Total Rotation Research Articles

Motion at the Tibial and Polyethylene Component Interface in a Mobile-Bearing Total Ankle Replacement.

Normal biomechanics of the ankle joint includes sagittal as well as axial rotation. Current understanding of mobile-bearing motion at the tibial-polyethylene interface in total ankle arthroplasty (TAA) is limited to anterior-posterior (AP) motion of the polyethylene component. The purpose of our study was to define the motion of the polyethylene component in relation to the tibial component in a mobile-bearing TAA in both the sagittal and axial planes in postoperative patients. Patients who were a minimum of 12 months postoperative from a third-generation mobile-bearing TAA were identified. AP images were saved at maximum internal and external rotation, and the lateral images were saved in maximum plantarflexion and dorsiflexion. Sagittal range of motion and AP translation of the polyethylene component were measured from the lateral images. Axial rotation was determined by measuring the relative position of the 2 wires within the polyethylene component on AP internal and external rotation imaging. This relationship was compared to a table developed from fluoroscopic images taken at standardized degrees of axial rotation of a nonimplanted polyethylene with the associated length relationship of the 2 imbedded wires. Sixteen patients were included in this investigation, 9 (56%) were male and average age was 68 (range, 49-80) years. Time from surgery averaged 25 (range, 12-38) months. Total sagittal range of motion averaged 23±9 (range, 9-33) degrees. Axial motion for total internal and external rotation of the polyethylene component on the tibial component averaged 6±5 (range, 0-18) degrees. AP translation of the polyethylene component relative to the tibial component averaged 1±1 (range, 0-3) mm. There was no relationship between axial rotation or AP translation of the polyethylene component and ankle joint range of motion (P > .05). To our knowledge, this is the first investigation to measure axial and sagittal motion of the polyethylene component at the tibial implant interface in patients following a mobile-bearing TAA. Based on outcome scores and range-of-motion measurements, we believe the patients in this study are a representative cross section of subjects compared to other TAA research results. The results from this investigation indicate the potential for a mobile-bearing TAA to fall within the parameters of normal polyaxial ankle motion. The multiplanar articulation in a mobile-bearing TAA may reduce excessively high peak pressures during the complex dynamic tibial and talar motion, which may have a positive influence on gait pattern, polyethylene wear, and implant longevity. Level IV, case series.

Comparable Stability of Cemented vs Press-Fit Placed Stems in Revision Total Knee Arthroplasty With Mild to Moderate Bone Loss: 6.5-Year Results From a Randomized Controlled Trial With Radiostereometric Analysis

BackgroundShort-term stability after revision total knee arthroplasty (TKA) with either fully cemented or hybrid-placed implants is comparable. Interestingly, implant micromotion >1 mm/degree occurred with both techniques which might increase the risk of loosening in the midterm or long-term. Therefore, the present study investigated midterm stability and clinical results of fully cemented vs hybrid-placed revision TKA, with mild to moderate bone loss, using radiostereometric analysis (RSA). MethodsThis study involves the prolonged follow-up of a previous randomized controlled trial. RSA images taken at baseline, 6 weeks, 3 and 6 months, and 1, 2 and 6.5 years of follow-up were analyzed. Stability of the femoral and tibial implants was evaluated using total translation and rotation, based on the micromotion determined with model-based RSA. ResultsOf the 30 patients who completed the 2-year follow-up in the original randomized controlled trial, 23 (12 cement, 11 hybrid) were available for follow-up at 6.5-year (range 5.4-7.3). There were no differences in median total translation and rotation of the femoral and tibial components between the 2 groups, and none of the clinical scores differed between the groups. Interestingly, in the group with cemented stems, 5 tibia implants showed >1 mm/degree micromotion compared to none in the hybrid group. ConclusionThere was no difference in median micromotion and clinical outcome between fully cemented and hybrid-placed revision TKA 6.5 years postoperatively. Two femur components showed progressive migration over time whereas tibia components migrate especially in the first year followed by a stable situation. Whether this will lead to loosening and re-revisions remains to be investigated.

