Reliability of the parameters of the power-duration relationship using maximal effort time-trials under laboratory conditions

The purpose of this study was to assess the reliability of critical power (CP) and the total amount of work accomplished above CP (W´) across repeated tests using ecological valid maximal effort time-trials (TTs) under laboratory conditions. After an initial incremental exercise test, ten well-trained male triathletes (age: 28.5 ± 4.7 yrs; body mass: 73.3 ± 7.9 kg; height: 1.80 ± 0.07 m; maximal aerobic power (MAP): 328.6 ± 41.2 W) performed three testing sessions (Familiarization, Test I and Test II) each comprising three TTs (12 min, 7 min and 3 min with a passive recovery of 60 min between trials). CP and W´ were determined using a linear regression of power vs. the inverse of time (1/t) (P = W´ ∙ 1/t + CP). A repeated measure ANOVA was used to detect differences in CP and W´ and reliability was assessed using the intra-class correlation coefficient (ICC) and the coefficient of variation (CoV). CP and W´ values were not significantly different between repeated tests (P = 0.171 and P = 0.078 for CP and W´, respectively). The ICC between Familiarization and Test I was r = 0.86 (CP) and r = 0.58 (W´) and between Tests I and II it was r = 0.94 (CP) and r = 0.95 (W´). The CoV notably decreased from 4.1% to 2.6% and from 25.3% to 8.2% for CP and W´ respectively. Despite the non-significant differences for both parameter estimates between the repeated tests, ICC and CoV values improved notably after the Familiarization trial. Our novel findings indicate that for both, CP and W´ post familiarization ICC and CoV values indicated high reliability. It is therefore advisable to familiarize well-trained athletes when determining the power-duration relationship using TTs under laboratory conditions

Different durations within the method of best practice affect the parameters of the speed-duration relationship

The aim of the study was to determine whether estimates of the speed-duration relationship are affected using different time-trial (TT) field-based testing protocols, where exhaustive times were located within the generally recommended durations of 2 to 15 min. Ten triathletes (mean±SD age: 31.0±5.7yrs; height: 1.81±0.05m; body mass: 76.5±6.8kg) performed two randomly assigned field-tests to determine critical speed (CS) and the total distance covered above CS (D´). CS and D´ were obtained using two different protocols comprising three TT that were interspersed by 60 min passive rest. The TTs were 12, 7, and 3 min in Protocol I and 10, 5, and 2 min in Protocol II. A linear relationship of speed vs. the inverse of time (s=D´x1/t+CS) was used to determine parameter estimates. Significant differences were found for CS (P=.026), but not for D´ (P=.123). The effect size for CS (d=.305) was considered small, whilst that for D´ was considered moderate (d=.742). CS was significantly correlated between protocols (r=.934; P<.001), however, no correlation was found for D´ (r=.053; P=.884). The 95% limits of agreement were ±0.28m∙s-1 and ±73.9m for CS and D´, respectively. These findings demonstrate that the choice of exhaustive times within commonly accepted durations, results in different estimates of CS and D´ and thus protocols cannot be used interchangeably. The use of a consistent protocol is therefore recommended, when investigating or monitoring the speed-duration relationship estimates in well-trained athletes

TBK1 is part of a galectin 8 dependent membrane damage recognition complex and drives autophagy upon Adenovirus endosomal escape.

