Flexibilidad de miembros inferiores y fuerza abdominal en futbolistas juveniles mediante aplicación del método pilates

Objetivo. Comparar el efecto del método Pilates con un método tradicional sobre la fuerza resistencia abdominal y la flexibilidad de los miembros inferiores en futbolistas de categoría juvenil en Cali. Metodología. La investigación se abordó desde el enfoque empírico-analítico con un diseño cuasi experimental. Para ello, se realizó pretest- intervención y postest en dos grupos, un grupo experimental y un grupo control con 40 futbolistas de la categoría juvenil de dos escuelas de fútbol de Cali, Colombia, que cumplieron con los criterios de inclusión. Resultados. Se encontraron diferencias estadísticamente significativas con el método Pilates al momento de valorar la flexibilidad de los deportistas, en la articulación de tobillo derecho en dorsiflexion (p- 0,00), en las articulaciones de las rodillas derecha e izquierda en flexión (p= 0,00), en las articulaciones de caderas derecha e izquierda para extensión y flexión (p= 0,00), en la articulaciones del tronco en flexión y extensión (p= 0,00; p- 0,02), al igual que flexión lateral derecha e izquierda (p= 0,01) y en fuerza abdominal (p= 0,00). Discusión y conclusiones. Si bien la utilización del método tradicional refleja un aumento en las medias de las variables estudiadas, dicho aumento no es estadísticamente significativo. Por el contrario, con la utilización del método Pilates como entrenamiento de la flexibilidad de miembros inferiores y fuerza muscular (abdominal) en jóvenes futbolistas se demuestra un importante aumento en las medias, evidenciando diferencias estadísticamente significativas.

Objective. To compare the effect of the Pilates method with a traditional method on abdominal resistance strength and lower limb flexibility in young soccer players from Cali. Materials and methods. The research was conducted from the empirical-analytical approach with a quasi-experimental design. For this, pre-test, intervention, and post-test were carried out in two groups, experimental and control, with 40 youth category soccer players from two soccer schools in Cali (Colombia) who met the inclusion criteria. Results: Statistically significant differences were found with the Pilates method when assessing the flexibility of the athletes in the right ankle joint in dorsiflexion (p = 0.00), the right and left knee joint in flexion (p = 0.00), the right and left hip joint in extension and flexion (p = 0.00), the trunk joint in flexion and extension (p = 0.00; p = 0.02), right and left lateral flexion (p = 0.01), and abdominal strength (p = 0.00). Discussion and Conclusions: While the traditional method reflects an increase in the means of the variables studied, this increase is not statistically significant. On the contrary, the Pilates method to train young soccer players' lower limb flexibility and muscular strength (abdominal) demonstrated a significant increase in means, with statistically significant differences.

Definition of Spasticity / The Japanese Journal of Rehabilitation Medicine

<p>Although the term “spasticity” refers to one of the most important concepts in physical medicine and rehabilitation, it is inconsistently defined, particularly in the Japanese literature.<br/>Here, I have presented several definitions widely used throughout Japan and discussed differences among those proposed by Lance, Shimamura, and Tanaka. The use of the phrase “phasic and tonic stretch reflexes” and the meaning of “rigidity” were indicated to cause confusion regarding the definition.<br/>Exaggerated tendon jerks without a reflex response during a continuous muscle stretch should not be included under spasticity. However, if tendon jerks are exaggerated, the increased stretch reflexes without muscle (or joint) movement should be termed “spasticity” rather than “rigidity.” Although some researchers use the term “rigidospasticity” to express severe spasticity, it differs from the original meaning.<br/>According to the discussion, I agree with the definition proposed by Lance：“Spasticity is a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex, as one component of the upper motor neuron syndrome.” However, it is a mysterious phenomenon that depends not only on velocity but also on muscle length. Further review of its definition is required.</p>

Protective effects of pulmonary stretch reflex on the lung injury in rabbits with acute respiratory distress syndrome / 中华急诊医学杂志

