The interaction between constituent year and within‐1‐year effects in elite German youth basketball

The current state of research on relative age effects in basketball shows an uneven picture. These mixed results might be caused by the interaction of constituent year and within‐year effects. Our aim was to examine constituent and within‐1‐year effects in elite German youth basketball. The sample (n = 4400) included players competing in the JBBL (Under‐16 first division) and the NBBL (Under‐19 first division) from 2011/2012 until 2013/2014. A multi‐way frequency analysis revealed an interaction of constituent year effects and within‐1‐year effects for the JBBL, χ²(6, 2590) = 12.76, P < 0.05. NBBL data showed significant constituent year effects, χ²(2, n = 1810) = 25.32, P < 0.01, and within‐1‐year effects for all three age bands but no interaction. The interaction between constituent year and within‐1‐year effects in the JBBL showed reduced within‐1‐year effects with increasing age. Once players enter the system in the JBBL, relatively younger players seem less likely to drop out of the system. Results offer new insight regarding how the regulations of this talent development system may influence athletes' opportunities to enter the system and their likelihood of staying at the highest levels of competition.     

Changes in in vivo knee loading with a variable‐stiffness intervention shoe correlate with changes in the knee adduction moment

External knee adduction moment can be reduced using footwear interventions, but the exact changes in in vivo medial joint loading remain unknown. An instrumented knee replacement was used to assess changes in in vivo medial joint loading in a single patient walking with a variable‐stiffness intervention shoe. We hypothesized that during walking with a load modifying variable‐stiffness shoe intervention: (1) the first peak knee adduction moment will be reduced compared to a subject's personal shoes; (2) the first peak in vivo medial contact force will be reduced compared to personal shoes; and (3) the reduction in knee adduction moment will be correlated with the reduction in medial contact force. The instrumentation included a motion capture system, force plate, and the instrumented knee prosthesis. The intervention shoe reduced the first peak knee adduction moment (13.3%, p = 0.011) and medial compartment joint contact force (12.3%; p = 0.008) compared to the personal shoe. The change in first peak knee adduction moment was significantly correlated with the change in first peak medial contact force (R² = 0.67, p = 0.007). Thus, for a single subject with a total knee prosthesis the variable‐stiffness shoe reduces loading on the affected compartment of the joint. The reductions in the external knee adduction moment are indicative of reductions in in vivo medial compressive force with this intervention. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1548–1553, 2010     

The impact of a 17-day training period for an international championship on mucosal immune parameters in top-level basketball players and staff members

This investigation examined the impact of a 17-d training period (that included basketball-specific training, sprints, intermittent running exercises, and weight training, prior to an international championship competition) on salivary immunoglobulin A (SIgA) levels in 10 subjects (athletes and staff members) from a national basketball team, as a biomarker for mucosal immune defence. Unstimulated saliva samples were collected at rest at the beginning of the preparation for the Pan American Games and 1 d before the first game. The recovery interval from the last bout of exercise was 4 h. The SIgA level was measured using enzyme-linked immunosorbent assay and expressed as absolute concentrations, secretion rate, and SIgA level relative to total protein. The decrease in SIgA levels following training was greater in athletes than in support staff; however, no significant differences between the two groups were detected. A decrease in SIgA level, regardless of the method used to express IgA results, was verified for athletes. Only one episode of upper respiratory tract illness symptoms was reported, and it was not associated with changes in SIgA levels. In summary, a situation of combined stress for an important championship was found to decrease the level of SIgA-mediated immune protection at the mucosal surface in team members, with greater changes observed in the athletes.     

Effects of Sex and Age on Quadriceps and Hamstring Strength and Flexibility in High School Basketball Athletes

