Muscle Architecture Variables Research Articles

Correlations between Achilles tendon moment arm and plantarflexor muscle architecture variables.

The production of triceps surae plantarflexion moment is complex in that the Achilles tendon moment arm affects the Achilles tendon force by determining the muscle length change and shortening velocity during ankle rotation. In addition, there is evidence for associations between the sizes of muscles and their moment arm at the joints they span. These relationships between muscle architecture and tendon moment arm ultimately affect the muscle's force generating capacity and are thus important for understanding the roles played by muscles in producing locomotion. The purpose of this study was to investigate in vivo the relationship between architecture of two plantarflexors and the Achilles tendon moment arm in a healthy adult population. Ultrasound-based measurements were made of the architecture (fascicle length, muscle volume, physiological cross-sectional area, and anatomical cross-sectional area) of the lateral and medial gastrocnemius and the Achilles tendon moment arm was assessed using a technique that combined ultrasound imaging and motion analysis. Positive correlations were observed between the length (r = 0.499, p = 0.049) and size variables (muscle volume r = 0.621, p = 0.010; ACSA r = 0.536, p = 0.032) of the lateral gastrocnemius and the Achilles tendon moment arm, but correlations were only observed for size variables (muscle volume r = 0.638, p = 0.008; PCSA r = 0.525, p = 0.037; ACSA r = 0.544, p = 0.029), and not the length, of the medial gastrocnemius. These findings suggest lateral gastrocnemius adapts to moment arms to maintain force production throughout the range of motion across individuals, while the medial gastrocnemius does not and is thus better suited for static force generation.

Association between age and muscle function, architecture, and composition in long-distance master runners: a cross-sectional study.

The aim of this study was to describe the muscle function, architecture, and composition of long-distance master runners, and verify the association between age and these variables. Additionally, different clusters of runners were compared based on age and training variables. Forty male runners (≥50 years) reported their training routine and had their muscle function evaluated through maximum knee extensor isometric peak torque (PT) assessed with an isokinetic dynamometer. The cross-sectional area (CSA), pennation angle (PA), fascicle length (FL), muscle thickness (MT), and echo intensity (EI) were evaluated through ultrasound (muscle architecture and composition). The participants were 58.7±6.2 years old and had been training for 18.4±10.3 years, 4 sessions/week with 298.8±164.7 min/week of training. The absolute torque was 226.92±63.44 N·m, and the specific torque (PT/CSA) was 7.29±3.78 N·m/cm2. Regarding muscle architecture, the phase angle was 17.34±4°, the fascicle angle 6.78±1.04 cm, muscle thickness 2.93±0.56 cm, and the cross-sectional area 21.24±5.88 cm2. Concerning muscle composition, the master runners showed echo intensity values of 62.05±11.68 AU. The analysis demonstrated a weak and negative association between age and some muscle architecture variables (CSA and MT) and muscle function (PT). No association was verified between age and muscle composition (EI). Age partially explained CSA, MT, and muscle function changes (13, 11, and 14%, respectively). Participants' high level of physical training might have contributed to the low association between these variables and the lack of association with muscle composition.

Assessment methods of vastus lateralis muscle architecture using panoramic ultrasound: a new approach, test-retest reliability and measurement error

