title: Acute enhancement of lower-extremity dynamic strength and flexibility with whole-body vibration.
abstract: The purpose of this investigation was to examine the acute effects of whole-body vibration (WBV) on muscular strength, flexibility, and heart rate (HR). Twenty adults (10 men, 10 women) untrained to WBV participated in the study. All subjects completed assessment of lower-extremity isokinetic torque, flexibility, and HR immediately before and after 6 minutes of WBV and 6 minutes of leg cycling ergometry (CYL), in randomized order. During WBV, subjects stood upright on a vibration platform for a total of 6 minutes. Vibration frequency was gradually increased during the first minute to a frequency of 26 Hz, which was maintained for the remaining 5 minutes. During CYL, power output was gradually increased to 50 W during the first minute and maintained at that power output for the remaining 5 minutes. Lower-extremity flexibility was determined using the sit-and-reach box test. Peak and average isokinetic torque of knee extension and flexion were measured by means of a motor-driven dynamometer with velocity fixed at 120 degrees .s. Change scores for the outcome measures were compared between treatments using Student's paired t-tests. Analysis revealed significantly greater HR acceleration with CYL (24.7 bpm) than after WBV (15.8 bpm). The increase of sit-and-reach scores after WBV (4.7 cm) was statistically greater (p < 0.05) than after CYL (0.8 cm). After WBV, increases in peak and average isokinetic torque of knee extension, 7.7% and 9.6%, were statistically greater than after CYL (p < 0.05). Average torque of knee flexion also increased more with WBV (+7.8%) than with CYL (-1.5%) (p < 0.05). The findings of this study indicate that short-term WBV standing elicits acute enhancements of lower-extremity muscular torque and flexibility, suggesting the application of this technology as a preparatory activity before more intense exercise.
authors.affiliation: Exercise Science and Health Promotion Department, Florida Atlantic University, Davie, Florida, USA. pjacobs4@fau.edu
authors.forename: Patrick L
authors.initials: PL
authors.lastname: Jacobs
authors.forename: Patricia
authors.initials: P
authors.lastname: Burns
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D016552:Ergometry; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D035002:Lower Extremity; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology; D012680:Sensitivity and Specificity; D013997:Time Factors; D019415:Torque; D014732:Vibration; D055815:Young Adult