Limb Loading Research Articles

The Analysis of Pedaling Techniques with Platform Pedals

The paper analyzes a pedaling technique with platform pedals in which the influence of the geometric and tribological parameters on the torque course of the active forces in the crank rotation axis is determined. Distribution of forces of feet acting on pedals as a function of the crank rotation angle was performed and on this basis the specific pedaling zones and their ranges and the courses of the value of variable active torque and pedaling work during the full cycle were determined. The course of changes in the movements in the ankle joint is described with a function depending on the crank and limb position and loading of the joint. A numerical example has also been presented and a discussion of the results has been carried out

The effect of leg length discrepancy upon load distribution in the static phase (standing)

Leg length discrepancy (LLD) is commonly recognised as a complication of total hip arthroplasty. Some patients with only minor LLD complain of major difficulties. The effect of LLD has been described in the dynamic phase, but not static phase. The aim of this project was to investigate the effect of leg length discrepancy on static limb loading (i.e. Standing). A pedobarograph was used to measure the limb loading of 20 normal volunteers whilst changing the height of the other foot thus simulating a LLD. With both feet at the same level, the left limb took 54% of the load. When the right foot was lower, (simulating a long left leg), the left leg took 39% of the load. When the right foot was higher, (simulating a long right leg), the left leg took 65% of the load. A paired t-test comparison of the simulation with the level load showed a significant difference with P=0.002. Our results show that weight distribution increased in the shorter limb when LLD was simulated. This uneven distribution is likely to lead to premature fatigue when standing and may explain why some patients with LLD post hip arthroplasty have poorer outcomes.

Perception of lower extremity loads in stroke survivors

ObjectiveThis study aimed to improve our understanding of static and dynamic lower extremity sensory perception and the impact of sensory impairments on the control of walking in stroke survivors. MethodsUsing a custom, real-time unloading system, we tested load perception at heel strike, mid stance and push off in 10 stroke survivors and compared their performance to 10 age-matched and 5 young adult control subjects. Dynamic load perception was based on a judgment of which leg was bearing more load, which was altered on a step by step basis. We also examined lower extremity static load perception, coordination, proprioception, balance, and gait symmetry. ResultsThe stroke survivors performed significantly worse than the control subjects in dynamic load perception, coordination, proprioception, balance and gait symmetry. Gait symmetry correlated with static and dynamic load perception measures but not with age, proprioception, coordination, and balance. ConclusionsSensory deficits related to load detection in the impaired limb could result in an increased uncertainty of limb load and a gait strategy in which stroke survivors minimize loading of the impaired limb. SignificanceThis new method of measuring lower extremity dynamic load perception provides a framework for understanding gait-related sensory impairments in stroke survivors.

Can Measures of Limb Loading and Dynamic Stability During the Squat Maneuver Provide an Index of Early Functional Recovery After Unilateral Total Hip Arthroplasty?

ObjectiveTo investigate limb loading and dynamic stability during squatting in the early functional recovery of patients who had undergone total hip arthroplasty (THA). DesignCohort study. SettingInpatient rehabilitation clinic. ParticipantsOf the total participants (N=99), a random sample of patients who had undergone THA (n=61; 34 men and 27 women; mean age, 62±9y; weight, 77±14kg; height, 174±9 cm) was assessed twice, 13.2±3.8 days (t1) and 26.6±3.3 days postsurgery (t2), and compared with a healthy reference group (n=38; 22 men and 16 women; mean age, 47±12y; weight, 78±20kg; height, 175±10cm). InterventionsPatients who had undergone THA received 2 weeks of standard inpatient rehabilitation. Main Outcome MeasuresInterlimb vertical force distribution and dynamic stability during the squat maneuver, as defined by the root mean square of the center of pressure in anteroposterior and mediolateral directions, of operated and nonoperated limbs. Self-reported function was assessed via the Function Assessment Questionnaire Hannover for Osteoarthritis questionnaire. ResultsAt t1, unloading of the operated limb was 15.8% greater (P<.001; d=1.070) and anteroposterior and mediolateral center of pressure root mean square values were 30% to 34% higher in patients who had undergone THA than in the healthy reference group (P<.05). Unloading was reduced by 12.8% toward a more equal distribution from t1 to t2 (P<.001; d=.874). Although mediolateral stability improved between t1 and t2 (operated limb: 14.8%; P=.024; d=.397; nonoperated limb: 13.1%; P=.015; d=.321), anteroposterior stability was not significantly different. Self-reported physical function improved by 15.8% (P<.001; d=.965). ConclusionsPatients who had undergone THA unload the operated limb and are dynamically more unstable during squatting in the early rehabilitation phase after THA than are healthy adults. Although loading symmetry and mediolateral stability improved to the level of healthy adults with rehabilitation, anteroposterior stability remained impaired. Measures of dynamic stability and load symmetry during squatting provide quantitative information that can be used to clinically monitor early functional recovery from THA.

