due to its high relevance in sports and rehabilitation,the exploration of interventions to further optimize flexibility becomes paramount.While stretching might be the most common way to enhance range of mo...Background:Due to its high relevance in sports and rehabilitation,the exploration of interventions to further optimize flexibility becomes paramount.While stretching might be the most common way to enhance range of motion,these increases could be optimized by imposing an additional activation of the muscle,such as mechanical vibratory stimulation.While several original articles provide promising findings,contradictory results on flexibility and underlying mechanisms(e.g.,stiffness),reasonable effect size(ES)pooling remains scarce.With this work we systematically reviewed the available literature to explore the possibility of potentiating flexibility,stiffness,and passive torque adaptations by superimposing mechanical vibration stimulation.Methods:A systematic search of 4 databases(Web of Science,MEDLINE,Scopus,and Cochrane Public Library)was conducted until December2023 to identify studies comparing mechanical vibratory interventions with passive controls or the same intervention without vibration(sham)on range of motion and passive muscle stiffness in acute(immediate effects after single session)and chronic conditions(multiple sessions over a period of time).ES pooling was conducted using robust variance estimation via R to account for multiple study outcomes.Potential moderators of effects were analyzed using meta regression.Results:Overall,65 studies(acute:1162 participants,chronic:788 participants)were included.There was moderate certainty of evidence for acute flexibility(ES=0.71,p<0.001)and stiffness(ES=-0.89,p=0.006)effects of mechanical vibration treatments vs.passive controls without meaningful results against the sham condition(flexibility:ES=0.20,p<0.001;stiffness:ES=-0.19,p=0.076).Similarly,moderate certainty of evidence was found for chronic vibration effects on flexibility(control:ES=0.64,p=0.043;sham:ES=0.65,p<0.001).Lack of studies and large outcome heterogeneity prevented ES pooling for underlying mechanisms.Conclusion:Vibration improved flexibility in acute and chronic interventions compared to the stand-alone intervention,which can possibly be attributed to an accumulated mechanical stimulus through vibration.However,studies on biological mechanisms are needed to explain flexibility and stiffness effects in response to specific vibration modalities and timing.展开更多
BACKGROUND Real-time shear wave elastography(SWE)is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time.This advanced ultrasound-based method provides ...BACKGROUND Real-time shear wave elastography(SWE)is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time.This advanced ultrasound-based method provides quantitative information regarding tissue elasticity,offering valuable insights into the mechanical properties of biological tissues.However,the application of real-time SWE in the musculoskeletal system and sports medicine has not been extensively studied.AIM To explore the practical value of real-time SWE for assessing Achilles tendon hardness in older adults.METHODS A total of 60 participants were enrolled in the present study,and differences in the elastic moduli of the bilateral Achilles tendons were compared among the following categories:(1)Age:55-60,60-65,and 65-70-years-old;(2)Sex:Male and female;(3)Laterality:Left and right sides;(4)Tendon state:Relaxed and tense state;and(5)Tendon segment:Proximal,middle,and distal.RESULTS There were no significant differences in the elastic moduli of the bilateral Achilles tendons when comparing by age or sex(P>0.05).There were,however,significant differences when comparing by tendon side,state,or segment(P<0.05).CONCLUSION Real-time SWE plays a significant role compared to other examination methods in the evaluation of Achilles tendon hardness in older adults.展开更多
Background： Glenohumeral internal rotation deficit （GIRD） is a risk factor for shoulder and elbow injury in baseball players. Although this evidence forms a basis for recommending stretching, clinical measures of i...Background： Glenohumeral internal rotation deficit （GIRD） is a risk factor for shoulder and elbow injury in baseball players. Although this evidence forms a basis for recommending stretching, clinical measures of internal rotation range of motion （ROM） do not differentiate if GIRD is due to muscular, capsuloligamentous, or osseous factors. Understanding the contributions of these structures to GIRD is important for the development of targeted interventions. We hypothesize that the osseous component will have the greatest relative contribution to GIRD, followed by muscle stiffness and posterior capsule thickness. Methods： Internal rotation ROM, muscle stiffness （teres minor, infraspinatus, and posterior deltoid）, posterior capsule thickness, and humeral retrotorsion were evaluated on 156 baseball players. A side-to-side difference was calculated for each variable. Variables were entered into a multivariable linear regression to determine the significant predictors of GIRD. Results： The regression model was statistically significant （R2 = 0.134, F（1, 156） = 24.0, p 〈 0.01） with only humeral retrotorsion difference remaining as a significant predictor （β = -0.243, t156 = -4.9, p 〈 0.01）. A greater humeral retrotorsion side-to-side difference was associated with more GIRD. Conclusion： Humeral retrotorsion accounted for 13.3% of the variance in GIRD. The stiffness of the superficial shoulder muscles and capsular thickness, as measured in this study, were not predictors of GIRD. Factors not assessed in this study, such as deeper muscle stiffness, capsule/ ligament laxity, and neuromuscular regulation of muscle stiffness may also contribute to GIRD. Since it is the largest contributor to GIRD, causes of changes in humeral retrotorsion need to be identified. The osseous component only accounted for 13.3% of the variance in GIRD, indicating a large contribution from soft tissues factors that were not addressed in this study. These factors need to be identified to develop evidence-based evaluations and intervention programs to decrease the risk of injury in baseball players.展开更多
基金supported by"Master Programme"of the Foundation for Polish Science
文摘In this letter, a comparison between three types （two linear and one nonlinear） of models of skeletal muscle stiffness is shown. Results are compared with experimental data for biceps brachii in the case of muscle stretching and with the Hill equation for a biological muscle. It is shown that results for nonlinear stiffness model in case of length-force relationship fits to the experimental data.
