Active Ankle Dorsiflexion Research Articles

Functional Connectivity Between Secondary and Primary Motor Areas Underlying Hand–Foot Coordination

Coincident hand and foot movements are more reliably performed in the same direction than in opposite directions. Using transcranial magnetic stimulation (TMS) to assess motor cortex function, we examined the physiological basis of these movements across three novel experiments. Experiment 1 demonstrated that upper limb corticomotor excitability changed in a way that facilitated isodirectional movements of the hand and foot, during phasic and isometric muscle activation conditions. Experiment 2 demonstrated that motor cortex inhibition was modified with active, but not passive, foot movement in a manner that facilitated hand movement in the direction of foot movement. Together, these findings demonstrate that the coupling between motor representations within motor cortex is activity dependent. Because there are no known connections between hand and foot areas within primary motor cortex, experiment 3 used a dual-coil paired-pulse TMS protocol to examine functional connectivity between secondary and primary motor areas during active ankle dorsiflexion and plantarflexion. Dorsal premotor cortex (PMd) and supplementary motor area (SMA) conditioning, but not ventral premotor cortex (PMv) conditioning, produced distinct phases of task-dependent modulation of excitability of forearm representations within primary motor cortex (M1). Networks involving PMd-M1 facilitate isodirectional movements of hand and foot, whereas networks involving SMA-M1 facilitate corticomotor pathways nonspecifically, which may help to stabilize posture during interlimb coordination. These results may have implications for targeted neurorehabilitation after stroke.

Treatment of equinus deformity with Ilizarov fixator

目的 探讨应用Ilizarov外固定支架治疗创伤性马蹄足的疗效.方法2003年2月～2005年8月应用Ilizarov外固定架治疗17例创伤所致马蹄足患者.将组装好的Ilizarov外固定架按照Ilizarov的穿针固定原则安装在患侧小腿和足部.术后3 d开始转动螺纹杆上的螺母,第1周旋转螺母2～4圈/d,4次/d;1周后旋转螺母1～2圈/d,4次/d,分别逐渐缩短和延长前、后螺纹杆,矫正马蹄足畸形.用伊氏架将踝关节固定在中立位2～3个月.去除外固定架后让患者逐渐增加负重量直至完全负重.不负重时穿戴支具保持踝关节处于中立位至少3个月.结果17例患者均得到随访,平均随访10个月(7～14个月).术后4～6周踝关节恢复到中立位.平均带外固定架14.5周(10～16周).无血管、神经损伤.3例各1处针道轻度感染,对症处理后感染消失.1例诉矫正过程中疼痛,术后10周去除外固定架,去除外固定架后6周时僵直在跖屈20°.1例去除外固定架4个月后僵直在跖屈10°.1例小腿前后肌群损伤严重合并胫骨骨缺损重建术后踝关节矫正到中立位后1.5个月行踝关节融合术,融合术后3个月去除外固定架.其余14例达到0°全足负重,行走时无明显足下垂.2例负重时疼痛.踝关节背伸肌群功能存在的患者,踝关节可主动背伸10°.结论Ilizarov外固定架是治疗创伤性马蹄足的微创技术。

The Acute Effects of Static Stretching on Human Hopping Performance

Static stretching is related to increases in joint range of motion (ROM), however, the relationship between stretching and movement performance is unclear. Some suggest an acute bout of stretching enhances neuromuscular performance, whereas other evidence points to a detrimental effect. PURPOSE: To determine the acute effects of static stretching on performance measurements of a bouncing gait represented by bipedal hopping. METHODS: Participants were randomly assigned to either a control (C) or static stretching (EXP) group (n=12 each group). Plantar-flexor muscle activity, active ankle joint stiffness (kA), and leg stiffness (kL) were measured during preferred-height hopping. These variables were calculated for the lowering phase of ground contact, from initial contact to the lowest vertical position of the center of mass (COM). Muscle activity was measured with surface electromyographic (EMG) electrodes over the gastrocnemius (lateral and medial) and soleus muscles. Active kA was calculated as the ratio of net muscle torque to ankle angular displacement and kL was calculated as the ratio of change in vertical GRF to vertical displacement of the COM. Hopping frequency was maintained at 2.2 Hz with the aid of a metronome. In addition, measurements of active ankle dorsiflexion ROM were recorded before each trial of hopping. Participants performed two trials of 60-s hopping. Between trials the EXP group participated in static stretching of the plantar-flexor muscles and C group rested. Comparison of the change in hopping variables from one trial to the next was made between groups using a one-way MANO VA and comparison of change in active ROM between groups was made with a one-way ANOVA. RESULTS: Univariate examination of changes in active dorsiflexion ROM between the C and EXP groups demonstrated a difference (AROM: 0.0(1.1) vs. 1.6(2.0) degrees, p=0.02). Multivariate examination of the changes in hopping variables from one trial to the next showed no difference between groups (muscle activity ratio: 0.9(0.2) vs. 1.0(0.2) IEMG post/pre, δkA: 8(50) vs. 20(32) Nm rad−1, δkL 0.3(1.9) vs. 0.1(1.2) kN m−1, p=0.46). All data are presented as mean (SD), C and EXP respectively. CONCLUSIONS: The observed increase in ankle dorsiflexion ROM after static stretching is in agreement with previous findings. There is, however, no support for either an enhancing or detrimental effect of static stretching on performance measures during bipedal hopping.

