This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Scandinavian Journal of Medicine & Science in Sports, May 1, 2020
Soldiers participating in military field exercises or warfare often operate in a state of energy ... more Soldiers participating in military field exercises or warfare often operate in a state of energy deficit in a demanding environment, with little opportunity for rest, recovery, and nutritional intake. 1-4 The energy imbalance typically leads to a catabolic physiological state, accompanied by alterations in body composition, including loss of overall body mass, lean body mass (LBM), and fat mass. 1,2,5,6 The catabolic state is characterized by disturbances in endocrine functions, including reduced circulating levels of anabolic hormones such as testosterone (TESTO) and insulin-like growth factor 1 (IGF-1), and increased levels of catabolic hormones such as cortisol (COR), 3 which correlate well with observed losses in muscle mass
What are the new findings? ► Elite road cyclists have lower bone mineral density (BMD) compared w... more What are the new findings? ► Elite road cyclists have lower bone mineral density (BMD) compared with middle-distance and long-distance elite runners, despite performing lower limb heavy resistance training. Ten of 19 cyclists were classified with low BMD. ► Low BMD was evident in male and female cyclists and affected the lumbar spine and the femoral neck. ► Type of sport was the only independent variable associated with low BMD. How might it impact on clinical practice in the near future? ► Our finding of prevalent low BMD in elite cyclists extends previous research and raises the question of whether these athletes will be at risk of osteoporosis. ► The study also raises the issue of site-specific screening for osteoporosis in this population. AbsTrACT background Athletes who compete in non-weightbearing activities such as swimming and cycling are at risk of developing low bone mineral density (BMD). Athletes in long-distance running are at risk of low BMD. Objective (1) To evaluate the bone health in Norwegian male and female national elite road cyclists and middledistance and long-distance runners, and to identify cases of low BMD. (2) To identify possible risk factors associated with low BMD. Methods Twenty-one runners (11 females and 10 males) and 19 road cyclists (7 females and 12 males) were enrolled in this cross-sectional study. Dual-energy X-ray absorptiometry measurement of BMD in total body, femoral neck and lumbar spine was measured. Participants completed a questionnaire regarding training, injuries, calcium intake and health variables. results The cyclists had lower BMD for all measured sites compared with the runners (p≤0.05). Ten of 19 cyclists were classified as having low BMD according to American College of Sports Medicine criteria (Z-score ≤−1), despite reporting to train heavy resistance training on the lower extremities. Low BMD was site specific having occurred in the lumbar spine and the femoral neck and was not confined to females. Type of sport was the only factor significantly associated with low BMD. Conclusion National elite Norwegian road cyclists had lower BMD compared with runners, and a large proportion was classified as having low BMD, despite having performed heavy resistance training. Interventions to increase BMD in this population should be considered.
International Journal of Sport Nutrition and Exercise Metabolism, Mar 1, 2018
In elite sport, where opponents are evenly matched, small factors can determine the outcome of sp... more In elite sport, where opponents are evenly matched, small factors can determine the outcome of sporting contests. Not all athletes know the value of making wise nutrition choices, but anything that might give a competitive edge, including dietary supplements, can seem attractive. Between 40% and 100% of athletes typically use supplements, depending on the type of sport, level of competition, and the definition of supplements. However, unless the athlete has a nutrient deficiency, supplementation may not improve performance and may have a detrimental effect on both performance and health. Dietary supplements are classified as a subcategory of food, so manufacturers are not required to provide evidence of product safety and efficacy, nor obtain approval from regulatory bodies before marketing supplements. This creates the potential for health risks, and serious adverse effects have been reported from the use of some dietary supplements. Athletes who compete in sports under an anti-doping code must also realize that supplement use exposes them to a risk of ingesting banned substances or precursors of prohibited substances. Government systems of regulations do not include specific laboratory testing for banned substances according to the WADA list, so a separate regulatory framework to evaluate supplements for their risk of provoking a failed doping test is needed. In the highperformance culture typical of elite sport, athletes may use supplements regardless of possible risks. A discussion around medical, physiological, cultural, and ethical questions may be warranted to ensure that the athlete has the information needed to make an informed choice.
