Análisis biomecánico del efecto de un aumento del ángulo de salida en el alcance del lanzamiento de peso. (Biomechanics analysis of the influence in the range of the shot-put with increasing release angle.)

Resumen El movimiento realizado por el peso en el aire es un movimiento parabólico que, de acuerdo con las leyes físicas, depende de la velocidad de salida, del ángulo de salida y de la altura inicial. La velocidad de salida es más importante que los otros dos factores. Los ángulos óptimos de salida de los lanzadores profesionales son muy bajos. El motivo es que el cuerpo humano está condicionado para ejercer mayor fuerza con ángulos de salida bajos. El objetivo de este trabajo es el de comprobar si, con un entrenamiento adecuado, es posible condicionar a los atletas para ejercer mayor fuerza con ángulos de salida mayores, mejorando así considerablemente el alcance total. Se ha llevado a cabo una investigación con 12 atletas no experimentados. En el pre-test lanzaron el mismo balón medicinal 30 veces con un rango de ángulos de salida de 25º a 45º. Después de un periodo de entrenamiento de cuatro semanas se llevó a cabo un post-test, similar al inicial. Se realizó un análisis de vídeo en dos dimensiones del mejor lanzamiento de cada sujeto. Se encontraron diferencias significativas en los valores medios de la velocidad de salida, del ángulo de salida y del alcance total, entre el pre-test y el posttest. Las diferencias significativas en la media del ángulo de salida con el que los lanzadores consiguieron sus mejores marcas muestran que el periodo de entrenamiento hizo que los lanzadores desarrollasen más fuerza con ángulos de salida mayores.Palabras clave: lanzamiento de peso; velocidad de salida; altura inicial; ángulo de salida; distancia de vuelo;ángulo óptimo.Abstract The movement made by the shot in the air is a parabolic movement which, according to physical laws, depends on release speed, release angle and initial height. Release speed is more important than the other two factors. Optimum release angles of professional throwers are very low. The reason for this is that human body is conditioned to exert more force with low release angles. The objective of this work is to asses if, with an appropriate training, it is possible to condition the athletes to exert more force at bigger release angles, improving considerably the range of the shot put. A research has been carried out with 12 inexperienced throwers. In the pre-test they threw the same medicinal ball 30 times over a range of release angles from 25º to 45º. After a period of four weeks of training, focused on increasing progressively the release angle, a post-test, similar to the initial one, was carried out. All of the throws were filmed and a 2-D video analysis with the best throw of each thrower in both tests was made. There were significant differences in the average values of release speed,release angle and total range between the pre-test and the post-test. The significant differences in the average release angle with which the throwers obtained their best range show that the period of training made the throwers develop more force at bigger release angles.Key words: shot-put; release speed; initial height; release angle; flight distance; optimal angle

Análisis de la pronación y supinación subastragalinas en la marcha atlética

El calcáneo puede realizar movimientos de inclinación sobre su cara interna (pronación) o externa (supinación). No existe evidencia experimental sobre la relación entre lesiones del miembro inferior, tipo de pie y valores excesivos de pronación o supinación. Tampoco existen estudios concluyentes sobre valores máximos de pronación y supinación durante la carrera o la marcha atlética. Se han formado tres grupos: 5 marchadores, 5 velocistas y 5 sujetos sedentarios. Se ha analizado el tipo de pie (Hernández-Corvo) y la pronación y supinación máximas andando (6 km/h), corriendo (14 km/h) y marchando (12 km/h, únicamente marchadores), en tapiz rodante, mediante filmación 2D posterior. Se ha encontrado correlación negativa significativa (p<0,01) entre valores máximos de pronación y supinación (mayor pronación implica menor supinación y viceversa), pero no entre estos valores y el tipo de pie. No existen diferencias significativas en tipos de pie ni en valores máximos de pronación y supinación entre los tres grupos, aunque de media son los marchadores los que más pronan. Existen diferencias significativas (p<0,05) en valores máximos de pronación y supinación entre velocistas corriendo y marchadores marchando. Esto puede indicar que la técnica de la marcha acentúa la pronación, lo que podría aumentar también el riesgo de lesiones

