Research

  • I. Improving Outcomes following ACL Reconstruction
        Longitudinal Assessment of Knee Loading Throughout Rehabilitation
        Using Movement Quality Feedback to Reduce Compensatory Strategies in Individuals Following ACL Reconstruction
        Does Early Gait Training Improve Lower Extremity Sagittal Plane Loading following ACL Reconstruction?
        Quantification of Daily Gait Behaviors in Individuals Status-post ACL Reconstruction

    II. ACL Injury Prevention
        The Development of Postural Strategies Necessary for Dynamic Activities
        Whole body Mechanics of Running Turn Maneuvers: Relationship to Injury and Performance

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    I. Improving Outcomes following ACL Reconstruction
      
    The rate of re-injury to the anterior cruciate ligament (ACL) after returning to sports is 15 times greater in individuals who have had an anterior cruciate ligament reconstruction (ACLr) compared to healthy athletes. Females are four times more likely to re-injure their reconstructed knee and 4 times more likely to tear their contralateral ACL. A recent study found that 16 out of 63 athletes sustained another ACL injury within one year of their release to return to sports.

     

    Although restoration of normal lower extremity mechanics is one of the primary goals of rehabilitation, loading strategies that shift the mechanical demands away from the knee extensors of the reconstructed joint have been found to persist up to two years post-operatively. This is of particular concern as these strategies are attributed to increased risk for re-injury, injury to the contralateral limb and progression of knee osteoarthritis. While these loading strategies coincide with decreased quadriceps strength, they are found to persist after the resolution of quadriceps strength deficits. 

    It is possible that individuals adopt compensatory strategies early after surgery or injury that continue into late rehabilitation. Weight bearing is encouraged soon after surgery to promote graft healing however; the ability to restore typical loading patterns during early gait training is challenged by the presence of postoperative pain, quadriceps strength deficits and decreased range of motion. Compensatory loading patterns that reduce knee loading are likey adopted during early rehabiliton. It is not known how traditional rehabilitation exercises ameliorate these altered mechaincs.

     

    Compensatory gait patterns are adopted early to reduce the loading of the knee and persist after the resolution of joint impairments. As gait is a repetitive, daily activity it may be difficult to restore typical loading patterns with traditional physical therapy interventions.  

     
    Longitudinal Assessment of Knee Loading Throughout Rehabilitation 
     
    The aim of this project is to quanitfy loading patterns during gait and progressively more demanding functional tasks during early and late rehabilitation to determine the effects of traditional rehabilitation on improvement of knee loading and the development of compensatory patterns. This information will be used to inform the development targeted interventions. Three dimensional lower extremity and trunk biomechanics during gait, squatting, running, and landing will be collected longitudinally at 4, 8, 16, 20, 24 and 28 weeks on 100 patients following ACL reconstruction. Additional information including subject demographics, anthropometrics, injury and medical history, surgical procedure, rehabilitation compliance, activity and work history, and psychosocial factors will be analyzed to determine the influence of potential confounding factors on rehabilitation progress.
     
    Related publications:
     
    Abstracts:
    Sigward SM, Lin PE, Pratt KA, Pucciarelli MLR. Gait Mechanics During Early Phases Of Anterior Cruciate Ligament Reconstruction Rehabilitation. Medicine and Science in Sports and Exercise, Volume 46:5S. American College of Sports Medicine, Orlando, FL. 2014 

    Lin PE, Pratt KA, Pucciarelli MLR, Sigward SM. Knee Loading Asymmetries During Early Phases Of Anterior Cruciate Ligament Reconstruction Rehabilitation. Medicine and Science in Sports and Exercise, Volume 46:5. American College of Sports Medicine, Orlando, FL. 2014

    Investigators: Susan Sigward PhD, PT, ATC, Kristamarie Pratt MEng, Paige Lin, Ming-Sheng Chan MS 

    Research Assistants: Sarah Ebner, Christy Maguire, Kristina Scott, Will Hill, Caleb Pagliero, Jon Tam
     
    Using Movement Quality Feedback to Reduce Compensatory Strategies in Individuals Following ACL Reconstruction
     
    Despite improvements in research based rehabilitation programs, individuals continue to limit sagittal plane loading of the knee during functional activities 4-6 months after anterior cruciate ligament reconstruction (ACLr). This is of concern as this is the time during which they begin to perform high level activities (i.e. hopping, running, cutting). Individuals adopt compensatory strategies that shift the mechanical demands away from the knee to adjacent joints. The persistence of these strategies during the late phases of rehabilitation suggests that the progression through multi-joint functional exercises, the foundation of ACL rehabilitation programs, is not adequately preventing the adoption of compensatory patterns. Improved strategies targeting sagittal plane knee loading during rehabilitation exercises is warranted. 

