scholarly journals Plantar flexor moment arm and muscle volume predict torque-generating capacity in young men

2014 ◽  
Vol 116 (5) ◽  
pp. 538-544 ◽  
Author(s):  
Josh R. Baxter ◽  
Stephen J. Piazza
Keyword(s):  
Plantar Flexion ◽  
Young Men ◽  
Knee Extensor ◽  
Muscle Volume ◽  
Joint Torque ◽  
Muscle Size ◽  
Plantar Flexor ◽  
Moment Arm ◽  
Joint Rotation ◽  
Moment Arms

Muscle volume is known to correlate with maximal joint torque in humans, but the role of muscle moment arm in determining maximal torque is less clear. Moderate correlations have been reported between maximal isometric knee extensor torque and knee extensor moment arm, but no such observations have been made for the ankle joint. It has been suggested that smaller muscle moment arms may enhance force generation at high rates of joint rotation, but this has not yet been observed for ankle muscles in vivo. The purpose of the present study was to correlate plantar flexor moment arm and plantar flexor muscle volume with maximal plantar flexor torque measured at different rates of plantar flexion. Magnetic resonance imaging was used to quantify the plantar flexor moment arm and muscle volume of the posterior compartment in 20 healthy young men. Maximal plantar flexor torque was measured isometrically and at three plantar flexion speeds using an isokinetic dynamometer. Plantar flexor torque was significantly correlated with muscle volume (0.222 < R2 < 0.322) and with muscle moment arm at each speed (0.323 < R2 < 0.494). While muscle volume was strongly correlated with body mass and stature, moment arm was not. The slope of the torque-moment arm regression line decreased as the rate of joint rotation increased, indicating that subjects with small moment arms experienced smaller reductions in torque at high speeds. The findings of this study suggest that plantar flexor moment arm is a determinant of joint strength that is at least as important as muscle size.

scholarly journals No Correlation Between Plantar Flexor Muscle Volume and Sprint Performance in Sprinters

2021 ◽  
Vol 3 ◽  
Author(s):  
Yuto Miyake ◽  
Tadashi Suga ◽  
Masafumi Terada ◽  
Takahiro Tanaka ◽  
Hiromasa Ueno ◽  
...  
Keyword(s):  
Sprint Performance ◽  
Muscle Volume ◽  
Triceps Surae ◽  
Joint Torque ◽  
Muscle Size ◽  
Plantar Flexor ◽  
Plantar Flexors ◽  
Simple Assumption ◽  
Flexor Muscles ◽  
Plantar Flexor Muscles

The plantar flexor torque plays an important role in achieving superior sprint performance in sprinters. Because of the close relationship between joint torque and muscle size, a simple assumption can be made that greater plantar flexor muscles (i.e., triceps surae muscles) are related to better sprint performance. However, previous studies have reported the absence of these relationships. Furthermore, to examine these relationships, only a few studies have calculated the muscle volume (MV) of the plantar flexors. In this study, we hypothesized that the plantar flexor MVs may not be important morphological factors for sprint performance. To test our hypothesis, we examined the relationships between plantar flexor MVs and sprint performance in sprinters. Fifty-two male sprinters and 26 body size-matched male non-sprinters participated in this study. On the basis of the personal best 100 m sprint times [range, 10.21–11.90 (mean ± SD, 11.13 ± 0.42) s] in sprinters, a K-means cluster analysis was applied to divide them into four sprint performance level groups (n = 8, 8, 19, and 17 for each group), which was the optimal number of clusters determined by the silhouette coefficient. The MVs of the gastrocnemius lateralis (GL), gastrocnemius medialis (GM), and soleus (SOL) in participants were measured using magnetic resonance imaging. In addition to absolute MVs, the relative MVs normalized to body mass were used for the analyses. The absolute and relative MVs of the total and individual plantar flexors were significantly greater in sprinters than in non-sprinters (all p &lt; 0.01, d = 0.64–1.39). In contrast, all the plantar flexor MV variables did not differ significantly among the four groups of sprinters (all p &gt; 0.05, η2 = 0.02–0.07). Furthermore, all plantar flexor MV variables did not correlate significantly with personal best 100 m sprint time in sprinters (r = −0.253–0.002, all p &gt; 0.05). These findings suggest that although the plantar flexor muscles are specifically developed in sprinters compared to untrained non-sprinters, the greater plantar flexor MVs in the sprinters may not be important morphological factors for their sprint performance.

