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Objective: To study the protective effect of parachute ankle brace on ankle joint during simulated parachuting landing. Methods: In August 2021, 30 male paratroopers were selected as the test subjects by simple random sampling method. They jumped from the 1.5 m and 2.0 m height platforms respectively with and without parachute ankle brace, and landed on the sandy ground in a semi-squat parachute landing position. The experiment was divided into 1.5 m experimental group and control group and 2.0 m experimental group and control group. Angle sensor and surface electromyograph were used to measure and analyze the coronal tilt range of the ankle joint and the percentage of maximal voluntary contraction (MVE%) of the muscles around the ankle joint, respectively, to evaluate the protective effect of the parachute ankle brace. Results: At the same height, the tilt range of coronal plane of ankle in experimental group was significantly reduced compared with control group, and the difference was statistically significant (P<0.05). Under the same protection state, the tilt range of the coronal plane of the ankle in the 1.5 m group was significantly reduced compared with that in the 2.0 m group, and the difference was statistically significant (P<0.05). The coronal plane inclination range of the ankle in 2 m experimental group was significantly lower than that in 1.5 m control group, and the difference was statistically significant (P<0.05). Compared with 1.5 m control group, MVE% of right tibialis anterior muscle and bilateral lateral gastrocnemius decreased in 1.5 m experimental group, while MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle and right lateral gastrocnemius decreased in 2.0 m experimental group, while the MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). The MVE% of bilateral tibialis anterior muscle, bilateral lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m experimental group decreased compared with 2.0 m experimental group, and the differences were statistically significant (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle, right lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m control group decreased, and the differences were statistically significant (P<0.05) . Conclusion: Wearing parachute ankle brace can effectively limit the coronal plane inclination range of ankle joint, improve the stability of ankle joint and reduce the load on the muscles around ankle joint by landing. Reducing the height of the jumping platform can reduce the coronal plane incline range of the ankle and the muscle load around the ankle during landing.
Subject(s)
Humans , Male , Ankle , Ankle Joint/physiology , Lower Extremity/physiology , Muscle, Skeletal/physiology , ElectromyographyABSTRACT
Objective To examine the effects of ankle brace on biomechanics of the lower extremity during landing, so as to provide a theoretic support to choose ankle brace for people with different sports levels. Methods The key words (ankle brace OR ankle braces OR ankle bracing OR ankle support) AND (landing OR land OR jump OR hopped OR hopping) AND (biomechanics OR kinematics OR kinetics OR electromyography OR neuromuscular) in Chinese and English were searched from different electronic databases (CNKI, Web of Science, EBSCO, PubMed and other databases), for a period of Jan. 2000 to Dec. 2020. Cochrane was used to evaluate the quality of eligible studies. For meta analysis, subgroup analysis was used to assess the impact of ankle braces on ankle biomechanics.Results Thirteen studies with a total of 222 participants were included for mata analysis in this study. The semi-rigid ankle brace reduced the peak of ankle inversion by 25.8% compared with the elastic ankle brace (SMD=-0.562, P<0.001). Moreover, the elastic ankle brace reduced ankle plant flexion during landing among athletes (SMD=-3.42, P=-0.021). As for collagiate students, both elastic ankle and semi-rigid ankle decreased the ankle inversion (elastic ankle brace: 35.4%, SMD=-1.000, P=-0.013; semi-rigid ankle brace: 31.11%, SMD=-0.881, P<0.001) and ankle plant flexion (elastic ankle brace:23.30%, SMD=-1.381, P<0.001;semi-rigid ankle brace: 36.33%, SMD=-1.605, P<0.001).Conclusions Both ankle braces can prevent ankle sprain for athletes (basketball, volleyball, running) who experience training more than 5 years. The elastic ankle brace can limit the inversion and plantar flexion, while the semi-rigid ankle brace can merely decrease the ankle inversion. Therefore, athletes are more suitable for the elastic ankle brace. As for collegiate students without training history, both ankle brace can decrease the ankle inversion and plantar flexion. The elastic ankle brace has greater restriction on inversion, while the semi-rigid ankle brace has more restriction on plantar flexion. Therefore, the elastic ankle brace should be utilized if collegiate students have calcaneofibular ligament injury, while the semi-rigid ankle brace is more suitable for collegiate students who have a history of anterior talofibular ligament injury.
