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Vibration and Stretching Effects on Flexibility and Explosive Strength in Young Gymnasts

KINSER, ANN M.1; RAMSEY, MICHAEL W.1; O'BRYANT, HAROLD S.2; AYRES, CHRISTOPHER A.1; SANDS, WILLIAM A.3; STONE, MICHAEL H.1

Medicine & Science in Sports & Exercise: January 2008 - Volume 40 - Issue 1 - pp 133-140
doi: 10.1249/mss.0b013e3181586b13
APPLIED SCIENCES: Biodynamics

Purpose: Effects of simultaneous vibration-stretching on flexibility and explosive strength in competitive female gymnasts were examined.

Methods: Twenty-two female athletes (age = 11.3 ± 2.6 yr; body mass = 35.3 ± 11.6 kg; competitive levels = 3-9) composed the simultaneous vibration-stretching (VS) group, which performed both tests. Flexibility testing control groups were stretching-only (SF) (N = 7) and vibration-only (VF) (N = 8). Explosive strength-control groups were stretching-only (SES) (N = 8) and vibration-only (VES) (N = 7). Vibration (30 Hz, 2-mm displacement) was applied to four sites, four times for 10 s, with 5 s of rest in between. Right and left forward-split (RFS and LFS) flexibility was measured by the distance between the ground and the anterior suprailiac spine. A force plate (sampling rate, 1000 Hz) recorded countermovement and static jump characteristics. Explosive strength variables included flight time, jump height, peak force, instantaneous forces, and rates of force development. Data were analyzed using Bonferroni adjusted paired t-tests.

Results: VS had statistically increased flexibility (P) and large effect sizes (d) in both the RFS (P = 1.28 × 10−7, d = 0.67) and LFS (P = 2.35 × 10−7, d = 0.72). VS had statistically different results of favored (FL) (P = 4.67 × 10−8, d= 0.78) and nonfavored (NFL) (P = 7.97 × 10−10, d = 0.65) legs. VF resulted in statistical increases in flexibility and medium d on RFS (P = 6.98 × 10−3, d = 0.25) and statistically increased flexibility on VF NFL flexibility (P = 0.002, d = 0.31). SF had no statistical difference between measures and small d. For explosive strength, there were no statistical differences in variables in the VS, SES, and VES for the pre- versus posttreatment tests.

Conclusions: Simultaneous vibration and stretching may greatly increase flexibility while not altering explosive strength.

1Sports Performance Enhancement Consortium, Kinesiology, Leisure, and Sports Science, East Tennessee State University, Johnson City, TN; 2Biomechanics Laboratory, Appalachian State University, Boone, NC; and 3Head, Biomechanics and Engineering, United States Olympic Committee, Colorado Springs, CO

Address for correspondence: Michael H. Stone, East Tennessee State University, PO Box 70654; E-mail: stonem@etsu.edu.

Submitted for publication May 2007.

Accepted for publication August 2007.

© 2008 American College of Sports Medicine