International journal of sports physiology and performance最新文献

Background: Efforts are needed to improve antidoping procedures. The widespread use of power meters among cyclists could help in this regard. However, controversy exists on whether performance monitoring through power-output data could be of help for antidoping purposes.

Purpose: The objective of the present study was to provide insight into the feasibility and utility of implementing power-based performance monitoring in elite cycling. An expert panel of 15 applied sport scientists and professional cycling coaches were asked for their opinions and perspectives on incorporating power data into the antidoping risk-assessment process.

Results: Two different viewpoints were identified from the responses provided by the experts. Some believed that power monitoring could be implemented as an antidoping tool, provided that several surmountable challenges are first addressed. These authors provided suggestions related to the potential practical implementation of such measures. Others, on the contrary, believed that power meters lack sufficient reliability and suggest that the professional cycling world presents conflicts of interest that make this intervention impossible to implement nowadays.

Conclusions: The debate around the utility of power-meter data in the antidoping fight has been ongoing for more than a decade. According to the opinions provided by the experts' panel, there is still no consensus on the real utility and practical implementation of this intervention.

Background and purpose: Cross-country skiing, biathlon, and Nordic combined are Winter Olympics sports that involve cross-country skiing in undulating terrain, characterized by various subtechniques and repeated intensity fluctuations. The stochastic interval profile of these sports necessitates the continuous regulation of work and energy expenditure throughout training sessions and competitions, a concept known as pacing. With the advent of technological advancements that allow for the measurement of these features during training and competitions, scientific studies have broadened our understanding of the associated racing and pacing demands. We provide the current scientific overview of pacing demands in competitive cross-country skiing, biathlon, and Nordic combined and propose guidelines for how performance can be enhanced by adjusting pacing behavior.

Conclusions and practical applications: The study of pacing in skiing has evolved from basic lap-to-lap, or segment, analyses to detailed insights into micropacing strategies. This includes analysis of speed, internal and external power, subtechnique distribution, and associated temporal patterns, combined with subjective ratings of effort. While several objective tools such as heart rate, blood lactate concentration, and speed measurements are widely used in practice, current understanding suggests that these measures should supplement, rather than replace, the use of perceived effort (eg, rating of perceived exertion) to regulate intensity during training and competition in undulating terrain. Therefore, the ability to self-regulate effort appears to be an important performance characteristic and should be developed in adolescents and systematically used to optimize and evaluate the training process and race performance throughout athletes' careers.

Objectives: Assess the effect of water dousing on heat strain and performance during self- and fixed-paced exercise in the heat.

Design: Crossover, block-randomized controlled trial.

Methods: Thirteen trained runners completed a 10-km time trial (TT) and 60-minute fixed-pace run (60% velocity of V˙O2max) in a 30.4 °C, 47.4% relative humidity environment using either water dousing (DOUSE) or no dousing (CON).

Results: Ten-kilometer TT performance was faster in DOUSE compared to CON (44:11 [40:48, 47:34] vs 44:38 [41:21, 47:56] min:s; P = .033). Change in core temperature (Tc) was not different between groups during the TT (+0.02 [-0.04, 0.07] °C in DOUSE; P = .853) or fixed-pace run (+0.02 [-0.15, 0.18] °C; P = .848). Change in mean skin temperature was lower in DOUSE during the TT (-1.80 [-2.15, -1.46] °C; P < .001) and fixed-pace run (-1.38 [-1.81, -0.96] °C; P < .001). Heart rate was lower for DOUSE during the fixed-pace run (-3.5 [-6.8, -0.2] beats/min; P = .041) but not during the TT (-0.2 [-2.5, 2.1] beats/min; P = .853). Thermal sensation was lower for DOUSE during the TT (-49.3 [-72.1, -26.1] mm; P < .001) and fixed-pace run (-44.7 [-59.7, -29.6] mm; P < .001). Rating of perceived exertion was not different between groups for the TT (-0.2 [-0.7, 0.3]; P = .390) or fixed-pace run (-0.2 [-0.8, 0.4]; P = .480). Sweat rate was lower for DOUSE for the TT (-0.37 [-0.53, -0.22] L/h; P < .001) and fixed-pace run (-0.37 [-0.48, -0.26] L/h; P < .001).

Conclusion: Water dousing improves 10-km TT performance in the heat but does not affect Tc. The positive change in thermal perception (via lower skin temperature) during the TT likely drives this benefit.

Purpose: Antarctic expeditions are exceptional physiological challenges. Sleep plays a critical role in athletic performance, recovery, and wellness, with sleep disturbances having a negative impact on health and performance.

Methods: The authors investigated sleep, fatigue, and recovery profiles of the longest solo unsupported one-way polar ski journey across Antarctica. A 33-year-old woman covered 1484.53 km from Hercules Inlet to the South Pole, finishing at the Ross Ice Shelf, in 70 days and 16 hours. Questionnaires on sleep (Pittsburgh Insomnia Rating Scale and Karolinska Sleepiness Scale), fatigue (Subjective Assessment of Fatigue), recovery (Total Quality Recovery), and wellness were completed at different time points (before, during, and after the expedition).

