Medial-lateral Shear Research Articles

Complex Neck Loading and Injury Tolerance in Lateral Bending With Head Rotation From Human Cadaver Tests.

Advancements in automated vehicles may position the occupant in postures different from the current standard posture. It may affect human tolerance responses. The objective of this study was to determine the lateral bending tolerance of the head-cervical spine with initial head rotation posture using loads at the occipital condyles and lower neck and describe injuries. Using a custom loading device, head-cervical spine complexes from human cadavers were prepared with load cells at the ends. Lateral bending loads were applied to prerotated specimens at 1.5 m/s. At the occipital condyles, peak axial and antero-posterior and medial-lateral shear forces were: 316-954 N, 176-254 N, and 327-508 N, and coronal, sagittal, and axial moments were: 27-38 N·m, 21-38 N·m, and 9.7-19.8 N·m, respectively. At the lower neck, peak axial and shear forces were: 677-1004 N, 115-227 N, and 178-350 N, and coronal, sagittal, and axial moments were: 30-39 N·m, 7.6-21.3 N·m, and 5.7-13.4 N·m, respectively. Ipsilateral atlas lateral mass fractures occurred in four out of five specimens with varying joint diastasis and capsular ligament involvements. Acknowledging that the study used a small sample size, initial tolerances at the occipital condyles and lower neck were estimated using survival analysis. Injury patterns with posture variations are discussed.

Evaluation of in-shoe plantar pressure and shear during walking for diabetic foot ulcer prevention.

To investigate reliability and changes of in-shoe plantar pressure and shear during walking at three cadences with two insole designs. This was a precursor to the investigation of plantar loading in people with diabetes for potential foot ulcer prevention. A sensorised insole system, capable of measuring plantar pressure and shear at the heel, fifth metatarsal head (5MH), first metatarsal head (1MH) and hallux, was tested with ten healthy participants during level walking. Reliability was evaluated, using intra-class correlation coefficient (ICC), while varying the cadences and insole types. Percentage changes in pressure and shear relative to values obtained at self-selected cadence with a flat insole design were investigated. Mean±standard deviation of maximum pressure, medial-lateral and anterior-posterior shear of up to 380±24kPa, 46±2kPa and -71±4kPa, respectively, were measured. The ICC in ranges of 0.762-0.973, 0.758-0.987 and 0.800-0.980 were obtained for pressure, anterior-posterior and medial-lateral shear, respectively. Opposite anterior-posterior shear directions between 5MH and 1MH (stretching), and between 1MH and hallux (pinching) were observed for some participants. Increasing cadence increased pressure and anterior-posterior shear (by up to +77%) but reduced medial-lateral shear at the heel and hallux (by up to -34%). Slower cadence increased anterior-posterior shear (+114%) but decreased medial-lateral shear (-46%) at the hallux. The use of a flexible contoured insole resulted in pressure reduction at the heel and 5MH but an increase in anterior-posterior shear at the heel (+69%) and hallux (+75%). The insole system demonstrated good reliability and is comparable to reported pressure-only systems. Pressure measurements were sensitive to changes in cadence and insole designs in ways that were consistent with the literature. However, our plantar shear showed localised shear changes with cadences and insoles for the first time, as well as stretching and pinching effects on plantar tissue. This opens new possibilities to investigate plantar tissue viability, loading characteristics and orthotic designs aimed towards foot ulcer prevention.

Poster 128: The Effect of Meniscotibial Ligament Disruption and Repair on Posterior Medial Meniscal Root Forces

