Validity of the acute recovery and stress scale: training monitoring of the German junior national field hockey team

The aim of the present study was to examine the sensitivity of the Acute Recovery and Stress Scale (ARSS). This new psychometric questionnaire was developed to assess the physical, mental, emotional, and overall recovery and stress states of athletes. During a five-day field hockey training camp of the German Junior National Field Hockey Team (n = 25) the ARSS was administered every morning and evening. The study indicated swift reactions of the scores of the physical and general factors as well as stability of scores for the emotional factors in accordance with the training schedule. The straining effect of the camp was best reflected by the adaptations of the scales Physical Performance Capability (F (2.9, 60.3) = 10.0, p < 0.001) and Muscular Stress (F (4, 84) = 16.7, p < 0.001). The results support the ability of the ARSS to monitor recovery-stress (im-) balances in this sample. Thus, the questionnaire has shown to be a sensitive and practical tool that might be suitable for elite sport settings

Muscle mechanical properties of strength and endurance athletes and changes after one week of intensive training

The study investigates whether tensiomyography (TMG) is sensitive to differentiate between strength and endurance athletes, and to monitor fatigue after either one week of intensive strength (ST) or endurance (END) training. Fourteen strength (24.1 +/- 2.0 years) and eleven endurance athletes (25.5 +/- 4.8 years) performed an intensive training period of 6 days of ST or END, respectively. ST and END groups completed specific performance tests as well as TMG measurements of maximal radial deformation of the muscle belly (Dm), deformation time between 10% and 90% Dm (Tc), rate of deformation development until 10% Dm (V10) and 90% Dm (V90) before (baseline), after training period (post1), and after 72 h of recovery (post2). Specific performance of both groups decreased from baseline to post1 (P < 0.05) and returned to baseline values at post2 (P < 0.05). The ST group showed higher countermovement jump (P < 0.05) and shorter Tc (P < 0.05) at baseline. After training, Dm, V10, and V90 were reduced in the ST (P < 0.05) while TMG changes were less pronounced in the END. TMG could be a useful tool to differentiate between strength and endurance athletes, and to monitor fatigue and recovery especially in strength training. (C) 2016 Elsevier Ltd. All rights reserved

How does a short, interrupted recovery break affect performance and how is it assessed? A study on acute effects

A recovery process with optimal prerequisites, which is interrupted, is termed disrupted recovery. Whether this process has an influence on performance-related factors needs to be investigated. Therefore, the aim of this study was to examine how a short disturbance of a recovery phase is assessed and whether subsequent repeated sprint performance is affected by it. A quasi-experimental 2x2-factors cross-over design with 34 sport science undergraduate students (age 20.3 ± 2.1) was applied. Factors were the type of intervention (power nap vs. systematic breathing; between-subjects) and the experimental condition (disturbed vs. non-disturbed break; within-subjects). Repeated sprint performance was measured through 6x4 s sprint protocols (with 20 s breaks) before and after a 25 min recovery break on two test days. Subjective evaluation of the interventions was measured through the Short Recovery and Stress Scale and a manipulation check assessing whether participants experienced the recovery phase as efficacious and pleasant. Regarding the objective data, no significant difference between sprint performances in terms of average peak velocity (m/s) on the NMT was found. The manipulation check revealed that disturbed conditions were rated significantly lower than regular conditions in terms of appreciation, t(31) = 3.09, p = .01. Short disturbances of recovery do not seem to affect subsequent performance; nevertheless, participants assessed disturbed conditions more negative than regular conditions. In essence, the findings indicate a negligible role of short interruptions on an objective level. Subjectively, they affected the performance-related assessment of the participants and should be treated with caution

Monitoring training and recovery responses with heart rate measures during standardized warm-up in elite badminton players