Current Opinion in Endocrine and Metabolic Research, Dec 1, 2019
Abstract There has been a remarkable rise in the popularity of herbal and botanical supplements t... more Abstract There has been a remarkable rise in the popularity of herbal and botanical supplements the last decade, owing to increased mindfulness toward health and well-being. However, several challenges such as contamination, undefined ingredients, and variable content of biologically active substances are of great concern for athletes who are tested regularly for banned substances. Athletes will unfortunately continue to be at risk of adverse events until authorities see the need for changing the rules and guidelines on how these products are regulated. In the meantime, there are several steps that can be taken to reduce the risk, including improved education of medical staff, coaches, and athletes; a greater awareness among consumers and the use of third-party–certified products.
Background: To detect longitudinal changes of resting metabolic rate (RMR) resulting from the eff... more Background: To detect longitudinal changes of resting metabolic rate (RMR) resulting from the effects of energetic stress, reliable RMR measurements are crucial. The Vyntus CPX is a new automated indirect calorimetry system for which RMR reliability has not been determined. Additionally, its agreement with common predictive RMR formulas is unknown. Aim: To determine the within and between-day reliability of RMR measurements using the Vyntus CPX system and its agreement with predictive RMR formulas. Methods: Young (31 ± 7 years) healthy participants (n = 26, 12 females, 14 males) completed three measurements of RMR, two consecutive measures on the same day, one the day before/after, all under standardised conditions. Reliability was assessed with pairwise comparisons of between-day at the same time (BDST), within day consecutive measurements (WDCM) and between-day different time (BDDT), for parameters of reliability (mean change (MC), intraclass correlation (ICC) and typical error of measurement (TEM)). Measured RMR values (kcal/day) were compared against predictive values of 4 common formulas. Results: Parameters of reliability (mean, (95% confidence interval)) were: -BDST: MC, 0.2(-2.3—2.7)% (p = 0.67); ICC, 0.92(0.84—0.97); TEM, 4.5(3.5—6.2)%. -WDCM: MC, −2.5(-6.2—1.3)% (p = 0.21); ICC, 0.88(0.74—0.88); TEM, 7.0(5.4—9.8)%. -BDDT: MC, −1.5(-4.8—1.9)% (p = 0.57); ICC, 0.90(0.76—0.95); TEM, 6.1(4.8—8.5)%. RMRratios (measured/predicted) were: 1.04 ± 0.14 (Nelson, p = 0.13), 1.03 ± 0.10 (Mifflin, p = 0.21), 0.98 ± 0.09 (Harris-benedict, p = 0.30), 0.95 ± 0.11 (Cunningham1980, p = 0.01), 1.00 ± 0.12 (Cunningham1991, p = 0.90) and 0.96 ± 0.13 (DXA, p = 0.03). Conclusions: The Vyntus CPX is reliable and measured RMR values agreed with four predictive formulas but are lower than Cunningham1980 and DXA RMR estimates for this population.
International Journal of Sport Nutrition and Exercise Metabolism, 2023
Dual energy x-ray absorptiometry (DXA) is a popular technique used to quantify physique in athlet... more Dual energy x-ray absorptiometry (DXA) is a popular technique used to quantify physique in athletic populations. Due to biological variation, DXA precision error (PE) may be higher than desired. Adherence to standardised presentation for testing has shown improvement in consecutive-day PE. However, the impact of short-term diet and physical activity standardisation prior to testing has not been explored. This warrants investigation, given the process may reduce variance in total body water and muscle solute, both of which can have high daily flux amongst athletes. Twenty (male n = 10, female n = 10) recreationally active individuals (age: 30.7±7.5 yrs; stature: 176.4±9.1 cm; mass: 74.6±14.3 kg) underwent three DXA scans; two consecutive scans on one day, and a third either the day before or after. In addition to adhering to standardised presentation for testing, subjects recorded all food/fluid intake plus activity undertaken in the 24 hours prior to the first DXA scan and replicated this the following 24 hours. International Society of Clinical Densitometry recommended techniques were used to calculate same-day and consecutive-day PE. There was no significant difference in PE of whole-body fat mass (479 vs. 626 g) and lean mass (634 vs. 734 g) between same-day and consecutive-day assessments. Same-day and consecutive-day PE of whole-body fat mass and lean mass were less than the smallest effect size of interest. Inclusion of 24 hours standardisation of diet and physical activity has the potential to reduce biological error further but this needs to be verified with follow-up investigation.
