ABSTRACT
The purpose of this study was to examine the recruitment state of synergistic muscles in the thigh muscles in leg press exercise with and without pre-fatigue method using transverse relaxation time (T2) on muscle functional magnetic resonance imaging (MRI). Nine healthy male subjects performed the following two types of exercise trials on separate days: 1) 5 sets of a leg press exercise with pre-fatigue method, which consisted of 3 sets of knee extension exercise (LP-pre), 2) 5 sets of a leg press exercise without pre-fatigue method (LP). Both exercises were performed at a load of 80% one-repetition maximum. Before and immediately after exercise, T2-weighted MR images of right-thigh were taken to calculate T2 values of twelve-thigh muscles. The T2 values for quadriceps femoris muscle and hamstrings in LP increased significantly after the exercise, except in the adductor magnus, adductor longus, gracilis, and sartorius. In contrast, the T2 values for all of the twelve-thigh muscles in LP-pre increased significantly after the exercise. Upon comparison between the two trials, the percentage changes in T2 value for the adductor magnus, adductor longus, and sartorius in LP-pre were found to be significantly greater than those in LP. These results suggest leg press exercise with pre-fatigue method may be effective to increase activity of synergistic muscles in thigh muscles during exercise.
ABSTRACT
Objective To assess the contraction and coordination changes in the anterior and posterior thigh muscles of patients recovering from cerebral infarction,and to provide objective references for targeted rehabilitation programs. Methods Eighteen cerebral infarction patients with mild hemiparesis (the patient group) and eighteen age- and sex-matched healthy volunteers (the healthy group) were investigated. The surface-electromyographic (sEMG) signals of their vastus medialis,rectus femoris,vastus lateralis,biceps femoris,semitendinosus and semimembranosus were recorded during knee joint flexion and extension in the prone position.The sEMG signals from both legs were recorded for the patient group,but only from the left leg in the healthy group.The standardized root mean square (stRMS) signals and the co-contraction ratios (CRs) were compared and analysed, Results The stRMSs of the rectus femoris,vastus lateralis and vastus medialis on the patients' affected side during knee extension were significantly higher than those in the healthy group at baseline and follow-up.The stRMSs of the biceps femoris and semitendinosus-semimembranous on the patients' unaffected side were significantly higher than those of the affected side and the healthy group during knee flexion at baseline.The CRs during knee flexion on the patientsˊ affected side at baseline and follow-up were significantly higher than those of the unaffected side at baseline. Conclusions After cerebral infarction,the functioning of both the anterior and posterior thigh muscles on the affected side are impaired.The rectus femoris are the most severely impaired knee extensors,and the biceps femoris,semitendinosus and semimembranous are impaired equally in knee flexion.The thigh flexors and extensors lose their normal antagonist-agonist contraction modes.The functions of both the anterior and posterior thigh muscles should be emphasized during rehabilitation to improve abnormal contraction.
ABSTRACT
Study on the sites of nerve entrance in innervation of skeletal muscles is important in the field of anatomy, histology, physiology and pathology, and since 19 th century, many researchers have been engaged in the macroscopical investigations on nerve entrance of muscles. However, their results were not always precise, because they seemed to employ macroscopical methods without measuring a length of muscles and a distance between origin and insertion of various muscles in thigh<BR>In this paper, first, the muscle length was determined by measuring the distance between origin and insertion directly (designated here as“direct method”) or by measuring the length of muscles along their course (designated here as“indirect method”) by scale. Concomitantly, the number and diameter of major innervated nerves of each muscle were also examined. Next, the distance between nerve entrance and the origin of 9 thigh muscles were carefully measured. The difference of the values obtained referring to sex and age was also surveyed. Adding to it, the correlation between the sites of nerve entrance and that of muscle belly was also studied. The details of respite were ae fn11imr<BR>1) The values of muscle length obtained from direct and indirect methods were compared in paying attention to each belly of muscles. 10 specimens in M, sartorius and M, rectus femoris were used for it. The difference of values between direct and indirect methods was negligible, that is, only 1 to 2.5% difference are there respectively.<BR>2) The number of major nerve entering into each muscle were one or two. The number of major nerves and their diameter (parenthesized) of 21 specimens were as follow; one (1.6 mm) for M, sartorius, two (1.6 mm) for M. rectus femoris, two (2.4 mm) for M, vastus medialis and M. vastus lateralis, one (1.8 mm) for M, gracilis, one (1.7 mm) for M. adductor longus, two (2.4 mm) for M, biceps femoris (caput longum), two (2.5 mm) for M, semitendinosus and two (2.6 mm) for M, semimembranosus.<BR>3) Using 41 specimens, the sites of nerve entrance where one or two major nerves were entered into thigh muscles were measured with the indirect methods. The sites of nerve entrance were indicated with the ratio calculated from the formula described in Result-C. Their sites were 21.4% from the origin for M, sartorius, 14.9% and 25.5% for M. rectus femoris, 22.6% and 39.3% for M. vastus medialis, 17.0% and 35.1% for M, vastus lateralis, 22.3% for M, gracilis, 44.7% for M, adductor longus, 22.1% and 38.6% for M. biceps femoris (caput longum), 15.5% and 43.0% for M. semitendinosus, and 46.7% and 61.7% for M, semimembranosus. However, the difference in the sites of nerve entrance related to sex and age was hardly in those specimens.<BR>4) The difference between the sites of nerve entrance (either one or two) and muscle belly was evident in M, vastus medialis and M, adductor longus. The values of deviation in M. vastus medialis and M. adductor longus stood about at 20%. The difference of the other muscles (M. sartorius, M, rectus femoris, M, vastus lateralis, M, gracilis, M, biceps femoris; caput longum, M, semitendinosus, M, semimembranosus) stood at 3 to 7%.<BR>5) Some discussions were devoted to the relationship of sites between nerve entrance in anatomy and motor point in kinesiology.