In vivo specific tension of human skeletal muscle

Abstract

In this study, we estimated the specific tensions of soleus (Sol) and tibialis anterior (TA) muscles in six men. Joint moments were measured during maximum voluntary contraction (MVC) and during electrical stimulation. Moment arm lengths and muscle volumes were measured using magnetic resonance imaging, and pennation angles and fascicular lengths were measured using ultrasonography. Tendon and muscle forces were modeled. Two approaches were followed to estimate specific tension. First, muscle moments during electrical stimulation and moment arm lengths, fascicular lengths, and pennation angles during MVC were used (data set A). Then, MVC moments, moment arm lengths at rest, and cadaveric fascicular lengths and pennation angles were used (data set B). The use of data set B yielded the unrealistic specific tension estimates of 104 kN/m(2) in Sol and 658 kN/m(2) in TA. The use of data set A, however, yielded values of 150 and 155 kN/m(2) in Sol and TA, respectively, which agree with in vitro results from fiber type I-predominant muscles. In fact, both Sol and TA are such muscles. Our study demonstrates the feasibility of accurate in vivo estimates of human muscle intrinsic strength.

Changes in pennate muscle architecture after gradual tibial lengthening in goats

“…Numerous studies have examined how the PA affects normal muscle anatomy, architecture, and physiological function (Muhl, 1982;Gans and de Vree, 1987;Lieber and Blevins, 1989;Gans and Gaunt, 1992;Scott et al, 1993;Van Eijden et al, 1997;Ledoux et al, 2001;Maganaris et al, 2001). Previous PA studies have focused only on the PA of the muscle fibers located at the muscle belly surface (Muhl, 1982;Sacks and Roy, 1982;Lieber and Blevins, 1989;Scott et al, 1993;Van Eijden et al, 1997;Ledoux et al, 2001;Maganaris et al, 2001).…”

“…Previous PA studies have focused only on the PA of the muscle fibers located at the muscle belly surface (Muhl, 1982;Sacks and Roy, 1982;Lieber and Blevins, 1989;Scott et al, 1993;Van Eijden et al, 1997;Ledoux et al, 2001;Maganaris et al, 2001). The orientation of these fibers; however, does not represent the orientation of the majority of muscle fibers.…”

“…In vivo measurement of PA during muscle contraction was carried out using ultrasonography (Maganaris et al, 2001). Finally, MRI was used to measure three-dimensional orientation of the skeletal muscle fibers (Scott et al, 1993).…”

“…Both FL and the cosine of PA are components of the standard formula used to calculate the muscle physiological cross-sectional area (PCSA) (Sacks and Roy, 1982;Lieber, 2002), which is the only muscle architectural parameter that is directly proportional to the maximum tetanic tension of the muscle, hence to its ability of force production (Lieber, 2002). Although numerous studies evaluated how the PA affects normal muscle anatomy and physiological function (Muhl, 1982;Gans and de Vree, 1987;Lieber and Blevins, 1989;Gans and Gaunt, 1992;Scott et al, 1993;Van Eijden et al, 1997;Ledoux et al, 2001;Maganaris et al, 2001), little is known about the effect of gradual distraction on muscle fiber PA and PCSA.…”

A parallel robot for ankle rehabilitation-evaluation and its design specifications

“…5 shows roll, pitch and yaw wrt time of a foot in extreme rotational movement. Previous measurements of ankle muscle strength have shown that the torque producing potential of the plantraflexors is smaller than 200Nm [21], [16]. For the dorsiflexors and the ankle invertors and evertors the maximum torque values produced during a strength test are smaller than 100Nm [16].…”