Comparison between the Original- and a Standardized Version of a Physical Assessment Test for the Dorsal Chain - A Cohort-Based Cross Sectional Study.

This cohort-based cross-sectional study compares the original (OV) and a newly developed standardized version (SV) of the Bunkie Test, a physical test used to assess the dorsal chain muscles. Twenty-three participants (13 females, 10 males; median age of 26 ± 3 years) performed the test, a reverse plank, with one foot on a stool and the contralateral leg lifted. In the SV, the position of the pelvis and the foot were predefined. The test performance time (s) and surface electromyography (sEMG) signals of the dorsal chain muscles were recorded. We performed a median power frequency (MPF) analysis, using short-time Fourier transformation, and calculated the MPF/time linear regression slope. We compared the slopes of the linear regression analysis (between legs) and the performance times (between the OV and SV) with the Wilcoxon test. Performance times did not differ between SV and OV for either the dominant (p = 0.28) or non-dominant leg (p = 0.08). Linear regression analysis revealed a negative slope for the muscles of the tested leg and contralateral erector spinae, with a significant difference between the biceps femoris of the tested (-0.91 ± 1.08) and contralateral leg (0.01 ± 1.62) in the SV (p = 0.004). The sEMG showed a clearer pattern in the SV than in the OV. Hence, we recommend using the SV to assess the structures of the dorsal chain of the tested leg and contralateral back.

Myofascial Treatment Techniques on the Plantar Surface Influence Functional Performance in the Dorsal Kinetic Chain.

Prior studies have shown that self- and manual massage (SMM) increases flexibility in non-adjacent body areas. It is unclear whether this also influences performance in terms of force generation. Therefore, this study investigated the effect of SMM on the plantar surface on performance in the dorsal kinetic chain. Seventeen young participants took part in this within-subject non-randomized controlled study. SMM was applied on the plantar surface of the dominant leg, but not on the non-dominant leg. A functional performance test of the dorsal kinetic chain, the Bunkie Test, was conducted before and after the intervention. We measured the performance in seconds for the so-called posterior power line (PPL) and the posterior stabilizing line (PSL). The performance of the dominant leg in the Bunkie Test decreased significantly by 17.2% from (mean ± SD) 33.1 ± 9.9 s to 27.4 ± 11.1 s for the PPL and by 16.3% from 27.6 ± 9.8 s to 23.1 ± 11.7 s for the PSL. This is in contrast to the non-dominant leg where performance increased significantly by 5.1% from 29.7 ± 9.6 s to 31.1 ± 8.9 s for the PPL and by 3.1% from 25.7 ± 1.5 s to 26.5 ± 1.7 s for the PSL. SMM interventions on the plantar surface might influence the performance in the dorsal kinetic chain.

Effects of sensorimotor training volume on recovery of sensorimotor function in patients following lower limb arthroplasty.

BACKGROUND: Sensorimotor function is degraded in patients after lower limb arthroplasty. Sensorimotor training is thought to improve sensorimotor skills, however, the optimal training stimulus with regard to volume, frequency, duration, and intensity is still unknown. The aim of this study, therefore, was to firstly quantify the progression of sensorimotor function after total hip (THA) or knee (TKA) arthroplasty and, as second step, to evaluate effects of different sensorimotor training volumes. METHODS: 58 in-patients during their rehabilitation after THA or TKA participated in this prospective cohort study. Sensorimotor function was assessed using a test battery including measures of stabilization capacity, static balance, proprioception, and gait, along with a self-reported pain and function. All participants were randomly assigned to one of three intervention groups performing sensorimotor training two, four, or six times per week. Outcome measures were taken at three instances, at baseline (pre), after 1.5 weeks (mid) and at the conclusion of the 3 week program (post). RESULTS: All measurements showed significant improvements over time, with the exception of proprioception and static balance during quiet bipedal stance which showed no significant main effects for time or intervention. There was no significant effect of sensorimotor training volume on any of the outcome measures. CONCLUSION: We were able to quantify improvements in measures of dynamic, but not static, sensorimotor function during the initial three weeks of rehabilitation following TKA/THA. Although sensorimotor improvements were independent of the training volume applied in the current study, long-term effects of sensorimotor training volume need to be investigated to optimize training stimulus recommendations. TRIAL REGISTRATION: Clinical trial registration number: DRKS00007894.

