Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were administered on each occasion: the Shuttle Sprint Test (SST) for RSA, the Vertical Jump (VJ) for lower body explosive strength (power), and the Interval Shuttle Run Test (ISRT) for interval endurance capacity. Height and weight were measured; body composition was estimated (percent fat, lean body mass). Multilevel modeling of RSA development curve was used with 32 players (16.0±1.7 years) who had two or more observations. The 16 players (16.1±1.8 years) measured on only one occasion were used as a control group to evaluate the appropriateness of the model. Age, lower body explosive strength, and interval endurance capacity significantly contributed to RSA (p < .05). RSA improved with age from 14-17 years (p < .05) and reached a plateau at 17-19 years. Predicted RSA did not significantly differ from measured RSA in the control group (p > .05). The results suggest a potentially important role for the training of lower body explosive strength and interval endurance capacity in the development of RSA among youth basketball players. Age-specific reference values for RSA of youth players may assist basketball coaches in setting appropriate goals for individual players.
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Hop tests are frequently used to determine return to sports (RTS) after anterior cruciate ligament reconstruction (ACLR). Given that bilateral deficits are present after ACLR, this may result in a falsely high limb symmetry index (LSI), since LSI is calculated as a ratio between the values of the limbs.HypothesisAthletes after ACLR would achieve LSI > 90% for the hop test. Secondly, athletes after ACLR demonstrate decreased jump distance on the single hop for distance (SLH) and triple leg hop for distance (TLH) and decreased number of hops for the side hop (SH) for both involved and uninvolved limbs compared to normative data of sex, age and type of sports matched healthy athletes.Materials and MethodsFifty-two patients (38 males mean age 23.9 ±3.5 yrs; 14 females mean age 21.7±3.5 years) who had undergone an ACLR participated in this study. Patients performed the 3 hop tests at a mean time of 7.0 months after ACLR. Hop distance, number of side hops and LSI were compared with normative data of 188 healthy athletes.ResultsThe differences between the involved limb and the uninvolved limb were significant in all hop tests (SLH p=0.003, TLH p=0.003 , SH p=0.018). For females, only significant between limb differences were found in the SLH (p=0.049). For both the SLH and the TLH, significant differences were found between the involved limb and the normative data (males; SLH p<0.001, TLH p<0.001; females; SLH p<0.001, TLH p=0.006) and between the uninvolved limb and the normative data for both males and females (males; SLH p<0.001, TLH p<0.001; females; SLH p=0.003, TLH p=0.038). For the SH, only significant differences were found between the involved limb and the normative values in males (p=0.033).ConclusionAthletes who have undergone an ACLR demonstrate bilateral deficits on hop tests in comparison to age and sex matched normative data of healthy controls. Using the LSI may underestimate performance deficits and should therefore be analyzed with caution when used as a criterion for RTS after ACLR.
Optimizing physical performance is a major goal in current physiology. However, basic understanding of combining high sprint and endurance performance is currently lacking. This study identifies critical determinants of combined sprint and endurance performance using multiple regression analyses of physiologic determinants at different biologic levels. Cyclists, including 6 international sprint, 8 team pursuit, and 14 road cyclists, completed a Wingate test and 15-km time trial to obtain sprint and endurance performance results, respectively. Performance was normalized to lean body mass2/3 to eliminate the influence of body size. Performance determinants were obtained from whole-body oxygen consumption, blood sampling, knee-extensor maximal force, muscle oxygenation, whole-muscle morphology, and muscle fiber histochemistry of musculus vastus lateralis. Normalized sprint performance was explained by percentage of fast-type fibers and muscle volume (R2 = 0.65; P < 0.001) and normalized endurance performance by performance oxygen consumption (V̇o2), mean corpuscular hemoglobin concentration, and muscle oxygenation (R2 = 0.92; P < 0.001). Combined sprint and endurance performance was explained by gross efficiency, performance V̇o2, and likely by muscle volume and fascicle length (P = 0.056; P = 0.059). High performance V̇o2 related to a high oxidative capacity, high capillarization × myoglobin, and small physiologic cross-sectional area (R2 = 0.67; P < 0.001). Results suggest that fascicle length and capillarization are important targets for training to optimize sprint and endurance performance simultaneously.-Van der Zwaard, S., van der Laarse, W. J., Weide, G., Bloemers, F. W., Hofmijster, M. J., Levels, K., Noordhof, D. A., de Koning, J. J., de Ruiter, C. J., Jaspers, R. T. Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body.
