International journal of sports physiology and performance最新文献

Purpose: To compare annual training characteristics and periodization of physical training and shooting between junior, developmental, and elite-level biathletes.

Methods: A retrospective cross-sectional design was used to compare 24 biathletes (12 women) equally distributed across the Norwegian junior (JUN, 20.3 [1.0] y), developmental (DEV, 24.3 [1.3] y), and elite (ELITE, 26.2 [1.6] y) national teams. Inclusion criteria were having a top-10 performance in Junior World Championships, International Biathlon Union Cup, and International Biathlon Union World Cup for the 3 groups, respectively. Training data from the 2021-22 season were categorized by endurance intensity (low- [LIT], moderate-, and high-intensity training), exercise mode, strength, and speed. Shooting data included shots fired during rest, LIT, moderate-intensity training, high-intensity training, and competitions.

Results: Total annual physical training volume was 21% and 14% higher in ELITE (703 [53] h) than JUN (582 [112] h) and DEV (615 [86] h, both P < .05), respectively, mainly due to more LIT and moderate-intensity training (both P < .05). ELITE and DEV performed 37% and 25% more shots than JUN (12,779 [1757] and 11,638 [1782], respectively, vs 9301 [2042]), mainly caused by more shots during LIT (both P < .05). The only differences in annual periodization of physical training and shooting between developmental levels were that ELITE performed higher physical training volumes (17.2 [1.5] vs 13.3 [3.6] h/wk) and fired more shots (377 [70] vs 199 [73] shots/wk) during the general preparation period compared with JUN (both P < .05).

Conclusions: This study provides novel reference data on the training characteristics of high-level biathletes across developmental levels, demonstrating that higher volumes of both physical and shooting-specific training distinguish elite senior athletes from their junior counterparts. However, individual year-to-year progression patterns should be explored in future longitudinal studies.

Purpose: This study examined the external load of different floater types and regular players (RPs) in small-sided games, as well as the effects of low and high inferiority on RPs in professional men's soccer.

Methods: Twenty-four male soccer players from the Greek top-tier league participated in small-sided games over an 8-week in-season period. The games were played without goalkeepers on 4 minigoals, with a 2-touch restriction for inside floaters and a 1-touch restriction for outside floaters. GPS units measured external-load metrics including total distance, high-intensity running distances across speed zones, number and distance covered in sprints, and acceleration/deceleration metrics. Linear mixed-effects models were used to identify differences in external load between floater types and RPs and between games played under low- and high-inferiority conditions for RPs.

Results: RPs showed significant differences in most variables (P < .05) compared with both types of floaters, except for the number of high accelerations and running in the highest velocity band. Inside floaters exhibited higher external load in half of the variables, although these effects diminished in zones of high locomotor and mechanical intensity. External load was higher in low-inferiority games compared with high-inferiority games across all variables (P < .05), except for the number of high decelerations (P = .241).

Conclusions: The results of this study indicate that external load differs between playing roles and inferiority configurations. This information can be utilized by practitioners to optimize training strategies and enhance player performance.

Purpose: A sport-related concussion (SRC) can cause sleep disturbances within 72 hours of injury. However, most research focuses on sleep after >72 hours, with limited attention to acute sleep responses, despite their potential impact on SRC recovery.

Methods: This case study examines a 22-year-old professional rugby union player who sustained an SRC during an away match. Sleep architecture (sleep stages: N1, N2, N3, and rapid eye movement [REM] sleep) and physiological responses during sleep over 4 nights were analyzed-sleep before injury (PRE), the 2 nights immediately following injury (INJ and INJ + 1), and after recovery from injury (POST)-using home-based polysomnography. Return transmeridian travel was undertaken on INJ + 1.

Results: The player took 15 minutes to fall asleep and slept <6 hours on INJ, with reductions in N3 (19% vs 22%-37%) and REM sleep (18% vs 20%-32%) compared with all other nights. Despite increased N3 and REM sleep on INJ + 1, sleep disturbances persisted (23 min to fall asleep, 69 min of wake after sleep onset, 40 awakenings, and sleep efficiency below 85%). Compared with sleep on PRE and POST, mean oxygen saturation and heart-rate variability were lower, mean heart rate was elevated, and respiratory events during sleep were greater on INJ and INJ + 1.

Conclusion: Acute responses after the SRC included sleep disturbances and elevated sympathetic activity (during sleep). The player had difficulty achieving deep, restorative sleep the first night following the SRC, aligning with the non-restorative-sleep complaints commonly reported by concussed athletes on the night(s) immediately following injury.

Purpose: This study aimed to compare the effect of 2 different frequencies of an integral-periodization resistance-training (RT) program on physical performance and incidence of noncontact injury in young trained soccer players during an entire season.