Improvement of walking speed and gait symmetry in older patients after hip arthroplasty: a prospective cohort study.

BACKGROUND: Retraining walking in patients after hip or knee arthroplasty is an important component of rehabilitation especially in older persons whose social interactions are influenced by their level of mobility. The objective of this study was to test the effect of an intensive inpatient rehabilitation program on walking speed and gait symmetry in patients after hip arthroplasty (THA) using inertial sensor technology. METHODS: Twenty-nine patients undergoing a 4-week inpatient rehabilitation program following THA and 30 age-matched healthy subjects participated in this study. Walking speed and gait symmetry parameters were measured using inertial sensor device for standardized walking trials (2*20.3 m in a gym) at their self-selected normal and fast walking speeds on postoperative days 15, 21, and 27 in patients and in a single session in control subjects. Walking speed was measured using timing lights. Gait symmetry was determined using autocorrelation calculation of the cranio-caudal (CC) acceleration signals from an inertial sensor placed at the lower spine. RESULTS: Walking speed and gait symmetry improved from postoperative days 15-27 (speed, female: 3.2 and 4.5 m/s; male: 4.2 and 5.2 m/s; autocorrelation, female: 0.77 and 0.81; male: 0.70 and 0.79; P <0.001 for all). After the 4-week rehabilitation program, walking speed and gait symmetry were still lower than those in control subjects (speed, female 4.5 m/s vs. 5.7 m/s; male: 5.2 m/s vs. 5.3 m/s; autocorrelation, female: 0.81 vs. 0.88; male: 0.79 vs. 0.90; P <0.001 for all). CONCLUSIONS: While patients with THA improved their walking capacity during a 4-week inpatient rehabilitation program, subsequent intensive gait training is warranted for achieving normal gait symmetry. Inertial sensor technology may be a useful tool for evaluating the rehabilitation process during the post-inpatient period.

Can measures of limb loading and dynamic stability during the squat maneuver provide an index of early functional recovery after unilateral total hip arthroplasty?

OBJECTIVE: To investigate limb loading and dynamic stability during squatting in the early functional recovery of patients who had undergone total hip arthroplasty (THA). DESIGN: Cohort study. SETTING: Inpatient rehabilitation clinic. PARTICIPANTS: Of 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). INTERVENTIONS: Patients who had undergone THA received 2 weeks of standard inpatient rehabilitation. MAIN OUTCOME MEASURES: Interlimb 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. RESULTS: At 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). CONCLUSIONS: Patients 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.

A Method-Comparison Study Highlighting the Disparity between Osseous- and Skin-Based Measures of Foot Mobility.

PURPOSE: This study examined the validity of standard clinical measures of arch height mobility, midfoot width mobility (MWM), and foot mobility magnitude (FMM) relative to skin-based and osseous measures derived from radiographs. METHODS: Skin-based clinical indices of foot mobility were calculated from standard, caliper-based measures of foot length, midfoot width, and dorsal arch height of the left limb of 20 healthy participants (8-71 yr) during non-weight-bearing and weight-bearing. Skin-based radiographic and osseous indices were derived from concurrent anteroposterior and lateral radiographs. Agreement between skin-based clinical and skin-based radiographic measures of foot mobility with those of osseous measures was investigated using the Bland and Altman approach. RESULTS: Foot mobility indices derived from clinical measures were significantly higher (20%-50%) than skin-based radiographic measures ( P < 0.01), which were, in turn, significantly higher (200%-250%) than osseous measures ( P < 0.01). Clinical measures demonstrated significant levels of proportional bias compared with radiographic measures of foot mobility ( P < 0.01). The contribution of osseous movement to skin-based clinical measures of mobility was highly variable between individuals, ranging between 19% and 81% for arch height mobility, between 4% and 87% for MWM, and between 14% and 75% for FMM. The limits of tolerance for clinical measures of foot mobility ranged from ±3.2 mm for MWM to ±6.6 mm for measures of FMM. The limits of tolerance for skin-based clinical and skin-based radiographic measures were generally larger than osseous movement with weight-bearing. CONCLUSIONS: Skin-based measures of foot mobility, whether clinical or radiographic methods, are not interchangeable and are poor indicators of osseous mobility. Although further research regarding the utility of osseous measures is warranted, these findings strongly caution against the use of skin-based clinical measures of foot mobility in clinical and research settings.