Objective To evaluate the effect of the pulmonary stretch reflex on the lung injury in acute respiratory distress syndrome (ARDS). Method ARDS models of rabbits were induced by intratracheal infusion hydrochloric acid and ventilated with neurally adjusted ventilatory assist (NAVA) with a tidal volume ( VT) of 6 mL/kg and the electrical activity of diaphragm ( Eadi)-determined PEEP level. The rabbits were randomly ( random number) divided into two groups: ( 1 ) sham operation (Sham) group ( n = 5 ),(2) bilateral vagotom (VAG) group( n = 5 ). Gas exchange and pulmonary mechanics were determined at baseline, after lung injury and ventilation 1, 2, 3 h respectively. Indices about pulmonary permeability,pathological changes and inflammatory response were also measured. Results Compared with Sham group,the PaO2/FiO2in VAG group decreased significantly at ventilation 2 h, 3 h (P ＜0.05). There was no significant difference on PaCO2 between Sham and VAG group (P ＞ 0.05 ), and VAG group had the higher VT,peak pressure ( Ppeak), mean pressure (Pm) compared with Sham group at the time point of ventilation 1 h, 2 h, 3 h (P＜0.05). Compared with Sham group, the dead space fraction (VD/VT) and the respiratory system elastance (Ers) in VAG group increased (P ＜ 0.05 ) and the static pulmonary compliance (Cst)decreased markedly (P ＜ 0.05 ) after 3 h ventilation. The wet/dry weight (W/D), lung injury score, tumor necrosis factor-α ( TNF-α), interleukin-8 ( IL-8 ), myeloperoxidase ( M PO ) and malondialdehyde ( M DA )in VAG group elevated significantly when compared with Sham group ( P ＜ 0.05 ). Conclusions The lung injury in ARDS was aggravated after bilateral vagotomy, which demonstrated that the pulmonary stretch reflex may have the lung protective effect.

Effects of pulmonary stretch reflex on lung injury in rabbits with acute respiratory distress syndrome / 世界急诊医学杂志（英文）

BACKGROUND: Pulmonary stretch reflex plays an important role in regulation of respiratory movement. This study aimed to evaluate the effect of pulmonary stretch reflex on lung injury in rabbits with acute respiratory distress syndrome (ARDS). METHODS: ARDS rabbits were given intratracheal infusion of hydrochloric acid and ventilated with neurally adjusted ventilatory assistance (NAVA) with a tidal volume (VT) of 6 mL/kg and the electrical activity of diaphragm (EAdi)-determined positive end expiratory pressure. After isolation of the bilateral vagusnerve trunk, the rabbits were randomized into two groups: sham operation (SHAM) group (n=5) and bilateral vagotomy (VAG) group (n=5). Gas exchange and respiratory mechanics were detected at baseline, after lung injury and 1, 2, and 3 hours after ventilation respectively. Pulmonary permeability index, pathological changes and inflammatory response were also measured. RESULTS: Compared with the SHAM group, PaO2/FiO2 in the VAG group decreased significantly 2 and 3 hours after ventilation (P<0.05). There was no significant difference in PaCO2 between the SHAM and VAG groups (P>0.05), and the VAG group had a high VT, peak pressure (Ppeak), and mean pressure (Pm) compared with the SHAM group 1, 2, 3 hours after ventilation (P<0.05). Compared to the SHAM group, dead space fraction (VD/VT) and respiratory system elastance (Ers) in the VAG group increased (P<0.05) and static pulmonary compliance (Cst) decreased markedly (P<0.05) after ventilation for 3 hours. Lung wet/dry weight ratio (W/D) (8.4±1.2 vs. 6.6±1.0), lung injury score (6.3±1.8 vs. 3.8±1.3), tumor necrosis factor-α (TNF-α) (779±372 pg/mL vs. 355±130 pg/mL) and interleukin-8 (IL-8) (169±21 pg/mL vs. 118±17 pg/mL) increased significantly in the VAG group compared with the SHAM group (P<0.05). CONCLUSION: Lung injury is aggravated after bilateral vagotomy, demonstrating that pulmonary stretch reflex may have protective effect on the lung.

