Effects of an 8-week cadence gait training program on knee loading in individuals following ACL reconstruction

While normalization of gait is a primary goal of early rehabilitation, between limb asymmetries in knee extensor moment can persist 6-24 months later and previous literature assessing gait interventions is limited. The purpose of this study was to assess the influence of subject-specific cadence gait training program on knee loading mechanics following ACLr. Nine individuals completed an 8-week cadence training program (20min, 3x/week; Table1) and nine sex- and surgery-matched individuals served as controls. All eighteen participants received standard physical therapy and were tested at 1 and 3 months post-op. Kinematic and kinetic data were collected during walking at a self-selected speed. Repeated measures ANOVAs were used for comparisons; significance α≤0.05. Main effects of limb and time were observed: knee ROM (kROM;p<0.001;p=0.044;Fig.1) and knee extensor moment (kEXT;p=0.003;p=0.002) in the cadence and control groups, respectively. No main effects of group for kROM (p=0.136) or kEXT (p=0.229) were found. A trend toward a significant group x time x limb interaction was observed in kEXT (p=0.092), but not kROM (p=0.412). Post-hoc analyses of kEXT (Fig.2) revealed a significant time x limb interaction for the cadence group (p=0.053) but not the control group (p=0.884). In the cadence group, the time x limb interaction was driven by a 131% increase in kEXT in the surgical limb versus a 42% increase in the non-surgical limb between T1 and T2. Consistent with previous findings, these pilot data show promising results as the cadence intervention resulted in improvements in sagittal plane knee loading compared to controls.

Listed In: Biomechanics, Gait, Orthopedic Research, Physical Therapy, Sports Science

Spatiotemporal gait parameters are affected by footwear stiffness in toddler-aged children.

Footwear plays a significant role in, and can influence children’s gait. Footwear type is especially important as a child grows and develops from a novice to an expert walker. Compared to barefoot walking, children generally have increased spatiotemporal (ST) gait parameters while walking with footwear. Gait variability has also shown to be affected by footwear. The degree of stiffness in footwear could have a large influence on children’s gait and variability. This study investigated effects of footwear stiffness on ST gait parameters and gait variability in novice walkers. Children with an average age of 33.3 ( 7.0) months participated in a single data collection. Heel and toe marker positions were acquired for one minute of walking per condition. Participants walked on the treadmill in three levels of footwear stiffness (rigid: hard-soled stiff shoe, semi-rigid: EVA sole athletic shoe, compliant: moccasin soft-sole shoe) and barefoot. ST gait parameters and gait variability were calculated for each condition using marker. and treadmill forces. ST parameters all increased in the rigid and semi-rigid footwear conditions compared to soft-sole and barefoot. Interestingly, there were no differences between barefoot and wearing a moccasin for any of the ST variables. There were no differences in SD and COV between any of the footwear conditions. The moccasin shoe promotes walking most similar to normal barefoot walking. Standard measures of variability failed to detect differences between footwear conditions. Further investigation into different measurements is necessary to parse out what effect footwear has on children’s gait variability.
Listed In: Biomechanics, Gait

Pushoff Work is Increased Following Prosthesis Adaptation

The purpose of this study was to quantify adaptation to a new prosthesis in terms of mechanical work profiles. Currently, there is a lack of knowledge on how individuals adapt to a new prosthesis, with many studies investigating different prosthetic feet but not adaptation over time. Thus, there is a need for objective measures to quantify the process of adaptation. Mechanical power and work profiles are a prime subject for modern energy-storage-and-return type prostheses, as the amount of energy a prosthesis stores and returns (i.e., positive and negative work) during stance is directly related to how a user loads and unloads the limb. 22 individuals with unilateral, transtibial amputation were given a new prosthesis at their current mobility level (K3 or above) and wore it for a three-week adaptation period. Kinematic and kinetic measures were recorded from walking on overground force plates at 0, 1.5, and 3 weeks into the adaptation period. Positive and negative work done by the prosthesis and intact ankle-foot was calculated using a unified deformable segment model. Positive work from the prosthesis side increased by 6.1% and intact side by 5.7% after 3 weeks (p = .041, .036). No significant changes were seen in negative power from prosthesis or intact side (p = .115, .192). Analyzing work done by a prosthesis may be desirable for tracking a patient’s gait rehabilitation over time. Future work may analyze how mechanical work profiles relate to more traditional clinical measures.