Do increasingly unstable balance devices provide a graded challenge to bipedal stance in total hip arthroplasty patients?

BACKGROUND: Progressive balance exercises are critical to early functional rehabilitation after total hip arthroplasty (THA) but little is known regarding the challenge imposed by common balance devices. RESEARCH QUESTION: Do progressively unstable balance devices provide a graded challenge to bipedal stance during early functional rehabilitation in THA patients? METHODS: Postural control was evaluated in 42 patients (age, 63.7 ± 9.6 years; height, 1.72 ± 0.08 m and body mass, 78.9 ± 14.6 kg) approximately 3 weeks (23 ± 6 days) following unilateral primary THA. Patients were divided into two groups, based on their ability to complete a 20-second unipedal stance test (UPST) on the operated limb. A lumbar mounted inertial sensor monitored center of mass (COM) displacement during bipedal balance conditions involving three balance pads of progressive stiffness and an oscillatory platform, used in isolation and in combination with the most stable balance pad. COM displacement was normalised to bipedal stance on a hard surface. Differences between conditions and patient groups were assessed using a mixed-model analysis of variance. RESULTS: Twenty patients (48%) were able to complete the UPST on their operated limb. There was a significant effect of balance condition on COM displacement during bipedal stance (F4,160 = 82.6, p < .01). COM displacement was lowest for the oscillatory platform but increased non-linearly across the three balance pads (p < .05). There was no significant difference in COM displacement between THA patients able and unable to complete the UPST. SIGNIFICANCE: Increasingly compliant balance pads provided a progressive, though nonlinear, challenge to bipedal balance control in THA patients that was greater than that of an oscillating platform and independent of the ability to stand independently on the operated limb. These findings serve as a guide for the design of progressive training programs that enhance balance in THA patients.

A four-week minimalist shoe walking intervention influences foot posture and balance in young adults-a randomized controlled trial.

INTRODUCTION: Minimalist shoes (MS) are beneficial for foot health. The foot is a part of the posterior chain. It is suggested that interventions on the plantar foot sole also affect the upper segments of the body. This study aimed to investigate the local and remote effects along the posterior chain of four weeks of MS walking in recreationally active young adults. METHODS: 28 healthy participants (15 female, 13 male; 25.3 ± 5.3 years; 70.2 ± 11.9 kg; 175.0 ± 7.8 cm) were randomly assigned to a control- or intervention group. The intervention group undertook a four-week incremental MS walking program, which included 3,000 steps/day in the first week, increasing to 5,000 steps/day for the remaining three weeks. The control group walked in their preferred shoe (no MS). We assessed the following parameters in a laboratory at baseline [M1], after the four-week intervention [M2], and after a four-week wash-out period [M3]: Foot parameters (i.e., Foot Posture Index-6, Arch Rigidity Index), static single-leg stance balance, foot-, ankle-, and posterior chain range of motion, and muscle strength of the posterior chain. We fitted multiple hierarchically built mixed models to the data. RESULTS: In the MS group, the Foot Posture Index (b = -3.72, t(51) = -6.05, p < .001, [-4.94, 2.51]) and balance (b = -17.96, t(49) = -2.56, p = .01, [-31.54, 4.37]) significantly improved from M1 to M2, but not all other parameters (all p >.05). The improvements remained at M3 (Foot Posture Index: b = -1.71, t(51) = -2.73, p = .009, [-4,94,0.48]; balance: b = -15.97, t(49) = -2.25, p = .03, [-29.72, 2.21]). DISCUSSION: Walking in MS for four weeks might be advantageous for foot health of recreationally active young adults but no chronic remote effects should be expected.