Acute effects of scapular Kinesio Taping® on shoulder rotator strength, ROM and acromiohumeral distance in asymptomatic overhead athletes.

There is limited information in the literature that shows whether scapular taping has an effect on the acromiohumeral distance (AHD) and shoulder functions. The aim of this study was to investigate the acute effects of scapular Kinesio Taping® on shoulder internal rotation (IR) and external rotation (ER) strength, IR and ER range of motion (ROM) and AHD in asymptomatic overhead athletes. Forty-one volleyball athletes (24 men, 17 women; mean age: 16.1±1.5 years, body mass: 66.5±9.6 kg, body height: 179.6±8.4 cm, Body Mass Index: 20.5±2.3 kg/m2, time participating in overhead sports activity: 6.2±1.4 h/week, experience in sport: 4.1±2.4 years) were included in this study. Shoulder IR and ER ROM, total rotation ROM, AHD, shoulder isometric IR and ER strength and ER:IR strength ratio of the dominant side were tested before and after taping. Scapular taping increased the shoulder IR (P<0.001) and total ROM (P<0.001), AHD (P<0.001), shoulder IR (P=0.002) and ER (P=0.006) strength. ER ROM and ER:IR ratio did not change after taping (P=0.26, P=0.98, respectively). The results of this study suggest that scapular taping could be an effective method for enhancing the acromiohumeral distance, shoulder rotator strength and range of motion. Therefore, scapular taping could be recommended for not only in the asymptomatic athletes' shoulder exercise training but also in the prevention of subacromial impingement syndrome.

No effect of additional screw fixation of a cementless, all-polyethylene press-fit socket on migration, wear, and clinical outcome

Background and purpose — Additional screw fixation of the all-polyethylene press-fit RM cup (Mathys) has no additional value for migration, in the first 2 years after surgery. However, the medium-term and long-term effects of screw fixation remain unclear. We therefore evaluated the influence of screw fixation on migration, wear, and clinical outcome at 6.5 years using radiostereometric analysis (RSA).Patients and methods — This study involved prolonged follow-up from a previous randomized controlled trial (RCT). We analyzed RSA radiographs taken at baseline and at 1-, 2-, and 6.5-year follow-up. Cup migration and wear were assessed using model-based RSA software. Wear was calculated as translation of the femoral head model in relation to the cup model. Total translation, rotation, and wear were calculated mathematically from results of the orthogonal components.Results — 27 patients (15 with screw fixation and 12 without) were available for follow-up at 6.5 (5.6–7.2) years. Total translation (0.50 mm vs. 0.56 mm) and rotation (1.01 degrees vs. 1.33 degrees) of the cup was low, and was not significantly different between the 2 groups. Wear increased over time, and was similar between the 2 groups (0.58 mm vs. 0.53 mm). Wear rate (0.08 mm/year vs. 0.09 mm/year) and clinical outcomes were also similar.Interpretation — Our results indicate that additional screw fixation of all-polyethylene press-fit RM cups has no additional value regarding medium-term migration and clinical outcome. The wear rate was low in both groups.

Temporal coupled mode analysis of one-dimensional magneto-photonic crystals with cavity structures

In this paper, we propose the time-dependent coupled mode analysis of one-dimensional magneto-photonic crystals including one, two or multiple defect layers. The performance of the structures, namely the total transmission, Faraday rotation and ellipticity, is obtained using the proposed method. The results of the developed analytic approach are verified by comparing them to the results of the exact numerical transfer matrix method. Unlike the widely used numerical method, our proposed analytic method seems promising for the synthesis as well as the analysis purposes. Moreover, the proposed method has not the restrictions of the previously examined analytic methods.