International Journal of Sport Nutrition and Exercise Metabolism, Jul 1, 2023
Background: Bioelectrical impedance analysis (BIA) is a popular technique which can be used to tr... more Background: Bioelectrical impedance analysis (BIA) is a popular technique which can be used to track longitudinal changes in body composition. However, precision of the technique has been questioned, especially among athletic populations where small but meaningful changes are often observed. Guidelines exist which attempt to optimize precision of the technique but fail to account for potentially important variables. Standardization of dietary intake and physical activity in the 24 hr prior to assessment has been proposed as an approach to minimizing the error of impedance-derived estimates of body composition. Methods: Eighteen recreational athletes, male (n = 10) and female (n = 8), underwent two consecutive BIA tests to quantify within-day error, and a third test (the day before or after) to quantify between-day error. All food and fluid intake plus physical activity from the 24 hr prior to the first BIA scan was replicated during the following 24 hr. Precision error was calculated as the root mean square standard deviation, percentage coefficient of variation, and least significant change. Results: There were no significant differences in precision error of within- and between-day fat-free mass, fat mass, and total body water. Differences in precision error of fat-free mass and total body water, but not fat mass, were less than the smallest effect size of interest. Conclusion: The 24-hr standardization of dietary intake and physical activity may be an effective approach to minimizing precision error associated with BIA. However, further research to confirm the validity of this protocol compared to nonstandardized or randomized intake is warranted.
Objective: Elderly muscle seems less sensitive to the anabolic stimulus of a meal. Changes in blo... more Objective: Elderly muscle seems less sensitive to the anabolic stimulus of a meal. Changes in blood concentrations of leucine are suggested as one important trigger of the anabolic response in muscle. The aim of this study was to investigate whether native whey protein, containing high amounts of leucine, may be a more potent stimulator of muscle protein synthesis (MPS) in elderly than regular whey protein (WPC-80) or milk. Design: Randomized controlled partial crossover. Setting: Norwegian School of Sport Sciences. Participants: 21 healthy elderly men and women (≥70 years). Intervention: Participants received either 20 g of WPC-80 and native whey (n = 11) on separate days in a crossover design, or milk (n = 10). Supplements were ingested immediately and two hours after a bout of lower body heavy-load resistance exercise. Measurements: Blood samples and muscle biopsies were collected to measure blood concentrations of amino acids by gas-chromatography mass spectrometry (GCMS), phosphorylation of p70S6K, 4E-BP1 and eEF-2 by immunoblotting and mixed muscle fractional synthetic rate (FSR) by use of [2H5]phenylalanine-infusion, GCMS and isotope-ratio mass spectrometry. Results: Native whey increased blood leucine concentrations more than WPC-80 (P < 0.05), but not p70S6K phosphorylation or mixed muscle FSR. Both whey supplements increased blood leucine concentrations (P < 0.01) and P70S6K phosphorylation more than milk (P = 0.014). Native whey reached higher mixed muscle FSR values than milk (P = 0.026) 1-3h after exercise. Conclusions: Despite greater increases in blood leucine concentrations than WPC-80 and milk, native whey was only superior to milk concerning increases in MPS and phosphorylation of P70S6K during a 5-hour post-exercise period in elderly individuals.
Objective: We aimed to assess the responsiveness of monitoring measures on cumulative training fr... more Objective: We aimed to assess the responsiveness of monitoring measures on cumulative training from the previous 1 up to 7 days in elite triathletes. Methods: Six male well-trained triathletes (31.8 ± 6.8 yrs, VO2max 70.5 ± 4.0 ml/kg/min) participated in a 9 weeks observational study during the pre-competition training period. Training load and time spent in different training intensity zones, morning measures of objective monitoring variables including resting heart rate, heart rate variability (HRV) and sleep duration and subjective monitoring variables including subjectively felt daily condition, energy level, willingness to train, muscle soreness, general stress, general fatigue and quality of sleep were assessed daily. Training data were retrospectively correlated with objective and subjective measures Results: On a group level, higher cumulative training time spent in high-intensity running but not swimming or cycling lead to moderate increase in muscle soreness (R=0.344 for 5-days cumulative high-intensity running, p=0.043), small increase in subjectively felt general stress (R=0.168 for 4-days. Cumulative high-intensity training time (cHITT), p=0.043 and R=0.221 for 6-days cHITT, p=0.043), a small decrease in daily condition (R=-0.113 for 7-days cHIIT, p=0.043) and willingness to train (R=-0.169 for 7-days cHIIT, p=0.043) but did not affect any objective monitoring variables.There were remarkable individual differences in correlations between cumulative training load, time spent in different training intensity zones and objective and subjective variables Conclusion: Since the responsiveness of objective and subjective monitoring parameters to training was very individual, not only training loads but also the selection of objective and subjective measures should be individualized for monitoring triathletes.