Potential regenerative rehabilitation technology: implications of mechanical stimuli to tissue health.

BackgroundMechanical loads induced through muscle contraction, vibration, or compressive forces are thought to modulate tissue plasticity. With the emergence of regenerative medicine, there is a need to understand the optimal mechanical environment (vibration, load, or muscle force) that promotes cellular health. To our knowledge no mechanical system has been proposed to deliver these isolated mechanical stimuli in human tissue. We present the design, performance, and utilization of a new technology that may be used to study localized mechanical stimuli on human tissues. A servo-controlled vibration and limb loading system were developed and integrated into a single instrument to deliver vibration, compression, or muscle contractile loads to a single limb (tibia) in humans. The accuracy, repeatability, transmissibility, and safety of the mechanical delivery system were evaluated on eight individuals with spinal cord injury (SCI).FindingsThe limb loading system was linear, repeatable, and accurate to less than 5, 1, and 1 percent of full scale, respectively, and transmissibility was excellent. The between session tests on individuals with spinal cord injury (SCI) showed high intra-class correlations (>0.9).ConclusionsAll tests supported that therapeutic loads can be delivered to a lower limb (tibia) in a safe, accurate, and measureable manner. Future collaborations between engineers and cellular physiologists will be important as research programs strive to determine the optimal mechanical environment for developing cells and tissues in humans.

The Effect of Perineural Anesthesia and Handler Position on Limb Loading and Hoof Balance of the Vertical Ground Reaction Force in Sound Horses

IntroductionTo facilitate interpretation of limb loading and hoof balance obtained by pressure plate analysis in lame horses, the effects of handler position and perineural anesthesia in sound horses need investigation.MethodsSix sound Warmblood horses were walked and trotted over a pressure plate, with the handler at the left and subsequently the right side, and before and after a bilateral palmar digital nerve block. One week later, this procedure was repeated before and after a bilateral abaxial sesamoid nerve block. Peak vertical force (PVF), vertical impulse (VI) and stance time (ST) of 5 hoof prints of both forelimbs were obtained (126 Hz). Asymmetry ratios were calculated.Toe‐heel and medio‐lateral hoof balance curves of the vertical force were calculated. Mixed model ANOVA was used for statistical analysis of asymmetry ratios (α = 0.05). Hoof balance curves were assessed qualitatively.ResultsThere were no significant effects of handler position and perineural anesthesia on PVF and VI; small but significant effects of perineural anesthesia on ST at walk were associated with variability in horses′ speed between sessions at walk (P = 0.046); no significant differences at trot. Hoof balance curves were not affected by handler position or perineural anesthesia, and were highly repeatable within each individual horse.ConclusionsThe lack of any effect of handler position or perineural anaesthesia on limb loading and toe‐heel and medial‐lateral hoof balance in sound horses makes it probable that significant aberrations found using pressure plate analysis are related to abnormalities and hence may be relevant in lameness diagnosis.Ethical Animal ResearchThe study was approved by the ethical committee of the Faculty of Veterinary Medicine of Ghent University (n° 2012/151). Sources of funding: Ghent University. Competing interests: none.

