To determine the shortening velocities of fascicles of the vastus lateralis muscle (VL) during isokinetic knee extension, six male subjects were requested to extend the knee with maximal effort at angular velocities of 30 and 150 degrees /s. By using an ultrasonic apparatus, longitudinal images of the VL were produced every 30 ms during knee extension, and the fascicle length and angle of penna...

Sarcopenia and muscle weakness are well-known consequences of aging. The aim of the present study was to ascertain whether a decrease in fascicle force (Ff) could be accounted for entirely by muscle atrophy. In vivo physiological cross-sectional area (PCSA) and specific force (Ff/PCSA) of the lateral head of the gastrocnemius (GL) muscle were assessed in a group of elderly men [EM, aged 73.8 yr...

We tested whether explosive resistance training with partial range of motion (ROM) would be as effective full ROM using a noninferiority trial design. Fifteen subjects strength experience took part in an explosive—concentric only—leg press program, three times per week for 10 weeks. One leg was randomly assigned to exercise (ie, 9º) and the other ROM. Before after training, we assessed performa...

The real-time estimation of muscle forces could be a very valuable tool for rehabilitation. By seeing how much muscle force is being produced during rehabilitation, therapists know whether they are working within safe limits in their therapies and patients know if they are producing enough force to expect improvement. This is especially true for rehabilitation of Achilles tendon ruptures where,...

OBJECTIVES Currently, there are no studies combining electromyography (EMG) and sonography to estimate the absolute and relative strength values of erector spinae (ES) muscles in healthy individuals. The purpose of this study was to establish whether the maximum voluntary contraction (MVC) of the ES during isometric contractions could be predicted from the changes in surface EMG as well as in f...

Ultrasound imaging is widely used to measure architectural features of human skeletal muscles in vivo. We systematically reviewed studies of the reliability and validity of two-dimensional ultrasound measurement of muscle fascicle lengths or pennation angles in human skeletal muscles. A comprehensive search was conducted in June 2011. Thirty-six reliability studies and six validity studies met ...

INTRODUCTION When a muscle shortens it must increase in transverse crosssectional area in order to minimize any changes in volume. This increase in cross-sectional area may occur as a bulging in depth or in width. Pennate muscles have structural asymmetries due to the nature of the pennation, and thus may have asymmetries between the bulging in depth or width. Muscle depth can be considered as ...

CONTEXT Professional basketball players have demanding schedules that, in combination with certain underlying physical characteristics and side-to-side strength and power imbalances, may make them vulnerable to lower extremity injuries. OBJECTIVE To examine the relationship among skeletal muscle architecture, lower body power, and games missed because of lower extremity injury (%MISS) in prof...