Objectives: Meniscal injuries occur in as many as 1% of active people, and while outcomes for tears at the posterior medial meniscal root (PMMR) are well cited, the risk factors for injury have room for greater understanding. Incidence of disruption to the meniscotibial ligament (MTL) is correlated to occurrence of PMMR tears, suggesting that disruption to the MTL may increase forces at the PMMR and put the PMMR at greater risk of injury. The effect of an MTL disruption and repair on three-dimensional forces at the PMMR is unknown. The purpose of this study was to determine if MTL insufficiency alters forces at the PMMR., if a tenodesis procedure can restore PMMR forces to that of an MTL intact state, and to determine how knee flexion angle impacts PMMR root forces in the MTL intact and cut states. We hypothesize that all shear forces will increase following MTL disruption. Methods: Ten fresh-frozen cadaveric knees (Average age: 53.2 years) were tested in three conditions (Intact, MTL Cut, MTL Tenodesis). Specimens were dissected down to the knee capsule with ligaments intact. A 3D load cell construct (Figure 1) was installed inside the tibia such that 3D forces of the PMMR could be measured when the joint was loaded. Each specimen was mounted to a materials testing machine (Instron) via a custom fixture that allowed the specimen flexion angle to be changed in 30 degree increments. The specimen was first loaded to 500 N of compression with 0 N-m of torque, then to 5 N-m of internal torque with 50 N of compression, and finally to 5 N-m of external torque with 50 N of compression. 3D forces at the PMMR were recorded for all loading sequences, and the process was repeated for each flexion angle (0°, 30°, 60°, and 90°). PMMR forces along each axis (compression- tension, anterior-posterior shear, and medial-lateral shear) were compared across MTL testing states across flexion angles using linear mixed modelling. Results: When the joint was loaded in compression, MTL Cut state significantly increased compression of the PMMR (p = 0.0368), and the Tenodesis state did not significantly restore tension-compression forces of the PMMR (Intact→Tenodesis: p = 0.008)(Figure 1). When the joint was loaded in external rotation, the MTL Cut State significantly increased compression (p < 0.0001), significantly decreased anterior shear (p = 0.0003), and, in high flexion angles, significantly decreased ML shear forces of the PMMR (Figure 1). The Tenodesis state did not significantly restore tension-compression (Intact→Tenodesis: p < 0.0001) or AP forces (Intact→Tenodesis: p = 0.0002) of the PMMR (Figure 1). Conclusions: The key finding of this study is that MTL disruption increases compression forces and decreases AP shear forces seen at the root when the joint is loaded in compression and external rotation. These findings indicate that the intact MTL protects the PMMR from compression and shear loads during movements where the joint is loaded in compression and external rotation, movements that are clinically reported to put the knee joint at risk of PMMR injury. The authors believe these relationships are observed because the MTL may play a role in maintaining meniscal hoop stresses, which converts joint compression loads into tension and shear forces along the meniscal attachment points. When the MTL is disrupted, the other meniscal attachment points, the PMMR included, see elevated compression loads as a result. This is the first study to measure 3D forces at the PMMR, a necessary capability to assess PMMR injury risk. It is notable that the tenodesis procedure performed in this study did not restore PMMR forces. Future studies should develop improved centralization or tenodesis procedures to better restore PMMR forces and decrease likelihood for PMMR injury after MTL disruption.

Development of a Full Flexion 3D Musculoskeletal Model of the Knee Considering Intersegmental Contact During High Knee Flexion Movements.

A musculoskeletal model of the right lower limb was developed to estimate 3D tibial contact forces in high knee flexion postures. This model determined the effect of intersegmental contact between thigh-calf and heel-gluteal structures on tibial contact forces. This model includes direct tracking and 3D orientation of intersegmental contact force, femoral translations from in vivo studies, wrapping of knee extensor musculature, and a novel optimization constraint for multielement muscle groups. Model verification consisted of calculating the error between estimated tibial compressive forces and direct measurements from the Grand Knee Challenge during movements to ∼120° of knee flexion as no high knee flexion data are available. Tibial compression estimates strongly fit implant data during walking (R2 = .83) and squatting (R2 = .93) with a root mean squared difference of .47 and .16 body weight, respectively. Incorporating intersegmental contact significantly reduced model estimates of peak tibial anterior-posterior shear and increased peak medial-lateral shear during the static phase of high knee flexion movements by an average of .33 and .07 body weight, respectively. This model supports prior work in that intersegmental contact is a critical parameter when estimating tibial contact forces in high knee flexion movements across a range of culturally and occupationally relevant postures.

Anterior cruciate ligament deficiency combined with lateral and/or medial meniscal injury results in abnormal kinematics and kinetics during level walking.