文摘Background:Due to its high relevance in sports and rehabilitation,the exploration of interventions to further optimize flexibility becomes paramount.While stretching might be the most common way to enhance range of motion,these increases could be optimized by imposing an additional activation of the muscle,such as mechanical vibratory stimulation.While several original articles provide promising findings,contradictory results on flexibility and underlying mechanisms(e.g.,stiffness),reasonable effect size(ES)pooling remains scarce.With this work we systematically reviewed the available literature to explore the possibility of potentiating flexibility,stiffness,and passive torque adaptations by superimposing mechanical vibration stimulation.Methods:A systematic search of 4 databases(Web of Science,MEDLINE,Scopus,and Cochrane Public Library)was conducted until December2023 to identify studies comparing mechanical vibratory interventions with passive controls or the same intervention without vibration(sham)on range of motion and passive muscle stiffness in acute(immediate effects after single session)and chronic conditions(multiple sessions over a period of time).ES pooling was conducted using robust variance estimation via R to account for multiple study outcomes.Potential moderators of effects were analyzed using meta regression.Results:Overall,65 studies(acute:1162 participants,chronic:788 participants)were included.There was moderate certainty of evidence for acute flexibility(ES=0.71,p<0.001)and stiffness(ES=-0.89,p=0.006)effects of mechanical vibration treatments vs.passive controls without meaningful results against the sham condition(flexibility:ES=0.20,p<0.001;stiffness:ES=-0.19,p=0.076).Similarly,moderate certainty of evidence was found for chronic vibration effects on flexibility(control:ES=0.64,p=0.043;sham:ES=0.65,p<0.001).Lack of studies and large outcome heterogeneity prevented ES pooling for underlying mechanisms.Conclusion:Vibration improved flexibility in acute and chronic interventions compared to the stand-alone intervention,which can possibly be attributed to an accumulated mechanical stimulus through vibration.However,studies on biological mechanisms are needed to explain flexibility and stiffness effects in response to specific vibration modalities and timing.
基金Supported by Sichuan Orthopaedic Hospital Research Project,No.2019MS02.
文摘BACKGROUND Real-time shear wave elastography(SWE)is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time.This advanced ultrasound-based method provides quantitative information regarding tissue elasticity,offering valuable insights into the mechanical properties of biological tissues.However,the application of real-time SWE in the musculoskeletal system and sports medicine has not been extensively studied.AIM To explore the practical value of real-time SWE for assessing Achilles tendon hardness in older adults.METHODS A total of 60 participants were enrolled in the present study,and differences in the elastic moduli of the bilateral Achilles tendons were compared among the following categories:(1)Age:55-60,60-65,and 65-70-years-old;(2)Sex:Male and female;(3)Laterality:Left and right sides;(4)Tendon state:Relaxed and tense state;and(5)Tendon segment:Proximal,middle,and distal.RESULTS There were no significant differences in the elastic moduli of the bilateral Achilles tendons when comparing by age or sex(P>0.05).There were,however,significant differences when comparing by tendon side,state,or segment(P<0.05).CONCLUSION Real-time SWE plays a significant role compared to other examination methods in the evaluation of Achilles tendon hardness in older adults.
文摘Background： Glenohumeral internal rotation deficit （GIRD） is a risk factor for shoulder and elbow injury in baseball players. Although this evidence forms a basis for recommending stretching, clinical measures of internal rotation range of motion （ROM） do not differentiate if GIRD is due to muscular, capsuloligamentous, or osseous factors. Understanding the contributions of these structures to GIRD is important for the development of targeted interventions. We hypothesize that the osseous component will have the greatest relative contribution to GIRD, followed by muscle stiffness and posterior capsule thickness. Methods： Internal rotation ROM, muscle stiffness （teres minor, infraspinatus, and posterior deltoid）, posterior capsule thickness, and humeral retrotorsion were evaluated on 156 baseball players. A side-to-side difference was calculated for each variable. Variables were entered into a multivariable linear regression to determine the significant predictors of GIRD. Results： The regression model was statistically significant （R2 = 0.134, F（1, 156） = 24.0, p 〈 0.01） with only humeral retrotorsion difference remaining as a significant predictor （β = -0.243, t156 = -4.9, p 〈 0.01）. A greater humeral retrotorsion side-to-side difference was associated with more GIRD. Conclusion： Humeral retrotorsion accounted for 13.3% of the variance in GIRD. The stiffness of the superficial shoulder muscles and capsular thickness, as measured in this study, were not predictors of GIRD. Factors not assessed in this study, such as deeper muscle stiffness, capsule/ ligament laxity, and neuromuscular regulation of muscle stiffness may also contribute to GIRD. Since it is the largest contributor to GIRD, causes of changes in humeral retrotorsion need to be identified. The osseous component only accounted for 13.3% of the variance in GIRD, indicating a large contribution from soft tissues factors that were not addressed in this study. These factors need to be identified to develop evidence-based evaluations and intervention programs to decrease the risk of injury in baseball players.
