Oxford Metrics Research Articles

Upper extremity kinematics analysis in obstetrical brachial plexus palsy

Several recent studies demonstrate that upper extremities kinematics analysis is in increasing use to assist clinical practice. We describe an upper limb kinematics analysis protocol that was first applied to a group of healthy children (to obtain normative data), and subsequently, to a child presenting with obstetrical brachial plexus palsy (OBPP) before and after surgical treatment. The protocol is based on two very simple tasks. Reflective markers are placed on the studied segments, and optoelectronic cameras three-dimensionally record the position of the markers during the course of movement. The data, collected by a Vicon system (Oxford Metrics Ltd., Oxford, UK), are analyzed by a dedicated software; this software provides coefficient of multiple correlation (CMC) for the comparison of different kinematics curves and motion amplitudes. A CMC above 0.95 was considered to be excellent, between 0.85 and 0.95 was good, and below 0.85 was poor. Twelve healthy children, average age 9.7 years (from 7 to 14 years), were analyzed. A 7-year-old patient presenting left OBPP was similarly analyzed, pre- and postoperatively, after a lateral rotation osteotomy of the humerus. The analysis of the 12 healthy children established a kinematics corridor for each task and each angle considered. Analysis of the pathological patient revealed kinematics anomalies during movement which went undetected at simple clinical examination. CMC analysis after treatment showed improvement of all movements around the shoulder, going from "poor" preoperatively to "excellent" postoperatively. Amplitudes analysis similarly demonstrated postoperative improvement, which increased from 28 to 67% according to the rotations considered, around the shoulder and elbow. The interest in these results should be confirmed by studies in a larger number of patients. Upper extremity kinematics analysis is increasingly utilized in current clinical practice. Although many problems occur because of the non-cyclical and non-automatic nature of movement, review of the literature and our preliminary results show that reproducibility is satisfactory. Interest in our work arises from helping develop a preoperative evaluation tool (providing a more global view of abnormalities) as well as a postoperative assessment one (for the quantification of movement gains obtained by surgery after humeral osteotomy). Level IV. Diagnostic retrospective study.

New Accelerometric Method to Discriminate Between Asymptomatic Subjects and Patients With Medial Knee Osteoarthritis During 3-D Gait

This study presents a new method to estimate 3-D linear accelerations at tibial and femoral functional coordinate systems. The method combines the use of 3-D accelerometers, 3-D gyroscopes and reflective markers rigidly fixed on an exoskeleton and, a functional postural calibration method. Marker positions were tracked by a six-camera optoelectronic system (VICON 460, Oxford Metrics). The purpose of this study was to determine if this method could discriminate between medial osteoarthritic and asymptomatic knees during gait. Nine patients with osteoarthritic knees and nine asymptomatic control subjects were included in this study. Eighteen parameters representing maximal, minimal, and range of acceleration values were extracted during the loading and preswing to mid-swing phase periods, and were compared in both groups. Results show good discriminative capacity of the new method. Eight parameters were significantly different between both groups. The proposed method has the potential to be used in comprehending and monitoring gait strategy in patients with osteoarthritic knee.

El patrón de movimiento en el swing de golf en jóvenes promesas

IntroductionThe golf swing is a skill that could be classified as high velocity hitting in which the main goal is that the head of the golf club reaches its maximum velocity at the moment of impact. AimsTo analyze the timing sequence of the golf swing and to identify the movement pattern of this skill. MethodsTen golf swings executed by four young players were biomechanically analyzed. Automatic capture with Vicon Oxford Metrics® was used. ResultsThe absolute values of the linear velocities were higher in men than in women. In the interval analysis, the downswing showed less variation than the backswing. Analysis of the maximum speed timing sequence revealed a different order depending on gender. In men, the sequence started with the hip movement, followed by the left elbow, left shoulder and the club head. In women, the hips and left elbow moved simultaneously, followed by the left shoulder and the club head. In contrast, the angular velocity sequences followed the same order in both genders: first the hip turn, then the shoulder turn, and finally the golf club head acceleration. These key events were more separated in the time line in men than in women. ConclusionsMovement patterns were found through discriminatory formulae in both genders, which were able to predict whether the golf swing was “good” or “bad”, taking the club head speed as the performance criterion.

