Effect Of Altitude On Muscle Torque And Proprioception In Elite Alpine Skiers

2015 ◽  
Vol 47 ◽  
pp. 605
Author(s):  
Sebastien Racinais ◽  
Marine Alhammoud ◽  
Baptiste Morel ◽  
Violaine Sevrez ◽  
Christophe Hautier
Keyword(s):  
Author(s):  
Agnieszka D. Jastrzębska

This experiment examined changes in body sway after Wingate test (WAnT) in 19 adolescents practicing alpine skiing, subjected to the same type of training load for 4–5 years (10 girls and nine boys). The postural examinations were performed with eyes open (EO), eyes closed (EC), and sway reverenced vision (SRV) in the medial-lateral (ML) and anterior-posterior (AP) planes. The displacement of center of foot pressure (CoP), range of sway (RS), mean sway velocity (MV), way length, and surface area were measured in bipedal upright stance before and after the WAnT to assess the influence of fatigue on postural balance. There were no significant differences in WAnT parameters between girls and boys. Relative peak power (RPP), relative total work (RWtot) were (girls vs. boys) 8.89 ± 0.70 vs. 9.57 ± 1.22 W/kg, p < 0.05 and 227.91 ± 14.98 vs. 243.22 ± 30.24 W/kg, p < 0.05 respectively. The fatigue index (FI) was also on similar level in both genders; however, blood lactate concentration (BLa) was significantly higher in boys (10.35 ± 1.16 mM) than in girls (8.67 ± 1.35 mM) p = 0.007. In the EO examination, statistically significant differences between resting and fatigue conditions in the whole group and after the division into girls and boys were found. In fatigue conditions, significant gender differences were noted for measurements in the ML plane (sway path and RS) and RS in the AP plane. Comparison of the three conditions shows differences between EO vs. EC and SRV in AP plane measured parameters, and for RS in ML plane in rest condition in girls. The strong correlations between FI and CoP parameters mainly in ML plane in the whole group for all examination conditions were noted. By genders, mainly RS in ML plane strongly correlates with FI (r > 0.7). No correlation was found between BLa and CoP parameters (p > 0.06). The presented results indicate that subjecting adolescents of both genders to the same training may reduce gender differences in the postural balance ability at rest but not in fatigue conditions and that girls are significantly superior in postural balance in the ML plane than boys. It was also shown that too little or too much information may be destructive to postural balance in young adolescents.


2007 ◽  
Vol 35 (7) ◽  
pp. 1070-1074 ◽  
Author(s):  
Nicolas Pujol ◽  
Marie Philippe Rousseaux Blanchi ◽  
Pierre Chambat

Background Little is known about the evolution of anterior cruciate ligament injury rates among elite alpine skiers. Purpose To evaluate epidemiologic aspects of anterior cruciate ligament injuries among competitive alpine skiers during the last 25 years. Study Design Descriptive epidemiology study. Methods Data were collected from elite French national teams (379 athletes: 188 women and 191 men) from 1980 to 2005. Results Fifty-three of the female skiers (28.2%) and 52 of the male skiers (27.2%) sustained at least 1 anterior cruciate ligament injury. The overall anterior cruciate ligament injury incidence was 8.5 per 100 skier-seasons. The primary anterior cruciate ligament injury rate was 5.7 per 100 skier-seasons. The prevalence of reinjury (same knee) was 19%. The prevalence of a bilateral injury (injury of the other knee) was 30.5%. At least 1 additional anterior cruciate ligament surgery (mean, 2.4 procedures) was required for 39% of the injured athletes. Men and women were similar with regard to primary anterior cruciate ligament injury rate (P = .21), career remaining after the injury (P = .44), and skiing specialty (P = .5). There were more anterior cruciate ligament injuries (primary, bilateral, reinjuries) among athletes ranking in the world Top 30 (P < .001). Anterior cruciate ligament-injured athletes had a career length of 7.5 years, whereas athletes with no anterior cruciate ligament injury had a career of 4.5 years (P < .001). Finally, injury rates remained constant over time. Conclusion Anterior cruciate ligament injury rates (primary injury, bilateral injury, reinjury) among national competitive alpine skiers are high and have not declined in the last 25 years. Finding a way to prevent anterior cruciate ligament injury in this population is a very important goal.