International Journal of Sport Nutrition and Exercise Metabolism, Nov 1, 2021
The syndrome of Relative Energy Deficiency in Sport (RED-S) includes wide-ranging effects on phys... more The syndrome of Relative Energy Deficiency in Sport (RED-S) includes wide-ranging effects on physiological and psychological functioning, performance, and general health. However, REDS is understudied among male athletes at the highest performance levels. This cross-sectional study aimed to investigate surrogate REDS markers prevalence in Norwegian male Olympic-level athletes. Athletes (N=44) aged 24.7±3.8 years, body mass 81.3±15.9kg, body fat 13.7±5.8%, and training volume 76.1±22.9 hours/month, were included. Assessed parameters included resting metabolic rate (RMR), body composition, and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) and venous blood variables (testosterone, free triiodothyronine (fT3), cortisol and lipids). Seven athletes (16%) grouped by the presence of low RMR (RMRratio <0.90) (0.81±0.07 vs. 1.04±0.09, p<0.001, effect size 2.6), also showed lower testosterone (12.9±5.3 vs. 19.0±5.3 nmol•l-1 , p=0.020) than in normal RMR group. In low RMRratio individuals, prevalence of other REDS markers (-subclinical-low testosterone, low fT3, high cortisol and elevated LDL) was (N/number of markers): 2/0, 2/1, 2/2, 1/3. Low BMD (z-score<-1) was found in 16% of the athletes, all with normal RMR. Subclinical low testosterone and fT3 levels were found in nine (25%) and two (5%) athletes, respectively. Subclinical high cortisol was found in 23% of athletes while 34% had elevated LDL cholesterol levels. Seven of twelve athletes with 2 or more REDS markers had normal RMR. In conclusion, this study found that multiple REDS markers also exist in male Olympic-level athletes. This highlights the importance of regular screening of male elite athletes, to ensure early detection and treatment of REDS .
Frontiers in sports and active living, May 3, 2022
Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performan... more Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performance consequences of low energy availability (LEA) and is common among female endurance athletes. Various underlying causes of LEA have been reported, including disordered eating behavior (DE), but studies investigating the association with exercise addiction and food intolerances are lacking. Therefore, the aim of this crosssectional study was to investigate the association between DE, exercise addiction and food intolerances in athletes at risk of LEA compared to those with low risk. Female endurance athletes, 18-35 years, training ≥5 times/week were recruited in Norway, Sweden, Ireland, and Germany. Participants completed an online-survey comprising the LEA in Females Questionnaire (LEAF-Q), Exercise Addiction Inventory (EAI), Eating Disorder Examination Questionnaire (EDE-Q), and questions regarding food intolerances. Of the 202 participants who met the inclusion criteria and completed the online survey, 65% were at risk of LEA, 23% were at risk of exercise addiction, and 21% had DE. Athletes at risk of LEA had higher EDE-Q and EAI scores compared to athletes with low risk. EAI score remained higher in athletes with risk of LEA after excluding athletes with DE. Athletes at risk of LEA did not report more food intolerances (17 vs. 10%, P = 0.198), but were more frequently reported by athletes with DE (28 vs. 11%, P = 0.004). In conclusion, these athletes had a high risk of LEA, exercise addiction, and DE. Exercise addiction should be considered as an additional risk factor in the prevention, early detection, and targeted treatment of REDS among female endurance athletes.
Female endurance athletes are considered a high-risk group for developing Relative Energy Deficie... more Female endurance athletes are considered a high-risk group for developing Relative Energy Deficiency in Sport (REDs). Due to the lack of educational and behavioral intervention studies, targeting and evaluating the effects of the practical daily management of REDs, we developed the Food and nUtrition for Endurance athletes—a Learning (FUEL) program, consisting of 16 weekly online lectures and individual athlete-centered nutrition counseling every other week. We recruited female endurance athletes from Norway (n = 60), Sweden (n = 84), Ireland (n = 17), and Germany (n = 47). Fifty athletes with symptoms of REDs and with low risk of eating disorders, with no use of hormonal contraceptives and no chronic diseases, were allocated to either the FUEL intervention (n = 32) (FUEL) or a 16-week control period (n = 18) (CON). All but one completed FUEL, while 15 completed CON. We found strong evidence for improvements in sports nutrition knowledge, assessed via interviews, and moderate to str...
Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performan... more Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performance consequences of low energy availability (LEA) and is common among female endurance athletes. Various underlying causes of LEA have been reported, including disordered eating behavior (DE), but studies investigating the association with exercise addiction and food intolerances are lacking. Therefore, the aim of this cross-sectional study was to investigate the association between DE, exercise addiction and food intolerances in athletes at risk of LEA compared to those with low risk. Female endurance athletes, 18–35 years, training ≥5 times/week were recruited in Norway, Sweden, Ireland, and Germany. Participants completed an online-survey comprising the LEA in Females Questionnaire (LEAF-Q), Exercise Addiction Inventory (EAI), Eating Disorder Examination Questionnaire (EDE-Q), and questions regarding food intolerances. Of the 202 participants who met the inclusion criteria and complete...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Scandinavian Journal of Medicine & Science in Sports, May 1, 2020
Soldiers participating in military field exercises or warfare often operate in a state of energy ... more Soldiers participating in military field exercises or warfare often operate in a state of energy deficit in a demanding environment, with little opportunity for rest, recovery, and nutritional intake. 1-4 The energy imbalance typically leads to a catabolic physiological state, accompanied by alterations in body composition, including loss of overall body mass, lean body mass (LBM), and fat mass. 1,2,5,6 The catabolic state is characterized by disturbances in endocrine functions, including reduced circulating levels of anabolic hormones such as testosterone (TESTO) and insulin-like growth factor 1 (IGF-1), and increased levels of catabolic hormones such as cortisol (COR), 3 which correlate well with observed losses in muscle mass
What are the new findings? ► Elite road cyclists have lower bone mineral density (BMD) compared w... more What are the new findings? ► Elite road cyclists have lower bone mineral density (BMD) compared with middle-distance and long-distance elite runners, despite performing lower limb heavy resistance training. Ten of 19 cyclists were classified with low BMD. ► Low BMD was evident in male and female cyclists and affected the lumbar spine and the femoral neck. ► Type of sport was the only independent variable associated with low BMD. How might it impact on clinical practice in the near future? ► Our finding of prevalent low BMD in elite cyclists extends previous research and raises the question of whether these athletes will be at risk of osteoporosis. ► The study also raises the issue of site-specific screening for osteoporosis in this population. AbsTrACT background Athletes who compete in non-weightbearing activities such as swimming and cycling are at risk of developing low bone mineral density (BMD). Athletes in long-distance running are at risk of low BMD. Objective (1) To evaluate the bone health in Norwegian male and female national elite road cyclists and middledistance and long-distance runners, and to identify cases of low BMD. (2) To identify possible risk factors associated with low BMD. Methods Twenty-one runners (11 females and 10 males) and 19 road cyclists (7 females and 12 males) were enrolled in this cross-sectional study. Dual-energy X-ray absorptiometry measurement of BMD in total body, femoral neck and lumbar spine was measured. Participants completed a questionnaire regarding training, injuries, calcium intake and health variables. results The cyclists had lower BMD for all measured sites compared with the runners (p≤0.05). Ten of 19 cyclists were classified as having low BMD according to American College of Sports Medicine criteria (Z-score ≤−1), despite reporting to train heavy resistance training on the lower extremities. Low BMD was site specific having occurred in the lumbar spine and the femoral neck and was not confined to females. Type of sport was the only factor significantly associated with low BMD. Conclusion National elite Norwegian road cyclists had lower BMD compared with runners, and a large proportion was classified as having low BMD, despite having performed heavy resistance training. Interventions to increase BMD in this population should be considered.
International Journal of Sport Nutrition and Exercise Metabolism, Mar 1, 2018
In elite sport, where opponents are evenly matched, small factors can determine the outcome of sp... more In elite sport, where opponents are evenly matched, small factors can determine the outcome of sporting contests. Not all athletes know the value of making wise nutrition choices, but anything that might give a competitive edge, including dietary supplements, can seem attractive. Between 40% and 100% of athletes typically use supplements, depending on the type of sport, level of competition, and the definition of supplements. However, unless the athlete has a nutrient deficiency, supplementation may not improve performance and may have a detrimental effect on both performance and health. Dietary supplements are classified as a subcategory of food, so manufacturers are not required to provide evidence of product safety and efficacy, nor obtain approval from regulatory bodies before marketing supplements. This creates the potential for health risks, and serious adverse effects have been reported from the use of some dietary supplements. Athletes who compete in sports under an anti-doping code must also realize that supplement use exposes them to a risk of ingesting banned substances or precursors of prohibited substances. Government systems of regulations do not include specific laboratory testing for banned substances according to the WADA list, so a separate regulatory framework to evaluate supplements for their risk of provoking a failed doping test is needed. In the highperformance culture typical of elite sport, athletes may use supplements regardless of possible risks. A discussion around medical, physiological, cultural, and ethical questions may be warranted to ensure that the athlete has the information needed to make an informed choice.
