This study compared EMG activity of young tennis players’ muscles during forehand drives in two groups, GD—those able to raise by more than 150% the vertical velocity of racket-face at impact from flat to topspin forehand drives, and GND, those not able to increase their vertical velocity to the same extent. Upper limb joint angles, racket-face velocities, and average EMGrms values, were studied. At similar joint angles, a fall in horizontal velocity and a rise in racket-face vertical velocity from flat to topspin forehand drives were observed. Shoulder muscle activity rose from flat to topspin forehand drives in GND, but not for drives in GD. Forearm muscle activity reduced from flat to topspin forehand drives in GD, but muscle activation was similar in GND. The results show that radial deviation increased racket-face vertical velocity more at impact from the flat to topspin forehand drives than shoulder abduction.
Isabelle Rogowski, David Rouffet, Frédéric Lambalot, Olivier Brosseau, and Christophe Hautier
Isabelle Rogowski, Gaële Ducher, Olivier Brosseau, and Christophe Hautier
This study aimed at demonstrating the asymmetry in volume between the dominant and nondominant upper limbs in tennis players, controlled for maturity status. Upper limb volumes on both sides were calculated in 72 tennis players and 84 control subjects, using the truncated cone method. The participants’ maturity status was determined using the predicted age at peak height velocity (PHV). The results showed significant larger side-to-side asymmetry in volume in tennis groups than in control groups. These findings suggested that, even before PHV, specific-sport adaptations occurred in the dominant upper limb in tennis players.
Claude Ferrand, Sandra Nasarre, Christophe Hautier, and Marc Bonnefoy
The purpose of this study was to identify the motivational profiles of physically active older adults and to achieve a better understanding of their perceived motives to explain their regular physical activity behavior in relation to self-determination theory (SDT). To address these aims, this study used quantitative and qualitative approaches. Older adults (n = 92; M = 74.95, SD = 4.6) completed the French version of the Sport Motivational Scale. A cluster analysis showed two motivational profiles with differential motivational patterns. The first was named the high combined profile, with high scores on intrinsic motivation and introjected regulation and low levels of external regulation. The second profile was the low to moderate motivational profile, with low scores on intrinsic motivation and moderate scores on introjected regulation. The qualitative study’s results demonstrate the usefulness of SDT in explaining the relationship between these motivational profiles and the intertwining of the three basic psychological needs.
Abderrehmane Rahmani, Georges Dalleau, Fabrice Viale, Christophe A. Hautier, and Jean-René Lacour
This study determined the validity and reliability of the kinematic device developed by Bosco et al. (1995) by comparing its peak force, peak velocity, and peak power measurements to data obtained simultaneously with a force platform placed under the subject’s feet. Fifteen international downhill skiers performed maximal half-squats on a guided barbell with masses of 60–180 kg. The coefficient of correlation (r) between the two peak forces (r = 0.85–0.95, p < .001), the two peak velocities (r = 0.74–0.91, p < .001), and the two peak powers (r = 0.85–0.95, p < .001) indicated that the kinematic device measurements were valid. The trial-to-trial reliability of half-squat exercises measured by the kinematic device gave an intraclass coefficient of correlation (CR) of: 0.70-0.90 for peak force, 0.62-0.90 for peak velocity, and 0.57-0.91 for peak power. There were no statistical differences between the two trials. The standard error of the means (SEM%) was less than 5% for peak force, less than 4% for peak velocity, and less than 7% for power. The high CR and low SEM% indicate that the kinematic device is reliable. The movement recorded by the kinematic device accurately described the action measured by the force platform.
Serge Beliaeff, Danielle R. Bouchard, Christophe Hautier, Martin Brochu, and Isabelle J. Dionne
This cross-sectional study examined the relationship between arm and leg muscle mass and isometric muscle strength in 465 well-functioning women and 439 well-functioning men from the NuAge cohort, age 67–84 years. Leg and arm muscle mass and body fat were measured by dual-X-ray absorptiometry. Maximum voluntary isometric strength of knee extensors and elbow flexors was measured using the belt-resisted method and a handheld dynamometer, respectively. The regression model including leg muscle mass, physical activity level, age, height, and body fat explained 14% of the variance in quadriceps strength in men and 11% in women (p < .001), whereas the model including arm muscle mass and the same covariates elucidated 40% and 28%, respectively, of the variance in biceps strength (p < .001). These results suggest that muscle mass does not play a crucial role in the variations of isometric muscle strength in well-functioning elderly.
Sebastien Racinais, Nadia Gaoua, Khouloud Mtibaa, Rodney Whiteley, Christophe Hautier, and Marine Alhammoud
To determine the effect of cold ambient conditions on proprioception and cognitive function in elite alpine skiers.
22 high-level alpine skiers and 14 control participants performed a proprioceptive-acuity (active movement-extent discrimination) and a cognitive (planning task) test in cold (8°C) and temperate (24°C) ambient conditions.
All participants displayed an increase in thermal discomfort and the amount of negative affects in the cold environment (all P < .05). Average proprioceptive acuity was significantly better in the elite skiers (0.46° ± 0.12°) than in the control group (0.55° ± 0.12°) (P < .05) and was not affected by cold ambient conditions, except for a shift in the pattern of error (over- vs underestimation, P < .05). Cognitive performance was similar between elite skiers and control participants in temperate environments but decreased in the cold in the control group only (P < .05) becoming lower than in elite skiers (P < .05).
Elite alpine skiers showed a significantly better proprioceptive acuity than a control population and were able to maintain their performance during a cognitive task in a cold environment.