Article

Ankle Biomechanics during four landing techniques

Department of Engineering Mechanics, USAF Academy, CO 80840-6240, USA.
Medicine & Science in Sports & Exercise (Impact Factor: 3.98). 09/2001; 33(8):1338-44. DOI: 10.1097/00005768-200108000-00015
Source: PubMed

ABSTRACT

An understanding of landing techniques is important for the prevention of injuries in a number of athletic events. There is a risk of injury to the ankle during landings, and the kinematics and forces involved in different landing strategies may be related to the occurrence of trauma.
In the current study, four drop conditions from a 30.48-cm (12-inch) height were tested. The conditions were a) BN: Bent knee (self-selected), Natural (self-selected) plantar flexor contraction; b) SN: Stiff-knee, Natural plantar flexors; c) SP: Stiff-knee, Plantar flexors absorbing the impact; and d) SH: Stiff-knee, absorbing most of the impact in the Heels. Peak vertical forces and accelerations were measured, and Achilles tendon forces and stiffnesses were calculated.
Peak vertical forces and peak tibial accelerations were highest for the SH condition (2418 N and 20.7 G), whereas peak Achilles tendon force was highest for SP drops. The overall average AT stiffness was 166,345 N x m(-1).
The results from the study were used in an extensive cadaver study to investigate ankle injuries. The data from the current study indicate that athletes may not use their full energy absorbing potential in landings during sporting activities.

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    • "Given that landing height has been demonstrated to increase the impact of the foot with the ground [53], we considered that the higher magnitude of F2 observed in our study might be due to higher landing height. However, the landing height in the present study was lower than landing heights documented in previous studies (respectively, 25 cm vs. 30 [30–32, 48], 60 [10, 46], and 62 cm [53]). The persistent plantar-flexed foot in participants with CP may have created a longer moment arm at the foot in relation to the ankle [17], thereby increasing the magnitude of F2. "
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    ABSTRACT: The aim of the present study was to analyse the parameters that characterize the vertical ground reaction force during the landing phase of a jump, and to determine the relationship among these parameters in elite soccer players with cerebral palsy (CP). Thirteen male members of the Spanish national soccer team for people with CP (mean age: 27.1 ± 4.7 years) volunteered for the study. Each participant performed three counter movement jumps. The characteristics of the first peak of the vertical ground reaction force during the landing phase of a jump, which corresponds to the forefoot contact with the ground, were similar to the results obtained in previous studies. However, a higher magnitude of rearfoot contact with the ground (F2) was observed in participants with CP than in participants without CP. Furthermore, a significant correlation between F2 magnitude and the elapsed time until its production (T2) was not observed (r = -0.474 for p = 0.102). This result implies that a landing technique based on a delay in the production of F2 might not be effective to reduce its magnitude, contrary to what has been observed in participants without CP. The absence of a significant correlation between these two parameters in the present study, and the high magnitude of F2, suggest that elite soccer players with CP should use footwear with proper cushioning characteristics.
    Full-text · Article · Jun 2015 · Biology of Sport
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    • "The moment arm was quantified as a function of the ankle sagittal plane angle (AKA) using the procedure described by Self and Paine (2001): ATL = PFM / atma atma = -0.5910 + 0.08297 AKA – 0.0002606 AKA 2 Average and instantaneous ATL loading rates (B·W·s -1 ) were calculated in accordance with the procedure outline by Sinclair et al. (2014). "
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    ABSTRACT: Recreational running is an activity with multiple reported health benefits for both sexes, however, chronic injuries caused by excessive and/or repetitive loading of the Achilles tendon are common. Males have been identified as being at an increased risk of suffering an injury to the Achilles tendon and as such, knowledge of differences in loading between the sexes may provide further information to better understand why this is the case. The aim of the current investigation was to determine whether gender differences in the Achilles tendon load exist in recreational runners. Fifteen male (age 26.74 ± 5.52 years, body height 1.80 ± 0.11 m and body mass 74.22 ± 7.27 kg) and fifteen female (age 25.13 ± 6.39 years, body height 1.68 ± 0.12 m and body mass 67.12 ± 9.11 kg) recreational runners volunteered to take part in the current investigation. Participants completed 10 trials running at 4.0 m·s-1 ±5% striking a force platform (1000 Hz) with their right foot. Ankle joint kinematics were synchronously recorded (250 Hz) using an optoelectric motion capture system. Ankle joint kinetics were computed using Newton-Euler inverse-dynamics. Net external ankle joint moments were then calculated. To estimate Achilles tendon kinetics the plantarflexion moment calculated was divided by an estimated Achilles tendon moment arm of 0.05 m. Differences in Achilles tendon kinetics were examined using independent sample t-tests (p<0.05). The results indicate that males were associated with significantly (p<0.05) greater Achilles tendon loads than females. The findings from this study support the notion that male recreationa lrunners may be at greater risk of Achilles tendon pathology.
    Full-text · Article · Dec 2014 · Journal of Human Kinetics
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    • "Achilles tendon load (ATL) was determined by dividing the plantarflexion moment (MPF) by the estimated Achilles tendon moment arm (MA). The moment arm was quantified as a function of the ankle sagittal plane angle (SAK) using the procedure described by Self and Paine (2001): "
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    ABSTRACT: Background Achilles tendon pathology is a frequently occurring musculoskeletal disorder in runners. Foot orthoses have been shown to reduce the symptoms of pain in runners but their mechanical effects are still not well understood. Methods This study aimed to examine differences in Achilles tendon load when running with and without orthotic intervention. Twelve male runners ran at 4.0 m.s- 1. Ankle joint moments and Achilles tendon forces were compared when running with and without orthotics. Findings The results indicate that running with foot orthotics was associated with significant reductions in Achilles tendon load compared to without orthotics. Interpretation: In addition to providing insight into the mechanical effects of orthotics in runners, the current investigation suggests that via reductions in Achilles tendon load, foot orthoses may serve to reduce the incidence of chronic Achilles tendon pathologies in runners.
    Full-text · Article · Aug 2014 · Clinical biomechanics (Bristol, Avon)
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