Anterior cruciate ligament injuries are commonly combined with meniscal tears. This study was performed to analyze the kinematics and kinetics of knees with anterior cruciate ligament deficiency with or without a combined medial or/and lateral meniscal injury during level walking. In all, 29 patients with unilateral anterior cruciate ligament deficiency and 15 healthy male volunteers were recruited. Among these patients, 12 had isolated unilateral anterior cruciate ligament injuries (ACLD group), 5 had combined anterior cruciate ligament and lateral meniscal injuries (ACLDL group), 5 had combined anterior cruciate ligament and medial meniscal injuries (ACLDM group), and 7 had combined anterior cruciate ligament and medial/lateral meniscal injuries (ACLDML group). A subject-specific musculoskeletal multibody dynamics model was utilized to estimate the tibiofemoral joint kinematic and kinetic behaviors based on the experimental data measured by using an optical tracking system. Regardless of the presence or absence of meniscal injury, the knees with anterior cruciate ligament deficiency exhibited significantly less extension than the control knees at the terminal stance (range of extension: ACLD, 4.84° ± 4.31°; ACLDL, 6.65° ± 5.73°; ACLDM, 5.21° ± 4.77°; ACLDML, 6.91° ± 4.30°; control, 12.35° ± 5.52°; P < 0.05). A lower extension moment and adduction moment in all anterior cruciate ligament deficiency affected knees were detected during the terminal stance when compared with control knees (P < 0.05). The ACLDML group showed significantly lower proximal-distal compressive forces and anterior-posterior shear forces (approximately 0.5-1.5 body weight; P < 0.05) compared to the other 4 groups, while the anterior-posterior and medial-lateral shear forces tended to increase in the ACLD, ACLDL, and ACLDM groups at the mid to terminal stance. Significant lower adduction-abduction and internal-external moment peaks were observed in ACLDML groups, but not in the ACLD, ACLDL and ACLDM groups. These results indicate that the combination of an anterior cruciate ligament injury and meniscal injury could alter the kinematics and kinetics of anterior cruciate ligament deficiency affected knees depending on the presence and type of the meniscal tear.

Evaluation of compressive and shear joint forces on medial and lateral compartments in knee joint during walking before and after medial open-wedge high tibial osteotomy

The main principle of open-wedge high tibial osteotomy (HTO) is to shift the weight-bearing line of the knee joint in order to decompress the degenerated compartment and delay osteoarthritis (OA). In this study, the resultant contact forces on the medial compartment, lateral compartment, and total tibiofemoral joint were analyzed during gait for five OA patients before and after HTO in order to fully understand the effect and mechanism of HTO for the OA knee. The compressive, lateral-medial shear, and anteriorposterior shear force components of the joint force, as well as the ratio of the medial contact force to the lateral contact force, were investigated using inverse dynamic and multi-body dynamic models. Medial open-wedge HTO improved the balance of medial and lateral contact forces on the tibiofemoral joint, which demonstrated the purpose of HTO provided by clinical studies and the outcomes of a computational study. In addition to the compressive contact force, the lateral-medial shear force was also reduced during the stance phase of walking after HTO. The technology in this study provides a fundamental tool to evaluate the outcomes of HTO by considering daily and sports activities.

The effect of ankle bracing on knee kinetics and kinematics during volleyball‐specific tasks

The purpose of this study was to examine the effects of ankle bracing on knee kinetics and kinematics during volleyball tasks. Fifteen healthy, elite, female volleyball players performed a series of straight-line and lateral volleyball tasks with no brace and when wearing an ankle brace. A 14-camera Vicon motion analysis system and AMTI force plate were used to capture the kinetic and kinematic data. Knee range of motion, peak knee anterior-posterior and medial-lateral shear forces, and peak ground reaction forces that occurred between initial contact with the force plate and toe off were compared using paired sample t-tests between the braced and non-braced conditions (P < 0.05). The results revealed no significant effect of bracing on knee kinematics or ground reaction forces during any task or on knee kinetics during the straight-line movement volleyball tasks. However, ankle bracing was demonstrated to reduce knee lateral shear forces during all of the lateral movement volleyball tasks. Wearing the Active Ankle T2 brace will not impact knee joint range of motion and may in fact reduce shear loading to the knee joint in volleyball players.

