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The effect of different stretching techniques on ankle joint range of motion and dynamic postural stability after landing.

BACKGROUND
Stretching improves the flexibility of skeletal muscles, increases the range of motion (ROM) of joints. Stretching is important in prevention of sport-related injuries and influences muscle strength and performance. The effects of Static Stretching (SS) and Cyclic Stretching (CS) have been assessed by examining ROM, muscle power, vertical jump performance. However, the effects on postural control after CS compared with SS does not provide evidence for postural control after landing. The aim of this study was to examine the effects of stretching on the range of motion (ROM) of the ankle joint and dynamic postural stability upon landing on one leg.


METHODS
Twenty healthy subjects participated in this study. Participants were randomly assigned to SS, CS, and control conditions. The ankle was stretched in each condition for two minutes in a standing position. In the assessment of dynamic postural stability, the participant jumped and landed on one leg onto a force platform and the Dynamic Postural Stability Index (DPSI) was measured. Stability indices including those for medial-lateral, anterior-posterior, and vertical stability were calculated. The data were compared among 3 conditions with repeated measures ANOVA and the correlation between ankle range of motion (ROM), DPSI and the maximum vertical ground reaction force (vGRF max) were calculated.


RESULTS
The results indicated that the ROM was significantly greater after SS and CS compared with the control condition. A signiﬁcant improvement in DPSI was observed after CS.


CONCLUSIONS
We showed that 2 minutes of CS had a positive influence on dynamic postural stability after landing on a single leg. Furthermore, CS may improve balance by increasing postural stability.