Subject-specific spinal musculoskeletal modeling can help understand the spinal loading mechanism during human locomotion.However,existing literature lacks methods to identify the maximum isometric strength of individ...Subject-specific spinal musculoskeletal modeling can help understand the spinal loading mechanism during human locomotion.However,existing literature lacks methods to identify the maximum isometric strength of individual spinal muscles.In this study,a muscle strength identification method combining isokinetic testing and musculoskeletal simulations was proposed,and the influence of muscle synergy and intra-abdominal pressure(IAP)on identified spinal muscle strength was further discussed.A multibody dynamic model of the spinal musculoskeletal system was established and controlled by a feedback controller.Muscle strength parameters were adjusted based on the measured isokinetic moments,and muscle synergy vectors and the IAP piston model were further introduced.The results of five healthy subjects showed that the proposed method successfully identified the subject-specific spinal flexor/extensor strength.Considering the synergistic activations of antagonist muscles improved the correlation between the simulated and measured spinal moments,and the introduction of IAP slightly increased the identified spinal extensor strength.The established method is beneficial for understanding spinal loading distributions for athletes and patients with sarcopenia.展开更多
BACKGROUND： Lower body strength is considered to be a critical component towards successful exercise performance in football players. The aim of this study was to describe the peak isokinetic torque of the knee in pr...BACKGROUND： Lower body strength is considered to be a critical component towards successful exercise performance in football players. The aim of this study was to describe the peak isokinetic torque of the knee in professional football players of different League divisions in Cyprus and assess bilateral and unilateral asymmetries of strength. METHODS： Four hundred and twenty-nine professional male football players participated in this study （Division 1, n = 245 and Division 2, n = 184）. The isokinetic muscle function of the knee was measured using the Humac Norm Testing and Rehabilitation system （CSMi Medical ＆ Solution, USA）. Measurements were collected at angle speeds of 60 °/sec and 300 °/sec, for 3 and 25- repetitions respectively. RESULTS： At both angle speeds, peak isokinetic torque of the knee joint was significantly higher in the right and left knees of players in Division 1 （D1） compared to those competing in Division 2 （D2）. At both testing speeds, peak flexor torque of the left hamstrings was significantly higher in players participating in Division 1 compared to those competing in Division 2. The right hamstrings yielded similar results, except at 60 °/sec, where no difference was found between the groups. CONCLUSION： This study provides valuable data regarding the forces produced by the lower body of football players participating in D1 and D2 in Cyprus, whilst also disclosing there to be no bilateral imbalances or abnormal H/Q ratios. The results of this study may provide pertinent information that can be used by the coaching staff for training and recruiting purposes.展开更多
Purpose To determine the amount of familiarization sessions required by breast cancer survivors to achieve a reliable meas-urement of muscle function assessed using isokinetic dynamometry.Methods Twenty-six breast can...Purpose To determine the amount of familiarization sessions required by breast cancer survivors to achieve a reliable meas-urement of muscle function assessed using isokinetic dynamometry.Methods Twenty-six breast cancer survivors performed three isokinetic knee extension tests separated by,at least,48 h.The isokinetic testing protocol included one warm-up set of 10 submaximal knee extensions at 120°/s,followed by two sets of four maximal knee extensions at 60°/s,with 2-min rest interval between sets.Peak torque(PT),time to peak torque(TPT),angle of peak torque(APT),and average power(AP)of each trial was used for the assessment of testing reliability.Percentage change in the mean,typical error,coefficient of variation and intraclass correlation coefficients(ICC2.1)were calculated to determine test-retest reliability.Results For PT,change in mean was lower between trials 2 and 3 than between trials 1 and 2(4.18% and 13.18%,respec-tively),and ICC was greater between trials 2 and 3 than between trials 1 and 2(0.962 and 0.818,respectively).For TPT and APT,ICC was clinically acceptable only between trials 2 and 3(0.757 and 0.803,respectively).For AP,change in mean was clinically acceptable between trials 2 and 3(9.84%),while ICC met acceptable reliability between both,trials 1 and 2 and,trials 2 and 3(0.756 and 0.891,respectively).Conclusion At least one familiarization session is adequate to achieve reliable measurements of muscle function using isokinetic dynamometry,while avoiding the impact of learning effect of the measurements in breast cancer survivors.展开更多
基金supported in part by the National Natural Science Foundation of China(grant numbers 12132009,12102035,and 12125201)Beijing Natural Science Foundation(grant number L212008).
