Tendon elongation influences the amplitude of interpolated doublets in the assessment of activation in elderly men

2005 ◽  
Vol 98 (1) ◽  
pp. 221-226 ◽  
Author(s):  
Christopher I. Morse ◽  
Jeanette M. Thom ◽  
Karen M. Birch ◽  
Marco V. Narici
Keyword(s):  
Ankle Joint ◽  
Joint Angle ◽  
Plantar Flexion ◽  
Negative Association ◽  
Plantar Flexors ◽  
Joint Angles ◽  
Elderly Men ◽  
Electromechanical Delay ◽  
Tendon Elongation ◽  
Voluntary Contractions

This study investigated the influence of tendon elongation (TE) on postcontraction doublet (PCD) torque in the assessment of activation in the plantar flexors of nine elderly men (EM, age 73.7 ± 3.6 yr) and nine young men (YM, age 24.7 ± 4.7 yr). Plantar flexion maximal voluntary contractions (MVC) and activation were assessed at ankle joint angles of −20° (dorsiflexion), 0°, and 20° (plantar flexion). Across the ankle joint angles tested, compared with YM, the EM had a 36–49% lower plantar flexion MVC ( P < 0.01), TE was greater by 25–31% ( P < 0.01), and electromechanical delay was 65–108% greater ( P < 0.01). Activation (PCD torque to interpolated doublet torque) was 15% lower in EM compared with YM at −20° ( P < 0.05), but no different at 0 and 20°. In the EM, PCD torque relative to MVC torque was significantly lower at 20° compared with 0° ( P < 0.05). Electromechanical delay was positively correlated with TE ( R2 = 0.489, P < 0.01). In conclusion, this investigation demonstrates that, although a negative association exists between TE and PCD torque, the consequence of a greater TE on the estimation of activation in EM is negligible. This is due to a greater influence of ankle joint angle on the occlusion of a superimposed doublet, which counteracts the lesser influence of joint angle on TE and PCD torque. However, a greater TE in EM was found to significantly increase electromechanical delay, which is expected to influence the time needed for postural readjustments.

scholarly journals Influence of tendon slack on electromechanical delay in the human medial gastrocnemius in vivo

2004 ◽  
Vol 96 (2) ◽  
pp. 540-544 ◽  
Author(s):  
Tetsuro Muraoka ◽  
Tadashi Muramatsu ◽  
Tetsuo Fukunaga ◽  
Hiroaki Kanehisa
Keyword(s):  
Electrical Stimulation ◽  
Ankle Joint ◽  
Joint Angle ◽  
Joint Torque ◽  
Medial Gastrocnemius ◽  
Joint Angles ◽  
Electromechanical Delay ◽  
Tendon Length ◽  
Slack Length

The purpose of this study was to clarify the influence of muscle-tendon complex stretch on electromechanical delay (EMD) in terms of the extent of tendon slack in the human medial gastrocnemius (MG). EMD and MG tendon length were measured at each of five ankle joint angles (-30, -20, -10, 0, and 5°: positive values for dorsiflexion) using percutaneous electrical stimulation and ultrasonography, respectively. The extent of MG tendon slack was calculated as MG tendon length shortening, standardized with MG tendon slack length obtained at the joint angle (-16° ± 5°) where the passive ankle joint torque was zero. EMD at -30° (19.2 ±2.2 ms) and -20° (17.2 ± 1.3 ms) was significantly greater than that at -10° (16.0 ±2.3 ms), 0° (15.0 ±1.4 ms), and 5° (14.8 ±1.4 ms), and at 0 and 5°, respectively. The relative EMD, normalized with the maximal EMD for each subject, decreased dependent on the extent of decrease in MG tendon slack. There were no significant differences in EMD among the joint angles (-10, 0, and 5°) where MG tendon slack was taken up. These results suggest that the extent of tendon slack is an important factor for determining EMD.

