Abstract Archive

This study determined whether active lower limb muscle volume increased when landing with load and whether it differed between sexes or landing type. Twenty male and seventeen female participants had active hip, knee and ankle muscle volume quantified when performing normal and flexed landings with ...

Deficits in quadriceps strength are common following anterior cruciate ligament reconstruction (ACL-R) and can influence alterations in gait mechanics. Functional resistance training (FRT) may improve gait mechanics, yet, the best approach to implement FRT is not clear. Here, we report the acute eff...

Research and design of ankle-foot prostheses has largely focused on optimizing ankle function; however, the potential benefits of modifying the foot keel remain relatively unexplored. In particular, the addition of a toe joint has the potential to positively impact the gait biomechanics of prostheti...

The purpose of this study was to investigate the associations between range of motion (ROM) and stiffness of muscle, fascia and nerve in young and elderly individuals. Ankle dorsiflexion ROM was determined based on onset of pain using a dynamometer. Tissue stiffness was evaluated by ultrasound shear...

Individuals with lower extremity bone tumors (osteosarcoma or Ewing’s sarcoma) have complex reconstructive procedures which may result in changes to muscle architecture. This preliminary work demonstrates the use of static and extended field-of-view ultrasound to measure architecture of the vastus...

The purpose of this study is to understand variable gearing in medial gastrocnemius (MG) muscle of chronic stroke survivors, as estimated from the “fascicle gear ratio.” Five stroke survivors performed isometric plantarflexions at different ankle joint angles. During each contraction, ankle torq...

Knee osteoarthritis (KOA) is a painful and debilitating disease that is accelerated by excessive loading in the joint. Personalized gait modifications that reduce the first peak of the knee adduction moment (P1KAM), can improve joint pain [3], but require visits to a laboratory equipped with expensi...

This abstract describes an analysis technique using a single, sacrum-worn inertial sensor to estimate kinetic descriptors of sprint performance. The ability of the proposed technique to assess sprint performance is demonstrated and compared to a previously validated photocell-based method.

Arthrogenic muscle inhibition (AMI) is a known phenomenon that causes reflex inhibition of muscles that surround the injured joint. The mechanisms of AMI remain unclear. Novel decomposed electromyography (dEMG) technology may reveal motor unit (MU) firing frequency and recruitment of AMI. EMG was co...

Ankle sprains are one of the most common musculoskeletal injuries, leading to chronic ankle instability (CAI) in 30-40% of first-time sprains. Clinicians assess passive stability under non-weight-bearing conditions, but their relevance to weight-bearing conditions when ankle sprains occur is unclear...

We examined the discriminant ability of features extracted from walking and running contact force data using instrumented insoles in order to optimize future classification model accuracy. Twenty-seven subjects walked and ran on four treadmills with varying deck stiffness at both self-selected and c...

We compared joint kinetics among three footwear types in inexperienced and experienced runners. Minimal footwear increased plantarflexor involvement while highly cushioned footwear increased knee extensor involvement. Experienced runners ran with greater plantarflexor involvement than inexperienced ...

At short sarcomere lengths (SLs) (1.9 to 2.65 µm) single muscle fibres from old individuals had a greater mean passive modulus than those from young. This resulted in a greater passive stress in the old group at SLs between 2.1 and 3.55 µm. Conversely, at long SLs (i.e. > 3.55 µm) the single fibr...

There is limited information on the effect of foot strike angle (FSA) on the resultant ground reaction force vector angle (θR-GRF) and the leg vector angle (θL). Human participants ran on a treadmill with a forefoot strike (FF) and a rearfoot strike (RF) according to biofeedback criteria of their ...

The purpose of this study was to describe neuromuscular and kinematic differences between failed and successful single-leg landings. Twenty-four healthy teen athletes completed unanticipated single-leg drop-jump landings on their dominant limb. Failed landings exhibited increased trunk and pelvis fl...

Musculoskeletal ultrasound imaging (USI) was used to assess gluteal muscle activity throughout walking gait among healthy individuals, patients with chronic ankle instability (CAI), and lateral ankle sprain “copers”. While gluteus maximus activity was comparable across groups throughout the gait...

We present an automatic workflow for generating patient specific finite element models of the knee from MRI. A neural network was trained on 20 segmented MRI, and tested on 5 MRIs. A custom python workflow was used to automatically create FE models. The workflow had a mean error of 0.83 mm, and on a...

This study aimed to describe the amount, trajectories and reliability of the upper cervical spine mobilisations in axial rotation and flexion-extension directions in terms of combined rotational and translational motion components. Twenty fresh human cervical specimens were investigated in a test-re...

This study aimed to investigate the ankle joint power during stair ascent in different foot initial contact strategies and to find a better strategy. Twenty healthy young men performed stair ascent with two different initial contact methods, i.e., rear-foot strike and forefoot strike. Forefoot strik...

Insertional Achilles tendinopathy (IAT) is a common condition in recreational athletes that causes heel pain. The recurring pain may trigger load compensation mechanisms and concomitantly lead to strength and gait asymmetries. 15 patients with unilateral IAT performed maximal isometric ankle plantar...

We hypothesize that acto-myosin cross-bridge cycling dynamics govern history-dependence in muscle mechanics and muscle spindle afferent feedback that may impact human postural behaviors. Here we combine in vitro, in vivo, and in silico studies to determine movement amplitude thresholds affecting his...

The intrinsic foot muscles are known to contribute to postural control during upright stance and locomotion. However we know little about the role of these muscles in stabilization following unexpected perturbations. We conducted an experiment in which subjects were trained to repeatedly step at a p...

This research examined age-related changes in muscle strength and multi-channel surface electromyography (EMG) spatial parameters during isometric and isokinetic knee extensions. Peak torque, mean EMG amplitude, intensity, entropy and Coefficient of Variation (CV) were compared across age and sex. W...

These data provide an understanding in skeletal muscle of the relative roles of various ECM proteins in providing passive muscle stiffness and show that the normal balance amongst extracellular matrix components of muscle is lost in cerebral palsy. In addition, these data may provide insights into t...

The history-dependence of force refers to the reduction or increase in force following active muscle shortening (residual torque depression; rTD) or lengthening (residual torque enhancement; rTE), respectively. It has been shown that rTE is maintained at the cellular level in conditions of reduced c...

The purpose of this study was to determine if alternative functional performance tests are able to detect between limb differences following ACL-R. Participants performed a chair to box test, lateral hurdle hop, single leg forward hop, and 30 second side hop test. The involved limb relative to the u...

The formation of a micro-damage process zone (MDPZ) ahead of cracks in cortical bone increases its fracture resistance. How extensive this MDPZ forms, is therefore vital to bone's fracture toughness. Using a continuum damage mechanics (CDM) approach, a finite element (FE) model was built to simulate...

The patellofemoral dysfunction (PFD) is commonly related to changes in dynamic stabilization of the knee, mainly during activities as descending stairs, where there is higher stress to the joint. The aim of this study was to angles during the step-down test in the healthy knee and the knee with PFD ...

When walking at similar speeds, greater positive hip extensor and/or flexor work is thought to compensate for lower positive ankle work during push-off in older versus young adults. Ankle moments contribute to positive ankle work in walking and are reduced in old age. We used induced acceleration an...

Using a novel rheological model of anterior cruciate ligament (ACL) loading, we estimated ACL force (FACL) in females during drop-land-cut and running manoeuvres, as well as the loading mechanism. In both tasks, peak loading occurred shortly following initial foot contact, but was larger during drop...