Shoulder joint kinetics of the elite wheelchair tennis serve

Background:The shoulder is a key joint in wheelchair locomotion and commonly implicated in injury among virtually all wheelchair populations. In tennis, quantification of the shoulder joint kinetics that characterise the...

Influence of thigh cluster configuration on the estimation of hip axial rotation

The non-invasive estimation of hip axial rotation is prone to error. Most of this is likely to originate from soft tissue artefact (STA) at the thigh. The purpose of this study was to evaluate the relative performance of four different thigh cluster configurations. Three were novel configurations whilst one represented the Helen Hayes convention. Twenty able-bodied adults performed two alternative motor tasks involving hip axial rotation: gait and an isolated longitudinal rotation task. Kinematic data were acquired using a three-dimensional motion analysis system (VICON 512, Oxford Metrics, Oxford, England). Indirect criteria were used to evaluate STA. Hip axial rotation kinematic profiles during gait were highly sensitive to thigh cluster configuration. For the longitudinal rotation task, the various thigh clusters were only capable of estimating, at best, up to 60% of the reference amount of movement. The Helen Hayes convention was associated with the greatest degree of STA. Whilst none of the clusters represented an optimal solution, a non-rigid configuration on the distal thigh provided a more favourable alternative. The main limitation associated with this study was the absence of a true gold standard measure of hip axial rotation. Until future work provides further insight, one must remain cautious when using estimates of hip axial rotation for purposes of research or clinical interpretation.

GAIT CHANGES AFTER GREATER TROCHANTER TRANSFER IN PATIENTS WITH UNILATERAL LEGG-CALVÉ-PERTHES DISEASE

INTRODUCTION Distal and lateral transfer of the greater trochanter as a surgical treatment for trochanteric overgrowth in patients complicated with Legg-Perthes disease has been known to be effective in eliminating fatigue hip pain. However, past studies were only confined to the outcomes related to clinical and radiological changes. The purpose of this study was to evaluate the outcome of greater trochanter transfer in terms of computerized gait analysis. METHODS Cases with bilateral involvement and patients who had received any operation previously on the affected side were excluded. Nine hips in 9 patients who underwent the index operation constituted the study population. All of the patients complained of limping and fatigue pain on walking. On physical examination, Trendelenberg sign was positive in all patients. The mean age at surgery was 16.9 years (10 to 32), and the patients were followed up to at least 2 years after the operation. The mean follow-up was 39 months (27 to 52). Clinically, existence of limping, fatigue pain on walking, and Trendelenberg sign were evaluated. Radiographic evaluation was performed by measuring the radius of the femoral head, the neck-shaft angle (NSA), articulotrochanteric distance (ATD), lateral displacement, and the greater trochater overgrowth (GTOG). Center-edge (CE) angle, and the angle of the Idelberger and Frank (ACM angle) were measured to evaluate the acetabular-head relationship. Stulberg classification system was used to assess the degree of the head deformities. Three-dimensional computerized gait analysis was performed using the VICON 370 motion analysis system (Oxford Metrics Ltd., Oxford, England) before and after the operation. The pelvic obliquity angle and hip abduction/adduction angle were analyzed. The peak hip moment during single stance was recorded. RESULTS AND DISCUSSION

Evaluation Parameters for Care-Giving Motions

Quantitative evaluation parameters for care-giving motions were investigated by analyzing three-dimensional motion data of skilled and unskilled caregivers. Subjects were three skilled caregivers, each of whom had over 12 yrs of clinical experience, and four physical therapy students. We recorded a typical care-giving motion between a caregiver and a care-receiver three times for each caregiver/receiver pair with a 3-D motion analysis system (VICON system, Oxford Metrics, UK). We did time-series analyses to extract performance evaluation parameters from observed indexes such as trajectories, velocities, accelerations of the body's center of gravity (COG), jerk-cost, and impulse. The analyzed motion was lifting a patient lying on a bed into the sitting position. The skilled caregivers' operation times were shorter than those of the unskilled caregivers. The COG trajectories of skilled caregivers showed smoother and better reproducibility over the three trials, and the COG velocity curves showed a high single peak at start up. The jerk-cost and impulse of skilled caregivers were lower than those of unskilled caregivers. We found reproducibility and smoothness of movement to be good evaluation parameters for care-giving motions. The measurement indexes observed in this study should be introduced to improve evaluation of the education of unskilled caregivers.

