Large Inter-individual Differences in Responses to a Block of High Intensity Aerobic Interval Training: a Case Series in National-level Cyclists and Triathletes

International Journal of Exercise Science 13(2): 480-487, 2020. The aim was to investigate individual responses on VO2maxand performance to a block of high intensity aerobic interval training (HIIT) in national-level endurance athletes. METHODS: National-level cyclists and triathletes (five men and two women, 31 ± 3.3 years, VO2max65.1 ± 3.3 ml·kg-1·min-1) conducted 14 HIIT sessions (4x4 min uphill running at 90-95% maximal heart rate) in nine days during preseason. VO2maxin running and cycling, lactate threshold (LT) in cycling, oxygen cost of cycling (CC), and a cycling time-trial (TT) were tested two days pre and seven days post intervention. Feasibility was determined using attendance rates, adherence (defined as completing all sessions), and reported adverse events. RESULTS: The results showed that adherence was 100% with 100% attendance rate. No adverse events were reported. TT (-75.6 ± 50.8 seconds, p\u3c 0.0001)but not VO2maxcycling (-0.2 ± 4.6 ml×kg-1×min-1, p= 0.53) or running (0.2 ± 1.2ml×kg-1×min-1, p= 0.85) was improved on group level. The individual responses varied from -8.2% to +14.5% change in VO2max, and -7.5% to +0.8% in TT. CONCLUSIONS: The large inter-individual differences in responses call for tailor-making HIIT blocks, mapping of biomarkers to avoid overtraining, and studying the effects of such blocks with longer follow-up than seven days

MAS and MANS Predicts repeated sprint ability in youth soccer players

International Journal of Exercise Science 16(6): 846-854, 2023. The study investigated the impact of maximal aerobic speed (MAS) and maximal anaerobic sprint (MANS) on repeated sprint ability (RSA) in soccer. Methods: 17 amateur-to semi-professional soccer players, age 19 (± 4) years, were tested for maximal oxygen consumption (VO2max), oxygen cost of running (Cr), RSA consisting of 15×20m sprint each divided by a 100 seconds dribble track, and 40-meter sprint performance. MAS was calculated as VO2max × Cr −1, and MANS was defined as the highest velocity in the 40-meter sprint. Results: There was a strong correlation between MAS and average 20-meter RSA velocity (r = 0.760; p \u3c 0.01), and between MAS and performance decrement (r = -0.648; p \u3c 0.01). The product of 0.5MAS + 0.5MANS exhibited the strongest correlation with RSA (r = 0.813; p \u3c 0.01). Conclusion: The combination of MAS and MANS strongly predicted RSA. High-intensity aerobic interval training (HIIT) and maximal strength training (MST) are recommended to improve MAS and MANS, and could thus lead to better RSA on the soccer field

Maximal Strength Training as a Therapeutic Approach in Long-Standing Anorexia Nervosa: A Case Study of a Woman With Osteopenia, Menstrual Dysfunction, and Compulsive Exercise

In persons with anorexia nervosa (AN), compulsive exercise and osteopenia are common symptoms. Although treatment of osteopenia besides weight regain is lacking, maximal strength training (MST) has been found to be effective in other populations. Such training has not been prescribed to those with AN due to uncertainty of tolerance. We therefore examined use of MST in a woman with long-standing AN, osteopenia, menstrual dysfunction, and compulsive exercise. The MST intervention consisted of four exercises: three sets of five repetitions maximum (RM), 3 times per week for 16 weeks. We examined muscle strength, bone mineral density (BMD), AN psychopathology, and compulsive exercise at baseline, posttest, and 6-month follow-up. Attendance rate was 100%. The subject improved muscle strength by 20% to 40%. BMD in lumbar spine improved by 4% to posttest, and by 8% from baseline to 6-month follow-up. The BMD T-scores shifted from values classified as osteopenic to normal values throughout the course of the intervention, despite continuance of menstrual dysfunction and lack of weight gain. No changes in AN psychopathology or levels of compulsive exercise were detected. Perceived psychological benefits including new bodily experiences were self-reported by the subject, emphasizing the importance of close follow-up by competent instructors.acceptedVersionNivå

Running and cycling economy in athletes; determining factors,training interventions and testing