Abstract Extended-field-of-view ultrasonography is a valid alternative to determine the dimensions of the skeletal striated muscle; however, some factors may influence the final measurement. The aim of this study was to determine the test-retest reliability and measurement error of vastus lateralis muscle architecture variables through internal anatomical landmarks and to compare three fixed determined points using extended-field-of-view ultrasonography. Twelve young (24 ± 6 years) adult university male students participated in the study. Images were obtained through extended-field-of-view ultrasonography of the vastus lateralis muscle. Measurements were made for muscle thickness (MT), fascicle length (FL), and fascicle pennation angle (FA) using a method that identifies internal anatomical landmarks. MT was also measured at predetermined distances of 2 cm proximal, 6 cm proximal, and 2 cm distal. One-way ANOVA with repeated measures did not identify any test-retest significant differences for all variables measured. Typical measurement error in centimeters (cm) or degrees (º), coefficient of variation in percentage (%) and intraclass correlation coefficient were MT = 0.07 cm, 2.93%, 0.964; FL = 0.31 cm, 2.89%, 0.947; FA = 0.92°, 4.08%, 0.942; MT 2 cm proximal = 0.10 cm, 3.77%, 0.910; MT 6 cm proximal = 0.27 cm, 9.66%, 0.576; MT 2 cm distal = 0.35 cm, 19.76%, 0.564. MT, FL and FA showed high reliability and low measurement error. Internal anatomical landmarks proved to be more reliable and presented smaller measurement errors when compared to the predetermined distances method.

The Influence of Maturity Status on Muscle Architecture in School-Aged Boys.

To determine the differences in muscle architecture of the lower limb in pre-peak height velocity (PHV), circa-PHV, and post-PHV boys. Muscle architecture variables from both the gastrocnemius medialis (GM) and vastus lateralis (VL) were derived from ultrasonographic images in 126 school-aged boys. One-way analysis of variance using Bonferroni post hoc comparisons was employed to determine between-group differences, and effect sizes were calculated to establish the magnitude of these differences. All muscle architecture variables showed significant small to large increases from pre-PHV to post-PHV, excluding GM fascicle length (d = 0.59-1.39; P < .05). More discrete between-group differences were evident as GM and VL muscle thickness, and physiological thickness significantly increased between pre-PHV and circa-PHV (d > 0.57; P < .05); however, only the VL muscle thickness and physiological thickness increased from circa-PHV to post-PHV (d = 0.68; P < .05). The post-PHV group also showed larger GM pennation angles than the circa-PHV group (d = 0.59; P < .05). The combined results showed that maturation is associated with changes in muscle morphology. These data quantify that the maturity-related changes in muscle architecture variables provide a reference to differentiate between training-induced adaptations versus changes associated with normal growth and maturation.

3D Anatomy and Muscle Architecture of the Human Hand: new approaches for imaging and education

New three‐dimensional digital imaging technologies permit much richer reconstructions of soft‐tissue anatomy. We used algorithmic fiber‐tracking software, or 3D muscle tractography to model the muscle architecture of distal forearm and hand muscles via diffusible iodine contrast‐enhanced computed tomography (DiceCT) of a deidentified donor. Excellent soft‐tissue staining and high CT resolution (&lt;50 μm) allowed for the visualization of many tissues difficult to simultaneously resolve using other imaging modalities, including muscle fascicles, integumentary collagen fibers, as well as bony trabeculae. Muscle fascicles were tracked and modeled as curved cylinders from which fascicle‐specific information, such as length and orientation, was gathered. By modeling numerous fascicles within a whole muscle, we collected muscle‐wide distributions, rather than single‐value estimates, of quantitative muscle architecture variables. These comprehensive data afforded by DiceCT and algorithmic fascicle modeling promise to aid in biomechanical modeling. Further, the volume and fascicle models produced by these methods are an excellent teaching resource in medical education.Support or Funding InformationNSF IOS 1457319, NSF EAR 1631684, Missouri Research Council, Life Sciences Research Fellowship, University of Missouri Department of Pathology and Anatomical SciencesThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Changes in rectus femoris architecture induced by the reverse nordic hamstring exercises