Muscle Strength, Size, and Composition Following 12 Months of Gender-affirming Treatment in Transgender Individuals

2019 ◽  
Vol 105 (3) ◽  
pp. e805-e813 ◽  
Author(s):  
Anna Wiik ◽  
Tommy R Lundberg ◽  
Eric Rullman ◽  
Daniel P Andersson ◽  
Mats Holmberg ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Muscle Function ◽  
Treatment Initiation ◽  
Hormone Replacement ◽  
Knee Extensor ◽  
Muscle Volume ◽  
Muscle Size ◽  
Thigh Muscle ◽  
Cross Sectional ◽  
One Year

Abstract Context As many sports are divided in male/female categories, governing bodies have formed regulations on the eligibility for transgender individuals to compete in these categories. Yet, the magnitude of change in muscle mass and strength with gender-affirming treatment remains insufficiently explored. Objective This study explored the effects of gender-affirming treatment on muscle function, size, and composition during 12 months of therapy. Design, settings, participants In this single-center observational cohort study, untrained transgender women (TW, n = 11) and transgender men (TM, n = 12), approved to start gender-affirming medical interventions, underwent assessments at baseline, 4 weeks after gonadal suppression of endogenous hormones but before hormone replacement, and 4 and 12 months after treatment initiation. Main outcome measures Knee extensor and flexor strength were assessed at all examination time points, and muscle size and radiological density (using magnetic resonance imaging and computed tomography) at baseline and 12 months after treatment initiation. Results Thigh muscle volume increased (15%) in TM, which was paralleled by increased quadriceps cross-sectional area (CSA) (15%) and radiological density (6%). In TW, the corresponding parameters decreased by –5% (muscle volume) and –4% (CSA), while density remained unaltered. The TM increased strength over the assessment period, while the TW generally maintained their strength levels. Conclusions One year of gender-affirming treatment resulted in robust increases in muscle mass and strength in TM, but modest changes in TW. These findings add new knowledge on the magnitude of changes in muscle function, size, and composition with cross-hormone therapy, which could be relevant when evaluating the transgender eligibility rules for athletic competitions.

scholarly journals Analyzing Moment Arm Profiles in a Full-Muscle Rat Hindlimb Model

Biomimetics ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 10 ◽  
Author(s):  
Fletcher Young ◽  
Christian Rode ◽  
Alex Hunt ◽  
Roger Quinn
Keyword(s):  
Three Dimensional ◽  
Joint Torque ◽  
Fundamental Aspect ◽  
Moment Arm ◽  
Critical Aspect ◽  
Step Cycle ◽  
Moment Arms ◽  
3D Space ◽  
Torque Generation ◽  
Torque Moment

Understanding the kinematics of a hindlimb model is a fundamental aspect of modeling coordinated locomotion. This work describes the development process of a rat hindlimb model that contains a complete muscular system and incorporates physiological walking data to examine realistic muscle movements during a step cycle. Moment arm profiles for selected muscles are analyzed and presented as the first steps to calculating torque generation at hindlimb joints. A technique for calculating muscle moment arms from muscle attachment points in a three-dimensional (3D) space has been established. This model accounts for the configuration of adjacent joints, a critical aspect of biarticular moment arm analysis that must be considered when calculating joint torque. Moment arm profiles from isolated muscle motions are compared to two existing models. The dependence of biarticular muscle’s moment arms on the configuration of the adjacent joint is a critical aspect of moment arm analysis that must be considered when calculating joint torque. The variability in moment arm profiles suggests changes in muscle function during a step.

scholarly journals Normalized metabolic stress for31P-MR spectroscopy studies of human skeletal muscle: MVC vs. muscle volume

