Objective:To study the frequency of electrical stimulation affect the atrophy recovery of mouse soleus muscle.Method:Sixty mice,30 of them were randomly divided into blank control group (Con) and atrophy model group (Atro) and validated this model after 1 week.The other 30 mice were randomly divided into three groups:the natural recovery group (Rec),the exercise intervention group (Exer),the electroacupuncture intervention group (Elec) after making them atrophy.Atrophy model group were plaster fixed one week.Natural recovery group was natural fed two weeks after removing the plaster.Exercise intervention group runs 1 hour at 16m/min speed two weeks.EA intervention group were stimulated 15min daily for 2 weeks on hind limb,with pulse duration 0.35ms,frequency 50Hz,for 2 weeks.Frozen sections and Immunofluorescence were used to measure the cross-sectional area of muscle fibers.ATPase staining was used to detect the muscle fiber type changing,and Western Blot to detect soleus muscle Troponin I-SS (TNNI1) and Troponin I-FS (TNNI2) protein expression.Result:The soleus muscle in Atro group showed significant change in cross-sectional area and wet weight compared with Con group(P＜0.01),The expression of TNNI1 and TNNI2 protein was also significantly different from that of Con group (P＜0.05).Compared with the Rec group,the cross-sectional area of slow muscle and fast muscle in the Exer and Elec groups significantly increased (P＜0.05),TNNI1 protein expression significant ly increased (P＜0.01),TNNI2 protein was no significant difference detected(P＞0.05).Conclusion:The middle low frequency electroacupuncture intervention can effectively increase the cross-sectional area of muscle fibers,in particular,increase the TNNI1 and TNNI2 protein expression of slow muscle fibers.It is as effective as exercise intervention to promote recovery of disuse muscular atrophy.

Objective To explore the effect of age,walking speed and the morphological growth of lower limbs on 4～6 years old children's gait,so as to provide theoretical references for children's gait assessment and the design of a walker robot.Methods Totally one hundred and fifty-seven children ranging in age from 4 to 6 were selected as subjects in this research.Gait parameters were acquired by the 3D shooting technique,while the morphological indexes of the lower extremity,including the length A of the lower extremity,calf length,thigh circumference,pelvic width,width between two greater trochanters,foot length,foot girth and foot width,were measured.The differences of gait parameters among children of different ages and sexes were compared using the variance analysis.The step regression analysis was carried out to study the relationship between the walking speed and other gait parameters.The relationship between children's gait and morphology was analyzed using the canonical correlation analysis.Results The six-year-old children's gait cycle,step length and walking speed were significantly higher than those of four-and five-year-old children(P＜0.05).The swing phase percentage of six-year-old children was significantly higher than that of four-year-old ones(P＜0.05).The support percentage of six-year-old children was significantly lower than that of the four-year-old(P＜0.05).With the increase of the walking speed,young children's step length,cadence and percentage of the swing phase increased linearly.And the gait cycle,percentage of double support phase and percentage of the support phase decreased linearly with the increase of the walking speed.There was significant correlation between the lower extremity length A,calf length,width between two greater trochanters and step length for the children aged from four to six.Conclusion For children aged 4 to 6 years,the step length,walking speed and gait cycle increase continuously with the increment of age,whereas the cadence and percentage of the support phase decrease with the increment of age.The step speed is significantly correlated with other gait parameters such as the step length,cadence and gait cycle.The length of lower extremities,calf length and width between two greater trochanters are the main factors which affect the step length.

Objective :To explore influence of cardiopulmonary endurance improvement on blood lipid ,aiming at pro‐viding reference for reducing morbidity of cardiovascular Dis in middle‐aged and aged people in China .Methods :Databases including China National Knowledge Infrastructure (CNKI ) , Wanfang , VIP , Bailianyun etc .were searched .Literature were screened according to inclusion and exclusion criteria ,while article quality assessment and data extraction were performed ,and RevMan5. 3 software was used to perform Meta‐analysis.Results :Meta‐analy‐sis indicated that exercise‐improving cardiopulmonary endurance in middle‐aged and aged people can significantly re‐duce levels of triglyceride [TG ,combined effect size :－0. 42 ,95% CI (－0.60 ,－0.24 ) , P＝ 0. 001 ] and low density lipoprotein cholesterol [(LDL‐C ,combined effect size :－0.44 ,95% CI (－0.85 , 0. 03) ,P＝0.04] ,while it had no significant influence on levels of total cholesterol [TC ,combined effect size :－0.71 , 95% CI (－1. 46 , 0.03) , P＝0. 06] and high density lipoprotein cholesterol [HDL‐C ,combined effect size :0. 20 , 95% CI (－0. 09 , 0.50) , P＝0.18].Subgroup analysis indicated that power bicycle and type K 4b2 cardiopulmonary endurance meas‐urement method of COSME company (K4b2 method) possessed significant influence on levels of TC and TG ;Bruce treadmill testing system possessed significant influence on HDL‐C level ;Bruce treadmill test and K4b2 method pos‐sessed significant influence on LDL‐C level .Conclusion :Exercise‐improving cardiopulmonary endurance in middle‐aged and aged people can effectively reduce levels of triglyceride and low density lipoprotein cholesterol .

