No abstract

Measuring exercise-induced muscle activity is essential in sports medicine. Previous studies proposed measuring transverse relaxation time (T 2 ) using muscle functional magnetic resonance imaging (mfMRI) to map muscle activity. However, mfMRI uses a spin-echo (SE) sequence that requires several minutes for acquisition. We evaluated the feasibility of T 2 mapping of muscle activity using ultrafast imaging, called fast-acquired mfMRI (fastmfMRI), to reduce image acquisition time. The current method uses 2 pulse sequences, spin-echo echo-planar imaging (SE-EPI) and true fast imaging with steady precession (TrueFISP). SE-EPI images are used to calculate T 2 , and TrueFISP images are used to obtain morphological information. The functional image is produced by subtracting the image of muscle activity obtained using T 2 at rest from that produced after exercise. Final fast-mfMRI images are produced by fusing the functional images with the morphologic images. Ten subjects repeated ankle plantar ‰exion 200 times. In the fused images, the areas of activated muscle in the fast-mfMRI and SE-EPI images were identical. The geometric location of the fast-mfMRI did not diŠer between the morphologic and functional images. Morphological and functional information from fast-mfMRI can be applied to the human trunk, which requires limited scan duration. The diŠerence obtained by subtracting T 2 at rest from T 2 after exercise can be used as a functional image of muscle activity.

Abstract.[Purpose] Myofascial release is a manual soft tissue technique that is frequently used in physical therapy, but few reports on the effectiveness of myofascial release are available. We compared the effects of myofascial release and stretching on range of motion, muscle stiffness, and reaction time. [Subjects and Methods] Forty healthy individuals were randomly allocated to four groups: myofascial release for quadriceps; myofascial release for hamstrings; stretch for quadriceps; and controls.[Results] Active range of motion was significantly increased in the two myofascial release groups and the stretch group. Passive range of motion was significantly increased by myofascial release in the quadriceps and stretching groups. No significant differences in muscle stiffness were seen between before and after the interventions. However, premotor time was significantly reduced by myofascial release in the quadriceps and hamstrings groups, with significant differences observed in this parameter between both the quadriceps and hamstrings groups and controls after the interventions. Compared to controls, reaction time was significantly lower after the interventions in the quadriceps and hamstrings groups.[Conclusion] Myofascial release improves not only range of motion, but also ease of movement.

Abstract.[Purpose] Post-stroke treatment regimens include symmetrical movement,reciprocal movement and alternating movement which may be performed accordingly as the patients progress. However, as far as the authors know, there are no reports regarding the differences in neural circuitry involved in each movement. [Subjects and Methods] We analyzed the brain activity of 23 right-handed healthy subjects when performing three different bimanual movements using functional magnetic resonance imaging (fMRI).[Results] Performance of the bimanual tasks showed significant bilateral activation in the sensorimotor area (SMC) under all 3 conditions, the lowest increase in activation was under the alternating condition, with more activation in the right SMC than in the left. Bilateral supplementary motor area (SMA) activated during performance under all 3 conditions. In particular, under alternating condition, significant increase of activation was observed in bilateral SMA. Bilateral premotor area and thalamus were activated, significant increases in activation were observed in the right hemisphere. Bilateral cerebellum showed activation under symmetrical and alternating conditions but not under the condition of reciprocal hand grasps, significant increases in activation were observed in the right. [Conclusion] Moreover, analysis of the brain activity associated with the three bimanual movements suggested involvement of different circuits of subcortical nerve base structures, respective to the tasks. It is considered that the findings may be used as reference data concerning which of the bilateral movements should be employed in rehabilitation according to the brain injury.

Purpose: This study aimed to determine if hamstring-strain-injury risk factors related to muscle structure and morphology differed between rugby union players and controls. Methods: The biceps femoris long head (BFlh) fascicle length and passive muscle stiffness and relative and absolute muscle volume of knee flexors (KF) and extensors (KE) were measured in 21 male subelite rugby players and 21 male physically active nonathletes. Results: BFlh fascicle length was significantly longer (mean difference [MD] = 1.6 [1.7] cm) and BFlh passive muscle stiffness was significantly higher in rugby players (MD = 7.8 [14.8] kPa). The absolute BFlh (MD = 71.9 [73.3] cm3), KF (MD = 332.3 [337.2] cm3), and KE (MD = 956.3 [557.4] cm3) muscle volumes were also significantly higher in rugby players. There were no significant differences in the relative BFlh and KF muscle volumes. The relative KE muscle volumes were significantly higher in rugby players (MD = 2.3 [3.7] cm3/kg). However, the percentage BFlh fascicle length:KE (MD = −0.1% [0.1%]), BFlh/KE (MD = −0.9% [1.9%]), and KF:KE (MD = −4.9% [5.9%]) muscle volume ratios were significantly lower in the rugby players. BFlh muscle volume significantly correlated with BFlh fascicle length (r = .59, r2 = .35) and passive muscle stiffness (r = .46, r2 = .21). Conclusion: Future prospective studies should examine whether there are threshold values in BFlh passive muscle stiffness and BFlh fascicle length:KE, BFlh:KE, and KF:KE muscle volume ratios for predicting hamstring strain injuries.