Confiabilidade de dois métodos de avaliação da amplitude de movimento ativa de dorsiflexão do tornozelo em indivíduos saudáveis

A medida da amplitude do movimento é um importante parâmetro utilizado na avaliação e no acompanhamento fisioterápico. Portanto, a confiabilidade destas medidas e dos instrumentos utilizados para esta finalidade deve ser avaliada. Objetivo: Avaliar e comparar a confiabilidade intra-examinador e interexaminador da medida de amplitude do movimento (ADM) de dorsiflexão ativa do tornozelo utilizando um goniômetro universal e um inclinômetro digital. Métodos: Dois estudantes avaliaram a amplitude de dorsiflexão de 28 voluntários com idade entre 18 e 30 anos utilizando um inclinômetro digital e um goniômetro universal. Resultados: Os resultados demonstram média e desvio padrão da amplitude do movimento de 18,1±3,1 e 18,6±3,8 graus para as medidas obtidas pelo goniômetro e inclinômetro, respectivamente. O coeficiente de correlação intraclasse (CCI) encontrado para a condição na mesma sessão para as medidas obtidas com o inclinômetro foi de 0.91 e 0.83, para os examinadores A e B, respectivamente. Já o CCI obtido pelo goniômetro foi de 0.91 e 0.97 para os examinadores A e B, respectivamente. Os resultados da confiabilidade entre as sessões de teste demonstraram confiabilidade moderada para as medidas de goniometria e alta confiabilidade para a inclinometria. Já a confiabilidade interexaminador foi moderada para as medidas obtidas pelo goniômetro e alta para as medidas obtidas pelo inclinômetro. Conclusão: Os resultados do presente estudo demonstraram uma maior confiabilidade para as medidas de amplitude de movimento obtidas pelo inclinômetro digital quando comparado com o goniômetro universal, principalmente quando a confiabilidade interexaminador foi avaliada.

Intrinsic Factors Associated With Exercise-Related Leg Pain in Collegiate Cross-Country Runners

This study (1) examined the occurrence of exercise-related leg pain (ERLP) in collegiate cross-country athletes and (2) compared structural factors in runners with and without ERLP history. Cross-sectional design comparing 2 groups of cross-country athletes (with and without ERLP history). Intercollegiate athletics. A total of 63 athletes (30 males, 33 females) representing 2 cross-country teams consented to participate. Athlete examination included self-report of ERLP history, active ankle dorsiflexion with knee extended and flexed, navicular drop (ND), and 1st ray length. ND index was calculated by dividing ND by 1st ray length. Athletes on 1 team (n = 32) were followed through 1 season to identify incidence of ERLP over the course of 1 season. Independent t tests were used to compare structural measures of those with and without ERLP history, and chi2 was used to examine frequencies. Of the 63 athletes, 33 (52%) reported ERLP history; most reported medial leg pain and also bilateral symptoms. No differences in structural measures were found between those with and without ERLP history. Ten of 32 athletes (31%) reported the occurrence of ERLP during the fall season, 8 of whom had a history of ERLP. Exercise-related leg pain was a common complaint among these athletes, usually occurring bilaterally and located along the medial leg. Athletes with ERLP history did not have a greater foot pronation as measured by ND, nor was there limited ankle range of motion as compared with those without ERLP history. Further research is needed to identify factors associated with the development of ERLP.

