An optimal stroke is essential for winning table tennis competition. The main purpose of this study was to examine the correlations between the stroke characteristics and the stroke effect.
Forty-two young table tennis players were randomly selected from China Table Tennis College (M age = 14.21; M height = 1.57m; M weight = 46.05 kg, right-hand racket, shake-hands grip, no injuries in each joint of the body). The high-speed infrared motion capture system was used to collect the data of stroke characteristics, and the high-speed camera was used to measure the spin speed of the stroke. The influence of stroke characteristics on stroke effect was analyzed.
The time duration of backswing and forward motion were significantly correlated with ball speed (r = -0.403, p < 0.01; r = -0.390, p < 0.01, respectively) and spin speed (r = -0.244, p = 0.027; r = -0.369, p < 0.01, respectively). The ball speed was positively correlated with the linear velocity of right wrist joint (r = 0.298, p < 0.01), anoke had an important correlation with stroke effect, especially the ball speed and spin speed. The movement of the right wrist joint and right ankle joint were mainly correlated with the ball speed of the stroke. The spin speed of the stroke was mainly correlated with the movement of the right wrist joint. click here The placement of the stroke was mainly correlated with the rotation of the right knee joint.
Foot and ankle are some of the most frequently injured places in football players' bodies. Overuse injuries have an insidious onset and can restrain athletes from sports temporary or even permanently. This study aimed to investigate the relationship between the clinical evaluation of the foot and ankle and findings obtained from foot plantar pressure measurements with the development of overuse injury, during the one-year follow-up.
100 licensed football players were included in the study. Presence of joint hypermobility, foot posture assessment, ankle and first metatarsophalangeal joint range of motion measurements, pedobarographic plantar pressure assessment of foot was carried out. Then, the footballers were followed for 12 months for the development of new foot and ankle overuse injuries, and the clinical and pedobarographic data of the footballers with at least one injury were compared with the group without injury.
We found asymmetric pressure distribution between the preferred and non-preferred foot in the group who had an injury in the pedobarographic static foot plantar pressure measurements (p = .040). A statistically significant limitation was found in the ankle eversion, first metatarsophalangeal joint dorsiflexion and ankle plantar flexion degrees in the injured group compared to the uninjured group (p = .029, p = .023, p=.044, respectively).
These findings suggest that impairments in foot plantar pressure distribution and limitations in ankle and foot joint range of motion may be risk factors for the development of foot and ankle overuse injury.
These findings suggest that impairments in foot plantar pressure distribution and limitations in ankle and foot joint range of motion may be risk factors for the development of foot and ankle overuse injury.
The purpose of this study was to compare the effects of combined training of high-volume/low intensity vs. low volume/high intensity on different bio-motor adaptations in sedentary women.
Thirty sedentary healthy females (age, 22.1±3.3 yrs), were randomly assigned into Control group (CG; n=10), High-Volume/low-intensity training group (HV; n=10); or High-Intensity/low-volume training group (HI; n=10). Training protocols were performed during 8 weeks, on 3 non-consecutive days a week.
Post-intervention, there were significant main effects of time and a group by time interaction for all body composition and performance variables (p ≤ 0.001), while no significant differences were found for changes in maximum heart rate. Pairwise comparisons revealed significant decreases in body fat percentage and speed test in HV and HI (p ≤ 0.001) after intervention, while anaerobic power significantly increased in HV and HI (p ≤ 0.001). The rating of perceived exertion (RPE) was significantly superior in HI than HV (p ≤ 0.05). Additionally, there were significant main effects of time and a group by time interaction for all 1-repetition maximum tests (p ≤ 0.001).
Combined interval training and resistance training were effective for improving bio-motor parameters in sedentary young women. HV training produced less RPE than HI training, which may potentially increase adherence to training protocols postintervention.
Combined interval training and resistance training were effective for improving bio-motor parameters in sedentary young women. HV training produced less RPE than HI training, which may potentially increase adherence to training protocols postintervention.
This study evaluated the effects of two types of energy drinks (ED) intake in trained runners.
A double-blind randomized placebo-controlled clinical trial was conducted over 6 weeks. Participants and beverages were allocated by randomization. Twelve men [23 ± 2.6 years, 177 ± 3.4 cm, 74.4 ± 5.5 kg, VO2max = 59.8 ± 5.5 ml·(kg.min)-1] ingested either a conventional energy drink containing carbohydrates and 3 mg·kg-1 of caffeine, (ED1), a sugar-free energy drink 3 mg·kg-1 of caffeine (ED2), or a carbohydrate-containing, decaffeinated placebo (PL) 40-minutes before an exercise protocol. Sprint time, rate of perceived exertion (RPE), respiratory exchange ratio (RER), blood pressure (BP), heart rate and plasmatic glucose were evaluated during the experimental protocol.
Performance improved after consuming both ED (p <0.004 ED1 and p = 0.001 ED2) with lower RPE (p <0.05 for ED1 and p<0.05 for ED2) compared to PL. Consumption of ED2 decreased RER values at 0-5 minutes and 40-45 minutes (p <0.001), and ED1 increased systolic blood pressure (p<0.05) during exercise compared to PL. There were no differences in the evaluated parameters between EDs (p>0.05).
Consumption of conventional or sugar free ED represents a valid ergogenic strategy to improve acute performance with reduction of RPE. However, intake of a conventional ED warrants caution, mainly because the effects on systolic blood pressure.
Consumption of conventional or sugar free ED represents a valid ergogenic strategy to improve acute performance with reduction of RPE. However, intake of a conventional ED warrants caution, mainly because the effects on systolic blood pressure.click here
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