Distal Forelimb Kinematics During the Extended Trot of Dressage Horses Ridden on Two Different Arena Surfaces

IntroductionSuspensory apparatus injuries are common in dressage horses. Studies demonstrate that surface type affects hoof forces and distal limb kinematics of equine athletes. Because synthetic race surfaces have lower stiffness and limb loads than dirt surfaces, it was hypothesized that dressage horses have less fetlock hyperextension on a synthetic surface than a dirt surface.MethodsTwo‐dimensional, high‐speed videos (250 Hz, 2 ppcm) of 6 dressage horses (ages 8–13; 5 males, 1 female) during extended trot on dirt and synthetic surfaces (6 trials (strides) per horse per surface) were digitized (low‐pass Butterworth filter, 15 Hz). Fetlock and solar hoof angles determined from skin and hoof markers were compared between surfaces using a mixed model ANCOVA that accounted for horse velocity (saddle billet marker) and repeated horse measures. Surface mechanical behaviors were characterized using a track testing device. Maximum force, time to maximum force, maximum displacement, resting rebound, maximum vertical rebound, average stiffness, and maximum load rate were compared between surfaces and time of day (morning, afternoon) using a general linear model ANOVA.ResultsMaximum and toe off fetlock angles were greater on the synthetic surface compared to dirt (Δ = 2°, P = 0.070). Mean maximum fetlock angle on the synthetic surface was 260°. The maximum load rate of the synthetic surface was 5 times greater than the dirt surface (P = 0.0086).ConclusionsSynthetic surfaces were designed to reduce injuries in equine athletes. Because suspensory apparatus elongation is largely dependent on fetlock extension, it is possible that suspensory apparatus strain is greater on synthetic surfaces. Thus, surface design may require more refinement to promote injury prevention based on horse discipline and gait.Ethical Animal ResearchThe University of California, Davis Institutional Animal Care and Use Committee reviewed and approved the protocols used in the study. Owner informed consent was obtained for all study horses. Sources of funding: Merial (A Sanofi Company) in association with the Student Training in Advanced Research (STAR) program, School of Veterinary Medicine, University of California, Davis and the Endowed Research Funds of School of Veterinary Medicine, University of California, Davis. Competing interests: none.

Effect of Speed on Stride Parameters and Limb Loading: Comparison between Forelimb and Hindlimb at Training Trot on a Firm Surface

IntroductionDirect measurement of peak vertical force in equine forelimbs and hindlimbs under training conditions has not been achieved to date. This measurement is possible using dynamometric horseshoes (DHSs). The objectives of this study were to investigate, on a firm surface, the effect of speed on stride parameters and on vertical loading in the forelimb (FL) compared to the hindlimb (HL).MethodsRight front and hind hooves of 5 trotters were equipped with a DHS. A linear corridor was delimited on a firm sand training track. Each horse alternately repeated trials (harness trot) at 25, 35 and 40 km/h (4 to 6 times at each speed). For each trial, stride parameters and dynamic variables (peak vertical force and impulse, vertical loading rate) were analysed for 10 successive strides. Correlation coefficients were calculated to quantify the association between speed and the studied variables; linear mixed‐effects regression models were used to test the significance (P&lt;0.05) of these associations.ResultsStance and stride duration, and their ratio (duty factor) were linearly correlated with speed (r&lt;‐0.82), both in FL and HL. Peak vertical force was the only variable for which r was higher in HL (r = 0.80 vs. 0.50 in FL). The relationship between vertical loading rate and speed had the highest r of all dynamic variables (r = 0.87 and 0.83, respectively in FL and HL; r = ‐0.75 and −0.60 for vertical impulse).ConclusionsThe linear relation between peak vertical force and speed demonstrated in the hindlimb differs from previous studies at lower speed. These results stress the necessity of performing biomechanical measurements under real training conditions.Ethical Animal ResearchFormal approval provided by the local Animal Care and Ethics Committee. Sources of funding: the Région Basse‐Normandie, the FEDER, the Fonds Eperon and the IFCE. Competing interests: none.

