New tool to assess the force production in the swallow

8 men artistic gymnasts were evaluated with a new test protocol in order to assess isometric strength in an specific hold position on still rings. The proposed test protocol measures the force applied the gymnast on the rings from an initial lying prone position on a force platform while he is trying to achieve the Swallow (or Hirondelle) position. The vertical force (FZ) from the forcetime curve registered (100 Hz) was used and it showed a descent from the initial body weight level caused by the gymnast force on the rings and, later, a maximal isometric force period. Fundamental and derivate variables to extract from the evolution of Fz were defined. Results showed significant statistical differences between gymnasts that could perform the Swallow (P) from those that could not (NP) (pmenor que0.05). Performer gymnasts were characterized by a higher percentage of body weight descent and higher strength in relation to body mass (pmenor que0.05). The practical application of this tool could be to provide coaches with information about how close the gymnast is to perform the Swallow.

Acute effects of endurance exercise on jumping and kicking performance in top-class young soccer players

The aim of this study was to examine the acute effects of endurance exercise on jumping and kicking performance in young soccer players. Twenty-one top-class young soccer players (16.1±0.2 years) performed a countermovement jump test and a maximal instep soccer kick test before and after running for 20 min on a treadmill at 80% of their individual maximum heart rate. Two force platforms were used to obtain the following parameters during the countermovement jump: jump height, maximum power, maximum power relative to body mass, maximum vertical ground reaction force, maximum vertical ground reaction force relative to body mass, and maximum vertical ground reaction force applied to each leg. Maximum vertical ground reaction force and maximum vertical ground reaction force relative to body mass applied to the support leg during the kicks were also calculated with a force platform. The kicking motion was recorded using a three-dimensional motion-capture system. Maximum velocity of the ball, maximum linear velocity of the toe, ankle, knee and hip, and linear velocity of the toe at ball contact during the kicks were calculated. Non-significant differences were found in the parameters measured during the countermovement jump and the maximal instep soccer kick test before and after running, suggesting that the jumping and kicking performances of top-class young soccer players were not significantly affected after 20 min treadmill running at 80% of their individual maximum heart rate.

Analysis of dehidration and strenth in elite badminton players

Background: The negative effects of dehydration on aerobic activities are well established. However, it is unknown how dehydration affects intermittent sports performance. The purpose of this study was to identify the level of dehydration in elite badminton players and its relation to muscle strength and power production. Methodology: Seventy matches from the National Spanish badminton championship were analyzed (46 men?s singles and 24 women?s singles). Before and after each match, jump height and power production were determined during a countermovement jump on a force platform. Participants? body weight and a urine sample were also obtained before and after each match. The amount of liquid that the players drank during the match was also calculated by weighing their individual drinking bottles. Results and Discussion: Sweat rate during the game was 1.1460.46 l/h in men and 1.0260.64 l/h in women. The players rehydrated at a rate of 1.1060.55 l/h and 1.0160.44 l/h in the male and female groups respectively. Thus, the dehydration attained during the game was only 0.3760.50% in men and 0.3260.83% in women. No differences were found in any of the parameters analyzed during the vertical jump (men: from 31.8265.29 to 32.9064.49 W/kg; p.0.05, women: from 26.3664.73 to 27.2564.44 W/kg; p.0.05). Post-exercise urine samples revealed proteinuria (60.9% of cases in men and 66.7% in women), leukocyturia (men = 43.5% and women = 50.0%) and erythrocyturia (men = 50.0% and women = 21.7%). Conclusions: Despite a moderate sweat rate, badminton players adequately hydrated during a game and thus the dehydration attained was low. The badminton match did not cause muscle fatigue but it significantly increased the prevalence of proteinuria, leukocyturia and erythrocyturia.