Testing the Posterior Chain: Diagnostic Accuracy of the Bunkie Test versus the Isokinetic Hamstrings/Quadriceps Measurement in Patients with Self-Reported Knee Pain and Healthy Controls.

(1) Background: The isokinetic measurement (IM) of the leg muscles is well established but costly, whereas the Bunkie Test (BT) is a rarely investigated but easy-to-conduct functional test to evaluate the total posterior chain. Although the tests differ in aim and test structures, both have their justification in the assessment process. Therefore, this study evaluated the diagnostic accuracy of the BT and the IM. (2) Methods: 21 participants (9 female, 12 male; age, 26.2 ± 5.26 years; weight 73.8 ± 14.6 kg; height 176.0 ± 9.91 cm) and 21 patients (9 female, 12 male; age, 26.5 ± 5.56 years; weight, 72.6 ± 16.9 kg; height 177.0 ± 10.1 cm) with self-reported pain in the knee performed the IM and the BT. For IM, we calculated the ratio of the knee mean flexor/extensor peak torque (H/Q ratio) for 60°/s and 120°/s, and BT performance was measured in seconds. We classified the IM (<0.6 H/Q ratio) and the BT (leg difference ≥4 s) as binary results according to the literature. We calculated the sensitivity and specificity, which we compared with the Chi-Square test, and the 95% confidence intervals (CI). A p-value of ≤0.05 is considered significant. (3) Results: The sensitivity for the BT was 0.89, 95% CI [0.67, 0.99], and the specificity was 0.52 [0.30, 0.74]. For the IM, the sensitivity was 0.14 [0.03, 0.36] for 60°/s and 0.05 [0.00, 0.24] for 120°/s, and the specificity was 0.70 [0.46, 0.88] for 60°/s and 0.90 [0.68, 0.99] for 120°/s. The results of the Chi-Square tests were significant for the BT (χ2 (1) = 6.17, p = 0.01) but not for the IM (60°/s: χ2 (1) = 0.70, p = 0.40; 120°/s: χ2 (1) = 0.00, p = 0.97). (4) Conclusions: Patients were more likely to obtain a positive test result for the BT but not for the IM.

The Biomechanics of Musculoskeletal Tissues during Activities of Daily Living: Dynamic Assessment Using Quantitative Transmission-Mode Ultrasound Techniques.

The measurement of musculoskeletal tissue properties and loading patterns during physical activity is important for understanding the adaptation mechanisms of tissues such as bone, tendon, and muscle tissues, particularly with injury and repair. Although the properties and loading of these connective tissues have been quantified using direct measurement techniques, these methods are highly invasive and often prevent or interfere with normal activity patterns. Indirect biomechanical methods, such as estimates based on electromyography, ultrasound, and inverse dynamics, are used more widely but are known to yield different parameter values than direct measurements. Through a series of literature searches of electronic databases, including Pubmed, Embase, Web of Science, and IEEE Explore, this paper reviews current methods used for the in vivo measurement of human musculoskeletal tissue and describes the operating principals, application, and emerging research findings gained from the use of quantitative transmission-mode ultrasound measurement techniques to non-invasively characterize human bone, tendon, and muscle properties at rest and during activities of daily living. In contrast to standard ultrasound imaging approaches, these techniques assess the interaction between ultrasound compression waves and connective tissues to provide quantifiable parameters associated with the structure, instantaneous elastic modulus, and density of tissues. By taking advantage of the physical relationship between the axial velocity of ultrasound compression waves and the instantaneous modulus of the propagation material, these techniques can also be used to estimate the in vivo loading environment of relatively superficial soft connective tissues during sports and activities of daily living. This paper highlights key findings from clinical studies in which quantitative transmission-mode ultrasound has been used to measure the properties and loading of bone, tendon, and muscle tissue during common physical activities in healthy and pathological populations.

