The effect of repeated periods of speed endurance training on performance, running economy, and muscle adaptations

Skovgaard, Casper; Almquist, Nicki Winfield; Bangsbo, Jens

doi:10.1111/sms.12916

Cited by 16 publications

(29 citation statements)

References 31 publications

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“…The timing of muscle sampling in the present study (3 hours after exercise) might have affected the disclosed changes in NHE1, as HIE‐induced changes in mRNA tend to peak 24‐48 hours after exercise whereas protein content transiently seem to decrease 44 . The decreased expression of NHE1 in the current study and the unchanged protein abundancy in response to HIT in a previous study, 25 however, leaves the importance of NHE1 unequivocal. As for PDK4, LI led to a near‐significant increase in expression compared to SI, with the lack of significance potentially being related to the low statistical resolution of the study.…”

Section: Discussionmentioning

confidence: 54%

“…Also, SI may acutely lead to increased mRNA expression of ion‐handling proteins, 18 which may in turn be important for delaying fatigue during HIE around VO 2max 20,24 . While this perspective has gained less attention in previous studies of HIT, content of ion‐transporting proteins seem to increase after interventions of repeated sprint training in well‐trained subjects 25 . Finally, HIE may acutely increase protein synthesis in muscle fibers, potentially orchestrated through regulation of signaling factors such as PGC‐1α4, IGF1, and myostatin 26 .…”

Section: Introductionmentioning

confidence: 99%

“…20,24 While this perspective has gained less attention in previous studies of HIT, content of ion-transporting proteins seem to increase after interventions of repeated sprint training in well-trained subjects. 25 Finally, HIE may acutely increase protein synthesis in muscle fibers, potentially orchestrated through regulation of signaling factors such as PGC-1α4, IGF1, and myostatin. 26 Overall, few studies have investigated the effects of HIT on muscular adaptations in elite cyclists, likely due to skepticism connected to muscle biopsy sampling.…”

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confidence: 99%

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Systemic and muscular responses to effort‐matched short intervals and long intervals in elite cyclists

Almquist

Nygaard

Vegge

et al. 2020

Scandinavian Med Sci Sports

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The purpose of this study was to compare the acute effects of time‐ and effort‐matched high‐intensity intervals on physiological, endocrine, and skeletal muscle molecular variables in elite cyclists. Eight elite cyclists performed short intervals (SI: 30‐seconds) and long intervals (LI: 5‐minutes) with work:recovery ratio 2:1, using a randomized crossover design. SI was associated with 14% ± 3% higher mean power output (SI; 421 ± 27 vs LI; 371 ± 22 W), and longer working time above 90% of maximal oxygen uptake (VO2max, 54% ± 76%) and 90% peak heart rate (HRpeak, 153% ± 148%) than LI (all P < .05), despite similar degrees of perceived exertion, blood lactate levels and muscle activation measured using EMG root mean square (EMG rms). In blood, SI was associated with more pronounced increases in testosterone and testosterone‐to‐sex hormone‐binding globulin (SHBG) ratios, as well as prolonged cortisol responses (P < .05). In skeletal muscle (m. Vastus lateralis), SI and LI led to similar changes in mRNA abundance for a range of transcripts, with the exception of NHE1 mRNA, which decreased after SI (P < .05). Overall, SI was associated with more pronounced physiological and endocrine responses than LI in elite cyclists, suggesting that such training might lead to superior adaptations in elite cyclists.

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Section: Discussionmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Systemic and muscular responses to effort‐matched short intervals and long intervals in elite cyclists

Almquist

Nygaard

Vegge

et al. 2020

Scandinavian Med Sci Sports

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“…An interrelationship between PDK4 expression and glucose availability therefore seems likely. Furthermore, sprint exercise acutely increases several genes involved in fat metabolism, including PDK4, 27 and 6 weeks of sprint training leads to increased activity of enzymes involved in fat metabolism‐trained subjects 28 . It thus seems plausible to suggest that E&S increases the capacity of muscle tissue to metabolize fatty acids, despite continuous carbohydrate feeding during the exercise.…”

Section: Discussionmentioning

confidence: 99%

Effects of including sprints during prolonged cycling on hormonal and muscular responses and recovery in elite cyclists

