***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 Femoroacetabular impingement is a common hip pathology result ing in pain and impaired physical function . However , very little is known about gait differences between those with and without femoroacetabular impingement . Thus , the purpose of this study was to compare three-dimensional gait kinematics and kinetics between those with femoroacetabular impingement and a healthy , pain-free control group . METHODS Three-dimensional gait analysis was conducted on 30 individuals with symptomatic femoroacetabular impingement scheduled for surgery and 30 pain-free controls .  Spatiotemporal and peak hip kinematics and joint moments were compared between the two groups . Ensemble averages were also calculated for kinematic and kinetic profiles across the gait cycle in all three planes of movement for visual inspection . FINDINGS Participants with femoroacetabular impingement walked slower and with significantly smaller cadences than those in the control group . Kinematically , the impingement group exhibited significantly less peak hip extension , adduction and internal rotation during stance , with effect sizes ranging from 0.48 ( adduction ) to 1.00 ( internal rotation ) . Finally , those with FAI exhibited significantly less peak external hip flexion ( effect size=0.52 ) and external rotation ( effect size=0.85 ) moments than the control group . INTERPRETATION Individuals with femoroacetabular impingement exhibit differences in gait kinematics in all planes of motion compared to those with without FAI . These findings support the need for focused neuromuscular reconditioning across all movement directions in this patient group OBJECTIVE To determine if compensatory actions take place at the pelvis and other joints of the affected lower limb in subjects who were in an early stage of hip osteoarthritis ( OA ) . DESIGN Nonr and omized , case-control study . SETTING A gait laboratory . PARTICIPANTS Seventeen patients with OA of the hip ( clinical group ) matched with 17 healthy elderly subjects ( non clinical group ) . INTERVENTIONS Video data obtained while subjects walked a 10-meter walkway twice and stepped across a forceplate . MAIN OUTCOME MEASURES Four phasic and temporal gait parameters ( walking speed , stance phase relative duration , stride length , cadence ) 10 pelvic ( pelvic tilt , obliquity , rotation at push-off maximum range of motion for all 3 ) and hip ( 3 hip angles at push-off , maximum hip flexion ) kinematic parameters , 3 hip moments , and twenty-seven 3-dimensional peak muscle powers ( labeled by joint , peak power , plane ) developed in the lower limb joints during the gait cycle . RESULTS Subjects in the clinical group were characterized by a 12.4 % slower walking speed . The pelvis was more upwardly tilted ( 2.5 times ) at push-off in the clinical group than in the non clinical group . Obliquity , measured in the frontal plane , revealed that the pelvis dropped more ( 2.4 times ) on the unsupported limb of the clinical group at push-off . In the sagittal plane , subjects in the clinical group absorbed less energy in their second hip peak power for decelerating the thigh extension and generated less hip pull ( third hip peak power ) than the non clinical group by 34 % and 29 % , respectively . In the sagittal plane , the clinical group had 57 % lower second knee peak power to straighten the joint shortly after heel strike , and 43 % less knee absorption ( third peak power ) at push-off . During the push-off phase , the clinical group developed more than twice their third peak knee power in the frontal plane and 5 times more their third peak knee power in the transversal plane than the peak knee power of the non clinical group in an attempt to control knee adduction and to facilitate body-weight transfer by an internal rotation . At the end of the swing phase , the fourth peak power in the sagittal plane showed the absorption power required to decelerate the leg ; it was reduced by 35 % in the clinical group , representing a strategy to increase walking speed by lengthening the stride length . CONCLUSIONS Even at an early stage of hip OA , joint degeneration was compensated by an increase in pelvis motion and muscle power generation or absorption modifications in other lower limb joints Objective To determine the association between cam impingement , which is hip incongruity by a non-spherical femoral head and development of osteoarthritis . Methods A nationwide prospect i ve cohort study of 1002 early symptomatic osteoarthritis patients ( CHECK ) , of which st and ardised anteroposterior pelvic radiographs were obtained at baseline and at 2 and 5 years follow-up . Asphericity of the femoral head was measured by the α angle . Clinical ly , decreased internal hip rotation ( ≤20 ° ) is suggestive of cam impingement . The strength of association between those parameters at baseline and development of incident osteoarthritis ( K&L grade 2 ) or end-stage osteoarthritis ( K&L grade s 3 , 4 , or total hip replacement ) within 5 years was expressed in OR using generalised estimating equations . Results At baseline , 76 % of the included hips had no