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Background: Osteoarthritis (OA) is a degenerative joint disease. Understanding contributing factors to slowing or stopping disease progression is crucial. There has been no research describing lower extremity kinematics of the hip, knee, and ankle during stair ambulation in individuals with hip OA., Objective: To explore the differences in lower extremity kinematics between participants with clinical and morphological findings of hip OA and controls., Design: A cross-sectional study., Setting: Clinical research laboratory., Participants: Participants with radiographic and symptomatic signs of hip OA (n = 42) and healthy controls (n = 30) were enrolled., Interventions: Participants underwent hip magnetic resonance imaging (MRI). The Scoring Hip Osteoarthritis with MRI (SHOMRI) method was used to assess cartilage abnormalities. Self-reported measures of hip pain and function were obtained using the Hip Disability and Osteoarthritis Outcome Score (HOOS). Participants were assigned into a symptomatic hip osteoarthritis group (HOA) with SHOMRI>0 and HOOS≤80, and a control group (CG) with SHOMRI = 0 and HOOS>90. Patients underwent 3D motion analysis during stair ascent/descent at self-selected speed., Main Outcome Measures: The primary outcome measurements were peak hip, knee, and ankle kinematics. General Estimation Equations were used to compare kinematics between groups (P ≤ .05)., Results: The HOA group ascended stairs with a more internally rotated hip (CG = 1.77 ± 6.3; HOA = 4.97 ± 4.2; P = .02), more abducted hip (CG = -5 ± 2.7, HOA = -3.5 ± 3; P = .02), and a more externally rotated knee (CG = -8.02 ± 3; HOA = -10.63 ± 6.3; P = .02) and ankle (CG = -11.8 ± 6.1; HOA = -16.3 ± 5.6; P = .01). Similarly, HOA participants descended stairs with a more extended knee (CG = -15.5 ± 4.9; HOA = -12 ± 4.9; P = .01), and more externally rotated knee (CG = -10.1 ± 4.4; HOA = -13.1 ± 6.6; P = .04) and ankle (CG = -13.5 ± 5.3; HOA = -17.9 ± 5.5; P = .002)., Conclusion: Participants with hip OA-related morphology and symptoms ambulate stairs utilizing abnormal lower extremity mechanics., (© 2020 American Academy of Physical Medicine and Rehabilitation.)

Background: Iliotibial band syndrome has been associated with altered hip and knee kinematics in runners. Previous studies have recommended further research on neuromuscular factors at the hip. The frontal plane hip muscles have been a strong focus in strength comparison but not for electromyography investigation., Objective: To compare hip surface electromyography, and frontal plane hip and knee kinematics, in runners with and without iliotibial band syndrome., Design: Observational cross-sectional study., Setting: Biomechanics research laboratory within a university., Participants: Thirty subjects were recruited consisting of 15 injured runners with iliotibial band syndrome and 15 gender-, age-, and body mass index-matched controls. In each group, 8 were male runners and 7 were female runners. Inclusion criteria for the injured group were pain within 2 months related to iliotibial band syndrome and a positive Noble compression test. Participants were excluded if they reported other lower extremity diagnoses within the last year or active lower extremity or low back pain not related to iliotibial band syndrome. Controls were excluded if they reported a history of iliotibial band syndrome. Convenience sampling was used based on referrals from local running clinics and orthopedic clinics., Methods: Three-dimensional motion capture was performed with 10 high-speed cameras synchronized with wireless surface electromyography during a 30-minute run. The first data point was at 3 minutes, using a constant speed of 2.74 meters per second. A second data point was at 30 minutes, using a self-selected pace by the participant to allow for a challenging run until completion at 30 minutes., Main Outcome Measurements: Motion capture was reported as peak kinematic values from heel strike to peak knee flexion for hip adduction and knee adduction. Surface electromyography was reported as a percentage of maximal voluntary contraction for the gluteus maximus, gluteus medius and tensor fascia latae muscles., Results: Injured runners demonstrated increased knee adduction compared with control runners at 30 minutes (P = .002, control = -1.48°, injured = 3.74°). Tensor fasciae latae muscle activation in injured runners was increased compared with control runners at 3 minutes (P = .017, control = 7% maximal voluntary isometric contraction, injured = 11% maximal voluntary isometric contraction)., Conclusion: The results of this study suggest that lateral knee pain in runners localized to the distal iliotibial band is associated with increased knee adduction at 30 minutes. Increased tensor fasciae latae muscle activation at 3 minutes is noted, but more investigation is needed to better understand the clinical meaning. These findings are consistent with but not conclusive evidence supporting the theory that neuromuscular factors of the hip muscles may contribute to increased knee adduction in runners with iliotibial band syndrome. We advise caution using these findings to support treatments intended to modify tensor fasciae latae activation, given