title: Gains in flexibility related to measures of muscular performance: impact of flexibility on muscular performance.
abstract: OBJECTIVE
  Studies that investigated possible correlations between flexibility and muscular performance are scarce in the literature. Therefore, the purpose of this study was to investigate the impact of a program of static stretching on the flexibility of the hamstrings and on muscular performance of the knee flexors and extensors.
  
  
  METHODS
  Pre-post experimental design.
  
  
  METHODS
  University laboratory.
  
  
  METHODS
  Thirty subjects aged 22.8 +/- 4.9 years with bilaterally shortened hamstrings.
  
  
  METHODS
  Using a protocol that has been previously described, the intervention consisted of 30 sessions of static stretching, performed bilaterally five times a week for 6 weeks.
  
  
  METHODS
  Measures of knee range of motion and isokinetic muscular performance (peak torque, angle of peak torque, and work) of knee flexors and extensors at speeds of 60 and 300 degrees/s.
  
  
  RESULTS
  After intervention, significant gains in measures of flexibility (P < 0.0001) were observed, with an average gain of the knee-extension angle of 12.6 degrees, ranging from -1.2 to 30.7 degrees. In addition, we found significant increases in the following parameters of muscular performance: angle of peak torque of hamstrings at 60 and 300 degrees/s (P < 0.0001 and 0.018) and for work at 60 and 300 degrees/s for knee flexors (P = 0.012 and 0.005) and for knee extensors (P < 0.0001).
  
  
  CONCLUSIONS
  The intervention resulted in gains in measures of flexibility, and these gains had a positive impact on some parameters of muscular performance.
authors.affiliation: Department of Physical Therapy, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
authors.forename: Gustavo Nunes Tasca
authors.initials: GN
authors.lastname: Ferreira
authors.forename: Luci Fuscaldi
authors.initials: LF
authors.lastname: Teixeira-Salmela
authors.forename: Cristiano Queiroz
authors.initials: CQ
authors.lastname: Guimarães
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil; D005260:Female; D006801:Humans; D007719:Knee Joint; D007866:Leg / Q000502:physiology*; D008297:Male; D052580:Muscle Stretching Exercises; D018482:Muscle, Skeletal / Q000502:physiology*; D018583:Pliability; D019415:Torque