Results: Average daily sleep time was between 4 and 5 hours, increasing to 7 hours for the final part of the expedition. Satisfaction of sleep and lack of energy deteriorated as the expedition progressed, alongside signs of clinical insomnia. Fatigue and muscle soreness increased with increasing milage, with extreme levels and very poor recovery toward the end of the expedition. Despite this, the adventurer continued to perform on extremely high levels. Postexpedition scores returned to baseline, demonstrating the incredible adaptation and ability to recovery. The postexpedition interview showed that prior experience of an Antarctic expedition may have prepared the athlete and made her more resilient for this challenge.

Conclusions: The data provide unique insights into Antarctic expeditions and may help us understand the limits of human performance when planning future expeditions of this nature. Female athletes are capable of extreme challenges, breaking established performance boundaries.

Purpose: The purpose of this study was to investigate the effects of acute ischemic preconditioning (IPC) on tennis skill and physical exercise performance, as well as to explore whether 7-day repeated IPC (RIPC) accelerated fatigue recovery after a simulated tennis match.

Methods: Twenty-nine male tennis-specific current students were randomly allocated into 1 of 2 groups: SHAM (n = 14, 3 × 5 min at 20 mm Hg) and IPC (n = 15, 3 × 5 min at 220 mm Hg). Participants in both groups engaged in acute IPC and RIPC interventions. After the first acute IPC intervention, assessments were conducted to evaluate tennis-specific skills and overall physical exercise capacity. Following completion of chronic RIPC interventions, all participants competed in a simulated tennis match specifically designed to induce fatigue. To evaluate recovery from this induced fatigue, physical exercise capacity tests were conducted at 24 and 48 hours postmatch, allowing for an assessment of the participants' recovery capabilities over time.

Results: After the first acute intervention, notable differences were observed between the IPC and SHAM groups in their performance on the repeated-sprint ability test. Specifically, the total times recorded were significantly shorter in the IPC group compared with the SHAM group (IPC: 109.05 [2.70] vs SHAM: 114.57 [7.45] s, P = .012), and this trend was also reflected in their best times (IPC: 4.20 [0.18] s vs SHAM: 4.39 [0.30] s, P = .042), indicating an immediate benefit of the IPC intervention on sprint performance. After a 7-day RIPC intervention, significant changes were noted in the SHAM group's performance metrics postmatch. There was an increase (P < .001) in fatigue index from 22% (8%) to 30% (9%) during repeated-sprint ability test and a decrease in serve speed from 120.2 (17.5) to 106.7 (13.0) km/h (P = .002) and knee peek torque from 196.0 (49.0) to 162.7 (39) N (extension, 60°/s, P < .001) in the SHAM group 24 hours postmatch, relative to the IPC group. Moreover, compared with the SHAM group, the IPC group showed a lower rate of perceived exertion during the match (P < .001) and a decrease in visual analog scale score (P = .026) 24 hours postmatch, suggesting enhanced recovery and reduced perception of pain relative to the SHAM group.

Conclusion: IPC could serve as a strategy to generate an ergogenic effect and recovery during training and competition.

Purpose: This study compared the physiological profiles and energy-system contributions of trained football players engaged in regular-passing and third-man-passing small-sided games (SSGs) that included 4 versus 4 and a goalkeeper.

Methods: Ten male trained football players participated in this crossover study. All participants were randomly assigned to either regular-passing SSG or third-man-passing SSG (4 vs 4 with a goalkeeper, 35-m × 17-m pitch size, and 6-min match duration). During these SSGs, physiological parameters including peak and mean heart rate, oxygen uptake (V˙O2peak and V˙O2mean), metabolic equivalents in V˙O2peak and V˙O2mean, and blood lactate concentrations (peak La- and delta La- [Δ La-]), were measured. Energy contributions (oxidative [WOxi], glycolytic [WGly], and phosphagen [WPCr] systems) and Global Positioning System (GPS) variables (total distance, total acceleration counts, mean speed, and maximum speed) were also analyzed.

Results: No significant differences in physiological parameters and GPS variables were found between regular- and third-man-passing SSGs. WOxi in kilojoules and percentages was significantly higher during both SSGs than WPCr and WGly (P < .0001, respectively). WPCr and WPCr + WGly values during third-man-passing SSGs were significantly higher than those during regular-passing SSGs (P < .05). Additionally, low to moderate positive correlations were observed between WOxi, WGly in kilojoules, V˙O2peak, V˙O2mean, peak La-, Δ La-, total acceleration counts, and mean speed (r = .39-.64).

Conclusions: Third-man-passing SSGs may be useful for increasing anaerobic capacity. More third-man-passing SSG sessions in preparation for football games may support high metabolic power and repeated powerful anaerobic performances in trained football players.