the small differences of 4% in muscle activation. Increased knee adduction in runners at 30 minutes was over 5° and beyond the minimal detectable difference. Additional research is needed to confirm whether the degree of knee adduction changes earlier versus later in a run and whether fatigue is a clinically relevant factor., Level of Evidence: III., (Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Background: Few studies have investigated the associations between patient-reported outcome and gait in patients with anterior cruciate ligament (ACL) injury and reconstruction over time. Because there is an association between ACL rupture and the presence of osteoarthritis later in life, a better understanding of these relationships will help to elucidate how patients' gait pattern may affect pain and symptoms, potentially leading to better treatment for or preventing the development of knee OA., Objective: To evaluate the associations between gait characteristics and self-reported pain and symptoms before, 6 months after, and 1 year after anterior cruciate ligament reconstruction., Design: Prospective cohort study., Setting: The Human Performance Center at the Orthopedic Institute at the University of California, San Francisco., Patients: Patients with full unilateral ACL tears were enrolled. A total of 43 patients were included at 12 months postsurgery., Methods: The independent variable in this study comprised specific gait variables in patients who had undergone ACL reconstruction. At each time point, 3-dimensional motion analysis was performed. Participants also completed the Knee Osteoarthritis Outcome Score (KOOS) questionnaire., Main Outcomes Measurements: The primary study outcome measurement was the KOOS and was planned before data collection began. Partial correlations were used to examine cross-sectional associations between gait characteristics and KOOS pain and symptom scores at all time points. In addition, partial correlations were performed to examine the associations between change in postoperative KOOS from 6 months to 1 year and gait characteristics at baseline and 6 months., Results: Significant associations between KOOS and gait characteristics were found at all time points, including an association between peak medial ground reaction force and pain (r = -0.344, P = .02) and symptoms (r = -0.407, P = .007) at baseline., Conclusions: Specific gait variables may be predictive of greater pain and symptoms and less improvement over time postreconstruction. This could help to inform rehabilitation exercises post injury and pre reconstruction., Level of Evidence: IV., (Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Background: Femoroacetabular impingement (FAI) is a morphological abnormality of the hip joint that causes pain when performing a mechanically demanding activity of daily living such as the sit-to-stand (STS) task. Previous studies have assessed lower extremity joint mechanics during an STS task in various pathologies, yet the STS task has not been studied in FAI patients., Objective: The objective of this study was to identify differences in joint kinetics and performance between FAI patients and healthy controls during a STS task. It was hypothesized that FAI patients would exhibit altered time needed to complete the STS task, as well as altered lower extremity biomechanics, when compared to healthy controls., Design: This was a cross-sectional cohort study., Setting: The study took place at a motion capture laboratory at an institutional orthopedic facility., Participants: Biomechanical analysis was performed in 17 FAI patients and 31 age- and body mass index (BMI)-matched healthy controls during the STS task., Methods: Sagittal plane joint moments, total support moment (TSM), joint contributions to the TSM, and functional measures during the STS task were compared between groups., Main Outcome Measurements: Peak joint moments, TSM and joint contributions to the TSM were assessed during the STS task. In addition, the time to and value of the peak vertical ground reaction force (vGRF), limb symmetry index at peak vGRF, loading rate, and total time needed to perform the STS task were determined., Results: Compared to the control participants, the FAI patients exhibited worse Hip Disability and Osteoarthritis Outcome Score (HOOS) pain and function subscores. No group differences were observed in peak sagittal joint moments during the STS task. However, when compared to controls, the FAI patients demonstrated reduced knee joint contributions to the TSM. In addition, the FAI patients exhibited increased time needed to perform the STS task, increased time to reach peak vGRF, and reduced lower extremity loading rate during the STS task., Conclusions: FAI patients demonstrated abnormal joint contributions to TSM and altered functional performance during the STS task. These altered movement patterns during the STS task may be compensatory mechanisms used by the FAI patients to reduce pain and to improve function., Level of Evidence: Not applicable., (Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the changes in running biomechanics after training in form-focused running using ChiRunning versus not-form focused training and self-directed training in untrained individuals., Design: Pilot study-randomized controlled trial., Setting: Research institution with tertiary care medical center., Participants: Seventeen subjects (9 men, 8 women) with prehypertension., Methods: Twenty-two participants were randomized to 3 study arms but 17 completed the study. The study arms were: (1) group-based Form-Focused running using ChiRunning (enrolled, n = 10; completed, n = 7); (2) group-based conventional running (enrolled, n = 6; completed, n = 4); and (3) self-directed training with educational materials (enrolled, n = 6; completed, n = 6). The training schedule was prescribed for 8 weeks with 4 weeks of follow-up. All subjects completed overground running motion analyses before and after training. ClinicalTrials.gov identifier for this study is NCT0158718., Outcomes: Ankle, knee, hip joint peak moments, and powers; average vertical loading rate (AVLR); impact peak; cadence; stride length; strike index; and stride reach. Paired t tests were used to compare differences within groups over time., Results: Form-focused group reduced their Stride Reach (P = .047) after the training but not the other groups. Form-focused group showed a close to significant reduction in knee adduction moment (P = .051) and a reduction in the peak ankle eversion moment (P = .027). Self-directed group showed an increase in the running speed (P = .056) and increases in ankle and knee joint powers and moments., Conclusions: There are differences in the changes in running biomechanics between individuals trained in running form that emphasizes mid-foot strike, greater cadence, and shorter stride compared with those not trained in the these techniques. These differences may be associated with reduced lower extremity stress in individuals trained in this running form, but more studies are needed to confirm these findings in larger samples., (Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the prevalence and characteristics of recreational runners with medial and lateral heel whips., Design: Observational cohort study., Setting: Clinical research laboratory., Participants: A total of 256 recreationally active runners and joggers participated., Main Outcome Measures: High-definition video was acquired from a posterior view while runners ran at a self-selected pace on a treadmill. Heel whips, defined as the medial or lateral rotation of the foot in the transverse plane during initial swing, were measured with Dartfish software. Subjects were stratified by direction (medial and lateral) and severity (W_5-10 = 5-10 degrees; W_10+ = >10 degrees) of heel whip. Body mass index and gender comparisons, as well as measurement reliability, also were explored., Results: Mean heel whip angle across runners was 0.4 degrees (medial) with a standard deviation of 9.2 degrees. Of the 512 feet analyzed, 274 (54%) demonstrated a 5 degree whip or greater. There was a similar number of medial and lateral heel whips observed (27% each). Female runners were twice as likely to demonstrate a lateral heel whip of greater than 8.9 degrees. Overweight runners had more medially directed whips when compared with normal and underweight runners., Conclusions: More than half of the recreational runners studied were observed to have a medial or lateral heel whip of greater than 5 degrees. These data reveal the age, body mass index, and gender distribution of recreational runners with and without heel whips., (Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

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-landing tasks. Experienced radiologists graded 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 landing 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-landing 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 understanding the complex interplay between bony morphologic features, cartilage lesions, and movement patterns in persons with cam-type FAI., (Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Muscle performance factors and altered loading mechanics have been linked to a variety of lower extremity musculoskeletal disorders. In this article, biomechanical risk factors associated with iliotibial band syndrome (ITBS) are described, and a strategy for incorporating these factors into the clinical evaluation of and treatment for that disorder is presented. Abnormal movement patterns in runners and cyclists with ITBS are discussed, and the pathophysiological characteristics of this syndrome are considered in light of prior and current studies in anatomy. Differential diagnoses and the use of imaging, medications, and injections in the treatment of ITBS are reviewed. The roles of hip muscle strength, kinematics, and kinetics are detailed, and the assessment and treatment of muscle performance factors are discussed, with emphasis on identifying and treating movement dysfunction. Various stages of rehabilitation, including strengthening progressions to reduce soft-tissue injury, are described in detail. ITBS is an extremely common orthopedic condition that presents with consistent dysfunctional patterns in muscle performance and movement deviation. Through careful assessment of lower quarter function, the clinician can properly identify individuals and initiate treatment., (Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)