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

Individual Patterns in Blood-Borne Indicators of Fatigue - Trait or Chance

© 2016 National Strength and Conditioning Association. Julian, R, Meyer, T, Fullagar, HHK, Skorski, S, Pfeiffer, M, Kellmann, M, Ferrauti, A, and Hecksteden, A. Individual patterns in blood-borne indicators of fatigue - trait or chance. J Strength Cond Res 31(3): 608-619, 2017 - Blood-borne markers of fatigue such as creatine kinase (CK) and urea (U) are widely used to fine-tune training recommendations. However, predictive accuracy is low. A possible explanation for this dissatisfactory characteristic is the propensity of athletes to react to different patterns of fatigue indicators (e.g., predominantly muscular [CK] or metabolic [U]). The aim of the present trial was to explore this hypothesis by using repetitive fatigue-recovery cycles. A total of 22 elite junior swimmers and triathletes (18 ± 3 years) were monitored for 9 weeks throughout 2 training phases (low-intensity, high-volume [LIHV] and high-intensity, low-volume [HILV] phases). Blood samples were collected each Monday (recovered) and Friday (fatigued) morning. From measured values of CK, U, free-testosterone (FT), and cortisol (C) as determined in the rested and fatigued state, respectively, Monday-Friday differences (Δ) were calculated and classified by magnitude before calculation of ratios (ΔCK/ΔU and ΔFT/ΔC). Coefficient of variation (CV) was calculated as group-based estimates of reproducibility. Linear mixed modeling was used to differentiate inter- and intraindividual variability. Consistency of patterns was analyzed by comparing with threshold values (1.1 for all weeks). Reproducibility was very low for fatigue-induced changes (CV ≥ 100%) with interindividual variation accounting for 45-60% of overall variability. Case-wise analysis indicated consistent ΔCK/ΔU patterns for 7 individuals in LIHV and 7 in HILV; 5 responded consistently throughout. For ΔFT/ΔC the number of consistent patterns was 2 in LIHV and 3 in HILV. These findings highlight the potential value of an individualized and multivariate approach in the assessment of fatigue

Relevance of force-velocity and change of direction assessments for the ranking position in elite junior tennis players

PurposeThis study aimed to correlate sprint mechanical parameters (SMP) of a linear sprint (LS) and a tennis specific modified 505 (Tm505) change of direction (CoD) test obtained with a motorized resistance device (MRD) to the current tennis ranking position (RP).Methods107 male and 86 female elite junior tennis players nationally ranked in the German Tennis Federation between 10 and 18 years participated in the study. According to their age at peak height velocity (PHV), players were divided into pre-PHV, circa-PHV, and post-PHV groups. SMP were derived from instantaneous time-velocity data of two 20 m all-out LS measured with 333 Hz. Further, mean values from two Tm505 trials with constant 3 kg loading over acceleration-deceleration (1a) and reacceleration (1b) phases were measured with an MRD. SMP of LS and CoD measurements were partially correlated with the current RP in the overall national ranking by controlling for biological maturation.ResultsLow to moderate correlations (rs = −0.1 to −0.3) were found between SMP and the RP in all male and female age groups. Correlations of the CoD measurements were overall more pronounced, particularly in girls (rs = −0.44). All linear SMP, like maximal theoretical force (F0; N/kg), and maximal theoretical velocity (v0; m/s), maximal power (Pmax; W/kg), improved over maturation for both genders with Pmax being most important for sprint performance. Further, Pmax was shown to correlate with the girls ranking position (rs = −0.31). During the Tm505, matured players achieved significantly faster overall total and CoD times. Positioning of CoM before CoD enlarged over maturation and was found to correlate to the RP in both sexes. In addition, nearly all SMP significantly correlated to the primary performance outcomes in the Tm505 test in both genders (r = −0.3 to −0.6).ConclusionCoD performance has a moderate and higher impact on tennis performance compared to LS. CoD performance as well as Pmax achieved a higher relevance for the ranking position predominantly in girls compared to boys. Hence, particularly Pmax as well as the transfer to on-court CoD motor skills should be a central training goal in elite junior tennis players besides technical skills and should depend on maturation status and gender

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

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

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

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

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