Correlation between peak expiratory flow rate and pectoralis muscle length

Background: Peak expiratory flow rate (PEFR) is a measure of the maximum speed of exhalation after a deep inspiration. The peak expiratory flow is measured by a device named peak flow meter. This study concentrates on the correlation of the PEFR with the pectoral muscle length.Methods: It is a cross sectional study of 30 convenient samples based on gender distribution where the PEFR and pectoralis muscle length were measured in the subjects.Results: Statistical analysis shows that there is a significant correlation between right pectoralis major general muscle length and PEFR (p=0.030), left pectoralis major general muscle length and PEFR (p=0.014), right pectoralis major clavicular end muscle length with PEFR (p=0.010).Conclusions: There is a significant correlation between peak expiratory flow and pectoralis muscle length.

The Change of Rectus Muscle Length Caused by Traction With Muscle Hooks in Strabismus Surgery-the First Report

PURPOSE: To evaluate changes in muscle length when retracting the extraocular rectus muscle with muscle hooks during strabismus surgery. METHODS: Forty-four rectus muscles of 42 patients consecutively resected in two hospitals (A, B) were included in this study. After isolation of the rectus muscle, the length of the muscle was recorded and the portion to be resected was marked using gentian violet stain on the tip of calipers. After the rectus muscle was retracted with two muscle hooks in either direction, its length was measured again with the calipers. RESULTS: The length of the rectus muscle was not changed by retraction in 25 of 44 muscles (56.8%). The length of the muscle was changed by 0.5 mm in 13 muscles (29.5%) and by 1mm in six muscles (13.6%). Changes of rectus muscle length over 0.5 mm were observed in 15 of 27 muscles of patients treated at hospital A (55.5%) and four of 17 muscles of patients treated at hospital B (23.5%). The results for the two hospitals were significantly different (p=0.037). CONCLUSIONS: Small errors in measurement can occur when muscle resections are performed during strabismus surgery. Institutional or clinician related factors may explain variations in error rates between hospitals.

The Effect of Muscle Length and Excursion on Myostatic Contracture : A Study in Rabbit Soleus Muscles / 대한정형외과연구학회지

PURPOSE: The purpose of this study was to determine the effect of preserving muscle length or excursion on the progression of myostatic contracture after tendon injury in a rabbit soleus tenotomy model. MATERIALS AND METHODS: Forty rabbits underwent tenotomy of the soleus muscles bilaterally and the tendons were managed according to the five experimental groups (N=40). Group A was a tendon-lengthening group maintaining a half of the excursion. In group B, maximal muscle length was maintained and in group C, resting muscle length was maintained. In group D, the tendon was allowed to undergo myostatic contracture and in group E, the tendon was partially transected and repaired. Four and eight weeks postoperatively, soleus muscles were harvested from each hindlimb and histomorphometric evaluations were performed to measure the connective tissue and fiber cross-sectional areas. Electrophysiologic studies were carried out to measure the compound muscle action potential to assess the number of functioning muscle fibers. RESULTS: The results showed that maximal muscle length preservation (Group B) was the most protective in preventing muscle contracture within 4 weeks of tenotomy, but this protective effect was gradually offset by prolonged immobilization, and 8 weeks after tenotomy, maintenance of excursion (Group A) was the most protective. CONCLUSION: These observations can be useful in the intraoperative evaluation of myostatic contracture in neglected tendon ruptures, and be applied to the management of acute tendon injuries to prevent myostatic contracture when immediate anatomical reconstruction cannot be performed.

The Quantitative Measurement of Spasticity Using Change of Muscle Length during Pendulum Test

OBJECTIVE: The aim of this study was to develop objective evaluation method of spasticity which reflects the characteristics of lengthening velocity-dependent stretch reflex of spasticity. METHOD: Kinematic analysis for knee angle and rectus femoris muscle lengthening parameters, and dynamic EMG were performed simultaneously during pendular movement of spastic lower leg for thirty two patients with spasticity and ten normal control subjects. Angular parameters consist of angular relaxation index (ARI), maximal angular velocity (MAV), angular threshold (AT) and angular velocity threshold (AVT). And lengthening parameters consist of lengthening relaxation index (LRI), maximal lengthening velocity (MLV), lengthening threshold (LT) and lengthening velocity threshold (LVT). RESULTS: 1) ARI, MAV, AT, and AVT according to Modified Ashworth scale (MAS) were 1.32+/-0.11, 303.84+/-45.11 deg/sec, 44.19+/-13.81 deg, 262.15+/-33.54 deg/sec in MAS I, 1.16+/-0.16, 279.92+/-42.94 deg/sec, 30.33+/-6.02 deg, 247.65+/-35.92 deg/sec in MAS II, and 0.95+/-0.14, 241.31+/-19.98 deg/sec, 20.55+/-2.68 deg, 209.11+/-48.11 deg/sec in MAS III (P<0.05). 2) LRI, MLV, LT, and LVT according to MAS were 1.27+/-0.11, 0.58+/-0.07, 1.164+/-0.14, 0.53+/-0.05 in MAS I, 1.12+/-0.09, 0.53+/-0.05, 1.150+/-0.08, 0.42+/-0.04 in MAS II, and 0.99+/-0.10, 0.44+/-0.01, 1.137+/-0.15, 0.36+/-0.02 in MAS III (P<0.05). 3) There were significant correlation between various pendulum test parameters and MAS. CONCLUSION: Muscle lengthening parameters as well as knee angular parameters were sensitive parameters reflecting the degree of spasticity. LVT is the most sensitive parameter among all parameters (p<0.01).

