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

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

Belastungs- und Erholungssteuerung im High-Intensity Ausdauertraining

Die Leistungsentwicklung im Rahmen eines High-Intensity Ausdauertrainings (HIT) steht in ständiger Wechselwirkung mit den durch die hohen Reizintensitäten ausgelösten Ermüdungs- und Erholungsprozesse. Erfolgt keine adäquate Steuerung von Belastung und Erholung, nimmt das Risiko für chronische Überlastungsreaktionen zu. Daher war das Ziel dieser Dissertation, evidenzbasierte Praxisleitlinien für eine Belastungs- und Erholungssteuerung im HIT zu erarbeiten. Die Ergebnisse zeigten, dass (1.) die akuten Belastungs- und mittelfristigen Ermüdungsreaktionen zwischen unterschiedlichen praxisüblichen HIT-Protokollen teils erheblich variieren, (2.) die Sprungleistung, Muskelkontraktilität, Creatinkinase-Aktivität sowie eine subjektive Empfindensdiagnostik praktikable und potentiell sensitive Parameter zur Diagnostik von Beanspruchung und Ermüdung im HIT sind und (3.) eine aktive Erholung weder messbaren Vor- noch Nachteil hinsichtlich des Regenerationsprozesses nach HIT besitzt

Regenerationsinterventionen und deren Wirksamkeit im Sport

Das Habilitationsvorhaben widmete sich der Frage nach der Evidenz der Wirksamkeit von Regenerationsinterventionen im Sport. Die Ergebnisse der durchgeführten Studien ergaben eine auf gruppenstatistischer Ebene überwiegend geringe bis triviale Evidenz der Wirksamkeit der untersuchten Interventionen. Allerdings waren einzelne Athletinnen und Athleten auffällig, die durch die untersuchten Regenerationsmaßnahmen gegenüber einer Kontrollsituation relevante Vorteile und in seltenen Fällen auch Nachteile erfahren haben und bei denen sich diese Effekte bei mehrfacher Regenerationsanwendung wiederholt zeigten. Außerdem erreichten die meisten Maßnahmen im Mittel wie im Einzelfall einen größeren Effekt auf psychometrische bzw. subjektive Ermüdungsmarker, während die Effekte auf objektive Messwerte deutlich geringer waren. Trotz der im Schnitt geringen bis trivialen Effektstärken können gezielt eingesetzte Regenerationsinterventionen im Leistungs- und Spitzensport sowie im Einzelfall relevant sein (z. B. zur Einstellung von Wohlbefinden und Leistungsbereitschaft sowie zur kurzfristigen Verringerung von Muskelschmerzen)

Age- and Sex-Related Differences in Recovery From High-Intensity and Endurance Exercise: A Brief Review

Postexercise recovery is a fundamental component for continuous performance enhancement. Due to physiological and morphological changes in aging and alterations in performance capacity, athletes of different ages may recover at different rates from physical exercise. Differences in body composition, physiological function, and exercise performance between men and women may also have a direct influence on restoration processes. Purpose: This brief review examines current research to indicate possible differences in recovery processes between male and female athletes of different age groups. The paper focuses on postexercise recovery following sprint and endurance tests and tries to identify determinants that modulate possible differences in recovery between male and female subjects of different age groups. Results: The literature analysis indicates age- and sex-dependent differences in short- and long-term recovery. Short-term recovery differs among children, adults, and masters. Children have shorter lactate half-life and a faster cardiac and respiratory recovery compared to adults. Additionally, children and masters require shorter recovery periods during interval bouts than trained adults. Trained women show a slower cardiac and respiratory recovery compared to trained men. Long-term recovery is strongly determined by the extent of muscle damage. Trained adults tend to have more extensive muscle damage compared to masters and children. Conclusion: The influence of age and sex on the recovery process varies among the different functional systems and depends on the time of the recovery processes. Irrespective of age and sex, the performance capacity of the individual determines the recovery process after high-intensity and endurance exercise

Effect of repeated active recovery during a high-intensity shock microcycle on markers of fatigue

Purpose: To investigate the effect of repeated use of active recovery during a 4-d shock microcycle with 7 high-intensity interval-training (HIT) sessions on markers of fatigue. Methods: Eight elite male junior tennis players (age 15.1 +/- 1.4 y) with an international ranking between 59 and 907 (International Tennis Federation) participated in this study. After each training session, they completed 15 min of either moderate jogging (active recovery [ACT]) or passive recovery (PAS) with a crossover design, which was interrupted by a 4-mo washout period. Countermovement-jump (CMJ) height, serum concentration of creatine kinase (CK), delayed-onset muscle soreness (DOMS), and perceived recovery and stress (Short Recovery and Stress Scale) were measured 24 h before and 24 h after the training program. Results: The HIT shock microcycle induced a large decrease in CMJ performance (ACT: effect size [ES] = -1.39, P .05; PAS: ES = 0.81, P > .05), DOMS (ACT: ES = 2.02, P < .05.; PAS: ES = 2.17, P < .05), and perceived stress (ACT: ES = 1.98, P < .05; PAS: ES = 3.06, P < .05), compared with the values before the intervention. However, no significant recovery intervention x time interactions or meaningful differences in changes were noted in any of the markers between ACT and PAS. Conclusions: Repeated use of individualized ACT, consisting of 15 min of moderate jogging, after finishing each training session during an HIT shock microcycle did not affect exercise-induced fatigue

Markers for routine assessment of fatigue and recovery in male and female team sport athletes during high-intensity interval training

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