Locomotor Strategies in Obese and Non‐obese Children

The constant strain in obese children may increase the risks of articular problems in adulthood. In the short term, obesity in children could lead to modifications of the gait pattern. The purpose of this study was to compare biomechanical parameters between obese and non-obese children during self-paced walking. Gait analysis was performed on 10 non-obese and 10 obese (body weight > 95th percentile) children between 8 and 13 years of age. Subjects were asked to walk at their own pace on a 10-m walkway with two embedded AMTI force plates (Advanced Mechanical Technology, Watertown, MA) sampling at 960 Hz. Kinematics were captured with eight VICON optoelectronic cameras (Oxford Metrics Limited, Oxford, United Kingdom) recording at 60 Hz. Obese children modified their hip motor pattern by shifting from extensor to flexor moment earlier in the gait cycle. This led obese children to significantly decrease the mechanical work done by the hip extensors during weight acceptance and significantly increase the mechanical work done by the hip flexors compared with non-obese children. The ratio of power-absorption-by-hip-flexors to power-generation-by-hip-flexors was also significantly increased in the obese group compared with non-obese children. Finally, there was a significant decrease in the single support duration in the obese group compared with non-obese. The kinetics analyzed showed that obese children could take advantage of a passive hip strategy to achieve forward progression during walking. However, considering that they are mechanically less efficient to transfer energy, walking at a natural cadence should be an appropriate exercise to reduce weight in obese children.

Biomechanical outcomes of a knee neuromuscular exercise programme among adolescent basketball players: A pilot study

Objective The objective was to test if a neuromuscular exercise programme would improve jump-shot landing technique of male adolescent basketball players. Design A non-equivalent pre-test–post-test control group experimental design was used. Setting Intervention (a 6-week neuromuscular exercise programme) took place at club practise venues and motion analysis at a biomechanics laboratory. Participants Five case and five matched control subjects participated. Main outcome measures Six high-speed (120 Hz), Oxford Metrics Vicon 370 cameras (Oxford Metrics, Oxford, UK) and a strain gauge AMTI force plate (AMTI Inc., Newton, MA, USA) synchronised were used to analyse three-dimensional (3-D) knee kinetics and kinematics of a jump-shot landing. Vertical ground reaction force, knee joint angles and negative work were calculated. Results Repeated ANOVA tests were used to compare the peak vertical ground reaction force, knee flexion, and total negative work prior to and following the exercise intervention. There was an overall significant difference for time of testing (pre-and-post intervention) and group allocation (case or control) for peak ground reaction force, knee flexion and negative working when landing from a jump-shot. Conclusion The improvements noted in the performance of case subjects suggest that neuromuscular exercises could aid in the reduction of injury rate or severity of knee injuries sustained during game play.

Kinematic Analysis of the Golf Swing in Men and Women Experienced Golfers

Golf has become an increasingly popular sport, which is enjoyed by both men and women. This paper addresses the question what differences may exist between men and women golfers. The purpose of this study is to analyze the kinematic pattern of the golf swing in both men and women experienced golfers. Seven male and five female golfers participated in the study. The measurements of kinematic data during swing were obtained with the optoelectronic system VICON (Oxford's Metric, Oxford, UK) with five cameras operating at 50 frames per second. Clubhead speed was measured using a radar system (Bell-Tronics, Ltd, Covington, USA). A Mann-Whitney test (p = 0.05) showed that the women seem to produce a wide swing with larger hip and shoulder joint rotation angles at the top of the backswing. Men flexed their left knee more during the backswing, this may promote a greater weight transfer to the right side. Nevertheless, these two kinematic patterns showed no significant differences in the clubhead speed. Men probably used their increased knee flexion to compensate for their muscular and articular suppleness which is less than that of the women. The results of this study show that there is a specific swing for women.

