P. Malaviya et al., In vivo tendon forces correlate with activity level and remain bounded: evidence in a rabbit flexor tendon model, J BIOMECHAN, 31(11), 1998, pp. 1043-1049
While some tendons and ligaments in the lower extremity develop peak forces
proportional to the intensity of activity (Komi 1990; Komi et al., 1992; K
orvick et al., 1996), others maintain a steady force regardless of activity
level (Herzog et al., 1993; Prilutsky et al., 1994). Investigators (Biewen
er et al., 1988; Korvick et al., 1996) have also shown that peak knee and a
nkle tendon forces approach one-quarter to one-third of ultimate or failure
force values. In the rabbit flexor digitorum profundus (FDP) tendon model
we tested several hypotheses, chiefly that peak in vivo forces not only inc
rease with increasing activity but do not exceed one-third of their ultimat
e or failure values. The FDP tendon was instrumented in three animals, and
each rabbit subjected to an experimental design involving three activity le
vels. Peak tensile forces and rates of rise and fall in tendon force increa
sed significantly with increasing activity(p < 0.01). Further, the tendon m
aintained a non-zero force level throughout all trials. For the most vigoro
us activity, inclined hopping, tensile forces and stresses were, on average
, within 30% of the tendon's ultimate force and stress values, respectively
. Such in vivo measurements in different tendon systems should help investi
gators better understand the recruitment and contribution of important musc
le-tendon units to joint stability and gait. (C) 1998 Elsevier Science Ltd.
All rights reserved.