Injury Thresholds of Knee Ligaments Under Lateral–Medial Shear Loading: An Experimental Study

Objective: Knee ligament injuries frequently cause devastating impairment to the injured. In car–pedestrian impact accidents, lateral–medial shear displacement is one of principal mechanisms of knee ligament injuries. The current study aims to investigate injury thresholds of knee ligaments under lateral–medial shear loading to improve pedestrian safety. Methods: Ten isolated human knee joints without surrounding muscles were tested under dynamic lateral–medial shear loading in 2 groups: 3 left knee joints were tested in the shearing of medial tibial translation, and other knee joints were tested in lateral tibial translation. Based on combined analysis of experimental videos and force curves, the primary failure time of knee ligaments and the corresponding shear displacement were determined. Results: Under lateral tibial translation and medial tibial translation, both primary injury types of knee ligaments and force curves showed essential differences. It appears that the majority of primary failure modes were anterior cruciate ligament (ACL) injury when the tibia was displaced medially and posterior cruciate ligament (PCL) injury when the tibia was displaced laterally. Overall experimental results indicated that the injury threshold of the knee joint under lateral–medial shear loading varied from 11.4 to 17.6 mm, with an average level approximately 14.3 mm. Conclusion: Based on the bone–ligament–bone complex experiment of the knee, we present injury occurrences of the knee joints in lateral and medial shear loading. The testing data provide a basis for improving knee injury criteria that regulate passenger cars to reduce their aggressiveness to pedestrians. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.

Internal femoral forces and moments during running: Implications for stress fracture development

Background Femoral stress fractures tend to occur at the neck, medial proximal-shaft, and distal-shaft. The purpose of this study was to determine the internal femoral forces and moments during running. It was expected that larger loads would occur at these common sites of femoral stress fracture. Methods Ten subjects ran at their preferred running speed over a force platform while motion capture data were collected. Static optimization in conjunction with a SIMM musculoskeletal model was used to determine individual muscle forces of the lower extremity. Joint contact forces were determined, and a quasi-static approach was used to calculate internal forces and moments along a centroid path through the femur. Findings The largest mean peak loads were observed at the following regions: anterior–posterior shear, 7.47 bodyweights (BW) at the distal-shaft (posteriorly directed); axial force, 11.40 BW at the distal-shaft (compression); medial–lateral shear, 3.75 BW at the neck (medially directed); anterior–posterior moment, 0.42 BW m at the proximal-shaft (medial surface compression); torsional moment, 0.20 BW m at the distal-shaft (external rotation); medial–lateral moment, 0.44 BW m at the distal-shaft (anterior surface compression). Interpretation The mechanical loading environment of the femur during running appears to explain well the redundancy in femoral stress fracture location. We observed the largest internal loads at the three femoral sites prone to stress fracture.

The effect of internal and external foot rotation on the adduction moment and lateral–medial shear force at the knee during gait

It has been hypothesised that those with medial compartment knee osteoarthritis tend to externally rotate their foot during gait in order to unload the diseased compartment. This has been found to decrease the adduction moment at the knee during late stance, although the effects of foot rotation on shear forces at the knee have not yet been determined. Also, the effects of internal foot rotation on the knee during gait are not clear. This study performed a gait analysis on 11 healthy participants (M: 6; mean age 22.9+/-1.8 years) in three conditions: (1) natural foot rotation position; (2) internal foot rotation and (3) external foot rotation. Three-dimensional gait analysis calculated the knee adduction moment and lateral-medial shear force for all three foot rotation conditions. Internal rotation of the foot increased the knee adduction moment and lateral-medial shear force magnitude during late stance, while external rotation of the foot decreased the magnitude of both these measures. This implies that walking with an externally and internally rotated foot may unload the diseased compartment for those with medial and lateral compartment knee OA, respectively. Also, the relationship of foot rotation angle to the adduction moment and lateral-medial shear force was strengthened when data were corrected for the subject's normal walking condition. Knee OA subject data revealed that they were able to reduce the knee adduction moment more than normal subjects during late stance, indicating that other factors besides the rotation of the foot need to be investigated.

Surgical Treatment of Non-septic Non-unions of the Humeral Shaft. A Biomechanical Study