Evaluation of Elbow Stretch Reflex Using a Portable Hand-driven Isokinetic System in Normal Adults

OBJECTIVE: To evaluate normal healthy persons without spasticity to observe normal findings of the elbow stretch reflex using a newly developed, portable, hand-driven spasticity-measuring system. METHOD: Thirty normal persons without any disease involving the central or peripheral nervous system were enrolled in this study. The portable hand-driven isokinetic system is able to measure the joint angle, angular velocity, electromyographic (EMG) signals, and torque during elbow passive extension-flexion. One set of 10 passive elbow extension and flexion movements was performed for data acquisition at each angular velocity, including 60, 90, 120, 150 and 180 degrees per second (degrees/sec). Electromyographic data were collected from the biceps brachii and the triceps brachii. Torque data were collected from sensors around the wrist. RESULTS: We were able to detect EMG activity and torque in all subjects by using the new portable hand-driven isokinetic system. EMG activity and torque increased with incremental increase of angular velocities. The joint angle of maximal EMG activity according to different angular velocities did not show any significant difference (116degrees-127degrees in elbow extension and 37degrees-66degrees in elbow flexion). The joint angles of maximal torque according to different angular velocities were not significantly different either. CONCLUSION: Using the portable hand-driven isokinetic system on the elbows of normal subjects, we were able to obtain expected results. By considering our normal findings of the elbow stretch reflex using this system, we propose that the various aspects of spasticity-related data can be measured successfully.

Biomechanical Assessment with Electromyography of Post-Stroke Ankle Plantar Flexor Spasticity

Spasticity has been defined as a motor disorder characterized by a velocity-dependent increase in tonic stretch reflex (muscle tone). Muscle tone consists of mechanical-elastic characteristics, reflex muscle contraction and other elements. The aims of this study were to determine whether to assess spasticity quantitatively, and to characterize biomechanical and electromyographic spasticity assessment parameters. These assessment parameters were described by investigating the correlation between clinical measures and the response to passive sinusoidal movement with consecutive velocity increments. Twenty post-stroke hemiplegic patients and twenty normal healthy volunteers were included in the study. Five consecutive sinusoidal passive movements of the ankle were performed at specific velocities (60, 120, 180, and 240 degrees/ sec). We recorded the peak torque, work, and threshold angle using a computerized isokinetic dynamometer, and simultaneously measured the rectified integrated electromyographic activity. We compared these parameters both between groups and between different velocities. The peak torque, threshold angle, work, and rectified integrated electromyographic activity were significantly higher in the post-stroke spastic group at all angular velocities than in the normal control group. The threshold angle and integrated electromyographic activity increased significantly and linearly as angular velocity increased, but the peak torque and work were not increased in the post-stroke spastic group. Peak torque, work, and threshold angle were significantly correlated to the Modified Ashworth scale, but the integrated electromyographic activity was not. The biomechanical and electromyographic approach may be useful to quantitatively assess spasticity. However, it may also be very important to consider the different characteristics of each biomechanical parameter.

Activation of Human Stretch Reflex by Experimental Muscle Pain

OBJECTIVE: This study was performed to investigate the effect of experimental muscle pain on the stretch reflex through electrophysiologic measuring of H-reflex and ankle tendon reflex. METHOD: Muscle pain was produced by the continuous infusion of 5% hypertonic saline into the soleus and tibialis anterior muscles respectively in the fourteen healthy, male volunteers. Control was made with infusion of 0.9% isotonic saline. H-reflex and ankle tendon reflex were recorded at the soleus before, during and 30 minutes after infusion of saline. RESULTS: The amplitude of ankle tendon reflex increased significantly during soleus and tibialis anterior muscle pain by the infusion of hypertonic saline as compared with those of before and after injection. But the H-reflex showed no significant changes during the infusion in either muscles. CONCLUSION: These results have demonstrated a muscle pain increased the amplitude of the stretch reflex without a corresponding increase of the H-reflex amplitude. One explanation could be an increased dynamic sensitivity of the muscle spindles during muscle pain caused by an increased firing of the dynamic gamma-motor neurons.

