***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 The purpose of the present study was to see if there is a learning effect of repeated static stabilometric testing , using a protocol suitable for testing postural control in narrow spaces , like hypo- and hyperbaric chambers . HYPOTHESIS Static stabilometry testing under normobaric conditions is objective and reproducible . With repeated testing , a learning effect may be observed . METHODS Four groups of healthy individuals were tested ten times under the same four acoustically and visually st and ardized and normobaric normoxic test conditions on a static balance platform . First , the subjects were asked to st and on a bare platform with the eyes open , thereafter with the eyes closed . This was repeated with a foam rubber mat placed on top of the balance platform . The time interval between the first and the last test sequence was 11 ( 10 - 13 ) days for the test subjects in group I ( n = 22 ) , 17 d for group II ( n = 13 ) , 31(28 - 36 ) days for group III ( n = 15 ) and 115 ( 49 - 193 ) days for group IV ( n = 10 ) . RESULTS Static stabilometry tests in a normal population are objective and reproducible . With repeated tests , a learning effect was observed . The learning effect was largest when st and ing on a foam rubber mat with eyes closed and when the time intervals between the tests were shortest . There was no difference in sway pattern or learning ability between tall and short test subjects , between subjects with heavy and light body weight or between the sexes Background and Purpose The purpose of this study was to determine the effect of a 6-month neuromuscular training ( NT ) program versus a traditional strength training ( ST ) program following anterior cruciate ligament ( ACL ) reconstruction . Subjects Seventy-four subjects with ACL reconstruction participated in the study . Methods The study was a r and omized , single-blinded , controlled trial . The NT and ST groups were tested preoperatively and at 3 and 6 months . The main outcome measure was the Cincinnati Knee Score . Secondary outcome measures were visual analog scales ( VASs ) for pain and function , the 36-Item Short-Form Health Survey ( SF-36 ) , hop tests , isokinetic muscle strength , proprioception , and static and dynamic balance tests . Results The NT group demonstrated significantly improved Cincinnati Knee Scores and VAS scores for global knee function compared with the ST group at the 6-month follow-up . There were no significant differences between the groups for the other outcome measures ( ie , hop , balance , proprioception , and muscle strength tests ) . Discussion and Conclusion The results of this study suggest that exercises included in the NT program should be part of the rehabilitation program following ACL reconstruction Objective : To compare the effect of a whole body vibration training ( WBVT ) programme with a conventional training ( CT ) programme on knee proprioception and postural stability  after anterior cruciate ligament ( ACL ) reconstruction . Methods : Twenty athletes with unilateral ACL reconstruction were r and omly assigned to the WBVT or CT group ; all participants received 12 sessions of WBVT or conventional training . Absolute error in joint repositioning for two target angles ( 30 ° and 60 ° ) was measured with the Biodex dynamometer ; bilateral dynamic postural stability ( anteroposterior , mediolateral and overall stability indices ) was measured with the Biodex Stability System pre-intervention and post-intervention . Results : The improvement in postural stability in the WBVT group was significantly greater than that in the CT group ( p⩽0.05 ) . The p values of the changing scores of open overall , open anteroposterior , open mediolateral , closed overall , closed anteroposterior and closed mediolateral stability indices were 0.002 , 0.010 , 0.0001 , 0.001 , 0.0001 and 0.046 , respectively . In addition , there were significant differences in all averages of absolute angular error at 60 ° and 30 ° between the WBVT and CT groups in both knees ( p = 0.001 in healthy knees and p = 0.001 and p = 0.0001 in reconstructed knees ) , apart from the healthy knees at the 30 ° target position , which was not significant ( p = 0.131 ) . Conclusions : Whole body vibration training improved proprioception and balance in athletes with reconstructed ACL The purpose of the present investigation was to evaluate physical outcome after  anterior cruciate ligament ( ACL ) reconstruction with early versus late initiation of open kinetic chain ( OKC ) exercises for the quadriceps in patients operated on either patellar tendon or hamstring grafts . Sixty-eight patients , 36 males and 32 females , with either patellar tendon graft ( 34 patients ) or hamstring graft ( 34 patients ) were enrolled in this study . All patients were r and omly allocated to either early ( the 4th postoperative week ) or late ( the 12th postoperative week ) start of OKC exercises for the quadriceps , result ing in four subgroups : patellar tendon reconstruction , early start ( P4 ) or late start ( P12 ) of OKC quadriceps exercises , hamstring tendon reconstruction , early start ( H4 ) or late start ( H12 ) of quadriceps OKC exercises . Prior to surgery and 3 , 5 and 7 months later , assessment s of range of motion ( goniometer ) , anterior knee laxity ( KT-1000 ) , postural sway ( KAT 2000 ) , thigh muscle torques ( Kin – Com dynamometer ) and anterior knee pain ( anterior knee pain score ) were evaluated . No significant group differences were found in terms of range of motion 3 , 5 and 7 months postoperatively . The H4 group showed a significantly higher mean difference of laxity over time of 1.0 mm ( CI : 0.18–1.86 ) than the P4 group ( P = 0.04 ) . Within the same type of surgery , the H4 against the H12 , the mean difference over time was 1.2 mm ( 0.37–2.1 ) higher in the H4 group than in the H12 group ( P = 0.01 ) . There were no significant group differences in terms of postural sway or anterior knee pain at the