Løps- og sykkeløkonomi hos idrettsutøvere; bestemmende faktorer, treningsintervensjoner og testing Arbeidet som denne doktorgradsavhandlingen er basert på ble utført ved Norges teknisk-naturvitenskapelige universitet og Høgskolen i Telemark. Det består av en rekke på fem eksperimentelle studier som har undersøkt bestemmende faktorer for løps- og sykkeløkonomi, treningsintervensjoner og testmetoder. De viktigste målemetodene i dette doktorgradsarbeidet var målinger av oksygenopptak under submaksimale og maksimale arbeidsbelastninger, under løp på tredemølle og sykling på testergometersykkel. Videre er det blant annet gjennomført laktatmålinger, målinger av maksimalstyrke og effekt i strekkapparat i underekstremitetene, kraftmålinger under løp og antropometriske målinger av idrettsutøverne. Det først studiet undersøkte effekten av melkesyre på oksygenkostnaden (CR) ved løp på laktatterskel. CR ble signifikant forverret når blodlaktatkonsentrasjonen ble økt fra 3 til 5 mm_L-1. Studie to undersøkte i hvilken grad en vanlig benyttet inkrementell protokoll for måling av oksygenopptak og CR påvirker reliabiliteten på disse målingene. Hastighet og relativ intensitet ble funnet å ikke påvirke CR på intensiteter mellom 60 og 90 % av maksimalt oksygenopptak. I studie tre og fem ble det undersøkt om maksimal styrketrening (knebøy) bedrer løps og sykkeløkonomi og tid til umattelse ved maksimal aerob hastighet. Både løps- og sykkeløkonomi ble signifikant forbedret etter 8 ukers maksimal styrketrening som et supplement til den vanlige utholdenhetstreningen. Disse forbedringene førte til signifikant lenger tid til utmattelse på maksimal aerob hastighet. Verken maksimalt oksygenopptak eller kroppsvekt ble forandret. Studie fire undersøkte sammenhenger mellom løps-karakteristika, maksimal styrke, antropometri og CR. Det ble funnet en signifikant negativ korrelasjon mellom summen av peak kraft, eksentrisk og konsentrisk, i hvert løpesteg og CR

Elevers prestasjonsutvikling - hvor mye betyr skolen og familien? Andre delrapport fra prosjektet 'Ressurser og resultater'

Ved å sammenlikne prestasjoner på to tidspunkter for de samme elevene, får vi mulighet til å undersøke betydningen av skolens bidrag til elevenes læringsutvikling (såkalte value-added analyser). Et viktig formål med rapporten er å undersøke skolens betydning for elevenes prestasjonsutvikling, men også andre forhold av betydning for elevenes prestasjonsutvikling blir analysert i denne rapporten, som er andre delrapport fra prosjektet 'Ressurser og resultater'. Hva betyr familie- og individkjennetegn for elevenes prestasjonsutvikling når vi tar hensyn til at elevene går på ulike skoler, og hvor mye betyr skolen når vi tar hensyn til at elevene har ulike ressurser i sitt hjem og nærmiljø

Relationships Between Maximal Aerobic Speed, Lactate Threshold, and Double Poling Velocity at Lactate Threshold in Cross-Country Skiers

Purpose: To investigate the relationships between maximal aerobic speed (MAS), lactate threshold in per cent of peak oxygen uptake (LT) and velocity at LT (LTv) in cross-country skiers. Secondly, we aimed to explore the fit of an equation previously used in cyclists and runners in a cohort of well-trained, competitive cross-country skiers for calculation of LTv. Thirdly, we aimed to investigate if a new LTv could still be calculated after a period of regular training only by providing a new MAS. Methods: Ninety-five competitive cross-country skiers (65 males and 30 females) were tested for maximal oxygen uptake (VO2max), peak oxygen uptake in double poling (DP-VO2peak), oxygen cost of double poling (CDP), LT, and LTv. Thirty-five skiers volunteered to be tested 3 months later to evaluate potential changes in LT and LTv. Results: Velocity at LT was mainly determined by MAS (r = 0.88, p < 0.01). LT did not show a significant impact on LTv. The product of MAS·LT precisely predicted LTv at baseline (r = 0.99, SEE = 2.4%), and by only measuring MAS, a new LTv could be accurately calculated (r = 0.92, SEE = 6.8%) 3 months later in a sub-set of the initial 95 skiers (n = 35). Conclusion: The results suggest that LT has minor impact on LTv in DP tested in a laboratory. LTv seemed to be predominantly determined by MAS, and we suggest to put more focus on MAS and less on LT and LTv in regular testing to evaluate aerobic performance capacity in DP

Relationships Between Maximal Aerobic Speed, Lactate Threshold, and Double Poling Velocity at Lactate Threshold in Cross-Country Skiers

Purpose: To investigate the relationships between maximal aerobic speed (MAS), lactate threshold in per cent of peak oxygen uptake (LT) and velocity at LT (LTv) in cross-country skiers. Secondly, we aimed to explore the fit of an equation previously used in cyclists and runners in a cohort of well-trained, competitive cross-country skiers for calculation of LTv. Thirdly, we aimed to investigate if a new LTv could still be calculated after a period of regular training only by providing a new MAS. Methods: Ninety-five competitive cross-country skiers (65 males and 30 females) were tested for maximal oxygen uptake (VO2max), peak oxygen uptake in double poling (DP-VO2peak), oxygen cost of double poling (CDP), LT, and LTv. Thirty-five skiers volunteered to be tested 3 months later to evaluate potential changes in LT and LTv. Results: Velocity at LT was mainly determined by MAS (r = 0.88, p < 0.01). LT did not show a significant impact on LTv. The product of MAS·LT precisely predicted LTv at baseline (r = 0.99, SEE = 2.4%), and by only measuring MAS, a new LTv could be accurately calculated (r = 0.92, SEE = 6.8%) 3 months later in a sub-set of the initial 95 skiers (n = 35). Conclusion: The results suggest that LT has minor impact on LTv in DP tested in a laboratory. LTv seemed to be predominantly determined by MAS, and we suggest to put more focus on MAS and less on LT and LTv in regular testing to evaluate aerobic performance capacity in DP