Purpose To investigate short-term training and recovery-related effects on heart rate during a standardized submaximal running test. Methods Ten elite badminton players (7 females and 3 males) were monitored during a 12-week training period in preparation for the World Championships. Exercise heart rate (HRex) and perceived exertion were measured in response to a 5-min submaximal shuttle-run test during the morning session warm-up. This test was repeatedly performed on Mondays after 1–2 days of pronounced recovery (‘recovered’ state; reference condition) and on Fridays following 4 consecutive days of training (‘strained’ state). In addition, the serum concentration of creatine kinase and urea, perceived recovery–stress states, and jump performance were assessed before warm-up. Results Creatine kinase increased in the strained compared to the recovered state and the perceived recovery–stress ratings decreased and increased, respectively (range of average effects sizes: |d| = 0.93–2.90). The overall HRex was 173 bpm and the observed within-player variability (i.e., standard deviation as a coefficient of variation [CV]) was 1.3% (90% confidence interval: 1.2% to 1.5%). A linear reduction of -1.4% (-3.0% to 0.3%) was observed in HRex over the 12-week observational period. HRex was -1.5% lower (-2.2% to -0.9%) in the strained compared to the recovered state, and the standard deviation (as a CV) representing interindividual variability in this response was 0.7% (-0.6% to 1.2%). Conclusions Our findings suggest that HRex measured during a standardized warm-up can be sensitive to short-term accumulation of training load, with HRex decreasing on average in response to consecutive days of training within repeated preparatory weekly microcycles. From a practical perspective, it seems advisable to determine intra-individual recovery–strain responses by repeated testing, as HRex responses may vary substantially between and within players

Tensiomyographic Markers Are Not Sensitive for Monitoring Muscle Fatigue in Elite Youth Athletes: A Pilot Study

Objective: Tensiomyography (TMG) is an indirect measure of a muscle's contractile properties and has the potential as a technique for detecting exercise-induced skeletal muscle fatigue. Therefore, the aim of this study was to assess the sensitivity of tensiomyographic markers to identify reduced muscular performance in elite youth athletes.Methods: Fourteen male junior tennis players (age: 14.9 ± 1.2 years) with an international (International Tennis Federation) ranking position participated in this pre-post single group trial. They completed a 4-day high-intensity interval training (HIT) microcycle, which was composed of seven training sessions. TMG markers; countermovement jump (CMJ) performance (criterion measure of fatigue); delayed onset muscle soreness; and perceived recovery and stress were measured 24 h before and after the training program. The TMG measures included maximal radial deformation of the rectus femoris muscle belly (Dm), contraction time between 10 and 90% Dm (Tc) and the rate of deformation until 10% (V10) and 90% Dm (V90), respectively. Diagnostic characteristics were assessed with a receiver-operating curve (ROC) analysis and a contingency table, in which the area under the curve (AUC), Youden's index, sensitivity, specificity, and the diagnostic effectiveness (DE) of TMG measures were reported. A minimum AUC of 0.70 and a lower confidence interval (CI) &gt;0.50 classified “good” diagnostic markers to assess performance changes.Results: Twenty-four hours after the microcycle, CMJ performance was observed to be significantly (p &lt; 0.001) reduced (Effect Size [ES] = −0.68), and DOMS (ES = 3.62) as well as perceived stress were significantly (p &lt; 0.001) increased. In contrast, Dm (ES = −0.35), Tc (ES = 0.04), V10 (ES = −0.32), and V90 (ES = −0.33) remained unchanged (p &gt; 0.05) throughout the study. ROC analysis and the data derived from the contingency table revealed that none of the tensiomyographic markers were effective diagnostic tools for detecting impaired muscular performance in elite youth athletes (AUC, 95% CI, DE%; Dm: 0.46, 0.15–0.77, 35.7%; Tc: 0.29, 0.03–0.59, 35.7%; V10: 0.71, 0.27–1.00, 35.7%; V90: 0.37, 0.10–0.65, 35.7%).Conclusion: The tensiomyographic parameters that were assessed in this study were not sensitive enough to detect muscular performance changes in elite youth athletes.However, due to the preliminary nature of the study, further research is needed to investigate the sensitivity of TMG in this population

Recovery-Stress Response of Blood-Based Biomarkers

The purpose of this study was to investigate blood-based biomarkers and their regulation with regard to different recovery-stress states. A total of 35 male elite athletes (13 badminton, 22 soccer players) were recruited, and two venous blood samples were taken: one in a ‘recovered’ state (REC) after a minimum of one-day rest from exercise and another one in a ‘non-recovered’ state (NOR) after a habitual loading microcycle. Overall, 23 blood-based biomarkers of different physiologic domains, which address inflammation, muscle damage, and tissue repair, were analyzed by Luminex assays. Across all athletes, only creatine kinase (CK), interleukin (IL-) 6, and IL-17A showed higher concentrations at NOR compared to REC time points. In badminton players, higher levels of CK and IL-17A at NOR were found. In contrast, a higher value for S100 calcium-binding protein A8 (S100A8) at REC was found in badminton players. Similar differences were found for BDNF in soccer players. Soccer players also showed increased levels of CK, and IL-6 at NOR compared to REC state. Several molecular markers were shown to be responsive to differing recoverystress states, but their suitability as biomarkers in training must be further validated

