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.

Isokinetic Strength After ACL Reconstruction: Influence of Concomitant Anterolateral Ligament Reconstruction

2021 ◽  
pp. 194173812110054
Author(s):  
Benoit Gillet ◽  
Yoann Blache ◽  
Isabelle Rogowski ◽  
Grégory Vigne ◽  
Bertrand Sonnery-Cottet ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Ligament Reconstruction ◽  
Knee Extensor ◽  
Anterolateral Ligament ◽  
Flexor Muscle ◽  
Knee Flexor ◽  
Strength Recovery ◽  
Flexor Muscles ◽  
Knee Muscle ◽  
Knee Muscle Strength

Background: To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively. Hypothesis: The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively. Study Design: Retrospective cohort study. Level of Evidence: Level 2. Methods: A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping. Results: Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups. Conclusion: The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively. Clinical Relevance: Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR.

Hamstring Flexibility Is Not Correlated with Isokinetic Knee Muscle Strength in Female Modern Dancers

2018 ◽  
Vol 33 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Ani Agopyan
Keyword(s):  
Muscle Strength ◽  
Knee Extensor ◽  
Peak Torque ◽  
Flexor Muscle ◽  
Work Production ◽  
University Level ◽  
Modern Dancers ◽  
Hamstring Flexibility ◽  
Knee Muscle ◽  
The Right

OBJECTIVE: To evaluate bilateral isokinetic knee extensor and flexor muscle strength relative to hamstring flexibility in female modern dancers. METHODS: 20 trained university-level female modern dance students (mean age 23.8±3.8 yrs) volunteered for the study. Concentric isokinetic peak torque (PT, in Nm), peak torque % of body weight (PT%BW, in Nm/kg), and total work (TW, in J) of the knee extensor and flexor muscles for each leg were measured with a dynamometer at a velocity of 60, 180, and 300°/s. Hamstring flexibility of both limbs was assessed by a goniometer with the subjects in a supine position using the active straight leg raise (SLR) test. Participants were divided into flexible (n=10) and highly flexible (n=10) groups based on their hamstring flexibility. RESULTS: The flexible and highly flexible groups had significant differences (p≤0.05) for the right (flexible, 119.7±4.3°; highly flexible, 137.7±2.6°) and left active SLR tests (flexible, 120.6±5.3°; highly flexible, 138.3±4.5°). No significant differences were found between the flexible and highly flexible dancers for concentric knee extensor and flexor muscle strength in all selected parameters (p≤0.05). There were also no significant correlations between flexibility and bilateral PT, PT%BW, and TW scores (60, 180, and 300°/s) of dancers at the concentric contraction (p≤0.05). CONCLUSION: These findings indicate that hamstring flexibility (for both the flexible and highly flexible groups) is not correlated with knee strength and has no impact on torque and work production during maximal concentric isokinetic knee muscle action in university-level female modern dancers.

Achilles Tendon Moment Arms Computed Using Ultrasound and Motion Analysis: In Vivo Estimates for Male Subjects

2008 ◽  
Author(s):  
Justin D. Cowder ◽  
Thomas S. Buchanan ◽  
Kurt T. Manal
Keyword(s):  
Achilles Tendon ◽  
Motion Capture ◽  
Hybrid Method ◽  
Lower Limb ◽  
Muscle Force ◽  
Average Weight ◽  
Moment Arm ◽  
Moment Arms ◽  
Male Subjects

Accurate estimates for Achilles tendon moment arm (MA) are essential when computing gastroc-soleus force from the net plantarflexion moment. Errors in approximating the Achilles tendon MA will adversely affect the muscle force estimate. We have noted that Achilles tendon MAs reported by Maganaris [1] and others are significantly greater (> 1 cm) than values used by Delp et al. computed using SIMM [2]. It is important to note that the stature of Delp’s lower limb model was almost identical to the average weight and height of the subjects in a study by Maganaris. This led us to question which MA profiles were more anatomically meaningful. To address this, we calculated Achilles tendon MAs for 10 male subjects using a previously described method. The method combines ultrasound and video-based motion capture, and referred to as the hybrid method. Subjects in our study were chosen to ensure they were of a similar stature to those tested by Maganaris, thereby minimizing confounding effects of subject anthropometrics.

