Análisis de parámetros biomecánicos durante la recepción en colchonetas y su influencia en los mecanismos de lesión en gimnasia deportiva

RESUMEN Introducción. Entre las acciones técnicas más realizadas en gimnasia deportiva, cabe destacar la recepción sobre la colchoneta, la cual se realiza desde elevadas alturas, generando fuerzas de impacto entre 10 y 18 veces el peso corporal (McNitt-gray. 1993). Pese a la existencia de normas que establecen los criterios a cumplir por una colchoneta, las lesiones durante la recepción tras un salto o salida de un aparato no disminuyen. En este sentido, el Objetivo de esta tesis doctoral fue el de analizar los mecanismos de lesión en gimnasia y su relación con los criterios normativos de las colchonetas. Material y métodos. Los diferentes tipos de estudios planteados fueron: - Estudio de opinión, empleando la metodología QFD (Quality Fuction Deployment) y herramientas como los paneles de usuarios, que han permitido analizar las propiedades y características más importantes de las colchonetas. - Estudio mecánico según norma EN 12503, que han permitido analizar las propiedades de una muestra de colchonetas seleccionadas. - Estudio biomecánico y de percepción de la recepción tras un drop jump modificado en distintos tipos de colchonetas, el cual ha permitido analizar diferentes variables cinéticas y cinemáticas, mediante el empleo de diversas técnicas instrumentales de: electrogoniometría, dinamometría, acelerometría y presurometría. Resultados y discusión. Entre los aspectos más valorados en una colchoneta destacan los materiales rígidos (8.74%) y absorbentes (8.74%), la velocidad de recuperación de la colchoneta (7.57%), y el comportamiento areaelástico de la superficie (6.89%). En los ensayos mecánicos se observa como el comportamiento general de las colchonetas tiende a reducir deceleración y devolución de energía a medida que la deformación aumenta. En los estudios biomecánicos se observa como, siendo los principales mecanismos de lesión las elevadas fuerzas de impacto y la inestabilidad sobre la colchoneta, los resultados mostraron como una deficiente amortiguación de la colchoneta implica al gimnasta realizar una recepción con menores rangos de movimiento articular, soportar elevadas fuerzas de impacto y elevadas magnitudes en las aceleraciones registradas en tibia y cabeza, así como una mayor posibilidad de caída debido al impacto inicial del talón sobre la colchoneta. Ante la falta de estabilidad durante la recepción, asociada con una mayor deformación de la colchoneta, se observa como pese a reducirse las fuerzas de impacto y las aceleraciones en tibia-cabeza, el riesgo de sufrir una lesión se relaciona con el aumento del tiempo empleado por el gimnasta para finalizar la recepción con una mayor presión, flexión y torsión en la zona delantera del pie. Conclusión. Los resultados muestran como no todos los aspectos importantes son analizados por las normas, y como las propiedades de una colchoneta afectan a la cinética y cinemática del gimnasta durante la recepción. La consideración del análisis biomecánico de la recepción por parte de distintas normas podría reducir el elevado número de lesiones asociadas a la inestabilidad en la colchoneta y las elevadas fuerzas de impacto, mejorando a su vez el rendimiento deportivo del gimnasta. ____________________________________________________________________________________________________Introduction. Among the most frecuent skills performed in gymnastics, landing is one of the most importants. Landing from high heights, could generate impact forces between 10-18 body weight (McNitt-gray. 1993). Despite actual mats standards criteria, injuries during landing doesn´t reduce. In this sense, the objective of this doctoral thesis has been to analyze the injury mechanisms in gymnastic and it is relation with mats standards criteria. Material and Methods The different types of studies considered were: - Subjective Study; using QFD (Quality Fuction Deployment) methodology and tools like user´s panel, wich has allowed us to analyze the properties and more important characteristics of mats. - Mechanical study; based on EN 12503, that has allowed us to analyze the properties of a selected sample of mats. - Biomechanical study and the landing percepction after a modified drop jump in diferent mats, wich has allowed us to analyze several instrumental techniques like: Electrogoniometry, dinamometry, accelerometry and pressurometry. Results and discussion Results show that same of the most important characteristics in landing mats are: rigid (8.74%) and absorvents (8.74%) materials, recovery speed (7.57%) and areaelastic behavior surface (6.89%). In normative tests, it is observed that as mats deceleration and energy return is reduced, deformation increases. In landing biomechanical studies, it is observed that inestability and high impact forces are main mechanisms of injury. The results show that a deficient mat deformation implies smaller articular range of motion, high impact forces and accelerations in tibia and head, as well as a greater possibility to fall. Landing inestability, due to a greater deformation of landing mats injury risk is related with the increase of time used by gymnasts to complete the landing, with a greater preassure, flexion and torsion in the forefoot, instead these reduced impact forces and tibial and head accelerations Conclusions Not all important mat aspects are analyzed by the standarized test, because mats properties affect gymnasts kinetic and kinematic during landing. The inclusion of biomechanical landing studys in standard test, could contribute to reduce the high number of injuries associated to inestability and high impact forces during landing, improving gymnasts sport live as well