Tendinous movement of a human muscle during voluntary contractions determined by real-time ultrasonography

1996 ◽  
Vol 81 (3) ◽  
pp. 1430-1433 ◽  
Author(s):  
T. Fukunaga ◽  
M. Ito ◽  
Y. Ichinose ◽  
S. Kuno ◽  
Y. Kawakami ◽  
...  
Keyword(s):  
Real Time ◽  
Ankle Joint ◽  
Plantar Flexion ◽  
Tibialis Anterior Muscle ◽  
Human Muscle ◽  
Muscle Physiology ◽  
Angular Change ◽  
Potential Applications ◽  
Voluntary Contractions ◽  
Real Time Ultrasonography

The degree of shortening or lengthening of muscles during joint actions has not been clarified in humans, although such information is essential in understanding human muscle functions. In this study, the tendinous movement of a muscle was determined by real-time ultrasonography during voluntary contractions. The tibialis anterior muscle (TA) was tested in five healthy men who performed dorsi- and plantar flexion movements (shortening and lengthening of TA) at two frequencies (0.1 and 1.5 Hz). The insertion point (eta) of fascicles onto the aponeurosis was clearly visualized on the ultrasonogram, and its position relative to a fixed marker moved proximally and distally according to dorsi- and plantar flexion of ankle joint. The movement of eta occurred in phase with the angular change of ankle joint, giving high correlations (r = 0.93 to 0.97) between the displacement of eta and the angle. The displacement of eta for one radian of joint angle change, 46.5 +/- 1.7 (SD) mm, was comparable to the reported moment arm of TA. The present method has many potential applications in the field of muscle physiology and biomechanics in humans.

Mechanical and electromyographic analysis of reciprocal inhibition at the human ankle joint

1995 ◽  
Vol 74 (2) ◽  
pp. 849-855 ◽  
Author(s):  
T. Sinkjaer ◽  
J. Nielsen ◽  
E. Toft
Keyword(s):  
Ankle Joint ◽  
Stretch Reflex ◽  
Plantar Flexion ◽  
Joint Stiffness ◽  
Common Peroneal Nerve ◽  
Reciprocal Inhibition ◽  
Mechanical Effect ◽  
Voluntary Contraction ◽  
Plantar Flexors ◽  
Before And After

1. The purpose of the present study is to investigate how reciprocal inhibition influences the mechanical and electromyographic (EMG) properties of the ankle plantar flexors in humans during a voluntary contraction. 2. At different levels of maintained plantar flexion contractions ranging from 0 to 20 Nm, the size of the soleus EMG stretch reflex and the ankle joint stiffness (ration between the torque increment and the amplitude of the stretch) were measured in response to an imposed dorsiflexion. At matched plantar flexion contraction levels, stretch responses were compared before and after reversible block of the common peroneal nerve (CPN). Stretch responses were also measured during an attempted voluntary fictive dorsiflexion after CPN block. 3. In the preactivated soleus muscles, the phasic EMG response to stretch consisted of two peaks labeled M1 and M2. After CPN block, the M1 short-latency stretch reflex on average increased by 25 +/- 5.7%, mean +/- SD (P < 0.001), and the M2 stretch reflex increased on average by 29 +/- 13.0% (P = 0.002). 4. The total stiffness of the ankle joint during a stretch is the sum of the nonreflex and the reflex mediated stiffness. The total stiffness after CPN block increased on average by 13 +/- 2.7% (P = 0.002) and the estimated reflex stiffness by 33 +/- 6.5% (P < 0.001). 5. When the subjects were asked to make a strong dorsiflexion after CPN block, the soleus stretch reflex was depressed to the extent that the reflex mediated mechanical effect around the ankle joint was abolished.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Heel Construction on Muscular Control Potential of the Ankle Joint in Running

2013 ◽  
Vol 29 (6) ◽  
pp. 740-748 ◽  
Author(s):  
Steffen Willwacher ◽  
Wolfgang Potthast ◽  
Markus Konrad ◽  
Gert-Peter Brüggemann
Keyword(s):  
Ankle Joint ◽  
Unit Length ◽  
Plantar Flexion ◽  
Reaction Force ◽  
Joint Moment ◽  
Triceps Surae ◽  
Heel Strike ◽  
Joint Mechanics ◽  
Plantar Flexors ◽  
Joint Moments

