- Email: [email protected]
Properties of tendinous structures of rat EDL muscle-tendon complex
1008
Abstracts-International Societyof HiomechanicsXII (‘ongrc\\
I~JXO
DETERNINATION OF THE COMPOSITE AND INDIVIDUAL JOINT SINUS CONES OF THE HUMAN SHOULDER coNF%Ex A.E. Engin S.T. TUmer Professor Assistant Professor Department of Engineering Mechanics Mechanical Engineering Department The Ohio State University King Saud University Columbus, Ohio, 43210, U.S.A. Riyadh 11421, K.S.A. In this paper the statistical in-vivo data base recently established by Engin and Chen is utilized to determine quantitatively first the five parameters of an elliptical composite joint sinus cone, and second the fifteen parameters of the individual joint sinus cones associated with the sternoclavicular, claviscapular, and glenohumeral joints of the human shoulder complex by introducing the "minimum joint motions" criterion. To achieve these tasks two different optimization techniques, namely the flexible tolerance method and the Lagrange multipliers method are utilized. The effectiveness of both methods is tested and the numerical results for the orientations and the sizes of various joint sinus cones are presented.
QUANTIFICATION OF NEUROMUSCULAR-PROPAGATION FAILURE IN SINGLE MOTOR UNITS OF CATS DURING A FATIGUE TEST R.M. Enoka, Y. Laouris, R.M. Reinking, N. Trayanova, L. Bevan and D.G. Stuart Department of Physiology, University of Arizona, Tucson, AZ 85724, USA. The unitary EMG that is elicited by stimulation of a small bundle of axons, part of a muscle nerve, or the whole muscle nerve, is often used to test for the failure of neuromuscularpropagation. The purpose of this study was to determine whether it is necessaryto describechangesin the evoked EMG by measurementof EMG area, or whether the measurement of EMG amplitude is sufficient. In deeply anesthetizedadult cats, functionally isolated motor units in the hindlimb muscle, tibialis posterior, were subjectedto a fatigue regimen that comprised 330-ms trains of 13 stimuli (40 Hz), delivered once each second for 360 s. The EMG, which representsthe compound muscle action potential from severalmuscle fibers of single motor units, was characterizedby the measurement of amplitude (a), duration (d), area (A) and a coefficient of proportionality (k) that related area to the product of amplitude and duration: A=kad. A constant coefficient of proportionality during the fatigue test would suggestthat area is not an independent parameter but, rather, is proportional to the product of amplitude and duration. The degree of change in EMG varied with the fatigability of the motor unit; the most fatigable motor units had the greatest declinesin amplitude and area and the greatestincreasesin duration. Although most fatigable units also had the greatestincreasein k, the variability was so great that the change in k was not significant. This observation led us to conclude that k, the coefftcient of roportionality, was constant during the presently used fatigue test and that the EMG could have been adequateYy representedby the measureof amplitude. Supported by USPHS grants NS 20544, NS 07039, HL 07249 and NSF grant INT 8520863.
PROPERTIES OF TENDINOUS STRUCTURES OF RAT EDL MUSCLE-TENDON COMPLEX Gertjan J.C. Ettema and Peter A. Huijing Vakgroep Functionele Anatomie, Faculteit Bewegingswetenschappen, Vrije Universiteit Amsterdam, v.d. Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. Compliance of the series elastic component (SEC) of rat EDL muscle-tendon complex (n=5) was determined using quick length decreases during isometric tetanic contractions at different muscle lengths. Length changes of the were measured using photography. tendinous structures, i.e. tendon and aponeurosis, During a contraction at muscle optimum length extension of the aponeurosis and tendon The length difference between amounted to 2.3 + 0.6 '% and 3.1 + 1.0 $ respectively. aponeurosis in active muscle at near-slack length and optimum length amounted to extension of the entire SEC calculated for the more than 2 mm (10 %), and exceeded for passive and active muscle two different length-force same force range. Furthermore, relationships of the aponeurosis were found. It is concluded that, in isometric contractions, aponeurosis length is not only force dependent but also influenced by muscle length, which causes a shift in the force-length relationship of the aponeurosis over the length axis. This muscle length dependence does not occur for the tendon.