Effects of wheelchair Tai Chi on physical and mental health among elderly with disability

ABSTRACTA 12-week Wheelchair Tai Chi 10 Form (WTC10) intervention was conducted among elderly with disability to examine the effect of this WTC10 intervention on selected physical and mental health variables. Thirteen (age 87.23 ± 6.71) in the WTC10 intervention group and 15 (age 89.73 ± 6.31) in the control group completed the study. Independent t-tests and paired t-tests were employed to examine the differences between groups and within groups, respectively, at pretest and post-test. The WTC10 intervention group showed significant improvements in systolic and diastolic blood pressure, shoulder external rotation, left trunk rotation and total trunk rotation after the intervention. A 12-week WTC10 intervention had positive effects on blood pressure, range of motion at the shoulder and trunk, physical activity, and mental health among the elderly with disability. WTC10 is a feasible and safe exercise for the elderly with disability.

Movement Patterns and Muscular Function Before and After Onset of Sports-Related Groin Pain: A Systematic Review with Meta-analysis.

BackgroundSports-related groin pain (SRGP) is a common entity in rotational sports such as football, rugby and hockey, accounting for 12–18 % of injuries each year, with high recurrence rates and often prolonged time away from sport.ObjectiveThis systematic review synthesises movement and muscle function findings to better understand deficits and guide rehabilitation.Study SelectionProspective and retrospective cross-sectional studies investigating muscle strength, flexibility, cross-sectional area, electromyographic activation onset and magnitude in patients with SRGP were included.Search MethodsFour databases (MEDLINE, Web of Knowledge, EBSCOhost and EMBASE) were searched in June 2014. Studies were critiqued using a modified version of the Downs and Black Quality Index, and a meta-analysis was performed.ResultsSeventeen studies (14 high quality, 3 low quality; 8 prospective and 9 retrospective) were identified. Prospective findings: moderate evidence indicated decreased hip abduction flexibility as a risk factor for SRGP. Limited or very limited evidence suggested that decreased hip adduction strength during isokinetic testing at ~119°/s was a risk factor for SRGP, but no associations were found at ~30°/s or ~210°/s, or with peak torque angle. Decreased hip abductor strength in angular velocity in ~30°/s but not in ~119°/s and ~210°/s was found as a risk factor for SRGP. No relationships were found with hip internal or external rotation range of movement, nor isokinetic knee extension strength. Decreased isokinetic knee flexion strength also was a potential risk factor for SRGP, at a speed ~60°/s. Retrospective findings: there was strong evidence of decreased hip adductor muscle strength during a squeeze test at 45°, and decreased total hip external rotation range of movement (sum of both legs) being associated with SRGP. There was strong evidence of no relationship to abductor muscle strength nor unilateral hip internal and external rotation range of movement. Moderate evidence suggested that increased abduction flexibility and no change in total hip internal rotation range of movement (sum of both legs) were retrospectively associated with SRGP. Limited or very limited evidence (significant findings only) indicated decreased hip adductor muscle strength during 0° and 30° squeeze tests and during an eccentric hip adduction test, but a decrease in the isometric adductors-to-abductors strength ratio at speed 120°/s; decreased abductors-to-adductors activation ratio in the early phase in the moving leg as well as in all three phases in the weight-bearing leg during standing hip flexion; and increased hip flexors strength during isokinetic and decrease in transversus abdominis muscle resting thickness associated with SRGP.ConclusionsThere were a number of significant movement and muscle function associations observed in athletes both prior to and following the onset of SRGP. The strength of findings was hampered by the lack of consistent terminology and diagnostic criteria, with there being clear guides for future research. Nonetheless, these findings should be considered in rehabilitation and prevention planning.

Shadow of rotating regular black holes

We study the shadows cast by the different types of rotating regular black holes viz. Ay\'on-Beato-Garc\'ia {(ABG)}, Hayward, and Bardeen. These black holes have in addition to the total mass ($M$) and rotation parameter ($a$), different parameters as electric charge ($Q$), deviation parameter ($g$), and magnetic charge ($g_{*}$), respectively. Interestingly, the size of the shadow is affected by these parameters in addition to the rotation parameter. We found that the radius of the shadow in each case decreases monotonically and the distortion parameter increases when the value of these parameters increase. A comparison with the standard Kerr case is also investigated. We have also studied the influence of the plasma environment around regular black holes to discuss its shadow. The presence of the plasma affects the apparent size of the regular black hole's shadow to be increased due to two effects (i) gravitational redshift of the photons and (ii) radial dependence of plasma density.

