BACKGROUND:The maximum muscle strength is typically used for evaluating the recovery of muscle function after anterior cruciate ligament reconstruction.Recent studies have suggested that neuromuscular function should also be considered,such as rate of force development,which measures the slope of the force time curve at different time intervals under conditions of isometric muscle contraction. OBJECTIVE:To elaborate on the current research status and shortcomings of muscle isometric rate of force development in patients undergoing anterior cruciate ligament reconstruction surgery,and analyze the degree of defects in quadriceps femoris and hamstring isometric rate of force development at different times after surgery;to analyze the effect of isometric rate of force development on postoperative functional performance,thereby providing important information for optimizing postoperative rehabilitation following anterior cruciate ligament reconstruction,reducing secondary injury to patients,and reducing the incidence of knee osteoarthritis. METHODS:Literature retrieval of CNKI,VIP,WanFang and PubMed was performed using"anterior cruciate ligament,rate of force development"as Chinese search terms and"anterior cruciate ligament,rate of force development,rate of torque development"as English search terms.Finally,69 articles were included according to inclusion and exclusion criteria. RESULTS AND CONCLUSION:Most studies have found defects in bilateral muscle isometric rate of force development in patients undergoing anterior cruciate ligament reconstruction within 6 months.Early isometric rate of force development of the bilateral hamstring muscles(i.e.the slope of the force time curve at any time interval during muscle contraction of 100 ms)showed significant improvement after 6 months.However,long-term defects in early isometric rate of force development of the bilateral quadriceps indicate long-term damage to the neuromuscular function of the quadriceps after surgery.There is limited research on late isometric rate of force development(the slope of the force time curve at any time interval after 100 ms of muscle contraction),and conclusions cannot be drawn.Regarding landing exercises(jumping to the ground,lateral cutting,etc.)and daily activities(walking,running),early isometric rate of force development of the quadriceps is more correlated with isometric peak torque.Abnormal biomechanical changes during exercise are considered an important risk factor for secondary injury and traumatic knee osteoarthritis in patients.Actively improving early isometric rate of force development of the quadriceps may reduce the incidence of secondary injury and traumatic knee osteoarthritis.Currently,there is limited evidence to suggest that whole-body vibration training can improve early isometric rate of force development of the quadriceps femoris in patients undergoing anterior cruciate ligament reconstruction.It is recommended to use neuromuscular electrical stimulation to intervene in the quadriceps and hamstring in the early postoperative stage and implement explosive force and high resistance training in the late postoperative stage,which may improve the isometric rate of force development in patients.Generating sufficient muscle strength in a short period of time is necessary to effectively protect the anterior cruciate ligament,while the relationship between isometric rate of force development in the hamstring muscle and functional performance is still unclear,which may provide information on preventing secondary injury in patients.It is recommended to use the isometric rate of force development as one of the evaluation indicators for guiding rehabilitation and restoring movement.In addition to focusing on improving symmetry and differences from normal individuals,the hamstring to quadriceps strength ratio should also be considered.An appropriate range of ratios can ensure the balance of muscles during rapid muscle exertion,which may reduce the occurrence of secondary injuries.However,the normal range of ratios is not yet clear.Future research should consider the effects of graft type and knee flexion angle on isometric rate of force development,in order to identify neuromuscular dysfunction in patients as much as possible and help them recover better.

Objective:To screen the aging genes closely associated with pelvic organ prolapse(POP)by bioinformatics techniques,and to clarify the potential clinical significance and value of key genes.Methods:Gene Expression Omnibus(GEO)Database was used to download the datasets GSE53868 and GSE151188 for POP-related genes with the keyword"pelvic organ prolapse".The aging-related genes were obtained from Aging Atlas,CellAge,and the Human Ageing Genomic Resources(HAGR)Databases;the intersection of genes related with POP in two groups provided a list of differentially expressed genes(DEGs)associated with aging in POP;gene Set Enrichment Analysis(GSEA)was conducted with R software version 4.2.1;Gene Ontology(GO)functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)signaling pathway enrichment analysis of DEGs were conducted by the Database for Annotation,Visualization and Integrated Discovery(DAVID);the protein-protein interaction(PPI)network was constructed with Cytoscape 3.9.1 software;the top 10 Hub genes were selected by cytoHubba plugin;the infiltration of 22 types of immune cells in the patients in POP group and control group was analyzed by CIBERSORT deconvolution method using R software;the key genes were further screened by LASSO regression algorithm;the correlation and diagnostic efficacy between key genes and immune cell infiltration were analyzed.Results:From the Aging Atlas,CellAge,and HAGR Databases,724 aging-related genes were identified.Intersection with the POP expression profile yielded an aging gene expression matrix related to POP containing 624 genes,and 29 POP-related DEGs were identified after differential analysis,including 2 upregulated genes and 27 downregulated genes.The GSEA results showed that the upregulated pathways were mainly related to diabetes and cellular senescence,whereas the downregulated pathways included Alzheimer's disease and hypoxia-inducible factor-1(HIF-1)signaling pathways.The GO functional enrichment analysis mainly enriched in the biological processes such as the response of the cells to lipopolysaccharide,inflammatory response,and negative regulation of cell proliferation.The KEGG signaling pathway enrichment analysis mainly enriched in interleukin-17(IL-17),tumor necrosis factor(TNF),and nuclear factor-kappa B(NF-κB)signaling pathways.The PPI network analysis got 10 Hub genes including interleukin-6(IL-6),interleukin-1B(IL-1B),prostaglandin-endoperoxide synthase 2(PTGS2),and NF-kappa-B inhibitor alpha(NFKBIA).The CIBERSORT deconvolution method results showed a relatively higher infiltration proportion of neutrophils and activated mast cells in the patients in POP group,the activated mast cells had a positive correlation with most of the DEGs(r>0.5)and the macrophages had a significant positive correlation with IL-1B(r>0.6).The key genes Jun D proto-oncogene(JUND),Snail homolog 1(SNAI1),amphiregulin(AREG),Lamin A/C(LMNA),and superoxide dismutase 2(SOD2)selected by LASSO regression analysis had high diagnostic efficacies,and the area under receiver operating characteristic curve(ROC)(AUC)were all greater than 0.75.Conclusion:During the aging process,the genes such as JUND,SNAI1,AREG,LMNA,and SOD2 may participate in the pathophysiology of POP through various pathways,including inflammation-related pathways,transcription regulation,and affecting collagen secretion and metabolism,thereby influence the connective tissue support function and promote the occurrence and development of POP.