Objective To identify the differences of three-dimensional knee kinematics of unilateral anterior cruciate ligament (ACL) deficient patients with and without the meniscus injury.Methods A total of 39 subjects including unilateral isolate ACL-deficient patients (ACL group,n=13),ACL deficient patients combined with meniscus tear (ACL+M group,n=13) and healthy controls (C group,n=13) participated in this study.In the gait analysis,three-dimensional knee kinematic and kinetic parameters were collected synchronously and compared.Results The peak knee flexion angles were greater in the ACL+M group and C group compared with the ACL group (P=0.001,P=0.001),with no significant differences between the former two groups (P=0.847).Lower first peak vertical ground reaction force,peak posterior ground reaction force,sagittal plane knee excursions and peak knee extension moment were found in ACL-injured side compared with the contralateral side (P=0.001,P＜0.001,P=0.006,P=0.001).Greater peak knee abduction moment was found in group ACL+M compared with both the ACL and C groups (P=0.045,P=0.014).However,no significant difference was observed between the ACL group and C group in peak knee abduction moment (P=0.616).Conclusions The altered loading in unilateral ACL deficient patients can lead to lower ground reaction force in injured knee and greater ground reaction force in the contralateral side,which may increase the risk of developing knee osteoarthritis.The greater internal knee abduction moment in ACL deficient patients combined with meniscus injury may be a risking factor for the knee osteoarthritis.

Objective To investigate the effect of acute exercises of different intensities on the "browning" of epididymal white adipose tissue(WAT) in rats.Methods Thirty Sprague-Dawley male rats were randomly divided into a control group(C,n=6) and an exercises group(E,n=24).Rats in group E were further randomly divided into a moderate intensity exercise (EM,n=12,V=15 m/min) group and a high intensity intermittent exercise(EH,n=12,V=35 m/min,6min's exercises followed by 5 min's rest,repeating 3 times) group.Right after and 6 hours after the acute exercises,the epididymal WAT was taken,and the fibronectin type Ⅲ domain-containing 5 protein(FNDC5) and the uncoupling protein 1(UCP-1) mRNA were detected using RT-qPCR,while the level of FNDC5 and UCP-1 protein was evaluated using Western Blotting.Results Right after the acute exercises,compared with group C,the level of FNDC5 mRNA in group EH increased significantly (P＜0.01),while that of UCP-1 mRNA in group E decreased immediately(P＜0.05) but increased significantly six hours later(P＜0.05).Compared with group C,the level of FNDC5 in groups EM and EH tended to rise,and that of group EM increased significantly(P＜0.05).Compared with group C,the level of UCP-1 in group EM and EH had the tendency to rise,and it increased significantly immediately after exercises in group EH (P＜0.05).Conclusion The acute exercise at different intensities can promote the level of FNDC5 and UCP-1 in epididymal white adipose tissue,"browning" and heat production from fat issues.The level of UCP-1 mRNA increased significantly at 6 hours after exercises,while that of FNDC5 mRNA increased most immediately after the high-intensity intermittent exercises.