Injuries and mechanical stimuli alter the muscle architecture and, therefore, its function. The changes in the architecture of the rectus femoris (RF) induced by an eccentric training protocol with reverse nordic hamstring exercises (RNHE) have never been studied. Therefore, the aim of the present study was to determine the architectural adaptations of the RF after an eccentric training with RNHE, followed by a subsequent detraining period. Twenty-six subjects performed a first week of control, 8 weeks of eccentric training, concluding with a 4-week period of detraining. The architectural characteristics of the RF were evaluated using 2D ultrasound at rest (pretest: week 1), after the training (post-test: week 9), and at the end of the detraining period (retest: week 13). At the end of the training period, a significant increase in the muscle fascicle length (FL) (t=-8.96, d=2.22, P<0.001), muscle thickness (MT) (t=-8.76, d=2.219, P<0.001), pennation angle (PA) (t=-9.83, d=2.49, P<0.05) and cross-sectional area (CSA) (t=-13.06, d=3.06, P<0.001) was observed. After the detraining period FL, MT, PA and CSA showed a significant decrease. The eccentric training with RNHE may cause changes in the architectural conditions of RF, which, in addition, are also reversible after a 4-week detraining period. The adaptations produced by RNHE may have practical implications for injury prevention and rehabilitation programs, which include the changes in muscle architecture variables.

Efeitos agudos do alongamento estático passivo sobre a arquitetura muscular do vasto lateral de jovens saudáveis

The aim of the study was to investigate the acute effects of passive static stretching (PSS) on the fascicle length (FL) and fascicle angle (FA) of the vastus lateralis muscle (VL) in two different joint positions. Twelve physically active men (26.9 ± 7.5 years, 178.6 ± 7.0 cm, and 82.5 ± 16.8 kg) were placed in the prone position for the acquisition of ultrasound images (US) of VL, registered with extended and totally flexed knee up to the heel contact with the gluteus, before and after a PSS routine comprised of three 30-s repetitions maintained in the maximal discomfort position as reported by the participant. Results of the paired t-test indicated an increase in FL (16.2%; p = 0.012) and reduction in FA (15.5%; p = 0.003) in pre vs. post stretching comparisons for the extended knee position. There was also a significant increase in FL (34%; p = 0.0001) and reduction in FA (25%; p = 0.0007) when compared the extended knee vs. flexed knee positions. There were no significant differences in muscle architecture variables for the flexed knee position. The results showed high and moderate correlation of FL and FA for the extended (r = -0.89 and r = -0.74) and flexed knee (r = -0.76 and r = -0.78) position, pre and post stretching, respectively. It was concluded that the static stretching acutely affects the vastus lateralis muscle architecture only in the extended knee position, but not in the flexed knee position.

Efeitos agudos do alongamento estático passivo sobre a arquitetura muscular do vasto lateral de jovens saudáveis

The aim of the study was to investigate the acute effects of passive static stretching (PSS) on the fascicle length (FL) and fascicle angle (FA) of the vastus lateralis muscle (VL) in two different joint positions. Twelve physically active men (26.9 ± 7.5 years, 178.6 ± 7.0 cm, and 82.5 ± 16.8 kg) were placed in the prone position for the acquisition of ultrasound images (US) of VL, registered with extended and totally flexed knee up to the heel contact with the gluteus, before and after a PSS routine comprised of three 30-s repetitions maintained in the maximal discomfort position as reported by the participant. Results of the paired t-test indicated an increase in FL (16.2%; p = 0.012) and reduction in FA (15.5%; p = 0.003) in pre vs. post stretching comparisons for the extended knee position. There was also a significant increase in FL (34%; p = 0.0001) and reduction in FA (25%; p = 0.0007) when compared the extended knee vs. flexed knee positions. There were no significant differences in muscle architecture variables for the flexed knee position. The results showed high and moderate correlation of FL and FA for the extended (r = -0.89 and r = -0.74) and flexed knee (r = -0.76 and r = -0.78) position, pre and post stretching, respectively. It was concluded that the static stretching acutely affects the vastus lateralis muscle architecture only in the extended knee position, but not in the flexed knee position.

Effect of 6-weeks WBVT on the behaviour of the lower limb muscle fibres during vertical jumping

ABSTRACTThe purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EGWBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg−1; P = 0.001), take-off velocity (0.1 cm · s−1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EGWBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EGWBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men.

Ultrasound for the assessment of peripheral skeletal muscle architecture in critical illness: a systematic review.