Evaluation Of Reliability And Validity Of A New Device To Measure Knee Rotation

Rotational laxity of knee is known as the one of the intrinsic risk factors of anterior cruciate ligament (ACL) injury. However, there is no simple device to measure knee rotation. The “RotorMeter” is a newly developed, simple, non-invasive, external device that is specifically designed to measure the lower leg rotation relative to the femur in vivo. PURPOSE: To determine the reliability and validity of the RotorMeter. METHODS: Two measurements were made with the RotorMeter at 90° of knee flexion and 90° of hip flexion applying 8 Nm torque by 2 independent examiners in 14 healthy female subjects (21.1±1.2 yrs, 28 knees). Image analysis to obtain the rotation of the right lower leg was simultaneously carried out. Statistical analysis was performed using intra-class correlation coefficients (ICC, intra-examiner and inter-examiner) and Pearson’s correlation coefficient between the 2 methods. RESULTS: Total (internal + external) knee rotation ranged from 100.0° to 105.7° (standard error of measurement ranged from 2.3° to 3.7°) by the RotorMeter and was 62.2±8.24° by the image analysis. Intra-examiner ICC(1,1) results were 0.705 and 0.721, and inter-examiner ICC(2,2) was 0.828. The correlation coefficient between the results of RoterMeter and image analysis was 0.875 (significant at P < 0.05). CONCLUSIONS: The RoterMeter was found to be a reliable and valid measurement instrument concerning knee rotation. It is easy to perform and might be used in a wide field to measure knee rotation. But the deformation of soft tissue and the movement of subtalar joint should be considered. This study was supported by a Grant-in Aid Exploratory Research from NUHW (2013-A-30).

Baseball Pitcher Shoulder Internal and External Rotational Range of Motion as an Injury Risk Indicator

Prior research has demonstrated that pitchers with a deficit greater than five degrees in total rotation passive range of motion (TRM) in the dominant shoulder had a 2.6 times higher risk of injury to their elbow. PURPOSE: To evaluate the clinical utility of total range of motion (TRM), global internal rotation deficits (GIRD), and differences between rotational active and passive range of motion (A/PROM) as injury predictors among intercollegiate pitchers. METHODS: Fifteen division I baseball pitchers (age 19.4 ± 1.06 years; BMI 26.71 ± 1.92kg/m2) were tested during a competitive season. Range of motion measurements included active and passive external and internal rotation at 90° abduction in the scapular plane. TRM, GIRD, and A/PROM were compared between injured and uninjured players. RESULTS: Overall upper and lower body injury rate was 46.6% (seven out of 15). Elbow injury rate was 13.3% (two out of 15). Average difference in GIRD was 12.2 ± 13.92, in TRM was 23.07 ± 13.92, and in A/PROM was 37.13± 15.40. There were no statistically significant differences in TRM, GIRD, or A/PROM between the injured and non-injured groups. Pearson Chi-square analysis revealed no association between injury frequency with GIRD measurements >20 degrees for injured and uninjured. All participants of this study had TRM measurements > 5 degrees and A/PROM difference of >10 degrees. A/PROM difference of >40 degrees was analyzed between injured and uninjured with no significant difference. CONCLUSIONS: All pitchers in this study were at risk for elbow injury; two sustained injuries. Although not statistically significant, probably due to sample size, this is a much higher injury rate (13.3%) than previous research predicts (2.6%). The authors hypothesize it may be more appropriate to evaluate the difference of A/PROM to identify a motor control impairment as a cause of injury. Future studies should investigate the effects of upper extremity motor control on injury frequency among pitchers.