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 Effect of long-term training adaptation on isokinetic strength in college male volleyball players

2019 ◽  
Vol 23 (5) ◽  
pp. 236-241
Author(s):  
A. Kafkas ◽  
M.E. Kafkas ◽  
S. Savaş
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Knee Extensor ◽  
Isokinetic Strength ◽  
Flexor Muscle ◽  
Knee Strength ◽  
Volleyball Players ◽  
Angular Velocities ◽  
Knee Muscle ◽  
Flexor Strength

Background and Study Aim: Most of this study focused on endurance, power, and anthropometric measurements but no research declared isokinetic strength changes during two years. The purpose of this study was to assess the effect of resistance exercises on two seasonal alters in isokinetic strength of knee muscles at different angular velocities, in college volleyball players. Material and Methods: Thirteen college volleyball players, (age: 21.75 years, body mass: 78.60 kg, and height: 187.0 cm) participated in the study. All college volleyball players take part in the two-year (8 month each year) volleyball-specific training and competitions. The measurement of peak isokinetic concentric knee extension and knee flexion torque in both legs were taken at 2 angular velocities of movement, low at 60° s-1, and intermediate at 180° s-1. Results: The pre- and post-test values of the peak isokinetic strength found that statistical significance difference, at 60° s-1 and 180° s-1 for knee extensor-flexor both dominant and non-dominant in favor of post-tests. Significant enhances were observed in the baseline dominant knee extensor-flexor muscle strength (extensor knee strength 60° s-1: 19.0%, 180° s-1: 20.5%, flexor knee strength, 60° s-1: 33.4%, 180° s-1: 31.4%) respectively. Non-dominant knee extensor-flexor muscle strength increased significantly over the two-year period (extensor knee strength 60° s-1: 21.3%, 180° s-1: 23.0%, flexor knee strength, 60° s-1: 37.4%, 180° s-1: 33.9%) respectively. Conclusion: As a result, our data suggests that the two-year planned program of specific volleyball and resistance training can increase the knee muscle extensor-flexor strength and H:Q ratios of volleyball players. Especially, at a 60° s-1 and 180° s-1 angular velocities, whilst the knee muscle extensor-flexor strength and H:Q ratios for dominant and non-dominant legs were increasing, also H:Q ratios disproportion were decreasing. Therefore, these alters indicated that regular specific-volleyball and resistance training can increase knee muscle extensor-flexor strength and H:Q ratios for dominant and non-dominant legs.

Development of a Computational Model to Study Effects of Rotator Cuff Tear Size and Location on Muscle Moment Arms

2007 ◽  
Author(s):  
Corinne R. Adams ◽  
Mark A. Baldwin ◽  
Peter J. Laz ◽  
Paul J. Rullkoetter ◽  
Joseph E. Langenderfer
Keyword(s):  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Muscle Fiber ◽  
Joint Strength ◽  
Muscle Force ◽  
Fatty Infiltration ◽  
Moment Arm ◽  
Moment Arms ◽  
Cuff Tear ◽  
Tear Size

Rotator cuff tendon tear causes alterations to cuff muscle architecture and tendons including muscle fascicle contracture and increased tendon length, fatty infiltration of the muscle fibers, muscle fiber pennation angle changes, asymmetric muscle atrophy, and altered muscle fiber type composition, e.g. [1]. These changes ultimately result in a reduction in muscle force, and frequently lead to a reduction of shoulder strength and a loss of functionality. Recently, division of the cuff tendons in a manner related to cuff tear has been shown to alter tendon excursions and cause muscle moment arms reductions in a cadaver experiment [2] and a computational study [3]. Evaluations of the effects of cuff tear size and location on cuff muscle moment arms have not been conducted. Consequently, the mechanisms by which the muscle force and moment arm changes affect joint strength are not well understood. An improved understanding of these relationships would increase potential for rehabilitation of joint strength following cuff repair. Models for evaluating rotator cuff tear are non-existent since subject-specific models have focused on healthy normal shoulders. Consequently, models have not been used to quantify the effects of clinically observed changes in muscle and tendon architecture on muscle moment arm and force generating capacity.