Anàlisi de la pronació i la supinació subastragalines en la marxa atlètica

El calcani pot realitzar moviments d’inclinació sobre la seva cara interna (pronació) o externa (supinació). No hi ha evidència experimental sobre la relació entre lesions del membre inferior, tipus de peu i valors excessius de pronació o supinació. Tampoc no hi ha estudis concloents sobre valors màxims de pronació i supinació durant la carrera o la marxa atlètica. S’han format tres grups: 5 marxadors, 5 velocistes i 5 subjectes sedentaris. S’ha analitzat el tipus de peu (Hernández-Corvo) i la pronació i supinació màximes caminant (6 km/h), corrent (14 km/h) i marxant (12 km/h, únicament marxadors), en tapís rodador, mitjançant filmació 2D posterior. S’ha trobat correlació negativa significativa (p < 0,01) entre valors màxims de pronació i de supinació (major pronació implica menor supinació i viceversa), però no entre aquests valors i el tipus de peu. No hi ha diferències significatives en tipus de peu ni en valors màxims de pronació i supinació entre els tres grups, encara que de mitjana són els marxadors els que més pronen. Hi ha diferències significatives (p < 0,05) en valors màxims de pronació i de supinació entre velocistes corrent i marxadors marxant. Això pot indicar que la tècnica de la marxa accentua la pronació, la qual cosa podria augmentar també el risc de lesions

Adaptação à prótese híbrida de extremidade superior: estudo termográfico de um caso

O objetivo do estudo foi verificar, por meio de termografia, a adaptação à prótese híbrida de extremidade superior de um sujeito do sexo masculino, 42 anos, amputado proximal de braço esquerdo. Imagens termográficas foram captadas por uma câmara de infravermelho imediatamente após a retirada da prótese, que vinha sendo usada por 8 horas ininterruptas, e 20 minutos de repouso mais tarde, quando foi alcançado equilíbrio térmico em ambiente a 21°C. As imagens foram adquiridas nos planos frontal anterior, sagital direito e esquerdo, tendo sido definidas e analisadas regiões de interesse em cada uma. Os resultados mostram que as temperaturas das regiões avaliadas reduziram-se em média 0,79°C (pThe aim of this study was to assess, by means of thermography, the adaptation to upper-extremity hybrid prosthesis by a male subject, 42 years old, with proximal amputation of left arm. Thermographic images were captured by an infrared camera immediately after prosthesis withdrawal (which had been used for full 8 hours) and 20 minutes later, when thermal balance was reached, in an environment of constant 21°C. Images were captured of frontal and sagittal planes (both right and left), on which seven regions of interest (ROI) were defined and analysed. Results showed that mean ROI temperatures decreased 0.79°C (

Muscle Physiology Changes Induced by Every Other Day Feeding and Endurance Exercise in Mice: Effects on Physical Performance

Every other day feeding (EOD) and exercise induce changes in cell metabolism. The aim of the present work was to know if both EOD and exercise produce similar effects on physical capacity, studying their physiological, biochemical and metabolic effects on muscle. Male OF-1 mice were fed either ad libitum (AL) or under EOD. After 18 weeks under EOD, animals were also trained by using a treadmill for another 6 weeks and then analyzed for physical activity. Both, EOD and endurance exercise increased the resistance of animals to extenuating activity and improved motor coordination. Among the groups that showed the highest performance, AL and EOD trained animals, ALT and EODT respectively, only the EODT group was able to increase glucose and triglycerides levels in plasma after extenuating exercise. No high effects on mitochondrial respiratory chain activities or protein levels neither on coenzyme Q levels were found in gastrocnemius muscle. However, exercise and EOD did increase β-oxidation activity in this muscle accompanied by increased CD36 levels in animals fed under EOD and by changes in shape and localization of mitochondria in muscle fibers. Furthermore, EOD and training decreased muscle damage after strenuous exercise. EOD also reduced the levels of lipid peroxidation in muscle. Our results indicate that EOD improves muscle performance and resistance by increasing lipid catabolism in muscle mitochondria at the same time that prevents lipid peroxidation and muscle damage

Mechanic impact analysis in the prostheses of a bilateral lower-limb amputee during the gait