The Effect of Intrathecal Baclofen Injection on Muscle Stretch Reflex in Spinal Cord Injured Rabbit

OBJECTIVE: To develop an experimental model that is useful to evaluate the effect of antispastic medication administered intrathecally and to titrate the intrathecal baclofen effect quantitatively by using muscle stretch reflex. METHOD: Ten rabbits were laminectomized posteriorly and intrathecal catheter was inserted. Then the spinal cords were contused by 12.5 gx20 cm weight drop around 12th thoracic vertebra. After 8~12 days, muscle stretch reflex was measured before intrathecal baclofen injection (ITBI) and after ITBI 30 minutes, 60 minutes, and 120 minutes. Rabbits' triceps surae were dissected and stretched 5 mm at the rate of 2 mm/sec using a step motor. The change of muscle tension was graphed into the time (length)-tension curve. The slope in the time (length)-tension curve was defined as stiffness index (SI). RESULTS: The measurement of muscle stretch reflex was available in 5 of 10 spinal cord injured rabbits. The proportion of SI reduced significantly at 60 minutes and 120 minutes compared to baseline (p=0.005, p<0.001). CONCLUSION: Our data proved the antispastic effect of ITBI quantitatively by using muscle stretch reflex. We concluded that the quantitative measurement method of the antispastic effect of ITBI will be useful in evaluating antispastic effect by intrathecal administration of the other antispastic medications.

The Effect of Gabapentin on Muscle Stretch Reflex in Spinal Cord Injured Rabbit

OBJECTIVE: To document the anti-spastic effect and dose-response relationship of gabapentin (GBP) quantitatively using muscle stretch reflex in spinal cord injured rabbits. METHOD: Spinal cords of 25 rabbits were contused by 20 gx20 cm weight drop in the 11th thoracic spine. After 2 weeks, muscle stretch reflex was measured. Triceps surae was dissected and stretched for 5 mm at the rate of 2 mm/sec and the length-tension curve were obtained. The slope in the length-tension curve was defined as stiffness index (SI). After baseline measurement, group I (n=6) received 50 mg/kg GBP IM injection and group II (n=8) received 100 mg/kg GBP IM injection, but control group (n=5) did not. Muscle stretch reflex was measured again after 30 minutes and 60 minutes, and then after sciatic nerve section. Active tension was calculated by subtracting passive tension from total tension. Proportion of SI was calculated by dividing follow-up SI with baseline SI. RESULTS: The proportion of SI of active tension reduced significantly at 30 minutes and 60 minutes compared to baseline (p<0.001, p<0.001). The proportion of SI of active tension in both group I and group II reduced significantly than control group (p=0.041, p<0.001). The proportion of SI of active tension in group II reduced than group I, but it was not statistically significant (p=0.166). CONCLUSION: The GBP reduced significantly muscle stretch reflex in spinal cord injured rabbits and showed dose-response tendency.

Effect of Visual input on stretch responses of ankle muscles during movements to absorb impact / 体力科学

The purpose of this study was to examine the effect of the different visual and vestibular inputs on EMG response of ankle muscles during movement to absorb impact in sliding down a slope. Thereby, our research focused on the relationship between preactivation (PA) in central program and stretch reflex induced by dorsiflexion immediately after impact. The subjects were nine healthy males. Movements were conducted using a special sliding apparatus. Conditions included sliding down a lower 15°slope with eyes open (Low) and with eyes closed (Low-Closed), and a higher 20°slope with eyes open (High) . PA prior to impact indicated the co-contraction of the medial gastrocnemius (MG) and tibialis anterior (TA) . PA levels in those muscles were significantly higher during High than during Low-Closed (p<0.05) . In contrast, PA of the coleus (Sol) was low in all test conditions. After impact, however, the stretch reflex of Sol during Low-Closed was greater than other test conditions. Because muscle stretch velocities and PA levels of Sol among all test conditions remained unchanged, these results suggest that different visual inputs could change the response of stretch reflex by modulations in reflex gain.

