THE EFFECT OF SHOES ON KNEE KINETICS AND ANTERIOR TIBIAL TRANSLATION DURING SINGLE-LEG LANDING

The purpose of this study was to compare how knee kinematics and kinetics are influenced during single-leg landing in shod condition compared to barefoot condition. We hypothesized that the anterior tibial translation (ATT) and utilized coefficient of friction (uCoF) are greater in shod landing. Ten male subjects performed single-leg landing from a 0.3-m-high platform using their self-selected dominant lower limb under shod and barefoot condition. A force plate and a motion capture system were used for measuring ground reaction force and capturing kinematics data, respectively. The shod condition showed a significant higher ATT (p = 0.011) and uCoF (p = 0.022) at 30° flexion than barefoot condition. These findings would be considered as one of evidence that high shoe-surface friction increase ACL injury risks due to high ATT at extended knee position

Transition versus Continuous Slope Walking: Adaptation to Change Center of Mass Velocity in Young Men

During continuous uphill walking (UW) or downhill walking, human locomotion is modified to counteract the gravitational force, aiding or impeding the body’s forward momentum, respectively. This study aimed at investigating the center of mass (COM) and center of pressure (COP) velocities and their relative distance during the transition from uphill to downhill walking (UDW) to determine whether locomotor adjustments differ between UDW and UW. Fourteen participants walked on a triangular slope and a continuous upslope of 15°. The kinematics and COPs were obtained using a force plate and a motion capture system. The vertical velocity of the COM in the propulsion phase, the horizontal distance between the COM and COP at initial contact, and the duration of the subphases significantly differed between UDW and UW (all p<0.05). Compared with the results of UW, longer durations and the deeper downward moving COM in the propulsion phase were observed during UDW (all p<0.05). Additionally, a shorter horizontal distance between the COM and COP at initial contact was associated with a slower vertical COM velocity in the propulsion phase during UDW. The reduced velocity is likely a gait alteration to decrease the forward momentum of the body during UDW

Influence of individual quadriceps and hamstrings muscle architecture and quality on knee adduction and flexion moment in gait

Abstract The purpose of this study was to investigate the relationship between muscular parameters of quadriceps/hamstrings and knee joint kinetics in gait. Muscle architecture (thickness, pennation angle, and fascicle length), and quality (echo intensity) of individual quadriceps and hamstrings of 30 healthy participants (16 males and 14 females) was measured using ultrasound. Peak knee flexion moment (KFM), KFM impulse, peak knee adduction moment (KAM), and KAM impulse during walking were obtained at preferred speed. Pearson’s correlation coefficient and multiple regression analyses were performed at significance level of 0.05, and Cohen’s f 2 values were calculated to examine the effect sizes of multiple regression. The hamstring-to-quadriceps muscle thickness ratio (r = 0.373) and semitendinosus echo intensity (r =  − 0.371) were predictors of first peak KFM (R2 = 0.294, P = 0.009, f 2 = 0.42), whereas only vastus medialis (VM) echo intensity was a significant predictor of second peak KFM (r = 0.517, R2 = 0.267, P = 0.003, f 2 = 0.36). Only the VM thickness was the predictor of first (r = 0.504, R2 = 0.254, P = 0.005, f 2 = 0.34) and second peak KAM (r = 0.581, R2 = 0.337, P = 0.001, f 2 = 0.51), and KAM impulse (r = 0.693, R2 = 0.480, P < 0.001, f 2 = 0.92). In conclusion, the greater hamstring-to-quadriceps muscle thickness ratio and the muscle architecture and quality of medial quadriceps/hamstring play an important role in KFM and KAM, and may have implications in knee osteoarthritis

Deep Learning-Based Identification Algorithm for Transitions Between Walking Environments Using Electromyography Signals Only

Although studies on terrain identification algorithms to control walking assistive devices have been conducted using sensor fusion, studies on transition classification using only electromyography (EMG) signals have yet to be conducted. Therefore, this study was to suggest an identification algorithm for transitions between walking environments based on the entire EMG signals of selected lower extremity muscles using a deep learning approach. The muscle activations of the rectus femoris, vastus medialis and lateralis, semitendinosus, biceps femoris, tibialis anterior, soleus, medial and lateral gastrocnemius, flexor hallucis longus, and extensor digitorum longus of 27 subjects were measured while walking on flat ground, upstairs, downstairs, uphill, and downhill and transitioning between these walking surfaces. An artificial neural network (ANN) was used to construct the model, taking the entire EMG profile during the stance phase as input, to identify transitions between walking environments. The results show that transitioning between walking environments, including continuously walking on a current terrain, was successfully classified with high accuracy of 95.4 &#x0025; when using all muscle activations. When using a combination of muscle activations of the knee extensor, ankle extensor, and metatarsophalangeal flexor group as classifying parameters, the classification accuracy was 90.9 &#x0025;. In conclusion, transitioning between gait environments could be identified with high accuracy with the ANN model using only EMG signals measured during the stance phase

Biomechanical Effect of Coronal Alignment and Ligament Laxity in Total Knee Arthroplasty: A Simulation Study

The purposes of this study were to develop a cruciate-retaining total knee arthroplasty musculoskeletal model, which enables the adjustment of ligament length and implant alignment; validate the model; and evaluate the effects of varus/valgus alignment adjustment and unbalanced medial/lateral ligament laxity during gait. A cruciate-retaining total knee arthroplasty musculoskeletal model was constructed and validated against the in vivo contact forces. This model was transformed to 2 degrees varus/valgus alignment of femoral or tibial replacement models and 2 degrees medial/lateral laxity models. The contact forces and ligament tensions of the adjusted models were calculated. The contact forces in the model showed good agreement with the in vivo contact forces. Valgus replacement alignment with balanced ligament models showed a lower contact force at the medial compartment than at the neutral alignment model, whereas the varus replacement alignment with balanced ligament models showed a greater contact force at the medial compartment and medial/posterior cruciate ligament tension. The medial laxity with neutral alignment model showed a similar contact force with decreased medial ligament tension compared to the balanced neutral alignment model, whereas the lateral laxity with the neutral alignment model showed a greater contact force and decreased lateral ligament tension. The cruciate-retaining total knee arthroplasty model was validated using in vivo contact forces (r = 0.939) Two degrees of valgus alignment adjustment with balanced ligament or neutral alignment with 2 degrees of medial laxity can be safe without increasing contact force or ligament tension compared to neutral alignment with a balanced extension gap. However, 2 degrees of varus alignment adjustment with balanced ligament or neutral alignment with 2 degrees of lateral laxity may be unfavorable due to the overloading of the joints and knee ligaments.N

UV-LEDs for the disinfection and bio-sensing applications

UV-LEDs are used to generate ultraviolet (UV) light with high wall-plug efficiency. UV-LEDs have a unique character of generating a relatively narrow monochromatic UV wavelength band which makes them different from other conventional light sources. LEDs have lots of advantages in size, efficiency, lifetime, and low operating temperature. LEDs have been used for medical treatments but red-colored visible LEDs have been mainly used therein before the multi-color LED chip-on-board technologies become widely available. UV-LEDs now have wider range of applications in sterilization, sensing, and detection. This paper overviews currently available fabrication techniques and biomedical applications of UV-LEDs. In addition, the challenges and future developments for commercialization of UV-LEDs' bio-application are discussed