How does static stretching influence the tendons mechanical response?
OBJECTIVE
Analyze in vitro the mechanical response of bovine calcaneus tendons subjected to static stretching in three different intervals (15, 30, 45 s).


METHODS
Six groups of bovine calcaneus tendons (n=10) were formed according to the static stretching protocol: three different intervals (15, 30, 45 s) and initial stretching percentage (2.5% and 3.5%). The control group (n=10) did not perform prior stretching. At the end of the stretching tests, the specimens were subjected to stress rupture tests.


RESULTS
The values for force relaxation presented stability after the 30(th) second (p<0.0001) at both levels of deformation. Greater force relaxation (p<0.0026) and the least tensile strength (p=0.0123) was observed in the group that was subjected to the highest stretch percentage (3.5%). No difference was observed between the rupture parameters of the stretch and control groups. The variables, stretch duration and percentage did not demonstrate interaction.


CONCLUSIONS
In relation to force relaxation, the 30 second interval seems to be the most effective when stretching tendons. This fact should be considered when establishing new clinical stretching protocols. Laboratory investigation.
Sport and e Exercise and Sports Medicine of School of Medical Scineces of State University of Campinas - Unicamp. Campinas, SP, Brazil.
Nathalia Polisello
NP
Rossetto
Sport and e Exercise and Sports Medicine of School of Medical Scineces of State University of Campinas - Unicamp. Campinas, SP, Brazil.
Inácio Maria Dal
IM
Fabbro
Sport and e Exercise and Sports Medicine of School of Medical Scineces of State University of Campinas - Unicamp. Campinas, SP, Brazil.
Sérgio Rocha
SR
Piedade
Biomechanics; Collagen; Tendons; Time