Intracellular pathogens cause membrane distortion and damage as they enter host cells. Cells perceive these membrane alterations as danger signals and respond by activating autophagy. This response has primarily been studied during bacterial invasion, and only rarely in viral infections. Here, we investigate the cellular response to membrane damage during adenoviral entry. Adenoviruses and their vector derivatives, that are an important vaccine platform against SARS-CoV-2, enter the host cell by endocytosis followed by lysis of the endosomal membrane. We previously showed that cells mount a locally confined autophagy response at the site of endosomal membrane lysis. Here we describe the mechanism of autophagy induction: endosomal membrane damage activates the kinase TBK1 that accumulates in its phosphorylated form at the penetration site. Activation and recruitment of TBK1 require detection of membrane damage by galectin 8 but occur independently of classical autophagy receptors or functional autophagy. Instead, TBK1 itself promotes subsequent autophagy that adenoviruses need to take control of. Depletion of TBK1 reduces LC3 lipidation during adenovirus infection and restores the infectivity of an adenovirus mutant that is restricted by autophagy. By comparing adenovirus-induced membrane damage to sterile lysosomal damage, we implicate TBK1 in the response to a broader range of types of membrane damage. Our study thus highlights an important role for TBK1 in the cellular response to adenoviral endosome penetration and places TBK1 early in the pathway leading to autophagy in response to membrane damage

The oral contraceptive cycle and its influences on maximal and submaximal endurance parameters in elite handball players

The usage of the oral contraceptive pill is widespread among athletes of various levels. However, there is limited knowledge on how the intake of the pill alters the submaximal and maximal endurance parameters between the oral contraceptive phases. Therefore, the aim of this study was to examine potential differences between the pill intake and withdrawal phase on endurance-related parameters in first-division handball players. In total, 15 female team handball players performed two graded exercise tests until volitional exhaustion on a motorized treadmill. Tests were performed during the pill intake (days 16–17) and withdrawal phase (day 2–3). Throughout the test, respiratory gases were measured breath-by-breath, and the heart rate was measured continuously. Before and after the graded exercise test, blood samples were obtained in order to assess the blood lactate concentration. Before each test, venous blood samples were taken to determine endogenous sex hormone levels. Ventilatory parameters (V˙O2, V˙CO2, and V˙E, and respiratory equivalents for V˙O2 and V˙CO2) were measured, and the oxidation of fat and carbohydrates was calculated. A paired-sample t-test was used to assess differences between the two time points, and the significance was accepted as p &lt; 0.050. Significant differences with lower values during the consumption phase were found for absolute (mean difference ± SD: 88 ± 131 mL∙min−1; p = 0.021) and relative V˙O2peak (mean difference ± SD: 1 ± 2 mL∙min−1∙kg−1; p = 0.012). Higher values during the consumption phase were found for submaximal respiratory equivalents for V˙O2 (mean difference ± SD: −1.1 ± 1.7; p = 0.028) and V˙CO2 (mean difference ± SD: −0.9 ± 1.5; p = 0.032). No differences were found for all other parameters, including differences for endogenous sex hormones (p &gt; 0.050). The results of the current study suggest only marginal and physiologically insignificant differences in endurance-related parameters between oral contraceptive phases

Position statement regarding the current standing of exercise therapy in Austria (Positionspapier zur Situation der Trainingstherapie in Österreich)

In Austria, exercise therapy is an accredited profession that requires academic training on the university master’s level. However, exercise therapy is not listed in the service plans of health and medical insurance funds and is therefore not reimbursed as a health service for patients. This position paper aims to compile the scientific evidence of the efficacy and effectiveness of exercise therapy as a treatment component in medical care. It also informs about the skills and competencies that exercise therapists acquire during their university studies in sport science. Thus, the necessity to include exercise therapy as a health service for patients is argued. Additionally, legal parity for exercise therapists within the healthcare professions offering evidence-based treatment methods is advocated. Numerous studies confirm that exercise therapy clearly leads to improvements in musculoskeletal, internal, neurological, psychiatric, and psychosomatic diseases. Exercise therapy is a highly evidence-based, low-side-effect component of prevention, treatment, and rehabilitation measures for almost all chronic diseases. It has a positive impact on pathogenesis, symptoms, fitness, quality of life, morbidity, and mortality of affected patients. The five-year academic training in sport science for exercise therapists conveys medical, theoretical knowledge, and practical skills on training and exercise, communication-related, sports-, and movement-related skills, as well as a profound education in scientific methodology. Consequently, the integration of exercise as therapeutic treatment into the healthcare system is highly indicated from a medical, societal and economic perspective. A new legal framework offering self-employment regulations for exercise therapists is required