     

    This project focuses on providing movement quality feedback during a single limb loading task to individuals following ACLr. It explores the use of wearable sensor technology to identify and ameliorate altered sagittal plane knee loading strategies during functional exercises. 3D video motion analysis is the most sensitive instrument for assessing joint demands during dynamic tasks; however, the expense, expertise and time needed to capture data preclude its use for clinical exercise training. Recent advances in wearable technology make it possible to collect segmental kinematic data during dynamic tasks and may provide an alternative to 3D video systems for relaying objective information regarding knee joint loading in the clinic. This work aims to develop and validate a clinical tool for quantifying altered movement patterns typically observed following ACLr. By providing clinicians and patients with objective information regarding movement quality, information obtained from this project will help develop patient specific training programs and improve outcomes following rehabilitation. 

    Investigators: Kristamarie Pratt MEng, Susan Sigward PhD, PT, ATC

    Research Assistants: Sarah Ebner 

    Collaborators: Robert Gregor PhD, Robert Keim PhD, Kornelia Kulig PhD, PT, George Salem PhD
     
    Does Early Gait Training Improve Lower Extremity Sagittal Plane Loading following ACL Reconstruction?

    Although restoration of normal gait mechanics is one of the primary goals of rehabilitation, gait deviations that shift the mechanical demands away from the knee extensors of the reconstructed joint have been found to persist up to 2 years post-operatively after anterior cruciate ligament reconstruction (ACLr). These deviations have been attributed to post-operative joint impairments. However, they have been found to persist well after the resolution of joint impairments suggesting that individuals may adopt a new loading motor program during early rehabilitation. Modest improvements in sagittal plane loading attained as a result of gait training following ACLr suggest that emphasis on normalizing gait mechanics during the early stages of rehabilitation may counteract the development of faulty loading patterns. The purpose of this study is to expand on this work to determine the effects of a progressive gait training program on sagittal plane knee loading mechanics during gait in early rehabilitation. 
     
    Fifteen individuals between 18-40 years who are 4 weeks post ACLr will be recruited (gait training group; GT) and 15 age and sex matched individuals (control group; CT). Individuals in the GT group will be instructed in an 8-week progressive spatial-temporal gait intervention. In addition, both groups will receive traditional physical therapy. Gait analysis performed at 4, 8, 12 and 16 weeks following surgery will correspond to pre, mid, post and follow-up intervention assessments. A 2x4 ANOVA with repeated measures analysis will be used to determine the effects of gait training on knee loading over time. Protocol and therapy progression and adherence will be recorded to determine feasibly of the proposed intervention and to account for potential confounders. It is expected that greater improvements in knee loading will be observed during gait in the GT than the CT group at each time point. Greater improvements will suggest that, in addition to traditional physical therapy, specific gait training during early rehabilitation could be an effective stimulus for preventing the persistence of maladaptive loading strategies. These data will be used to determine the feasibility and efficacy of the proposed intervention and to calculate statistical power for a larger clinical trial.
     
    Investigators: Paige Lin, Susan Sigward PhD, PT, ATC, 

    Research Assistants: Sarah Ebner

    Funding: California Physical Therapy Fund, 1/2014-12/2014 ($9,095)
     
    Quantification of Daily Gait Behaviors in Individuals Status-post ACL Reconstruction
     
    Existing standard clinical gait assessments depend on visual observation of gait deviations when relatively small alterations in kinematics often exist concurrently with large sagittal plane loading deficits 4-12 weeks after surgery. This makes clinical/observational assessment of gait difficult limiting the clinician’s ability to identify and address these deficits. Moreover, it is not known how gait patterns observed in the clinic relate to ambient gait behaviors. It is conceivable that attention to movement quality during rehabilitation sessions does not carry over into daily activities with different time and attentional demands. Daily gait behaviors may provide a strong stimulus for the development of maladaptive strategies; thus, it is important to understand how they are related. This pilot study will be the first critical step in developing methods for characterization and evaluation of gait in this population outside the constraints of video or marker based motion analysis. This study will utilize inertial measurement unit (IMU) sensors to characterize and quantify spatio-temporal parameters of status-post ACLr gait. This approach differs from the traditional analysis of individual joint kinematics and kinetics, and will enable researchers and clinicians to define metrics of gait performance useful in the understanding, treatment and prevention of maladaptive gait mechanics following ACLr. 
     