Current Opinion in Endocrine and Metabolic Research, Dec 1, 2019
Abstract There has been a remarkable rise in the popularity of herbal and botanical supplements t... more Abstract There has been a remarkable rise in the popularity of herbal and botanical supplements the last decade, owing to increased mindfulness toward health and well-being. However, several challenges such as contamination, undefined ingredients, and variable content of biologically active substances are of great concern for athletes who are tested regularly for banned substances. Athletes will unfortunately continue to be at risk of adverse events until authorities see the need for changing the rules and guidelines on how these products are regulated. In the meantime, there are several steps that can be taken to reduce the risk, including improved education of medical staff, coaches, and athletes; a greater awareness among consumers and the use of third-party–certified products.
Background: To detect longitudinal changes of resting metabolic rate (RMR) resulting from the eff... more Background: To detect longitudinal changes of resting metabolic rate (RMR) resulting from the effects of energetic stress, reliable RMR measurements are crucial. The Vyntus CPX is a new automated indirect calorimetry system for which RMR reliability has not been determined. Additionally, its agreement with common predictive RMR formulas is unknown. Aim: To determine the within and between-day reliability of RMR measurements using the Vyntus CPX system and its agreement with predictive RMR formulas. Methods: Young (31 ± 7 years) healthy participants (n = 26, 12 females, 14 males) completed three measurements of RMR, two consecutive measures on the same day, one the day before/after, all under standardised conditions. Reliability was assessed with pairwise comparisons of between-day at the same time (BDST), within day consecutive measurements (WDCM) and between-day different time (BDDT), for parameters of reliability (mean change (MC), intraclass correlation (ICC) and typical error of measurement (TEM)). Measured RMR values (kcal/day) were compared against predictive values of 4 common formulas. Results: Parameters of reliability (mean, (95% confidence interval)) were: -BDST: MC, 0.2(-2.3—2.7)% (p = 0.67); ICC, 0.92(0.84—0.97); TEM, 4.5(3.5—6.2)%. -WDCM: MC, −2.5(-6.2—1.3)% (p = 0.21); ICC, 0.88(0.74—0.88); TEM, 7.0(5.4—9.8)%. -BDDT: MC, −1.5(-4.8—1.9)% (p = 0.57); ICC, 0.90(0.76—0.95); TEM, 6.1(4.8—8.5)%. RMRratios (measured/predicted) were: 1.04 ± 0.14 (Nelson, p = 0.13), 1.03 ± 0.10 (Mifflin, p = 0.21), 0.98 ± 0.09 (Harris-benedict, p = 0.30), 0.95 ± 0.11 (Cunningham1980, p = 0.01), 1.00 ± 0.12 (Cunningham1991, p = 0.90) and 0.96 ± 0.13 (DXA, p = 0.03). Conclusions: The Vyntus CPX is reliable and measured RMR values agreed with four predictive formulas but are lower than Cunningham1980 and DXA RMR estimates for this population.
International Journal of Sport Nutrition and Exercise Metabolism, 2023
Dual energy x-ray absorptiometry (DXA) is a popular technique used to quantify physique in athlet... more Dual energy x-ray absorptiometry (DXA) is a popular technique used to quantify physique in athletic populations. Due to biological variation, DXA precision error (PE) may be higher than desired. Adherence to standardised presentation for testing has shown improvement in consecutive-day PE. However, the impact of short-term diet and physical activity standardisation prior to testing has not been explored. This warrants investigation, given the process may reduce variance in total body water and muscle solute, both of which can have high daily flux amongst athletes. Twenty (male n = 10, female n = 10) recreationally active individuals (age: 30.7±7.5 yrs; stature: 176.4±9.1 cm; mass: 74.6±14.3 kg) underwent three DXA scans; two consecutive scans on one day, and a third either the day before or after. In addition to adhering to standardised presentation for testing, subjects recorded all food/fluid intake plus activity undertaken in the 24 hours prior to the first DXA scan and replicated this the following 24 hours. International Society of Clinical Densitometry recommended techniques were used to calculate same-day and consecutive-day PE. There was no significant difference in PE of whole-body fat mass (479 vs. 626 g) and lean mass (634 vs. 734 g) between same-day and consecutive-day assessments. Same-day and consecutive-day PE of whole-body fat mass and lean mass were less than the smallest effect size of interest. Inclusion of 24 hours standardisation of diet and physical activity has the potential to reduce biological error further but this needs to be verified with follow-up investigation.