Variations in neuromuscular activity of thigh muscles during whole-body vibration in consideration of different biomechanical variables.

The intention of this study was to systematically analyze the impact of biomechanical variables in terms of different vibration frequencies, amplitudes and knee angles on quadriceps femoris and hamstring activity during exposure to whole-body vibration (WBV). 51 healthy men and women (age 55 ± 8 years) voluntary participated in the study and were randomly allocated to five different vibration-frequency groups. Each subject performed 9 static squat positions (3 amplitudes x 3 knee angles) on a side alternating vibration platform. Surface electromyography (EMG) was used to record the neuromuscular activity of the quadriceps femoris and hamstring muscles. Maximal voluntary contractions (MVCs) were performed prior to the measurements to normalize the EMG signals. A three-way mixed ANOVA was performed to analyze the different effects of the biomechanical variables on muscle activity. Depending on the biomechanical variables, EMG muscle activity ranged between 18.2 and 74.1 % MVC in the quadriceps femoris and between 5.2 and 27. 3 % MVC in the hamstrings during WBV. The highest levels of muscle activation were found at high frequencies and large amplitudes. Especially in the quadriceps femoris muscle, a WBV frequency of 30 Hz led to a significant increase in muscle activity compared to the other tested frequencies. However, it seems that knee angle is only relevant for the quadriceps femoris muscle. The results of this study should give more information for developing individual training protocols for WBV treatment in different practical applications. Key PointsWBV leads to a higher muscle activity of the quadriceps femoris than of the hamstrings.The maximum levels of muscle activity were significantly reached at high amplitude and high frequency.The knee angle only significantly affects the quadriceps femoris.Certain combinations of the biomechanical variables have similar effects on the level of muscle activity.

The effect of simulating leg length inequality on spinal posture and pelvic position: a dynamic rasterstereographic analysis.

INTRODUCTION: Leg length inequalities (LLI) are a common finding. Rasterstereography offers a non-invasive, contact-free and reliable method to detect the effects of LLIs on spinal posture and pelvic position. MATERIALS AND METHODS: A total of 115 subjects were rasterstereographically examined during different artificially created leg length inequalities (5-15 mm) using a platform. The pelvic obliquity and torsion and the lateral and frontal deviation of the spine, as well as the surface rotation, were measured. RESULTS: Changes in platform height led to an increase of the pelvic tilt and torsion. Only minor changes in the spinal posture were found by different simulated leg length inequalities. CONCLUSIONS: Our study showed that there was a correlation between an artificial leg length inequality up to 15 mm and pelvic tilt or torsion, but only minor changes in the spinal posture were measured. Further studies should investigate the effects of greater leg length inequalities on spine and pelvis.

Day-to-day reliability of two different models to quantify knee kinematics in subjects with knee osteoarthritis and healthy controls.

Results from instrumented gait analysis vary between test situations. Subject characteristics and the biomechanical model can influence the total amount of variability. The purpose of this study was to quantify reliability of gait data in general, and with respect to the applied model, and investigated population group. Reliability was compared between a functional and a predictive gait model in subjects with knee osteoarthritis and healthy controls. Day-to-day consistency for sagittal plane variables was comparable between models and population groups. Transversal plane variables relative to joint excursion showed larger inconsistency for repeated measures, even for a more sophisticated biomechanical approach. In conclusion, the presented reliability data of sagittal plane kinematics should be used for a reasonable interpretation of results derived in clinical gait analysis. Variables of the transversal plane should not be used as long as sources of error are not sufficiently minimized.