Effect of the upper material of running shoes on muscle mechanical power transfer on lower limbs

This study focuses on determining the effects of the upper material of running shoes on the mechanical power flows of the muscles of the lower limbs during the support phase of running. Two models of running shoes¿differentiated only by the upper structure and material¿have been used, being randomly assigned to 19 participants. Five measure- ments of each participant per shoe model were obtained at 3.3 m s 1 to perform inverse dynamic analysis with the data obtained. Statistically significant differences have been found between the two models for the muscle power flow variables in the ankle, knee and hip joints, as well as at the ends of adjacent segments. The KNIT-upper model (model 2) presents higher generation (8.87 ± 7.63 W/kg; p < .001; d = -.13) and less absorption ( 5.11 W/kg; p < .001; d = 6.7) of mechanical power in the ankle compared to the MESH-upper model (model 1). The mechanical power flows in the knee and hip indicate that with model 2, greater mechanical power is generated and absorbed by the flexor and extensor muscle groups of these joints compared to model 1 (-.38 ± 2.9 W/kg vs -.22 ± 2.54 W/kg for the knee and 1.75 ± 2.91 W/kg vs 1.15 ± 2.07 W/kg for the hip, respectively). Therefore, it can be concluded that the upper material has an influence on mechanical power flow patterns. However, more studies are needed in order to ac- curately and reliably establish the impact that the upper material of the shoes has on performance and on the prevention of sports injuries

DO SPORT COMPRESSION STOCKINGS IMPROVE COMFORT AND ACCELEROMETRY PARAMETERS IN RUNNERS?

In this study, we analysed accelerometry data from runners foot strikes with and without sport compression stockings. Also, we measured comfort perceived with these garments due its importance to a succesful performance. Ten male runners (n=10) exerted two laboratory test condition in different days: a) without compression stockings and b) with one kind of compression in each leg. Accelerometry data were registered using sensors in tibia and head. Also participants filled out a comfort test in stockings’ condition. Medium compression (MC) impacts attenuation was lower than no compression (NC) condition (p\u3c0,05). General comfort perceived was 66%. In conclusion, compression stockings demonstrated a protective effect against impacts and were perceived as comfortable

COMPRESSION PROFILE OF SPORT COMPRESSION STOCKINGS IN RUNNERS

The purpose of this study was to determine the interface pressure applied using two compressive stockings: medium compression (MC) and strong compression (SC); in three conditions: before, during and after running test. Ten male runners (n=10) exerted two laboratory test condition in different days: a) without compression stockings and b) with one kind of compression in each leg. Interface pressure was registered using PicoPress® device. In both compression conditions, the interface pressure was higher in proximal than distal sensors (MC p\u3c0,05; SC p\u3c0,001). Similar results were taken in dynamic condition, and lower level compression was observed after running test. In conclusion, compressive forces were higher in proximal compared to distal leg area. This is contradictory to the gradual decreasing compression principle

Clustering classification of cyclists according to the acute fatigue outcomes produced by an ultra-endurance event

This study aimed to analyze the differences between clusters obtained by the acute effect of fatigue after an ultra-endurance event in the internal and external load of cyclists. 26 volunteers participated in the study, and they were divided into the experimental group (N = 18; height: 177 ± 8 cm; body mass: 78.6 ± 10.3 kg) and the control group (N = 8; height: 176 ± 10 cm; body mass: 78.0 ± 15.7 kg). The experimental group completed a 12 h non-stop cycling event. Jump height, lactate, plasma antioxidant capacity, pain perception and fatigue perception were measured before and after the event. Cyclists of the experimental group were classified considering their training characteristics (recreational vs. competitive) and by conducting a non-supervised K-means clustering. The differentiation of cyclists according to training characteristics resulted in a lower distance covered by recreational than competitive cyclists (279.4 ± 39.7 km vs. 371.0 ± 71.7 km; ES ≥ 0.8; p 0.05). The clustering analysis provided two clusters. Cluster 2 suffered a greater jump height reduction (-3.3 ± 1.6 vs. 1.2 ± 0.8; ES ≥ 0.8; p < 0.001) and increased pain and fatigue perception (ES ≥ 0.5; p < 0.05) after the race than Cluster 1. In conclusion, counter-movement jump can differentiate the fatigue produced by a cycling ultra-endurance event and therefore, this non-invasive technique is useful in fatigue monitoring and recovery planification

Impact acceleration during prolonged running while wearing conventional versus minimalist shoes.