Jumping Technique Alters Limb Kinematics in Showjumping Horses

IntroductionShowjumping (SJ) horses are at increased risk of distal forelimb soft tissue injuries; generally attributed to limb loading on landing. This study investigated relationships between the back, trailing limb angles at take‐off, in flight and at landing.MethodsEight showjumpers jumped a 140 cm vertical obstacle (part of a 15‐fence course). Two‐dimensional high‐speed motion‐capture (250 Hz) was used to measure limb and regional back kinematics in the dorsoventral plane from markers placed at predetermined locations. Pearson's correlation tests were used to determine associations between limb and back angles at take‐off, in flight and upon landing.ResultsAll markers were clearly visible throughout. Greater head‐neck ventroflexion at take‐off was associated with decreased hock flexion (r = ‐0.81, P = 0.0141), and decreased neck‐trunk angle on landing (r = 0.77, P = 0.03). Greater head‐neck ventroflexion at landing, 50% and 75% flight was associated with decreased carpal extension on landing (r = 0.81, 0.84, 0.73; P = 0.02, 0.01, 0.04 respectively). Increased thoracolumbar and lumbosacral flexion at take‐off was associated with decreased metatarsophalangeal joint extension upon landing (r = 0.78, 0.75; P = 0.03). Greater lumbosacral flexion at 50 and 75% flight (r = ‐0.73, −0.77; P = 0.04, 0.03 respectively) and greater thoracolumbar flexion at 25, 50 and 75% flight was associated with decreased elbow flexion on landing (r = ‐0.87, −0.78, −0.76; P = 0.01, 0.02, 0.03 respectively).ConclusionsDecreasing head‐neck angle and increasing thoracolumbar and lumbosacral flexion at take‐off and in flight appeared to alter peak joint flexion and extension on landing. This suggests that optimising jumping technique in training may be beneficial to reduce the strain placed on the limbs at landing, which could potentially be valuable given the risk of distal limb soft tissue injuries in SJ horses.Ethical Animal ResearchThe Royal College of Veterinary Surgeons confirmed that the procedures carried out were not Controlled Procedures under UK animal experimentation legislation. Explicit owner informed consent for participation in this study is not stated. Sources of funding: The World Class Development Programme is funded by the Department for Culture, Media and Sport, through Exchequer and National Lottery funds, via UK Sport. Competing interests: none.

The Point of Application of the Ground Reaction Force Moves in Circling Horses

IntroductionThe position and magnitude of the ground reaction force (GRF) relative to the hoof influences loading within the limbs. In this study, we investigated changes to the point of force application (PFA) of the GRF in horses walking and trotting on circles compared to a straight line.Methods8 horses were lunged in 6 m diameter circles (left and right), and led straight, at walk and trot over force plates on firm ground. Hoof‐mounted retro‐reflective markers were tracked using a motion capture system (Motion Analysis Corp). The PFA was computed in a hoof‐local coordinate system during 2018 strides. The instantaneous PFA was weighted by the GRF magnitude to compute an average PFA position within the hoof print for each total stance phase. The average PFAs were analyzed using an ANOVA in which type of locomotion (circle or straight), gait (walk or trot) and hoof (fore or hind) were used as independent variables. A Tukey post‐hoc analysis identified pair‐wise differences.ResultsAt trot, the PFA moved toward the center of the circle by 19.8 ± 10 mm (mean ± SD, P&lt;0.001). At walk there was no significant difference in PFA between straight and circle. The hoof (fore or hind) did not significantly affect the PFA shift.ConclusionsThe significant medio‐lateral shift of PFA suggests that the balance of limb loading changes during circular locomotion. This is likely to affect the medio‐lateral balance in the distal joints and cause sub‐optimal loading of limb structures.Ethical Animal ResearchThe study was approved by the MSU Institutional Animal Care and Use Committee, protocol #06/11‐112‐00. Sources of funding: This study was funded by the McPhail Endowment. SD Starke's collaborative research visit for this project was funded by the British Society for Animal Science, Murray Black Award. Competing interests: none.

Does Intact Limb Loading Differ in Servicemembers With Traumatic Lower Limb Loss?

