Measurement of frog semitendinosus force, tendon load-deformation and load-strain properties

MEASUREMENTOF FROG SEMITENDINOSUS FORCE, TENDON LOAD-DEFORMATION AND LOAD-STRAIN PROPERTIES Richard L. Lieber and Marmot E. Leonard Division of Orthopaedic Surgery, Department of Sur ery University of California and V.A. Medical Center, San Diego San Diego, California 9216 9 INTRODUCTION AND METHODS: We previously modelled the relationship between semitendinosus (ST) sarcomere len th and hip and knee joint an le during hopping assuming zero tendon compliance Mai an % Lieber, J. Biomech. , in press 4 . In order to investigate the effect of tendon camp 1 iance we measured the load-deformation and load-strain properties of the frog ST tendon using a dual-mode motor and video dimensional analyzer. Deformation

(mm)

0.15 0.30 0.45 0.60

Load (N) .25 .61 .87 1.46

f t 2 +

Strain

.19 .50 .28 .26

(%) -__

Load (N) .I8 .37 .90 1.2

E 3:o 5.0

f ?: k t

% Po

.14 .29 .48 .44

l!oo 300 400

RESULTS AND DISCUSSION: The mean f SD of the measurements from three samples are the table. Maximum tetanic tension (PO for these samples averaged 0.3 f 0.05 N. tendon strain at PO would be less tha b 2%. These data suggest that, durin an contraction at optimal sarcomere len th, the muscle fiber shortens from ii .2 urn with tendon slack at 2.2 urn. In t F1. 1s particular case, muscle force would not be However, in other cases tendon compliance could effect ST force.

shown in Note that isometric to 2.0 urn altered.

EFFECTS OF SYNERGISTIC WRIST MOTION ON FLEXOR TENDON EXCURSION IN THE HAND Gau-Tyan Lin, Kai-Nan An, Peter C. Amadio, William P. Cooney, Ronald L. Linscheid, and Edmund Y.S. Chao Orthopedic Biomechanics Laboratory Mayo Clinic/Mayo Foundation, Rochester, Minnesota 55905 U.S.A. Based on biomechanical analysis, a new concept utilizing synergistic wrist motion was tested for application in the hand splinting technique utilized following flexor tendon A comparison of the tendon excursions in three different postoperative treatment repair. regimens was performed on cadaveric forearms under simulated passive and isotonic muscle tensions. Using the conventional dorsal splint with rubber band, the excursions of the flexor profundus (FP) and flexor superficialis (FS) in zone II were 10.1 and 7.8 mm, respectively. The relative motion between these two tendons was 2.3 nun. Using the same the tendon excursions increased to splint modified with an additional bar across the palm, However, 15 mm and 13 mm for FP and FS, respectively. using the technique employing synergistic wrist motion, the corresponding tendon excursions were 19.8 and 15.2 mm and relative tendon glide was 4.6 mm. Although the synergistic wrist motion technique increased flexor tendon excursion in zones II and III, excursion was less in zone V than with the other two orthoses, suggesting that synergistic wrist motion improves tendon excursion without increasing tension in the flexor muscles.

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