Plantar Flexion (plantar + flexion)

Distribution by Scientific Domains


Selected Abstracts


Lower leg muscle atrophy in ankle osteoarthritis

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2006
Victor Valderrabano
Abstract The aim of this study was to determine changes in the lower leg muscles associated with ankle osteoarthritis. Fifteen unilateral ankle osteoarthritis patients and fifteen age-gender-matched normal subjects were assessed with clinical [osteoarthritis latency time, pain, alignment, AOFAS ankle score, ankle range of motion (ROM), calf circumference], radiological (ankle osteoarthritis grading), and muscular-physiological parameters [isometric maximal voluntary ankle torque, surface electromyography of the anterior tibial (AT), medial gastrocnemius (MG), soleus (SO), and peroneus longus (PL) muscle]. The osteoarthritis patients had increased pain (6.8 points) and reduced AOFAS score (33.7 points) compared to the control group. Compared to the contralateral healthy leg, the arthritic leg showed reduced mean dorsi-/plantar flexion ROM (16.0), reduced mean calf circumference (2.1 cm), smaller mean dorsiflexion (16.4 Nm) and plantar flexion (15.8 Nm) torques, lower mean electromyography frequency for all muscles (AT ,22.6 Hz; MG ,27.3 Hz; SO ,25.9 Hz; PL ,28.5 Hz), and lower mean electromyography intensity in the AT [,28.0,,103 (v)2], MG [,13.3,,103 (v)2], and PL [,12.8,,103 (v)2]. SO mean electromyography intensity was not significantly changed [+2.0,,103 (v)2]. Unilateral ankle osteoarthritis is associated with atrophic changes of the lower leg muscles. This study supports previous observations on muscle dysfunction in knee osteoarthritis. 2006 Orthopaedic Research Society. 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source]


Effects of transient muscle contractions and stretching on the tendon structures in vivo

ACTA PHYSIOLOGICA, Issue 2 2002
K. KUBO
ABSTRACT This study compared the effects of static stretching (ST) and repeated muscle contractions (CON) on the viscoelastic properties of tendon structures in vivo. Eight male subjects performed ST (passively flexed to 35 of dorsiflexion) for 5 min and 50 repetitions of isometric maximum voluntary contraction (MVC) for 3 s each with 3 s relaxation. Before and after each task, the elongation of the tendon and aponeurosis of the medial gastrocnemius muscle (MG) was directly measured by ultrasonography, while the subjects performed ramp isometric plantar flexion up to MVC, followed by a ramp relaxation. The relationship between the estimated muscle force (Fm) and tendon elongation (L) during the ascending phase was applied to a linear regression, the slope of which was defined as stiffness of the tendon structures. The percentage of the area within the Fm,L loop to the area beneath the curve during the ascending phase was calculated as an index representing hysteresis. The ST protocol significantly decreased the stiffness (,8%) and hysteresis (29%)., respectively. In contrast, the CON protocol significantly decreased the stiffness, but not the hysteresis. These results suggested that the stretching and repeated contractions would make the tendon structures more complaint, and further decreased the hysteresis of the tendon structures. [source]


Undulating toe movements in brain death,

EUROPEAN JOURNAL OF NEUROLOGY, Issue 11 2004
G. Saposnik
For many years, death implied immobility. Nevertheless, there are anecdotal reports of spontaneous or reflex movements (SRMs) in patients with Brain death (BD). The presence of some movements can preclude the diagnosis of BD, and consequently, the possibility of organ donation for transplantation. McNair and Meador [(1992), Mov Dord7: 345,347] described the presence of undulating toe flexion movements (UTF) in BD patients. UTF consists in a sequential brief plantar flexion of the toes. Our aim was to determine the frequency, characteristics and predisposing factors of UTF movements in a prospective multicenter cohort study of patients with BD. Patients with confirmed diagnosis of BD were assessed to evaluate the presence of UTF using a standardized protocol. All patients had a routine laboratory evaluation, CT scan of the head, and EEG. Demographic, clinical, hemodynamic and blood gas concentration factors were analyzed. amongst 107 BD patients who fulfilled the AAN requirements, 47 patients (44%) had abnormal movements. UTF was observed in 25 (23%) being the most common movement (53%). Early evaluation (OR 4.3, CI95% 1.5,11.9) was a predictor of UTF in a multivariate regression model. The somato-sensory evoked potential (SSEPs) as well as brainstem auditory evoked potentials (BAEPs) did not elicit a cortical response in studied patients with UTF. This spinal reflex is probably integrated in the L5 and S1 segments of the spinal cord. Abnormal movements are common in BD, being present in more than 40% of individuals. UTF was the most common spinal reflex. In our sample, early evaluation was a predictor of UTF. Health care professionals, especially those involved in organ procurement for transplantation, must be aware of this sign. The presence of this motor phenomenon does not preclude the diagnosis of BD. [source]