Almquist

Ellefsen

Sandbakk

et al. 2020

Scandinavian Med Sci Sports

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This study investigated the acute effects of including 30‐second sprints during prolonged low‐intensity cycling on muscular and hormonal responses and recovery in elite cyclists. Twelve male cyclists (VO2max, 73.4 ± 4.0 mL/kg/min) completed a randomized crossover protocol, wherein 4 hours of cycling at 50% of VO2max were performed with and without inclusion of three sets of 3 × 30 seconds maximal sprints (E&S vs E, work‐matched). Muscle biopsies (m. vastus lateralis) and blood were sampled at Pre, immediately after (Post) and 3 hours after (3 h) finalizing sessions. E&S led to greater increases in mRNA levels compared with E for markers of fat metabolism (PDK4, Δ‐Log2 fold change between E&S and E ± 95%CI Post; 2.1 ± 0.9, Δ3h; 1.3 ± 0.7) and angiogenesis (VEGFA, Δ3h; 0.3 ± 0.3), and greater changes in markers of muscle protein turnover (myostatin, ΔPost; −1.4 ± 1.2, Δ3h; −1.3 ± 1.3; MuRF1, ΔPost; 1.5 ± 1.2, all P < .05). E&S showed decreased mRNA levels for markers of ion transport at 3h (Na+‐K+ α1; −0.6 ± 0.6, CLC1; −1.0 ± 0.8 and NHE1; −0.3 ± 0.2, all P < .05) and blunted responses for a marker of mitochondrial biogenesis (PGC‐1α, Post; −0.3 ± 0.3, 3h; −0.4 ± 0.3, P < .05) compared with E E&S and E showed similar endocrine responses, with exceptions of GH and SHBG, where E&S displayed lower responses at Post (GH; −4.1 ± 3.2 μg/L, SHBG; −2.2 ± 1.9 nmol/L, P < .05). Both E&S and E demonstrated complete recovery in isokinetic knee extension torque 24 hours after exercise. In conclusion, we demonstrate E&S to be an effective exercise protocol for elite cyclists, which potentially leads to beneficial adaptations in skeletal muscle without impairing muscle recovery 24 hours after exercise.

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“…6.2.1 Long-term and muscle memory. Muscle memory is achieved when information is embedded in a person to such an extent that minimal cognitive effort is required to access the information required to execute a task (Skovgaard et al, 2018). In other words, information has moved from short-term memory to long-term memory and then surpassed long-term memory and moved to muscle memory.…”

Section: Application Of Chunkingmentioning

confidence: 99%

Usability of the login authentication process: passphrases and passwords

Bhana

Flowerday

2021

ICS

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Purpose The average employee spends a total of 18.6 h every two months on password-related activities, including password retries and resets. The problem is caused by the user forgetting or mistyping the password (usually because of character switching). The source of this issue is that while a password containing combinations of lowercase characters, uppercase characters, digits and special characters (LUDS) offers a reasonable level of security, it is complex to type and/or memorise, which prolongs the user authentication process. This results in much time being spent for no benefit (as perceived by users), as the user authentication process is merely a prerequisite for whatever a user intends to accomplish. This study aims to address this issue, passphrases that exclude the LUDS guidelines are proposed. Design/methodology/approach To discover constructs that create security and to investigate usability concerns relating to the memory and typing issues concerning passphrases, this study was guided by three theories as follows: Shannon’s entropy theory was used to assess security, chunking theory to analyse memory issues and the keystroke level model to assess typing issues. These three constructs were then evaluated against passwords and passphrases to determine whether passphrases better address the security and usability issues related to text-based user authentication. A content analysis was performed to identify common password compositions currently used. A login assessment experiment was used to collect data on user authentication and user – system interaction with passwords and passphrases in line with the constructs that have an impact on user authentication issues related to security, memory and typing. User–system interaction data was collected from a purposeful sample size of 112 participants, logging in at least once a day for 10 days. An expert review, which comprised usability and security experts with specific years of industry and/or academic experience, was also used to validate results and conclusions. All the experts were given questions and content to ensure sufficient context was provided and relevant feedback was obtained. A pilot study involving 10 participants (experts in security and/or usability) was performed on the login assessment website and the content was given to the experts beforehand. Both the website and the expert review content was refined after feedback was received from the pilot study. Findings It was concluded that, overall, passphrases better support the user during the user authentication process in terms of security, memory issues and typing issues. Originality/value This research aims at promoting the use of a specific type of passphrase instead of complex passwords. Three core aspects need to be assessed in conjunction with each other (security, memorisation and typing) to determine whether user-friendly passphrases can support user authentication better than passwords.

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The effect of repeated periods of speed endurance training on performance, running economy, and muscle adaptations

Cited by 16 publications

References 31 publications

Systemic and muscular responses to effort‐matched short intervals and long intervals in elite cyclists

Systemic and muscular responses to effort‐matched short intervals and long intervals in elite cyclists

Effects of including sprints during prolonged cycling on hormonal and muscular responses and recovery in elite cyclists

Usability of the login authentication process: passphrases and passwords

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