The initiation and progression of knee and hip arthritis have been related to limb loading during ambulation. Although altered gait mechanics with unilateral lower limb loss often result in larger and more prolonged forces through the intact limb, how these forces differ with traumatic limb loss and duration of ambulation have not been well described. The purpose of this study was to determine whether biomechanical variables of joint and limb loading (external adduction moments, vertical ground reaction force loading rates, and impulses) are larger in the intact limb of servicemembers with versus without unilateral lower limb loss and whether intact limb loading differs between shorter (≤ 6 months) versus longer (≥ 2 years) durations of ambulation with a prosthesis. A retrospective review was conducted of all clinical and research gait evaluations performed in the biomechanics laboratory at Walter Reed Army Medical Center and Walter Reed National Military Medical Center between January 2008 and December 2012. Biomechanical data meeting all inclusion and exclusion criteria were obtained for 32 individuals with unilateral transtibial limb loss, 49 with unilateral transfemoral limb loss, and 28 without limb loss. Individuals with unilateral lower limb loss were separated by their experience ambulating with a prosthesis at the time of the gait collection, ≤ 6 months or ≥ 2 years, to determine the effect of duration of ambulation with a prosthesis. Intact limb mean and peak vertical ground reaction force loading rates (median [range; 95% confidence interval]) were larger for transtibial subjects with ≤ 6 months of experience ambulating with a prosthesis versus control subjects (mean: 12.13 body weight [BW]/s [4.45-16.79; 10.18-12.81] versus 9.03 BW/s [4.64-14.47; 8.26-9.74]; effect size [ES] = 0.40; p = 0.003; and peak: 17.23 BW/s [6.58-25.25; 15.46-19.01] versus 13.60 BW/s [9.82-19.51; 12.98-15.05]; ES = 0.43; p = 0.001), respectively. Intact limb mean and peak vertical ground reaction force loading rates were also larger in subjects with transfemoral limb loss with ≤ 6 months and ≥ 2 years of experience ambulating with a prosthesis versus control subjects (mean: 12.67 BW/s [5.88-18.15; 11.06-14.47] and 12.59 BW/s [8.08-17.39; 11.83-13.68] versus 9.03 BW/s [4.64-14.47; 8.26-9.74]; ES ≥ 0.53; p < 0.001; peak: 19.82 BW/s [11.93-29.43; 18.35-23.05] and 21.33 BW/s [16.68-36.69; 20.66-24.26] versus 13.60 BW/s [9.82-19.51; 12.98-15.05]; ES ≥ 0.68; p < 0.001, respectively). Similarly, intact limb vertical ground reaction force impulses (0.63 BW·s [0.53-0.81; 0.67-0.69] and 0.62 BW·s [0.55-0.74; 0.60-0.63] versus 0.57 BW·s [0.50-0.66; 0.55-0.58]; ES ≥ 0.53, p < 0.001) were also larger among both groups of transfemoral subjects versus control subjects, respectively. Limb loading variables were not statistically different between times ambulating with a prosthesis within groups with transtibial or transfemoral limb loss. Larger intact limb loading in individuals with traumatic transtibial loss were only noted early in the rehabilitation process, but these variables were present early and late in the rehabilitation process for those with transfemoral limb loss. Such evidence suggests an increased risk for early onset and progression of arthritis in the intact limb, especially in those with transfemoral limb loss. Interventions should focus on correcting modifiable gait mechanics associated with arthritis, particularly among individuals with transfemoral limb loss, to potentially mitigate the development and progression in this population.

Upper limb loading in elbow flexor spastic dystonia

Upper limb loading in elbow flexor spastic dystonia

Clinically-relevant measures associated with altered contact forces in patients with anterior cruciate ligament deficiency

BackgroundKnee joint contact forces are altered after anterior cruciate ligament injury during walking and may be related to clinically-relevant measures of impairments or self-reported function. The purpose of this study was to investigate the association of several clinically-relevant measures with altered knee contact forces in patients with anterior cruciate ligament injury. MethodsData for this study represent a cross-sectional observational analysis of thirty-seven (23 M, 14 F) patients with complete unilateral anterior cruciate ligament injury. Gait analysis with electromyography was used to obtain estimates of tibiofemoral joint contact force using an electromyography-driven musculoskeletal model. Multivariable linear regression was used to identify measures associated with tibiofemoral joint contact force. FindingsInvolved knee extensor muscle strength and patient-reported knee function on the Global Rating Scale of perceived function were significantly associated with peak tibiofemoral contact force for the involved limb. Patients who were stronger and who perceived higher knee function walked with greater contact forces on their involved knees. After controlling for walking speed, involved extensor strength explained 8.9% of the variance in involved peak tibiofemoral contact force and score on the Global Rating Scale explained an additional 9.4% of the variance. InterpretationImprovements in involved quadriceps strength and overall function as measured by patient self-report may be important for increasing involved limb contact forces, thereby restoring loading symmetry in these patients who demonstrate decreased involved limb loading after injury. These results highlight the potential value of studying the recovery of strength, self-reported function and joint loading symmetry in patients with anterior cruciate ligament injury.

