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This study characterised the thigh muscle-tendon unit length variations (MTUv) in elite alpine skiing. MTUv were modelled for seven muscles from knee and hip angles in 17 national team skiers during 1602 cycles (546 Slalom (SL), 908 Giant-Slalom (GS), 136 Super-Giant (SG) and 12 Downhill (DH) cycles). The biarticular rectus femoris showed a dynamic pattern on both legs, especially in SL. On the other side, vastii displayed a stable length on the inside leg in all disciplines (37–46% of the cycle), contrasting with their dynamic behaviour on the outside leg being quasi-static for only 3% (SL) to 27% (DH) of the cycle. SL showed the largest amplitude of MTUv followed by GS, SG and DH. For vastus lateralis, MTUv was ~60%Lr.s−1 in SL but only ~12%Lr.s−1 in DH. In SL, a fine desynchronisation between both joints led to nearly constant MTUv (slow lengthening lasting ~45-51% of the cycle) for the biarticular hamstrings separated by faster variations during turn switch from outside to inside leg. In summary, biarticular MTUv were not characterised by single-joint behaviours, suggesting that extrapolating contraction regimen from knee joint only is not accurate in alpine skiing. [ABSTRACT FROM AUTHOR]

This study aimed to determine the relationship between the torque-generating capacity in sprint cycling and the strength capacity of the six lower-limb muscle groups in male and female world-class sprint cyclists. Eleven female and fifteen male top-elite cyclists performed 5-s sprints at maximal power in seated and standing positions. They also performed a set of maximal voluntary ankle, knee and hip flexions and extensions to assess single-joint isometric and isokinetic torques. Isokinetic torques presented stronger correlations with cycling torque than isometric torques for both body positions, regardless of the group. In the female group, knee extension and hip flexion torques accounted for 81.2% of the variance in cycling torque, while the ability to predict cycling torque was less evident in males (i.e., 59% of variance explained by the plantarflexion torque only). The standing condition showed higher correlations than seated and a better predictive model in males (R2 = 0.88). In addition to the knee extensors and flexors and hip extensors, main power producers, the strength capacity of lower-limb distal plantarflexor (and to a lesser extent dorsiflexor) muscles, as well as other non-measured qualities (e.g., the upper body), might be determinants to produce such extremely high cycling torque in males. [ABSTRACT FROM AUTHOR]

Purpose: To characterize the physiological profiles of elite cross-country mountain-bike (XCO-MTB) cyclists and to examine their pacing and power-output (PO) distribution during international races. Methods: Over 2 competitive seasons, 8 male XCO-MTB cyclists (VO2max 79.9 [5.2] mL·min−1·kg−1, maximal aerobic power [MAP] 411 [18] W and 6.3 [0.4] W·kg−1) regularly undertook incremental tests to assess their PO and heart rate (HR) at first and second ventilatory thresholds (VT1 and VT2) and at VO2max. During the same period, their PO, HR, speed, and cadence were recorded over 13 international races (total of 30 recorded files). Results: Mean PO, speed, cadence, and HR during the races were 283 (22) W (4.31 [0.32] W·kg−1, 68% [5%] MAP), 19.7 (2.1) km·h−1, 68 (8) rpm, and 172 (11) beats·min−1 (91% [2%] HRmax), respectively. The average times spent below 10% of MAP, between 10% of MAP and VT1, between VT1 and VT2, between VT2 and MAP, and above MAP were 25% (5%), 21% (4%), 13% (3%), 16% (3%), and 26% (5%), respectively. Both speed and PO decreased from the start loop to lap 1 before stabilizing until the end of the race.Conclusions: Elite off-road cyclists demonstrated typical values of world-class endurance cyclists with an excellent power-to-mass ratio. This study demonstrated that XCO-MTB races are performed at higher intensities than reported in previous research and are characterized by a fast start followed by an even pace. [ABSTRACT FROM AUTHOR]