Cost-Effectiveness of Reverse Total Shoulder Arthroplasty Versus Arthroscopic Rotator Cuff Repair for Symptomatic Large and Massive Rotator Cuff Tears

To compare the cost-effectiveness within the United States health care system of arthroscopic rotator cuff repair versus reverse total shoulder arthroplasty in patients with symptomatic large and massive rotator cuff tears without cuff-tear arthropathy. An expected-value decision analysis was constructed comparing the costs and outcomes of patients undergoing arthroscopic rotator cuff repair and reverse total shoulder arthroplasty for large and massive rotator cuff tears (and excluding cases of cuff-tear arthropathy). Comprehensive literature search provided input data to extrapolate costs and health utility states for these outcomes. The primary outcome assessed was that of incremental cost-effectiveness ratio (ICER) of reverse total shoulder arthroplasty versus rotator cuff repair. For the base case, both arthroscopic rotator cuff repair and reverse total shoulder were superior to nonoperative care, with an ICER of $15,500/quality-adjusted life year (QALY) and $37,400/QALY, respectively. Arthroscopic rotator cuff repair was dominant over primary reverse total shoulder arthroplasty, with lower costs and slightly improved clinical outcomes. Arthroscopic rotator cuff repair was the preferred strategy as long as the lifetime progression rate from retear to end-stage cuff-tear arthropathy was less than 89%. However, when the model was modified to account for worse outcomes when reverse shoulder arthroplasty was performed after a failed attempted rotator cuff repair, primary reverse total shoulder had superior outcomes with an ICER of $90,000/QALY. Arthroscopic rotator cuff repair-despite high rates of tendon retearing-for patients with large and massive rotator cuff tears may be a more cost-effective initial treatment strategy when compared with primary reverse total shoulder arthroplasty and when assuming no detrimental impact of previous surgery on outcomes after arthroplasty. Clinical judgment should still be prioritized when formulating treatment plans for these patients. LEVELOF EVIDENCE: Level II, economic decision analysis.

Characterization of the eigenmode frequency spectrum influenced by the polarization states and light field distribution in a nonplanar ring resonator.

We present the evolution of the eigenmode frequency spectrum in a nonplanar ring resonator based on the Jones matrix and the Fresnel-Kirchhoff diffraction integral. Taking the modes TEM(q+1)01 and TEMq10 with different polarization states as examples, we numerically derive the frequency difference between them versus the folding angles of the resonator by considering the polarization and the light field distribution of the eigenmodes synchronously. It can be found that the extreme values of frequency difference between TEM(q+1)01 and TEMq10 are particularly affected by the polarization states of the eigenmode, and the locations of these consecutive extreme values correspond to the total image rotation angle with values of the integer multiple of 90°. Moreover, the influence of the resonator structure on the frequency difference of eigenmodes with the identical polarization state is also analyzed. The results prove that the frequency difference between the fundamental mode and higher order modes declines with the increase of the spherical mirrors' radius of curvature but increases with the augmentation of the resonator's total length. These interesting findings are important for the mode selection in high-accuracy ring laser gyroscopes with nonplanar structure by modulating the polarization states and the light field distribution of the eigenmodes to control the frequency difference between them.

Neural Excitability and Joint Laxity in Chronic Ankle Instability, Coper, and Control Groups.

Neuromuscular and mechanical deficiencies are commonly studied in participants with chronic ankle instability (CAI). Few investigators have attempted to comprehensively consider sensorimotor and mechanical differences among people with CAI, copers who did not present with prolonged dysfunctions after an initial ankle sprain, and a healthy control group. To determine if differences exist in spinal reflex excitability and ankle laxity among participants with CAI, copers, and healthy controls. Case-control study. Research laboratory. Thirty-seven participants with CAI, 30 participants categorized as copers, and 26 healthy control participants. We assessed spinal reflex excitability of the soleus using the Hoffmann reflex protocol. Participants' ankle laxity was measured with an instrumented ankle arthrometer. The maximum Hoffmann reflex : maximal muscle response ratio was calculated. Ankle laxity was measured as the total displacement in the anterior-posterior directions (mm) and total rotation in the inversion and eversion directions (°). Spinal reflex excitability was diminished in participants with CAI compared with copers and control participants (P = .01). No differences were observed among any of the groups for ankle laxity. Changes in the spinal reflex excitability of the soleus that likely affect ankle stability were seen only in the CAI group, yet no mechanical differences were noted across the groups. These findings support the importance of finding effective ways to increase spinal reflex excitability for the purpose of treating neural excitability dysfunction in patients with CAI.