Influence of carrying a backpack on pelvic tilt, rotation, and obliquity in female college students

The purpose of this investigation was to examine the influence of different methods of backpack carriage on pelvic tilt, obliquity and rotation of college-age females. Thirty subjects (mean age 22.4 years) participated in three conditions: walking without a backpack, carrying a backpack unilaterally, and carrying a backpack over both shoulders. The backpack was loaded with material that comprised 15% of the subject's body weight. Gait was analyzed using the Oxford Metrics VICON Clinical Manager system while the subject walked with no backpack, with a backpack unilaterally and bilaterally. Repeated measures analysis of variance was used to determine differences in angular motion and range of motion in pelvic tilt, rotation, and obliquity in three complete trials during the three walking conditions. Angular pelvic tilt was greatest with bilateral backpack carriage compared to unilateral carriage or walking without a backpack. Angles of pelvic obliquity and rotation were not changed across the three walking conditions. Range of motion for pelvic obliquity and rotation was significantly decreased when walking with a backpack. These results suggest that backpack carriage could cause permanent posture deviations in young female college students. More study is required to evaluate compressive forces during various walking conditions.

Kinematic Analysis Of Treadmill Walking Among Individuals With Cerebral Palsy

Purpose To analyze gait kinematics of treadmill walking in individuals with cerebral palsy (CP) as compared to overground walking, in order to understand the relationship between overground and treadmill walking and to validate the use of a treadmill for gait intervention in individuals with CP. Methods A repeated measures comparison study for two groups and two walking conditions. 20 children with ambulatory spastic diplegic CP (10 males/10 females; age range 6–16 yrs, mean 11 yrs) and 20 children without disability (age/gender matched) participated in this study. All participants were tested for walking at the same speed on both walkway (10 meter) and treadmill (Biodex Gait Trainer, Biodex Medical System, Shirley, NY). The biomechanical gait parameters, including temporal-spatial and lower limb joint kinematics, were examined by using a three dimensional (3-D) motion analysis system (Vicon 512, Oxford Metrics, Tustin, CA). The walking speed was determined based on the average of three self-selected (comfortable) overground walking trials and the same speed was applied to treadmill walking trials. Results Main results from 3-D gait analysis demonstrated statistically significant differences in cadence, stride length, and lower limb joint kinematics between treadmill and overground walking. For both test groups with CP and without disability, significantly greater cadence (p<0.01 and p<0.05 respectively) and shorter stride length (p<0.05 and p<0.01 respectively) were noted during treadmill walking. In the group with CP, significantly greater peak ankle dorsi-flexion (p<0.01) and peak knee flexion (p<0.05) were observed during TM walking while significantly decreased peak ankle plantar-flexion (p<0.01) and range of motion in pelvic rotation (p<0.05) were noted. Conclusions The results indicate that the different task and environmental constraints of the treadmill walking alter the gait patterns of children with CP. The differences between the two conditions should be considered for treadmill-based gait experiments and clinical intervention.

A Hamstring Fatiguing Protocol Has No Effect On Knee Joint Moments During Landing

Hamstring activation has been shown to decrease anterior tibial translation, and thus, might decrease stress to the anterior cruciate ligament (ACL). If this muscle activation is diminished from fatigue, the ACL could be predisposed to injury. The effects of fatiguing the hamstrings on knee joint moments during a functional task could provide insight into the prevention and treatment of ACL injuries. PURPOSE To compare flexion, valgus, and internal rotation moments of the knee during single-leg landing from a height of 60 cm before and after a hamstring fatiguing protocol. METHODS Eight males (25±4.1 yrs.) and eight females (25±2.2 yrs.) performed 5 trials of single-leg landing on the dominant limb from a height of 60 cm and then participated in a hamstring fatiguing protocol of the same limb. Immediately following the fatiguing protocol, subjects were asked to repeat the 5 trials of single-leg landing. Knee joint moments (flexion, valgus, and internal rotation) were calculated from the raw ground reaction forces and the kinematic values from a 10 camera motion analysis system (VICON, V624, Oxford Metrics Ltd., Oxford, UK). The effects of gender and hamstring fatigue on knee joint moments were analyzed using three two-way ANOVAs with repeated measures on hamstring fatigue state. RESULTS A significant interaction for hamstring state by gender on knee internal rotation moments (F1,14 = 5.08, P = .041) was seen during landing. However, no individual differences existed (P >0.05). There were no differences in knee flexion or valgus moments between genders or hamstring states (P >0.05). CONCLUSIONS Gender and hamstring fatigue state had no significant effect on knee flexion, valgus, or internal rotation moments during a single-leg landing.

