A Comparison of Static Stretching Versus Combined Static and Ballistic Stretching in Active Knee Range of Motion

Abstract

Background: There is continued controversy related to flexibility gains from different stretching protocols and within single protocols. Stretching methods include static, ballistic, dynamic, and proprioceptive neuromuscular facilitation (PNF). A combination of stretching methods may be an improved way to increase active knee range of motion (ROM). This study evaluated a single program formulated with static and ballistic components. Objective: To compare active knee ROM following stretching programs which either included combined static and ballistic stretching (CSBS) or static stretching (SS) alone. It was hypothesized that CSBS would show a greater increase in active knee ROM than SS. Setting: The pre- and post- measurements were performed in a laboratory. Subjects were randomly assigned to either treatment group or a non-stretching control group and given written instructions on how to perform their designated protocol at home. Subjects: Forty-three (33M, 10F) healthy collegiate aged participants (24.0 + 3.69 yrs, 176.21 + 10.0 cm, 78.15 + 12.93 kg) with no history of injury to the lower extremity or low back for the previous 6 months were eligible to participate in the study. Interventions: Two treatment groups either performed SS or CSBS for 30 seconds on each leg, twice a day for 2 weeks. All subjects but 3 provided both legs, and each leg was evaluated separately, providing 83 total measurements. Main Outcome Measures: A Johnson Digital Inclinometer was used to measure active knee extension. A mixed ANOVA with a Tukey post hoc test was used for statistical analysis. Results: There was no statistically significant difference in active knee ROM between groups at the pre-test, F(2,80)=1.062, p=.351, partial ƞ2=.026 (SS: 52.56 + 7.50º, CSBS: 49.84 + 8.91⁰, control: 49.39 + 10.09⁰). There was a statistically significant difference in active knee ROM between groups at the post-test, F(2,80)=29.034, p .05). There was homogeneity of covariance’s, as assessed by Box's test of equality of covariance matrices (p = .076). There was homogeneity of variances, as assessed by Levene's test of homogeneity of variance (p>.05). Conclusions: SS and CSBS are equally effective for improving active knee ROM. A trend indicating CSBS showing only slightly greater differences may be due to limited time allowed to master the CSBS method, with no supervision during stretching sessions.