Frontal plane knee moment in clinical gait analysis: A systematic review on the effect of kinematic gait changes.

INTRODUCTION: The frontal plane knee moment (KAM1 and KAM2) derived from non-invasive three-dimensional gait analysis is a surrogate measure for knee joint load and of great interest in clinical and research settings. Many aspects can influence this measure either unintentionally or purposely in order to reduce the knee joint load to relieve symptoms and pain. All these aspects must be known when conducting a study or interpreting gait data for clinical decision-making. METHODS: This systematic review was registered with PROSPERO (CRD42020187038). Pubmed and Web of Science were searched for peer-reviewed, original research articles in which unshod three-dimensional gait analysis was undertaken and KAM1 and KAM2 were included as an outcome variable. Two reviewers independently screened articles for inclusion, extracted data and performed a methodological quality assessment using Downs and Black checklist. RESULTS: In total, 42 studies were included. Based on the independent variable investigated, these studies were divided into three groups: 1) gait modifications, 2) individual characteristics and 3) idiopathic orthopedic deformities. Among others, fast walking speeds (1) were found to increase KAM1; There were no sex-related differences (2) and genu valgum (3) reduces KAM1 and KAM2. CONCLUSION: While consistent use of terminology and reporting of KAM is required for meta-analysis, this review indicates that gait modifications (speed, trunk lean, step width), individual characteristics (body weight, age) and idiopathic orthopedic deformities (femoral or tibial torsion, genu valgum/varum) influence KAM magnitudes during walking. These factors should be considered by researchers when designing studies (especially of longitudinal design) or by clinicians when interpreting data for surgical and therapeutic decision-making.

Effects of idiopathic flatfoot deformity on knee adduction moments during walking.

INTRODUCTION: Flatfoot deformity is commonly characterized by a subtalar valgus, a low medial longitudinal arch, and abduction of the forefoot. Although flatfoot deformity has been associated with lower first (KAM1) and second (KAM2) peak knee adduction moments during walking, the biomechanical connection remains unknown. RESEARCH QUESTION: We hypothesized that hindfoot eversion, lateral calcaneal shift correlate with KAM1 and forefoot abduction and arch height with KAM2, due to the lateralization of the ground reaction force vector resulting from shifted heel and forefoot in flatfoot deformity. METHODS: Gait data from 103 children with flatfoot deformity who underwent three-dimensional gait analysis with the Oxford Foot Model were retrospectively included. Children with knee varus/valgus, in- and out-toeing were excluded. Fifteen healthy children with a rectus foot type were also collected from the database. Lateral calcaneal shift was defined as the distance between the projection of the ankle joint center onto the calcaneal axis and the midpoint of the calcaneal axis formed by the medial and lateral calcaneal markers. A subgroup of children with idiopathic flatfoot deformity that had received corrective surgery was also identified. Statistical analysis included Pearson's correlations and independent and paired t-tests (α < .05). RESULTS: When compared to a norm cohort, flatfooted children had significant lower KAM1 and KAM2 (t-test, P < .001). Lateral calcaneal shift correlated with KAM1 and KAM2 (r = 0.42, p < .001 and r = 0.32, P < .001, respectively). Arch height correlated with KAM2 (r = 0.23, p = 0.017). KAM1 and KAM2 normalized after surgery and the change in KAM1 correlated with the change in lateral calcaneal shift for children who underwent corrective surgery. SIGNIFICANCE: Lateral calcaneal shift explains the reduction of KAM1 by lateralization of the point of force application in flatfooted children. It is recommended to consider the lateral calcaneal shift when investigating KAM in gait analysis research.

The rasterstereographic-dynamic analysis of posture in adolescents using a modified Matthiass test.