Purpose: In recent years a sub-group of minimalist runners have emerged who aim to perform physical exercise more naturally in an attempt to reduce running-related injuries. Here we aimed to determine the effect that running with minimalist footwear in a prolonged run has on footimpact accelerations. Method: Seventeen runners ran with minimalist and conventional shoes (MS and CS, respectively) in two separate sessions; the participants had experience with both footwear types. We measured the length and frequency of each stride, as well as the tibial and head impact acceleration every 5 minutes during a prolonged run (30 minutes at 80% of each individual's maximum aerobic speed). Results: There were significant differences in the acceleration rate in the tibia (CS: 516.1 ± 238.47 G/s and MS: 786.6 ± 238.45 G/s; p = .009) and head (CS: 73.3 ± 23.65 G/s and MS: 120.7 ± 44.13 G/s; p = .000). Our data indicate that the type of footwear increased the stride frequency and decreased length and that the impact acceleration is increased with MS compared to CS (p < .05 in both cases). However, the effect of prolonged run was not significantly different between CS and MS (p < .05). Conclusions: The peak tibia acceleration and headtibia acceleration rate indicate that the use of MS may be related to a higher risk of injury. These differences remained independently of the runners' fatigue stat

Effects of central and peripheral fatigue on impact characteristics during running

Fatigue and impact can represent an injury risk factor during running. The objective of this study was to compare the impact transmission along the locomotor system between the central and peripheral fatigued states during running. Tibial and head acceleration as well as shock attenuation in the time- and frequency-domain were analyzed during 2-min of treadmill running in the pre- and post-fatigue state in eighteen male popular runners (N = 18). The impact transmission was measured before and after a 30-min central fatigue protocol on the treadmill or a peripheral fatigue protocol in the quadricep and hamstring muscles using an isokinetic dynamometer. The time-domain acceleration variables were not modified either by peripheral or central fatigue (p > 0.05). Nevertheless, central fatigue increased the maximum (p = 0.006) and total (p = 0.007) signal power magnitude in the high-frequency range in the tibia, and the attenuation variable in the low- (p = 0.048) and high-frequency area (p = 0.000), while peripheral fatigue did not cause any modifications in the frequency-domain variables (p > 0.05). Furthermore, the attenuation in the low (p = 0.000)- and high-frequency area was higher with central fatigue than peripheral fatigue (p = 0.003). The results demonstrate that central fatigue increases the severity of impact during running as well as the attenuation of low and high components

Influence of accelerometer signal filtering on automatic detection of gait impact parameters

[EN] Filtering the signal recorded by an accelerometer is essential to remove noise recorded by the sensor, but in order to calculate gait parameters properly, the choice of a suitable cutoff frequency of the filter is critical. This paper evaluates the influence of the filter cutoff frequency in the calculation of the parameters: vertical peak tibial acceleration and acceleration rate. The accelerometer signal filtering with low-pass filter with cutoff frequency below 50 Hz gives good results in the calculation of peak tibial acceleration but produces estimations of the acceleration rate below its real valueThis work has been sponsored by the Generalitat Valenciana: application 09.02.03.542.50.7 budget line T4015 grant from the “Conselleria de Educación, Cultura y Deporte”, aid for conducting R & D for emerging research groups corresponding to the call set out in Annex IX, the Order 64/2014, of July 31, the “Conselleria de Educación, Cultura y Deporte” (DOCV no. 7.332, of August 5, 2014). Record GV /2015/067.Camacho García, A.; Llinares Llopis, R.; Lucas-Cuevas, Á.; Pérez Soriano, P. (2016). Influence of accelerometer signal filtering on automatic detection of gait impact parameters. International Journal of Advancements in Digital Signal Processing. 3(1). http://hdl.handle.net/10251/94462S3

Relationship between foot eversion and thermographic foot skin temperature after running

[EN] The main instruments to assess foot eversion have some limitations (especially for field applications), and therefore it is necessary to explore new methods. The objective was to determine the relationship between foot eversion and skin temperature asymmetry of the foot sole (difference between medial and lateral side), using infrared thermography. Twenty-two runners performed a running test lasting 30 min. Skin temperature of the feet soles was measured by infrared thermography before and after running. Foot eversion during running was measured by kinematic analysis. Immediately after running, weak negative correlations were observed between thermal symmetry of the rearfoot and eversion at contact time, and between thermal symmetry of the entire plantar surface of the foot and maximum eversion during stance phase (r = −0.3 and p = 0.04 in both cases). Regarding temperature variations, weak correlations were also observed (r = 0.4 and p < 0.05). The weak correlations observed in this study suggest that skin temperature is not related to foot eversion. However, these results open interesting future lines of researchSIDirección General de Investigación Científica y 397 Técnica (DGICT) (DEP2013-48420-P); Ministerio de 398 Educación, Cultura y Deporte (MECD) (Doctoral 399 Fellowship (FPU))

EFFECTS OF TWO DIFFERENT COMPRESSION STOCKINGS IN VENOUS RETURN BEFORE AND AFTER RUNNING

In this study it analyse venous return with different compression stockings (CS). 10 experienced runners ran in two experimental test during 35 minutes in a treadmill at 75% of their maximal aerobic speed. Venous blood flow was measured before/after test with magnetic resonance (RMN). Results indicated that fatigue increased venous blood flow in all conditions (p\u3c0.05), but larger differences were found without stocking condition (WS) (right=1,63 ml/s; left=1,66 ml/s). No significant differences (p\u3e0.05) were found with medium compression stocking (MS). Results suggest that CS didn´t increase venous return and decrease comparing to WS. Nevertheless, if compression stockings lead faster recovery, we couldn’t measure because RMN isn’t faster like other methods