Widespread Pressure Pain Hyperalgesia in Chronic Nonspecific Neck Pain with Neuropathic Features: A Descriptive Cross-Sectional Study

Neck pain has an elevated prevalence worldwide. Most people with neck pain are diagnosed as nonspecific neck pain patients. Poor recovery in neck disorders, as well as high levels of pain and disability, are associated with widespread sensory hypersensitivity. Nevertheless, there is controversy regarding the presence of widespread hyperalgesia in chronic nonspecific neck pain (CNSNP); this lack of agreement could be due to the presence of different pathophysiological mechanisms in CNSNP. To determinate differences in pressure pain thresholds (PPTs) over extracervical and cervical regions, and differences in cervical range of motion (ROM) between patients with CNSNP with and without neuropathic features (NF and No-NF, respectively). In addition, this study expected to observe correlations in these 2 types of CNSNP of psychosocial factors with PPTs and with cervical ROM separately. Descriptive, cross-sectional study. A hospital physiotherapy outpatient department. This research involved 53 patients with CNSNP that had obtained a Self-completed Leeds Assessment of Neuropathic Symptoms and Signs pain scale (S-LANSS) score = 12 (pain with NF, NF group); 54 that had obtained a S-LANSS score < 12 (pain with No-NF, No-NF group), and 53 healthy controls (control group, CG). Measures included: PPTs (suboccipital muscle, upper fibers trapezius muscle, lateral epicondyle, and anterior tibial muscle), cervical ROM (flexion, extension, rotation, and latero-flexion), pain intensity (Visual Analog Scale [VAS]), neck disability index (NDI), kinesiophobia (Tampa Scale of Kinesiophobia-11 [TSK-11]), and Pain Catastrophizing Scale (PCS). A statistically significant effect was observed for the group factor in all assessed measures (P < 0.01). Both CNSNP groups showed statistically significant differences compared to the CG for PPTs in the cervical region (suboccipital and upper fibers trapezius muscles), but only the NF group demonstrated statistically significant differences for PPTs in the lateral epincondyle and anterior tibial muscle when compared to the CG or No-NF group. The largest statistically significant correlation found in the NF group was between PPT in the anterior tibial muscle and TSK-11 (r = -0.372; P < 0.01), while in the No-NF group it was between PPT in the suboccipital muscle and NDI (r = -0.288; P < 0.05). Statistically significant differences were found between the 2 CNSNP groups and CG in all cervical ROMs, but not between both CNSNP groups. The largest statistically significant correlation observed in the NF group was between cervical total rotation and TSK-11 (r = -0.473; P < 0.01), while in the No-NF group it was between cervical total latero-flexion and PCS (r = -0.532; P < 0.01). Although the S-LANSS scale has been validated as a screening tool for pain with NF, currently there is no "gold standard," so these findings should be interpreted with caution. Widespread pressure pain hyperalgesia was detected in patients with CNSNP with NF, but not in patients with CNSNP with No-NF. Patients with CNSNP presented bilateral pressure pain hyperalgesia over the cervical region and a decreased cervical ROM compared to healthy controls. However, no differences were found between the 2 CNSNP groups. These findings suggest differences in the mechanism of pain processing between patients with CNSNP with NF and No-NF.