The purpose of this study was to investigate the effect of heel construction on ankle joint mechanics during the early stance phase of running. Kinematic and kinetic parameters (ankle joint angles, angular velocities and joint moments, lever arms of ground reaction force, triceps surae muscle tendon unit lengths, and rates of muscle tendon unit length change) were calculated from 19 male subjects running at 3.3 m/s in shoes with different heel constructions. Increasing heel height and posterior wedging amplified initial plantar flexion velocity and range. The potential for a muscle to control the movement of a joint depends upon its ability to produce joint moments. Runners in this study showed decreased external eversion moments and an increase in eversion range. Maximum eversion angles were not significantly affected by shoe conditions. Without considerable tendon prestretch, joint moment generation potentials of triceps surae and deep plantar flexors might be inhibited due to rapid plantar flexion based on the force–velocity relationship. It could be speculated that increasing ankle inversion at heel strike could be a strategy to keep maximum eversion angles inside an adequate range, if joint moment generation potentials of deep plantar flexors are inhibited due to rapid plantar flexion.

How the ankle joint angle alters the antagonist and agonist torques during maximal efforts in dorsi- and plantar flexion

2011 ◽  
Vol 21 (6) ◽  
pp. e273-e281 ◽  
Author(s):  
M. Billot ◽  
E. M. Simoneau ◽  
Y. Ballay ◽  
J. Van Hoecke ◽  
A. Martin
Keyword(s):  
Ankle Joint ◽  
Joint Angle ◽  
Plantar Flexion

The Effect of Ankle Bracing and Taping on Joint Position Sense in the Stable Ankle

1996 ◽  
Vol 5 (3) ◽  
pp. 206-213 ◽  
Author(s):  
Eric J. Heit ◽  
Scott M. Lephart ◽  
Susan L. Rozzi
Keyword(s):  
Ankle Joint ◽  
Joint Angle ◽  
Plantar Flexion ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Significant Difference ◽  
And Control ◽  
Flexion Test ◽  
Ankle Bracing

The purpose of this study was to determine the proprioceptive effects of ankle bracing and taping. Proprioception was assessed in 26 subjects by evaluating ankle joint position sense, which was determined by the subjects' ability to actively reproduce a passively positioned joint angle. Testing was performed at positions of 30° of plantar flexion and 15° of inversion. Each subject underwent four trials at each test angle under three conditions: braced, taped, and control. For the plantar flexion test, both the braced condition and the taped condition significantly enhanced joint position sense when compared to the control condition. There was no significant difference between the braced and taped conditions. For the inversion test, the taped condition significantly enhanced joint position sense compared to the control condition. There was no significant difference between the braced and the control conditions or between the braced and the taped conditions. This study demonstrates that ankle bracing and taping improve joint position sense in the stable ankle.

scholarly journals The effects of passive stretching plus vibration on strength and activation of the plantar flexors

2016 ◽  
Vol 41 (9) ◽  
pp. 917-923 ◽  
Author(s):  
Jonathan D. Miller ◽  
Trent J. Herda ◽  
Michael A. Trevino ◽  
Eric M. Mosier
Keyword(s):  
Plantar Flexion ◽  
Muscle Length ◽  
Peak Torque ◽  
Plantar Flexors ◽  
Cohen’S D ◽  
Passive Stretching ◽  
Before And After ◽  
Cohen's D ◽  
Voluntary Contractions ◽  
Musculotendinous Stiffness

This study examined the effects of passive stretching only (PS+CON) and passive stretching with the addition of continuous vibration (VIB) during post-passive stretching tests (PS+VIB) on peak torque (PT), percent voluntary inactivation (%VI), single stimulus twitch torque (TTSINGLE), and doublet stimuli twitch torque (TTDOUBLET) of the plantar flexors at a short (20° plantar flexion (PF)) and long muscle length (15° dorsiflexion (DF)). Fourteen healthy men (age = 22 ± 3 years) performed isometric maximal voluntary contractions at PF and DF, and passive range of motion (PROM) assessments before and after 8 × 30-s passive stretches without (PS+CON) or with VIB (PS+VIB) administered continuously throughout post-passive stretching tests. The passive properties of the muscle tendon unit were assessed pre- and post-passive stretching via PROM, passive torque (PASSTQ), and musculotendinous stiffness (MTS) measurements. PT, TTSINGLE, and TTDOUBLET decreased, whereas, %VI increased following passive stretching at PF and DF (P < 0.05) with no significant differences between PS+CON and PS+VIB. PASSTQ and MTS decreased while PROM increased post-passive stretching during both trials (P < 0.05). The stretching-induced force/torque deficit and increases in %VI were evident following passive stretching at short and long muscle lengths. Although not statistically significant, effect size calculations suggested large and moderate differences in the absolute changes in PT (Cohen’s d = 1.14) and %VI (Cohen’s d = 0.54) from pre- to post-passive stretching between treatments, with PS+VIB having greater decreases of PT and higher %VI than PS+CON. The decrement in PT following passive stretching may be primarily neural in origin.