The Matthiass posture test is a clinical test to detect posture changes in children and adolescents. Aim of this study was to objectify this test using a dynamic rasterstereographic measuring device. We examined 31 healthy athletes during a modified Matthiass test with a dynamic rasterstereographic measuring system. Hereby the trunk inclination, kyphosis and lordosis angle were measured. The trunk inclination decreased by about 50% of the basic value just by raising the arms. Additional weight loads of only 5% body weight (bw) resulted in significant changes of the posture (lordosis and kyphosis angle) during this test. With this rasterstereographic measuring device it seems to be possible to determine spinal posture changes under dynamic conditions. The results suggest that additional weights of 5% bw during the Matthias-test are enough to create significant deviations in posture parameters, even in healthy subjects.

Effects of a sensory-motor exercise program for older adults with osteoarthritis or prosthesis of the hip using measurements made by the Posturomed oscillatory platform.

OBJECTIVES: To assess changes in balance capacities after a 12-week sensory-motor training program for older adults with osteoarthritis or prosthesis of the hip. BACKGROUND: Sensory-motor training is recommended to help aging adults with osteoarthritis maintain activity, avoid injurious falls, and improve functioning. Up to now, however, there has been no standard training protocol for sensory-motor training. METHODS AND MEASURES: Thirty-five participants in a hip exercise group who had a mean age of 58 years (SD 12) were quasi-randomized into a training group (TG) and a control group (CG) by the month they applied for the Hip School program. The TG performed balance exercises using balance pads and received Hip School training once a week. The CG did not receive any training intervention. Balance was measured by recording center-of-pressure excursion while participants were in 1-legged stance on the oscillatory Posturomed platform. Outcome measures were the total path of center of pressure on the platform during balance recovery and the percentage of failed attempts. RESULTS: The TG had a lower percentage of failed attempts (TG 5%, CG 18%, P = .001) and required fewer balance recovery movements to maintain balance (TG: mean [SD] measurement is 59 [36] mm; CG: 96 [68] mm, P = .036] after completing the 12-week training program. After the training period, participants in the TG compensated better for perturbations in the nondisplaced medial-lateral (ML) direction (pretest [SD] measurement was 48 [18] mm; posttest, 36 [14] mm; P= .001]. CONCLUSIONS: Participants could successfully cope with more disturbances and improved their reactions to sudden displacements after training intervention. This exercise setting improves balance abilities and should be included in Hip School programs for patients with osteoarthritis.

Comparison of female foot morphology and last design in athletic footwear--are men's lasts appropriate for women?

The purpose of this study was to investigate differences between female feet and last design. Four hundred twenty-four feet and four men's running shoe lasts (U.S. women 6.0-9.5), which also are used for the manufacturing of women's shoes, were scanned in three dimensions. Six foot measures were quantified. Different foot types were classified using a cluster analysis. Comparisons were made between last measures and averaged as well as foot type specific foot measures. Differences in width measures between lasts and foot types vary substantially (0-9 mm). Length grading is similar for lasts and feet (differences < 1mm). Width grading is larger in lasts in comparison with average grading in feet (3.5-5.9 mm). Last design and grading should account for the sex-specific allometry in foot measures. The use of down-graded men's lasts for women's shoes has to be questioned. Therefore, sex-specific reference measures and wear tests should incorporate different foot types in different sizes to allow suitable implications for a proper design and grading of lasts.

Limb movement, coordination and muscle activity during a cross-coordination movement on a stable and unstable surface.

