title: Mechanical evaluation of elastic tubes used in physical therapy.
abstract: OBJECTIVE
  To quantify the force of elastic tubes at different elongation patterns used in exercises.
  
  
  METHODS
  A tensile test of elastic tubes which had seven levels of resistance identified by colors was performed. All samples (n = 105; 15 samples for each color) were 7 cm of length and had two interfaces for fixation. The samples were tested in a tensile testing hydraulic machine, under elongation control, up to 200% of the original length (21 cm). The force values corresponding to an increase of 50%, 100%, 150% and 200% of the samples initial length were recorded.
  
  
  RESULTS
  A strong linear association between force and elongation for all colors was found. There were different forces for each elongation investigated for the same tube and between different tubes in almost all percentage of elongation investigated, except for the red and green tubes (all elongations), and for the blue and black tubes at 50% elongation.
  
  
  CONCLUSIONS
  Mechanical tests revealed different elastic forces for different levels of elongation of each tube. The replication of the results in clinical situations is recommended, so the elastic resistance in clinical routine could be evaluated with more propriety.
authors.affiliation: Faculty of Physical Therapy .
authors.forename: Wagner Rodrigues
authors.initials: WR
authors.lastname: Martins
authors.forename: Rodrigo Storck
authors.initials: RS
authors.lastname: Carvalho
authors.forename: Michel Santos
authors.initials: MS
authors.lastname: Silva
authors.forename: Juscelino Castro
authors.initials: JC
authors.lastname: Blasczyk
authors.forename: José Alexander
authors.initials: JA
authors.lastname: Araújo
authors.forename: Jake
authors.initials: J
authors.lastname: do Carmo
authors.forename: André Luiz Felix
authors.initials: AL
authors.lastname: Rodacki
authors.forename: Ricardo Jacó
authors.initials: RJ
authors.lastname: de Oliveira
mesh_terms: D004548:Elasticity; D004867:Equipment Design; D016014:Linear Models; D008422:Materials Testing; D055070:Resistance Training / Q000295:instrumentation*; D013718:Tensile Strength