The Dynamics of Postural Sway Cannot Be Captured Using a One-Segment Inverted Pendulum Model: A PCA on Segment Rotations During Unperturbed Stance

2008 ◽  
Vol 100 (6) ◽  
pp. 3197-3208 ◽  
Author(s):  
Ilona J. Pinter ◽  
Roos van Swigchem ◽  
A. J. Knoek van Soest ◽  
Leonard A. Rozendaal
Keyword(s):  
Postural Control ◽  
Ankle Joint ◽  
Inverted Pendulum ◽  
Joint Angle ◽  
Postural Sway ◽  
Lower Leg ◽  
Joint Angles ◽  
Inverted Pendulum Model ◽  
Pendulum Model ◽  
Ankle Angle

Research on unperturbed stance is largely based on a one-segment inverted pendulum model. Recently, an increasing number of studies report a contribution of other major joints to postural control. Therefore this study evaluates whether the conclusions originating from the research based on a one-segment model adequately capture postural sway during unperturbed stance. High-pass filtered kinematic data (cutoff frequency 1/30 Hz) obtained over 3 min of unperturbed stance were analyzed in different ways. Variance of joint angles was analyzed. Principal-component analysis (PCA) was performed on the variance of lower leg, upper leg, and head–arms–trunk (HAT) angles, as well as on lower leg and COM angle (the orientation of the line from ankle joint to center of mass). It was found that the variance in knee and hip joint angles did not differ from the variance found in the ankle angle. The first PCA component indicated that, generally, the upper leg and HAT segments move in the same direction as the lower leg with a somewhat larger amplitude. The first PCA component relating ankle angle variance and COM angle variance indicated that the ankle joint angle displacement gives a good estimate of the COM angle displacement. The second PCA component on the segment angles partly explains the apparent discrepancy between these findings because this component points to a countermovement of the HAT relative to the ankle joint angle. It is concluded that postural control during unperturbed stance should be analyzed in terms of a multiple inverted pendulum model.

scholarly journals Research on Joint-Angle Prediction Based on Artificial Neural Network for Above-Knee Amputees

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7199
Author(s):  
Jianyu Yang ◽  
Guanchao Li ◽  
Xiaofei Zhao ◽  
Hualong Xie
Keyword(s):  
Neural Network ◽  
Ankle Joint ◽  
Lower Limb ◽  
Plantar Pressure ◽  
Joint Angle ◽  
Golden Section ◽  
Prediction Method ◽  
Maximum Error ◽  
Generalized Regression Neural Network ◽  
Joint Angles

In the current study, our research group proposed an asymmetric lower extremity exoskeleton to enable above-knee amputees to walk with a load. Due to the absence of shank and foot, the knee and ankle joint at the amputation side of the exoskeleton lack tracking targets, so it is difficult to realize the function of assisted walking when going up and downstairs. Currently, the use of lower-limb electromyography to predict the angles of lower limb joints has achieved remarkable results. However, the prediction effect was poor when only using electromyography from the thigh. Therefore, this paper introduces hip-angle and plantar pressure signals for improving prediction effect and puts forward a joint prediction method of knee- and ankle-joint angles by electromyography of the thigh, hip-joint angle, and plantar pressure signals. The generalized regression neural network optimized by the golden section method is used to predict the joint angles. Finally, the parameters (the maximum error, the Root-Mean-Square error (RMSE), and correlation coefficient (γ)) were calculated to verify the feasibility of the prediction method.

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