***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background : We aim ed to determine if a shock absorbing pylon ( SAP ) influenced the ground reaction force characteristics and the shock absorbing mechanisms compared to a rigid pylon ( Rigid ) during the loading phase in running . Objectives : To determine if the SAP influences the mechanisms of loading compared to the Rigid condition . Study Design : A convenience sample of transtibial amputees participated in a laboratory-based study . The prosthetic set-up was r and omly altered fd\sdsd . Methods : Five recreationally active male transtibial amputees age : 18–50 years ; mean mass : 86.7 ± 17.5 kg ; height : 1.77 ± 0.07 m ) volunteered from a population -based sample . They completed a within-participant- design ed study assessing a SAP and a Rigid condition during running . Kinematic and kinetic data were collected during two sessions following a one-week customization period . Results : Loading rate , peak vertical and horizontal ground reaction forces and the time to each measure along with knee and hip angular displacement , absorbing powers and work done between the SAP and Rigid conditions were not systematic ally affected by the prosthetic condition . Conclusions : The effect of the SAP was minimal and inconsistent in the loading phase , with only some amputees presenting higher and others with lower values for the tested variables . Clinical relevance The inclusion of a prosthetic shock absorber in the form of a SAP did not systematic ally alter the kinetic characteristics or shock absorbing mechanisms of the residual joints . It appears that the prescription of a SAP is not justified for these recreationally active amputees Background It is possible that cross-over studies included in current systematic review s are being inadequately assessed , because the current risk of bias tools do not consider possible biases specific to cross-over design . We performed this study to evaluate whether this was being done in  cross-over studies included in Cochrane  Systematic Review s ( CSRs ) . Methods We search ed the Cochrane Library ( up to 2013 issue 5 ) for CSRs that included at least one cross-over trial . Two authors independently undertook the study selection and data extraction . A r and om sample of the CSRs was selected and we evaluated whether the cross-over trials in these CSRs were assessed according to criteria suggested by the Cochrane h and book . In addition we reassessed the risk of bias of these cross-over trials by a checklist developed form the Cochrane h and book . Results We identified 688 CSRs that included one or more cross-over studies . We chose a r and om sample of 60 CSRs and these included 139 cross-over studies . None of these CSRs undertook a risk of bias assessment specific for cross-over studies . In fact items specific for cross-over studies were seldom considered anywhere in quality assessment of these CSRs . When we reassessed the risk of bias , including the 3 items specific to cross-over trials , of these 139 studies , a low risk of bias was judged for appropriate cross-over design in 110(79 % ) , carry-over effects in 48(34 % ) and for reporting data in all stages of the trial in 114(82 % ) . Assessment of biases in cross-over trials could affect the GRADE assessment of a review ’s findings . Conclusion The current Cochrane risk of bias tool is not adequate to assess cross-over studies . Items specific to cross-over trials leading to potential risk of bias are generally neglected in CSRs . A proposed check list for the evaluation of cross-over trials is provided Amputees lack movement and control mechanisms at the foot and ankle that result in different strategies for locomotion than nonamputees . The torsion adapter is a prosthetic device design ed to minimize shear stress at the residual limb by facilitating rotation in the transverse plane . This study determined if the addition of a torsion adapter alters lower-limb joint rotation moments of transtibial amputees walking in a straight line and turning . Ten transtibial amputees wore either a torsion adapter or a rigid adapter for an acclimation period of 3 weeks in r and om order . Ten nonamputees were also included for comparison . Kinetics were collected as participants walked in a straight line and around a 1 m-radius circular path at their self-selected turning walking speed . When amputee participants wore the torsion adapter , they demonstrated decreased prosthetic-limb peak internal rotation moments at the inside limb knee and hip compared with when they wore the rigid adapter , which may facilitate changes in orientation by not actively resisting the turn . Nonamputees exhibited larger moments compared with the prosthetic limb for both the amputee participants wearing either the torsion or rigid adapters . No differences were found in the moments for the intact limb between torsion and rigid adapter conditions during turning and for both limbs during straight-line walking OBJECTIVE To investigate the effects of 3 dissimilar suspension systems on participants '  satisfaction and perceived problems with their prostheses . DESIGN Question naire survey . SETTING A medical and engineering research center and a university biomedical engineering department . PARTICIPANTS Persons with unilateral transtibial amputation ( N=243 ) , using prostheses with polyethylene foam liner , silicone liner with shuttle lock , and seal-in liner . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Descriptive analyses were performed on the demographic information , satisfaction , and prosthesis-related problems of the study participants . RESULTS The results showed significant differences between the 3 groups regarding the degree of satisfaction and perceived problems with the prosthetic device . Analyses of the individual items revealed that the study participants were more satisfied with the seal-in liner and experienced fewer problems with this liner . The silicone liner with shuttle lock and seal-in liner users reported significant differences in maintenance time compared with the polyethylene foam liner . Users of the silicone liner with shuttle lock experienced more sweating , while those who used the seal-in liner had greater problems with donning and doffing the device . CONCLUSIONS The results of the survey provide a good indication that prosthetic suspension is improved with the seal-in liner as compared with the polyethylene foam liner and silicone liner with shuttle lock . However , further prospect i ve studies are needed to investigate which system provides the most comfort and the least problems for participants OBJECTIVE To develop an accurate method for quantifying the frequency content of the ground reaction force transient . DESIGN Repeated measures design comparing the impact severity during walking with different  insole material s. BACKGROUND The body experiences a brief but sizeable impact upon heel strike during walking . This impact transient is believed to result in musculoskeletal injuries . It is important to accurately quantify this impact as a step towards decreasing the risk of injury . METHODS Seven subjects walked barefoot at their normal cadence across a force platform , while insole material s ( Spenco , Microcel-puff , and Plastazote ) were placed on the surface of the force platform . A filterbank program was developed to determine the percent root mean square in 10 Hz frequency b and s from zero to 400 Hz . Analysis focused on the impact transient contained in a 20 ms window after heel contact . RESULTS The high frequency ( > 60 Hz ) power was significantly larger in the barefoot condition compared to the insole conditions . The barefoot condition also result ed in significantly higher initial peak forces and force loading rates . CONCLUSIONS The frequency content of the ground reaction force can be effectively quantified using a filterbank approach . Shoe insole material s can reduce the initial peak force , force loading rate , and frequency content of the impact transient in walking . The frequency content of the initial ground reaction force extends up to 400 Hz in some footwear conditions . RELEVANCE The new filterbank procedure illustrates that the vertical ground reaction force in walking has a higher frequency content than previously thought . This signal requires high sampling rates to avoid aliasing , and appropriate signal processing algorithms , such as filter banks , for analysis Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more BACKGROUND Chronic low back pain ( LBP ) is a common musculoskeletal impairment in people with lower limb amputation . Given the multifactorial nature of LBP , exploring the factors influencing the presence and intensity of LBP is warranted . OBJECTIVE To investigate which physical , personal , and amputee-specific factors predicted the presence and intensity of LBP in persons with nondysvascular transfemoral amputation ( TFA ) and transtibial amputation ( TTA ) . DESIGN A retrospective cross-sectional survey . SETTING A national r and om sample of people with nondysvascular TFA and TTA . PARTICIPANTS Participants ( N = 526 ) with unilateral TFA and TTA due to nondysvascular etiology ( ie , trauma , tumors , and congenital causes ) and a minimum prosthesis use of 1 year since amputation were invited to participate in the survey . The data from 208 participants ( 43.4 % response rate ) were used for multivariate regression analysis . METHODS ( INDEPENDENT VARIABLES ) Personal ( ie , age , body mass , gender , work status , and presence of comorbid conditions ) , amputee-specific ( ie , level of amputation , years of prosthesis use , presence of phantom-limb pain , residual-limb problems , and nonamputated limb pain ) , and physical factors ( ie , pain-provoking postures including st and ing , bending , lifting , walking , sitting , sit-to-st and , and climbing stairs ) . MAIN OUTCOME MEASURES ( DEPENDENT VARIABLES ) LBP presence and intensity . RESULTS A multivariate logistic regression model showed that the presence of 2 or more comorbid conditions ( prevalence odds ratio [ POR ] = 4.34 , P = .01 ) , residual-limb problems ( POR = 3.76 , P < .01 ) , and phantom-limb pain ( POR = 2.46 , P = .01 ) influenced the presence of LBP . Given the high LBP prevalence ( 63 % ) in the study , there is a tendency for overestimation of POR , and the results must be interpreted with caution . In those with LBP , the presence of residual-limb problems ( β = 0.21 , P = .01 ) and experiencing LBP symptoms during sit-to-st and task ( β = 0.22 , P = .03 ) were positively associated with LBP intensity , whereas being employed demonstrated a negative association ( β = -0.18 , P = .03 ) in the multivariate linear regression model . CONCLUSIONS Rehabilitation professionals should be cognizant of the influence that comorbid conditions , residual-limb problems , and phantom pain have on the presence of LBP in people with nondysvascular lower limb amputation .  Further prospect i ve studies could investigate the underlying causal mechanisms of LBP . LEVEL OF EVIDENCE II We studied impact loading on the foot and ankle at heel strike during level walking . Cadaveric testing was carried out on a skin-mounted accelerometer to estimate the bone or joint impact , and gait analysis was performed to evaluate the impact on the foot and ankle and its attenuation during level walking . Simulation using a rigid-body model estimated the impulse at l and ing during level walking . The skin-mounted accelerometer showed the same tendency as the bone-mounted accelerometer in cadaveric testing . In the gait analysis , impact at the calcaneus was attenuated at the medial malleolus and was less attenuated with the ankle fixation . In the simulation , impact became greater if the foot and ankle functions were eliminated . These results suggest that the foot and ankle are directly involved in attenuating the impact at heel strike during level walking N-of-1 or single subject clinical trials consider an individual patient as the sole unit of observation in a study investigating the efficacy or side-effect profiles of different interventions . The ultimate goal of an n-of-1 trial is to determine the optimal or best intervention for an individual patient using objective data -driven criteria . Such trials can leverage study design and statistical techniques associated with st and ard population -based clinical trials , including r and omization , washout and crossover periods , as well as placebo controls . Despite their obvious appeal and wide use in educational setting s , n-of-1 trials have been used sparingly in medical and general clinical setting s. We briefly review the history , motivation and design of n-of-1 trials and emphasize the great utility of modern wireless medical monitoring devices in their execution . We ultimately argue that n-of-1 trials dem and serious attention among the health research and clinical care communities given the contemporary focus on individualized medicine OBJECTIVES : Athletic footwear are associated with frequent injury that are thought to result from repetitive impact . No scientific data suggest they protect well . Expensive athletic shoes are deceptively advertised to safeguard well through " cushioning impact " , yet account for 123 % greater injury frequency than the cheapest ones . This study tested the hypothesis that deceptive advertising creates a false sense of security with users of expensive athletic shoes , inducing attenuation of impact moderating behaviour , increased impact , and injury . METHODS : Fifteen young healthy male volunteers confronted four surfaces : a bare force moment platform , and three with this platform covered  by  identical shoe sole material made to appear different and advertised divergently . Advertising messages suggested superior impact absorption and protection ( deceptive message ) , poor impact absorption and high injury risk ( warning message ) , and unknown impact absorption and safety ( neutral message ) . Ground reaction forces were recorded for 10 barefoot footfalls , according to a protocol requiring stepping forward from perch to a surface 4.5 cm below . RESULTS : Impact varied as a function of advertising message ( p < 0.001 ) . Deceptive message equalled neutral message in eliciting higher impact than the warning message and the bare platform . Differences grew with repet 
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Conclusion : While the current body of literature does not reconcile with cl aims made by manufacturers of shock-attenuating pylons , it is insufficient to conclusively determine how effective shock-attenuating pylons are , in comparison with conventional rigid pylons , in attenuating transient impact forces among lower limb amputees .