No Differences Identified in Transverse Plane Biomechanics Between Medial Pivot and Rotating Platform Total Knee Implant Designs

BackgroundTotal knee arthroplasties (TKAs) using well-designed, fixed bearing prostheses, such as medial pivot (MP), have produced good long-term results. Rotating-platform, posterior-stabilized (RP-PS) mobile bearing implants were designed to decrease polyethylene wear. Sagittal and coronal plane TKA biomechanics are well examined and correlated to polyethylene wear. However, limited research findings describe this relationship in transverse plane. We assumed that although axial plane biomechanics might not be the most destructive parameters on polyethylene wear, it is important to clarify their role because both joint kinematics and kinetics in all 3 planes are important input parameters for TKA wear testing (International Organization for Standardization 14243-1 and 14343-3). Our hypothesis was that transverse plane overall range of motion (ROM) and/or peak moment show differences that reflect on wear advantages when compared RP-PS implants to MP designs. MethodsTwo groups (MPs = 24 and RP-PSs = 22 subjects) were examined by using 3D gait analysis. The variables were total internal-external rotation (IER) ROM and peak IER moments. ResultsNo statistically significant difference was demonstrated between the 2 groups in kinetics (P = .389) or kinematics (P = .275). ConclusionIn the present study, no wear advantages were found between 2 TKAs. Both designs showed identical kinetics at the transverse plane in level-ground walking. Kinematic analysis could not illustrate any statistically significant difference in terms of overall IER ROM. Nevertheless, kinematic gait pattern differences observed possibly reflect different patterns of joint surface motion or abnormal gait patterns. Thus, wear testing with various input waveforms combined with functional data analysis will be necessary to identify the actual effects of gait variability on polyethylene wear.

A New Methodology for Modeling and Free Vibrations Analysis of Rotating Shaft Based on the Timoshenko Beam Theory

The linear lateral free vibration analysis of the rotor is performed based on a new insight on the Timoshenko beam theory. Rotary inertia, gyroscopic effects, and shear deformations are included, but the torsion is neglected and a new dynamic model is presented. It is shown that if the total rotation angle of the beam cross section is considered as one of the degrees-of-freedom of the Timoshenko rotor, as is common in the literature, some terms are missing in the modeling of the global dynamics of the system. The total deflection of the beam cross section is divided into two steps, first the Euler angles relations are employed to establish the curved geometry of the beam due to the elastic deformation of the beam centerline and then the shear deformations was superposed on it. As a result of this methodology and the mutual interaction of shear and Euler angles some variable coefficient terms appeared in the kinetic energy of the system which makes the problem be classified as the parametrically excited systems. A linear coupled variable coefficient system of differential equations is derived while the variable coefficient terms have been missing in all previous studies in the literature. The free vibration behavior of parametrically excited system is investigated by perturbation method and compared with the common Rayleigh, Timoshenko, and higher-order shear deformable spinning beam models in the rotordynamics. The effects of rotating speed and slenderness ratio are studied on the forward and backward natural frequencies and the critical speeds of the system are examined. The study demonstrates that the shear and Euler angles interaction affects the high-frequency free vibrations behavior of the spinning beam especially for higher slenderness ratio and rotating speeds of the rotor.

The Different Methods of Displacement Monitoring at Loading Tests of Bridges or Different Structures

By measuring the displacements and deformations at different structures we deal in the Faculty of Civil Engineering, transportation Engineering and Architecture in University of Maribor for about 20 years. At that time we measured over 600 structures. Most loading tests of bridges and Viaducts were made. The measurements of movements needed to be as precise and accurate as possible. To do that laboratory test of instruments were made to see which instrument gives us reliable results. Displacements can be determined by geodetic and physical methods, depends of the construction. The use of geodetic methods are still preferable. In the paper the measurements with the total station, the level and rotation level, photogrammetry and solutions on the field by physical methods with inductive transducers are presented. We need to measure displacements as quick as possible but efficiently because we can not repeat the measurements under the same conditions. Also the surveying on the bridge and in the lab with the comparison of methods is presented under the different hard terrain conditions - water beneath the construction, big height of the structure, unapproachability, large span structures.

