title: Acute lower extremity running kinematics after a hamstring stretch.
abstract: BACKGROUND
  Limited passive hamstring flexibility might affect kinematics, performance, and injury risk during running. Preactivity static straight-leg raise stretching often is used to gain passive hamstring flexibility.
  
  
  OBJECTIVE
  To investigate the acute effects of a single session of passive hamstring stretching on pelvic, hip, and knee kinematics during the swing phase of running.
  
  
  METHODS
  Randomized controlled clinical trial.
  
  
  METHODS
  Biomechanics research laboratory.
  
  
  METHODS
  Thirty-four male (age = 21.2 ± 1.4 years) and female (age = 21.3 ± 2.0 years) recreational athletes.
  
  
  METHODS
  Participants performed treadmill running pretests and posttests at 70% of their age-predicted maximum heart rate. Pelvis, hip, and knee joint angles during the swing phase of 5 consecutive gait cycles were collected using a motion analysis system. Right and left hamstrings of the intervention group participants were passively stretched 3 times for 30 seconds in random order immediately after the pretest. Control group participants performed no stretching or movement between running sessions.
  
  
  METHODS
  Six 2-way analyses of variance to determine joint angle differences between groups at maximum hip flexion and maximum knee extension with an α level of .008.
  
  
  RESULTS
  Flexibility increased between pretest and posttest in all participants (F(1,30) = 80.61, P < .001). Anterior pelvic tilt (F(1,30) = 0.73, P = .40), hip flexion (F(1,30) = 2.44, P = .13), and knee extension (F(1,30) = 0.06, P = .80) at maximum hip flexion were similar between groups throughout testing. Anterior pelvic tilt (F(1,30) = 0.69, P = .41), hip flexion (F(1,30) = 0.23, P = .64), and knee extension (F(1,30) = 3.38, P = .62) at maximum knee extension were similar between groups throughout testing. Men demonstrated greater anterior pelvic tilt than women at maximum knee extension (F(1,30) = 13.62, P = .001).
  
  
  CONCLUSIONS
  A single session of 3 straight-leg raise hamstring stretches did not change pelvis, hip, or knee running kinematics.
authors.affiliation: Austin Peay State University, Clarksville, TN, USA. davisa@apsu.edu
authors.forename: Autumn L
authors.initials: AL
authors.lastname: Davis Hammonds
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Laudner
authors.forename: Steve
authors.initials: S
authors.lastname: McCaw
authors.forename: Todd A
authors.initials: TA
authors.lastname: McLoda
mesh_terms: D056352:Athletes; D001696:Biomechanical Phenomena; D005260:Female; D006615:Hip / Q000502:physiology; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology; D008297:Male; D052580:Muscle Stretching Exercises; D009129:Muscle Tonus; D018482:Muscle, Skeletal / Q000502:physiology*; D010388:Pelvis / Q000502:physiology; D018583:Pliability; D016059:Range of Motion, Articular / Q000502:physiology*; D012420:Running / Q000502:physiology*; D055815:Young Adult