European Journal of Applied Physiology最新文献

Purpose: Previous studies have shown delayed cardiac vagal reactivation after high-intensity endurance exercise when estimated with heart rate variability (HRV). However, the recovery dynamics of RR intervals (RRI) and HRV after a maximal incremental exercise test have been studied less in non-athletic population and especially in females. The main aim of the study was to examine the recovery dynamics of RRI and HRV immediately after a maximal cardiopulmonary exercise test (CPET) in adult females.

Methods: Twenty-eight healthy, novice recreational female runners (33.7 ± 4.2 years) were selected to participate in this study from a larger group of participants (Run RCT). RRIs were collected continuously during a controlled rest, a CPET on a treadmill and a 15-min controlled, passive recovery. Minute-by-minute recovery dynamics were analyzed.

Results: The dynamic phase of RRI and heart rate recovery (HRR) (from 192.2 ± 9.9 to 111.4 ± 2.4, P < 0.001) occurred during the first 4.5 min with HRR of 36 ± 10 beats during the first minute of the recovery. Resting heart rate was negatively associated (r =  - 0.53, P = 0.016) with HRR during the recovery. No recovery of root mean square of successive RRIs (RMSSD) was detected during the 15-min recovery. RMSSD was 15.0 ± 9.2% of resting values at the end of the recovery.

Conclusion: No recovery of vagal-derived HRV was detected immediately after a CPET in novice recreational female runners despite marked changes in sympathovagal balance, detected by rapid recovery of RRI during the first 5 min after exercise cessation.

This study compared heart rate variability (HRV) parameters of cardiovascular autonomic regulation between well-trained masters and young cyclists at rest, during and following a continuous cycle (CTS) protocol. Ten masters (age = 56 ± 5 years) and eight young (age = 26 ± 3 years) cyclists completed a 100 min experimental protocol consisting of a 60 min CTS cycling bout at 95% of Ventilatory Threshold 2 followed by 40 min of supine recovery. Beat-to-beat heart rate was measured continuously, and HRV parameters analysed at standardised 5 min intervals during rest, exercise and recovery. The root mean square of the successive differences (RMSSD), low-frequency power and high-frequency power parameters were corrected by division of the R-R interval (time domain), or R-R interval squared (frequency domain). Further, the RMSSD and RMSSD:RR for successive 60-s R-R intervals at the onset (0-10 min) and offset (60-70 min) of CTS exercise were analysed over 10-min periods. The natural logarithm (Ln) of skewed parameters was taken for analysis. Significant interaction effects (P < 0.05) for 5 min segments were found for (LnRMSSD, LnRMSSD:RR, LnHF and LnHF:RR². Masters cyclists demonstrated lower values of parasympathetic activity at rest and during recovery (15-20 min and 35-40 min) compared to younger cyclists. However, similar HRV responses were observed during exercise, including throughout the acute onset and offset periods (P > 0.05). This data shows that cardiac autonomic regulation during, or immediately following CTS exercise may not be influenced by age, but masters athletes may exhibit a lower baseline for parasympathetic activity.

Purpose: Human presence in space is increasingly frequent, but we must not forget that it is a hostile environment. We aimed to study the characteristics of experimental scenarios, to obtain data on human response to isolation, disruption of circadian rhythm and high levels of psychophysical stress.

Methods: In these experiments, we evaluated stress response in five young healthy subjects inside an earth-based moon-settlement-like habitat during a 1-week long analog astronaut mission. Wearable devices were used to monitor daily step count of the subjects, physical activity, heart rate during physical exercise and at rest, and sleep parameters. From saliva and urine samples collected every day at awakening, we studied oxy-inflammation biomarkers and hormones (stress and appetite) were studied too.

Results: At the end of the week, all subjects revealed an increase in oxidative stress and cortisol levels but no inflammation biomarkers variations, in conjunction with increasing time/daily exercise. Furthermore, a significant decrease in hours of sleep/day, sleep quality, and REM phase of sleep was recorded and correlated with the increase of reactive oxygen species.

Conclusion: Oxidative stress increased in a short period of time and may be attributed to the influence of psychological stress during confinement, as well as increased exercise and decreased amount of sleep. On a long-term basis, this could impact performance.

Purpose: Resistance exercise can attenuate muscular impairments associated with multiple sclerosis (MS), and blood flow restriction (BFR) may provide a viable alternative to prescribing heavy training loads. The purpose of this investigation was to examine the progression of upper and lower body low-load (30% of one-repetition maximum [1RM]) resistance training (RT) with BFR applied intermittently during the exercise intervals (RT + BFR) versus volume-matched heavy-load (65% of 1RM) RT.

