Physical Therapy

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

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

Differences In Core Stability Between Collegiate Football Players With And Without Shoulder Pain

The purpose of this study was to determine differences in core stability between collegiate football players with and without non-traumatic shoulder pain. 20 collegiate football players completed tests of trunk control and muscle capacity. Control was assessed via an unstable chair placed on a force plate. Static control was assessed by center of pressure movement during seated balance using 95% confidence ellipse area (CEA; mm2) and mean velocity (MVEL; mm/s). Dynamic control was assessed during a speed and accuracy target acquisition task. Directional control (DC; mm; COP path to target) and precision control (movement around target prior to acquisition (PC; CEA mm2)) were measured. Capacity was assessed by trunk flexor (FLEX; s) and extensor endurance (EXT; s) and double-leg lowering (DLL; °). MANOVA (Eta) and t-tests (Cohen’s d) assessed group differences (p < 0.05) Core stability was not significantly different between groups. Data presented as mean ± stdev (No Pain/Pain), p-value, effect size: Static control- CEA 183 ± 129/ 131 ± 85 and MVEL 5.7 ± 3.0/6.4 ± 2.6, p = 0.38, Eta =.33; Dynamic Control- DC 49± 9/46 ± 6, p = 0.49, d =.39 and PC 143 ± 72/93± 25, p = 0.051, d = 0.93; Capacity: FLEX 77 ± 38/99 ± 32, EXT 74 ± 22/69± 28, p = 0.22, Eta= .40 and DLLT 14 ± 10/15 ± 11, p = 0.92, d =.05. Our data do not provide evidence of diminished core stability in football players with shoulder pain.

Listed In: Biomechanics, Physical Therapy

Immediate Effects of Vibrotactile Feedback on Postural Sway in Healthy Older Adults

Previous research has shown the utility of vibrotactile feedback to improve postural sway characteristics in persons with vestibular deficits. Tactile feedback given through vibration has been used more as a modality of training but immediate effects on postural control among older adults have not been investigated. PURPOSE: To compare the immediate effects of tactile vibration on postural sway in healthy older adults in challenging stance and sensory conditions. METHODS: 10 healthy older adults (76.4 ± 6.8years), performed five standing balance conditions on a AMTI forceplate for 30s each: feet together on firm surface eyes open (C1), eyes closed (C2); feet together on foam surface eyes open (C3), eyes closed (C4), and tandem stance on firm surface eyes open (C5). Participants did 2 trials of each condition both with and without vibrotactile feedback. The feedback was given using a waist belt with sensors that were activated when participants swayed in a particular direction as detected by an Xbox Kinect camera (Sensory Kinetics system; Engineering Acoustics, Casselberry, FL). Center of pressure sway area was compared within each condition using a paired samples t-test to estimate the effect of vibration. RESULTS: See Table 1. Since only 5 subjects could complete C4 data was not included in statistical analysis. CONCLUSION: Tactile vibration did not acutely effect postural sway in challenging stance conditions in healthy older adults. Long term effects of tactile vibration on postural sway in challenging stance conditions need to be investigated.
Listed In: Physical Therapy

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

Acute Effects of Lateral Ankle Sprains on Range of Motion, Single Limb Balance, and Self-Reported Function

One in three individuals who suffer a lateral ankle sprain (LAS) subsequently develop chronic ankle instability. However, our inability to properly treat acute LAS is not surprising given our limited understanding of post-LAS consequences. 12 patients (21.6±2.9yrs; 172.9±13.1cm; 79.1±21.4kg) with an acute LAS participated. All participants were evaluated for dorsiflexion range of motion (DFROM), time-to-boundary (TTB) in single limb balance (SLB), and self-reported function (SRF) at 1-week, 2-weeks, 4-weeks, 6-weeks, and 8-weeks post injury. Both the involved and uninvolved limbs were measured during the patients first test session. DFROM was assessed using the weight-bearing lunge test and all participants performed 3, 10s of single limb stance with eyes open on a force plate to measure their single limb balance. SRF was measured using the Foot and Ankle Ability Measure (FAAM) and FAAM-Sport (FAAM-S). Post injury time points were compared to a control condition using multivariate ANOVAs (α=0.05). Relative to the control condition, FAAM and FAAM-S were significantly lower at 1-week and 2-weeks post injury. The FAAM-S was also significantly lower score compare to control condition at 4-weeks post-injury. Both FAAM and FAAM-S were not significant different at 6-weeks post-injury. Post-injury TTB measures and DFROM were not significantly different from the control condition. Non-significant declines in DFROM and TTB were observed as in this sample of acute LAS and appear to present with unique recovery patterns. Different recovery patterns among the tested outcomes indicate the need for further research with a larger cohort and for a longer post-injury duration.

