***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: The purpose of the present study was to investigate whether different  walking patterns in healthy subjects and in coper and non-coper subjects with deficient anterior cruciate ligaments could be quantified . An inverse dynamics approach was used to calculate joint kinematics and kinetics for flexion and extension . EMG signals of the hamstrings and quadriceps muscles were recorded . The results showed that the peak knee flexion angle was greater in the copers than in the controls . There was a positive correlation between the peak knee extensor moment and peak knee flexion angle . Furthermore , at a given peak knee flexion angle , the peak knee extensor moment was significantly larger in the controls than in the non-copers . The hip extensor moment in the copers was significantly larger than that of the non-copers and the controls . In conclusion , the three groups walked according to different patterns . It is suggested that the copers stabilized their knee joint by co-contraction of the hamstrings and quadriceps muscles , while the non-copers lacked this ability . Instead , the non-copers reduced the knee extensor moment in order to decrease anterior displacement of the tibia . The walking pattern differences observed between the copers and non-copers may explain their different post-injury activity levels Stair ascent and descent requires large knee motions and muscle forces that can be challenging for people with anterior cruciate ligament ( ACL ) deficiency .  Movement and muscle activity patterns  were compared in two groups of ACL deficient subjects and a group of uninjured subjects .  The ACL deficient subjects were prospect ively classified according to functional ability . " Copers " were defined as individuals with complete ACL rupture and no symptoms of knee instability and participated in high-level sports without difficulty . " Non-copers " were defined as ACL deficient individuals who had instability with low-level daily activities and were not able to participate in sports . Sagittal plane kinematic and kinetic data from the hip , knee and ankle and electromyographic data from the vastus lateralis , lateral hamstring , medial gastrocnemius , and soleus were collected as subjects stepped up and over a 26 cm high step . Both coper and non-coper subjects had altered movement patterns as they controlled the rapid movement from step ascent to descent with their involved limbs . Only non-copers used significantly different movement patterns on their involved limb compared to controls after they had descended from the step and their involved side accepted the weight of the body . Classifying subjects by functional ability result ed in more pronounced differences in movement patterns between non-copers and copers . Copers moved more like uninjured subjects Abstract The aim of this study is to analyse the changes in select gait parameters following  anterior cruciate ligament ( ACL ) reconstruction .  The study was performed on 15 subjects who underwent ACL reconstruction by the bone-patellar tendon-bone technique .  Gait analysis was performed using the Elite three-dimensional ( 3D ) optoelectronic system ( BTS ) , a Kistler force platform and the Telemg telemetric electromyograph ( BTS ) .  Kinematic data were recorded for the principal lower limb joints ( hip , knee and ankle ) . The examined muscles include vastus lateralis , rectus femoris , biceps femoris and semitendinosus . The results obtained from the operated subjects were compared with those of 10 untreated subjects and 5 subjects without ACL damage .  In the operated subjects the knee joint angular values regained a normal flexion pattern for the injured limb during the stance phase . The analysis of joint moments shows : ( a ) sagittal plane : recovery of the knee flexion moment at loading response and during preswing ; ( b ) frontal plane : recovery of the normal patterns for both hip and knee adduction-abduction moments during the entire stance phase . The examination of ground reaction forces reveals the recovery of frontal component features . The EMG traces show the normal biphasic pattern for the operated subjects as compared to the untreated subjects . The results suggest that the gait parameters shift towards normal value patterns OBJECTIVE To establish the gait adaptations of patients with anterior cruciate ligament deficiency during stair ascent .  DESIGN Joint kinematics and kinetics during stair climbing were measured in both knees of normal subjects and unilateral anterior cruciate ligament deficient patients . BACKGROUND As there is limited research pertaining to activities other than level walking , the purpose of the current study was to eluci date the gait of patients with anterior cruciate ligament deficiency during stair climbing  to determine the effects of the deficiency on knee joint motion and moments as compared with normal knee function . METHODS A motion analysis system was used to measure and  calculate kinematic and kinetic data  for six normal subjects and nine patients with unilateral anterior cruciate ligament deficiency during stair ascent on a specially constructed staircase .  Left and right leg data were analysed to reveal between-limb differences for each subject . RESULTS Patients with anterior cruciate ligament deficiency displayed a significant ( P < 0.05 ) reduction of up to 50 % in peak knee flexion moments in their involved knee . In the present study where a step height of 15.5 cm was used , peak flexion moments in all subjects ' limbs occurred at knee flexion angles of about 40 degrees during single limb support . CONCLUSION The current study showed that most patients with an anterior cruciate deficient knee adapted their gait during stair ascent . RELEVANCE As stair climbing is a common activity , its effect on gait is relevant to better underst and appropriate treatment and management strategies of patients with anterior cruciate ligament deficient knees The objective of this study is to determine how kinematical parameters and electromyography data of selected muscles may change as a result of anterior cruciate ligament ( ACL ) deficiency and following ACL reconstruction .  The study was conducted on 25 anterior cruciate ligament deficient subjects prior to and 6 weeks , 4 months , 8 months and 12 months following ACL reconstructive surgery using the bone-patellar tendon-bone technique .  Gait analysis was performed by applying the zebris three-dimensional ultrasound-based system with surface electromyograph ( zebris ) .  Kinematic data were recorded for the lower limb . The muscles surveyed include vastus lateralis and medialis , biceps femoris and adductor longus . The results obtained from the injured subjects were compared with those of 51 individuals without any ACL damage whatsoever . Acute ACL deficient patients exhibited a quadriceps avoidance pattern prior to and 6 weeks following surgery . No quadriceps avoidance phenomenon develops in chronic ACL deficient patients . In operated individuals , tempo-spatial parameters and the knee angle regained a normal pattern for the ACL-deficient limb during gait as early as 4 months following surgery . However , the relative ACL movement parameter , which describes the tibial translation into the direction of ACL , and the EMG traces show no significant statistical difference compared with the same values of the healthy control group just 8 months following surgery . The analysis of spatial-temporal parameters and EMG traces show that the development of a quadriceps avoidance pattern is less common than previously reported . These data suggest that anterior cruciate ligament deficiency and reconstruction produce considerable changes in the lower extremity gait pattern . The results suggest that gait parameters tend to shift towards a normal value pattern ; and the re-establishment of pre-injury gait patterns-including the normal biphase of muscles-takes at least 8 months to occur 
    Output:
    
INTERPRETATION Effect sizes comparing knee joint moments in injured vs. healthy control subjects appear to be slightly higher while jogging than walking , and higher in ACL-deficient patients compared to reconstructions .
Consequently , it is difficult to make inferences with confidence during these tasks