Changes of Compound Muscle Action Potentials Related to Voluntary Muscle Contraction and Alteration of Muscle Length in Peripheral Neuropathy

OBJECTIVE: To investigate waveform changes of compound muscle action potentials (CMAPs) related to voluntary muscle contraction and alteration of muscle length and to evaluate the effect of peripheral neuropathy on temporal and spatial summations of CMAPs. METHOD: The influence of voluntary muscle contraction and alteration of muscle length on CMAP was studied in 37 median nerves of 21 patients with median neuropathy. RESULTS: In patients with no apparent axonopathy, temporal summation was partially disturbed without significant change of spatial summation. Shortening of muscle length or voluntary contraction produced a physiologic improvement of spatial and temporal summations. There was a decrease in temporal and spatial summations, more prominent in temporal summation, with lengthening of the muscle. In axonopathy, spatial summation was markedly deteriorated with partial reduction of temporal summation. Spatial summation was not affected by the change of muscle length or voluntary contraction. Temporal summation was improved by muscle shortening or voluntary contraction and was decreased by muscle lengthening. CONCLUSION: Peripheral neuropathy has an effects on physiological spatial and temporal summations of CMAPs. Temporal summation is preferentially decreased in cases without axonopathy. When axonopathy is apparent, spatial summation is profoundly disturbed with partial reduction of temporal summation.

Adaptability of Extraocular Muscle of Rabit in Experimental Exotropia

Fusion loss or anomaly of eye muscle and its nerve is a cause of strabismus. This induces adaptation of vergence and muscle length, the mechanisms of which are normally responsible for long-term maintenance of ocular alignment and orthophorization. To determine variability of muscle length adaptation according to age, we divided white rabbits into three groups: Group I(less than 8 weeks of age and 15000gm of body weight), Group II(10~14 weeks and 1500~2000gm), GroupIII(more than 16 weeks and 2500gm). Under local anesthesia with intravenous pentobarbital sodium, the right eyeball was fixed in exotropic position by suturing through the periosteum of the lateral canthal region with 5-o polypropylene. The muscles of left eye were not operated and served as a control. We examined electron microscopically the changes in sarcomere of the experimental right medial rectus(RMR) and right lateral rectus(RLR) after sacrificing four rabbits of each group at 1, 2 and 4 weeks, respectively. Regardless of age, when the muscle(RLR) was immobilized in the lengthened position, sarcomeres were added on and its length decreased, and when the muscle(RMR) was immobilized in the shortened position, sarcomeres were lost and its length increased. In conclusion, the study revealed that experimental extraocular muscle of rabbit is adapted in the direction to produce maximal power of its muscle and maintain ocular alignment constantly.

Utilization and significance of girth changes in human muscles following contraction: A case of handgrip / 体力科学

To clarify length changes of human muscle, forearm girth was recorded during various handgrips by using the rubber-strain-gauge method.<BR>Subjects quickly lifted loads of 10, 20, 30% of the maximum grip strength (MVC) at a distance of 2 cm, and/or lifted and lowered those loads with the rhythm of 1 Hz.<BR>In isometric condition, handgrip was performed with muscle strength for several seconds in the same conditions as the above. Fatiguing successive contraction was performed with muscle strength of 30% MVC for a few minutes.<BR>1) During ballistic contraction of forearm flexors, differences between the onsets of its discharge and the increase in forearm girth were about 20 ms in all conditions. The increase in forearm girth occurred prior to the onset of the rise in the loads, and its extent depended on the loads.<BR>2) In repetitive handgrips, changes of forearm girth in the muscle contraction phase were similar to those of the ballistic contractions. In the muscle relaxation, recovery of forearm girth to its resting level was delayed with increase of the loads.<BR>3) Forearm girth during successive contraction for a short time remained at an approximately steady level, while its extent depended on the muscle strength. During fatiguing successive contraction, forearm girth gradually increased with an increase in muscle discharge.<BR>These results suggest that length change in human muscle occures during muscle contraction in isometric conditions. Furthermore, this method is useful for the study of the human muscle shortening and lengthening, as to the muscle activity of concentric conditions and muscle relaxation process, even when there is no agreement of force-EMG relation.

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.