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Objective To explore the mechanism of ankle sprain varus, a kind of human ankle brace with asymmetric physiological structure which can protect the ankle effectively is designed. Methods The anatomic factors of ankle varus were analyzed firstly, and a kind of ankle brace with asymmetric structure was designed based on asymmetric structure of ankle joint by anatomy. Using Kinect system and Geomagic Studio software, 3D scanning and digital modeling on ankle joint of a male adult were performed, and the ankle model was established by 3D printing technology. With EVA film, silica gel film and wrapped edge copper network as raw materials, two kinds of ankle brace with asymmetric structure were prepared by 3D draping and composite materials processing technology. The shaping properties, tensile properties, fatigue performance, outer fabric breathability and friction of the designed brace were tested. Results The outside of ankle brace with asymmetric structure had good shaping property, low tensile elastic recovery rate. Under the effect of repeated small load, EVA composite materials and silicone composite materials could keep good elastic recovery and effectively bear external varus forces. The results from air permeability and grinding test showed that polyester material was a kind of suitable fabrics for the outer lining material. Conclusions The mechanical properties of ankle brace with asymmetric structure can meet the requirement of ankle varus protection. The fabric of ankle brace can improve moisture permeability and frictional properties.
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Ankle sprains are one of the most common surgical injuries in clinic. In this article, the foot anatomy structure was elaborated, and the biomechanics of ankle ligaments during sports was mainly reviewed. At the same time, the mechanism of ankle sprains was analyzed, the principal means of ankle sprains, prevention and rehabilitation at present were summarized, and the use of ankle braces to prevent ankle sprains as well as its research progress were introduced emphatically. The classification and characteristics of ankle braces were then summarized, and the prevention of ankle sprains and development of ankle braces were prospected. The multiple ankle lateral ligament damage was due to the physiological structure differences between lateral and medial ligaments of the ankle joints, and such structure characteristic should be considered while improving ankle braces and designing new ankle braces. Wearing ankle braces plays a key role in ankle sprains protection, which can shorten the recovery time and avoid re-injury in clinical rehabilitation. For rehabilitation of severe ankle sprains, semi-rigid ankle braces are better than elastic ones.
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Objective To study effects of ankle stabilizer on electromyographic activities of lower extremity muscles during the simulated half squat parachute landing and its gender differences. Method Eight male and eight female healthy adults were required to jump from a platform of 0.72 m high to simulate half squat parachute landing. The experiment was divided into 3 groups: the barefoot one as control group, the group wearing tapes and braces respectively. The electromyogram (EMG) of each subject’s tibial anterior, lateral gastrocnemius, biceps femoralis and rectus femoralis was measured. Two way ANOVA was used to analyze and evaluate the effect of the stabilizers and genders on EMG variables. Results The use of brace significantly increased the pre landing EMG amplitude of the tibialis anterior for male (Control: 266 μV; Tape: 368 μV; Brace: 552 μV). The stabilizers had no significant effects on the other EMG parameters. Conclusions Semi rigid ankle braces are capable of arousing more active EMG of male’s ankle flexor during half squat parachute landing, but female does not share this predominance. Ankle stabilizers have no significant effects on EMG activities for knee joints.
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OBJECTIVE: To determine the effects of subtalar joint ankle brace used with shoes on static postural sway and limb load asymmetry (LLA) in elderly. METHOD: 620 healthy adults volunteered. These subjects were administered with the balance test on three different conditions, with bare foot, with shoes only and with aircast and shoes. All subjects were divided into two groups; younger ( or =65 years) group and tested for LLA and postural sway with a balance tester. RESULTS: In both younger and older group, wearing shoes only and wearing ankle brace with shoes reduced the LLA and postural sway significantly compared to bare foot condition (p<0.05). In older group, there was also significant LLA and postural sway reduction in wearing ankle brace with shoes compared to wearing shoes only (p<0.05). The differences of LLA between bare foot and ankle brace with shoes in older group was more prominent than in younger group (p<0.05). CONCLUSION: Wearing a subtalar joint ankle brace with shoes improved right-left static postural balance as compared with wearing shoes alone in elderly.
Subject(s)
Adult , Aged , Animals , Humans , Ankle , Braces , Extremities , Foot , Postural Balance , Shoes , Subtalar JointABSTRACT
OBJECTIVE: This study was designed to evaluate the effect of ankle bracing (Aircast) on postural sway and limb load asymmetry (LLA) in normal adults. METHOD: 263 healthy subjects volunteered. These subjects were performed the balance test on three different conditions, 1st test fulfilled without ankle brace, 2nd test with aircast on one ankle and 3rd test with aircast on the other ankle. All subjects were divided into two groups; younger( or = 65 years) group. Postural sway and body weight distribution were recorded while the subjects were standing on two adjacent force platforms during 30 seconds trial. All subjects chose a comfortable stance with feet apart and asked to look straight ahead at a fixed point in a quiet room. RESULTS: There were significant differences not only in LLA but also in postural sway between younger and older group. The difference of postural sway and LLA in older group was more prominent that in younger group (p<0.05). CONCLUSION: The results indicated that ankle bracing improved postural sway irrespective of age. Moreover in older group, ankle bracing on one ankle that was in the absence of LLA improved postural sway by far.