文摘Subject-specific spinal musculoskeletal modeling can help understand the spinal loading mechanism during human locomotion.However,existing literature lacks methods to identify the maximum isometric strength of individual spinal muscles.In this study,a muscle strength identification method combining isokinetic testing and musculoskeletal simulations was proposed,and the influence of muscle synergy and intra-abdominal pressure(IAP)on identified spinal muscle strength was further discussed.A multibody dynamic model of the spinal musculoskeletal system was established and controlled by a feedback controller.Muscle strength parameters were adjusted based on the measured isokinetic moments,and muscle synergy vectors and the IAP piston model were further introduced.The results of five healthy subjects showed that the proposed method successfully identified the subject-specific spinal flexor/extensor strength.Considering the synergistic activations of antagonist muscles improved the correlation between the simulated and measured spinal moments,and the introduction of IAP slightly increased the identified spinal extensor strength.The established method is beneficial for understanding spinal loading distributions for athletes and patients with sarcopenia.
文摘BACKGROUND： Lower body strength is considered to be a critical component towards successful exercise performance in football players. The aim of this study was to describe the peak isokinetic torque of the knee in professional football players of different League divisions in Cyprus and assess bilateral and unilateral asymmetries of strength. METHODS： Four hundred and twenty-nine professional male football players participated in this study （Division 1, n = 245 and Division 2, n = 184）. The isokinetic muscle function of the knee was measured using the Humac Norm Testing and Rehabilitation system （CSMi Medical ＆ Solution, USA）. Measurements were collected at angle speeds of 60 °/sec and 300 °/sec, for 3 and 25- repetitions respectively. RESULTS： At both angle speeds, peak isokinetic torque of the knee joint was significantly higher in the right and left knees of players in Division 1 （D1） compared to those competing in Division 2 （D2）. At both testing speeds, peak flexor torque of the left hamstrings was significantly higher in players participating in Division 1 compared to those competing in Division 2. The right hamstrings yielded similar results, except at 60 °/sec, where no difference was found between the groups. CONCLUSION： This study provides valuable data regarding the forces produced by the lower body of football players participating in D1 and D2 in Cyprus, whilst also disclosing there to be no bilateral imbalances or abnormal H/Q ratios. The results of this study may provide pertinent information that can be used by the coaching staff for training and recruiting purposes.
文摘Purpose To determine the amount of familiarization sessions required by breast cancer survivors to achieve a reliable meas-urement of muscle function assessed using isokinetic dynamometry.Methods Twenty-six breast cancer survivors performed three isokinetic knee extension tests separated by,at least,48 h.The isokinetic testing protocol included one warm-up set of 10 submaximal knee extensions at 120°/s,followed by two sets of four maximal knee extensions at 60°/s,with 2-min rest interval between sets.Peak torque(PT),time to peak torque(TPT),angle of peak torque(APT),and average power(AP)of each trial was used for the assessment of testing reliability.Percentage change in the mean,typical error,coefficient of variation and intraclass correlation coefficients(ICC2.1)were calculated to determine test-retest reliability.Results For PT,change in mean was lower between trials 2 and 3 than between trials 1 and 2(4.18% and 13.18%,respec-tively),and ICC was greater between trials 2 and 3 than between trials 1 and 2(0.962 and 0.818,respectively).For TPT and APT,ICC was clinically acceptable only between trials 2 and 3(0.757 and 0.803,respectively).For AP,change in mean was clinically acceptable between trials 2 and 3(9.84%),while ICC met acceptable reliability between both,trials 1 and 2 and,trials 2 and 3(0.756 and 0.891,respectively).Conclusion At least one familiarization session is adequate to achieve reliable measurements of muscle function using isokinetic dynamometry,while avoiding the impact of learning effect of the measurements in breast cancer survivors.