Alteration of proton diffusivity associated with passive muscle extension and contraction

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2008
Masamitsu Hatakenaka MD
Abstract Purpose To determine whether passive muscle extension and contraction affect the proton diffusivity of the muscle. Materials and Methods Five male subjects were examined. The fractional anisotropy (FA), and primary (,1), secondary (,2), and tertiary eigenvalues (,3) of the right tibialis anterior and medial gastrocnemius muscles were compared between conditions of passive plantar flexion and passive dorsiflexion of the ankle joint. Results In the tibialis anterior, FA, and ,1 at dorsiflexion decreased significantly (P < 0.01 and P < 0.01, respectively) compared to those at plantar flexion, but ,3 at dorsiflexion increased significantly (P = 0.02). In the gastrocnemius, FA and ,1 at dorsiflexion increased significantly (P < 0.01 and P < 0.01, respectively) compared to those at plantar flexion, but ,3 at dorsiflexion decreased significantly (P < 0.01). The ,2 value showed no significant change in either the tibialis anterior or medial gastrocnemius. Conclusion The results indicate that passive muscle extension and contraction associated with passive joint movement would affect the proton diffusivity of the muscle. This alteration of proton diffusivity is probably associated with microscopic structural changes of the muscle. J. Magn. Reson. Imaging 2008;27:932,937. 2008 Wiley-Liss, Inc. [source]


Cadaveric flatfoot model: Ligament attenuation and Achilles tendon overpull

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2009
Andrew J. Blackman
Abstract Flatfoot deformity is characterized by loss of the medial longitudinal arch, forefoot abduction, hindfoot eversion, and often Achilles tendon contracture. Our objectives were to validate a cadaveric flatfoot model that involves selective ligament attenuation and to determine if Achilles tendon overpull is associated with increased pes planus severity. We measured the three-dimensional (3D) orientation of the bones of interest in the unloaded, loaded, and Achilles tendon overpull conditions. A flatfoot model was created by attenuating ligaments involved in the pes planus deformity followed by cyclic axial loading, and bone orientations were acquired in the three conditions. Significant differences seen between normal feet and flat feet were consistent with those seen with the pes planus deformity. The first metatarsal dorsiflexed and abducted relative to the talus. The navicular abducted relative to the talus. The calcaneus everted relative to the tibia. The talus plantar flexed and adducted. Achilles overpull resulted in first metatarsal-to-talus dorsiflexion and navicular-to-talus abduction. Thus, selective ligament attenuation followed by cyclic axial loading can create a cadaveric flatfoot model consistent with the in vivo deformity. Longitudinal arch depression, hindfoot eversion, talonavicular joint abduction, forefoot abduction, and talar plantar flexion were seen. Simulated Achilles tendon contracture increased the severity of the deformity, particularly in arch depression and forefoot abduction. 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1547,1554, 2009 [source]


Lower leg muscle atrophy in ankle osteoarthritis

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2006
Victor Valderrabano
Abstract The aim of this study was to determine changes in the lower leg muscles associated with ankle osteoarthritis. Fifteen unilateral ankle osteoarthritis patients and fifteen age-gender-matched normal subjects were assessed with clinical [osteoarthritis latency time, pain, alignment, AOFAS ankle score, ankle range of motion (ROM), calf circumference], radiological (ankle osteoarthritis grading), and muscular-physiological parameters [isometric maximal voluntary ankle torque, surface electromyography of the anterior tibial (AT), medial gastrocnemius (MG), soleus (SO), and peroneus longus (PL) muscle]. The osteoarthritis patients had increased pain (6.8 points) and reduced AOFAS score (33.7 points) compared to the control group. Compared to the contralateral healthy leg, the arthritic leg showed reduced mean dorsi-/plantar flexion ROM (16.0), reduced mean calf circumference (2.1 cm), smaller mean dorsiflexion (16.4 Nm) and plantar flexion (15.8 Nm) torques, lower mean electromyography frequency for all muscles (AT ,22.6 Hz; MG ,27.3 Hz; SO ,25.9 Hz; PL ,28.5 Hz), and lower mean electromyography intensity in the AT [,28.0,,103 (v)2], MG [,13.3,,103 (v)2], and PL [,12.8,,103 (v)2]. SO mean electromyography intensity was not significantly changed [+2.0,,103 (v)2]. Unilateral ankle osteoarthritis is associated with atrophic changes of the lower leg muscles. This study supports previous observations on muscle dysfunction in knee osteoarthritis. 2006 Orthopaedic Research Society. 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source]