Change of Stretch Reflex in Spinal Cord Injured Rabbit: Experimental Spasticity Model

OBJECTIVE: The purpose of this study is to develop an experimental spinal cord injury spasticity model using rabbits and to evaluate a quantitative spasticity measure. METHOD: After an general anesthesia, 19 rabbits out of total 24 rabbits were laminectomized posteriorly and the spinal cords contused with 15 g 20 cm weight drop around 11th and 12th thoracic cord. After two weeks, behavioral analysis and clinical measurements of hindlimb spasticity were assessed. After that, rabbits' triceps surae was dissected and the length-tension plot was obtained by stretching it 5 mm, 2 mm/sec. And then the stiffenss of stretch reflex was determined from the length-tension plot. The stiffness of stretch reflex of the five normal control group was measured. RESULTS: 1) The measure was possible among 15 out of 19 spinal cord injured rabbits. One out of 19 rabbits was died from urinary infection. Two rabbits was died from intraoperative bleeding at 2 weeks. Another one was excluded from the measurement due to joint contracture. 2) All of 15 rabbits showed clinical spasticity of hindlimb in 2 weeks. The spasticity was increased after the 4th day. 3) On the length-tension plot, the stiffness of stretch reflex of 15 rabbits significantly increased more than that of 5 normal group. 4) The total stiffness is correlated with the deep tendon reflex of knee and muscle tone of ankle. The stiffness of stretch reflex is weakly correlated with the deep tendon reflex of knee, digital hyperreflexia and ankle clonus. CONCLUSION: The experimental spinal cord injury model and the quantitative spasticity measure method would contribute to measure the effect of the new therapy of spasticity more accurately, and to establish a principle of the new therapy. In addition, the study is expected to contribute to establish pathophysiology of spasticity.

Effect of Hopping Tempo on Stretch-Reflex of Function Soleus Muscle at Landing Phase / 体力科学

The purpose of this study was to examine the effect of hopping tempo on the stretch reflex of the soleus muscle at the landing phase during continuous hopping. The M 1 and M 2 components of stretch reflex of the soleus muscle and angular velocity of the ankle joint were recorded at the landing phase during hopping under four hopping tempos with frequencies of 1.0, 1.5, 2.0, and 2.5 Hz. The electromyogram (EMG) activities in the soleus muscle during the landing and the jumping phases were separated under 1.0, 1.5 and 2.0 Hz conditions, but EMG's for both phases were overlapped under 2.5 Hz condition. Furthermore, at 1.0 and 1.5 Hz, a non-active EMG phase was observed between the landing and the jumping phases ; but this non-active phase disappeared at 2.0 Hz. The M 1 and M 2 components at 2.0 Hz showed significantly (p<0.01) larger values than those at 1.0 and 1.5 Hz. However, there was no significant difference observed between the components at 1.0 and 1.5 Hz. The M 2 component showed a significantly (p <0.01) smaller value than the M 1 component at 1.0 and 1.5 Hz ; but there was no significant difference at 2.0 Hz. The angular velocity of the ankle joint showed no significant difference under any of the conditions. These findings suggest that stretch reflex at landing during hopping may be inhibited at the motion pattern of the inactive phase between the landing and the jumping phases in EMG's. In addition, the stretch reflex is not only related to mechanical muscle stretching, but is also under the influence of the superior nerve center.

Hyperactive Stretch Reflexes as a Prognostic Factor of Ambulation in the Children with Spastic Diplegia

