Standing long jump and handheld halters; is jumping performance improved?

The purpose of this experimental study was to document the kinematic and dynamic characteristics of the standing long jump without extra loading and with handheld weights (halters) of different mass and to investigate any association between the former and jumpers’ performance. Fifteen subjects (13 males and 2 females) between the ages of 19 and 21 years old participated in this horizontal prospective study. Each participant performed standing long jumps. Regarding the jumping technique, free arm swinging without or with handheld halters of different weights (1.5 kg and 3 kg in each hand) was used. The subjects repeated the jumping set (consisted of free arm swinging jump, jumping with 3 kg and then with 6 kg handheld halters) three times and the three different technique jumps were performed in a random order. The jumping distance was significantly increased 7 cm (2.7%) with 3 kg handheld halters compared to free arm jumps (p=0.006). In addition the subjects jumped 5 cm further with 6 kg handheld weights (2.67±0.27 m) than without (2.62±0.21 m) (statistically significant difference, p=0.005). The horizontal displacement of the center of mass was significantly increased with 3 kg and 6 kg handheld compared to free arm jumps (p=0.007, p=0.005 respectively). Take off angle of center of mass difference was statistically significant between 0 kg (36±5o) and 6 kg (29±5o) handheld weights (12.13% decrease, p=0.001). A gradual significant increase in the horizontal take off velocity of the center of mass was depicted between free arm and 3 kg halters jump (3.5% increase) and 3 kg weights and 6 kg ones (3.69% increase). In conclusion greater distance is achievable during a loaded standing long jump due to 1) horizontal translation of the center of mass, 2) the greater ground reaction force that is generated, 3) decrease in take off angle of center of mass and 4) increase in the horizontal take off velocity of the center of mass

Vrabas. The Effect of Natural and Artificial Grass on Sprinting Performance in Young Soccer Players

Abstract: The sprint performance on natural and artificial grass of 5 th generation was assessed. Sixty eight young male soccer players, which were divided in two groups according to their age [children (n=36; 12.1±0.5y) and adolescents (n=32; 14.2±0.4y)], performed 30-m sprint tests with and without handling the ball on natural and artificial grass. The performance was recorded during 0-10m, 10-30m, and 0-30m running distances. It was found that children were significantly faster during 0-10m running distance on the artificial compared to natural grass when handling the ball while adolescents revealed no differences in sprint performance between the surfaces irrespectively of the ball condition. In running distances 10-30m and 0-30m, children were significant faster in the artificial compared to the natural grass either with or without ball, while the adolescents were significantly faster in the artificial grass only without handling the ball. Children run faster on artificial than natural grass while adolescent soccer players are faster in artificial grass when they do not have to handle the ball. It is clear that children should be more careful when play soccer on artificial grass because the ball is moving faster and greater skill is needed in order to avoid injuries