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Purpose: The aim of this investigation was to assess alterations of pulmonary oxygen uptake ( V ˙ O 2 ) and muscle deoxygenation on-kinetics during heavy-intensity cycling in youth cyclists over a period of 15 months. Methods: Eleven cyclists (initial age, 14.3 [1.6] y; peak V ˙ O 2 , 62.2 [4.5] mL·min−1·kg−1) visited the laboratory twice on 3 occasions within 15 months. Participants performed an incremental ramp exercise test and a constant workrate test within the heavy-intensity domain during the first visit and second visit, respectively. Subsequently, parameter estimates of the V ˙ O 2 and muscle deoxygenation on-kinetics were determined with mono-exponential models. Results: The V ˙ O 2 phase II time constant decreased from occasion 1 (34 [4] s) to occasion 2 (30 [4] s, P =.005) and 3 (28 [4] s, P =.010). However, no significant alteration was observed between occasions 2 and 3 (P =.565). The V ˙ O 2 slow component amplitude either expressed in absolute values (ie, L·min−1) or relative to end exercise V ˙ O 2 (ie, %) showed no significant changes throughout the study (P =.972 and.996). Furthermore, the muscle deoxygenation on-kinetic mean response time showed no significant changes throughout the study (18 [8], 18 [3], and 16 [5] s for occasions 1, 2, and 3, respectively; P =.279). Conclusion: These results indicate proportional enhancements of local muscle oxygen distribution and utilization, which both contributed to the speeding of the V ˙ O 2 on-kinetics herein. [ABSTRACT FROM AUTHOR]

Purpose: To describe serum irisin and fibroblast growth factor-21 (FGF-21) concentrations in healthy female adolescents with different training activity patterns and their associations with bone mineral properties and metabolic markers. Methods: A total of 62 adolescent girls aged 14–18 years were recruited: 22 rhythmic gymnasts, 20 swimmers, and 20 untrained controls. Bone mineral characteristics by dual-energy X-ray absorptiometry, daily energy intake by dietary recall, serum irisin, FGF-21, undercarboxylated osteocalcin, and C-terminal telopeptide of type I collagen were measured in all girls. Results: Whole body and lumbar spine areal bone mineral density and lumbar spine bone mineral content were higher in the rhythmic gymnasts group compared with swimmers and untrained controls groups (P <.05). Serum irisin, FGF-21, undercarboxylated osteocalcin, and C-terminal telopeptide of type I collagen levels were not significantly different between the groups. In the rhythmic gymnasts group, serum FGF-21 concentration was positively correlated with lumbar spine areal bone mineral density independently of confounding factors (r =.51; P =.027). Conclusions: Serum irisin and FGF-21 levels were not different between adolescent eumenorrheic girls with different training activity patterns. FGF-21 was positively associated with lumbar spine areal bone mineral density, which predominantly consists of trabecular bone in adolescent rhythmic gymnasts. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the training and development process of a multiple-Grand-Slam finalist. Methods: A mixed-methods case-study design was used to capture the quantitative and qualitative aspects related to the training and successful development process. We used a 3-step data-collection process and pragmatic analyses of (1) training history based on logs, plans, and questionnaires; (2) in-depth semistructured interviews with the player's head coach/father, physical coach, and team administrator/mother; and (3) systematic quality assurance through negotiation among researchers and all key informants, including the player. Results: The player's exceptional performance level was achieved by a progressive, nonlinear increase in annual training load during childhood and early youth, stabilizing at 800 sessions and 1250 to 1300 hours per year at the age of 19. The annual tennis-specific training plateaued at ∼750 hours from the age of 15, and 60 to 80 matches were played in most of the analyzed years. Point-play accounted for approximately 50% of the total amount of specific tennis training, clearly ahead of ground strokes (∼30%), serve/return (∼15%), and smash/volley (∼5%). Physical-conditioning hours increased 5-fold from 12 to 19 years, before stabilizing at ∼500 hours at senior age. Key success factors included the athlete's multidimensional sports talent, discipline, and inner drive; a highly dedicated father and tennis-enthusiastic family; and strong support from a complementary and interdisciplinary performance team. Conclusion: This study provides novel information regarding the training and development process for a world-leading tennis player, providing a point of departure for the development of future talents. [ABSTRACT FROM AUTHOR]

Purpose: To compare power output and pacing between maximal 1500- and 2000-m on-water rowing performances. Methods: Twenty-six (female n = 4, male n = 22) international rowers, across 6 boat classes, completed maximal 1500- and 2000-m on-water races, separated by 24 to 48 hours. Crew combinations and seat orders remained consistent between races. Peach PowerLine instrumentation measured power output and stroke rate. Differences in completion time, mean power output (MPO), percentage prognostic velocity (PPV; percentage of world record velocity in each boat class), stroke rate, and pacing variance were assessed using linear mixed modeling. Results: Compared with 2000-m, completion times were 90.4 (6.1) seconds shorter over 1500 m (−24.7% [0.7%]). Both MPO (P =.255, η p 2 =.06) and PPV (P =.340, η p 2 =.18) were not different between distances. Broadly, crews adopted a reverse-J-shaped pacing across both distances, demonstrating a reduced variance over 1500 m (P =.035, η p 2 =.62). Percentage change in MPO from 2000 to 1500 m demonstrated a strong negative association with pacing variance over 1500 m (R2 =.74, P =.027). Conclusions: International rowing crews did not increase MPO or PPV when racing maximally over 1500 m compared to 2000 m. Comparable strategies were adopted over both distances, with less variance in pacing observed over 1500 m. The crews that demonstrated greater increases in MPO over the shorter race employed a flatter pacing strategy. To improve 1500-m on-water performance, rowers may need to adopt a more even pacing approach. [ABSTRACT FROM AUTHOR]

Background: The benefits of oral caffeine intake to enhance several aspects of physical performance, such as aerobic endurance, strength, power, and muscle endurance performance, are well supported. However, how the physical performance benefits of caffeine supplementation are translated into better specific actions in intermittent sports during real or simulated competition has been the topic of fewer investigations, and their results need to be appropriately reviewed and meta-analyzed. Objective: The aim of the study was to investigate the effects of acute caffeine intake on specific actions in intermittent sports involving decision making and high-intensity efforts (eg, team, racket, and combat sports) during real or simulated competitions. Methods: All studies included had blinded and crossover experimental designs, and we conducted a risk-of-bias analysis. In total, we included 24 studies. A meta-analysis was performed using the random-effects model to calculate the standardized mean difference (SMD) estimated by Hedges g and 95% CIs. Results: Caffeine ingestion increased high-intensity sport-specific actions during competition, such as the number of sprints (SMD: 0.48; 95% CI, 0.23–0.74), body impacts (SMD: 0.28; 95% CI, 0.08–0.49), accelerations (SMD: 0.35; 95% CI, 0.06–0.63), decelerations (SMD: 0.63; 95% CI, 0.12–1.14), and high-intensity offensive efforts (SMD: 0.36; 95% CI, 0.11–0.61). Additionally, caffeine ingestion induced a higher positive or success rate of actions during real or simulated competition (SMD: 0.44; 95% CI, 0.19–0.69). Conclusion: The current meta-analysis provides evidence of caffeine supplementation in increasing high-intensity efforts and the success rate of sport-specific actions during real or simulated competition. [ABSTRACT FROM AUTHOR]

Purpose: To compare the training characteristics of an elite team pursuit cycling squad in the 3-month preparation phases prior to 2 successive world-record (WR) performances. Methods: Training data of 5 male track endurance cyclists (mean [SD]; age 23.4 [3.46] y; body mass 80.2 [2.74] kg; 4.5 [0.17] W·kg−1 at LT2; maximal aerobic power 6.2 [0.27] W·kg−1; maximal oxygen uptake 65.9 [2.89] mL·kg−1·min−1) were analyzed with weekly total training volume by training type and heart rate, power output, and torque intensity distributions calculated with reference to the respective WRs' performance requirements. Results: Athletes completed 805 (82.81) and 725 (68.40) min·wk–1 of training, respectively, in each season. In the second season, there was a 32% increase in total track volume, although track sessions were shorter (ie, greater frequency) in the second season. A pyramidal intensity distribution was consistent across both seasons, with 81% of training, on average, performed below LT1 power output each week, whereas 6% of training was performed above LT2. Athletes accumulated greater volume above WR team pursuit lead power (2.4% vs 0.9%) and torque (6.2% vs 3.2%) in 2019. In one athlete, mean single-leg-press peak rate of force development was 71% and 46% higher at mid- and late-phases, respectively, during the preparation period. Conclusions: These findings provide novel insights into the common and contrasting methods contributing to successive WR team pursuit performances. Greater accumulation of volume above race-specific power and torque (eg, team pursuit lead), as well as improved neuromuscular force-generating capacities, may be worthy of investigation for implementation in training programs. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to quantify training and match-day (MD) load during 3-, 4-, and 5-day microcycles in professional adult football, as well as to analyze the effect of the microcycle length on training load produced the day after the match (MD + 1) and the day before the match (MD − 1). Methods: The study involved 20 male professional football players whose external and internal loads were monitored for a whole season. The training exposure, total distance covered, high-speed-running distance, sprint distance (SD), individual SD above 80% of the individual maximum velocity (D > 80%), and the number of accelerations and decelerations were quantified, as well as rating of perceived exertion and session rating of perceived exertion training load. Results: Microcycle length affected most of the variables of interest: high-speed-running distance (F = 9.04, P <.01), SD (F = 13.90, P <.01), D > 80% (F = 20.25, P <.01), accelerations (F = 10.12, P <.01), and decelerations (F = 6.01, P <.01). There was an interaction effect between the training day and microcycle type for SD (F = 5.46, P <.01), D > 80% (F = 4.51, P <.01), accelerations (F = 2.24, P =.06), and decelerations (F = 3.91, P <.01). Conclusions: Coaches seem to be influenced by shorter microcycles in their training proposal, preferring sessions with a reduced muscle impact during shorter microcycles. Independent of the length of the congested fixture microcycle, the daily load seems to decrease when MD approaches. [ABSTRACT FROM AUTHOR]