1997 ◽  
Vol 83 (3) ◽  
pp. 875-883 ◽  
Author(s):  
M. D. Fowler ◽  
T. W. Ryschon ◽  
R. E. Wysong ◽  
C. A. Combs ◽  
R. S. Balaban
Keyword(s):  
Skeletal Muscle ◽  
Power Output ◽  
Mr Spectroscopy ◽  
Human Skeletal Muscle ◽  
Plantar Flexion ◽  
Metabolic Stress ◽  
Muscle Volume ◽  
Resonance Spectroscopy ◽  
Plantar Flexor ◽  
Spectroscopy Studies

Fowler, M. D., T. W. Ryschon, R. E. Wysong, C. A. Combs, and R. S. Balaban. Normalized metabolic stress for31P-MR spectroscopy studies of human skeletal muscle: MVC vs. muscle volume. J. Appl. Physiol. 83(3): 875–883, 1997.—A critical requirement of submaximal exercise tests is the comparability of workload and associated metabolic stress between subjects. In this study, 31P-magnetic resonance spectroscopy was used to estimate metabolic strain in the soleus muscle during dynamic, submaximal plantar flexion in which target torque was 10 and 15% of a maximal voluntary contraction (MVC). In 10 healthy, normally active adults, (PCr + Pi)/PCr, where PCr is phosphocreatine, was highly correlated with power output normalized to the volume of muscle in the plantar flexor compartment ( r = 0.89, P < 0.001). The same variable was also correlated, although less strongly ( r = 0.78, P < 0.001), with power normalized to plantar flexor cross-sectional area. These findings suggest that comparable levels of metabolic strain can be obtained in subjects of different size when the power output, or stress, for dynamic plantar flexion is selected as a function of plantar flexor muscle volume. In contrast, selecting power output as a function of MVC resulted in a positive linear relationship between (PCr + Pi)/PCr and the torque produced, indicating that metabolic strain was increasing rather than achieving constancy as a function of MVC. These findings provide new insight into the design of dynamic muscle contraction protocols aimed at detecting metabolic differences between subjects of different body size but having similar blood flow capacity and mitochondrial volume per unit of muscle.

scholarly journals The Contribution of Decreased Muscle Size to Muscle Weakness in Children With Spastic Cerebral Palsy

2021 ◽  
Vol 12 ◽  
Author(s):  
Britta Hanssen ◽  
Nicky Peeters ◽  
Ines Vandekerckhove ◽  
Nathalie De Beukelaer ◽  
Lynn Bar-On ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Muscle Weakness ◽  
Plantar Flexion ◽  
Joint Torque ◽  
Muscle Size ◽  
Spastic Cerebral Palsy ◽  
Regression Equations ◽  
Plantar Flexors ◽  
Cross Sectional ◽  
Large Variability

Muscle weakness is a common clinical symptom in children with spastic cerebral palsy (SCP). It is caused by impaired neural ability and altered intrinsic capacity of the muscles. To define the contribution of decreased muscle size to muscle weakness, two cohorts were recruited in this cross-sectional investigation: 53 children with SCP [median age, 8.2 (IQR, 4.1) years, 19/34 uni/bilateral] and 31 children with a typical development (TD) [median age, 9.7 (IQR, 2.9) years]. Muscle volume (MV) and muscle belly length for m. rectus femoris, semitendinosus, gastrocnemius medialis, and tibialis anterior were defined from three-dimensional freehand ultrasound acquisitions. A fixed dynamometer was used to assess maximal voluntary isometric contractions for knee extension, knee flexion, plantar flexion, and dorsiflexion from which maximal joint torque (MJT) was calculated. Selective motor control (SMC) was assessed on a 5-point scale for the children with SCP. First, the anthropometrics, strength, and muscle size parameters were compared between the cohorts. Significant differences for all muscle size and strength parameters were found (p ≤ 0.003), except for joint torque per MV for the plantar flexors. Secondly, the associations of anthropometrics, muscle size, gross motor function classification system (GMFCS) level, and SMC with MJT were investigated using univariate and stepwise multiple linear regressions. The associations of MJT with growth-related parameters like age, weight, and height appeared strongest in the TD cohort, whereas for the SCP cohort, these associations were accompanied by associations with SMC and GMFCS. The stepwise regression models resulted in ranges of explained variance in MJT from 29.3 to 66.3% in the TD cohort and from 16.8 to 60.1% in the SCP cohort. Finally, the MJT deficit observed in the SCP cohort was further investigated using the TD regression equations to estimate norm MJT based on height and potential MJT based on MV. From the total MJT deficit, 22.6–57.3% could be explained by deficits in MV. This investigation confirmed the disproportional decrease in muscle size and muscle strength around the knee and ankle joint in children with SCP, but also highlighted the large variability in the contribution of muscle size to muscle weakness.

