European Journal of Applied Physiology最新文献

Resistance training (RT) load and volume are considered crucial variables to appropriately prescribe and manage for eliciting the targeted acute responses (i.e., minimizing neuromuscular fatigue) and chronic adaptations (i.e., maximizing neuromuscular adaptations). In traditional RT contexts, load and volume are generally pre-prescribed; thereby, potentially yielding sub-optimal outcomes. A RT concept that individualizes programming is autoregulation: a systematic two-step feedback process involving, (1) monitoring performance and its constituents (fitness, fatigue, and readiness) across multiple time frames (short-, moderate-, and long-term); and (2) adjusting programming (i.e., load and volume) to elicit the targeted goals (i.e., responses and adaptations). A growing body of load and volume autoregulation research has accelerated recently, with several meta-analyses suggesting that autoregulation may provide a small advantage over traditional RT. Nonetheless, the existing literature has typically conceptualized these current autoregulation methods as standalone practices, which has limited their extensive utility in research and applied settings. The primary purpose of this review was three-fold. Initially, we synthesized the current methods of load and volume autoregulation, while disseminating each method's main advantages and limitations. Second, we conceptualized a theoretical Integrated Velocity Model (IVM) that integrates the current methods for a more holistic perspective of autoregulation that may potentially augment its benefits. Lastly, we illustrated how the IVM may be compared to the current methods for future directions and how it may be implemented for practical applications. We hope that this review assists to contextualize a novel autoregulation framework to help inform future investigations for researchers and practices for RT professionals.

Skeletal muscle shear elastic modulus is a non-invasive surrogate for early detection of muscle damage and soreness consequent to unaccustomed eccentric muscle work. We investigated the influence of marathon distance running on skeletal muscle shear elastic modulus. Shear modulus of the rectus femoris was measured via ultrasound shear wave elastography in 80 participants (30 female, 50 male) before and after running a World Marathon Major. Experience level, muscle soreness and run readiness were surveyed. Pre-marathon shear elastic modulus was lower in competitive vs recreational runners (13.0 ± 4.6 vs 15.6 ± 5.6 kPa; P = 0.0014), lower for fastest vs slowest finish times (11.6 ± 3.0 vs 16.9 ± 6.5 kPa; P =  < 0.0001) and associated with marathon finish time (r = - 0.40; P < 0.0003). Marathon running increased shear modulus (~ 23%), irrespective of experience, sex or course, but was blunted in runners wearing highly cushioned footwear with plates who had matched finish times (Other =  ~ 31% vs Vaporfly =  ~ 17%). Muscle soreness was strongly associated with run readiness (R² = 0.995; P = 0.0026), and marathon recovery time was longer in runners with greater increases in marathon-mediated shear modulus. Skeletal muscle elastic modulus may reflect both short- and long-term muscle adaptation as a function of marathon running, or factors occurring before or after a marathon itself, such as exercise capacity or recovery time. These data are consistent with marathon-mediated muscle damage and soreness, but equally highlight a possibility to monitor and modulate outcomes in favor of a runner.

Osteogenesis with impact-loading exercise is often assessed by the extra bone growth induced in the loaded arm of tennis players. We used PRISMA to explore % bone mineral content (BMC) and area (BA) asymmetry in players 8-30 years according to weekly training hours, age, sex, maturity, and bone segment. Proper statistics for 70 groups were extracted by two reviewers from 18 eligible studies of low risk of bias (< 35, STROBE) and good quality (> 70%). The quality of the review was high (AMSTAR, 81%). Using "random effects" we tested moderation-specific meta-comparisons and meta-regressions. The loaded bones % hypertrophy was higher in BMC (19%) than BA (10%), and, with BMC and BA merged, in boys (17%) than girls (13%), in humerus (19%) than radius-ulna (14%), and in pubertal (19%) players. Weekly training hours were more important (43%) than sex (17%), puberty (14%) and bone (15%) in BMC, and puberty (48%) was more important than weekly training hours (19%), sex (12%), and radius-ulna (5%) in BA. The loaded bones % hypertrophy correlated with weekly training hours highly (> 0.60) in all maturity groups for BMC and BA, and moderately (0.41) in early adults for BA; it also correlated with age (≥ 0.60) in children and peripubertal players, but not (0.037) with starting age. Impact loading exercise favors mineralization twice than bone expansion, while puberty favors bone expansion about three times more than mineralization. The bone gains are higher for boys than girls, and for peripubertal than older players. The bone growth implications are discussed considering limitations and future research.