Purpose: To profile the training characteristics of an elite team pursuit cycling squad and assess variations in training intensity and load accumulation across the 36-week period prior to a world-record performance at the 2018 Commonwealth Games. Methods: Training data of 5 male track endurance cyclists (mean [SD]; age 21.9 [3.52] y; 4.4 [0.16] W·kg−1 at anaerobic threshold; 6.2 [0.28] W·kg−1 maximal oxygen uptake 68.7 [2.99] mL kg·min−1) were analyzed with weekly total training volume and heart rate, power output, and torque intensity distributions calculated with reference to their 3:49.804 min:s.ms performance requirements for a 4-km team pursuit. Results: Athletes completed 543 (37) h−1 of training across 436 (16) sessions. On-bike activities accounted for 69.9% of all training sessions, with participants cycling 11,246 (1139) km−1 in the training period of interest, whereas 12.7% of sessions involved gym/strength training. A pyramidal intensity distribution was evident with over 65% and 70% of training, respectively, performed at low-intensity zone heart rate and power output, whereas 5.3% and 7.7% of training was performed above anaerobic threshold. The athletes accumulated 4.4% of total training volume at, or above, their world-record team pursuit lead position torque (55 N·m). Conclusions: These data provide updated and novel insight to the power and torque demands and load accumulation contributing to world-record team pursuit performance. Although the observed pyramidal intensity distribution is common in endurance sports, the lack of shift toward a polarized intensity distribution during taper and competition peaking differs from previous research. [ABSTRACT FROM AUTHOR]

Purpose: To compare designs of training sessions applied by world-class cross-country skiers during their most successful junior and senior season. Methods: Retrospective analysis of self-reported training characteristics (ie, training form, intensity, and exercise mode) among 8 male and 7 female world-class cross-country skiers was conducted. Results: Total number of sessions (441 [71] vs 519 [34], P <.001, large effect) and mean duration (1.5 [0.1] h vs 1.7 [0.1] h, P <.001, moderate effect) increased from junior to senior age. More double-session days were performed at senior age (124 [50] vs 197 [29] d, P <.001, large). The number (310 [64] vs 393 [64], P <.001, large effect) and duration (1.3 [0.1] h vs 1.5 [0.1] h, P <.001, moderate effect) of low-intensity training sessions increased from junior to senior age. Regarding intensive training, most emphasis was put on high-intensity training sessions lasting 20 to 39 minutes with <5-minute intervals at junior age, while 40 to 59 minutes of moderate-intensity training with 5- to 9-minute intervals was predominant at senior age. More MIXED (combined moderate- and high-intensity) sessions (9 [7] vs 14 [7], P =.023, moderate effect) and longer races (0.5 [0.1] h vs 0.6 [0.1] h, P = 0.29, moderate effect) compensated for fewer high-intensity training sessions at senior age (36 [17] vs 25 [10], P =.027, moderate effect). Duration of strength-training sessions increased significantly (0.6 [0.1] vs 0.8 [0.2] h, P = 0.30, moderate effect), while other training forms remained unchanged. Conclusions: World-class cross-country skiers increased their training volume from junior to senior age primarily by more and longer low-intensity training sessions and more often training twice per day. Concurrently, the most frequent intensive sessions were modified from high- to moderate-intensity training, lasted longer, and contained longer intervals. [ABSTRACT FROM AUTHOR]

The main objective of this placebo-controlled, triple-blind, balanced crossover study was to assess the acute effects of phenylcapsaicin (PC) intake (2.5 mg) on intraocular pressure (IOP), ocular perfusion pressure (OPP), and heart rate (HR) during a 30-min cycling task performed at 15% of the individual maximal power. Twenty-two healthy young adults performed the cycling task 45 min after ingesting PC or placebo. IOP was measured with a rebound tonometer before exercise, during cycling (every 6 min), and after 5 and 10 min of recovery. OPP was assessed before and after exercise. HR was monitored throughout the cycling task. We found an acute increase of IOP levels related to PC consumption while cycling (mean difference = 1.91 ± 2.24 mmHg; p =.007, η p 2 =.30), whereas no differences were observed for OPP levels between the PC and placebo conditions (mean difference = 1.33 ± 8.70 mmHg; p =.608). Mean HR values were higher after PC in comparison with placebo intake (mean difference = 3.11 ± 15.87 bpm, p =.019, η p 2 =.24), whereas maximum HR did not differ between both experimental conditions (p =.199). These findings suggest that PC intake before exercise should be avoided when reducing IOP levels is desired (e.g., glaucoma patients or those at risk). Future studies should determine the effects of different ergogenic aids on IOP and OPP levels with other exercise configurations and in the long term. [ABSTRACT FROM AUTHOR]

Postexercise hydration is fundamental to replace fluid loss from sweat. This study evaluated rehydration and gastrointestinal (GI) symptoms for each of three beverages: water (W), sports drink (SD), and skimmed, lactose-free milk (SLM) after moderate-intensity cycling in the heat. Sixteen college students completed three exercise sessions each to lose ≈2% of their body mass. They drank 150% of body mass loss of the drink assigned in randomized order; net fluid balance, diuresis, and GI symptoms were measured and followed up for 3 hr after completion of fluid intake. SLM showed higher fluid retention (∼69%) versus W (∼40%; p <.001); SD (∼56%) was not different from SLM or W (p >.05). Net fluid balance was higher for SLM (−0.26 kg) and SD (−0.42 kg) than W (−0.67 kg) after 3 hr (p <.001), resulting from a significantly lower diuresis with SLM. Reported GI disturbances were mild and showed no difference among drinks (p >.05) despite ingestion of W (1,992 ± 425 ml), SD (1,999 ± 429 ml), and SLM (1,993 ± 426 ml) in 90 min. In conclusion, SLM was more effective than W for postexercise rehydration, showing greater fluid retention for the 3-hr follow-up and presenting with low-intensity GI symptoms similar to those with W and SD. These results confirm that SLM is an effective option for hydration after exercise in the heat. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to analyze the reliability and validity of the predicted distance–time relationship in the severe-intensity domain from a 3-minute all-out running test (3MT). Methods: Twelve runners performed two 3MTs (test #1 and test #2) on an outdoor 400-m track after familiarization. Eighteen-hertz Global Positioning System data were used to estimate critical speed (CS) and distance covered above CS (D′). Time to cover 1200 and 3600 m (T1200 and T3600, respectively) was predicted using CS and D′ estimates from each 3MT. Eight runners performed 2 time trials in a single visit to assess real T1200 and T3600. Intraclass correlation coefficients (ICCs) and standard errors of measurement were calculated for reliability analysis. Results: Good to excellent reliability was found for CS, T1200, and T3600 estimates from 3MT (ICC >.95, standard error of measurement between 1.3% and 2.2%), and poor reliability was found for D′ (ICC =.55, standard error of measurement = 27%). Predictions from 3MT were significantly correlated to actual T1200 (r =.87 and.85 for test #1 and test #2, respectively) and T3600 (r =.91 and.82 for test #1 and test #2, respectively). The calculation of error prediction showed a systematic error between predicted and real T3600 (6.4% and 7.8% for test #1 and test #2, respectively, P <.01) contrary to T1200 (P >.1). Random error was between 4.4% and 6.1% for both distances. Conclusions: Despite low reliability of D′, 3MT yielded a reliable predicted distance–time relationship allowing repeated measures to evidence change with training adaptation. However, caution should be taken with prediction of performance potential of a single individual because of substantial random error and significant underestimation of T3600. [ABSTRACT FROM AUTHOR]