Variability and predictability of functional efficacy of botulinum toxin injection in leg spastic muscles

Botulinum toxin injection reduces spasticity level. However, the effects on gait parameters and daily living activities remain controversial, and the prediction of results remains poorly evaluated. The aim of this open study was to investigate these effects, and the predictability of results. Forty-seven injections were given to 47 patients with stroke (males: 24; mean age: 51.7), in the soleus, gastrocnemius, tibialis posterior and anterior, and flexor digitorum longus, with a global dose of 300 U (Botox®). Each was evaluated at day 1 (D1), day 15 (D15), month 2 (M2) and month 5 (M5). We observed a significant but moderate reduction in spasticity (Ashworth) of the ankle plantar flexors (0.72/5) and dorsiflexors, which was greater at D15, and an improvement in distal positioning in the upright situation. Upright balance and gait (Functional Ambulation Categories) were improved, especially at M2 and in the barefoot condition. Gait velocity and step length with usual aids (10 m) were discretely increased, and this was especially evident in about 15 patients. We also found improvement in the Rivermead Motor Assessment. Patients reported better foot positioning, facilitation in limb propulsion, and better static and dynamic balance. For each assessment, high variability in the effects was also shown. Improvement in functional tests was partially predicted by age (negative relation), delay since stroke (negative relation), gender (better in men), spasticity of hip adductors and knee extensors (negative relation), active ankle dorsiflexion (positive relation) and heel–ground distance (positive relation). In conclusion, the effects on spasticity, balance and gait were relatively modest, and with a large variability between patients. Functional improvement could be partially predicted by several general or specific factors, the knowledge of which is important in the selection of patients to be injected, and for future trials aiming to demonstrate the efficacy of botulinum toxin injection.

Effect of Sensory-Level Electrical Stimulation of the Tibialis Anterior Muscle During Physical Therapy on Active Dorsiflexion of the Ankle of Children with Cerebral Palsy

The aim of the study was to determine whether add-on electrical stimulation (ES) at the sensory level improves ankle dorsiflexion in children with cerebral palsy. Seventeen children (three to nine years of age) with spastic hemiplegia or diplegia with weak or absent active ankle dorsiflexion received ES therapy applied to the tibialis anterior muscle during ordinary scheduled physical therapy sessions for one month. The ES was given at the sensory level alone with the aim of increasing the child's sensory awareness of the voluntary movement of the ankle. Statistically significant improvement occurred in active ankle dorsiflexion with the knee flexed and extended between the first (pre) test and the subsequent tests (zero, two, and nine months later). Active toe flexion and extension and active inversion and eversion of the feet improved significantly. ES at the sensory level combined with physical therapy improves active and passive motion of the ankle and foot that persists months after stimulation component is removed.

Evaluation of triceps surae muscle length and resistance to passive lengthening in patients with acquired brain injury

Objective. To examine changes in muscle length and resistance to passive lengthening in the triceps surae muscles in patients with recently acquired brain injury. Background. Increased passive resistance in the triceps surae muscles is common following acquired brain injury. Adaptive shortening secondary to relative immobility, and increased stiffness due to rheologic changes within the musculo-tendinous unit, may be exacerbated by plantarflexor muscle overactivity related to the brain injury itself. Design. Three variables representing resistance to passive lengthening and soleus muscle length were compared between subjects with recent brain injury and age matched normal controls. Comparison between limbs was made for subjects with unilateral neurological impairment. Methods. Slow passive dorsiflexion stretches were performed using a computer controlled dynamometer. Muscle stiffness in the initial and latter portion of the range, and the angles achieved at torques of 5 and 10 N m were determined from torque–angle curves. Maximal ankle dorsiflexion with the knee flexed was considered to reflect soleus muscle length. Results. Significant differences were demonstrated for all variables, except passive stiffness near the end of available range. The limb ipsilateral to unilateral brain injury differed from control limbs in that significantly less passive range of dorsiflexion was available and initial resistance to passive stretch was significantly less. Conclusions. The reduction in soleus muscle length evident in subjects with recent acquired brain injury, even in neurologically unaffected limbs, may reflect the influence of relative immobility. Although plantarflexor muscle overactivity was found to be associated with increased resistance to slow passive stretch, the mechanism was unable to be elucidated from these data. The limb ipsilateral to unilateral neurological impairment cannot be considered to be a `normal' control for comparative purposes. Relevance Adaptive shortening and increased resistance to passive lengthening limit active ankle dorsiflexion, and alter ankle biomechanics. Tonic muscle overactivity has the potential to exacerbate these changes. Prophylactic management of inappropriate muscle activity and maintenance of muscle length may facilitate the achievement of rehabilitation goals and reduce subsequent disability following acquired brain injury.