    Investigators: Susan Sigward PhD, PT, ATC, Eric Wade PhD, Ming-Sheng Chan MS. 

    Funding: Boston Rehabilitation Outcomes Measurement Pilot Project, 3/2014-2/2015 ($30,000)

     
    II. ACL Injury Prevention  
    The anterior cruciate ligament (ACL) is a major stabilizing structure of the knee. Injury to the ACL can lead to joint instability during landing and pivoting tasks. It is particularly devastating to athletes because it is often season ending and sometimes career ending with long-term consequences including knee joint instability and osteoarthritis. In athletic populations ACL reconstruction is often required to restore stability to the joint followed by 6-12 months of rehabilitation. Injuries classified as noncontact are of particular interest because they are two to five times more prevalent in female athletes and result from a mechanism that does not involve direct contact to the knee.
     
    ACL Project Prevent began in 2005 as a 3-year research study funded by the National Institutes of Health (NIH). The primary objective of this study was to identify sex specific movement patterns that predispose female athletes to anterior cruciate ligament (ACL) injuries during sport activities and to determine the influence of maturation on the development of these movement patterns. Analysis of data from over 150 male and female soccer players, ages 8-26, provided important insights into potentially injurious movement patterns and the emergence of these patterns across stages of maturation (work published in citations below). This work continues through several specific projects listed below. 
     
    Related publications:

    Manuscripts: 

    Sigward SM, Pollard CD, Havens KL, Powers CM. The influence of Sex and Maturation on Knee Mechanics During Side-step Cutting, Medicine & Science in Sports & Exercise,44(8): 1497-1503, 2012.

    Sigward SM, Pollard CD, Powers CM. The Influence of Sex and Maturation on Landing Biomechanics: Implications for ACL Injury. Scandinavian Journal of Medicine & Science in Sports, 22(4):502-509, 2012.
     
    Sigward SM, Havens KH, Powers CM. The relation between knee separation distance and lower extremity kinematics during a drop land: Implications for clinical screening. Journal of Athletic Training, 46(5):471-75, 2011.
     
    Pollard CD, Sigward SM, Powers CM. Limited Hip and Knee Flexion During Landing is Associated with Increased Frontal Plane Knee Motion and Moments. Clinical Biomechanics, 25(3):142-46, 2010.
     
    Lyle MA, Sigward SM, Tsai L-C, Pollard CD, Powers CM. The influence of Maturation and Lower Extremity Biomechanics on Peak Foot Velocity in Young Females During a Soccer Kick. Medicine & Science in Sports & Exercise, 43(10): 1948-1954, 2011.
     
    The Development of Postural Strategies Necessary for Dynamic Activities  

     
    Increasing participation in physical activity during childhood is important for the mitigation of health issues related to inactivity and for shaping adult activity behaviors. Children who do not achieve age-appropriate motor skills tend to avoid participation in physical activities and adopt a more sedentary lifestyle. The ability to respond to dynamic challenges to postural equilibrium during running tasks underlies many skills needed for successful participation in childhood activities as it enables individuals to appropriately change direction and speed in response to task demands. An understanding of the processes that constrain and drive acquisition of postural strategies needed for participation in physical activity is necessary to identify developmental delays and to inform the creation of interventions aimed at facilitating acquisition of mature movement patterns. The current literature in this area is limited to the development of postural strategies for balance, gait termination and obstacle avoidance and has not considered dynamic tasks needed for participation in physical activities. 

    The objective of this study is to use a running gait termination paradigm to quantify differences in postural strategies in typically developing pre-pubertal children ages 7-12 and to compare these strategies to those employed by young adults. Three-dimensional motion analysis, force platforms and electromyography will be used to characterize the strategies individuals used to decelerate from a run. Strategies will be compared between children and to young adults (20-35yrs). It is expected that differences between groups will characterize the development of more mature postural strategies to control whole body momentum with age. This study will expand the body of work examining the maturation of postural strategies and data collected in a previous NIH study (#1R01HD046663-01). These will serve as pilot data for a larger longitudinal study that will include an expanded assessment of mechanical, neural and cognitive variables to determine the extent to which these variables constrain or promote acquisition of mature movement patterns across development. 