Purpose: Training characteristics such as duration, frequency, and intensity can be manipulated to optimize endurance performance, with an enduring interest in the role of training-intensity distribution to enhance training adaptations. Training intensity is typically separated into 3 zones, which align with the moderate-, heavy-, and severe-intensity domains. While estimates of the heavy- and severe-intensity boundary, that is, the critical speed (CS), can be derived from habitual training, determining the moderate–heavy boundary or first threshold (T1) requires testing, which can be costly and time-consuming. Therefore, the aim of this review was to examine the percentage at which T1 occurs relative to CS. Results: A systematic literature search yielded 26 studies with 527 participants, grouped by mean CS into low (11.5 km·h−1; 95% CI, 11.2–11.8), medium (13.4 km·h−1; 95% CI, 11.2–11.8), and high (16.0 km·h−1; 95% CI, 15.7–16.3) groups. Across all studies, T1 occurred at 82.3% of CS (95% CI, 81.1–83.6). In the medium- and high-CS groups, T1 occurred at a higher fraction of CS (83.2% CS, 95% CI, 81.3–85.1, and 84.2% CS, 95% CI, 82.3–86.1, respectively) relative to the low-CS group (80.6% CS, 95% CI, 78.0–83.2). Conclusions: The study highlights some uncertainty in the fraction of T1 relative to CS, influenced by inconsistent approaches in determining both boundaries. However, our findings serve as a foundation for remote analysis and prescription of exercise intensity, although testing is recommended for more precise applications. [ABSTRACT FROM AUTHOR]

Purpose: To examine associations between exercise heart rate (HRex) during a continuous-fixed submaximal fitness test (CF-SMFT) and an intermittent-variable protocol (semistandardized kicking drill [SSD]) in Australian Football athletes, controlling for external intensities, within-session scheduling, and environmental conditions. Methods: Forty-four professional male Australian Football athletes (22.8 [8.0] y) were monitored over 10 sessions involving a 3-minute CF-SMFT (12 km·h−1) as the first activity and a SSD administered 35.7 (8.0) minutes after the CF-SMFT. Initial heart rate and HRex were collected, with external intensities measured as average velocity (in meters per minute) and average acceleration–deceleration (in meters per second squared). Environmental conditions were sampled. A penalized hierarchical linear mixed model was tuned for a Bayesian information criterion minima using a 10-fold cross-validation, with out-of-sample prediction accuracy assessed via root-mean-squared error. Results: SSD average acceleration–deceleration, initial heart rate, temperature, and ground hardness were significant moderators in the tuned model. When model covariates were held constant, a 1%-point change in SSD HRex associated with a 0.4%-point change in CF-SMFT HRex (95% CI, 0.3–0.5). The tuned model predicted CF-SMFT HRex with an average root-mean-squared error of 2.64 (0.57) over the 10-fold cross-validation, with 74% and 86% of out-of-sample predictions falling within 2.7%-points and 3.7%-points, respectively, from observed values, representing the lower and upper limits for detecting meaningful changes in HRex according to the documented typical error. Conclusions: Our findings support the use of an SSD to monitor physiological state in Australian Football athletes, despite varied scheduling within session. Model predictions of CF-SMFT HRex from SSD HRex closely aligned with observed values, considering measurement imprecision. [ABSTRACT FROM AUTHOR]

Purpose: Without appropriate standardization of exercise doses, comparing high- (HI) and low-intensity (LI) training outcomes might become a matter of speculation. In athletic preparation, proper quantification ensures an optimized stress-to-recovery ratio. This review aims to compare HI and LI doses by estimating theoretically the conversion ratio, 1:x, between HI and LI: How many minutes, x, of LI are equivalent to 1 minute of HI using various quantification methods? A scrutinized analysis on how the dose increases in relation to duration and intensity was also made. Analysis: An estimation was conducted across 4 categories encompassing 10 different approaches: (1) "arbitrary" methods, (2) physiological and perceptual measurements during exercise, (3) postexercise measurements, and comparison to (4a) acute and (4b) chronic intensity-related maximum dose. The first 2 categories provide the most conservative estimation for the HI:LI ratio (1:1.5–1:10), and the third, slightly higher (1:4–1:11). The category (4a) provides the highest estimation (1:52+) and (4b) suggests 1:10 to 1:20. The exercise dose in the majority of the approaches increase linearly in relation to duration and exponentially in relation to intensity. Conclusions: As dose estimations provide divergent evaluations of the HI:LI ratio, the choice of metric will have a large impact on the research designs, results, and interpretations. Therefore, researchers should familiarize themselves with the foundations and weaknesses of their metrics and justify their choice. Last, the linear relationship between duration and exercise dose is in many cases assumed rather than thoroughly tested, and its use should be subjected to closer scrutiny. [ABSTRACT FROM AUTHOR]

Introduction: Physical activity and exercise are protective factors for physical and cognitive decline in older adults, but recent studies reveal that a large percentage of this population do not practice exercise at the levels recommended by international guidelines. The frequency, intensity, type, time, volume, and progression (FITT-VP) principles are a widely used method for prescribing physical exercise, allowing the development of a personalized exercise program that meets the needs of each individual. Objectives: This masterclass is intended to serve as a professional application tool for physical therapists who prescribe physical exercise for older adults. We present a section for each FITT-VP principle to facilitate handling these principles individually when prescribing exercise for this population. Methods: Review of the scientific literature and international guidelines on the prescription of physical exercises for older adults. Results: Aerobic, mobility, resistance, balance, and flexibility exercises, as well as functional training, should be included in an exercise program for older adults, which should be progressed using different methods for each of the exercise modalities. Conclusions: An exercise program for older adults should integrate different exercise modalities. Exercise progression should be performed following the FITT-VP principles and some specific progression factors recommended for each exercise modality. Significance: Considering the challenge faced by clinicians in designing a viable exercise program for older adults that responds to international recommendations, with this masterclass we hope to help physical therapists to plan an exercise program that is feasible and at the same time, responds to the expected needs of this population. [ABSTRACT FROM AUTHOR]

Context: Patellofemoral pain (PFP) is a prevalent chronic condition characterized by retropatellar or peripatellar pain exacerbated by various knee flexion-based activities. Previous research has highlighted the impact of psychological constructs on pain and function in chronic musculoskeletal pain conditions, yet their influence on physical activity in PFP cohorts remains unexplored. We aimed to evaluate whether pain self-efficacy and pain catastrophizing predict variations in steps per day and moderate to vigorous physical activity (MVPA) among individuals with PFP. Design: Cross-sectional observational study. Methods: Thirty-nine participants (11 males) with PFP were included. Dependent variables were steps per day and minutes of MVPA. Independent variables were pain self-efficacy and pain catastrophizing, measured by the pain self-efficacy questionnaire and the pain catastrophizing scale. Participants were given an ActiGraph wGT3X-BT for 7 days to assess physical activity. Correlations were assessed between psychological measures and physical activity, and a simple linear regression was performed on psychological variables that correlated with physical activity. Alpha was set a priori at P <.05. Results: Pain self-efficacy scores displayed a moderate association with steps per day (rho =.45, P =.004) and a weak association with MVPA (rho =.38, P =.014). Pain catastrophizing scores exhibited no significant associations with physical activity (P <.05). Regression models affirmed pain self-efficacy scores as significant predictors of both steps per day (F1,37 = 10.30, P =.002) and MVPA (F1,37 = 8.98, P =.004). Conclusions: Psychological measures continue to demonstrate value to clinicians treating PFP. Pain self-efficacy scores were moderately associated with steps per day and weakly associated with MVPA, explaining nearly a fifth of the variation in physical activity. Clinicians should prioritize the assessment of pain self-efficacy when treating individuals with PFP, potentially employing psychological interventions to improve physical activity in the PFP population. [ABSTRACT FROM AUTHOR]

Purpose: To assess associations between sedentary time (ST), physical activity (PA), and cardiovascular health in early childhood. Method: Cross-sectional study including 160 children (age 6.1 y [SD 0.5], 86 boys, 93 maternal body mass index ≥ 30 kg/m2, and 73 gestational diabetes) assessed for pulse wave velocity, echocardiography, ultra-high frequency 48–70 MHz vascular ultrasound, and accelerometery. Results: Boys had 385 (SD 53) minutes per day ST, 305 (SD 44) minutes per day light PA, and 81 (SD 22) minutes per day moderate to vigorous PA (MVPA). Girls had 415 (SD 50) minutes per day ST, 283 (SD 40) minutes per day light PA, and 66 (SD 19) minutes per day MVPA. In adjusted analyses, MVPA was inversely associated with resting heart rate (β = −6.6; 95% confidence interval, −12.5 to −0.7) and positively associated with left ventricular mass (β = 6.8; 1.4–12.3), radial intima-media thickness (β = 11.4; 5.4–17.5), brachial intima-media thickness (β = 8.0; 2.0–14.0), and femoral intima-media thickness (β = 1.3; 0.2–2.3). MVPA was inversely associated with body fat percentage (β = −3.4; −6.6 to −0.2), diastolic blood pressure (β = −0.05; −0.8 to −0.1), and femoral (β = −18.1; −32.4 to −0.8) and radial (β = −13.4; −24.0 to −2.9) circumferential wall stress in boys only. ST and pulse wave velocity showed no significant associations. Conclusions: In young at-risk children, MVPA is associated with cardiovascular remodeling, partly in a sex-dependant way, likely representing physiological adaptation, but ST shows no association with cardiovascular health in early childhood. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this review was to evaluate the effects of physical activity on children's free recall, cued recall, and recognition episodic memory and to explore potential moderating factors. Methods: The following databases were searched: PubMed, ERIC, APA Psych Info, CINHAL, SPORTDiscus, and Google Scholar. Studies were included if: (1) participants were aged 4–18 years, (2) participants were typically developed, (3) participants were randomized to groups, (4) interventions employed gross movements, (5) sedentary group was used for control, (6) memory tests were quantitative, and (7) employed acute or chronic intervention. Results: 14 studies met inclusion criteria resulting in the analysis of data from 7 free recall, 7 cued recall, and 8 recognition memory tests. Physical activity was found to have a positive influence on tests free (g = 0.56), cued recall (g = 0.67), and no influence on tests of recognition (g = 0.06). While some moderator analyses were significant, the authors do not consider these results to be meaningful in application. Conclusions: The effects of acute and chronic physical activity enhance specific aspects of long-term episodic memory. These findings suggest physical activity interventions developed for children may be expected to benefit some, but not all, types of memory processing. [ABSTRACT FROM AUTHOR]