A Hamstring Fatiguing Protocol Has No Effect On Knee Joint Moments During Landing

Hamstring activation has been shown to decrease anterior tibial translation, and thus, might decrease stress to the anterior cruciate ligament (ACL). If this muscle activation is diminished from fatigue, the ACL could be predisposed to injury. The effects of fatiguing the hamstrings on knee joint moments during a functional task could provide insight into the prevention and treatment of ACL injuries. PURPOSE To compare flexion, valgus, and internal rotation moments of the knee during single-leg landing from a height of 60 cm before and after a hamstring fatiguing protocol. METHODS Eight males (25±4.1 yrs.) and eight females (25±2.2 yrs.) performed 5 trials of single-leg landing on the dominant limb from a height of 60 cm and then participated in a hamstring fatiguing protocol of the same limb. Immediately following the fatiguing protocol, subjects were asked to repeat the 5 trials of single-leg landing. Knee joint moments (flexion, valgus, and internal rotation) were calculated from the raw ground reaction forces and the kinematic values from a 10 camera motion analysis system (VICON, V624, Oxford Metrics Ltd., Oxford, UK). The effects of gender and hamstring fatigue on knee joint moments were analyzed using three two-way ANOVAs with repeated measures on hamstring fatigue state. RESULTS A significant interaction for hamstring state by gender on knee internal rotation moments (F1,14 = 5.08, P = .041) was seen during landing. However, no individual differences existed (P >0.05). There were no differences in knee flexion or valgus moments between genders or hamstring states (P >0.05). CONCLUSIONS Gender and hamstring fatigue state had no significant effect on knee flexion, valgus, or internal rotation moments during a single-leg landing.

Scoliosis in Cystic Fibrosis

This is a retrospective study of all the patients registered with the Yorkshire Regional Cystic Fibrosis unit from 1982 to 1997. Of the 316 patients, there were 184 adults (age 17 years and above) and 132 children (age 0-6 years). This study was aimed at determining the prevalence of scoliosis in people with cystic fibrosis and describes the characteristics and progression of scoliosis in these patients and highlights predictive factors, which account for high prevalence of scoliosis in this condition. Two previous North American studies (1978 and 1982) have indicated a high prevalence of scoliosis in patients with cystic fibrosis. The patients were divided into 3 groups based on their chronologic age as on January 1998. Chest, abdomen, and whole spine radiographs were studied for the presence of any spinal deformity, and measurements were made using the Oxford Cobbmeter (Oxford Metrics). The extent, apex, and the side of the curves were described. The disease-specific scores, ie, Chrispin-Norman score (score for radiologic severity of lung disease) and Shwachman score (score for general condition), were noted from the patient follow-up database maintained by the Regional Cystic Fibrosis Unit. Multiple linear regression analysis was used to study the correlation between Cobb angle and the previously mentioned scores. In the 4- to 16-year age group, the prevalence of scoliosis was 15.6%, which is 20 times the prevalence in 15,793 school children with a similar age and sex distribution from the same geographic area. The majority of curves were single-thoracic, apical around T6-T8 with no side predilection. In the adult population (above 16 years), the prevalence was 9.8%, which is higher than that of the general population. These curves were thoracic, apical around T7-T8, and approximately two thirds of them were right-sided. Infantile curves are described for the first time in our study; these tend to be nonprogressive, right-sided, upper thoracic curves. Our study shows a high prevalence of scoliosis in people with cystic fibrosis. These are benign short midthoracic curves, apical between T6-T8 with no side predilection.