radiographic signs of osteoarthritis and 24 % doubtful osteoarthritis . Within 5 years , 2.76 % developed end-stage osteoarthritis . A moderate ( α angle > 60 ° ) and severe ( α angle > 83 ° ) cam-type deformity result ed in adjusted OR of 3.67 ( 95 % CI 1.68 to 8.01 ) and 9.66 ( 95 % CI 4.72 to 19.78 ) , respectively , for end-stage osteoarthritis . The combination of severe cam-type deformity and decreased internal rotation at baseline result ed in an even more pronounced adjusted OR , and in a positive predictive value of 52.6 % for end-stage osteoarthritis . For incident osteoarthritis , only a moderate cam-type deformity was predictive OR=2.42 ( 95 % CI 1.15 to 5.06 ) . Conclusions Individuals with both severe cam-type deformity and reduced internal rotation are strongly predisposed to fast progression to end-stage osteoarthritis . As cam impingement might be a modifiable risk factor , early recognition of this condition is important Gluteus minimus is believed to consist of two structurally and functionally unique segments ( anterior and posterior ) ; however there is a lack of electromyography ( EMG ) research that attempts to verify current theoretical knowledge of this muscle . The purpose of this study was therefore to evaluate the function of gluteus minimus during gait , and to determine whether anterior and posterior segments are functionally independent . Bipolar fine wire intramuscular EMG electrodes were inserted into anterior and posterior gluteus minimus segments of fifteen healthy volunteers ( 9 males ) according to previously verified guidelines . Participants completed a series of four walking trials , followed by maximum voluntary isometric contractions in five different positions  . Temporal and amplitude variables for each segment were compared across the gait cycle with independent t-tests . The relative contribution of each segment to the maximum resisted trials was compared with Mann-Whitney U tests ( α = 0.05 ) . Anterior and posterior segments were contracting at different relative intensities for three of the five maximum resisted trials ( effect size = 0.39 to 0.62 , P < 0.037 ) . The posterior segment was larger in EMG amplitude ( peak and average ) during the first 20 % of the gait cycle ( effect size = 0.96 to 1.03 , P < 0.02 ) , while the anterior segment peaked later in the stance phase ( effect size = 0.83 , P = 0.034 ) . Gluteus minimus is therefore composed of functionally independent segments . These results build on contemporary theoretical knowledge and may signify hip stabilising roles for each segment across different phases of the gait cycle OBJECTIVE To investigate the differences in hip movement patterns during different daily and athletic activities in persons with cam-type femoroacetabular impingement ( FAI ) with and without cartilage lesions compared with control subjects in a preliminary study . DESIGN Controlled laboratory study using a cross-sectional design . SETTING Research institution with a tertiary care medical center . PARTICIPANTS Fifteen subjects [ M : F , 13:2 ; age , 31.6 ± 9.7 years ( range , 22 - 52 years ) ; body mass index , 24.9 ± 4.6 ( range , 18.8 - 38.4 ) ; FAI : control , 7:8 ] . METHODS All subjects had 3-Tesla magnetic resonance imaging of the hip and also underwent 3-dimensional motion capture during walking , deep-squat , and drop-l and ing tasks . Experienced radiologists grade d cartilage lesions on clinical magnetic resonance images . OUTCOMES Peak kinematic and kinetic variables were compared between subjects who did and did not have FAI , and subjects who had FAI and cartilage lesions were compared with subjects who did not have cartilage lesions . RESULTS Subjects who had FAI demonstrated no significant differences for walking or drop l and ing compared with control subjects . However , during the deep-squat task , subjects with FAI adducted more and had a greater internal rotation moment . Subjects who had cartilage lesions in the presence of a cam lesion demonstrated ( 1 ) no difference for walking ; ( 2 ) greater adduction , greater internal rotation moment , and lower transverse plane range of motion during the deep-squat task ; and ( 3 ) greater adduction and lower internal rotation during the drop-l and ing task compared with subjects who did not have cartilage lesions . CONCLUSIONS We observed differences in movement patterns between subjects who had FAI compared with control subjects . However , the differences were more pronounced between subjects with FAI who had cartilage lesions compared with subjects who did not have cartilage lesions . These findings highlight the importance of underst and ing the complex interplay between bony morphologic features , cartilage lesions , and movement patterns in persons with cam-type FAI 
    Output:
    
Conclusion This review suggests that patients with FAIS may demonstrate hip biomechanical impairments during walking and squatting , with minimal literature available to comment on other tasks .
Clinical relevance The information presented in the review provides insight into the biomechanical differences associated with FAIS ; however , the between-group differences were small to moderate .