A method for evaluating the results of tendon transfers for foot drop.

A system for assessing the results of tibialis posterior tendon transfers in the treatment of foot drop secondary to nerve palsy is proposed. There are seven sections to this scoring system: pain, need for orthosis, ability to wear normal shoes, activity level, muscle power of ankle dorsiflexion, degree of active ankle dorsiflexion, and foot posture. The total score is 100. The results are classified as excellent for scores between 85 and 100, good between 70 and 84, fair between 55 and 69, and poor for scores below 55. The results of 18 patients (mean followup, 64.6 months) who had a tibialis posterior tendon transfer were assessed using this method. Four patients (22.2%) had an excellent result, seven (38.8%) had a good result, two (11.1%) had a fair result, and five (27.7%) had a poor result. The average score was 67.2, suggesting an overall fair result for this operation. In nine patients, there was correlation between the outcome when assessed with this method and with patient rating. In two patients, the outcomes were better when assessed with this method than with patient rating, whereas the reverse was true in seven other patients. Thus, this system may provide a more objective and critical evaluation of tibialis posterior transfers for foot drop.

Posterior tibial tendon transfer for drop-foot. 20 cases followed for 1-5 years.

From 1991 to 1997 we performed 20 tibialis posterior tendon-transfer operations in 17 patients with drop-foot, in 11 of peripheral neurogenic origin and in 6 because of neuromuscular disease. Postoperatively, all patients could walk without an ankle-foot orthosis. At follow-up after mean 2 (1-5) years, all patients had active dorsiflexion of the foot and toes, with a median active ankle dorsiflexion of 5 degrees (-15-10 degrees). The median active plantar flexion was 40 degrees (10-45 degrees), and the total range of movement was 40 degrees (15-50 degrees). At follow-up, the gait was good in 15 and improved in 2 of the 17 patients.

Effect of subject position on the reliability of measurement of active ankle joint dorsiflexion

The aim of this study was to compare the intratester reliability of goniometry for measurements of active ankle joint dorsiflexion (AJDF) using three subject positions. These positions were supine, prone (knee extended) and sitting (knee flexed). Twenty-six healthy subjects (mean age 42.3 years) were measured on two separate occasions (mean interval 7.85 days). The prone position produced the lowest measurements (mean 6.5°, SD 4.6°) and the sitting position produced the greatest measurements (mean 11.7°, SD 6.0°). An ANOVA two-factor within subjects was undertaken to test the hypothesis that there was no significant difference in the reliability of the three positions to measure AJDF ( P<0.05). A post hoc test concluded that there were significant differences between prone and sitting ( P<0.05) and supine and sitting positions ( P<0.05), but no significant difference between prone and supine positions. Analysis using Intraclass Correlation Coefficient (ICC) demonstrated consistent intratester measurements (0.936) between the two occasions.

Significance of the confusion test in cerebral palsy.

The confusion test examines ankle dorsiflexion in patients with cerebral palsy. Orthopedists have related this test to swing-phase activity of the tibialis anterior, and have used it as a prerequisite for tendon transfer. To determine the validity of this assumption, ankle dorsiflexion was tested in 47 normal children. Forty-seven percent had a positive, unresisted confusion test, and 97% had a positive, resisted confusion test. Twenty-three patients with cerebral palsy who had a positive confusion test underwent gait analysis. Tibialis anterior electromyographs showed wide variability. Sagittal-plane ankle-movement curves revealed five patterns. Thirty-three percent of the patients showed abnormal swing-phase dorsiflexion, and 61% had abnormal swing-phase plantar-flexion. We conclude that the confusion test evaluates a normal, patterned response, and is positive in most children with cerebral palsy. Although a positive confusion test shows that active ankle dorsiflexion is possible, it is not predictive of swing-phase ankle kinematics.