different test occasions . Significant differences in trends ( changes over time ) were found when comparing the four groups , for both quadriceps muscle torques ( P < 0.001 ) and hamstring muscle torques ( P < 0.001 ) . All groups , except the P4 group , reached preoperative values of quadriceps muscle torques at the 7 months follow-up . In the H4 and the H12 groups , significantly lower hamstring muscle torques at the 7 months follow-up compared with preoperative values were found . In conclusion , early start of OKC quadriceps exercises after hamstring ACL reconstruction result ed in significantly increased anterior knee laxity in comparison with both late start and with early and late start after bone – patellar tendon – bone ACL reconstruction . Furthermore , the early introduction of OKC exercises for quadriceps did not influence quadriceps muscle torques neither in patients operated on patellar tendon nor hamstring tendon grafts . On the contrary , it appears as if the choice of graft affected the strength of the specific muscle more than the type of exercises performed . Our results could not determine the appropriate time for starting  OKC quadriceps exercises for patients who have undergone ACL reconstruction with hamstring tendon graft . Future studies of long-term results of anterior knee laxity and functional outcome are needed PURPOSE To evaluate the effects an  anterior cruciate ligament ( ACL ) brace  has on various measures of knee proprioception and postural control . METHODS Thirty subjects ( mean age 27 + /- 11 yr ) having undergone unilateral ACL reconstruction were tested with and without wearing their own custom-fit brace on their involved limb . Proprioception was assessed using joint angle replication tests completed on an isokinetic dynamometer . Postural control was assessed using a series of single-limb st and ing balance tests completed on a force platform . The balance tests included : 1 ) st and ing on the stable platform with eyes open , 2 ) st and ing on a foam mat placed over the platform with eyes open , 3 ) st and ing on the platform with eyes closed , and 4 ) st and ing on the platform after l and ing from a maximal single-limb forward hop . RESULTS The brace provided a small but statistically significant improvement in proprioception ( mean reduction in error scores between target and reproduced angles = 0.64 + /- 1.4 degrees , P = 0.02 ) . For the postural control tests , there was a significant brace condition by test situation interaction ( P = 0.02 ) , with the brace providing a small but statistically significant improvement during the test completed on the stable platform with eyes open ( mean reduction in center of pressure path length = 4.2 + /- 8.4 cm , P = 0.02 ) but not during the other more challenging test situations . Additional post hoc analyses indicated that the relationship between knee proprioception and postural control measures were low and not significant ( r = 0.003 to 0.19 , P > 0.32 ) , consistent with the suggestion that changes in knee proprioception can occur in the absence of substantial changes in postural control . Also , st and ing balance tests that challenged the somatosensory contribution to postural control ( i.e. , those completed on foam , or with eyes closed ) were significantly related to single-limb forward hop distances ( r = -0.4 , P < 0.05 ) , whereas performance during the proprioception test was not ( r = 0.1 , P > 0.50 ) . CONCLUSIONS In general , bracing appears to improve performance during tasks characterized by relatively limited somatosensory input but not during tasks characterized by increased somatosenory input . The small magnitude of the improvements , coupled with their apparent lack of carry over to more difficult and functionally relevant tasks , questions the clinical benefit of the present effects of bracing OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity Total sagittal knee laxity and postural control in the sagittal and frontal planes were measured in 25 patients at a mean of 36 months ( range , 27 to 44 ) after anterior cruciate ligament reconstruction and in a control group consisting of 20 uninjured age- and activity-matched subjects .  Body sway was measured in the sagittal plane on a stable and on a sway-referenced force plate in single-legged stance , double-legged stance , or both , with the eyes open and closed . Postural reactions to perturbations in the sagittal and frontal planes were recorded in the single-legged stance with the eyes open . Total sagittal plane laxity was significantly greater in the anterior cruciate ligament-reconstructed knee ( 11.2 mm ; range , 6 to 15 ) than in the uninjured knee ( 8.9 mm ; range , 6 to 12 ) or in the control group ( 6.0 mm ; range , 5 to 8) . In spite of this , the patients , in comparison with the controls , exhibited normal postural control except in two variables — the reaction time and the latency between the start of force movement to maximal sway in the sagittal plane perturbations . This supports the hypothesis that rehabilitation , with proprioceptive and agility training , is an important component in restoring the functional stability in the anterior cruciate ligament-reconstructed knee Proprioceptive function of the knee was quantified and compared in three groups of patients : those with ante rior cruciate ligament deficiency , with hamstring ten dons-ligament augmentation device anterior cruciate ligament reconstructions , and with bone-patellar ten don-bone anterior cruciate ligament reconstructions .  A total of 32 subjects , including 6 uninjured control sub jects , were tested for threshold to perception of passive motion of the knee . 
    Output:
    
In static balance tasks , there was a trend towards improved postural control in the control group for eyes-open but not eyes-closed conditions .
Nonetheless , there was evidence to suggest impaired postural control in patients following ACL reconstruction surgery when compared to controls , particularly for more challenging tasks .