OBJECTIVE: The purpose of this study was to investigate the influence of hyperactive stretch reflexes and contralateral adductor spread on the prognosis of gait in cerebral palsy with spastic diplegia and to investigate the reflex characteristics of spastic patients according to motor development. METHOD: Thirty three children with spastic diplegia were examined. Compound muscle action potentials elicited by electrical hammer were used for quantification of stretch reflexes. Clinical spasticity was evaluated with the modified Ashworth scale and re-evaluation was done at least for 18 months. The patients were classified as 3 groups according to the stage of motor development: Group I consisted of children who were unable to sit; Group II children were able to pull to stand but unable to walk independently; Group III children could walk independently more than ten steps. Reflex irradiation, amplitudes of compound muscle action potentials, amplitude ratios, and Ashworth scores were analyzed and compared between the groups. Twenty four normal infants and 18 children were examined as control. RESULTS: Contralateral adductor responses were elicited with patellar tendon tap stimulation in all spastic diplegic children. The amplitudes of contralateral adductor were 2.41 mV in group I, 1.75 mV in group II, and 1.21 mV in group III. The amplitude ratio of contralateral adductor to rectus femoris were 0.53 in group I, 0.40 in group II, and 0.26 in group III, respectively, and correlated with the degree of spasticity. CONCLUSION: The stretch reflex responses in children with cerebral palsy with spastic diplegia were highly exaggerated, and correlated with motor development. Spread of reflexes to contralateral adductor muscle would be in clinical and electrophysiological value.

The Significance of Stretch Reflex Threshold Speed in Quantitative Assessment of Spasticity

OBJECTIVE: This study was designed to evaluate the usefulness of stretch reflex threshold speed (SRTS) in biomechanical assesment of spasticity of hemiplegic patients. METHOD: Thirty-eight hemiplegic patients and twenty-seven control subjects were studied. The spasticity of ankle plantar flexor muscles were assessed both clinically and biomechanically. Modified Ashworth scale (MAS) and Brunnstrom stage were used in clinical assessment. For biomechanical assessment, ankle plantar flexor muscles were stretched isokinetically while EMG signals were recorded simultaneously. SRTS was defined as a minimum angular velocity in which EMG signals evoked by stretch reflex were recorded. RESULTS: SRTSs of ankle plantar flexors were 128.1 47.1o/sec in control group, 163.7 79.7o/sec in intact legs, and 83.4 69.1o/sec in involved legs of hemiplegic group. STRS was significantly lower in involved legs of hemiplegic group than in intact legs of hemiplegic group and control group. Significant reverse correlation was observed between SRTS and MAS. There was significant difference in SRTS between MAS 0 group and other groups. The patients with Brunnstrom stage 3 and 4 groups showed decreased SRTS compared to the patients with other groups. CONCLUSION: SRTS is thought to reflect increased excitability of stretch reflex and seems to be one of useful parameters in quantitative assessment of spasticity.

Titration of Phenol Nerve Block Effects on Peripheral Nerves: Electrophysiologic and Mechanical Measurements

OBJECTIVE: The purpose of this study was to titrate the nerve block effect of phenol with different concentrations of phenol solution by electrophysiological and mechanical measurements. METHOD: Right tibial nerves of twenty three adult rabbits were blocked by phenol solution with different concentrations (3%, 5%). Nerve conduction study for compound muscle action potential (CMAP), tension by electrical stimulation, and stiffness (slope) of stretch reflex of the triceps surae were performed after nerve block (4 weeks, 8 weeks, 16 weeks). The ratios of each values of right limb to those of left limb were used to evaluate the nerve block effect. RESULTS: The ratios of CMAP amplitude, tension, and slope of 3% group were 0.36, 0.55, and 0.56 at 4 weeks and those of 5% group were 0.21, 0.25, and 0.58. There were statistically significant differences of the CMAP amplitude and tension ratios, however there was no statistically significant difference of the slope ratio between two groups at 4 weeks. The ratios of CMAP amplitude, tension, and slope of 5% phenol group were increased with time. CONCLUSION: Nerve block effects by 5% phenol solution were greater than 3%. These data suggest that nerve block effect can be titrated with concentration of phenol solution.