Author(s):  
Dominique Saragaglia ◽  
J. C. Giunta ◽  
J. Gaillot ◽  
B. Rubens-Duval ◽  
R. Pailhé

2019 ◽  
Vol 40 (05) ◽  
pp. 317-330 ◽  
Author(s):  
Marine Alhammoud ◽  
Baptiste Morel ◽  
Clint Hansen ◽  
Mathew Wilson ◽  
Regis Mecca ◽  
...  

AbstractStandard outcomes of traditional isokinetic testing do not detect differences between various muscle mechanical properties. This study i) explored a novel analysis throughout the range of motion based on statistical parametric mapping and ii) examined the impact of sex and discipline on hamstrings/quadriceps torque in elite alpine skiers. Twenty-eight national team skiers (14 females, 14 males; 14 technical, 14 speed) undertook an isokinetic evaluation of the knee flexors/extensors (range 30–90°, 0° representing full extension). There was no effect of sex (p=0.864, d=0.03) and discipline (p=0.360, d=0.17) on maximal hamstrings-to-quadriceps ratio and no effect of discipline on maximal torque (p>0.156, d≤0.25). Hamstrings torque and hamstrings-to-quadriceps ratio were lower in females than males toward knee extension only (p<0.05). Quadriceps torque was greater after 72° of knee flexion in technicians than downhill skiers (p<0.05). The current data showed that statistical parametric mapping analysis identified angle-specific differences that could not be evidenced when analyzing only maximal torques and reconstructed ratios. This may enhance screening methods to identify pathologic knee function or monitor rehabilitation programs, and inform sex- and discipline-specific training in alpine skiing.


2010 ◽  
Vol 90 (12) ◽  
pp. 1774-1782 ◽  
Author(s):  
Marc Roig ◽  
Janice J. Eng ◽  
Donna L. MacIntyre ◽  
Jeremy D. Road ◽  
W. Darlene Reid

Background The Stair Climb Power Test (SCPT) is a functional test associated with leg muscle power in older people. Objective The purposes of this study were to compare the results of the SCPT in people with chronic obstructive pulmonary disease (COPD) and people who were healthy and to explore associations of the SCPT with muscle strength (force-generating capacity) and functional performance. Design The study was a cross-sectional investigation. Methods Twenty-one people with COPD and a predicted mean (SD) percentage of forced expiratory volume in 1 second of 47.2 (12.9) and 21 people who were healthy and matched for age, sex, and body mass were tested with the SCPT. Knee extensor and flexor muscle torque was assessed with an isokinetic dynamometer. Functional performance was assessed with the Timed “Up & Go” Test (TUG) and the Six-Minute Walk Test (6MWT). Results People with COPD showed lower values on the SCPT (28%) and all torque measures (∼32%), except for eccentric knee flexor muscle torque. In people with COPD, performance on the TUG and 6MWT was lower by 23% and 28%, respectively. In people with COPD, the SCPT was moderately associated with knee extensor muscle isometric and eccentric torque (r≥.46) and strongly associated (r=.68) with the 6MWT. In people who were healthy, the association of the SCPT with knee extensor muscle torque tended to be stronger (r≥.66); however, no significant relationship between the SCPT and measures of functional performance was found. Limitations The observational design of the study and the use of a relatively small convenience sample limit the generalizability of the findings. Conclusions The SCPT is a simple and safe test associated with measures of functional performance in people with COPD. People with COPD show deficits on the SCPT. However, the SCPT is only moderately associated with muscle torque and thus cannot be used as a simple surrogate for muscle strength in people with COPD.


2015 ◽  
Vol 26 (9) ◽  
pp. 2309-2317 ◽  
Author(s):  
A.-M. Liphardt ◽  
J. D. Schipilow ◽  
H. M. Macdonald ◽  
M. Kan ◽  
A. Zieger ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document