Nociceptors contribute to the cardiovascular responses during a cold pressor test (CPT). While these responses are lower in females, data suggest that they perceive the CPT as more painful. Thus, we examined sex differences in associations between pain and cardiovascular responses to a CPT (Aim 1) as well as differences between females using (OC), and not using (NC), an oral contraceptive (Aim 2). 25 males (23 ± 5 years) and 25 females (21 ± 3 years; 11OC and 14NC) were studied. Cardiovascular data and pain levels (0-10 scale) were recorded at baseline then during a two-minute CPT; changes from baseline to peak response were analyzed. Systolic blood pressure (SBP, p = 0.57), mean arterial pressure (MAP, p = 0.22), heart rate (HR, p = 0.58), and pain (p = 0.71) responses did not differ between sexes; diastolic blood pressure (DBP) increased more in males (17 ± 8 vs. 13 ± 6 mmHg, p < 0.05). Pain was associated with HR in males (r = 0.42, p < 0.05) but not females (r = -0.16, p = 0.44); no other associations were observed in either sex (p = 0.48-0.92). SBP (27 ± 12 vs. 15 ± 6 mmHg), DBP (16 ± 6 vs. 9 ± 5 mmHg), MAP (20 ± 7 vs. 14 ± 5 mmHg), and HR (8 ± 5 vs. 2 ± 5 beats/min) were greater in NC than OC (p < 0.05 for all); pain was similar (p = 0.38). In NC, pain was associated with DBP (r = 0.65, p = 0.01) and MAP (r = 0.65, p = 0.01), but not HR (r = -0.43, p = 0.13), and tended to be associated with SBP (r = 0.46, p = 0.09). In OC, pain was inversely associated with SBP (r = -0.62, p < 0.05) but no other outcome (p = 0.40-0.65). We report a sexual dimorphism in the HR-pain association during a CPT and underscore the impact of oral contraceptives.

Purpose: The aim of this study was to investigate the influence of prolonged aerobic exercise on cardiac, muscular and renal inflammatory markers in a group of trained obese men.

Methods: Seventeen men (aged 40 ± 6 years; body mass index [BMI] 31.3 ± 2.8 kg m^-2, maximal oxygen uptake [V'O₂max] 41.5 ± 5.6 ml kg^-1 min^-1) ran a half, 30 km, or full marathon. Troponin I (cTnI), the n-terminal creatine kinase-myocardial band (CK-MB), pro b-type natriuretic peptide (NT-proBNP), lactate dehydrogenase (LDH), myoglobin, creatinine (CREA) and the estimated glomerular filtration rate (eGFR) were measured before (T0), immediately after (T1) and 3 days after the race (T2).

Results: The concentrations of cTnI, myoglobin, LDH, CK-MB and CREA significantly increased (P < 0.05), whereas eGRF decreased at T1 (P < 0.05). All the above parameters returned to baseline at T2, except for eGFR, which remained lower than that at T0 (P < 0.05). A positive association was observed between ΔCK-MB (%) and the time spent in Zone 3 during the race (R = 0.686, P = 0.014). The Δmyoglobin (%) was positively correlated with race time, race mean speed and time in Zone 3 (R = 0.574-0.862, P < 0.05). The ∆CREA values were moderately correlated with the race mean HR_MAX (%) and time spent in Zone 3 (%) (R = 0.514-0.610; P = 0.05). The ∆eGRF values were moderately inversely correlated with the time spent in Zone 3 (%) (R =  - 0.627; P < 0.05).

Conclusion: Changes in cardiac, muscular and renal inflammatory markers in trained men with obesity are consistent with those described in the literature in normal-weight individuals. Finally, running parameters, such as running time, average running intensity and time in Zone 3 appear to be responsible for the changes in cardiac, muscular and renal function markers after long-distance running.

Physical activity (PA) and exercise elicit adaptations and physiological responses in skeletal muscle, which are advantageous for preserving health and minimizing chronic illnesses. The complicated atmosphere of the exercise response can be attributed to hereditary and environmental variables. The primary cause of these adaptations and physiological responses is the transcriptional reactions that follow exercise, whether endurance- (ET) or resistance- training (RT). As a result, the essential metabolic and regulatory pathways and myogenic genes associated with skeletal muscle alter in response to acute and chronic exercise. Epigenetics is the study of the relationship between genetics and the environment. Exercise evokes signaling pathways that strongly alter myofiber metabolism and skeletal muscle physiological and contractile properties. Epigenetic modifications have recently come to light as essential regulators of exercise adaptations. Research has shown various epigenetic markers linked to PA and exercise. The most critical epigenetic alterations in gene transcription identified are DNA methylation and histone modifications, which are associated with the transcriptional response of skeletal muscle to exercise and facilitate the modification to exercise. Other changes in the epigenetic markers are starting to emerge as essential processes for gene transcription, including acetylation as a new epigenetic modification, mediated changes by methylation, phosphorylation, and micro-RNA (miRNA). This review briefly introduces PA and exercise and associated benefits, provides a summary of epigenetic modifications, and a fundamental review of skeletal muscle physiology. The objectives of this review are 1) to discuss exercise-induced adaptations related to epigenetics and 2) to examine the interaction between exercise metabolism and epigenetics.

Purpose: The present study examined the influence of endurance training on the morphological and functional heart adaptations in young athletes throughout a longitudinal 9-month follow-up period during the adolescent peak height velocity (PHV).