BackgroundEccentric hamstring strength and hamstring/quadriceps strength ratios have been identified as modifiable risk factors of hamstring strains. Additionally, those strength and flexibility characteristics are commonly used as clinical tests to monitor progress of athletes with acute or chronic hamstring strains. Although hamstring strains are common among basketball athletes, normative values of knee strength and flexibility characteristics are scarce. Normative values for these athletes would be important in prevention and management of hamstring strains.PurposeTo establish quadriceps and hamstring isokinetic strength and flexibility values among high school basketball athletes and examine the effects of sex and age.Study DesignCross-sectional researchMethodsIsokinetic knee muscular strength (concentric quadriceps [QuadC], concentric hamstring [HamC], eccentric hamstring [HamE], and strength ratios ([HamC/QuadC and HamE/Quad]), flexibility of hip flexors and quadriceps during a Modified Thomas test, and flexibility of hip extensors and hamstring during passive straight leg raise (SLR) and passive knee extension (PKE) tests were measured. Effects of sex and age were analyzed using t-tests and analysis of variance, respectively with Bonferroni corrected post hoc tests (p≤0.01).ResultsA total of 172 high school basketball athletes (64 males/108 females; mean age (range): 15.7 (14-18) years old) participated in the study. Male athletes were significantly stronger than female athletes (QuadC: p<0.001; HamC: p<0.001) while no differences were observed in strength ratio (HamC/QuadC: p=0.759-0.816; HamE/QuadC: p=0.022-0.061). Among male athletes, a significant effect of age on quadriceps and hamstring strength was observed: older male athletes were stronger than younger male athletes. Contrarily, there were no effects of age on strength among female athletes. There were significant sex differences in quadriceps flexibility, SLR, and PKE (female athletes were more flexible; p=0.001-0.005) while no sex differences were found in hip flexor flexibility (p=0.105-0.164). There were no effects of age for any flexibility variables within male and female athletes (p=0.151-0.984).ConclusionThe current results provide normative values for hamstring strength and flexibility in high school basketball athletes. These normative values may further assist sports medicine specialists to develop screening tests, interventions, and return-to-sport criteria in this population.Level of Evidence3B     

贴扎对男子篮球后卫运动员踝关节限制作用的时效性研究

目的:研究踝关节贴扎限制作用的变化趋势,为踝关节贴扎在篮球运动中的实际应用提供依据。方法:选取训练时间均在5年以上的男子篮球后卫运动员10名,二级运动员。以中国国家男子篮球队在北京奥运会上6场比赛统计强度的80%作为实际实验强度,采用图像标记法,测量踝关节贴扎前、后以及每运动10分钟后的踝关节主动和被动背屈、跖屈、内翻、外翻活动度,确定踝关节贴扎失效时间点。结果:贴扎后踝关节活动度(ROM)与贴扎前比较减小(P<0.01);随着运动时间延长,踝关节ROM呈上升趋势;在实验强度下,贴扎后运动30~40分钟后,踝关节ROM与贴扎前比较无显著差异(P>0.05)。结论:踝关节贴扎对踝关节具有保护作用;踝关节贴扎失效的时间范围在运动后30～40分钟,应在半场休息时为运动员踝关节进行二次贴扎,以持续有效地预防踝关节损伤的发生。     

女子篮球运动员大强度训练体液免疫机能的变化

目的　探讨大负荷强度训练与机体免疫机能的关系及其变化规律。方法　对 16名中国大学生篮球联赛(CUBA)女篮运动员进行了纵向跟踪监测 ,观测运动员在赛前大负荷强度训练期间血清IgA、IgM水平的变化。 结果　大负荷强度训练期末和期前血清IgA水平分别为 (1 5 0± 0 35 ) g/L和 (1 80± 0 4 0 ) g/L (P <0 0 5 ) ,与赛前 1周血清IgA水平 (1 97± 0 30 )g/L相比有显著性差异 (P <0 0 5 ) ;IgM分别为 (1 2 7± 0 33) g/L和 (1 5 2± 0 36 ) g/L (P <0 0 5 ) ,与赛前 1周血清IgM水平 (1 4 5± 0 30 ) g/L相比有显著性差异 (P <0 0 5 )。 结论　大负荷强度的运动训练可以导致机体体液免疫—IgA、IgM水平显著下降 ,抑制机体免疫功能     

穿高跟鞋对中青年女性腰椎生理曲度的影响

目的探讨穿高跟鞋对中青年女性腰椎生理曲度的影响。方法对20例健康中青年女性志愿者在穿不同高度的高跟鞋后,摄立位腰椎X线侧位片,测量腰椎曲线指数（LCI）、腰椎前凸度（Cobb角）和骶骨倾斜角（SSA）,并对其进行2 km行走试验调查腰背不适情况。结果高鞋跟组的LCI、Cobb角、SSA明显高于低鞋跟组（P〈0.05）。2 km行走试验后腰背不适情况,60%发生在7 cm以上鞋跟组。结论穿高跟鞋可使腰椎生理曲度增大,易引发腰痛。