Functional Assessment of the Foot Undergoing Percutaneous Achilles Tenotomy in Term of Gait Analysis.

Background. This study was designed to evaluate the function of the foot undergoing the procedure of percutaneous Achilles tenotomy (PAT) in case of clubfoot management in terms of gait analysis. Methods. Nineteen patients with unilateral clubfeet were retrospectively reviewed from our database from July 2012 to June 2016. The result in all the cases was rated as excellent according to the scale of International Clubfoot Study Group (ICSG). The affected sides were taken as Group CF and the contralateral sides as Group CL. Three-dimensional gait analysis was applied for the functional evaluation of the involved foot. Results. Statistical difference was found in physical parameters of passive ankle dorsiflexion and plantar-flexion. No statistical difference was found in temporal-spatial parameters. There was statistical difference in kinematic parameters of total ankle rotation, ankle range of motion, and internal foot progression angle and in kinetic parameters of peak ankle power. No statistical difference was found in other kinematic and kinetic parameters. Conclusions. It is demonstrated that the procedure of PAT is safe and efficient for correcting the equinus deformity in case of clubfoot management and preserving the main function of Achilles tendon at the minimum of four-year follow-up.

The effect of dynamic stretching on hamstrings flexibility with respect to the spino-pelvic rhythm.

To ascertain the dynamic stretch effects of flexibility of the hamstrings on lumbar spine and pelvic kinematics. Tight hamstrings are positively correlated with low back pain. However, it is unclear how flexibility of the hamstrings affects spino-pelvic rhythm. Twelve healthy men participated in the study. The straight leg raising (SLR) angle, finger floor distance (FFD), and spino-pelvic rhythm was measured before and after the 6-week stretching protocol. The forward bending task was divided into 4 phases. The paired t-test was used to determine significant differences before and after the FFD, SLR angle, lumbar motion, and pelvic motion, and spino-pelvic rhythm in each phase (p<0.05). After 6 weeks of stretching, significant improvements were seen in the FFD with maximum forward bending and in the SLR angle. Total pelvic rotation was also significantly increased in contrast to total lumbar flexion. A decreased spino-pelvic ratio was seen in the final phase. Dynamic stretching could change the spino-pelvic rhythm to a pelvis-dominant motion, indicating that flexible hamstrings are important for preventing low back pain.

Sport Specific Adaptation in Rotation Range of Motion in the Elite Golfer’s Shoulder

Objective: Shoulder rotation in golfers is thought to determine the length of the back swing, which in turn influences club-head speed and ball drive distance. In athletes a decrease in shoulder internal rotation in the dominant shoulder when compared with the opposite side has been noted and is associated with increased risk of shoulder injury. It was hypothesised that golfers would bilaterally have more rotation range of motion compared to controls and that golfers would exhibit a unique pattern of rotation range of motion between their dominant and non-dominant/lead shoulders. The aim of the study was to compare rotation range of shoulder motion within and between male elite golfers and male non-athlete controls. Method: Forty five male golfers on European Challenge Tour and thirty six non-athlete control volunteers meet the inclusion criteria for the study. An inclinometer was used to determine the passive shoulder rotation range with the participant in supine. Results: Golfers’ shoulders have significantly more rotation range than controls in total arc of rotation (dominant side Δ15.30°, nondominant/lead side Δ21.98°, p=0.01) and in external rotation (dominant side Δ7.94°, non-dominant/lead side Δ11.04°, p=0.01). In golfers there are no differences in side to side comparison in: shoulder total arc of rotation (p=0.48), internal rotation (p=0.52), or in external rotation (p=0.54). Conclusion: Golfers’ shoulders have significantly more range than controls in total arc of rotation and in external rotation but the professional golfers in this study were not found to have a unique pattern of shoulder rotations between sides. This study endorses screening of shoulder rotation range in healthy elite professional golfers using side to side comparison. If unique loss of range is noted between sides in the context of a loss of total rotation range it may have consequences for the efficacy of the swing technique and potentially imply risk to injury