Dynamic hip flexion contractures.

Stretching exercises of the hip flexors may be an easy but often ignored component of rehabilitation programs to improve gait, especially for the elderly. Reduced range of motion at the hip can be difficult to detect due to the significant amount of soft tissue surrounding the joint and to movements at the pelvis, which may subtly mask reduced hip extension. Although hip flexion contractures can be detected by bedside examinations such as the Thomas test, three-dimensional gait analysis best captures dynamic range of motion limitations. Walking is perhaps the only regular daily activity whereby the hip is fully extended, and indeed, hip flexion contractures are associated with immobility.1 Older adults who do not walk regularly may be particularly vulnerable to developing hip flexion contractures. Even for healthy older adults with no musculoskeletal defects, three-dimensional gait analysis has demonstrated reduced hip extension during walking compared with young adults.2 Whereas inability to walk can produce hip flexion contractures, hip flexion contractures can in turn hinder normal gait patterns. Hip flexion contractures can be compensated during gait through increased anterior pelvic tilting, decreased contralateral step length, and increased knee flexion. In one study examining the dynamic relationship between hip flexion contractures and their compensatory mechanisms, reduced hip extension was significantly correlated with anterior pelvic tilting and reduced contralateral step length.3 The graphs in Figures 1 and 2 depict the hip flexion and extension range and pelvic tilting during one gait cycle of a 92-yr-old male resident of an assisted-living facility. The x-axes are in units of frame samples (120 samples/sec) and the y-axes are in angle degrees based on a standardized protocol for measuring sagittal plane hip and pelvic positions and motions (Vicon Clinical Manager, Oxford Metrics). The solid line represents baseline walking, and the dotted line represents the patient’s gait after completion of a 10-wk hip extension stretching program. The hip extension stretching resulted not only in improved peak hip extension but also in improvements in variables that compensate for reduced hip extension, namely, anterior pelvic tilting and step length. For this patient, a 6-degree improvement in peak hip extension was associated with a 3-degree improvement in anterior pelvic tilting, a 0.30-m increase in step length (29% increase from baseline), and a 0.32-m/sec increase (37%) in self-determined comfortable gait velocity from baseline.Figure 1:: Hip flexion extension during one gait cycle.Figure 2:: Pelvic tilt during one gait cycle.The above case and graphs are an example of how targeting one specific deficit (i.e., reduced hip flexion) can lead to improvements in other gait deficits (i.e., anterior pelvic tilt and contralateral step length) and bring about a more efficient gait pattern (as seen with increased gait velocity).

Wie reliabel sind Informationen aus der 3D-Ganganalyse?

The aim of the present study was to collect preliminary data to determine the test-retest reliability in healthy subjects using 3-dimensional computerised gait analysis. Ten healthy subjects (6 females, 4 males) were tested using a 3-dimensional computerized gait analysis system (VICON 512, Oxford Metrics). There were two trials within a 2-hour period in which kinetic, kinematic and time-distance data were collected. Markers were removed after the first trial and reapplied for the second trial and Pearson's correlation coefficients were calculated. The correlation coefficients were all positive and high for time-distance (r = 0.86-0.99), sagittal plane kinematics (r = 0.86-0.98) and power (r = 0.90-0.98) parameters, indicating excellent reliability of these measures. Correlation coefficients for frontal and transverse plane kinematics were lower (r = 0.59-0.89). The lowest correlation coefficient values were obtained for transverse plane measures at the hip joint indicating poor reliability of this measure in healthy subjects. The results suggest excellent test-retest reliability using 3-dimensional computerized gait analysis, especially in the sagittal plane. Therefore this method is a very valuable tool in the analysis as well as in the outcome evaluation of conservative and operative procedures in movement disorders

The Effect of Different Insole Surfaces on Running Biomechanics, Muscle Recruitment and Perceived Comfort