Methods: Men and women with MS (n = 16) were randomly assigned to low-load RT + BFR (applied intermittently) or heavy-load RT and completed 12 weeks (2 × /week) of RT that consisted of bilateral chest press, seated row, shoulder press, leg press, leg extension, and leg curl exercises. Exercise load, tonnage, and rating of perceived exertion were assessed at baseline and every 6 weeks.

Results: Training load increased to a greater extent and sometimes earlier for RT + BFR (57.7-106.3%) than heavy-load RT (42.3-54.3%) during chest press, seated row, and leg curl exercises, while there were similar increases (63.5-101.1%) for shoulder press, leg extension, and leg press exercises. Exercise tonnage was greater across all exercises for RT + BFR than heavy-load RT, although tonnage only increased during the chest press (70.7-80.0%) and leg extension (89.1%) exercises. Perceptions of exertion (4.8-7.2 au) and compliance (97.9-99.0%) were similar for both interventions.

Conclusion: The training-induced increases in load, high compliance, and moderate levels of exertion suggested that RT + BFR and heavy-load RT are viable interventions among people with MS. RT + BFR may be a preferred modality if heavy loads are not well tolerated and/or to promote early-phase training responses.

Purpose: This study aimed to establish a new threshold parameter called the physical working capacity at pain intensity threshold (PWC_PIT) using a pain intensity scale and mathematical methods similar to those used to develop the physical working capacity at oxygen consumption threshold (PWC_VO2) and physical working capacity at heart rate threshold (PWC_HRT). The study had two objectives: (i) to examine the relationship between PWC_PIT and traditional PWC measures and (ii) to explore the physiological mechanisms underlying the relationship between pain perception and capacity thresholds.

Methods: Fourteen male volunteers (age 21 ± 2 years, height 176 ± 6 cm, weight 76 ± 9 kg, VO_2peak 37.8 ± 7.8 ml/kg/min^-1) underwent an incremental exhaustion test and four 8-min randomly ordered work bouts on different days at 70-100% peak power output (119-320 W) to establish their PWC_PIT, PWC_HRT and PWC_VO2. One-way repeated-measures ANOVA with Bonferroni post hoc tests and a zero-order correlation matrix were used to analyze these thresholds.

Results: PWC_PIT significantly correlated with PWC_HRT (r = 0.88, P < 0.001), PWC_VO2 (r = 0.84, P < 0.001), and gas exchange threshold (GET) (r = 0.7, P = 0.006).

Conclusion: The model for estimating PWC_HRT and PWC_VO2 can be applied to determine the PWC_PIT. By examining how PWC_PIT aligns with, differs from, or complements existing PWC threshold measures, researchers may provide a more comprehensive understanding of the factors that govern endurance performance.

Purpose: To investigate the acute effects of eccentric-based resistance exercise and sex-hormone fluctuations on P1NP and β-CTX-1 concentrations in premenopausal females.

Methods: Nine eumenorrheic females and ten oral contraceptive (OC) users performed eccentric-based resistance exercise, consisted of 10 × 10 repetitions of parallel back squats with a 4-s eccentric phase, in the early-follicular (EFP), late-follicular (LFP) and mid-luteal (MLP) phases of the menstrual cycle (MC) or in the withdrawal (WP) and active pill-taking (APP) phases of the OC cycle.

Results: 17β-oestradiol (pg·ml^-1) was lower in EFP (36.63 ± 29.93) compared to LFP (224.81 ± 233.81; p ≤ 0.001) and MLP (161.45 ± 110.08; p < 0.001) and higher in WP (24.857 ± 29.428) compared to APP (12.72 ± 13.36; p = 0.004). Progesterone (ng·ml-1) was higher in MLP (8.30 ± 5.23) compared to EFP (0.33 ± 0.33; p < 0.001) and LFP (0.21 ± 0.18; p < 0.001), no significant differences were observed between the WP and APP. In eumenorrheic females, β-CTX-1 (ng·ml^-1) was lower in MLP (0.395 ± 0.126) compared to LFP (0.472 ± 0.137; p = 0.044). Comparing MC vs OC phases, eumenorrheic females had higher P1NP levels (ng·ml^-1) compared to OC users: EFP (62.54 ± 13.13) vs APP (50.69 ± 8.91; p = 0.034), LFP (67.32 ± 18.96) vs WP (52.16 ± 10.72; p = 0.047), LFP vs APP (p = 0.025), MLP (67.51 ± 19.34; p = 0.049) vs WP, MLPvsAPP (p = 0.027). Exercise time effect showed lower β-CTX-1 concentrations 2 h post-exercise (MC: 0.376 ± 0.114, p < 0.001; OC: 0.340 ± 0.156, p = 0.030) compared to pre-exercise (MC: 0.485 ± 0.137; OC: 0.428 ± 0.188) in all participants.

