Imaging-based estimates of moment arm length in intact human muscle-tendons

Maganaris, Constantinos N.

doi:10.1007/s00421-003-1033-x

Cited by 99 publications

(113 citation statements)

References 39 publications

(50 reference statements)

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“…The current results reflecting performance capabilities at 25°, 35° and 45 ° of knee flexion demonstrated that greater flexion 255 was associated with superior quadriceps contractile force. Although subtle alterations in the extensor moment arm will have contributed to angle-specific performance [Maganaris et al, 2004], this finding is congruent with the predictions of the length-tension relationship [McComas, 1996] in which there is likely to be a more favourable degree of myofilament and contractile protein overlap at 45° than at 25° of knee flexion. Greater angles of knee flexion 260 also elicited superior (i.e.…”

Section: 4 Discussionsupporting

confidence: 73%

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Minshull

Rees²,

Gleeson

2011

Journal of Electromyography and Kinesiology

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This study examined the volitional and magnetically-evoked neuromuscular performance of the quadriceps femoris at functional knee joint angles adjacent to full extension. Indices of volitional and magnetically-evoked neuromuscular performance (N= 15 healthy males; 23.5 ± 2.9 years; 71.5 ± 5.4 kg; 176.5 ± 5.5 cm) were obtained at 25°; 35° and 45° of knee 30 flexion. Results showed that volitional and magnetically-evoked peak force (PF V ; PTFE, respectively) and electromechanical delay (EMD V ; EMD E , respectively) were enhanced by increased knee flexion. However, greater relative improvements in volitional compared to evoked indices of neuromuscular performance were observed with increasing flexion from 25° to 45° (e.g. EMD V ; EMD E : 36% vs. 11% improvement, respectively; F [2) i 4 ] = 6.8; p < 35 0.05). There were no significant correlations between EMD V and EMD E or PF V and PTF E , respectively at analogous joint positions. These findings suggest that the extent of the relative differential between volitional and evoked neuromuscular performance capabilities is joint angle-specific and not correlated with performance capabilities at adjacent angles, but tends to be smaller with increased flexion. As such, effective prediction of volitional 40 from evoked performance capabilities at both analogous and adjacent knee joint positions would lack robustness.

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Section: 4 Discussionsupporting

confidence: 73%

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Minshull

Rees²,

Gleeson

2011

Journal of Electromyography and Kinesiology

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“…Two well-defined anatomic points on the talus (A and B) were chosen. On the basis of the short distance between the points A and B, two straight lines were drawn subtending at a right angle 10 cm proximal to the talus (15,16). The shape of the tibia was then superimposed onto the image taken at the plantarflexed position (ankle angle of ϩ15°), and the shape of the talus was drawn onto the same transparency.…”

Section: Methodsmentioning

confidence: 99%

Direct comparison of in vivo Achilles tendon moment arms obtained from ultrasound and MR scans

Fath

Blazevich

Waugh

et al. 2010

Journal of Applied Physiology

121

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Accurate and reliable estimation of muscle moment arms is a prerequisite for the development of musculoskeletal models. Numerous techniques are available to estimate the Achilles tendon moment arm in vivo. The purposes of this study were 1) to compare in vivo Achilles tendon moment arms obtained using the center of rotation (COR) and tendon excursion (TE) methods and 2) to assess the reliability of each method. For the COR method, magnetic resonance (MR) images from nine participants were obtained at ankle angles of −15°, 0°, and +15° and analyzed using Reuleaux' method. For the TE method, the movement of the gastrocnemius medialis-Achilles tendon junction was recorded using ultrasonography as the ankle was passively rotated through its range of motion. The Achilles tendon moment arm was obtained by differentiation of tendon displacement with respect to ankle angular excursion using seven different differentiation techniques. Moment arms obtained using the COR method were significantly greater than those obtained using the TE method ( P < 0.01), but results from both methods were well correlated. The coefficient of determination between moment arms derived from the COR and TE methods was highest when tendon displacement was linearly differentiated over a ±10° interval ( R2 = 0.94). The between-measurement coefficient of variation was 3.9% for the COR method and 4.5–9.7% for the TE method, depending on the differentiation technique. The high reliabilities and strong relationship between methods demonstrate that both methods are robust against their limitations. The large absolute between-method differences (∼25–30%) in moment arms have significant implications for their use in musculoskeletal models.

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“…After a standardized warm-up (Fig. 1A), L MA was measured using the tendon excursion method (1,44 placed over the myotendinous junction of the gastrocnemius medialis.…”

Section: Measurement Of Biomechanical Featuresmentioning

confidence: 99%

In vivo maximal fascicle-shortening velocity during plantar flexion in humans

Hauraix

Nordez

Guilhem

et al. 2015

Journal of Applied Physiology

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Interindividual variability in performance of fast movements is commonly explained by a difference in maximal muscle-shortening velocity due to differences in the proportion of fast-twitch fibers. To provide a better understanding of the capacity to generate fast motion, this study aimed to 1) measure for the first time in vivo the maximal fascicle-shortening velocity of human muscle; 2) evaluate the relationship between angular velocity and fascicle-shortening velocity from low to maximal angular velocities; and 3) investigate the influence of musculo-articular features (moment arm, tendinous tissues stiffness, and muscle architecture) on maximal angular velocity. Ultrafast ultrasound images of the gastrocnemius medialis were obtained from 31 participants during maximal isokinetic and light-loaded plantar flexions. A strong linear relationship between fascicle-shortening velocity and angular velocity was reported for all subjects (mean R 2 ϭ 0.97). The maximal shortening velocity (V Fmax) obtained during the no-load condition (NLc) ranged between 18.8 and 43.3 cm/s. V Fmax values were very close to those of the maximal shortening velocity (V max), which was extrapolated from the F-V curve (the Hill model). Angular velocity reached during the NLc was significantly correlated with this V Fmax (r ϭ 0.57; P Ͻ 0.001). This finding was in agreement with assumptions about the role of muscle fiber type, whereas interindividual comparisons clearly support the fact that other parameters may also contribute to performance during fast movements. Nevertheless, none of the biomechanical features considered in the present study were found to be directly related to the highest angular velocity, highlighting the complexity of the upstream mechanics that lead to maximalvelocity muscle contraction. maximal unloaded velocity; muscle-tendon unit; muscle mechanics; muscle architecture; stiffness; ultrasound THE CAPACITY OF HUMAN SKELETAL muscle to achieve maximal power production is functionally very important during ballistic movements such as sprinting or jumping. The maximal angular velocity an individual can produce represents one of the key determinants of this ability and hence of human performance in various explosive tasks such as a sprint while running or cycling (31, 57). In the literature, this ability to reach extreme angular velocities in unloaded conditions is related mainly to a higher proportion of fast-twitch fibers (5, 11, 56) or a longer fascicle length, or both, which implies a higher number of sarcomeres in series (9, 53). These considerations suggest that subjects who are able to produce high velocity at the joint level should also be able to develop high muscle fascicle-shortening velocity. Consequently, the muscleshortening velocity should be a key determinant of the ability to perform very-high-velocity movements.To our knowledge, no previous study has measured actual maximal fascicle-shortening velocity in vivo in humans. Although measurement of fascicle-shortening velocity is classically performed using ul...

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Imaging-based estimates of moment arm length in intact human muscle-tendons

Cited by 99 publications

References 39 publications

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Joint angle affects volitional and magnetically-evoked neuromuscular performance differentially

Direct comparison of in vivo Achilles tendon moment arms obtained from ultrasound and MR scans

In vivo maximal fascicle-shortening velocity during plantar flexion in humans

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