RÉSUMÉ
Walking downstairs and running are common actions in daily life;however,older adults with functional decline are prone to falls or injuries.To cope with various situations and avoid falls,the first neuroprotective motor mechanism activated by the body is the regulation of lower limb stiffness.Hence,this study retrieved and collected relevant research results from databases such as China Knowledge,Wanfang,Google Scholar,and Web of Science,using key words such as elderly and lower limb stiffness,and summarized the similarities and differences in changes in lower limb stiffness in different action tasks.The findings show that interventions on controllable factors can improve changes in lower limb stiffness to prevent falls in older adults.However,owing to the small number of related studies,it is necessary to further investigate the effects of action interventions on lower limb stiffness in older adults to obtain reliable regularity features and references.
RÉSUMÉ
OBJECTIVE:The effect of post-activation potentiation on sports performance is characterized by increased muscle mobility and increased rate of muscle force generation.In this paper,Meta-analysis is used to quantitatively evaluate the effects of post-activation potentiation on sprint speed,jumping performance,and kinetic parameters(peak impulse,peak power,maximum ground reaction force,rate of force generation,etc.)after activation of relative strength levels in the lower limbs. METHODS:Electronic databases such as CNKI,WanFang,Web of Science,PubMed,and Medline were retrieved for randomized control,random crossover,or clear grouping according to the relative strength levels of the lower limbs(non-randomized controls)on the post-activation potentiation effect after activation induced by the relative strength level of the lower limbs.Free weight equipment and rapid telescopic compound exercises were used as main intervention methods in each group.The publication time of the literature was from the inception of each database until August 5,2023.Endnote software was used to manage the literature.Literature quality assessment was conducted using the PEDro scale for randomized controlled trials and ROBINS-I 2.0 standards for non-randomized controlled trials.Revman5.4 and Stata15.0 software were used to conduct publication bias evaluation,subgroup analysis and sensitivity analysis of the extracted data,and forest plots were produced for Meta-analysis. RESULTS:Eleven documents(seven randomized controlled trials and four non-randomized controlled trials)were finally included,including 216 subjects.Overall,the methodological quality of the literature was high.According to the grouping standard of 1-repetition maximum/body mass>2 for the strong group and 1-repetition maximum/body mass≤2 for the normal group,there were 99 subjects in the strong group and 117 subjects in the normal group,all of whom were male.The positive effect of post-activation potentiation on sprint performance in the strong group was significantly higher than that in the normal group[standardized mean difference(SMD)=-1.34,95%confidence interval(CI):-1.74 to-0.93,P<0.000 01];the positive effect of post-activation potentiation on vertical jump height showed no significant difference between the strong and normal group(SMD=0.30,95%CI:-0.07 to 0.66,P=0.11);the positive effect of post-activation potentiation showed no significant difference between the strong and normal groups in terms of peak impulse(SMD=-0.07,95%CI:-0.62 to 0.47,P=0.61],peak power(SMD=0.21,95%CI:-0.29 to 0.72,P=0.12),maximum ground reaction force(SMD=0.31,95%CI:-0.20 to 0.81,P=0.16)and force generation rate(SMD=0.36,95%CI:-0.11 to 0.82,P=0.39). CONCLUSION:The post-activation potentiation effect in the strong group can significantly increase the short-distance sprint speed.The potentiation effect after activation of the relative strength level of the lower limbs has similar effects on the kinematic and kinetic parameters,including explosive vertical jump height,peak impulse,peak power,maximum ground reaction force and force generation rate.