To compare the firmess and stress distribution patterns in the implants of two experimental models: a humerus with shaft pseudoarthrosis stabilized with a plate, and a humerus with shaft nonunions stabilized with a locking nail. The two fixation devices are attached to cadaver humerus bones; geometries are created with the CATIA 4.2 design software (IBM, Armonk, USA). Subsequently, these geometries were modelled with the MSC PATRAN® computer processor (IBM, Armonk, USA). Finally, the mechanical properties of the materials were established as well as the contour properties and the loads the models were subjected to. The nailed model was firmer that the plated model as regards compression, traction and torsion. Nonetheless, as far as A/P and lateral-medial flexion and lateral-medial shear stresses were concerned, the plated model was firmer than the nailed model. Stress distribution was more heterogeneous in the nail than in the plate, the latter being the implant type supporting the highest stress levels in all the loading phases studied. For some stress levels, the nail proved to be more stable than the plate, although for other stress levels the opposite was the case. In any case, the nail provides a better stress distribution than the plate. Comparar la rigidez y la distribución de tensiones en los implantes de dos modelos experimentales: un húmero con pseudoartrosis diafisaria estabilizado con placa y un húmero con pseudoartrosis diafisaria estabilizado con clavo encerrojado. Con un húmero de cadáver y los dos dispositivos de fijación se crearon las geometrías con el programa de diseño CATIA v4.2® (IBM, Armonk, USA). Posteriormente estas geometrías se modelaron con el preprocesador informático MSC-PATRAN® (IBM, Armonk, USA). Finalmente se establecieron las propiedades mecánicas de los materiales, las condiciones de contorno y las cargas a las que fueron sometidos los modelos. El modelo con clavo fue más rígido que el modelo con placa a compresión, tracción y torsión, sin embargo, el modelo con placa fue más rígido que el modelo con clavo en flexión anteroposterior, lateromedial y cizallamiento lateromedial. La distribución de tensiones ha sido más heterogénea en el clavo que en la placa, siendo esta última el implante que soporta los mayores valores tensionales en todos los estados de carga estudiados. La rigidez del modelo experimental depende no solo del implante sino del estado de carga aplicado, siendo superior el clavo en unas condiciones de carga y la placa en otras. El clavo sin embargo, absorbe menos tensión que la placa en todos los estados de carga estudiados.

The Effect Of Foot Progression Angle On Knee Joint Loads During Gait

The mechanical loads placed on the knee during gait, in particular the adduction moment (KAM), have been implicated in the progression of knee osteoarthritis (OA). Those presenting with symptomatic medial compartment knee OA tend to adopt a toe out gait pattern reducing the peak KAM during gait, hence unloading the diseased medial compartment. Although this is known, the relationship between the foot progression angle (FPA) and the KAM, along with other knee gait kinetic measures has yet to be determined. PURPOSE To determine the relationship between FPA and 3D knee gait forces and moments. METHODS Gait analysis was performed on 11 healthy subjects (23 +/− 1.7 yrs). Subjects performed five trials in each of three conditions: natural foot position (NFP), approximately 30 degrees internally rotated (IR) and approximately 30 degrees externally rotated (ER) from their natural position. 3D knee joint forces and moments were compared to true FPA (ANOVA) and a regression analysis determined the relationships between normalized (by NFP) values. RESULTS Late stance peak KAM and medial-lateral shear forces (MLF) were significantly different across conditions, (KAM: ER=0.125, NFP=0.267, IR=0.410 Nm/kg; p<0.01 and MLF: ER=−0.980, NFP=−1.248, IR=−1.447 N/kg; p<0.01). See Figure 1 for average gait curves. There were also strong relationships between changes in FPA (actual range of 49.3 ±) and changes in KAM (R2=.97) and MLF (R2=.88).FigureCONCLUSIONS Results suggest that for every 10 degree change in FPA there is a 21.7% change in KAM and a 7.6% change in MLF during late stance. This may have implications in preventing the development and progression of knee OA.

The Effect Of Foot Progression Angle On Knee Joint Loads During Gait

The mechanical loads placed on the knee during gait, in particular the adduction moment (KAM), have been implicated in the progression of knee osteoarthritis (OA). Those presenting with symptomatic medial compartment knee OA tend to adopt a toe out gait pattern reducing the peak KAM during gait, hence unloading the diseased medial compartment. Although this is known, the relationship between the foot progression angle (FPA) and the KAM, along with other knee gait kinetic measures has yet to be determined. PURPOSE To determine the relationship between FPA and 3D knee gait forces and moments. METHODS Gait analysis was performed on 11 healthy subjects (23 +/− 1.7 yrs). Subjects performed five trials in each of three conditions: natural foot position (NFP), approximately 30 degrees internally rotated (IR) and approximately 30 degrees externally rotated (ER) from their natural position. 3D knee joint forces and moments were compared to true FPA (ANOVA) and a regression analysis determined the relationships between normalized (by NFP) values. RESULTS Late stance peak KAM and medial-lateral shear forces (MLF) were significantly different across conditions, (KAM: ER=0.125, NFP=0.267, IR=0.410 Nm/kg; p<0.01 and MLF: ER=−0.980, NFP=−1.248, IR=−1.447 N/kg; p<0.01). See Figure 1 for average gait curves. There were also strong relationships between changes in FPA (actual range of 49.3 ±) and changes in KAM (R2=.97) and MLF (R2=.88).FigureCONCLUSIONS Results suggest that for every 10 degree change in FPA there is a 21.7% change in KAM and a 7.6% change in MLF during late stance. This may have implications in preventing the development and progression of knee OA.