Thomas, C, Delfour-Peyrethon, R, Dorel, S, and Hanon, C. Positive effects of pre-exercise metabolic alkalosis on perceived exertion and post-exercise squat jump performance in world-class cyclists. J Strength Cond Res 36(9): 2602–2609, 2022—This study aimed to determine the effects of pre-exercise alkalosis in world-class cyclists on their general (rate of perceived exertion [RPE]) and local (category-ratio scale [CR10]) perceived rates of exertion and acid-base status during 2 types of training sessions. Eight world-class cyclists ingested either sodium bicarbonate (BIC) or a placebo (PLA) in a double-blind and randomized order before performing 4 × 1,000 m constant-power sprints (CP) or 3 × 500 m all-out sprints (AO), with 20 minutes of recovery time between each session. For AO, the performance was assessed through the cycling sprint velocity and a squat jump test during recovery. During both tests, RPE, CR10, and acid-base status were measured. Sodium bicarbonate ingestion was effective in inducing pre-exercise alkalosis, compared with a PLA (p < 0.05). During CP, performance and RPE were the same for BIC and PLA (p > 0.05) with no time effect. The CR10 increased for the last sprint in PLA (p < 0.05) but was attenuated in BIC (BIC: 6 vs. PLA: 8.2; p < 0.05), whereas there was no difference in acid-base status. During AO, RPE and CR10 increased with time, with no BIC effect, whereas blood lactate concentration was different (p < 0.05). Sodium bicarbonate supplementation had no effect on overall repeated sprints (p > 0.05). However, world-class athletes responded to BIC with higher squat jump performance than the PLA condition after AO (p < 0.05). Our results suggest a positive influence of pre-exercise alkalosis in world-class cyclists on local perception of efforts after constant load sprints and an attenuation of muscle power output decline postsprint, as evidenced by improved squat jump performance after all-out cycling effort. [ABSTRACT FROM AUTHOR]

The aims of the present study were to characterize the mechanical output of final road sprints of an elite sprinter during international competitions in relation to his power‐velocity‐endurance characteristics and to investigate the relationship between this sprint performance and the power produced during preceding phases of the race. The sprinter performed a set of short and long sprints (5 to 15‐s) on a cycle ergometer to determine his maximal power‐velocity‐endurance profile. Based on eleven races, the distribution of power throughout each race, peak and mean power (Ppeak and Pmean) and associated pedaling rates (vPpeak and vPmean) during the final sprint were analyzed. The power‐velocity‐endurance profile of the sprinter indicated that his theoeretical mean maximal power and corresponding optimal pedaling rate ranged from 20.0 W.kg−1 (124 rpm) for a 1‐s sprint to 15.0 W.kg−1 (109 rpm) for 20 s. Race data showed that final road sprints were mainly performed on the ascending limb of the power‐velocity relationship (vPpeak, 104 ± 8 and vPmean, 101 ± 8 rpm). Additionally, Ppeak and Pmean were lower than the theoretical maximal power determined from the power‐velocity‐endurance profile (9.9 ± 7.0% and 10.6 ± 9.8%, respectively), which highlighted a significant state of fatigue induced by the race. Finally, sprint power exhibited a high variability between races and was strongly related to the level of power produced during the last minute before the sprint. These findings show the importance of considering both the power‐velocity‐endurance qualities and the power demand of the last lead‐up phase before the sprint in order to optimize final sprint performance. [ABSTRACT FROM AUTHOR]

Purpose: To develop a simple, reliable, and sensitive test to measure stroke performance (ball speed and accuracy) in table tennis. Methods: Fifty-two players were divided into 3 groups in accordance with their level: expert (EG), advanced (AG), and inexperienced (IG). The test consisted of 45 forehand shots where players were asked to reach 3 targets. The test was performed 2 times (separated by 8 min) during the first session (n = 52) to assess intrasession reliability. A second session (n = 28), at least 3 d later, was performed to test intersession reliability. Both speed and accuracy of the ball were measured to evaluate the absolute sensitivity and reliability of the specific test. Results: This study showed good reliability of the specific test for both ball speed and accuracy of EG and AG (ICC range .42-96, CV range 2.0-9.0%). However, the reliability is low for IG. Ball speed and accuracy were greater in EG than in the other groups, and both variables were correlated with the level of the players. Conclusion: Results suggest that the specific test appears to be a simple and sensitive procedure to assess stroke performance in table tennis and that this test could be a relevant tool for coaches in table tennis. [ABSTRACT FROM AUTHOR]