Purpose: To quantify the change in session rating of perceived exertion training impulse (RPE-TRIMP) that may occur in response to increased running distance at 3 running velocity ranges in elite sprinters. Methods: We monitored training load in elite sprinters (women: n = 7; men: n = 11) using wearable Global Positioning System technology and RPE-TRIMP for a total of 681 individual training sessions during a 22-week competition-preparation period. Internal training load was operationalized by RPE-TRIMP, and external training load was operationalized by distance covered in 3 velocity ranges. A linear mixed-effects model with athlete as a random effect was fit to RPE-TRIMP with total distance covered at ≤69.99% (low-velocity running [LVR]), 70% to 84.99% (high-velocity running [HVR]), and 85% to 100% (very-high-velocity running [VHVR]) of individual maximum velocity. Results: Increased running distance in all 3 velocity ranges (LVR, HVR, and VHVR) resulted in a significant (P <.001) increase in RPE-TRIMP. Coefficients (95% CIs) were.10 (.08–.11) for LVR,.23 (.18–.28) for HVR, and.44 (.35–.53) for VHVR. A 50-m increase in running distance covered in the LVR, HVR, and VHVR velocity ranges was associated with increases in RPE-TRIMP of 5, 11.5, and 22 arbitrary units, respectively. Conclusions: Internal training load, calculated as RPE-TRIMP, increased with increases in total distance covered in the LVR, HVR, and VHVR velocity ranges (P <.001). RPE-TRIMP can be a practical solution for monitoring global training-session load in elite sprinters. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the influence of shorter, more frequent rest breaks with per-cooling as an alternative heat-acclimation session on physiological, perceptual, and self-paced maximal cycling performance, compared with continuous heat exposure. Methods: Thirteen participants completed 1 continuous and 3 intermittent-heat-exposure (IHE) maximal self-paced cycling protocols in a random order in heat (36 °C, 80% relative humidity): 1 × 60-minute exercise (CON), 3 × 20-minute exercise with 7.5-minute rest between sets (IHE-20), 4 × 15-minute exercise with 5-minute rest between sets (IHE-15), and 6 × 10-minute exercise with 3-minute rest between sets (IHE-10). Mixed-method per-cooling (crushed-ice ingestion and cooling vest) was applied during rest periods of all IHE protocols. Results: Total distance completed was greater in IHE-10, IHE-15, and IHE-20 than in CON (+11%, +9%, and +8%, respectively), with no difference observed between IHE protocols. Total time spent above 38.5 °C core temperature was longer in CON compared with IHE-15 and IHE-20 (+62% and +78%, respectively) but similar to IHE-10 (+5%). Furthermore, a longer time above 38.5 °C core temperature occurred in IHE-10 versus IHE-15 and IHE-20 (+54% and +69%, respectively). Sweat loss did not differ between conditions. Conclusion: IHE with per-cooling may be a viable alternative heat-acclimation protocol in situations where training quality takes precedence over thermal stimulus or when both factors hold equal priority. [ABSTRACT FROM AUTHOR]

Purpose: To develop and evaluate a theory on the frequent observation that cyclists prefer cadences (RPMs) higher than those considered most economical at submaximal exercise intensities via modeling and simulation of its mathematical description. Methods: The theory combines the parabolic power-to-velocity (v) relationship, where v is defined by crank length, RPM-dependent ankle velocity, and gear ratio, RPM effects on the maximal lactate steady state (MLSS), and lactate-dependent carbohydrate oxidation (CHO). It was tested against recent experimental results of 12 healthy male recreational cyclists determining the v-dependent peak oxygen uptake (VO2PEAKv), MLSS (MLSSv), corresponding power output (PMLSSv), oxygen uptake at PMLSSv (VO2MLSSv), and CHOMLSSv-management at 100 versus 50 per minute, respectively. Maximum RPM (RPMMAX) attained at minimized pedal torque was measured. RPM-specific maximum sprint power output (PMAXv) was estimated at RPMs of 100 and 50, respectively. Results: Modeling identified that MLSSv and PMLSSv related to PMAXv (IPMLSSv) promote CHO and that VO2MLSSv related to VO2PEAKv inhibits CHO. It shows that cycling at higher RPM reduces IPMLSSv. It suggests that high cycling RPMs minimize differences in the reliance on CHO at MLSSv between athletes with high versus low RPMMAX. Conclusions: The present theory-guided modeling approach is exclusively based on data routinely measured in high-performance testing. It implies a higher performance reserve above IPMLSSv at higher RPM. Cyclists may prefer high cycling RPMs because they appear to minimize differences in the reliance on CHO at MLSSv between athletes with high versus low RPMMAX. [ABSTRACT FROM AUTHOR]

Purpose: To (1) examine within-individual player dose–response associations between selected training-load measures and changes in aerobic fitness level via submaximal exercise heart rate (HRex%) and (2) measure the relationships between these dose–response associations with basal HRex% (to study the influence of fitness level on dose–response relationship). Methods: During an in-season phase, selected training-load measures including total minutes, total distance, mechanical work (the sum number of accelerations and decelerations > 3 m2), high metabolic load distance, and Edwards' training impulse were collected via Global Positioning System and heart-rate sensors for analyzing accumulated load. A submaximal warm-up test was used repeatedly before and after 9 phases to elicit HRex% and track fitness changes at an individual level. Results: Negative to positive extensive ranges of within-individual associations were found among players for different metrics (r = −.84 to.89). The relationship between pooled HRex% (basal fitness) and dose–response correlations showed inverse very large (r = −.71) and large (r = −.65) values for accumulated weekly minutes and distance. However, moderate values were found for all other measures (r = −.35 to −.42). Conclusions: Individual players show extensive different ranges of dose–response associations with training measures. The dose–response association is influenced by players' fitness level, and players with lower fitness levels show stronger inverse relationships with accumulated minutes and total distance. [ABSTRACT FROM AUTHOR]

No studies have reported ground reaction force (GRF) profiles of the repeated depth jump (DJ) protocols commonly used to study exercise-induced muscle damage. Furthermore, while compression garments (CG) may accelerate recovery from exercise-induced muscle damage, any effects on the repeated bout effect are unknown. Therefore, we investigated the GRF profiles of 2 repeated bouts of damage-inducing DJs and the effects of wearing CG for recovery. Nonresistance-trained males randomly received CG (n = 9) or placebo (n = 8) for 72 hours recovery, following 20 × 20 m sprints and 10 × 10 DJs from 0.6 m. Exercise was repeated after 14 days. Using a 3-way (set × bout × group) design, changes in GRF were assessed with analysis of variance and statistical parametric mapping. Jump height, reactive strength, peak, and mean propulsive forces declined between sets (P <.001). Vertical stiffness, contact time, force at zero velocity, and propulsive duration increased (P <.05). According to statistical parametric mapping, braking (17%–25% of the movement) and propulsive forces (58%–81%) declined (P <.05). During the repeated bout, peak propulsive force and duration increased (P <.05), while mean propulsive force (P <.05) and GRF from 59% to 73% declined (P <.001). A repeated bout of DJs differed in propulsive GRF, without changes to the eccentric phase, or effects from CG. [ABSTRACT FROM AUTHOR]