Methods: Forty young trained soccer players (16.6 [0.69] y) were randomly divided into 2 groups: frequency 1 (F1G, n = 18) and frequency 2 (F2G, n = 22). Physical performance was assessed using countermovement jump, progressive loading tests for squat and hip-thrust, 10-m and 30-m sprint tests, the V-Cut test, and the 30-15 Intermittent Fitness Test. Noncontact injuries were also recorded and classified by severity. Both groups performed RT aligned with field-based loads, with F1G completing 1 session/wk and F2G 2 sessions/wk.

Results: The F2G showed significant improvements in all tests, with effect sizes (ES) ranging from 0.40 to 4.35 (all P < .01). The F1G reported significant improvements only in the countermovement jump, squat, hip thrust, and V-Cut tests (ES: 0.54-2.79; all P < .01). The F2G demonstrated significantly greater improvements than the F1G in the squat (ES: 3.41; P < .01), hip thrust (ES: 4.35; P = .006), 10-m sprint (ES: 1.86; P < .001), and 30-m sprint (ES: 1.25; P < .001), along with a significant reduction in injury severity (ES = 0.89; P < .01). No significant differences were found in the countermovement jump, V-Cut, and the 30-15 Intermittent Fitness Test (all P > .05).

Conclusions: Performing 2 RT sessions per week within an integral-periodization model led to superior physical performance improvements and reduced noncontact-injury severity in young trained soccer players compared to 1 session per week.

Purpose: As females have been shown to exhibit greater resistance to fatigue in muscles but lower hypoxia-induced cerebral oxygen saturation during whole-body exercise, this study was conducted to assess their responses to intense cognitive-motor dual-task (CMDT) situations. Recent research has shown that intense CMDT involving whole-body exercise increases neuromuscular fatigue and impairs cognitive performance, both exacerbated in hypoxic conditions.

Methods: Twenty-two healthy young adults (11 females) first performed a session in normoxia, including separated cognitive (CTLCOG), and cycling tasks (CTLEX). This session was followed by 2 CMDT sessions performed in randomized order under normoxia (CMDTNOR) and hypoxia (CMDTHYP). The physical exercise consisted of 20-minute cycling at a "hard" perceived effort, and the cognitive task consisted of a 15-minute Sustained Attention to Response time Task. Psychophysiological measurements included knee-extensor neuromuscular fatigue (peripheral/central fatigue components using femoral nerve electrical stimulation) and prefrontal cortex oxygenation assessed by near-infrared spectroscopy.

Results: Sustained Attention to Response time Task performance was similarly decreased for males and females (P = .32) in CMDTHYP (-6.3% [1.5%], P < .001) and CMDTNOR (-3.9% [1.5%], P = .048) versus CTLCOG. Neuromuscular fatigue was significant postcycling (P < .001), independent of sex (P = .71) and condition (P = .53). Maximal voluntary activation was similarly impaired between sexes (P = .37) in CMDTNOR (-5.8% [0.8%], P < .001) and CMDTHYP (-5.5% [0.8%], P < .001) versus CTLEX. No difference was observed in prefrontal cortex oxygenation during CMDTHYP (P = .23) for either males (44.9% [5.3%]) or females (44.3% [2.7%]).

Conclusion: These findings suggest that intense whole-body CMDTs performed in normoxia and hypoxia negatively impact knee-extensor neuromuscular fatigue, sustained attention, and prefrontal cortex oxygenation, but the effect does not differ between sexes.

Purpose: To assess the effects of cycling cadence, exercise intensity, and preload on blood lactate concentration (BLC), carbohydrate oxidation (CHO), and gross efficiency (GE) during 60-minute cycling sessions.

Methods: Eleven male triathletes (age: 28.2 [9.2] y, height: 179.9 [6.0] cm, body mass: 73.1 [4.8] kg, performance level 3) completed 2 incremental load tests to determine peak power (Ppeak) and 4 prolonged cycling tests including 20-minute warm-up at 40% Ppeak followed by a 20-minute load phase at 60% and 70% Ppeak with a subsequent cooldown at 40% Ppeak, all at 60 and 100 rpm, respectively. BLC, oxygen uptake, and carbon dioxide production were measured, and GE, CHO, and the fraction of oxygen uptake utilized for CHO (relCHO) were calculated.

Results: The higher cadence lowered GE and increased BLC, oxygen uptake, and CHO (P < .05). RelCHO increased with exercise intensity (P < .05), but no cadence-related increase was confirmed. CHO and relCHO were lower (P < .05) at cooldown than at warm-up without changes in BLC.

