PURPOSE To verify whether relative age effects (RAEs) occur among young male and female Swiss Alpine skiers of different age groups and performance levels. In addition, the efficacy of normalizing performance in physical tests to height and body mass to attenuate RAEs eventually present was tested. METHODS The Swiss Ski Power Test consists of anthropometric measures and physical tests for coordination and speed, endurance, and strength and has been used since 2004 to evaluate 11- to 19-y-old Swiss competitive Alpine skiers. The authors analyzed the distribution of 6996 tests performed by 1438 male and 1031 female Alpine skiers between 2004 and 2011 according to the athletes' respective relative age quartiles. Differences in anthropometric measures and performance in physical tests according to quartile were assessed, and the possibility of attenuating eventual RAEs on performance by normalization of results to height and body mass was tested. RESULTS RAEs were found among all female and male age groups, with no differences between age groups. While performance level did not affect RAE for male skiers, it influenced RAE among female skiers. RAEs also influenced results in all physical tests except upper-limb strength. Normalization of results to body mass attenuated most RAEs identified. CONCLUSION Small RAEs are present among young Swiss competitive Alpine skiers and should be taken into account in training and selection settings to prevent the waste of possible future talents. When ranking junior athletes according to their performance in physical tests, normalization of results to body mass decreases the bias caused by RAEs.

Purpose. This study explored the effects of unstable shoe design on oxygen consumption. Methods. Oxygen consumption (VO2) and heart rate (HR) were measured in 16 individuals while barefoot, wearing unstable shoes (Masai Barefoot Technology) and wearing conventional sport shoes while standing and walking on a treadmill and for 5 individuals while walking around a 400 m track. Results. When wearing the MBT shoes, a significant (p < 0.01) increase of 9.3 ± 5.2% in VO2 was measured while standing quietly for 6 min. No differences in VO2 and HR were observed between the MBT shoes or weight-adjusted conventional shoes (to match the weight of the MBT shoes) while walking on a treadmill. However, significant increases (p < 0.01) in VO2 (4.4 ± 8.2%) and HR (3.6 ± 7.3%) were observed for the MBT shoes compared with being barefoot. No significant differences in VO2 and HR were recorded while walking around a 400 m track either with MBT shoes, weight-adjusted conventional shoes or barefoot. Nonetheless, a comparison of the MBT shoes with barefoot revealed a tendency for VO2 to be higher when wearing the MBT shoes (7.1 ± 6.5%, p < 0.1) although HR was not significantly affected. Conclusions. The unstable shoe design predominantly effects oxygen consumption while standing, most likely due to increased muscle activity of the lower extremities.

We aimed to manipulate physiological determinants of severe exercise performance. We hypothesized that (1) beta-alanine supplementation would increase intramuscular carnosine and buffering capacity and dampen acidosis during severe cycling, (2) that high-intensity interval training (HIT) would enhance aerobic energy contribution during severe cycling, and (3) that HIT preceded by beta-alanine supplementation would have greater benefits.

The aim of the current review is to discuss applications and mechanism of eccentric exercise in training regimes of competitive sports. Eccentric muscle work is important in most sports. Eccentric muscle contractions enhance the performance during the concentric phase of stretch-shortening cycles, which is important in disciplines like sprinting, jumping, throwing, and running. Muscles activated during lengthening movements can also function as shock absorbers, to decelerate during landing tasks or to precisely deal with high external loading in sports like alpine skiing. The few studies available on trained subjects reveal that eccentric training can further enhance maximal muscle strength and power. It can further optimize muscle length for maximal tension development at a greater degree of extension, and has potential to improve muscle coordination during eccentric tasks. In skeletal muscles, these functional adaptations are based on increases in muscle mass, fascicle length, number of sarcomeres, and cross-sectional area of type II fibers. Identified modalities for eccentric loading in athletic populations involve classical isotonic exercises, accentuated jumping exercises, eccentric overloading exercises, and eccentric cycle ergometry. We conclude that eccentric exercise offers a promising training modality to enhance performance and to prevent injuries in athletes. However, further research is necessary to better understand how the neuromuscular system adapts to eccentric loading in athletes.