Comparison of Skull Shape in Marsupial and Placental Carnivores

1986 ◽  
Vol 34 (2) ◽  
pp. 109 ◽  
Author(s):  
L Werdelin
Keyword(s):  
Canis Lupus ◽  
Muscle Force ◽  
Red Fox ◽  
Tasmanian Devil ◽  
Moment Arm ◽  
Muscle Attachment ◽  
Temporal Fossa ◽  
Skull Shape ◽  
Moment Arms ◽  
Large Muscle

A set of 11 measurements on 40 species of placental (Order Carnivora) and marsupial (Order Dasyurida) carnivores is analysed by means of correspondence analysis. Dasyurida have long mandibles and tooth rows, large muscle attachment areas on the mandible, long moment arms of the temporalis and masseter, and a low occiput and short temporal fossa. Skull shape is uniform in Dasyurida, with about the same variability as in a family of Carnivora. The temporalis of Dasyurida is relatively small, but this may be compensated for by the more rounded shape and longer moment arm. The Tasmanian tiger, Thylacinus cynocephalus, is more similar in skull shape to the red fox, Vulpes vulpes, than to the placental wolf, Canis lupus. The M5 of Dasyurida occupies the same geometric position as the MI in Carnivora, providing a possible explanation for the greater variability in cheek teeth in Carnivora. The Tasmanian devil, Sarcophilus harrisii, is similar to the Hyaenidae in having a shorter distance between the ultimate sectorial molar and the condyle. It is suggested that this is an adaptation to cracking open bones, as this mandible geometry brings the main bone-cracking teeth closer to the region of greatest muscle force.

Effect of Curvature on Sagittal Plane Moment Arms of Human Neck Muscles

2013 ◽  
Author(s):  
Bethany L. Suderman ◽  
Anita N. Vasavada
Keyword(s):  
Soft Tissues ◽  
Sagittal Plane ◽  
Neck Muscle ◽  
Moment Arm ◽  
Moment Arms ◽  
Musculoskeletal Models ◽  
Flexion Extension ◽  
Neck Rotation ◽  
Curved Paths

In musculoskeletal models of the cervical spine, muscles are often modeled as straight paths from origin to insertion [ e.g., 1]. However, muscle paths in the neck are constrained by bone and other soft tissues, and some studies have found that applying curvature to muscle paths improves anatomical accuracy [2; 3] and affects muscle parameters such as moment arm [3] and moment [4]. Currently, data available in the literature for neck muscle moment arms (MA) are sparse. In this study we estimated in-vivo moment arms using MRI-derived neck muscle paths modeled with curvature and those modeled as straight paths, for head and neck rotation in the sagittal plane (flexion-extension motion). We hypothesize that moment arm estimates for curved paths will be significantly different from estimates for straight paths.

scholarly journals Knee extension moment arm variations relate to mechanical function in walking and running

2021 ◽  
Vol 18 (181) ◽  
pp. 20210326
Author(s):  
Mitchell G. A. Wheatley ◽  
Darryl G. Thelen ◽  
Kevin J. Deluzio ◽  
Michael J. Rainbow
Keyword(s):  
Rotation Axis ◽  
Knee Extensor ◽  
Knee Extension ◽  
Plane Motion ◽  
Moment Arm ◽  
Motion Direction ◽  
Moment Arms ◽  
Tibiofemoral Rotation ◽  
Out Of Plane ◽  
The Moment

The patellofemoral joint plays a crucial mechanical role during walking and running. It increases the knee extensor mechanism's moment arm and reduces the knee extension muscle forces required to generate the extension moment that supports body weight, prevents knee buckling and propels the centre of mass. However, the mechanical implications of moment arm variation caused by patellofemoral and tibiofemoral motion remain unclear. We used a data-driven musculoskeletal model with a 12-degree-of-freedom knee to simulate the knee extension moment arm during walking and running. Using a geometric method to calculate the moment arm, we found smaller moment arms during running than during walking in the swing phase. Overall, knee flexion causes differences between running and walking moment arms as increased flexion causes a posterior shift in the tibiofemoral rotation axis and patella articulation with the distal femur. Moment arms were also affected by knee motion direction and best predicted by separating by direction instead of across the entire gait cycle. Furthermore, we found high inter-subject variation in the moment arm that was largely explained by out-of-plane motion. Our results are consistent with the concept that shorter moment arms increase the effective mechanical advantage of the knee and may contribute to increased running velocity.

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