The comparison of maximal and endurance strength of quadriceps femori in trained and untrained elderly

The purpose of this study was to examine the differences in knee extensor maximal and endurance strength in elderly. Sixteen healthy elderly served as subjects, eight of them trained , age 61.0±8.9 yrs; height, 170.6±6.8 cm; weight, 71.8±11.7 kg [mean ± standard deviation] and eight untrained 61.4±8.1 yrs, height 174.6±7.4 cm; weight 83.9 ±14.2 kg. Maximal strength in single leg extension exercise was measured unilaterally with the dominant leg until the subjects reached their 1 Repetition Maximum (RM) covering the full Range of Motion (ROM). Muscular endurance was obtained with a load of 75% of 1-RM for 3 consecutive sets, with 2 min rest periods till failure. Load at 1 RM was lower in absolute terms in untrained, but not significant, while the relative 1-RM test was significantly lower in untrained subjects (0.20 vs. 0.25 kg load/kg body weight) (p<0.05). The number of repetitions and amount of weight lifted performed of all 3 sets was higher in trained subjects, but not significant. In the trained group both repetitions and the load managed in the third set was significant lower compared with the first two sets. The result that maximal force output is more affected compared to muscular endurance in these subjects might be due to the habitual use of quadriceps femoris muscles during activity of daily living in both trained and untrained elderly

The Enjoyability of Physical Exercise: Exergames and Virtual Reality as New Ways to Boost Psychological and Psychosocial Health in Astronauts. A Prospective and Perspective View

On Earth, physical activity plays a tremendous role to preserve and improve the physical, psychological, and social well-being of people. The enjoyability, the appreciation, and the variability of the exercises are fundamental factors for the production of lifestyle benefits. Currently, exercise countermeasures for astronauts during long-duration missions focus more on the physiological side, frequently overlooking the relevant psychosocial one. Exergames are a form of physical activity that have taken hold in the last decades on Earth and has been widely accepted as a more enjoyable and engaging rehabilitation, reconditioning, and training tool compared to the previous conventional ones. After a review of the current needs of astronauts and of the positive effects of exergames on people on Earth, we suggest that exergaming should be implemented in space missions to improve physical, psychological, and social well-being of astronauts. We also propose practical methods on how exergames can be effectively implemented

A Video-Based Tactical Task Does Not Elicit Mental Fatigue and Does Not Impair Soccer Performance in a Subsequent Small-Sided Game

Mental fatigue can impair physical, technical, and tactical performance in sports. Since most previous research used general cognitive tasks to elicit mental fatigue, the aim of this study was to investigate whether a more sport-specific task could induce the effects of mental fatigue and impair the subsequent physical and technical performance in a soccer small-sided game. Ten soccer players performed two small-sided games on two different days in a crossover design. Before each small-sided game, they performed a video-based tactical task (30 min) and a control task (documentary watching, 30 min) in a randomized and counterbalanced order. Mental effort was measured through a visual analog scale after the tactical and control tasks. Subjective ratings of perceived exertion were assessed through the RPE questionnaire after the end of the SSG. Physical performance was assessed during the SSG through GPS technology. Results showed no differences (p &gt; 0.05) in physical performance between the two conditions. None of the technical variables were negatively affected by the video-based tactical condition, with the number of total passes (p = 0.003; ES = 0.72 medium) and successful passes (p = 0.003; ES = 0.82 large) results even improved by the video-based tactical task. The mental effort required by the video-tactical task was significantly higher than the control task (p = 0.002; ES = 2.09 huge). However, overall RPE did not differ between conditions. The video-based tactical task did not elicit mental fatigue and did not impair subsequent physical and technical performance. The higher ecological validity of the task and the higher motivation of the participants might have contributed to the results

Belastungs Beanspruchungsprofil im Fussball aus physiologischer Sicht

Contains fulltext : mmubn000001_215791673.pdf (publisher's version ) (Open Access)Promotor : K. WellensXV, 396 p