Listed In: Biomechanics, Gait, Physical Therapy


INTRODUCTION Running-related injuries are most often single-sided and are partially attributed to lower limb movement and loading asymmetries. For example, runners with tibial stress fractures demonstrate asymmetry in loading rate. Running is a dynamic athletic event in which runners often engage in both inclined and declined running with the goal of improving conditioning. Symmetry Angle (SA) is a commonly used, robust measure of determining symmetry. The purpose of this study was to compare peak vertical ground reaction force (VGRF) symmetry using the SA during uphill, level and downhill running on an instrumented treadmill. METHODS Eleven healthy adults volunteered to participate in this study and running at 2.7 m/s at grades of 0°, 5.74° incline and 5.74° decline were analyzed. SA was computed using the peak VGRF values from both the limbs. RESULTS AND DISCUSSION No statistically significant differences in SA were observed between the three running conditions. (p=0.61) The unexpected uniformity in vertical GRF across uphill, level, and downhill running is consistent with the absence of changes in the peak magnitudes of the GRF observed previously. This suggests that neither moderate uphill or downhill running result in increases in peak GRF that may be considered injurious. CONCLUSIONS This was the first study that looked at kinetic symmetry using peak GRF in healthy recreational runners during the three running conditions. This study suggested that uphill and downhill running does not contribute to potential differences in interlimb symmetry and could be considered as a safe alternative to level running on a treadmill.
Listed In: Biomechanics, Gait

Prolonged Cycling&#039;s Effect on Transition Run Mechanics in Triathletes

A period of incoordination and fatigue is commonly associated with the transition run in triathletes, in which running mechanics are thought to be altered. Few studies have examined the changes in ground reaction forces and vertical loading rate during the transition run. Our purpose was to assess the changes that occur in ground reaction forces during a fatigued transition run in triathletes. 13 recreational male triathletes (34 ± 4.2 years) performed an incremental cycling test and a cycle to run transition on separate testing sessions. A 15-camera Vicon motion capture system collecting at 200 Hz and an AMTI force instrumented treadmill collecting at 2000 Hz were used in conjunction with a modified Plug-In Gait marker to collect trajectory and analog data for pre and post-cycling running trials. Ground reaction forces and temporal spatial parameters were assessed during stance of all running trials using Visual 3D software. Peak vertical ground reaction force and step length decreased significantly from pre-cycling to immediate post-cycling measures (p=.003, p<.001), no difference existed for either variable for pre-cycling vs. 10min post-cycling. Instantaneous peak vertical loading rate (IVLR) and step rate increased significantly from pre-cycling to immediate post-cycling measures (p=.05, p<.001), no difference existed for stride rate for pre-cycling vs. 10min post-cycling. IVLR remained significantly increased at the 10 min post-cyling (p=.035). The study findings suggest that fatigue from prolonged cycling can negatively impact triathletes’ ability to attenuate ground reaction forces in subsequent running.
Listed In: Biomechanics, Gait, Sports Science

Sensitivity to Marker Placement in the TSRHC Foot Model

Multi-segmented foot and ankle (FandA) models provide more information regarding intrinsic foot motion compared to rigid-body models due to additional markers on bony landmarks of the foot. Marker placement sensitivity is a concern, especially in patients with bony abnormalities, because kinematics vary with marker placement deviations. PURPOSE: Assess kinematic changes due to marker placement error using the TSRHC multi-segmented FandA model. METHODS: Our participant was an 18yo female lacking any prior orthopedic conditions. The Plug-in-Gait model was used with the TSRHC model. An experienced clinician executed all marker placements, systematically moving each marker approximately 2.5mm within two planes. Three dynamic trials were collected for each condition, and static trials were used to calculate exact distances markers moved. Six force plates (AMTI) were utilized to confirm a consistent walking pattern. Graphs analyzed included: 1)PIG–ankle dorsiflexion, foot rotation, foot progression angle, 2)TSRHC–hindfoot, forefoot, FF-tibia. For each condition, the peaks of affected kinematic graphs were compared to assess correlations. Intra-trial error was determined by the maximum difference across walking trials. CONCLUSION: The hindfoot was most sensitive to transverse plane marker placement errors. Markers on metatarsals periodically rose vertically when moved laterally due to foot curvature causing errors in the sagittal plane as well. The forefoot also had transverse plane errors when metatarsal markers were moved. This case study illustrates the importance of proper marker placement training when utilizing a multi-segmented foot model. A thorough understanding of a utilized model is imperative, including how sensitive the model is to marker placement.
Listed In: Biomechanics, Gait, Orthopedic Research