Physical function is regarded as the cornerstone of healthy aging, and exercise is an important determinant of healthy aging. This study examined the feasibility and physiological (heart rate, blood pressure, blood lactate, and rate of perceived exertion) and psychological (enjoyment) response resulting from an acute progressive sled-push (SLP) exercise session using the novel XPO Sled Trainer in older adults and compared that with walking (WKC) condition. The exercise session comprised six exercise bouts at 75%, 85%, 100% (2×), and 125% (2×) of normal velocity with a 2-min rest between bouts. Thirty-six older adults were randomly allocated into either the SLP or WKC conditions. No adverse events were observed during the exercise session, and all participants completed the exercise protocol as prescribed. One-third of the participants in the SLP group reported minimal body discomfort. Significantly higher responses were observed for all physiological variables as the intensity of the exercise increased in the SLP group compared with the WKC group (p <.001). The SLP group presented a decline in enjoyment as the intensity of the exercise increased (during), but similar enjoyment level than the WKC group for the overall exercise session (p =.711). Our findings support the viability and safety of SLP exercise using the XPO Sled Trainer in older adults. Such exercise demonstrated an intensity-driven modality that may have potential to elucidate positive adaptations in the cardiovascular system of older adults with acceptable levels of enjoyment. [ABSTRACT FROM AUTHOR]

Despite the well-known benefits of physical activity, less than half of adults aged 55–75 years participate in sufficient physical activity. Short bouts of vigorous intermittent lifestyle physical activity (VILPA) accumulated throughout the day can contribute toward the recommended volume of physical activity. A rich characterization of the barriers and facilitators to participation in VILPA is needed to develop targeted interventions. This scoping review aimed to identify barriers and facilitators to participation in different components of VILPA in adults aged 55–75 years, and to map barriers and facilitators to the Theoretical Domains Framework. Within the 18 eligible studies, the most prevalent barriers were related to a person's skills, environmental context, and social influences. Most facilitators were related to a person's goals, social influences, and environmental context. Interventions to promote VILPA should test the effectiveness of behavioral change measures related to the unique barriers and facilitators in this age group. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was 2-fold: (1) to examine the relationships between psychophysiological responses and locomotor demands with variations in technical performance during 2v2 and 4v4 conditioned games and (2) to compare psychophysiological and locomotor responses among players exhibiting higher and lower technical performance levels during the conditioned games. Methods: Twenty-four male youth soccer players (16.3 ± 0.8 y old) participating at the trained/developmental level underwent monitoring for psychophysiological responses (including heart rate, rating of perceived exertion, and visual analog scale), locomotor demands (such as distance covered), and technical performance variables (including successful and unsuccessful passes and shots, as well as lost balls) across 2v2 and 4v4 formats. These formats were applied 4 times within a single session and were replicated twice over 2 weeks. Results: Large correlations between the number of lost balls per minute and mean heart rate were found in both the 2v2 and 4v4 games (r =.586 and r =.665, respectively). Successful shots were inversely and largely correlated with mean heart rate (r = −.518) in 4v4 games. The number of interceptions per minute was inversely and significantly correlated with the visual analog scale in 2v2 and 4v4 games (r = −.455 and r = −.710, respectively). The frequency of lost balls was significantly higher among players who attained a higher mean heart rate (2v2: +42.9%, P =.031, d = −0.965; 4v4: +57.1%, P <.001, d = −2.072). Conclusions: Coaches should be aware that highly psychophysiologically demanding scenarios may significantly impair technical performance. Therefore, prioritizing technical performance by deliberately adjusting the intensity should be considered. [ABSTRACT FROM AUTHOR]

Background: Durability (ie, the ability to attenuate the decline in performance after accumulated work) has been identified as a performance determinant in elite cyclists. The aim of the present study was to compare durability in elite cyclists of various performance levels, particularly after high-intensity work, referred to as "high-intensity durability." Methods: Forty-nine (N = 49) male road cyclists were categorized as either under 23 years of age (U23) (N = 11), Pro Team (N = 13), or World Tour (N = 24). The participants' critical power (CP) was assessed during the preseason. Thereafter, the participants' maximum mean power (MMP) values were determined for efforts of different durations (from 5 s to 30 min) after different levels of accumulated work above CP (from 0 to 7.5 kJ·kg−1). Results: U23 cyclists showed a significant reduction of all relative MMP values for durations ≥1 minute after ≥5 kJ·kg−1 above CP compared with the "fresh" state (0 kJ·kg−1), whereas in Pro Team and World Tour cyclists, a significant reduction was not observed until 7.5 kJ·kg−1 above CP. In the "fresh" state, both Pro Team and particularly World Tour cyclists attained higher MMP values for efforts ≥10 minutes than U23 riders. However, more differences emerged with greater previous work levels, and indeed after 7.5 kJ·kg−1 above CP World Tour cyclists attained higher MMP values than both U23 and Pro Team cyclists for most efforts (≥30 s). Conclusion: Pro Team and particularly World Tour cyclists tolerate greater levels of accumulated work at high intensity, which might support the importance of high-intensity durability for performance. [ABSTRACT FROM AUTHOR]

There has been an increase in the use of commercially available multi-ingredient preworkout supplements (MIPS); however, there are inconsistencies regarding the efficacy of MIPS in resistance-trained women. Purpose: To determine the effect of varying doses of MIPS compared with caffeine only (C) and a placebo (PL) on resistance-training performance in trained women. Methods: Ten women (21.5 [2.3] y) completed 1-repetition-maximum tests at baseline for leg press and bench press. A within-group, double-blind, and randomized design was used to assign supplement drinks (ie, PL, C, MIPS half scoop [MIPS-H], and MIPS full scoop [MIPS-F]). Repetitions to failure were assessed at 75% and 80% to 85% of 1-repetition maximum for bench and leg press, respectively. Total performance volume was calculated as load × sets × repetitions for each session. Data were analyzed using a 1-way repeated-measures analysis of variance and reported as means and SDs. Results: There were no differences in repetitions to failure for bench press (PL: 14.4 [3.2] repetitions, C: 14.4 [2.9] repetitions, MIPS-H: 14.2 [2.6] repetitions, MIPS-F: 15.1 [3.1] repetitions; P =.54) or leg press (PL: 13.9 [7.8] repetitions, C: 10.8 [5.9] repetitions, MIPS-H: 13.1 [7.1] repetitions, MIPS-F: 12.4 [10.7] repetitions; P =.44). Furthermore, there were no differences in total performance volume across supplements for bench press (PL: 911.2 [212.8] kg, C: 910.7 [205.5] kg, MIPS-H: 913.6 [249.3] kg, MIPS-F: 951.6 [289.6] kg; P =.39) or leg press (PL: 4318.4 [1633.6] kg, C: 3730.0 [1032.5] kg, MIPS-H: 4223.0 [1630.0] kg, MIPS-F: 4085.5 [2098.3] kg; P =.34). Conclusions: Overall, our findings suggest that caffeine and MIPS do not provide ergogenic benefits for resistance-trained women in delaying muscular failure. [ABSTRACT FROM AUTHOR]

Purpose: To determine between-limbs differences in isometric rate of force development (RFD) measured during open- (OKC) and closed-kinetic-chain (CKC) strength testing and establish which method had the strongest relationship to single-leg vertical-jump performance and knee mechanics after anterior cruciate ligament (ACL) reconstruction. Methods: Subjects (n = 19) 1 to 5 years from ACL reconstruction performed isometric knee extensions (OKC), unilateral isometric midthigh pulls (CKC), and single-leg vertical jumps on the ACL-involved and -noninvolved limbs. Between-limbs differences were assessed using paired t tests, and the relationship between RFD, jump performance, and knee mechanics was assessed using correlation coefficients (r; P ≤.05). Results: There were significant between-limbs differences in OKC RFD (P =.008, d = −0.69) but not CKC RFD. OKC RFD in the ACL-involved limb had a strong association with jump height (r =.64, P =.003), knee-joint power (r =.72, P <.001), and peak knee-flexion angle (r =.72, P =.001). CKC RFD in the ACL-involved limb had a strong association with jump height (r =.65, P =.004) and knee-joint power (r =.67, P =.002) but not peak knee-flexion angle (r =.40, P =.09). Conclusions: While both OKC and CKC RFD were strongly related to jump performance and knee-joint power, OKC RFD was able to detect between-limbs RFD asymmetries and was strongly related to knee-joint kinematics. These findings indicate that isometric knee extension may be optimal for assessing RFD after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Purpose: The study had 3 purposes: (1) to develop an index using machine-learning techniques to predict the fitness status of soccer players, (2) to explore the index's validity and its relationship with a submaximal run test (SMFT), and (3) to analyze the impact of weekly training load on the index and SMFT outcomes. Methods: The study involved 50 players from an Italian professional soccer club. External and internal loads were collected during training sessions. Various machine-learning algorithms were assessed for their ability to predict heart-rate responses during the training drills based on external load data. The fitness index, calculated as the difference between actual and predicted heart rates, was correlated with SMFT outcomes. Results: Random forest regression (mean absolute error = 3.8 [0.05]) outperformed the other machine-learning algorithms (extreme gradient boosting and linear regression). Average speed, minutes from the start of the training session, and the work:rest ratio were identified as the most important features. The fitness index displayed a very large correlation (r =.70) with SMFT outcomes, with the highest result observed during possession games and physical conditioning exercises. The study revealed that heart-rate responses from SMFT and the fitness index could diverge throughout the season, suggesting different aspects of fitness. Conclusions: This study introduces an "invisible monitoring" approach to assess soccer player fitness in the training environment. The developed fitness index, in conjunction with traditional fitness tests, provides a comprehensive understanding of player readiness. This research paves the way for practical applications in soccer, enabling personalized training adjustments and injury prevention. [ABSTRACT FROM AUTHOR]

