Evaluating Electromyography and Sonomyography Sensor Fusion to Estimate Lower-Limb Kinematics Using Gaussian Process Regression.

Research on robotic lower-limb assistive devices over the past decade has generated autonomous, multiple degree-of-freedom devices to augment human performance during a variety of scenarios. However, the increase in capabilities of these devices is met with an increase in the complexity of the overall control problem and requirement for an accurate and robust sensing modality for intent recognition. Due to its ability to precede changes in motion, surface electromyography (EMG) is widely studied as a peripheral sensing modality for capturing features of muscle activity as an input for control of powered assistive devices.

Effect of Neuromuscular Electrical Stimulation During Walking on Pain Sensitivity in Women With Obesity With Knee Pain: A Randomized Controlled Trial.

Objective: To assess the extent to which pain sensitivity is altered in women with obesity with frequent knee symptoms who walk with either a hybrid training system (HTS) that provides antagonist muscle electrical stimulation vs sensory transcutaneous electrical nerve stimulation (TENS).

Design: Randomized, double-blinded, controlled trial.

Setting: University-based fitness center.

Ultrasound-Derived Features of Muscle Architecture Provide Unique Temporal Characterization of Volitional Knee Motion.

Sonomyography, or dynamic ultrasound imaging of skeletal muscle, has gained significant interest in rehabilitation medicine. Previously, correlations relating sonomyography features of muscle contraction, including muscle thickness, pennation angle, angle between aponeuroses and fascicle length, to muscle force production, strength and joint motion have been established. Additionally, relationships between grayscale image intensity, or echogenicity, with maximum voluntary isometric contraction of muscle have been noted.

Performance of Sonomyographic and Electromyographic Sensing for Continuous Estimation of Joint Torque During Ambulation on Multiple Terrains.

Advances in powered assistive device technology, including the ability to provide net mechanical power to multiple joints within a single device, have the potential to dramatically improve the mobility and restore independence to their users. However, these devices rely on the ability of their users to continuously control multiple powered lower-limb joints simultaneously. Success of such approaches rely on robust sensing of user intent and accurate mapping to device control parameters.

Longitudinal Relationship Between Tibiofemoral Contact Stress at Baseline and Worsening of Knee Pain Over 84 Months in the Multicenter Osteoarthritis Study.

Objective: The aim of the study was to determine whether tibiofemoral contact stress predicts risk for worsening knee pain over 84 ms in adults aged 50-79 yrs with or at elevated risk for knee osteoarthritis.

Design: Baseline tibiofemoral contact stress was estimated using discrete element analysis. Other baseline measures included weight, height, hip-knee-ankle alignment, Kellgren-Lawrence grade, and Western Ontario and McMaster Universities Osteoarthritis Index pain subscale.

Ultrasound Sensing Can Improve Continuous Classification of Discrete Ambulation Modes Compared to Surface Electromyography.

Clinical translation of "intelligent" lower-limb assistive technologies relies on robust control interfaces capable of accurately detecting user intent. To date, mechanical sensors and surface electromyography (EMG) have been the primary sensing modalities used to classify ambulation. Ultrasound (US) imaging can be used to detect user-intent by characterizing structural changes of muscle.

Use of Sonomyographic Sensing to Estimate Knee Angular Velocity During Varying Modes of Ambulation.

Ultrasound (US) imaging of muscle has been introduced as a promising sensing modality for assistive device control. Ten able-bodied subjects completed level, incline and decline walking on a treadmill in a motion capture laboratory while wearing reflective markers on upper- and lower-body. A wearable US transducer was affixed to subjects' anterior thigh, and time-intensity features were extracted from transverse US images of the knee extensor muscles.

Ultrasound Features of Skeletal Muscle Can Predict Kinematics of Upcoming Lower-Limb Motion.

Seamless integration of lower-limb assistive devices with the human body requires an intuitive human-machine interface, which would benefit from predicting the intent of individuals in advance of the upcoming motion. Ultrasound imaging was recently introduced as an intuitive sensing interface. The objective of the present study was to investigate the predictability of joint kinematics using ultrasound features of the rectus femoris muscle during a non-weight-bearing knee extension/flexion.

The Association of Parity with Greater Dynamic Pronation of the Feet.

Background: Postpartum women are at increased risk for lower limb musculoskeletal disorders. Foot arch collapse following pregnancy has been reported as a mechanism for this increased risk. However, dynamic changes during gait in postpartum women have not been reported.

The Relationship of Three-Dimensional Joint Space Width on Weight Bearing CT With Pain and Physical Function.

Limitations of plain radiographs may contribute to poor sensitivity in the detection of knee osteoarthritis and poor correlation with pain and physical function. 3D joint space width, measured from weight bearing CT images, may yield a more accurate correlation with patients' symptoms. We assessed the cross-sectional association between 3D joint space width and self-reported pain and physical function.

The Effect of Neuromuscular Electrical Stimulation During Walking on Muscle Strength and Knee Pain in Obese Women With Knee Pain: A Randomized Controlled Trial.

Objective: The aim of the study was to assess the effectiveness of a hybrid training system with walking that simultaneously applies electrical stimulation to the knee extensors/flexors during walking in obese women with knee pain.

Design: This is a randomized, single-blind (assessor), controlled trial. Twenty-eight obese women with knee pain were randomized to 12 weeks of biweekly walking with either hybrid training system with walking or with transcutaneous electrical nerve stimulation (control).

Gait Phase Identification During Level, Incline and Decline Ambulation Tasks Using Portable Sonomyographic Sensing.

Clinical viability of powered lower-limb assistive devices requires reliable and intuitive control strategies. Stance and swing are the main phases of the gait cycle across different locomotion tasks. Hence, a reliable method to accurately identify these phases can decrease sensing complexity and assist in enabling high-level control of assistive devices.

Is muscle strength in a painful limb affected by knee pain status of the contralateral limb? - Data from the Osteoarthritis Initiative.

Contralateral knee pain has been suggested to be associated with muscle weakness in a pain-free knee, potentially through a mechanism of central nervous inhibition. Whether contralateral knee pain also affects muscle strength in a painful knee, however, is unknown. Here we study the extent to which isometric muscle strength differs between matched painful limbs of people with unilateral knee pain vs.

Evaluation of the Combined Application of Neuromuscular Electrical Stimulation and Volitional Contractions on Thigh Muscle Strength, Knee Pain, and Physical Performance in Women at Risk for Knee Osteoarthritis: A Randomized Controlled Trial.

Background: Knee osteoarthritis (OA) is a leading cause of disability that is associated with quadriceps weakness. However, strengthening in people with or with risk factors for knee OA can be poorly tolerated.

Objective: To assess the efficacy of a 12-week low-load exercise program, using a hybrid training system (HTS) that uses the combination of neuromuscular electrical stimulation and volitional contractions, for improving thigh muscle strength, knee pain relief, and physical performance in women with or with risk factors for knee OA.

The Effect of Arch Drop on Tibial Rotation and Tibiofemoral Contact Stress in Postpartum Women.

Background: Women are at greater risk for knee osteoarthritis and numerous other lower limb musculoskeletal disorders. Arch drop during pregnancy and the resultant excessive pronation of the feet may alter loading patterns and contribute to the greater prevalence of knee osteoarthritis in women.

Objective: To determine the effect of arch drop on tibial rotation and tibiofemoral contact stress.