scholarly journals Association between plantar flexor muscle volume and dorsiflexion flexibility in healthy young males: ultrasonography and magnetic resonance imaging studies

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Tadashi Suga ◽  
Masafumi Terada ◽  
Keigo Tomoo ◽  
Yuto Miyake ◽  
Takahiro Tanaka ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Muscle Volume ◽  
Muscle Size ◽  
Plantar Flexor ◽  
Passive Stiffness ◽  
Resonance Imaging ◽  
Flexor Muscle ◽  
Joint Flexibility ◽  
Young Males

Abstract Background Although joint flexibility is important for human locomotion, the determinants of joint flexibility are not fully understood. In this study, we examined the relationship between dorsiflexion flexibility and plantar flexor muscle size in healthy young males. Methods and results The dorsiflexion flexibility was assessed using range of motion (ROM) and stiffness during active and passive dorsiflexion. Active ROM was defined as the maximal angle during voluntary dorsiflexion. Passive ROM was defined as the angle at the onset of pain during passive dorsiflexion. Passive stiffness was calculated as the slope of the linear portion of the torque-angle curve between 10º and 20º dorsiflexion of the ankle during passive dorsiflexion. In the first study, the plantar flexor muscle volume (MV) in 92 subjects was estimated on the basis of the lower leg length and plantar flexor muscle thickness, as measured using ultrasonography. The estimated plantar flexor MV correlated significantly with active ROM (r = -0.433), passive ROM (r = -0.299), and passive stiffness (r = 0.541) during dorsiflexion (P = 0.01 for all). In the second study, the plantar flexor MV in 38 subjects was measured using magnetic resonance imaging. The plantar flexor MV correlated significantly with plantar flexor active ROM (r = -0.484), passive ROM (r = -0.383), and passive stiffness (r = 0.592) during dorsiflexion (P = 0.05 for all). Conclusions These findings suggest that a larger plantar flexor MV is related to less dorsiflexion flexibility in healthy young males.

scholarly journals Ankle joint mechanics and foot proportions differ between human sprinters and non-sprinters

2011 ◽  
Vol 279 (1735) ◽  
pp. 2018-2024 ◽  
Author(s):  
Josh R. Baxter ◽  
Thomas A. Novack ◽  
Herman Van Werkhoven ◽  
David R. Pennell ◽  
Stephen J. Piazza
Keyword(s):  
Ankle Joint ◽  
Bone Geometry ◽  
Running Economy ◽  
Joint Mechanics ◽  
Moment Arm ◽  
Joint Rotation ◽  
Human Foot ◽  
Moment Arms ◽  
Muscle Work ◽  
Centre Of Rotation

Recent studies of sprinters and distance runners have suggested that variations in human foot proportions and plantarflexor muscle moment arm correspond to the level of sprint performance or running economy. Less clear, however, is whether differences in muscle moment arm are mediated by altered tendon paths or by variation in the centre of ankle joint rotation. Previous measurements of these differences have relied upon assumed joint centres and measurements of bone geometry made externally, such that they would be affected by the thickness of the overlying soft tissue. Using magnetic resonance imaging, we found that trained sprinters have shorter plantarflexor moment arms ( p = 0.011) and longer forefoot bones ( p = 0.019) than non-sprinters. The shorter moment arms of sprinters are attributable to differences in the location of the centre of rotation ( p < 0.001) rather than to differences in the path of the Achilles tendon. A simple computer model suggests that increasing the ratio of forefoot to rearfoot length permits more plantarflexor muscle work during plantarflexion that occurs at rates expected during the acceleration phase following the sprint start.

