Effects of stretching on passive muscle tension and response to eccentric exercise.
BACKGROUND
Stretching is used in an attempt to improve performance and reduce the risk of muscle injury, with little evidence to support its effectiveness.


OBJECTIVE
Four weeks of static or ballistic stretching can attenuate the increased soreness and decreased flexibility seen after eccentric exercise.


METHODS
Controlled laboratory study.


METHODS
Twenty-nine male subjects were randomly assigned to a static stretching, ballistic stretching, or control group. On each of 4 consecutive days, they completed 4 maximal range of motion stretches using a Cybex isokinetic dynamometer to passively stretch the hamstrings at 0.087 rad.s(-1) (5 deg.s(-1)). Stiffness from 0.87 to 1.48 rad (50 degrees -85 degrees ), peak range of motion, work absorption, peak resistive torque, and soreness were measured. Participants then completed 4 weeks of either static or ballistic stretching for a total stretching duration of 3600 seconds. After training, the 4 days of testing were repeated with an eccentric exercise task added after day 1.


RESULTS
Stretching groups had an increase in range of motion and stretch tolerance after 4 weeks of stretching, with no change in muscle stiffness, work absorption, or delayed onset muscle soreness. After eccentric exercise, they also had greater range of motion and stretch tolerance than did controls.


CONCLUSIONS
Both static stretching and ballistic stretching increase range of motion, most likely as a result of enhanced stretch tolerance rather than changes in muscle elasticity. Four weeks of stretching maintain range of motion and stretch tolerance in the days after eccentric exercise.
LaRoche
Dain P
DP
Department of Environmental and Health Sciences, Johnson State College, 337 College Hill, Johnson, VT 05656, USA. laroched@jsc.vsc.edu
Connolly
Declan A J
DA
D000293:Adolescent; D000328:Adult; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D013848:Thigh / Q000502:physiology