Observa-se o aumento do uso da acelerometria (medida de impactos) na aplicação clínica, especialmente para estudos da marcha acoplando-se os acelerômetros na tíbia. Entretanto, não se tem observado estudos sobre os efeitos dessas vibrações no sistema locomotor de usuários de prótese do membro inferior. O objetivo deste estudo foi medir a quantidade de impacto durante a marcha de um sujeito amputado bilateral transtibial. As coletas foram realizadas durante a marcha do sujeito caminhando a 4 km/h em uma distância de 8 metros com dois acelerômetros piezoelétricos uniaxiais fixados em dois locais distintos da prótese: inicialmente nos encaixes das próteses e posteriormente fixou-se nas hastes metálicas. Utilizou-se estatística descritiva exploratória com Anova One-Way e Post Hoc de Tukey. Constatou-se diferenças significativas com o teste Anova One-Way entre as 10 aquisições em cada local de fixação do acelerômetro. Através do Post Hoc de Tukey observou-se maiores picos de aceleração no encaixe esquerdo (p < 0,005), indicando uma maior admissão de impacto pelo coto esquerdo que possuía maior comprimento. Os maiores picos de aceleração médio encontrados durante a marcha foram: 3,57g para a prótese direita com o acelerômetro fixado na haste metálica e 5,70g para a prótese esquerda com a fixação no encaixe da prótese. Conclui-se que esta metodologia de avaliação pode ser utilizada para acompanhar o processo de reabilitação protética de sujeitos com amputação de membro inferior.LATELY We can experience the increasing use of accelerometers (Shock measurements) in clinical applications, especially in gait studies attaching the accelerometers in the subjects tibia to impact appraisal. However, there are few studies about the effect of those vibrations in the locomotor system of lower limb prosthetic users. The objective of this study was to measure the amount of vibration during the gait in two different spots in both prostheses of bilateral below-knee amputee. For the acquisition we use a gait speed of 4km/h through 8 meters walk with two uniaxial piezoelectric accelerometers set at two different sites of the prostheses. First, the accelerometers were fixed in both prostheses sockets and later they were fixed in the prostheses pylons. We used descriptive statistics exploratory Anova one-way and post hoc Tukey. The One-way Anova test showed significant differences comparing the accelerometer fixation spots. Through the Tuckey Post Hoc we are able to highlight higher accelerations peaks in the left prosthesis socket (p < 0,005) indicating a higher acceptance of vibration stump left it had greater length. The highest average peak acceleration encountered during the gait were: 3.57 g for the right prostheses with the accelerometer fixed to pylons and 5.70 g for the left prostheses fixed of the prostheses ´sockets. This appraisal approach could be used to monitor the prosthetic rehabilitation process of lower-limb amputees

Effects of vitamin D supplementation on muscle function and recovery after exercise-induced muscle damage: a systematic review

Background: Vitamin D is essential for the optimal health of the skeletal system. However, this vitamin is also involved in other functions of the human body, such as muscle, immune and inflammatory ones. Some studies suggest that adequate levels of vitamin D support muscular function during exercise and accelerate recovery because they reduce specific pro¿inflammatory cytokine levels, but those results have not always been observed. Therefore, this review aims to evaluate the effects of vitamin D supplementation on inflammation, oxidative stress and recovery after exercise. Methods: This systematic review was conducted using the Preferred Reporting of Systematic Reviews and Meta¿Analyses (PRISMA) guidelines. A literature search of SPORTDiscuss, PubMed, Web of Science and Scopus was performed from inception through February 2022. The articles' methodological quality was assessed with the PEDro scale. Results: After the application of the inclusion and exclusion criteria, 11 eligible articles were included. All the studies were considered of moderate methodological quality. Ten studies involved regular vitamin D supplementation for more than 7 days, and one study performed acute vitamin D supplementation 24 h before exercise. Conclusions: The existing evidence suggests that vitamin D supplementation for periods of more than 1 week with a minimum dose of 2000 IU/day appears to be an efficacious strategy for attenuating muscle damage and inflammation after exercise. The potential positive effects on muscle function, muscle pain and oxidative stress need to be confirmed with new investigations. Further research is also required to determine the adequate vitamin D dosage to obtain positive effects without adverse effects.Universidad Pablo de Olavide. Departamento de Deporte e Informátic