Conclusions: The lack of evidence for a cadence effect on relCHO supports the suggestion that a higher cadence enables a lower CHO at given metabolic demand and given BLC, particularly at lower exercise intensity. A preload-induced decrease in CHO and relCHO may appear at unchanged availability of pyruvate and lactate as indicated by the BLC. In elite cyclists, where GE remains stable or even improves at higher cadences, the ability to sustain CHO stores by higher cadences could provide a significant performance advantage.

Purpose: This study compared the ingestion of a matched dose (0.3 g·kg-1 BM) of enteric-coated sodium bicarbonate (SB), sodium citrate (SC), and both combined (SBC) on high-intensity exercise performance using a time-to-peak ingestion strategy.

Methods: Ten trained female CrossFit athletes completed four 6-km cycling time trials after consuming either SB, SC, SBC, or a placebo (PLA) in enteric-coated capsules. Blood acid-base balance was measured preingestion, preexercise, and postexercise.

Results: Preexercise blood [HCO3-] was significantly higher in the SB trial compared with the SC (+2.3 [1.8] mmol·L-1, P = .003, g = 1.2) and PLA (+6.5 [1.1 mmol·L-1, P < .0005, g = 2.5) trial. Performance time was faster with SB trials when compared with SC (-11.6 [8.0] s, P = .01), SBC (-17.2 [9.1] s, P = .001), and PLA (-21.5 [14.5] s, P = .007), with no significant difference between SC (mean difference [MD] = 9.9 s, P = .94) and SBC (MD = 4.3, P = 1.0) when compared with PLA. Blood lactate concentration was significantly greater in the SB trial compared with the placebo (MD = 2.4 [2.8] mmol·L-1, P < .001). Preexercise gastrointestinal symptom scores were higher with SB when compared to PLA (MD = 2.4 [3.2] arbitrary units, P = .04) and SC (MD = 2.2 [2.7], P = .032).

Conclusion: Ingestion of 0.3 g·kg-1 BM of SB improved extracellular buffering capacity when compared with SC and PLA, allowing exercise performance improvements.

Purpose: To extract, prioritize, and model the highly conserved variations in mean-maximal power (MMP) data in cyclists utilizing functional principal component (FPC) analysis.

Methods: A 3-parameter model (F3 model) was derived from the first 3 functions identified by FPC analysis of a large MMP data set. The F3 model was assessed for goodness of fit to a reserved out-of-sample partition of the MMP data set. Post hoc external validation was used to test the sensitivity of the second FPC to sprint and endurance bias within published data.

Results: The first 3 FPCs accounted for 97% of the variation in the MMP data. The FPCs were interpretable as gain, sprint-endurance bias, and W' analog functions, respectively. The F3 model showed excellent out-of-sample goodness of fit. FPC2 discriminated between sprint- and endurance-biased data in a post hoc analysis.

Conclusion: FPC analysis is a powerful tool to statistically identify functions that describe the principal modes of variation in MMP data. The identified functions and resulting F3 model show great promise for performance prediction, as well as revealing novel insights into the mechanistic determinants of exercise performance.

Purpose: This study investigated the effects of ischemic conditioning on recovery following high-intensity complex training.

Methods: The study was a randomized controlled trial. Thirty-six participants with at least 1 year of strength-training experience were randomized into 4 groups: control (CON, n = 9), acute ischemic preconditioning (A-IPC, n = 8), repeated ischemic preconditioning (R-IPC, n = 11), and postexercise ischemic conditioning (PEIC, n = 8). CON received no additional intervention. A-IPC and PEIC underwent ischemic conditioning 1 hour before and after training, respectively. R-IPC performed ischemic conditioning for 3 consecutive days, with training conducted 1 hour after the final session. Blood samples and muscle strength were accessed pretraining and at 6, 24, 48, and 72 hours posttraining.

Results: At 6 hours and 24 hours posttraining, R-IPC showed significantly higher countermovement-jump heights (6 h: 45.4 [4.6] cm vs 36.7 [7.0], P = .024; 24 h: 44.4 [3.2] vs 33.8 [7.2] cm, P = .012) and right quadriceps peak torque (6 h: 204.6 [32.8] N vs 145.3 [39.1] N, P = .01; 24 h: 191.2 [48.6] N vs 134.0 [36.6] N, P = .046) versus CON. At 24 hours posttraining, R-IPC had lower CRP than CON (P = .024). R-IPC, A-IPC, and PEIC had higher nitric oxide levels than CON (P = .003, P = .004, P < .001). At 48 hours posttraining, R-IPC, A-IPC, and PEIC exhibited lower CRP levels than CON (P < .001, P < .001, P = .002), R-IPC had lower CRP levels than A-IPC (P = .002).

Conclusions: R-IPC promoted recovery of explosive power and strength while also reducing inflammation and increasing nitric oxide levels. Both A-IPC and PEIC increased nitric oxide levels and reduced inflammation but did not enhance strength recovery.