Modeling 3D Ground Reaction Forces During Walking Using Nanocomposite Piezo-Responsive Foam Sensors

This study presents a new technique for acquiring ground reaction forces from novel, nanocomposite piezo-responsive foam (NCPF) sensors. A shoe was fitted with four NCPF sensors located at the heel, arch, ball, and toe positions. Running data was collected simultaneously from both the shoe sensors and from a force-sensing treadmill. A portion (30 randomly selected stance phases) of the treadmill data was used to develop a predictive stochastic model of GRF based on the sensor inputs. The stochastic model was then used to predict GRF for the remaining shoe sensor data, which was then benchmarked against the treadmill data. The results indicated that this model was able to predict forces in the x-axis (anterior-posterior) with 2.38% error, forces in the y-axis (medial-lateral) with 6.01% error, and forces in the z-axis (vertical) with 2.43% error. These novel sensors hold potential to dramatically improve both the ease and expense associated with GRF data, as well as allow unprecedented ability to measure GRF during real world applications outside of the laboratory.
Listed In: Biomechanical Engineering, Gait, Mechanical Engineering, Sports Science

Dance May Improve Quality of Life But Not Gait in Individuals with Parkinson’s Disease

Purpose: Research supports the use of ballroom dance to improve balance in individuals with Parkinson’s disease (PD). This study used the Mark Morris Dance for PD program as a template for dance classes to examine the effects of dance on gait, balance, and quality of life in individuals with PD. Subjects : Eleven individuals with mild to moderate PD participated in the study. Methods : A trained instructor led dance classes for subjects once a week for 12 weeks. Participants were encouraged to use the Mark Morris Dance for PD At Home DVD twice a week for 45 minutes. Classes included a 20 min. seated warm up; a 20 min. supported standing portion focused on balance and strength; and 30 min. partnered movements for swing, shag, or tango. Data collected before and after the intervention included gait parameters (Protokinetics Zeno walkway), sway area (AMTI force platform) during mCTSIB, Mini-BESTest, Falls Efficacy Scale, Apathy Scale and PDQ-39. A paired-samples t-test was performed. Results : Participants had significant decrease in apathy following the intervention (P = 0.018). A significant decrease in the percentage of the double support phase of gait indicated individuals spent less time with both feet in contact with the ground (P = 0.019). Conclusions : An instructor-led dance class based on the Dance for PD program once per week for 12 weeks improved certain aspects of quality of life, but not necessarily gait and balance. Further research with increased frequency of supervised dance classes is indicated.
Listed In: Gait, Neuroscience, Physical Therapy

Gait Mechanics Depend Upon Quadriceps Central Activation Ratio in an Anterior Knee Pain Cohort

