ABSTRACT
BACKGROUND: This study aimed to compare the effects of plyometric and ankle stability exercises on the dynamic balance and lower limb kinematic and kinetic parameters of Taekwondo demonstration athletes with functional ankle instability. METHODS: Fourteen subjects participated in this study and were randomly divided into two groups: a plyometric exercise group (n = 7) and an ankle stability exercise group (n = 7). Exercises were performed twice a week for 8 weeks. A Y-balance test was used to measure dynamic balance, and a motion analysis system and force plate were used to collect kinematic and kinetic parameters during single-leg drop landing. A paired t-test was used for intragroup comparisons, and an independent t-test was used for intergroup comparisons. RESULTS: In both groups, exercise increased dynamic balance and shock absorption and reduced postural sway on the anteroposterior displacement (p < 0.05). The plyometric exercise group decreased their ankle dorsiflexion and increased their knee and hip joint flexion at maximum knee flexion (p < 0.05). In contrast, the stability exercise increased their ankle plantar flexion at initial contact (p < 0.05). CONCLUSIONS: The plyometric exercise group altered their landing strategies using their knee and hip joints to control ankle instability at landing. This study suggests that the application of plyometric exercises in ankle rehabilitation would improve stability and shock absorption and help prevent injuries during Taekwondo demonstrations.
Subject(s)
Joint Instability , Leg , Plyometric Exercise , Ankle , Athletes , Humans , Leg/physiology , Young AdultABSTRACT
Selaginella martensii, an evergreen perennial fern that is native to South America and New Zealand, is named "frosty fern" because of its beautiful white-colored leaves and it is used as an ornamental plant. Efficient propagation methods for this species have not been developed. We aimed to develop an efficient propagation method for S. martensii through in vitro culture. We investigated culture conditions that are suitable for shoot-tip proliferation and growth. The optimum shoot-tip culture conditions were determined while using Murashige and Skoog (MS) medium (quarter, half, full, or double strength) and macronutrients (sucrose and two nitrogen sources) at various concentrations. In MS medium, the shoot tips formed a maximum of 6.77 nodes per explant, and each node formed two new shoot tips (i.e., 26 or 64 shoot tips). When using branching segments containing an angle meristem, the shoot-to-rhizophore formation ratio could be controlled by medium supplementation with plant-growth regulators. Sporophytes that were grown from shoot tips in vitro were acclimated in ex vitro soil conditions and successfully survived in the greenhouse. Numerous shoot tips could be obtained from in vitro-grown sporophytes and be proliferated ex vitro to produce a large number of plants. This method provides a way of shortening the time that is required for producing a large stock of S. martensii planting material.