Introduction: Supplementation with beta-alanine may have positive effects on severe-intensity, intermittent, and isometric strength-endurance performance. These could be advantageous for competitive alpine skiers, whose races last 45 to 150 s, require metabolic power above the aerobic maximum, and involve isometric muscle work. Further, beta-alanine supplementation affects the muscle force-frequency relationship, which could influence explosiveness. We explored the effects of beta-alanine on explosive jump performance, severe exercise energy metabolism, and severe-intensity ski-like performance. Methods: Nine male elite alpine skiers consumed 4.8 g/d beta-alanine or placebo for 5 weeks in a double-blind fashion. Before and after, they performed countermovement jumps (CMJ), a 90-s cycling bout at 110% VO 2 max (CLT), and a maximal 90-s box jump test (BJ90). Results: Beta-alanine improved maximal (+7 ± 3%, d = 0.9) and mean CMJ power (+7 ± 2%, d = 0.7), tended to reduce oxygen deficit (-3 ± 8%, p = .06) and lactate accumulation (-12 ± 31%) and enhance aerobic energy contribution (+1.3 ± 2.9%, p = .07) in the CLT, and improved performance in the last third of BJ90 (+7 ± 4%, p = .02). These effects were not observed with placebo. Conclusions: Beta-alanine supplementation improved explosive and repeated jump performance in elite alpine skiers. Enhanced muscle contractility could possibly explain improved explosive and repeated jump performance. Increased aerobic energy production could possibly help explain repeated jump performance as well.

High-intensity interval training (HIIT) blocks lasting 1-2 weeks improve the maximal aerobic capacity (VO2max) in trained athletes. The aim of this study was to investigate the effects of a HIIT-block on VO2max, running economy (RE), blood volume (BV) and total haemoglobin mass (tHbm). Fourteen junior soccer players were assigned to intervention (HIIT, n=8) and control (KON, n=6) groups. HUT underwent 13 HUT sessions within ten days. Sessions consisted of four sets of 8x15/15 sec intermittent running and 4x4 min playing small sided games. The target intensity was 90-95% of the maximal heart rate (HRmax). KON underwent a conventional training program. Before, two and seven days after intervention, VO2max, RE, BV and tHbm were assessed. The HIIT group reached lactate levels of 6.6 +/- 1.6 mmol/L and 93.4 +/- 2.2% of HRmax, during intermittent running and lactate levels of 6.1 +/- 2.0 mmol/L and 90.9 +/- 2.1% of HRmax small sided games. There were no significant differences between the three time points in VO2max, RE, BV or tHbm. Our finding that a HIIT block had no effect on VO2max is in contrast to other investigations using the same prescribed intensity but greater overall training volume. Because no changes to tHbm By and VO2max occurred with our intervention, it is not possible to establish a relationship between these variables.

PURPOSE To describe the development of anthropometric and physical characteristics of young Swiss alpine skiers between 2004 and 2011, to compare them between age and performance-level groups, and to identify age- and sex-dependent reference values for the tests performed. METHODS The Swiss-Ski Power Test includes anthropometric measures and physical tests for coordination and speed, strength, anaerobic capacity, and endurance. The authors analyzed the results of 8176 tests performed by 1579 male and 1109 female alpine skiers between 2004 and 2011. Subjects ranged between regional and national level of performance and were grouped according to their competition age groups (U12, 11 y; U14, 12-13 y; U16, 14-15 y; U18, 16-17 y; U21, 18-20 y) and performance level. RESULTS A progressive increase in anthropometric measures and improvements in tests results with increasing age were found. For all tests, male athletes had better results than female athletes. Minor differences were observed in anthropometric characteristics between 2004 and 2011 (mostly <5%), while results of physical and coordinative tests showed significant improvements (up to more than 50% enhancement) or stability over the years. Differences between higher- and lower-level athletes were more pronounced in tests for lower-limb strength and anaerobic capacity. CONCLUSIONS The presented profile of young Swiss alpine skiers highlights the improvements in different physical aspects along the maturation process and chronologically over a period of 7 y. Furthermore, reference values are provided for comparisons with alpine skiers or athletes from other sports.

Alpine ski races can last up to 2.5 minutes and have very high metabolic demands. One limiting factor for performance is insufficient aerobic energy supply. We studied the effects of an 8-day interval training block on aerobic capacity ((V) over doto(2)max) and performance and physiology during the 90-second box jump test (BJ90), a maximal performance test employed to simulate the metabolic demands of alpine ski racing, in elite junior skiers. After 10 high-intensity interval training sessions, performed as cycling, running, or an obstacle course, (V) over doto(2)max increased in all subjects by 2.5 +/- 1.9 ml.minute(-1).kg(-1) (4.3 +/- 3.2%), as did maximal blood lactate concentration in a graded cycling test (before: 11.7 +/- 1.3 mmol.L-1, after: 14.8 +/- 1.8 mmol.L-1, both parameters p < 0.05). Performance (total jumps) and aerobic energy contribution (63.3 +/- 2.8%) during the BJ90 did not increase as hypothesized; however, subjects altered their pacing strategy, which may have counteracted such an effect. Additionally, the present data support the practicality of the performance test used for mimicking the demands of alpine skiing.