0419 PURPOSE: The aim of this study was to investigate the effect of a rough or smooth surface of the same insole on running biomechanics, muscle recruitment and perceived comfort. METHODS: Twelve injury free runners ran 10 trials (5 at a self-selected speed and 5 at a controlled running speed) on either the rough (RI) or the smooth (SI) surface of the same insole in a randomised fashion. Kinetic, kinematic and temporal distance parameters were collected using the Oxford Metric Vicon System (Helen Hayes modified marker set). Electromyography (EMG) data were collected (Noraxon telemetry system – 1920 Hz), from the Lateral Gastrocnemius (LG), Rectus Femoris (RF), Biceps Femoris (BF), Tibialis Anterior (TA) and Vastus Lateralis (VL) muscles. EMG data (100ms prior to heelstrike) were filtered (10–200Hz) and the root mean square (RMS) amplitude over periods of 50ms was calculated. EMG was expressed as a percentage of the peak RMS EMG. Rating of perceived comfort (RPC) (VAS 0–10) was measured during a 400m run (85% of 5km time trial pace). RESULTS: There was a slower self-selected speed in the RI compared to the SI (RI: 2.99 ± 0.24 m/s, SI: 3.06 ± 0.24 m/s; p = 0.048). There were no differences in kinetic and kinematic variables between RI and SI conditions. Rectus Femoris recruitment was lower in the RI compared with the SI condition (RI: 1.47 ± 0.94 %, SI: 1.68 ± 1.13 %; p = 0.029). The RPC was similar in the RI (3.50 ± 2.50) and the SI (4.75 ± 2.18) (p = 0.056) conditions. CONCLUSION: Running on the rougher compared to the smooth surface of the same insole reduces self-selected running speed and recruitment of the Rectus Femoris muscle just prior to heel strike.

The Effect of Different Insole Surfaces on Running Biomechanics, Muscle Recruitment and Perceived Comfort

0419 PURPOSE: The aim of this study was to investigate the effect of a rough or smooth surface of the same insole on running biomechanics, muscle recruitment and perceived comfort. METHODS: Twelve injury free runners ran 10 trials (5 at a self-selected speed and 5 at a controlled running speed) on either the rough (RI) or the smooth (SI) surface of the same insole in a randomised fashion. Kinetic, kinematic and temporal distance parameters were collected using the Oxford Metric Vicon System (Helen Hayes modified marker set). Electromyography (EMG) data were collected (Noraxon telemetry system – 1920 Hz), from the Lateral Gastrocnemius (LG), Rectus Femoris (RF), Biceps Femoris (BF), Tibialis Anterior (TA) and Vastus Lateralis (VL) muscles. EMG data (100ms prior to heelstrike) were filtered (10–200Hz) and the root mean square (RMS) amplitude over periods of 50ms was calculated. EMG was expressed as a percentage of the peak RMS EMG. Rating of perceived comfort (RPC) (VAS 0–10) was measured during a 400m run (85% of 5km time trial pace). RESULTS: There was a slower self-selected speed in the RI compared to the SI (RI: 2.99 ± 0.24 m/s, SI: 3.06 ± 0.24 m/s; p = 0.048). There were no differences in kinetic and kinematic variables between RI and SI conditions. Rectus Femoris recruitment was lower in the RI compared with the SI condition (RI: 1.47 ± 0.94 %, SI: 1.68 ± 1.13 %; p = 0.029). The RPC was similar in the RI (3.50 ± 2.50) and the SI (4.75 ± 2.18) (p = 0.056) conditions. CONCLUSION: Running on the rougher compared to the smooth surface of the same insole reduces self-selected running speed and recruitment of the Rectus Femoris muscle just prior to heel strike.

Postural reaction during maximum grasping maneuvers using a hand dynamometer in healthy subjects

The purpose of this study was to quantitatively evaluate spontaneous body sway during maximum grasping maneuver with a hand dynamometer, which we sometimes encounter in clinical practice. The postural reaction of the whole body during maximum grasping maneuver was analyzed in 26 right-handed healthy male volunteers using a three-dimensional motion analysis system (VICON system, Oxford Metrics, UK) and force plates. We found that the gravity center of the body moved toward the grasping side. Also, voluntary rotation of the trunk and flexion of the neck was observed during grasping on each side.