To critically evaluate and summarize identified evidence for the use of ultrasound to measure peripheral skeletal muscle architecture during critical illness. Seven electronic databases (Medline, Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, Physiotherapy Evidence Database, Scopus, Excerpta Medica Database, and Web of Science [including Science Citations and Conference Proceedings]) and personal libraries were searched for relevant articles. Cross-referencing further identified references. Quantitative study designs excluding abstracts, published in English, including adult critically ill patients in the ICU, evaluating peripheral skeletal muscle architecture during critical illness with ultrasound were included. Studies using ultrasonographic muscle data as outcome measures in interventional trials were excluded. Performed by one reviewer using a standardized data extraction form and cross-checked by a second reviewer. Quality appraisal was undertaken by two independent reviewers-studies were classified, graded, and appraised according to standardized algorithms and checklists. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adhered to. Seven studies with independent patient cohorts totaling 300 participants were included. One study adopted a case-control design, and the remainder were case series. Ultrasound data demonstrated deficits in a variety of peripheral skeletal muscle architecture variables across a range of muscle groups associated with critical illness. Ultrasound offered more accurate data compared to limb circumference measurement and has excellent reported reliability, but underestimated data acquired via more invasive muscle biopsy. Ultrasound provides clinical utility for assessing the trajectory of change in peripheral skeletal muscle architecture during critical illness, supplementing more detailed characterization, albeit rarely used, from muscle biopsy analysis. Adoption of standardized operating protocols for measurement will facilitate future meta-analysis of data.

Assessment of Muscle Architecture of the Biceps Femoris and Vastus Lateralis by Ultrasound After a Chronic Stretching Program

To evaluate the chronic effects of a static stretching program on the muscle architecture of biceps femoris (BF) and vastus lateralis (VL) muscles in ultrasound (US) images. Randomized controlled longitudinal trial. Biomechanics Laboratory of Physical Education School of the Army, Rio de Janeiro, Brazil. The study included 24 healthy and physically active male volunteers (19.05 ± 1.40 years, 1.73 ± 0.07 m, and 73.15 ± 8.33 kg), randomly allocated to 1 of 2 groups: stretching group (SG, n = 12) and control group (n = 12). The SG was submitted to 3 sets of 30 seconds of static stretching 3 times a week during 8 weeks. Ultrasound equipment (7.5 MHz) was used for the evaluation of BF and VL muscle architecture variables (pennation angle, fiber length, muscle thickness, and fascicle displacement) before and after training. Knee range of motion (ROM) and isometric flexion and extension torque (TQ) were also measured. There were no significant changes in muscle architecture, TQ, and maximum knee flexion angle (P > 0.05). However, maximum knee extension angle (MEA) increased significantly in the SG (pretraining: 159.37 ± 7.27 degrees and posttraining: 168.9 ± 3.7 degrees; P < 0.05). Volume or intensity (or both) of the stretching protocol was insufficient to cause structural changes in the VL and BF muscles. The increase in MEA could not be explained by muscle architecture changes. To describe changes in the VL and BF muscle tendon unit using US after a long-term stretching program to identify which structures are responsible for ROM increase.

Confiabilidade das medidas de arquitetura do músculo Vasto Lateral pela ultrassonografia

As medidas de confiabilidade das análises da arquitetura muscular pela ultrasonografia são importantes referências para estudos aplicados de mecânica muscular. O objetivo deste estudo foi determinar a confiabilidade das medidas de espessura muscular (EM), ângulo de penação (AP) e comprimento da fibra (CF) do músculo Vasto Lateral (VL). As imagens de ultrassom foram obtidas em um grupo (N=14; 22 ± 1,75 anos) em duas visitas (sessenta medidas por indivíduo). Foi calculado o coeficiente de correlação intraclasse (CCI), coeficiente de variação (CV) e erro típico da medida (ETM). Os resultados demonstram alta confiabilidade: CCI AP (0,83 a 0,99), EM (0,96 a 0,99) e CF (0,80 a 0,99); CV AP (3,68 a 6,34%), EM (3,12 a 3,84%) e CF (3,98 a 6,33%) e ETM AP (0,18 a 0,59º); EM (0,014 a 0,15mm) e CF (0,07 a 1,47mm). Essas medidas devem ser consideradas em estudos que analisam o impacto na arquitetura muscular em programas de condicionamento do Vasto Lateral.

