Reasons for performing study
Injury to the superficial digital flexor tendon (SDFT) is common in equids, with a high risk of re‐injury associated with changes in tendon stiffness. In vivo measurement ...of limb stiffness has been shown to correlate with tendon stiffness after injury 1 but requires kinematic analysis which is impractical in a clinical setting. We have developed a simple system for measuring limb stiffness statically, which could be used as a tool for monitoring SDFT healing.
Objectives
To validate a goniometric measurement of limb stiffness.
Study design
Cross sectional study.
Methods
Initially, forelimb stiffness indices were determined at the walk for 6 equids using a validated kinematic analysis 1. Limb stiffness indices were then calculated using portable floor scales to record ground reaction force (GRF), and an electrogoniometer to record metacarpophalangeal joint angle. Goniometric limb stiffness indices were subsequently measured in 11 horses ranging from 2 to 20 years of age, with no clinical evidence of SDFT injury. Strength and significance of correlation and agreement between the measurement methods was assessed and association between limb stiffness, limb (left vs. right), weight and age of horse and were calculated.
Results
There were strong positive correlations between GRF and joint angle (R2 = 0.98) and between the static and kinematic methods (R = 0.78, P<0.01). There was a positive correlation between limb stiffness and weight (R2 = 0.85, P<0.01), but no association with age or limb.
Conclusions
This study validated the measurement of limb stiffness in a clinical setting. The positive correlation of limb stiffness and weight supports the theory of an optimised limb spring 2 for energy‐efficient cursorial locomotion which may, in turn, provide a clinically‐relevant measure of running efficiency and therefore the quality of tendon healing post injury.
Ethical animal research: Owner consent was obtained. Source of funding: None. Competing interests: None declared.
Optimizing the technique of successful performance is important for detecting different technique styles that occur in female gymnasts. The aims of this research were to define an optimal kinematic ...model of the Stalder backward to handstand on the uneven bars exercise, as well as factors that most greatly affect the successful performance of the selected exercise, performed at the 39th and 40th World Cups in Artistic Gymnastics in Maribor (SLO). The sample of participants consisted of eight female gymnasts who participated in the Finals and performed the above mentioned exercise. Kinematic parameters were determined by the use of the Ariel Performance APAS 3-D video system, and anthropometric 16 reference points with four body segments (foot, center of gravity of the body-CG, shoulder joint and head). CG was calculated based on the model presented by Winter in 2009. The results of the research defined the kinematic exercise model that requires four phases: 1) Upswing from a handstand position to balance the resistance front; 2) Downswing to upswing with clear support; 3) Lower vertical passing; 4) Swing to handstand position. Variability of the trajectory of referent points is necessary as an indication of the successful performance of the Stalder backward to handstand on the uneven bars technique. In the current research, the variability for the successful technique for CG trajectory values decreases from -0.767m to -1.045m, while the trajectory values of the shoulder point decrease from 0.689m to 0.488m under the axis of rotation. The information given could optimize the performance of other young gymnasts at all levels of performance.
Introduction
Kinematic studies allow the assessment of variations in body position during jumping. This study evaluated changes in kinematic variables in horses during a jumping test.
Methods
Eight ...horses equipped with reflective skin markers were submitted to a jumping test consisting of 70 jumps in 4 series of 10, 15, 20 and 25 times each over a 1.10 m vertical obstacle. Six jumps per series were recorded; a heart rate of ≤ 90 bpm was the criterion to begin the next series. A 25 Hz calibrated camera was placed 10 m from the fence, and 2D images were analyzed. The variables were: overtracking at jumping; take‐off and landing distances; jump length; distance between lowest point of the fore and hind limb and the fence; height of head, withers and croup in relation to the ground when passing the fence; and maximum withers height at jumping. Data were analysed with an ANOVA with a post‐hoc Tukey test (P<0.05).
Results
There was a reduction in take‐off distance (1.65 m to 1.46 m, P = 0.03), landing distance (1.99 m to 1.71 m, P = 0.001), jump length (4.51 m to 4.11 m, P = 0.005), left forelimb distance height above the fence (9.4 cm to 5.1 cm, P = 0.03) and maximum withers height at jumping (2.0 m to 1.95 m, P = 0.001) from the first to the third series. Overtracking before jumping increased from 32 cm to 48 cm (P = 0.003) and there was a reduction of right forelimb height above the fence from 7.3 cm to 2.9 cm (P = 0.04), and of withers and croup height above the fence from 2.0 m to 1.95 m (P = 0.001) and 1.93 m to 1.86 m (P<0.0001) respectively from the first to fourth session.
Conclusions
The increase in the number of jumps resulted in a decrease of take‐off and landing distances, and in the distance between forelimb and fence and the withers and croup height, all indicating decreased jumping efficiency.
Ethical Animal Research
The research was approved by UFRRJ Ethics Committee on Animal Research: UFRRJ/ COMEP‐UFRRJ: 263/2012. Sources of funding: CNPq, CAPES and FAPERJ. Competing interests: none.
The aim of this study was to understand the interactions between anthropometric, kinetic, and kinematic variables and how they determine the 100 m freestyle performance in young swimmers. Twenty‐five ...adolescent swimmers (15 male and 10 female, aged 15.75 ± 1.01 years) who regularly participated in regional and national competitions were recruited. The 100 m freestyle performance was chosen as the variable to be predicted. A series of anthropometric (hand surface area–HSA), kinetic (thrust and active drag coefficient (CDA)), and kinematic (stroke length (SL); stroke frequency (SF), and swimming speed) variables were measured. Structural equation modeling (via path analysis) was used to develop and test the model. The initial model predicted performance with 90.1% accuracy. All paths were significant (p < 0.05) except the thrust—SL. After deleting this non‐significant path (thrust—SL) and recalculating, the model goodness‐of‐fit improved and all paths were significant (p < 0.05). The predicted performance was 90.2%. Anthropometrics had significant effects on kinetics, which had significant effects on kinematics, and consequently on the 100 m freestyle performance. The cascade of interactions based on this path‐flow model allowed for a meaningful prediction of the 100 m freestyle performance. Based on these results, coaches and swimmers should be aware that the swimming predictors can first meaningfully interact with each other to ultimately predict the 100 m freestyle performance.
Despite this growth in the women’s game, there has been a limited amount of research conducted in the women’s rugby league, with assumption made based on insights observed in the men’s game. Video ...coding and 3D analysis was completed, and variables inputted into a generalised linear mixed model (p>0.05) to determine 3D tackle technique categories that estimate inertial head kinematics. If it was observed that ball carrier displayed visual signs of whiplash (i.e., poor head control) it predicted their peak angular and linear head acceleration with the tackle type also predicted the ball carriers peak linear head acceleration.
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