Conclusions: β-CTX-1 concentrations were lower in the mid-luteal phase, emphasising the importance of standardizing bone marker measurements to a specific MC phase. OC users exhibited reduced P1NP levels, underscoring the need to investigate synthetic and endogenous hormones' impact on long-term bone structure and strength. Trial registration The study was registered at Clinicaltrials.gov NCT04458662 on 2 July 2020.

Purpose: The aim of this study was to determine whether a soccer match affects the rapid force-generating capacity of the hamstring muscles, given their key role in both horizontal ground reaction force production during sprint biomechanics, and in the deceleration of the shank during the late swing phase, where rapid force production is essential owing to time constraints. Therefore, the research objective was to determine soccer match-induced hamstrings residual fatigue and recovery through rate of torque development (RTD) and associated biochemical parameters.

Methods: The recovery kinetics of hamstrings RTD metrics by the 90°_hip:20°_knee test, together with serum biomarkers (creatine kinase, mitochondrial creatine kinase, transaminases, malondialdehyde, irisin), were assessed in 19 male, regional first-division soccer players (age = 20.9 ± 2.0 years, mass = 72.6 ± 11.9 kg, height = 175.9 ± 6.9 cm [mean ± SD]), before a soccer match (MD) and post-24 h (MD₊₁), post-48 h (MD₊₂) and post-72 h (MD₊₃), through a repeated measures design.

Results: Early RTD to 50 ms (p < 0.001, g = -1.24) and 100 ms (p < 0.001, g = -1.06) remained unrecovered on MD₊₃ in both hamstring muscles. However, maximal voluntary isometric contraction (MVIC) torque of the dominant and non-dominant hamstrings was unrecovered on MD₊₂ (p = 0.004, g = -0.91; and p = 0.002, g = -0.98, respectively) and recovered on MD₊₃ (p = 0.057 and p = 0.070, respectively). Further, neuromuscular deficits were coupled with myocyte structural (p = 0.002, g = 1.11) and mitochondrial damage (p = 0.004, g = 0.92) biomarkers.

Conclusion: Based in the findings, early RTD_0-50 and RTD_0-100 monitoring, through the 90°_hip:20°_knee IPC test, is a cost-effective method for assessing soccer match-induced hamstring muscles residual fatigue and recovery. Overall, soccer match-induced hamstring residual fatigue is not recovered within a 3-day recovery period. Practitioners can use rapid force production metrics through isometric assessments, providing a simple, non-exhaustive tool, for assessing residual fatigue status during congested competitive periods, to comprehensively balance muscle recovery with optimizing training.

Purpose: To determine the effect of carbohydrate ingestion during prolonged exercise on durability of the moderate-to-heavy-intensity transition and severe-intensity performance.

Methods: Twelve trained cyclists and triathletes (10 males, 2 females; $\dot{V}{\text{O}}_2$ peak, 59 ± 5 mL kg^-1 min^-1; training volume, 14 ± 5 h week^-1) performed an incremental test and 5-min time trial (TT) without prior exercise (PRE), and after 150 min of moderate-intensity cycling, with (POST_CHO) and without (POST_CON) carbohydrate ingestion.

Results: Power output at the first ventilatory threshold (VT₁) was lower in POST_CHO (225 ± 36 W, ∆ -3 ± 2%, P = 0.027, n = 11) and POST_CON (216 ± 35 W, ∆ -6 ± 4%, P = 0.001, n = 12) than PRE (229 ± 37 W, n = 12), and lower in POST_CON than POST_CHO (∆ -7 ± 9 W, ∆ -3 ± 4%, P = 0.019). Mean power output in the 5-min TT was lower in POST_CHO (351 ± 53 W, ∆ -4 ± 3%, P = 0.025) and POST_CON (328 ± 63 W, ∆ -10 ± 10%, P = 0.027) than PRE (363 ± 55 W), but POST_CHO and POST_CON were not significantly different (∆ 25 ± 37 W, ∆ 9 ± 13%, P = 0.186). Blood glucose concentration was maintained in POST_CHO, and was significantly lower at the 120 and 150-min timepoint in POST_CON (P < 0.05).

Conclusion: These data suggest that durability of the moderate-to-heavy-intensity transition is improved with carbohydrate ingestion. This has implications for training programming and load monitoring.