BACKGROUND: At a clinical level, the intensity of dynamic balance tasks incorporating cross-coordination movements (CCM) is typically progressed by changing the stability of the support surface on which the movement is undertaken. However, biomechanical changes in CCMs performed on stable and unstable surfaces have not yet been quantified. RESEARCH QUESTION: Do movement patterns, muscle activity, coordination strategies, knee joint loading and center of mass (CoM) movement differ during a CCM performed on stable and unstable surfaces? METHODS: Motion analysis was used to monitor limb kinematics and surface electromyography to analyze supporting leg muscle activity in sixteen healthy athletes during a single-limb support task involving a cyclic CCM on a stable and unstable surface. Angle-angle plots were used to explore coordination strategies in sagittal movement of the hip and shoulder, while differences in kinematics and muscle activity between stable and unstable conditions were evaluated using dependent t-tests (α-level = 0.05). RESULTS: CCMs on an unstable surface were performed at a slower speed (p < .05), with a more flexed posture of the support knee (p < .05) and ankle (p < .05) and resulted in reduced hip and shoulder movement of the swing limbs (p < .05). Instability increased activation of selected muscles of the ankle and knee (p < .05), resulted in a two-fold increase in the peak knee adduction moment (p < .05), and was accompanied by greater CoM movement (p < .05). Three coordination patterns of the swing limbs observed when performing CCM on a stable surface, which were mostly preserved on the unstable surface. SIGNIFICANCE: Despite adopting several stabilization strategies, CCM undertaken on an unstable surface still evoked greater excursion of the center of mass and, as such, presented a greater challenge to sensorimotor control. Adding instability in form of a swinging platform provides progression of dynamic balance CCM difficulty in an athletic population.

Transmission-Mode Ultrasound for Monitoring the Instantaneous Elastic Modulus of the Achilles Tendon During Unilateral Submaximal Vertical Hopping.

Submaximal vertical hopping capitalizes on the strain energy storage-recovery mechanism associated with the stretch-shortening cycle and is emerging as an important component of progressive rehabilitation protocols in Achilles tendon injury and a determinant of readiness to return to sport. This study explored the reliability of transmission mode ultrasound in quantifying the instantaneous modulus of elasticity of human Achilles tendon during repetitive submaximal hopping. A custom-built ultrasound transmission device, consisting of a 1 MHz broadband emitter and four regularly spaced receivers, was used to measure the axial velocity of ultrasound in the Achilles tendon of six healthy young adults (mean ± SD; age 26 ± 5 years; height 1.78 ± 0.11 m; weight 79.8 ± 13.6 kg) during steady-state unilateral hopping (2.5 Hz) on a piezoelectric force plate. Vertical ground reaction force and lower limb joint kinematics were simultaneously recorded. The potential sensitivity of the technique was further explored in subset of healthy participants (n = 3) that hopped at a slower rate (1.8 Hz) and a patient who had undergone Achilles tendon rupture-repair (2.5 Hz). Reliability was estimated using the mean-within subject coefficient of variation calculated at each point during the ground-contact phase of hopping, while cross-correlations were used to explore the coordination between lower limb kinematics ground reaction forces and ultrasound velocity in the Achilles tendon. Axial velocity of ultrasound in the Achilles tendon was highly reproducible during hopping, with the mean within-subject coefficient of variation ranging between 0.1 and 2.0% across participants. Ultrasound velocity decreased immediately following touch down (-19 ± 13 ms-1), before increasing by 197 ± 81 ms-1, on average, to peak at 2230 ± 87 ms-1 at 67 ± 3% of ground contact phase in healthy participants. Cross-correlation analysis revealed that ultrasound velocity in the Achilles tendon during hopping was strongly associated with knee (mean r = 0.98, range 0.95-1.00) rather than ankle (mean r = 0.67, range 0.35-0.79) joint motion. Ultrasound velocity was sensitive to changes in hopping frequency in healthy adults and in the surgically repaired Achilles tendon was characterized by a similar peak velocity (2283 ± 13 ms-1) but the change in ultrasound velocity (447 ± 21 ms-1) was approximately two fold that of healthy participants (197 ± 81 ms-1). Although further research is required, the technique can be used to reliably monitor ultrasound velocity in the Achilles tendon during hopping, can detect changes in the instantaneous elastic modulus of tendon with variation in hopping frequency and tendon pathology and ultimately may provide further insights into the stretch-shortening cycle and aid clinical decision concerning tendon rehabilitation protocols and readiness to return to sport.