Comparison of ballistic and static stretching on hamstring muscle length using an equal stretching dose.

The purpose of this investigation was to determine which stretching technique, static or ballistic, is most effective for increasing hamstring muscle length when delivered at the same stretching dose over a 4-week training program. A single-blind, randomized controlled trial design was used in this investigation. Thirty-two participants (16 women and 16 men) between the ages of 18 and 27 years participated in the study. All participants who had a pre-training knee extension angle of less than 20° were excluded from the study. Subjects were randomly assigned to one of 3 groups: ballistic stretching, static stretching, or control group. Participants in the experimental stretching groups (ballistic and static stretching) performed one 30-second stretch 3 times per week for a period of 4 weeks. Statistical analysis consisted of a 2-way analysis of variance (group × sex) with an a priori alpha level of 0.05. No interaction between group and sex was identified (p = 0.4217). The main effect of sex was not statistically significant (p = 0.2099). The main effect for group was statistically significant at p < 0.0001. Post hoc analysis revealed that both static and ballistic stretching group produced greater increases in hamstring length than the control group. The static stretching group demonstrated a statistically greater increase in hamstring muscle length than the ballistic stretching group. No injuries or complications were attributed to either stretching program.

Variables associated with level of disability in working individuals with nonacute low back pain: a cross-sectional investigation.

STUDY DESIGN: Single-site, exploratory, cross-sectional design. OBJECTIVE: To identify variables associated with disability related to low back pain (LBP), as measured by the modified Oswestry Low Back Pain Disability Questionnaire (mOSW), in a sample of working adults with nonacute LBP. BACKGROUND: Compared to acute LBP, there is little information available in the literature to identify variables associated with LBP-related disability in working individuals with stage 2 and stage 3 LBP. METHODS: Data analyzed were from working individuals with nonacute LBP (n = 235). The response variable was dichotomized by mOSW score (less than 20 or 20 or greater), and the regressor variables included 27 self-report, sociodemographic, impairment-based, and kinematic measures used to assess individuals with LBP. Logistic regression was used to identify variables associated with mOSW. RESULTS: One hundred eleven subjects had a mOSW score of 20 or greater, and 124 subjects had a mOSW score of less than 20. Logistic regression analysis identified 4 variables associated with LBP-related disability (mOSW): duration of LBP (P = .006), numeric pain rating (P<.0001), Fear-Avoidance Beliefs Questionnaire physical activity subscale (P = .0007), and limits of stability movement velocity in the forward direction (P = .02). The best model had an R2(u) of 0.25. CONCLUSION: The odds of LBP-related disability (mOSW) in this sample of nonacute working individuals were found to increase with longer duration of LBP, higher numeric pain rating scores, higher Fear-Avoidance Beliefs Questionnaire physical activity subscale scores, and slower limits of stability movement velocity in the forward direction. The identification of limits of stability movement velocity is a novel finding that may support a link between sensorimotor balance deficits and disability in working individuals with nonacute LBP.

The relationship of body segment length and vertical jump displacement in recreational athletes.

The purpose of this study was to determine if segmental skeletal length contributes to vertical jump (VJ) displacement in recreational athletes. Skeletal length measurements of the trunk, femur, tibia, and foot were obtained by palpation of bony landmarks and a standard tape measure. A pilot study (n = 10) examined the intratester and intertester reliability for each skeletal measure. The pilot investigation revealed fair to excellent intratester and intertester reliability. Seventy-eight recreational athletes (55 men and 23 women) with a mean age of 21.9 +/- 2.9 years participated in the investigation. Multiple regression analysis with gender as a categorical indicator variable revealed a significant gender difference; therefore, men and women were analyzed separately. Regression analysis for men identified foot length (p < 0.033, R(2) = 0.08) as the only significant skeletal length predictor of VJ displacement. None of the skeletal length measures was predictive of VJ displacement in women. Based on the results of this investigation, intrinsic skeletal length is not a strong predictor of VJ displacement in young adult recreational athletes.