Coupling Dynamics Interlip Coordination in Lower Lip Load Compensation

PURPOSE To study the effects of lower lip loading on lower and upper lip movements and their coordination to test predictions on coupling dynamics derived from studies in limb control. METHOD Movement data were acquired using electromagnetic midsagittal articulography under 4 conditions: (a) without restrictions, serving as a baseline; (b) with a small carrier device attached to the lower lip; (c) with a 50-g weight added to the device; and, at the end of the session (d) with the weight and device removed. For all conditions, 8 participants repeated nonwords at 2 speaking rates. Movement data were used to derive discrete kinematic measures, a cyclic index of spatiotemporal variability, phase deviations, and standard deviations of relative phase for interlip coupling. RESULTS Kinematic variables were not systematically affected by lower lip load. Phase deviations also showed no change, but in contrast, phase variability showed a significant increase for the lower lip load condition at fast rates. CONCLUSION Lower lip load effects are comparable to the reported impact of homologous limb loading, showing evidence for a tight coupling between both lips in line with predictions from coordination dynamics accounts in the literature.

The impact of foot position on sit-to-stand stability and lower limb loading in hemiplegic stroke patients

Objective To explore the effects of different foot positions on lower limb loading and the sit- to-stand stability of hemiplegic stroke patients. Methods Thirty-six hemiplegic stroke patients were recruited as the experimental group and 36 healthy elderly as the control group. Both groups of subjects completed sit-to-stand movements with 3 different foot positions： （ 1 ） both feet （BF） placed at 10° of ankle dorsiflexion; （2） the paretic foot placed posterior （PFP） for hemiparetic subjects or the undominant foot placed posterior （UDFP） for healthy subjects; （3） the non-paretic foot placed posterior （NPFP） for hemiparetic subjects or the dominant foot placed posterior （DFP） for healthy subjects. The time required to rise from sitting, the average load difference （ALD） be- tween the left and right feet and sway of the center of gravity in the mediolateral direction （COGX） were measured. Results Comparing BF with PFP positioning, the time to rise was not significantly different but the loads on the two legs, the ALD and the COGX in were all significantly different. Comparing NPFP with PFP positioning, all the indexes were significantly different, and the time to rise was significantly different from the BF positioning. For the control group, all the indexes significantly different in the BP and PFP positions, and the time to rise was signifi- cantly different from that required with the UDFP placement. In all 3 foot positions, all of the experimental group＇ s indices differed significantly from those of the control group. In both groups there was a strong positive correlation between the average ALD and COGX values in all three foot positions. Conclusions Foot placement influences lower limb loading and stability in rising from sitting for hemiplegic stroke survivors. The greater the symmetry of lower limb loading, the better the postural stability. Key words: Stroke ; Hemiplegia; Sit-to-stand ; Posture ; Lower limb loading

Influence of a specialized training program on the changes in the level of balance abilities in 8-10 year old alpine skiers

Background: Alpine skiing is a sport with a very complex structure and a high variability of movements. The stage of preliminary sport preparation in alpine skiing is important in a relation to the need of creating physical demands which enable an optimal and continuous growth of the performance. Inline skating is a very good substitution with a similar loading of lower limbs and muscle involvement as in skiing because inline skates offer a sense of sliding; stance and edge change and the technique for making curves are very similar. Objective: The main purpose of this paper was to assess the influence of a 9 week specialized training program on the changes in the level of balance abilities development of 8-10 year old children in alpine skiing. This specialized training program consisted of exercises on inline skates and from balance exercises on non-specific equipment. Methods: This research was organized by using a single-factor parallel experiment with two groups. Specialized motion program was 9 weeks long and it was used in the experimental group during the preparatory period in the stage of preliminary sport preparation. The experimental group completed a total of 90&#8239;minutes of specialized training per week, of which 60&#8239;minutes were special exercises on inline skates and 30&#8239;minutes were exercises for development of balance skills on non-specific tools. The control group underwent generally focused training. To determinate the level of balance we used tests of both static and dynamic balance. Results: Based on the tests results we found statistically significant improvement of the performance in all of the tests for balance abilities in the experimental group due to the specialized training program. The control group showed no significant differences during generally focused training process on the development of physical abilities. Conclusions: A 9 week training program consisting of 3 training sessions per week was long enough to have a positive influence on the development of balance abilities of children of school age in alpine skiing. We included specific ski-motions into the nonspecific movements using methods for the development of balance abilities in the duration of 30&#8239;minutes at the beginning of each training session.