Abstracts-International Societyof HiomechanicsXII (‘ongrc\\
I~JXO
DETERNINATION OF THE COMPOSITE AND INDIVIDUAL JOINT SINUS CONES OF THE HUMAN SHOULDER coNF%Ex A.E. Engin S.T. TUmer Professor Assistant Professor Department of Engineering Mechanics Mechanical Engineering Department The Ohio State University King Saud University Columbus, Ohio, 43210, U.S.A. Riyadh 11421, K.S.A. In this paper the statistical in-vivo data base recently established by Engin and Chen is utilized to determine quantitatively first the five parameters of an elliptical composite joint sinus cone, and second the fifteen parameters of the individual joint sinus cones associated with the sternoclavicular, claviscapular, and glenohumeral joints of the human shoulder complex by introducing the "minimum joint motions" criterion. To achieve these tasks two different optimization techniques, namely the flexible tolerance method and the Lagrange multipliers method are utilized. The effectiveness of both methods is tested and the numerical results for the orientations and the sizes of various joint sinus cones are presented.
QUANTIFICATION OF NEUROMUSCULAR-PROPAGATION FAILURE IN SINGLE MOTOR UNITS OF CATS DURING A FATIGUE TEST R.M. Enoka, Y. Laouris, R.M. Reinking, N. Trayanova, L. Bevan and D.G. Stuart Department of Physiology, University of Arizona, Tucson, AZ 85724, USA. The unitary EMG that is elicited by stimulation of a small bundle of axons, part of a muscle nerve, or the whole muscle nerve, is often used to test for the failure of neuromuscularpropagation. The purpose of this study was to determine whether it is necessaryto describechangesin the evoked EMG by measurementof EMG area, or whether the measurement of EMG amplitude is sufficient. In deeply anesthetizedadult cats, functionally isolated motor units in the hindlimb muscle, tibialis posterior, were subjectedto a fatigue regimen that comprised 330-ms trains of 13 stimuli (40 Hz), delivered once each second for 360 s. The EMG, which representsthe compound muscle action potential from severalmuscle fibers of single motor units, was characterizedby the measurement of amplitude (a), duration (d), area (A) and a coefficient of proportionality (k) that related area to the product of amplitude and duration: A=kad. A constant coefficient of proportionality during the fatigue test would suggestthat area is not an independent parameter but, rather, is proportional to the product of amplitude and duration. The degree of change in EMG varied with the fatigability of the motor unit; the most fatigable motor units had the greatest declinesin amplitude and area and the greatestincreasesin duration. Although most fatigable units also had the greatestincreasein k, the variability was so great that the change in k was not significant. This observation led us to conclude that k, the coefftcient of roportionality, was constant during the presently used fatigue test and that the EMG could have been adequateYy representedby the measureof amplitude. Supported by USPHS grants NS 20544, NS 07039, HL 07249 and NSF grant INT 8520863.
PROPERTIES OF TENDINOUS STRUCTURES OF RAT EDL MUSCLE-TENDON COMPLEX Gertjan J.C. Ettema and Peter A. Huijing Vakgroep Functionele Anatomie, Faculteit Bewegingswetenschappen, Vrije Universiteit Amsterdam, v.d. Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. Compliance of the series elastic component (SEC) of rat EDL muscle-tendon complex (n=5) was determined using quick length decreases during isometric tetanic contractions at different muscle lengths. Length changes of the were measured using photography. tendinous structures, i.e. tendon and aponeurosis, During a contraction at muscle optimum length extension of the aponeurosis and tendon The length difference between amounted to 2.3 + 0.6 '% and 3.1 + 1.0 $ respectively. aponeurosis in active muscle at near-slack length and optimum length amounted to extension of the entire SEC calculated for the more than 2 mm (10 %), and exceeded for passive and active muscle two different length-force same force range. Furthermore, relationships of the aponeurosis were found. It is concluded that, in isometric contractions, aponeurosis length is not only force dependent but also influenced by muscle length, which causes a shift in the force-length relationship of the aponeurosis over the length axis. This muscle length dependence does not occur for the tendon.