Purpose: Precooling (PreC) may only benefit performance when thermal strain experienced by an individual is sufficiently high. We explored the effect of mixed-method PreC on 20-km cycling time-trial (CTT) performance under 3 different apparent temperatures (AT). Methods: On separate days, 12 trained or highly trained male cyclists/triathletes completed six 20-km CTTs in 3 different ATs: hot-dry (35 °C AT), moderately hot-humid (40 °C AT), and hot-humid (46 °C AT). All trials were preceded by 30 minutes of mixed-method PreC or no PreC (control [CON]). Results: Faster 2.5-km-split completion times occurred in PreC compared with CON in 46 °C AT (P =.02), but not in 40 °C AT (P =.62) or 35 °C AT (P =.57). PreC did not affect rectal and body temperature during the 20-km CTT. Skin temperature was lower throughout the CTT in PreC compared with CON in 46 °C AT (P =.01), but not in 40 °C AT (P = 1.00) and 35 °C AT (P = 1.00). Heart rate had a greater rate of increase during the CTT for PreC compared with CON in 46 °C AT (P =.01), but not in 40 °C AT (P =.57) and 35 °C AT (P = 1.00). Ratings of perceived exertion (P <.001) and thermal comfort (P =.04) were lower for PreC compared with CON in 46 °C AT only, while thermal sensation was not different between PreC and CON. Conclusion: Mixed-method PreC should be applied prior to 20-km CTTs conducted in hot-humid conditions (≥46 °C AT). Alternatively, mixed-method PreC may be a priority in moderately hot-humid (∼40 °C AT) conditions but should not be in hot-dry (∼35 °C AT) conditions for 20-km CTT. [ABSTRACT FROM AUTHOR]

Purpose: Monitoring performance athletes' training responses can be efficiently completed at competitive events. This study aimed to explore the changes in swimming, countermovement-jump (CMJ), and pull-up (PU) performance following training across a competitive phase, as well as immediately before and after each race. Methods: Fourteen well-trained male sprint/middle-distance swimmers (height 179 [7] cm, mass 70 [8] kg, age 18 [2] y), from 3 regional training groups, completed CMJ and PU tests before and after the national competitions in October and May, when race performance was also assessed. Results: Swimming race performance was significantly improved from before the national competitions in October to after the national competitions in May (1.8% [3.2%], P =.044, d = 0.60, moderate effect). Although there were no significant changes in PU velocity, CMJ performance significantly improved from before the national competitions in October to after the national competitions in May (mean difference 2.29 cm, P =.004, d = 3.52) and showed before-to-after race decreases (mean difference −1.64 cm, P =.04, d = 2.28). Conclusion: Swimming performance and CMJ performance improved as the season progressed, although these improvements were not directly correlated. PU performance did not appear to be sensitive to training or race-induced fatigue, in contrast to CMJ, in this group of male swimmers. [ABSTRACT FROM AUTHOR]

Introduction: The acute and isolated ingestion of sodium bicarbonate (NaHCO3) and caffeine (CAF) improves performance and delays fatigue in high-intensity tasks. However, it remains to be elucidated if the coingestion of both dietary supplements stimulates a summative ergogenic effect. This study aimed to examine the effect of the acute coingestion of NaHCO3 and CAF on repeated-sprint performance. Methods: Twenty-five trained participants (age: 23.3 [4.0] y; sex [female/male]: 12/13; body mass: 69.6 [12.5] kg) participated in a randomized, double-blind, placebo (PLA) -controlled, crossover study. Participants were assigned to 4 conditions: (1) NaHCO3 + CAF, (2) NaHCO3, (3) CAF, or (4) PLA. Thus, they ingested 0.3 g/kg of NaHCO3, 3 mg/kg of CAF, or PLA. Then, participants performed 4 Wingate tests (Wt), consisting of a 30-second all-out sprint against an individualized resisted load, interspersed by a 1.5-minute rest period between sprints. Results: Peak (Wpeak) and mean (Wmean) power output revealed a supplement and sprint interaction effect (P =.009 and P =.049, respectively). Compared with PLA, NaHCO3 + CAF and NaHCO3 increased Wpeak performance in Wt 3 (3%, P =.021) and Wt 4 (4.5%, P =.047), while NaHCO3 supplementation increased mean power performance in Wt 3 (4.2%, P =.001). In Wt 1, CAF increased Wpeak (3.2%, P =.054) and reduced time to Wpeak (−8.5%; P =.008). Plasma lactate showed a supplement plus sprint interaction (P <.001) when NaHCO3 was compared with CAF (13%, P =.031) and PLA (23%, P =.021). Conclusion: To summarize, although the isolated ingestion of CAF and NaHCO3 improved repeated-sprint performance, the coingestion of both supplements did not stimulate a synergic ergogenic effect. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to describe the day-by-day training and racing characteristics in preparation for the Giro d'Italia of 1 world-class road cyclist who achieved a place on the podium in the final general classification of the Giro d'Italia. Methods: Day-by-day power meter training and racing data of 1 study subject (road cyclist; age 25 y; relative maximum oxygen consumption 81 mL·min−1·kg−1; relative 20-min record power output 6.6 W·kg−1) covering the 152 days leading up to the podium in the Giro d'Italia final general classification were retrospectively analyzed. Daily load, daily volume, and intensity distribution were considered. Results: During training a pattern alternating "hard days" versus "easy days" was observed, as significant amounts of medium or high intensity, or load, were not performed for more than 2 consecutive days This pattern was achieved combining high volume (>4 h) with a significant amount of medium and high intensity within the same training sessions. During training, when training load and intensity increased, the density of "easy days" augmented. In 1-week stage races and the Giro d'Italia, 3 to 8 consecutive days with significant amounts of medium and high intensity were performed. A high number of training sessions with small amounts of medium- and high-intensity volume was observed: 38 days accumulating 3 to 10 minutes at medium intensity and 29 days spending 1 to 9 minutes at high intensity. Conclusion: These data provide novel insights about the day-by-day periodization strategies leading to a top 3 in the Giro d'Italia general classification. [ABSTRACT FROM AUTHOR]

In articles on the methodology of studies investigating affective and enjoyment responses to high-intensity interval training, we noted that, occasionally, exercise conditions described as involving "high" intensity exhibited heart rates that were only as high as, or even lower than, heart rates recorded during comparator conditions described as being of "moderate" intensity. Drs. Vollaard, Metcalfe, Kinghorn, Jung, and Little suggest instead that exercise intensity in high-intensity interval-training studies can be defined in terms of percentages of peak workload. Although we maintain that defining exercise intensity in terms of percentages of maximal heart rate is a suboptimal way to quantify the degree of homeostatic perturbations in response to exercise, we are unconvinced that definitions of intensity relying solely on workload are appropriate for studies investigating affective and enjoyment responses to exercise. The reason is that affect is theorized to have evolved to relay information about homeostatic perturbations to consciousness. [ABSTRACT FROM AUTHOR]

Older adults face numerous unfavorable functional changes caused by aging, but many exhibit resilience, which helps them cope with challenges. Physical activity is positively associated with resilience. Therefore, this systematic literature review aimed to uncover the relationships between physical activity and resilience in older adults. We have analyzed three freely and openly available databases: (a) PubMed/Medline, (b) ScienceDirect, and (c) Google Scholar, which yielded 20 eligible articles based on the inclusion and exclusion criteria. Most studies (14) were cross-sectional, three were longitudinal, and three others used mindfulness-based or endurance-enhancing physical activity interventions. Their results revealed increased resilience even after short-duration and low-frequency interventions. Cross-sectional research results also support the positive relationship between physical activity and resilience in older adults, suggesting that the relationship might depend on exercise volume. Still, further research is needed to design interventions, understand the mechanism(s) involved in altering resilience, and maximize physical activity's benefits in aging people. [ABSTRACT FROM AUTHOR]

Purpose: The aims of this study were to examine the variability of selected external load metrics within 15-minute intervals during soccer match play and examine their relationship with players' high-intensity intermittent fitness. Methods: A total of 18 male soccer players were monitored for their external load metrics during 26 matches, which included total distance, high-metabolic-load distance, and mechanical work (defined as the sum of accelerations and decelerations >3 m2). Additionally, players completed the 30-15 Intermittent Fitness Test. Results: Total distance had lower coefficients of variation than high-metabolic-load distance and mechanical work (effect size [ES]: 5.2 to 6.4; very large). Within-player Δ-15min showed moderate to large decreases (ES: −0.7 to −1.6) and increases (ES: 0.9 to 1.8) in absolute and coefficient-of-variation values, respectively. Large relationships (r =.55 to.61) were observed between the Intermittent Fitness Test and 15-minmean and 15-minbest in all selected external load metrics. However, small to moderate (0.27 to 0.41) associations were observed between the Intermittent Fitness Test and Δ-15min in selected external load metrics. Conclusions: These findings suggest that players with relatively lower intermittent running capacity might show lower variability during matches, as evidenced by smaller reductions in high-intensity actions during the final 15 minutes. We attribute these observations to players' possessing better pacing strategies. [ABSTRACT FROM AUTHOR]