New flood frequency estimates for the largest river in Norway based on the combination of short and long time series

The Glomma River is the largest in Norway, with a catchment area of 154 450 km2. People living near the shores of this river are frequently exposed to destructive floods that impair local cities and communities. Unfortunately, design flood predictions are hampered by uncertainty since the standard flood records are much shorter than the requested return period and the climate is also expected to change in the coming decades. Here we combine systematic historical and paleo information in an effort to improve flood frequency analysis and better understand potential linkages to both climate and non-climatic forcing. Specifically, we (i) compile historical flood data from the existing literature, (ii) produce high-resolution X-ray fluorescence (XRF), magnetic susceptibility (MS), and computed tomography (CT) scanning data from a sediment core covering the last 10 300 years, and (iii) integrate these data sets in order to better estimate design floods and assess non-stationarities. Based on observations from Lake Flyginnsjøen, receiving sediments from Glomma only when it reaches a certain threshold, we can estimate flood frequency in a moving window of 50 years across millennia revealing that past flood frequency is non-stationary on different timescales. We observe that periods with increased flood activity (4000–2000 years ago and <1000 years ago) correspond broadly to intervals with lower than average summer temperatures and glacier growth, whereas intervals with higher than average summer temperatures and receding glaciers overlap with periods of reduced numbers of floods (10 000 to 4000 years ago and 2200 to 1000 years ago). The flood frequency shows significant non-stationarities within periods with increased flood activity, as was the case for the 18th century, including the 1789 CE (“Stor-Ofsen”) flood, the largest on record for the last 10 300 years at this site. Using the identified non-stationarities in the paleoflood record allowed us to estimate non-stationary design floods. In particular, we found that the design flood was 23 % higher during the 18th century than today and that long-term trends in flood variability are intrinsically linked to the availability of snow in late spring linking climate change to adjustments in flood frequency

Effects of individual changes in training distribution on maximal aerobic capacity in well-trained cross-country skiers: A follow-up study

The purpose of this study was to evaluate individual changes in training distribution and the subsequent effects on maximal oxygen uptake (VO2max). The participants were well-trained cross-country skiers who had performed a year with no substantial changes in training prior to this study. Six cross-country skiers, who were participants in a larger previous study, volunteered for a follow-up study. All skiers performed self-motivated changes in training distribution for a new preparation period in this follow-up, generally by more high-intensity training (HIT). All training characteristics were registered from training diaries. During the follow-up period, all skiers performed an incremental VO2max test in February 2020 and August 2020. Training were categorized into three different training periods; (1) February 2019 to February 2020 (P1) representing the training performed prior to the follow-up, (2) February 2020 to July 2020 (P2), and (3) July 2020 to August 2020 (P3). On average, the skiers increased their VO2max by 5.8 ± 5.0% (range: −1.8 to + 10.2%) during the follow-up study compared with the average VO2max during the preceding year. Total training volume increased on average by 10.0 and 25.7% in P2 and P3, respectively, compared with P1. The average volume of HIT was similar between P1 and P2 but increased 62.8% in P3. However, large individual differences in training changes were observed. In conclusion, the present study revealed that individual changes in training distribution generated an increased VO2max in four out of six already well-trained cross-country skiers. Reduced total training volume (three out of six) and increased (four out of six) HIT volume were the most marked changes

Factors Influencing Running Velocity at Lactate Threshold in Male and Female Runners at Different Levels of Performance

Background: The primary aim was to examine the relationship between lactate threshold (LT) expressed as percentage of maximal oxygen uptake (VO2max) and running velocity at LT (LTV). A secondary aim was to investigate to what extent VO2max, oxygen cost of running (CR), and maximal aerobic speed (MAS) determined LTV. A third aim was to investigate potential differences in LT and LTV between elite, national and recreational runners, as well as possible gender differences regarding VO2max, CR, LT, and LTV. Methods: Seventy-five competitive runners (37 males and 38 females) with an average VO2max of 63.0 ± 9.3 mL⋅kg–1⋅min–1, and an average LTV of 13.6 ± 2.3 km⋅h–1 were tested for VO2max, LT, LTV, MAS, and CR. Results: Lactate threshold did not correlate with LTV. With an r – value of 0.95 (p < 0.001) and a standard error of estimate of 4.0%, the product of MAS and individual LT determined 90% of LTV, outside a range of ±0.27 km⋅h–1. LTV increased with higher performance level. However, LT did not differ between elite, national and recreational runners. Female runners had 2.5% higher LT, 8% lower LTV, and 21% lower VO2max, but 9% better CR than male runners. Conclusion: Lactate threshold did not correlate with LTV. The product of MAS and LT correlated strongly with LTV. There were no differences between elite, national and recreational runners regarding LT, but female runners had higher LT than the male runners. Female runners at the same relative performance level had lower LTV and VO2max, but better CR than male runners