The Effects of a Complex Training Protocol on Vertical Jump Performance in Male High School Basketball Players

The purpose of this study was to investigate the effects of CT （complex training） on VJ （vertical jump）. It was hypothesized that VJ height would be enhanced through CT and even greater increases would occur as a result of higher intensity resistance exercise. Twenty male high school basketball players were divided into two training groups： a H1 （high intensity）, low repetition group and a medium intensity, HR （high repetition） group. Each training group trained twice per week for six weeks. Training protocols involved three sets of 8-10 squat repetitions （80%-85% 1RM （repetition maximum）） for the HI group followed by ten countermovement jumps and thre.e sets of 12-15 squat repetitions （60%-70% 1RM） for the HR group followed by ten countermovement jumps. A three minute rest period was utilized between each set. Participants were tested at weeks 1, 3, and 6. The results of this study revealed that there was not a significant difference between the two CT protocols with respect to VJ （p = 0.077）. At week 6 both groups increased VJ significantly; HI group （4.0 ±1.8 cm, p 〈 0.01） and the HR group （2.7 ± 1.6 cm, p 〈 0.01）. Within the parameters of this study CT with either HI or HR protocols are effective at improving VJ.

Oscillation Reduction of Breast for Cup-Pad Choice

Traditional studies of evaluating breast displacement included cup fabrics,shoulder straps,and under-bands restricted by own features of sports bras(SBs).The effects of pads on breast support during movement were investigated by conducting trials with the motion capture experiment.The three-dimensional breast displacements at five breast positions were collected and values in the vertical direction were evaluated.Results indicate that the effectiveness of the cup pad depends on the pad diameter and the thickness.SBs with larger pads and thicker pads made of soft polyurethane cause less overall breast displacement during vertical jumping compared to unpadded bras(p<0.05).The effectiveness of bra oscillation reduction was characterized by the total reduced percentage of the breast displacement.These findings enlarge scopes in terms of the current breast displacement analysis and understanding of selecting SBs associated with changes in the specifications of pads,thereby providing objective methods for bra cup evaluation and a design basis for breast protection.

A comparison of lower limb stiffness and mechanical muscle function in ACL-reconstructed,elite,and adolescent alpine ski racers/ski cross athletes

Purpose： The aim of this study was to compare mechanical muscle function in the eccentric/concentric phases of vertical bilateral jumping in anterior cruciate ligament-reconstructed （ACLR）, elite （ELITE）, and adolescent （ADOL） alpine ski racers and ski cross athletes. Methods： Alpine ski racers/ski crossers （ACLR： n = 12, age = 26.7 ± 3.8 years; ELITE： n = 12, age = 23.9 ± 3.0 years; ADOL： n = 12, age = 17.8 ± 0.7 years; females： n = 6 per group, males： n = 6 per group） performed 5 maximal countermovement jumps （CMJs） and 5 squat jumps. The ground reaction forces for each limb were analyzed using dual force plate recording to obtain body center of mass （BCM） velocity, displacement, and power. The eccentric deceleration （ECC） and concentric phases were determined from BCM velocity. CMJ net concentric and ECC impulses were calculated （body mass normalized） along with the peak and mean BCM power and maximal vertical jump height. CMJ lower limb stiffness （LLS） was determined by the slope of the ground reaction forces vs. the BCM displacement curve over the ECC phase. Concentric and ECC asymmetry indices were calculated for each leg, and the left vs. right LLS was compared. Outcome measures （reported as mean ± SD） calculated as a 5-jump mean were normalized to body mass and compared using an analysis of variance. Results： No between-group differences were found for peak and mean power or jump heights. There were no group differences for LLS or net concentric phase impulse, but the net ECC impulse was lower in the ADOL group compared with ELITE skiers （ADOL： 1.33 ± 0.32 Ns/kg; ELITE： 1.59 ± 0.16 Ns/kg; p 〈 0.05）. Although no group differences were found for ECC asymmetry indices, a group × limb interaction was found for LLS （p 〈 0.01）, which was systematically higher in the right vs. the left limb of ADOL skiers （right： 54.1 ± 17.9 N/m/kg; left： 48.7 ± 15.7 N/m/kg;p 〈 0.01）. Conclusion： ADOL skiers demonstrated decreased ECC impulse and systematic right limb dominance in LLS compared with ACLR and ELITE skiers. The implication of these findings for injury and performance are unknown, but further investigation into these potential relationships is warranted.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.