Gait Mechanics Depend Upon Quadriceps Central Activation Ratio in an Anterior Knee Pain Cohort Son SJ*, Kim HS†, Wiseman B‡, Seeley MK*, Hopkins JT*: *Brigham Young University, Provo, UT, †West Chester University, West Chester, PA, ‡West Virginia University, Morgantown, WV. Context: Quadriceps deficits are often present in an anterior knee pain (AKP) population. However, common self-reported classification tools including Visual Analog Scale (VAS), Kujala Anterior Knee Pain (KAKP), Tampa Scale for Kinesiophobia (TSK), Tegner Activity Level (TAL) scores, and/or other subject inclusion criteria may not be sensitive enough to identify specific movement characteristics in patients with AKP. Quadriceps central activation ratio (CAR) may help to discriminate movement characteristics in patients with AKP. Objective: To examine gait mechanics between two subdivisions of AKP patients, separated by quadriceps function (CAR < 0.95 and CAR > 0.95). AKP patients were defined by VAS, KAKP, TSK, and TAL scores. Design: Cohort. Setting: Controlled laboratory. Patients or Other Participants: 30 (M=16, F=14; 22.3±3 yrs, 175±9 cm, 72.5±14 kg) AKP patients participated: 15 Quadriceps Deficit (QD: CAR = 0.91±0.04, VAS = 3.87±1.3, KAKP = 82.9±6.6, TSK = 37.9±4.7, TAL = 6.3±1.2) and 15 Quadriceps Functional (QF: CAR = 0.97±0.01, VAS = 3.93±0.7, KAKP = 79.3±7.9, TSK = 36.9±5.2, TAL = 6.8±1.4). Interventions: Subjects performed three quadriceps maximum voluntary contractions (MVC) for 3 sec on a Biodex dynamometer (100 Hz). When MVC torque plateaued 1.5-2 sec later, a superimposed burst was transmitted to two electrodes placed on their quadriceps to measure CAR. Two successful trials were averaged for data analysis. Subjects performed five gait trials at a self-selected walking speed. Gait data were collected using high-speed video (240 Hz) and a force plate (1200 Hz). A functional analysis was used to detect mean between-group differences in gait mechanics during the entire stance phase (0-17% = loading response, 18-50% = mid-stance, 51-83% = terminal stance, and 84-100% = pre-swing). This analysis allowed us to compare variables as polynomial functions rather than discrete values. If 95% confidence intervals did not overlap zero, significant differences existed between groups (p < 0.05). Main Outcome Measures: Sagittal-plane knee joint angle (˚), internal knee joint torque (N∙m), and vertical ground reaction force (VGRF; N/kg). Results: Relative to QF patients, QD patients demonstrated (i) decreased knee flexion angle at 4-90% of stance, (ii) reduced internal knee extension torque at 14-32% of stance, and (iii) reduced VGRF at 19-37% of stance and increased VGRF at 46-70% of stance (p < 0.05). Conclusions: The present data suggest that relative to QF patients, QD patients adopt quadriceps weakness gait mechanics that have been reported in individuals with knee osteoarthritis, ACL reconstruction, and effused knee joints. These alterations may create long-term compensatory gait patterns at the knee and adjacent ankle and hip joints, which may lead to mechanical and biological changes in knee articular cartilage. Future research is needed to examine a potential relationship between these gait alterations and articular cartilage health over the long-term.
Listed In: Biomechanics, Gait

&#039;Moving Forward&#039;: Gait, Cognition and Associated Risk Factors: Insights from SHARE and TILDA

The established pathway of cognitive decline identifies Mild Cognitive Impairment (MCI) as a common pre-dementia syndrome. As MCI can represent the endpoint of cognitive decline or a transient state, more predictive diagnostic tools are required. A new pre-dementia syndrome, Motoric Cognitive Risk (MCR) syndrome, has been proposed. It is defined by slow gait and cognitive complaints but absence of dementia and mobility disability. MCR aims to improve on the predictive power of MCI, this study aims to explore it’s claim. Associations have been uncovered between differing cognitive domains and specific characteristics of gait. Leveraging the gait-cognitive function relationship is a novel approach to potentially highlighting those experiencing cognitive decline. However, the diagnostic tool of MCR is a new construct and currently imperfect, its efficacy not fully validated and sensitivity for dementia prediction relatively unknown. Reliable data on prevalence and risk factors help contribute to this validation process. In this presentation prevalence data for a multi-country aging study and a nationally representative community dwelling aging study will be presented. The variables available in both datasets which will be of interest in this study include; Gait Speed, Global Cognition (Mini-Mental State Exam (MMSE) score), Presence of Cognitive Complaints, Age, Body Mass Index (BMI), Dementia diagnosis (reported or imputed) and Waist Circumference. This study will inform the following research project, which will aim to assess whether specific gait components or combinations alone are better than the MCR construct in their association to cognitive decline.
Listed In: Gait, Neuroscience