Can cold water immersion enhance recovery in elite Olympic weightlifters? An individualized perspective

We investigated whether cold water immersion following intensive training sessions can enhance recovery in elite Olympic weightlifters, taking into account each athlete's individual response pattern. The entire German male Olympic weightlifting national team participated in the study (n=7), ensuring collection of data from elite athletes only. Using a randomized cross-over design, the athletes went through two high intensity training microcycles consisting of five training sessions that were either followed by a cold water immersion or passive recovery. Barbell speed in a snatch pull movement, blood parameters as well as subjective ratings of general fatigue and recovery were assessed throughout the study. Physical performance at two snatch pull intensities (85% 1RM: -0.15% vs. -0.22%, P=0.94; 90% 1RM: -0.7% vs. +1.23%, P=0.25) did not differ significantly (condition x time). While questionnaires revealed a significant decline in ratings of overall recovery (

Effects of daily static stretch training over 6 weeks on maximal strength, muscle thickness, contraction properties, and flexibility

PurposeStatic stretch training (SST) with long stretching durations seems to be sufficient to increase flexibility, maximum strength (MSt) and muscle thickness (MTh). However, changes in contraction properties and effects on muscle damage remain unclear. Consequently, the objective of the study was to investigate the effects of a 6-week self-performed SST on MSt, MTh, contractile properties, flexibility, and acute response of creatine kinase (CK) 3 days after SST.MethodsForty-four participants were divided into a control (CG, n = 22) and an intervention group (IG, n = 22), who performed a daily SST for 5 min for the lower limb muscle group. While isometric MSt was measured in leg press, MTh was examined via sonography and flexibility by functional tests. Muscle stiffness and contraction time were measured by tensiomyography on the rectus femoris. Additionally, capillary blood samples were taken in the pretest and in the first 3 days after starting SST to measure CK.ResultsA significant increase was found for MSt (p &lt; 0.001, η2 = 0.195) and flexibility in all functional tests (p &lt; 0.001, η2 &gt; 0.310). Scheffé post hoc test did not show significant differences between the rectus femoris muscle inter- and intragroup comparisons for MTh nor for muscle stiffness and contraction time (p &gt; 0.05, η2 &lt; 0.100). Moreover, CK was not significantly different between IG and CG with p &gt; 0.05, η2 = 0.032.DiscussionIn conclusion, the increase in MSt cannot be exclusively explained by muscular hypertrophy or the increased CK-related repair mechanism after acute stretching. Rather, neuronal adaptations have to be considered. Furthermore, daily 5-min SST over 6 weeks does not seem sufficient to change muscle stiffness or contraction time. Increases in flexibility tests could be attributed to a stretch-induced change in the muscle–tendon complex

miRNAs and sports: tracking training status and potentially confounding diagnoses

Background: The dependency of miRNA abundance from physiological processes such as exercises remains partially understood. We set out to analyze the effect of physical exercises on miRNA profiles in blood and plasma of endurance and strength athletes in a systematic manner and correlated differentially abundant miRNAs in athletes to disease miRNAs biomarkers towards a better understanding of how physical exercise may confound disease diagnosis by miRNAs. Methods: We profiled blood and plasma of 29 athletes before and after exercise. With four samples analyzed for each individual we analyzed 116 full miRNomes. The study set-up enabled paired analyses of individuals. Affected miRNAs were investigated for known disease associations using network analysis. Results: MiRNA patterns in blood and plasma of endurance and strength athletes vary significantly with differences in blood outreaching variations in plasma. We found only moderate differences between the miRNA levels before training and the RNA levels after training as compared to the more obvious variations found between strength athletes and endurance athletes. We observed significant variations in the abundance of miR-140-3p that is a known circulating disease markers (raw and adjusted p value of 5 × 10−12 and 4 × 10−7). Similarly, the levels of miR-140-5p and miR-650, both of which have been reported as makers for a wide range of human pathologies significantly depend on the training mode. Among the most affected disease categories we found acute myocardial infarction. MiRNAs, which are up-regulated in endurance athletes inhibit VEGFA as shown by systems biology analysis of experimentally validated target genes. Conclusion: We provide evidence that the mode and the extent of training are important confounding factors for a miRNA based disease diagnosis