Changes in balance ability,power output,and stretch-shortening cycle utilisation after two high-intensity intermittent training protocols in endurance runners

Purpose：This study aimed to describe the acute effects of 2 different high-intensity intermittent trainings（HIITs） on postural control,countermovement jump（CMJ）,squat jump（SJ）,and stretch-shortening cycle（SSC） utilisation,and to compare the changes induced by both protocols in those variables in endurance runners.Methods：Eighteen recreationally trained endurance runners participated in this study and were tested on 2 occasions：10 runs of 400 m with 90 s recovery between running bouts（10×400 m）,and 40 runs of 100 m with 30 s recovery between runs（40 × 100 m）.Heart rate was monitored during both HIITs;blood lactate accumulation and rate of perceived exertion were recorded after both protocols.Vertical jump ability（CMJ and SJ） and SSC together with postural control were also controlled during both HIITs.Results：Repeated measures analysis revealed a significan improvement in CMJ and SJ during 10 × 400 m（p〈0.05）,whilst no significan changes were observed during 40×100 m.Indexes related to SSC did not experience significan changes during any of the protocols.As for postural control,no significan changes were observed in the 40×100 m protocol,whilst significan impairments were observed during the 10×400 m protocol（p〈0.05）.Conclusion：A protocol with a higher number of shorter runs（40×100 m） induced different changes in those neuromuscular parameters than those with fewer and longer runs（10×400 m）.Whereas the 40×100 m protocol did not cause any significan changes in vertical jump ability,postural control or SSC utilisation,the 10×400 m protocol impaired postural control and caused improvements in vertical jumping tests.

Effects of Hip Thrust Training on the Strength and Power Performance in Collegiate Baseball Players

The aim of the present study was to investigate the effects of hip thrust （HT） training on the strength and power performance of lower extremities. In total, 20 male collegiate baseball players participated in this study and were divided into a HT training group （HTT） and a control group （CON）. Participants in the HTT group added HTT movements to a regular baseball training regimen （3 times per week for 8 weeks）, whereas participants in the CON group only performed the regular baseball training regimen. Before and after the training sessions, strength performance was assessed via tests of squat strength and 3 repetition maximum （3RM） HT strength; power performance was assessed via vertical jump height, standing long jump distance, and 30-m sprint time. The results indicated significant improvement in squat strength （31% ± 15%） and 3RM HT strength （36% ± 16%） （P 〈 0.05）, but not in vertical jump height, standing long jump distance, and 30-m sprint time. Furthermore, the improvement in squat strength highly correlated with 3RM HT strength （r = 0.83, P 〈 0.05）, In conclusion, HTT plays a role in developing squat strength but does not appear to improve power performance.

Video Analysis of Side Hop Technique in Trials

Trials is a specialty of off-road cycling in which the rider has to face obstacle courses without resting feet on the ground. Technique in this sport has a great importance, since it reduces the risk of committing penalties and allows more efficient execution of the gesture. To improve technique, the motion analysis allows to study the gesture both qualitatively and quantitatively. In this work video analysis was used to study the side hop from rear wheel technique. Two different executions of this technique were analyzed. The primary purpose is the identification of the phases that make up the technical gesture. It was given an explanation to the movement strategies adopted in the execution of the jump in the two different situations.

The Effects of a Carbon Fiber Shoe Insole on Athletic Performance in Collegiate Athletes

Sports equipment such as athletic footwear is designed to prevent injury and/or improve performance. There is limited research about the effects of foot orthoses or shoe insoles on performance improvement via enhanced energetics. One possible solution to improve the energy storage and return of athletic footwear is to utilize a carbon fiber shoe insole （CFI） optimally tuned for the human body-footwear system. The purpose of this study was to examine the effects of a CFI on athletic performance. Thirty-four （15 males, 19 females） collegiate athletes performed a vertical jump, a pro agility test, and a 10-yard sprint while wearing normal athletic footwear and footwear incorporating a CFI. Vertical jump height was measured using a commercial Vertec device; pro agility test and 10-yard sprint times were measured using a laser timing system. The use of a CFI resulted in significant improvements in the vertical jump （＋2.5%, p = 0.012） and the 10-yard sprint （＋1.5%, p = 0.020）, but not in the pro agility test. These results demonstrated a CFI can enhance speed/acceleration and power in collegiate athletes. Individual anatomical and biomechanical differences may influence the appropriate CFI stiffness required for each athlete to achieve maximal performance in sports involving running, jumping, and change-of-direction.