The variation in the orientations and moment arms of the knee extensor and flexor muscle tendons with increasing muscle force: A mathematical analysis

2000 ◽  
Vol 214 (3) ◽  
pp. 277-286 ◽  
Author(s):  
A Imran ◽  
R A Huss ◽  
H Holstein ◽  
J J O'Connor
Keyword(s):  
Muscle Force ◽  
Sagittal Plane ◽  
Knee Extensor ◽  
Flexion Angle ◽  
Moment Arm ◽  
Flexor Muscle ◽  
Moment Arms ◽  
Maximum Change ◽  
Knee Muscle ◽  
Hamstrings Tendon

The orientations and moment arms of the knee extensor and flexor muscle tendons are evaluated with increasing values of muscle force during simulated isometric exercises. A four-bar linkage model of the knee in the sagittal plane was used to define the motion of the joint in the unloaded state during 0–120° flexion. The cruciate and collateral ligaments were represented by arrays of elastic fibres, which were recruited sequentially under load or remained buckled when slack. A bi-articular model of the patello-femoral joint was used. Simple straight-line representation was used for the lines of action of the forces transmitted by the model muscle tendons. The effects of tissue deformation with increasing muscle force were considered. During quadriceps contraction resisted by an external flexing load, the maximum change in moment arm of the patellar tendon was found to be 2 per cent at 0° flexion when the quadriceps force was increased tenfold, from 250 to 2500 N. The corresponding maximum change in orientation of the tendon was 3° at 120° flexion. During hamstrings contraction resisted by an external extending load, the maximum change in moment arm of the hamstrings tendon was 8 per cent at 60° flexion when the hamstrings force was increased tenfold, from 100 to 1000 N. During gastrocnemious contraction, the corresponding maximum change for the gastrocnemious tendon was 3 per cent at 0°. The orientations of the flexor muscle tendons in this range of force either remained constant or changed by 1° or less at any flexion angle. The general trend at any flexion angle was that, as the muscle force was increased, the moment arms and the orientations approached nearly constant values, showing asymptotic behaviour. It is concluded that experimental simulations of knee muscle action with low values of the externally applied load, of the order of 50 N, can provide reliable estimates of the relationships between muscle forces and external loads during activity.

scholarly journals Elbow Flexor Strength, Muscle Size, and Moment Arms in Prepubertal Boys and Girls

2006 ◽  
Vol 18 (4) ◽  
pp. 457-469 ◽  
Author(s):  
Louise E. Wood ◽  
Sharon Dixon ◽  
Chris Grant ◽  
Neil Armstrong
Keyword(s):  
Elbow Flexion ◽  
Elbow Flexor ◽  
Muscle Size ◽  
Moment Arm ◽  
Cross Sectional ◽  
Moment Arms ◽  
Prepubertal Boys ◽  
Isometric Torque ◽  
Muscle Cross Sectional Area ◽  
Flexor Strength

The aim of this study was to examine elbow flexion torque, muscle cross-sectional area (CSA), and leverage in boys and girls. Thirty-eight prepubertal children (9.6 ± 0.3 years) volunteered to participate. All performed isometric flexion actions at 10°, 50°, and 90° of elbow flexion. Magnetic resonance imaging was used to assess elbow flexor (EF) muscle CSA and brachialis moment arm lengths. No significant gender differences were observed for any of the variables studied. EF CSA was directly proportional to isometric torque at 50° and 90°. CSA explained between 47% and 57% of torque variance. Moment arm estimates explained 19% of the variance in isometric torque at 90°. These baseline data contribute to our understanding of factors influencing strength variation during childhood.

Sign in / Sign up

Export Citation Format

Share Document