Methods: Thirty-six 13- to 15-year-old males (twenty-three triathletes and thirteen untrained peers) were evaluated before and after a 9-month period during PHV. Maximal oxygen uptake ( $\dot{V}{O}_{2max}$ ) and power at $\dot{V}{O}_{2max}$ were assessed during incremental cycling test. Resting echocardiography was performed to evaluate left ventricular (LV) morphology with standard parameters and using an original approach to assess LV shape. In addition, LV function was evaluated with advanced echocardiography tools including LV strains and myocardial work analyses from speckle-tracking echocardiography.

Results: Absolute $\dot{V}{O}_{2max}$ increased similarly in both groups but power at $\dot{V}{O}_{2max}$ only significantly increased in triathletes (from 232 ± 46 to 264 ± 46 W, p < 0.001). Maturation had a significant effect on LV morphology with an enlargement in both groups. Endurance training induced additional adaptations in young triathletes, i.e., a cardiac remodeling characterized by an increase in LV length (from 7.5 ± 0.7 to 8.2 ± 0.6 cm, p < 0.01). The stroke volume was greater in young triathletes compared to untrained peers but with a constant difference throughout the 9-month period. Finally, speckle-tracking echocardiography and myocardial work remained unchanged during the follow-up and similar between groups.

Conclusion: Endurance training induced morphological adaptations during the PHV period without significant adaptation in LV function as evidenced by the absence of specific changes in LV strains and myocardial work.

Purpose: This study investigated elite German athletes to (1) assess their serum 25(OH)D levels and the prevalence of insufficiency, (2) identify key factors influencing serum 25(OH)D levels, and (3) analyze the association between serum 25(OH)D levels and handgrip strength.

Methods: In this cross-sectional study, a total of 474 athletes (231 female), aged 13-39 years (mean 19.3 years), from ten Olympic disciplines were included. Serum 25(OH)D levels were analyzed via liquid chromatography-mass spectrometry, and 17 single nucleotide polymorphisms (SNPs) related to vitamin D metabolism were determined using leukocyte DNA. Grip strength was measured unimanually using a hand-held dynamometer. Multiple linear regressions were used to analyze the influence of SNPs, age, sex, season (summer vs. winter), and discipline (indoor vs. outdoor) on 25(OH)D status. Linear regression analyzed the relationship between handgrip strength and serum 25(OH)D levels.

Results: In total, 55.5% (n = 263) of athletes demonstrated insufficient serum 25(OH)D levels (< 30 ng/mL, < 75 nmol/L), with 16% (n = 76) showing levels below 20 ng/mL (50 nmol/L). After correction for multiple testing, significant influences on 25(OH)D levels were observed for the C allele of VDBP rs7041 (AC Genotype: $\hat{\beta }$  = 7.46, p < .001; CC Genotype: $\hat{\beta }$  = 6.23, p = .001). Age (all p < .01) and discipline (indoor vs. outdoor; all p < .05) also influenced serum 25(OH)D levels. Furthermore, serum 25(OH)D was positively associated with handgrip strength ( $\hat{\beta }$ = 0.01, p < .001).

Conclusion: A high prevalence of insufficient 25(OH)D levels (< 30 ng/mL, < 75 nmol/L) was observed. We identified certain genetic variants as well as age and discipline as predictors of serum 25(OH)D levels. This knowledge may guide individualized diagnostic, nutritional, and supplementation strategies.

The cortisol awakening response (CAR) is a discrete component of the circadian cortisol profile. Evidence suggests that the CAR is a deviation from the pre-awakening increase in cortisol concentration, although this has yet to be replicated. Therefore, the purpose of this study was to replicate this finding and to investigate further the extent to which the CAR is distinct from the circadian profile. Twelve participants completed 2 overnight visits in a sleep laboratory. An intravenous catheter was used to sample blood every 15 min. Participants were allowed to sleep ad libitum beginning at 2030 h, and blood sampling continued throughout the night until 1 h post-awakening, generating a total of 802 serum samples. Selected serum samples were assayed for cortisol, and piece-wise linear mixed-effect models tested the extent to which the increase in cortisol concentrations post-awakening deviated from the rise in cortisol concentrations from various pre-awakening periods. Results demonstrated that the CAR only significantly deviates from the pre-awakening rise when the pre-awakening linear rise is considered 4 (β = 1.79, 95% CI = 0.49-3.09, p = 0.007) or 5 (β = 1.79, 95% CI = 0.49-3.09, p = 0.007) h before waking. When including a non-linear change in cortisol during the 4-h pre-awakening period, the deviation from the diurnal profile for the CAR was no longer significant (β = 0.96, 95% CI = - 0.74-2.66, p = 0.266). These results partly agree and replicate previous evidence for the CAR being superimposed on the diurnal profile but continue to extend our teleological understanding of the functional role of the CAR.