Comparison of oxidative capacity among leg muscles in humans using gated 31P 2-D chemical shift imaging

NMR IN BIOMEDICINE, Issue 10 2009
Sean C. Forbes
Abstract In many small animals there are distinct differences in fiber-type composition among limb muscles, and these differences typically correspond to marked disparities in the oxidative capacities. However, whether there are similar differences in the oxidative capacity among leg muscles in humans is less clear. The purpose of this study was to compare the rate of phosphocreatine (PCr) recovery, a functional in vivo marker of oxidative capacity, in the lateral and medial gastrocnemius, soleus, and the anterior compartment of the leg (primarily the tibialis anterior) of humans. Subjects performed plantar flexion and dorsiflexion gated exercise protocols consisting of 70 sets of three rapid dynamic contractions (<2.86,s) at 20,s intervals (total: 23.3,min). Starting after the sixth set of contractions, 31P 2-D CSI (8,,8 matrix, 14,16,cm FOV, 3,cm slice, TR 2.86,s) were acquired via a linear transmit/receive surface coil using a GE 3T Excite System. The CSI data were zero-filled (32,,32) and a single FID was produced for each time point in the lateral and medial gastrocnemius, soleus, and anterior compartment. The time constant for PCr recovery was calculated from ,,=,-,t/ln[D/(D,+,Q)], where Q is the percentage change in PCr due to contraction during the steady-state portion of the protocol, D the additional drop in PCr from rest, and ,t is the interval between contractions. The , of PCr recovery was longer (p,<,0.05) in the anterior compartment (32,,3,s) than in the lateral (23,,2,s) and medial gastrocnemius muscles (24,,3,s) and the soleus (22,,3,s) muscles. These findings suggest that the oxidative capacity is lower in the anterior compartment than in the triceps surae muscles and is consistent with the notion that fiber-type phenotypes vary among the leg muscles of humans. Copyright 2009 John Wiley & Sons, Ltd. [source]


The effects of Masai Barefoot Technology, footwear on posture: an experimental designed study

PHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 4 2007
Paul New
Introduction.,This study was approved by the University of Southampton Ethics Committee. The aim of the study was to assess the anatomical changes to upright posture that occur in the sagittal plane as a result of wearing Masai Barefoot Technology (MBT) footwear during standing and walking. MBT claims that its innovative unstable shoes promote a more upright posture in which musculature is strengthened and joint wear reduced (Amann and Amann, 2004). This could be helpful in the management and prevention of conditions such as osteoarthritis and back pain. Method.,Twelve students (six male and six female), aged between 18 and 40 years, at the University of Southampton participated in the study. Participants attended one session at a biomechanics laboratory. The kinematics of posture while wearing MBT shoes during standing and gait were examined, using a two-dimensional motion analysis system, and compared to a control shoe. Statistical significance was tested by use of a paired t -test and a Wilcoxon signed-ranks test. Results.,Students standing in MBT footwear demonstrated a statistically significant increase in plantar flexion at the ankle joint (p = 0.025; mean flexion 3.02; 95% confidence interval [95% CI] ,5.6 to ,0.4). Walking in MBT shoes showed a decrease in trunk flexion (p = 0.007; mean flexion 1.44; 95% CI ,2.4 to ,0.4) and a reduction in anterior tilt of the pelvis (p = 0.003; mean tilt 3.20; 95% CI ,5.06 to ,1.35) at heel strike. At toe-off a significant reduction in anterior pelvic tilt (p = 0.035; mean tilt 2.35; 95% CI) was found in the MBT shoes. There was no significant difference found between the two shoe conditions at mid-stance, pelvic tilt (p = 0.53; mean tilt 1.83 degrees) trunk flexion (p = 0.05; mean flexion 0.95 deg). Conclusion.,MBT footwear changes certain characteristics of posture in quiet standing and walking. These findings could have positive implications for the management of conditions such as osteoarthritis and back pain; however, further research is needed. Copyright 2007 John Wiley & Sons, Ltd. [source]