Once again , new study supports what I have always advocated an active warmup like drills or running ~5
minutes at 60% effort prior to a workout or run. If you stretch, try
after your run.
Journal of Athletic Training 2012:47(1):5-14
© by the National Athletic Trainers' Association, Inc
www.nata.orgljat
original researCh.
Acute Lower Extremity Running Kinematics
After a Hamstring Stretch
Autumn L. Davis Hammonds, MS, ATC*; Kevin G. Laudner, PhD, ATCt;
Steve McCaw, PhDt; Todd A. McLoda, PhD, ATCt
*Austin Peay State University, Clarksville, TN; tillinois State University, Normal
Context: 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.
Design: Randomized controlled clinical trial.
Setting: Biomechanics research laboratory.
Patients or Other Participants: Thirty-four male (age =
21.2 ± 1.4 years) and female (age = 21.3 ± 2.0 years) recreational
athletes.
Intervention(s): 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.
Main Outcome Measure(s): Six 2-way analyses of variance
to determine joint angle differences between groups at maximum
hip flexion and maximum knee extension with an a level
of .008.
Results: Flexibility increased between pretest and posttest
in all participants (F1,30 = 80.61, P< .001). Anterior pelvic tilt
(F1,30=0.73, P=.40), hip flexion (F1,30=2.44, P=.13), and knee
extension (F1,30=0.06, P=.80) at maximum hip flexion were
similar between groups throughout testing. Anterior pelvic tilt
(F1,30=0.69, P=.41), hip flexion (F1,30=0.23, P=.64), and knee
extension (F1,30 =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
(F1,30=13.62, P=.001).
Conclusions: A single session of 3 straight-leg raise hamstring
stretches did not change pelvis, hip, or knee running kinematics.
Key Words: straight-leg raises, flexibility