Classification of mobile-bearing knee designs: mobility and constraint.

Restoration of normal knee joint function through surgical reconstruction is dependent upon load-sharing between the implant and the surrounding soft-tissue structures. Mobile-bearing knee designs offer the advantage of maximally conforming geometry while diminishing constraint forces to fixation interfaces through plateau mobility. The degree of mobility afforded by these designs in the anterior-posterior, medial-lateral, and rotational directions defines the required interaction between the soft tissues and the design geometry to maintain a stable articulation. This study characterizes nine contemporary mobile-bearing designs in terms of the force generated during a prescribed displacement. Among the designs evaluated, only the LCS Deep Dish Rotating Platform is available for clinical use in the United States. A dynamic testing system capable of applying biaxial loads (Instron Testing Machine, model 1115; Instron, Canton, Massachusetts) was utilized to assess the intrinsic performance characteristics of nine non-hinged, mobile-bearing knee designs. Anterior, posterior, medial, lateral, and rotational constraints were determined for each total knee design under a compressive load consistent with normal walking gait1,2. A compressive load of four times body weight and 0° of flexion was chosen to represent a position of gait where maximum shear forces act in the posterior and lateral directions as well as in rotation1,2. Anterior and medial shear forces are presented at the same gait position for completeness. A body weight of 163 lb (74 kg), which corresponds to the average for a sixty-year-old, 5-ft, 8-in (172.7-cm) male subject, was used in this evaluation3. ### Anterior-Posterior and Medial-Lateral Shear Testing Three tibial inserts were evaluated in each test direction for each system. Under the prescribed in vivo compressive load (652 lbf), shearing displacements were applied to the system until the implant subluxated (Fig. 1). Anterior, posterior, medial, and lateral subluxation was defined as the dislocation of the tibial component relative …

An optoelectric plantar "shear" sensing transducer: design, validation, and preliminary subject tests.

A prototype miniature plantar shear sensing transducer was developed, characterized, and tested in this study. Electro-optical components were chosen for the design because of the fast response time, low cost, small size, low power requirements, and adaptability to this application. The optoelectric circuit employed a 660 nm wavelength light source and photodiode solar cell. Signal amplification and sensitivity were adjusted to provide an output voltage proportional to light power. The sensor shell was designed to encapsulate the electro-optical sensing components while providing mechanical resistance to shear through a spring mechanism. A naval bronze was chosen for the shell due to its strength and nonreflective characteristics (alloy of copper and tin). Static and dynamic characteristics of the shear sensor were determined through a series of calibration tests. Mechanical crosstalk sensitivity ranged from 14.34 to 30.51 mV/N. This represented 1% full-scale/Newton sensitivity. Nonlinearity averaged 5.6% in the forward direction and 7.6% in the reverse direction. Overall sensor output hysteresis was 1.1 +/- 3.1% while the natural frequency of the sensor to an input shear transient was approximately 5 Hz. Temperature sensitivity was -7.0 mV/degree C or 3.5% full-scale/degree C. Testing of five adult subjects revealed peak anterior-posterior shear ranging from 6.7 kPa (posterior heel) to 51.4 kPa (great toe) and medial-lateral shear ranging from 5.4 kPa (great toe) to 43.5 kPa (first metatarsal head). Stress-time integral values ranged from 0.78 kPa-sec (posterior shear at the posterior heel) to 37.3 kPa-sec (medial shear at the posterior heel). Contact durations ranged from 0.28 sec (posterior shear at the posterior heel) to 1.25 sec (medial shear at the posterior heel). Further application of the sensor for plantar shear characterization in able-bodied subjects and those with pathology is suggested.