title: Roller-massager application to the hamstrings increases sit-and-reach range of motion within five to ten seconds without performance impairments.
abstract: BACKGROUND
  Foam rollers are used to mimic myofascial release techniques and have been used by therapists, athletes, and the general public alike to increase range of motion (ROM) and alleviate pressure points. The roller-massager was designed to serve a similar purpose but is a more portable device that uses the upper body rather than body mass to provide the rolling force.
  
  
  OBJECTIVE
  A roller massager was used in this study to examine the acute effects on lower extremity ROM and subsequent muscle length performance.
  
  
  METHODS
  Seven male and ten female volunteers took part in 4 trials of hamstrings roller-massager rolling (1 set - 5 seconds, 1 set - 10 seconds, 2 sets - 5 seconds, and 2 sets - 10 seconds) at a constant pressure (13 kgs) and a constant rate (120 bpm). A group of 9 participants (three male, six female) also performed a control testing session with no rolling intervention. A sit and reach test for ROM, along with a maximal voluntary contraction (MVC) force and muscle activation of the hamstrings were measured before and after each session of rolling.
  
  
  RESULTS
  A main effect for testing time (p<0.0001) illustrated that the use of the roller-massager resulted in a 4.3% increase in ROM. There was a trend (p=0.069) for 10s of rolling duration to increase ROM more than 5s rolling duration. There were no significant changes in MVC force or MVC EMG activity after the rolling intervention.
  
  
  CONCLUSIONS
  The use of the roller-massager had no significant effect on muscle strength, and can provide statistically significant increases in ROM, particularly when used for a longer duration.
authors.affiliation: Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Sullivan
authors.forename: Dustin B J
authors.initials: DB
authors.lastname: Silvey
authors.forename: Duane C
authors.initials: DC
authors.lastname: Button
authors.forename: David G
authors.initials: DG
authors.lastname: Behm
keywords: Flexibility; hamstrings; performance; roller‐massager; self myofascial release; stretching