Listed In: Biomechanics, Physical Therapy, Posturography, Sports Science

A preliminary study on quality of knee strength measurements by means of Hand Held Dynamometer and Optoelectronic System

Strength measurements are popular in the clinical practice to evaluate the health status of patients and quantify the outcome of training programs. Currently a common method to measure strength is based on Hand Held Dynamometers (HHD) which is operator-dependent. Some studies were conducted on repeatability of strength measurements but they were limited to the statistical analysis of repeated measurements of force. In this work, the authors developed a methodology to study the quality of knee flexion/extension strength measurements by measuring the effective HHD position and orientation with respect to the patient. HHD positioning attitude was measured by means of an Optoelectronic System for which a marker protocol was defined ad-hoc. The approach allowed to assess quality of measurements and operator’s ability by means of quantitative indices. The protocol permitted the evaluation of: angles of HHD application, angular range of motion of the knee and range of motion of the HHD. RMSE parameters allowed to quantify the inaccuracy associated to the selected indices. Results showed that the operator was not able to keep the subject’s limb completely still. The force exerted by the subject was higher in knee extension and the knee range of motion was higher than expected, however the operator had more difficulties in holding the HHD in knee flexion trials. This work showed that HHD positioning should be as accurate as possible, as it plays an important role for the strength evaluation. Moreover, the operator should be properly trained and should be strong enough to counteract the force of the subject.
Listed In: Biomechanical Engineering, Biomechanics, Physical Therapy, Sports Science

Sensory contributions to standing balance in unilateral vestibulopathy

Patients with unilateral peripheral vestibular disorder (UPVD) have diminished postural stability and therefore the aim of this study was to examine the contribution of multiple sensory systems to postural control in UPVD. Seventeen adults with UPVD and 17 healthy controls participated in this study. Centre of pressure (COP) trajectories were assessed using a force plate during six standing tasks: Forwards and backwards leaning, and standing with and without Achilles tendon vibration, each with eyes open and eyes closed. Postural stability was evaluated over 30s by means of: total COP excursion distance (COPPath) and the distances between the most anterior and posterior points of the COPPath and the anterior and posterior anatomical boundaries of the base of support (COPAmin and COPPmin). In addition, the corrected COPAmin and COPPmin was assessed by taking the corrected base of support boundaries into account using the anterior and posterior COP data from the leaning tasks. UPVD patients showed a tendency for smaller limits of stability during the leaning tasks in both directions. Subject group and task condition effects were found (P<0.05) for COPPath, (i.e. higher values for patients compared to controls). UPVD patients showed lower (P<0.05) COPPmin values compared to the control group for all conditions (more pronounced with the corrected COPPmin). Disturbance of the visual system alone lead to a distinct postural backward sway in both subject groups which became significantly more pronounced in combination with Achilles tendon vibration. The individual limits of stability should be considered in future research when conducting posturographic measurements.
Listed In: Biomechanics, Neuroscience, Physical Therapy, Posturography

Perception of Self-Motion Impacts the Variability of Plantar Propulsion Force in Diabetes

People with diabetes mellitus (DM) have been reported of increased ground reaction force (GRF) and plantar propulsion force (PPF) that will worsen the formation of plantar ulcer. The reliance of perception of self-motion has been previously addressed for maintaining stability during locomotion in DM. Therefore, we speculate that perception of self-motion will affect DM’s plantar force adjustment by decreasing GRF/PPF along with reducing of variability (CV). We recruited five DMs and three healthy controls to walk on an instrumented treadmill with their self-selected pace. All subjects went through three no self-motion and three self-motion walking trials (120s/trial). The self-motion was generated by presenting a virtual corridor that moved toward subjects with their matched velocity. Three-axis force data were recorded at 300 Hz. Two-factor ANOVA with repeated measures were conducted to examine the role of visual cue impacts GRF/PPF in DM and age-matched healthy. The visual cue and group factors show significant interaction on PPFPeak and PPFCV. The following comparisons showed significant visual effect on reducing: (1) PPFPeak in healthy controls; (2) PPFCV in DM patients. Generally, the decreased PPFPeak and PPFCV founded in this study were in line with previous study and can be explained as the optimization of neuromuscular locomotor system in the anteroposterior direction. Furthermore, visual perception of self-motion shows its effect on reducing PPFPeak during toe-off in healthy controls. Lastly, the significant decreased PPFCV of DM versus healthy stands for the reduced human movement variability observed in DM’s neuromuscular locomotor system when perception of self-motion is provided.
Listed In: Biomechanics, Gait, Physical Therapy

Static postural control does not strongly predict dynamic gait stability recovery following a trip in adults with and without vestibular dysfunction

Unilateral peripheral vestibular disorder (UPVD) negatively affects upper and lower body motor performance, but postural control during quiet stance in UPVD patients has not been directly compared with dynamic stability control after an unexpected perturbation during locomotion. We analysed centre of pressure (COP) characteristics during static posturography in UPVD patients and healthy controls and compared this with performance of a trip recovery task. 17 UPVD patients and 17 healthy controls were unexpectedly tripped while walking on a treadmill. The margin of stability (MoS) was calculated at touchdown (TD) of the perturbed step and the first six recovery steps. Posturography was used to assess postural stability during 30 seconds of standing with eyes open and closed using a force plate. The trip reduced the MoS of the perturbed leg (p<0.05) with no significant differences in MoS between the groups. Controls returned to MoS baseline level in five steps and patients did not return within the six steps. UPVD patients showed a greater total COP sway path excursion (closed eyes only), anterior-posterior range of COP distance and a more posterior COP position in relation to the posterior boundary of the base of support. There were no significant correlations between COP sway path excursion and MoS values. We concluded that UPVD patients have a diminished ability to control and recover dynamic gait stability after an unexpected trip and lower static postural stability control compared to healthy matched controls, but that trip recovery and static postural control rely on different control mechanisms.
Listed In: Biomechanics, Gait, Neuroscience, Physical Therapy, Posturography