    Related publications:

    Abstracts:

    Cesar GM, Lewthwaite R, Joutras DM, Parvez AH, Gow I, Sigward SM. Child-Adult Differences in the Control of the Body Forward Momentum with Practice. North American Society for Psychology of Sport and Physical Activity, Minneapolis, MN. 2014-Podium Presentation
     
    Cesar GM, Joutras DM, Parvez AH, Sigward SM. Children and Adults Employ Different Strategies to Terminate Running Gait. Medicine and Science in Sports and Exercise, Volume 46:5. American College of Sports Medicine, Orlando, FL. 2014- Poster Presentation
     
    Cesar GM, Parvez AH, Sigward SM. Postural Strategies for Running Gait Termination: Comparison Between Children and Adults. Proceedings for the International Society of Biomechanics Annual Conference. Natal, Brazil 2013-Poster Presentation.
     
    Investigators: Guilherme Cesar PT, MS, Susan Sigward PhD, PT, ATC

    Research Assistants: Alia Parvez, Dawn Joutras, Irene Gow 

    Collaborators: Rebecca Lewthwaite PhD, Robert Keim PhD, James Gordon EdD, PT, Kornelia Kulig PhD, PT, FAPTA 

    Funding: Zumberge Fund Individual Grant ($27,000); North American Society for Psychology of Sports and Physical Activity (NASPSPA) ($2,000)
     
    Whole body Mechanics of Running Turn Maneuvers: Relationship to Injury and Performance  

     
    This project focuses on sports maneuverability and investigates the mechanics used by healthy athletes to perform quick changes of direction during running. Agility is essential to participation in many multi-directional sports. However, change of direction tasks are associated with knee injuries, particularly anterior cruciate ligament (ACL) injury. This type of injury occurs frequently, and injury prevention programs have been created aimed at decreasing the risk of injury and improving mechanics thought to be associated with injury. Yet it is not clear how these recommended changes in mechanics relate to successful performance of change of direction tasks for the athlete. 
     
    In order to inform both injury prevention and sports performance research, this project investigates the effects of velocity and change of direction magnitude on whole body mechanics and anticipatory adjustments made during quick change of direction maneuvers. Healthy college and professional soccer players perform cutting tasks in the state-of-the-art laboratory, and their movements are captured with motion analysis cameras and embedded force platforms, then analyzed using custom software. Information obtained from this project will be useful in the development of effective injury prevention and rehabilitation protocols as well as improving our understanding of human maneuverability and sports performance. 

     

    Related publications:

    Manuscripts: 
    Havens KL and Sigward SM. Whole Body Postural Mechanics of Running Turn Maneuvers. Gait & Posture, In revisions 
     
    Havens KL and Sigward SM. Joint and Segmental Mechanics of Running Turn Maneuvers. Gait & Posture, In revisions 
     
    Abstracts:

    Havens KL, Sigward SM. Biomechanics associated with cutting performance and ACL injury risk. Combined Sections Meeting of the American Physical Therapy Association. Las Vegas, NV. February, 2014. Podium Presentation

     
    Havens KL, Sigward SM. Whole body posture for running change of direction tasks. Proceedings for the American Society of Biomechanics Conference. Omaha, NE. September, 2013. Poster Presentation
     
    Havens KL, Sigward SM. Biomechanics associated with excessive ankle inversion during a cutting maneuver. American College of Sports Medicine Annual Meeting. Indianapolis, IN. May, 2013. Poster Presentation
     
    Havens K, Cesar G, Sigward S. Center of Mass Position-Velocity Relationship for the Control of Running Gait Termination. Proceedings for the Gait and Clinical Movement Analysis Society Conference. Grand Rapids, MI. May, 2012; Podium Presentation
     
    Havens KL, Sigward SM. Deceleration: Relationship Between Body Posture and Velocity. Proceedings for the American Society of Biomechanics Annual Conference. Gainesville, FL. August, 2012; Poster Presentation
     
    Havens KL, Sigward SM. Deceleration and Redirection Mechanics During a Cutting Maneuver. Proceedings for the American Society of Biomechanics Conference. Long Beach, CA. August, 2011; Poster Presentation
     
    Investigators: Kate Havens MS, PhD, Susan Sigward PhD, PT, ATC

    Research Assistants: Richard Peterson, Daniela Roark, Annabelle Maman 

    Collaborators: George Salem PhD, Robert Gregor PhD, Beth Fisher PhD, PT, Robert Keim PhD