An Evaluation of Spasticity Using Pendulum Test and Dynamic Electromyography

OBJECTIVE: The aim of this study was to develop objective evaluation method which reflect the velocity dependent increase of stretch reflex in spasticity using the pendulum test and dynamic electromyography. METHOD: Kinematic analysis for knee angle and angular velocity measurement, and dynamic electromyography were performed simultaneously during pendulum movement of spastic lower extremity in supine position for nineteen spastic hemiplegia patients and ten normal control subjects. Angular relaxation index (ARI), Maximum angular velocity (MAV), Angular threshold (AT) and Angular velocity threshold (AVT) were used for the evaluation of spsticity. RESULTS: 1) ARI was 1.64+/-0.04 in normal, 1.28+/-0.14 in modified Ashworth scale (MAS) I, 1.18+/-0.16 in MAS II, 1.02+/-0.13 in MAS III, 2) MAV was 325.0+/-29.4 in normal, 301.7+/-37.8 in MAS I, 269.2+/-29.7 in MAS II, 232.4+/-28.2 in MAS III, 3) In normal subjects EMG activity did not occur, whereas in spastic hemiplegic patient a stretch reflex appears in thigh muscle. AT and AVT were 57.39+/-4.45, 256.24+/-14.07 in MAS I, 38.59+/-4.26, 184.45+/-12.7 in MAS II, 19.13+/-7.13, 136.06+/-12.88 in MAS III, respectively, 4) Correlation coefficients of the ARI (r= 0.786), AT (r= 0.960), AVT (r= 0.949) showed significantly negative correlations with the MAS. CONCLUSION: 1) AT and AVT are more sensitive parameters than ARI for documenting spasticity in hemiplegic patients. 2) An evaluation of spasticity using pendulum test and dynamic electromyography would provide consistent results with little error and would not be influenced by the change of examiner or environment. Thus we can get very reliable results using this method.

The Quantitative Assessment of Ankle Plantar Flexor Muscle Tone

OBJECTIVE: We designed this study to evaluate muscle tone by using a biomechanical method and to provide data for the future studies about muscle tone. METHOD: We evaluated 29 subjects without known neuromuscalar diseases using the biomechanical method. Both plantar flexors of each subject were passively stretched by isokinetic dynamometer from 30degrees plantar flexion position to 10degrees dorsiflexion position. Peak eccentric torque (PET) and torque threshold angle (TTA) were calculated at angular velocity of 10degrees/sec, 90degrees/sec and 300degrees/sec. Regression lines from torque/position curve at 10degrees/sec and 300degrees/sec were considered an intrinsic stiffness index (ISI) and total stiffness index (TSI). Stretch reflex threshold speed (SRTS) was defined as the minimum speed of plantar flexion movement in which EMG reflex activity in plantar flexor muscles is induced. RESULTS: The mean of TTA was higher in 10o/sec than in 300degrees/sec. The means of ISI and TSI were 0.11+/-0.08, and 0.18+/-0.04. The mean of SRTS was 125.2+/-48.3degrees. No statistical difference in each parameter was found according to the side or gender. CONCLUSION: ISI, TSI, PET, TTA and SRTS using a biomechanical method are thought to be useful parameters for the quantitative assessment of muscle tone change of ankle plantar flexors.

Significance of transient decrease in sustained tension preceding rapid muscle contraction in man / 体力科学

The purpose of this study is to investigate significance of transient decrease in sustained tension preceding rapid muscle contraction in elbow flexor muscles.<BR>Before rapid voluntary contraction, steady forces below 20% of the maximum contraction were maintained, and each transient decreas was detected by using high sensitive strain gauge (FD pick-up) with EMG of brachial biceps and triceps muscles. And girth and length changes of the biceps brachii muscle with the tension decrease were detected by using rubber strain-gauge method and X-ray technique, respectively.<BR>The following results were obtained<BR>1) The transient decrease of steady forces were observed during the premotion silent period. Amount and duration of the transient tension decrease were below 20% of each steady force and 100 ms, respectively.<BR>2) Amount of the transient tension decrease inversely correlated to time to half Pmax on the rapid tension development. (p<0.001)<BR>3) Amount of the transient tension decrease was significantly coefficient with decrement of girth of upper arm. (p<0.001)<BR>4) A distance between two Cu wire apexes inserted into biceps brachii muscle shortened with increment of muscle force.<BR>These results suggest that before rapid muscle contraction stretch of biceps brachii muscle transiently occure, and that the stretch accelerate the following shortning velocity of the muscle via a stretch reflex.