Load-induced changes in older individual's hand-finger tremor are ameliorated with targeting

The purpose of this study was to investigate hand–finger tremor dynamics when a load was applied to the finger in a group of healthy older adults. Moreover, we sought to determine if projecting a representation of the subject's finger tremor on a target was capable of overcoming the effects of loading so that hand–finger interactions returned to a state that was similar to normal tremor. Eight healthy older males (67±1year) performed a postural pointing task, where tremor was assessed using lightweight accelerometers attached to the hand and finger. Tremor was then assessed when a laser pointer was attached to the finger and switched off (the load), and then with the laser pointer attached and switched on pointing at targets of 40mm and 20mm in diameter. The main findings of this study were that 1) loading the finger resulted in a reduction in finger tremor amplitude and increased finger tremor regularity, but no change in hand tremor, 2) loading caused increased hand–finger 8–12Hz cross wavelet coherence and phase synchrony, and 3) pointing at different targets while the finger was loaded resulted in an increase in finger tremor amplitude, and changes in inter-segmental coupling to the extent that hand–finger dynamics reflected normal unloaded conditions. Overall, these results illustrate that the damping effects of limb loading can be offset, in part, by altering the accuracy demands of the task to make the pointing action more challenging.

A preliminary study on pressure‐plate evaluation of forelimb toe–heel and mediolateral hoof balance on a hard vs. a soft surface in sound ponies at the walk and trot

Thus far, pressure-plate analysis has been limited to measurements on a hard surface, whereas equine athletes routinely perform on a deformable substrate. To explore pressure-plate analysis on arena footing. Nonrandomised crossover study using noninvasive techniques. Five sound, unshod ponies were walked and trotted over a pressure plate in 2 different conditions. In the first session, the plate was covered with only a 5 mm rubber mat, and in the second session, with an additional 50 mm layer of sand and synthetic fibres. Limb loading and timing variables (peak vertical force, vertical impulse, peak vertical pressure, hoof contact area and stance phase duration) were obtained. Toe-heel and mediolateral hoof balance of the vertical force were calculated throughout stance (126 Hz). Peak vertical force, vertical impulse, peak vertical pressure and stance phase duration were decreased on the soft substrate, while hoof contact area increased. At impact, there was more even load distribution between the toe and heel region on the soft vs. hard surface. At mid-stance, there was more loading of the toe region on the soft compared with the hard surface. At impact, there was more even load distribution between lateral and medial on the soft vs. hard surface at walk, but not at trot. Comparison of observed vs. expected impulse indicated that the main factor involved in the lower loading on the soft surface is the dampening effect of the soft substrate, although definitive conclusions require concurrent force-plate analysis. The pressure plate permitted quantitative evaluation of hoof balance of the vertical force on a deformable surface at the walk and trot and proved that there is more even load distribution on arena footing.

Accuracy of a digital weight scale relative to the nintendo wii in measuring limb load asymmetry.

[Purpose] The aim of the present study was to investigate the accuracy of a digital weight scale relative to the Wii in limb loading measurement during static standing. [Methods] This was a cross-sectional study conducted at a public university teaching hospital. The sample consisted of 24 participants (12 with osteoarthritis and 12 healthy) recruited through convenient sampling. Limb loading measurements were obtained using a digital weight scale and the Nintendo Wii in static standing with three trials under an eyes-open condition. The limb load asymmetry was computed as the symmetry index. [Results] The accuracy of measurement with the digital weight scale relative to the Nintendo Wii was analyzed using the receiver operating characteristic (ROC) curve and Kolmogorov-Smirnov test (K-S test). The area under the ROC curve was found to be 0.67. Logistic regression confirmed the validity of digital weight scale relative to the Nintendo Wii. The D statistics value from the K-S test was found to be 0.16, which confirmed that there was no significant difference in measurement between the equipment. [Conclusion] The digital weight scale is an accurate tool for measuring limb load asymmetry. The low price, easy availability, and maneuverability make it a good potential tool in clinical settings for measuring limb load asymmetry.

CSM 2014 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1–SPL66)

CSM 2014 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1–SPL66)