Changes in Muscle Architecture and Performance During a Competitive Season in Female Softball Players

The purpose of this research was (a) to examine the performance changes that occur in elite female softball players during 20 weeks of softball training (that included 14 weeks of periodized resistance training [RT]) and (b) to examine the relationship between percent change (%change) in muscle architecture variables and %change in strength, speed, and change of direction performance. Ten female softball players (age = 18.1 ± 1.6 years, height = 166.5 ± 8.9 cm, weight = 72.4 ± 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower-body strength using a 3 repetition maximum for a predicted 1 repetition maximum (1RM) and peak force, peak velocity (PV), and peak power (PP) were measured during jump squats (JS) unloaded and loaded. In addition, the first base (1B) and the second base (2B) sprint performance, change of direction (505) on dominant (D) and nondominant (ND) sides, aerobic capacity, and muscle architecture characteristics of vastus lateralis (VL) including muscle thickness (MT), fascicle length (FL), and pennation angle (θp) were examined. The testing sessions occurred pre, mid, and post training (total 20 week pre- and in-season training period). Changes over time were analyzed by repeated-measures analysis of variance. The relationship between %change in muscle architecture variables and strength, speed, and change of direction variables from pre to post were assessed by Pearson product-moment correlation coefficient. Significant improvements in PV and PP occurred at all JS loads pre- to mid-testing and pre- to post-testing. Significant increases occurred pre-post in absolute 1RM, relative 1RM, 505 ND, and 2B sprint. The strongest relationships were found between %change in VL MT and 1B sprint (r = -0.80, p = 0.06), %change in VL FL and 2B sprint (r = -0.835, p = 0.02), and %change in relative 1RM and 505 D (r = -0.70, p = 0.04). In conclusion, gains in strength, power, and performance can occur during the season in elite softball players who are also engaged in a periodized RT program. Furthermore, changes in performance measures are associated with changes in muscle architecture.

Effects of dynamic resistance training on fascicle lengthand isometric strength

The aims of this study were to assess changes in muscle architecture, isometric and dynamic strength of the leg extensor muscles, resulting from dynamic resistance training, and the relationships between strength and muscle architecture variables. The participants (n = 30) were randomly assigned to one of two groups. The training group (n = 16; age 21.8 ± 2.3 years, body mass 74.8 ± 9.2 kg, height 1.75 ± 0.08 m) performed dynamic resistance training for 13 weeks. The control group (n = 14; age 19.9 ± 1.5 years, body mass 74.0 ± 8.5 kg, height 1.76 ± 0.05 m) did not perform any resistance training. Maximal dynamic and isometric strength were tested in both groups, before and after the training period. The members of the training group used the free-weight squat lift (90°) as their training exercise. The concentric phase of the squat was performed explosively. Skeletal muscle architecture of the vastus lateralis was visualized using ultrasonography. At the end of the study, significant increases in vastus lateralis muscle thickness (+6.9%, P < 0.001), fascicle length (+10.3%, P < 0.05), one-repetition maximum (+8.2%, P < 0.05), rate of force development (+23.8%, P < 0.05) and average force produced in the first 500 ms (+11.7%, P < 0.05) were seen only in the training group. Adaptations to the muscle architecture in the training group limited the loss of fibre force, and improved the capacity for developing higher velocities of contraction. The architectural changes in the training group were similar to those seen in studies where high-speed training was performed. In conclusion, dynamic resistance training with light loads leads to increases in muscle thickness and fascicle length, which might be related to a more efficient transmission of fibre force to the tendon.