The Changes in Intramuscular Pressure and Femoral Vein Flow With Continuous Passive Motion, Pneumatic Compressive Stockings, and Leg Manipulations

Intramuscular pressure was measured continuously in the deep compartment of the calf and anterior thigh of volunteers while their legs were cyclically moved from 0 degrees to 90 degrees back to 0 degrees (angle of knee flexion) in an anatomic continuous passive motion (CPM) device and a nonanatomic CPM device. Femoral venous flow was measured continuously using a thermodilution technique in volunteers while their legs were moved in both CPM devices, during inflation of a pneumatic stocking, and during several leg manipulations. Baseline intramuscular pressures in the deep calf and anterior thigh were 10.0 +/- 1.9 mmHg and 4.9 +/- 1.9 mmHg, respectively (mean +/- standard error). Both the anatomic and nonanatomic CPM devices produced a statistically significant maximal increase in pressure in the calf. By contrast, only a decrease in pressure occurred in the thigh with both devices. Baseline femoral vein flow measured by the thermodilution technique was 311 +/- 38 ml per minute. Significant increases in femoral vein flow were seen with both CPM devices. The maximal flow produced by the anatomic CPM was 1199 ml per minute and was approximately four times higher than baseline flow and approximately 1.4 times the maximal flow change seen with the nonanatomic CPM (836 ml per minute). The greatest net increase in flow was observed between 60 degrees and 90 degrees of knee flexion with both devices. Overall, passive straight-leg elevation produced the largest flow (1524 ml per minute), followed by the anatomic CPM and nonanatomic CPM, and then by active ankle dorsiflexion(640 ml per minute), pneumatic stocking inflation (586 ml per minute), manual calf compression (532 ml per minute), and passive dorsiflexion (385 ml per minute)(ABSTRACT TRUNCATED AT 250 WORDS)

Reciprocal inhibition upon initiation of voluntary movement

Phasic changes in reciprocal inhibition of the soleus motoneurons upon initiation of active ankle dorsiflexion was investigated in normal man. H-reflex and reaction time methods were combined. Two phases of reciprocal inhibition were observed. The first inhibition appeared almost simultaneously with the activity of agonist EMG but was so weak as to be cancelled with a strong test stimulus or a slight stretch of the test muscle. The second inhibition developed 100 ms after EMG onset, in the early stage of dynamic contraction, and was strong. These inhibitions increased as the voluntary effort was strengthened. The neural mechanism of these inhibitions is discussed.

Kinaesthetic role of muscle afferents in man, studied by tendon vibration and microneurography.

The characteristics of vibration-induced illusory joint movements were studied in healthy human subjects. Unseen by the subject, constant frequency vibration trains applied to the distal tendon of the Triceps or Biceps induced an almost constant velocity illusory movement of the elbow whose direction corresponded to that of a joint rotation stretching the vibrated muscle. Vibration trains of the same duration and frequency applied alternatively to the Biceps and Triceps evoked alternating flexion-extension illusory movements. During successive application of vibration trains at frequencies from 10 to 120 Hz, the perceived velocity of the illustory movements increased progressively from 10 to 70-80 Hz, then decreased from 80 to 120 Hz. The maximal perceived velocity was three times higher during alternating vibration of the Biceps and Triceps than during single muscle stimulation. Unit activity from 15 muscle spindle primary endings and five secondary endings located in Tibialis anterior and Extensor digitorum longus muscles were recorded using microneurography in order to study their responses to tendon vibration and passive and active movements of the ankle. Primary endings were all activated by low amplitude tendon vibration (0.2-0.5 mm) previously used to induce illusory movements of the elbow. The discharge of some was phase-locked with the vibration cycle up to 120 Hz, while others responded one-to-one to the vibration cycle up to 30-50 Hz, then fired in a sub-harmonic manner at higher frequencies. Secondary endings were much less sensitive to low amplitude tendon vibration. Primary and secondary ending responses to ramp and sinusoidal movements of the ankle joint were compared. During the movement, the primary ending discharge frequency was almost constant, while the secondary ending activity progressively increased. During ankle movements the primary ending discharge appeared mainly related to velocity, while some secondary activities seemed related to both movement velocity and joint angle position. Muscle spindle sensory ending responses to active and passive ankle movements stretching the receptor-bearing muscle (plantar flexion) were qualitatively and quantitatively similar. During passive reverse movements (dorsiflexion) most of the sensory endings stopped firing when their muscle shortened. Active muscle shortening (isotonic contraction) modulated differently the muscle spindle sensory ending discharge, which could stop completely, decrease or some times increase during active ankle dorsiflexion. During isometric contraction most of the muscle spindle sensory endings were activated. The characteristics of the vibration-induced illusory movements and the muscle spindle responses to tendon vibration and to active and passive joint movements strengthened the possibility of the contribution of primary endings to kinesthesia, as suggested by several previous works...