Purpose: Ultramarathon running has gained popularity over several decades. Although there has been considerable research on training for other running events, from the 100-m to the marathon at 26.2 miles (42.2 km), there is little evidence on best practices for ultramarathons, where distances potentially exceed 100 miles (160.9 km). Methods: In this case study, we examine the training regimen of an elite ultramarathon runner who broke 8 world records in 2021 and 2022, including the 24-hour run in which he ran 319.6 km in September 2022. Training data from December 28, 2020, to September 17, 2022, were collected from the Strava application database (recorded on Coros watch) and analyzed using Microsoft Excel and Tableau. Results: Our subject completed 5 training blocks, with volume per training block averaging 172.1 to 263 km/wk. Peak running volume per training block occurred on average 3.2 weeks out from races and reached a maximum of 378 km/wk. Recovery was emphasized the week following a race, with less running (19 km/wk) and more cross-training. Interval-type workouts (1- to 10-km repeats) were completed throughout training blocks. The average pace during the 24-hour world-record run was 4 minutes and 30 seconds per kilometer (4:30/km), closely matching the overall average training pace. Conclusions: These findings suggest that training for ultramarathon races should include high-volume running at varied paces and intensity with cross-training to avoid injuries. We hope that this evidence helps athletes understand how to prepare for these ultraendurance events. [ABSTRACT FROM AUTHOR]

Context: Wheelchair Power Soccer (WPS) is the only team sport that allows the participation of people with severe physical disabilities who require the daily use of motorized wheelchairs. These individuals may live with chronic pain due to the characteristics of the disabilities and treatments, interfering with their health and limiting their participation in sports. Objectives: To investigate the prevalence of musculoskeletal pain and its relationship with mood in WPS players and to analyze the incidence of traumatic injuries during a championship. Methods: A prospective, longitudinal study was carried out on 30 WPS athletes (93.33% male) with a mean (SD) (range) age of 22.37 (9.79) (47) years. Data collection was performed during a South American WPS Championship lasting 3 days, with: investigation of the presence of musculoskeletal pain and mood through a questionnaire; investigation of the occurrence of traumatic injuries through match observation; and confirmation of the occurrence of traumatic injuries through access to medical department records. Results: About 30% (n = 9/30) of the sample presented some pain on the day of evaluation, with an intensity of 5.67 (3.35) (10) points on the visual analog scale. The most common regions of pain were the lower back (13.3%, n = 4/30), thoracic (10%; n = 3/30), and cervical (10%; n = 3/30) areas of the spine. A total of 46.7% (n = 14/30) reported pain in the month before data collection but of less intensity (2.56 [4] [10] points), the most common regions being the lower limbs (20%; n = 6/30) and cervical spine (20%; n = 6/30). Among the between-group comparisons (ie, participants with pain vs without pain), no relationship was observed between mood state and pain. No traumatic injuries were identified during the competition. Conclusion: The presence of musculoskeletal pain was common in WPS players, but it was not related to mood. As no traumatic injuries were observed during the championship, this modality seems to be safe for people with physical disabilities in general. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of unilateral flywheel training (FT), using a rotational conical pulley, including multidirectional movements with either preplanned or random unanticipated/unexpected executions on functional performance in football players. Methods: A total of 32 young male football players were randomly assigned to an FT program including preplanned unilateral multidirectional movements (PTG, n = 11), an FT executing the same unilateral movements through random (ie, right or left leg) unanticipated (ie, verbal or visual cue) or unexpected (ie, moment where the cue was provided) situations (UTG, n = 11), or a control group (n = 10) that followed their football training routine. FT consisted of 1 set × 5–12 repetitions of 4 exercises performed once a week for 10 weeks. Intermittent endurance performance, repeated unilateral and bilateral jumping ability, change-of-direction (COD) ability, linear sprint velocity, preplanned repeated-sprint ability (RSA), and uncertainty RSA (RSA-RANDOM) were assessed preintervention and postintervention. Results: Significant improvements were found in RSA-RANDOM performance (P <.05, effect size [ES] range: UTG [1.83–2.16], PTG [0.69–0.73]) and COD (P <.05, ES: UTG = 1.34, PTG = 0.98]) in both training groups. Furthermore, significant improvements were also found in intermittent endurance performance (P =.016, ES = 0.37) and sprinting (P =.006, ES = 0.45) in UTG. No changes in any variable were found in the control group. No significant between-groups differences (P >.05) were reported between UTG and PTG, while differences were observed to the control group in unilateral jumping ability, COD, and RSA-RANDOM for UTG, and in RSA-RANDOM for PTG. Conclusions: A 10-week unilateral FT improved RSA-RANDOM and COD ability in youth football players, so both preplanned and unexpected situations should be included on strength training. [ABSTRACT FROM AUTHOR]

Adaptations to resistance training and subsequent performance can be undermined by inadequate interset recovery. Methods typically used to monitor recovery were developed for longitudinal use, making them time-inefficient within singular exercise bouts. If valid, perceptual recovery status (PRS) may be used as an efficient and inexpensive assessment tool to monitor individual recovery. Purpose: The aim of this study was to assess the validity of PRS on monitoring recovery during a high-intensity back-squat session. Methods: Ten healthy men participated in the 2-session study (separated by at least 48 h). Session 1 included anthropometrics, PRS familiarization, and a 1-repetition-maximum back squat. Session 2 included a high-intensity protocol (5 sets of 5 repetitions; 5-min interset recovery; 85% of 1-repetition maximum). PRS was obtained before the first set and during the last 30 seconds of each 5-minute recovery; rating of perceived exertion (RPE) was also collected. A linear position transducer collected mean barbell velocity (MBV). Repeated-measures correlations assessed the common intraindividual relationships of PRS scores to intraset MBV and RPE, respectively. Results: A very large, positive correlation appeared between PRS and MBV (r [95% CI] =.778 [.613 to.878]; P <.0001). A large, negative correlation emerged between PRS and RPE (r [95% CI] = −.549 [−.737 to −.282]; P <.001). Conclusions: Results indicate that PRS can be a means for practitioners to monitor individualized recovery. PRS tracked well with RPE, strengthening its utility in a practitioner-based setting. Findings provide insight into the practicality of PRS for recovery monitoring. It could be used alongside other measures (eg, MBV and countermovement jump) to individually program and maintain performance. [ABSTRACT FROM AUTHOR]

The purpose of this investigation was (1) to test the effect of movement restriction of the free leg during unilateral vertical jump on performance and power output comparing 2 different jump techniques: flexed (Classic technique) and straight (FC Luzern technique) free leg, and (2) to test the correlation between performance and power output obtained using these 2 techniques. Twenty elite soccer players performed squat (SJ) and countermovement (CMJ) jumps on each leg. The jump height and peak power output were compared between the 2 techniques for both legs. The jump height and peak power were significantly higher for the classic test for SJ and CMJ (P <.001) with no side effects or interactions. The angular range of motion of the free leg was higher for the Classic test than for the FC Lucerne test (P <.001), with no difference in the angular range of motion of the trunk. A moderate correlation was found between the 2 techniques on peak power (SJ: r =.626; CMJ: r =.649) and jump height (SJ: r =.742; CMJ: r =.891). Consequently, FC Lucerne technique, limiting the contribution of the free leg, is more appropriate to assess lower limb strength capacities during unilateral jump test. [ABSTRACT FROM AUTHOR]