BACKGROUND:Collagen is the most abundant extracellular matrix component,which is closely related to the structure and function of the extracellular matrix of skeletal muscle,but the effect and mechanism of recombinant human collagen(rhC)produced by bioengineering technology on the extracellular matrix of skeletal muscle are unclear. OBJECTIVE:To investigate the effect of rhC supplementation on the remodeling of skeletal muscle extracellular matrix after eccentric exercise,thereby revealing the possible mechanism by which rhC improves the injury of skeletal muscle extracellular matrix and promote the recovery after exercise. METHODS:A total of 104 healthy male C57 mice aged 8 weeks old were randomly divided into control group(normal saline),low-dose rhC group(0.2 g/kg),medium-dose rhC group(1.0 g/kg),and high-dose rhC group(2.0 g/kg).Two mice in each group were selected after continuous 7 days of intragastric intervention,and organs were dissected for hematoxylin-eosin staining to determine inflammatory infiltrates.On the 8th day,the remaining mice were subjected to eccentric exercise.The structural changes of the skeletal muscle extracellular matrix were observed under scanning electron microscopy immediately(0),24,48,and 96 hours after eccentric exercise.Meanwhile,grip strength,creatine kinase activity,and protein levels of matrix metalloproteinases 2,9,14 and tissue inhibitor of metalloproteinase-2 in skeletal muscle were detected by western blot assay. RESULTS AND CONCLUSION:Hematoxylin-eosin staining results indicated that short-term rhC supplementation showed no significant effects on the morphology of the heart,liver,spleen and kidney.After one-time eccentric exercise,the recovery rate of grip strength in the medium-and high-dose rhC groups was significantly increased(P＜0.01).The trend of creatine kinase changes was consistent in all groups and there was no significant difference between groups.The recovery process of the extracellular matrix in the low-dose rhC group was faster than that in the control group,and the muscle tract membrane in the medium-and high-dose rhC groups was more complete.The protein level of matrix metalloproteinase 9 in the high-dose rhC group was significantly decreased(P＜0.05).The protein levels of matrix metalloproteinase 14 in the medium-and high-dose rhC groups were significantly decreased(P＜0.05).The protein levels of matrix metalloproteinase 2 in the medium-and high-dose rhC groups were significantly decreased(P＜0.05).Tissue inhibitor of metalloproteinase-2 protein levels in the medium-and high-dose rhC groups were significantly increased(P＜0.05).The ratio of matrix metalloproteinase 2 to tissue inhibitor of metalloproteinase-2 in each rhC group was significantly decreased(P＜0.05).To conclude,pre-supplementation of 1.0 and 2.0 g/kg rhC for 7 days can inhibit extracellular matrix degradation in skeletal muscle after exercise by modulating matrix metalloproteinases and matrix metalloproteinase inhibitors,thereby promoting recovery of skeletal muscle strength in mice.

BACKGROUND:In recent years,studies have shown that obesity is closely related to chronic inflammation.Due to excessive energy intake,inflammatory macrophage infiltration and inflammatory response occur in visceral adipose tissue,which is crucial for the regulation of adipose tissue fibrosis. OBJECTIVE:To summarize the molecular mechanism of inflammation-related signals involved in the regulation of adipose tissue fibrosis and to provide reference for the treatment of adipose tissue fibrosis and related metabolic diseases through anti-inflammatory pathways. METHODS:Relevant documents were retrieved from CNKI and PubMed,and the Chinese and English search words were"inflammation,inflammatory factors,inflammatory signals,lip fibrosis,adipose fibrosis,adipose tissue fibrosis"respectively.The search period was from January 2003 to December 2022.Finally,52 documents meeting the criteria were included for review. RESULTS AND CONCLUSION:During obesity,visceral adipose tissue expands through adipocyte proliferation and hypertrophy to store excess energy,and defects caused by remodeling or functional changes mainly include impaired angiogenesis,adipocyte apoptosis promoted by white adipose tissue hypoxia,macrophage infiltration,and adipocyte fibrosis.Adipose tissue fibrosis has adverse effects on the natural growth of adipose cells.The factors that trigger chronic inflammation of adipose tissue include a variety of signal stimuli,such as adipocyte death caused by hypoxia,mechanical signal transduction caused by extracellular matrix remodeling and lipogenic factor imbalance.Inflammatory factors such as interleukin-1β,tumor necrosis factor-α,C-type lectins and adiponectin secreted by adipocytes and other inflammatory signaling pathways such as nuclear factor-κB,transforming growth factor-β/Smad and MAPK jointly regulate the process of adipose tissue fibrosis.

Objective To compare the differences in gait characteristics and stability of women walking with or without sports bra.Methods Twelve women with C cup breast were required to walk on the treadmill (at the speed of 6 krn/h) with and without sports bras,respectively.Their gait parameters were collected by using Qualisys Track Manager high-speed infrared motion capture system.Results Compared with the bare-breasted condition,the maximum and minimum angles of the upper trunk were significantly smaller when subjects wearing the sports bra,the range of trunk flexion angles and trunk torsion angles were also relatively smaller,and the standard deviation of hip flexion angles during 10 gait cycles was obviously smaller.However,no differences were found in stride frequency between two breast support conditions.Conclusions Different breast support conditions have a significant influence on the upper trunk angle,trunk flexion angle and trunk torsion angle.Walking without bra will increase the range of trunk angle and deteriorate the walking stability.The stride frequencies under different breast support conditions have individual differences.