Purpose: School recess provides a valuable opportunity for children's daily moderate- to vigorous-intensity physical activity (MVPA). This study aimed to quantify MVPA during school recess in a representative sample of Scottish children and examine whether recess MVPA varied by gender, socioeconomic status, season, urban/rural residency, and recess length. Method: Five-day accelerometry MVPA data were analyzed from 773 children (53.9% girls, 46.1% boys, 10- to 11-y-olds) from 471 schools. Binary logistic regression explored associations between meeting/not meeting the recommendation to spend 40% of recess time in MVPA and the aforementioned risk factors. Descriptive recess data were also analyzed. Results: Participants spent an average of 3.2 minutes (SD 2.1) in MVPA during recess. Girls engaged in 2.5 minutes (SD 1.7) of MVPA compared with 4.0 minutes (SD 2.2) for boys. Only 6% of children met the recess MVPA recommendation. The odds of girls (odds ratio 0.09; 95% confidence interval, 0.04–0.25) meeting the recommendation was lower (P <.001) compared with boys. No statistically significant differences were observed in meeting the recommendation for the other risk factors. Conclusion: Levels of MVPA during school recess are very low in Scottish children, and interventions aimed at increasing MVPA during recess are needed. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the validity of the Physical Activity Questionnaire for Older Children (PAQ-C) to assess the moderate- to vigorous-intensity physical activity (MVPA) level of children and adolescents diagnosed with HIV and propose cut-points, with accelerometer measures as the reference method. Method: Children and adolescents, aged 8–14 years (mean age = 12.21 y, SD = 2.09), diagnosed with HIV by vertical transmission, participated in the study. MVPA was investigated through the PAQ-C and triaxial accelerometer (ActiGraph GT3X+). Receiver operating characteristic curve and sensitivity and specificity values were used to identify a cut-point for PAQ-C to distinguish participants meeting MVPA guidelines. Results: Fifty-six children and adolescents participated in the study. Among those, 16 met MVPA guidelines. The PAQ-C score was significantly related to accelerometry-derived MVPA (ρ =.506, P <.001). The PAQ-C score cut-point of 2.151 (sensitivity = 0.625, specificity = 0.875) was able to discriminate between those who met MVPA guidelines and those that did not (area under the curve = 0.751, 95% confidence interval, 0.616–0.886). Conclusion: The PAQ-C was useful to investigate MVPA among children and adolescents diagnosed with HIV and to identify those who meet MVPA guidelines. [ABSTRACT FROM AUTHOR]

Purpose: A decline in youth running was observed at the start of the COVID-19 pandemic. We investigated whether the resumption of organized running after social distancing restrictions changed running habits or injury frequency in adolescent runners. Methods: Adolescents (age = 16.1 [2.1] y) who participated in long-distance running activities completed an online survey in the Spring and Fall of 2020. Participants self-reported average weekly running habits and whether they sustained an injury during the Fall 2020 season. Poisson regression models and 1-way analysis of variance compared running habits while Fisher exact test compared differences in frequencies of injuries during Fall 2020 among season statuses (full, delayed, and canceled). Results: All runners, regardless of season status, increased weekly distance during Fall 2020. Only runners with a full Fall 2020 season ran more times per week and more high-intensity runs per week compared with their Spring 2020 running habits. There were no differences in running volume or running-related injury frequency among Fall 2020 season statuses. Conclusions: There were no significant differences in running-related injury (RRI) frequency among runners, regardless of season status, following the resumption of cross-country. Health care providers may need to prepare for runners to increase running volume and intensity following the resumption of organized team activities. [ABSTRACT FROM AUTHOR]

Purpose: To investigate performance-determining variables of an on-snow sprint cross-country skiing competition and the evolvement in their relationship with performance as the competition progresses from the individual time trial (TT) to the final. Methods: Sixteen national-level male junior skiers (mean [SD] age, 18.6 [0.8] y; peak oxygen uptake [VO2peak], 67.6 [5.5] mL·min−1·kg−1) performed a simulated sprint competition (1.3 km) in the skating style, comprising a TT followed by 3 finals (quarterfinals, semifinals, and final) completed by all skiers. In addition, submaximal and incremental roller-ski treadmill tests, on-snow maximal speed tests, and strength/power tests were performed. Results: VO2peak and peak treadmill speed during incremental testing and relative heart rate, rating of perceived exertion, blood lactate concentrations, and gross efficiency during submaximal testing were all significantly correlated with performance in the TT and subsequent finals (mean [range] r values:.67 [.53–.86], all P <.05). Relative VO2peak and submaximal relative heart rate and blood lactate concentration were more strongly correlated with performance in the semifinals and final compared with the TT (r values:.74 [.60–.83] vs 0.55 [.51–.60], all P <.05). Maximal speed in uphill and flat terrain was significantly correlated with performance in the TT and subsequent finals (r values:.63 [.38–.70], all P <.05), while strength/power tests did not correlate significantly with sprint performance. Conclusions: VO2peak and high-speed abilities were the most important determinants of sprint cross-country skiing performance, with an increased importance of VO2peak as the competition format progressed toward the final. [ABSTRACT FROM AUTHOR]

Purpose: There are important methodological considerations for translating wearable-based gait-monitoring data to field settings. This study investigated different devices' sampling rates, signal lengths, and testing frequencies for athlete monitoring using dynamical systems variables. Methods: Secondary analysis of previous wearables data (N = 10 runners) from a 5-week intensive training intervention investigated impacts of sampling rate (100–2000 Hz) and signal length (100–300 strides) on detection of gait changes caused by intensive training. Primary analysis of data from 13 separate runners during 1 week of field-based testing determined day-to-day stability of outcomes using single-session data and mean data from 2 sessions. Stride-interval long-range correlation coefficient α from detrended fluctuation analysis was the gait outcome variable. Results: Stride-interval α reduced at 100- and 200- versus 300- to 2000-Hz sampling rates (mean difference: −.02 to −.08; P ≤.045) and at 100- compared to 200- to 300-stride signal lengths (mean difference: −.05 to −.07; P <.010). Effects of intensive training were detected at 100, 200, and 400 to 2000 Hz (P ≤.043) but not 300 Hz (P =.069). Within-athlete α variability was lower using 2-session mean versus single-session data (smallest detectable change:.13 and.22, respectively). Conclusions: Detecting altered gait following intensive training was possible using 200 to 300 strides and a 100-Hz sampling rate, although 100 and 200 Hz underestimated α compared to higher rates. Using 2-session mean data lowers smallest detectable change values by nearly half compared to single-session data. Coaches, runners, and researchers can use these findings to integrate wearable-device gait monitoring into practice using dynamic systems variables. [ABSTRACT FROM AUTHOR]

Purpose: As a multidisciplined combat sport, relationships between external and internal training loads and intensities of mixed martial arts (MMA) have not been described. The aim of this study was to determine the external loads and intensities of MMA training categories and their relationship to internal loads and intensities. Methods: Twenty MMA athletes (age = 23.3 [5.3] y, mass = 72.1 [7.2] kg, stature = 171.5 [8.4] cm) were observed for 2 consecutive weeks. Internal load and intensity (session rating of perceived exertion [sRPE]) were calculated using the Foster RPE for the session overall (sRPE-training load [TL]) and segmented RPE (segRPE-TL) for each training category: warm-up, striking drills, wrestling drills, Brazilian jiujitsu (BJJ) drills, striking sparring, wrestling sparring, BJJ sparring, and MMA sparring. External load and intensity were measured via Catapult OptimEye S5 for the full duration of each session using accumulated Playerload (PLdACC) and PLdACC per minute (PLdACC·min−1). Differences in loads between categories and days were assessed via Bayesian analysis of variance (BF10 ≥ 3). Predictive relationships between internal and external variables were calculated using Bayesian regression. Results: Session overall sRPE-TL = 448.6 (191.1) arbitrary units (AU); PLdACC = 310.6 (112) AU. Category segRPE-TL range = 33.8 (22.6) AU (warm-up) to 122.8 (54.6) AU (BJJ drills). Category PLdACC range = 44 (36.3) AU (warm-up) to 125 (58.8) AU (MMA sparring). Neither sRPE-TL nor PLdACC changed between days. PLdACC was different between categories. Evidence for regressions was strong-decisive except for BJJ drills (BF10 = 7, moderate). R2 range =.50 to.77, except for warm-up (R2 =.17), BJJ drills (R2 =.27), BJJ sparring (R2 =.49), and session overall (R2 =.13). Conclusions: While MMA training categories may be differentiated in terms of external load, overall session external load does not change within or between weeks. Resultant regression equations may be used to appropriately plan MMA technical/tactical training loads. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effect of exercise intensity on the proportion and rate of carbohydrate oxidation and glucoregulatory hormone responses during recovery from exercise. Six physically active participants completed 1 hr of low-intensity (LI; 50% lactate threshold) or moderate-intensity (MI; 100% lactate threshold) exercise on separate days following a randomized counterbalanced design. During exercise and for 6 hr of recovery, samples of expired air were collected to determine oxygen consumption, respiratory exchange ratio, energy expenditure, and substrate oxidation rates. Blood samples were also collected to measure glucoregulatory hormones (catecholamines, GH) and metabolites (glucose, free fatty acids, lactate, pH, and bicarbonate). During exercise, respiratory exchange ratio, energy expenditure, and the proportion and rate of carbohydrate (CHO) oxidation were higher during MI compared with LI. However, during recovery from MI, respiratory exchange ratio and the proportion and rate of CHO oxidation were lower than preexercise levels and corresponding LI. During exercise and early recovery, catecholamines and growth hormone were higher in MI than LI, and there was a trend for higher levels of free fatty acids in the early recovery from MI compared with LI. In summary, CHO oxidation during exercise increases with exercise intensity but there is a preference for CHO sparing (and fat oxidation) during recovery from MI exercise compared with LI exercise. This exercise intensity-dependent shift in substrate oxidation during recovery is explained, in part, by the pattern of change of key glucoregulatory hormones including catecholamines and growth hormone and plasma fatty acid concentrations. [ABSTRACT FROM AUTHOR]