International Journal of Sport Nutrition and Exercise Metabolism, Jul 1, 2023
Background: Bioelectrical impedance analysis (BIA) is a popular technique which can be used to tr... more Background: Bioelectrical impedance analysis (BIA) is a popular technique which can be used to track longitudinal changes in body composition. However, precision of the technique has been questioned, especially among athletic populations where small but meaningful changes are often observed. Guidelines exist which attempt to optimize precision of the technique but fail to account for potentially important variables. Standardization of dietary intake and physical activity in the 24 hr prior to assessment has been proposed as an approach to minimizing the error of impedance-derived estimates of body composition. Methods: Eighteen recreational athletes, male (n = 10) and female (n = 8), underwent two consecutive BIA tests to quantify within-day error, and a third test (the day before or after) to quantify between-day error. All food and fluid intake plus physical activity from the 24 hr prior to the first BIA scan was replicated during the following 24 hr. Precision error was calculated as the root mean square standard deviation, percentage coefficient of variation, and least significant change. Results: There were no significant differences in precision error of within- and between-day fat-free mass, fat mass, and total body water. Differences in precision error of fat-free mass and total body water, but not fat mass, were less than the smallest effect size of interest. Conclusion: The 24-hr standardization of dietary intake and physical activity may be an effective approach to minimizing precision error associated with BIA. However, further research to confirm the validity of this protocol compared to nonstandardized or randomized intake is warranted.
Objective: Elderly muscle seems less sensitive to the anabolic stimulus of a meal. Changes in blo... more Objective: Elderly muscle seems less sensitive to the anabolic stimulus of a meal. Changes in blood concentrations of leucine are suggested as one important trigger of the anabolic response in muscle. The aim of this study was to investigate whether native whey protein, containing high amounts of leucine, may be a more potent stimulator of muscle protein synthesis (MPS) in elderly than regular whey protein (WPC-80) or milk. Design: Randomized controlled partial crossover. Setting: Norwegian School of Sport Sciences. Participants: 21 healthy elderly men and women (≥70 years). Intervention: Participants received either 20 g of WPC-80 and native whey (n = 11) on separate days in a crossover design, or milk (n = 10). Supplements were ingested immediately and two hours after a bout of lower body heavy-load resistance exercise. Measurements: Blood samples and muscle biopsies were collected to measure blood concentrations of amino acids by gas-chromatography mass spectrometry (GCMS), phosphorylation of p70S6K, 4E-BP1 and eEF-2 by immunoblotting and mixed muscle fractional synthetic rate (FSR) by use of [2H5]phenylalanine-infusion, GCMS and isotope-ratio mass spectrometry. Results: Native whey increased blood leucine concentrations more than WPC-80 (P < 0.05), but not p70S6K phosphorylation or mixed muscle FSR. Both whey supplements increased blood leucine concentrations (P < 0.01) and P70S6K phosphorylation more than milk (P = 0.014). Native whey reached higher mixed muscle FSR values than milk (P = 0.026) 1-3h after exercise. Conclusions: Despite greater increases in blood leucine concentrations than WPC-80 and milk, native whey was only superior to milk concerning increases in MPS and phosphorylation of P70S6K during a 5-hour post-exercise period in elderly individuals.
Objective: We aimed to assess the responsiveness of monitoring measures on cumulative training fr... more Objective: We aimed to assess the responsiveness of monitoring measures on cumulative training from the previous 1 up to 7 days in elite triathletes. Methods: Six male well-trained triathletes (31.8 ± 6.8 yrs, VO2max 70.5 ± 4.0 ml/kg/min) participated in a 9 weeks observational study during the pre-competition training period. Training load and time spent in different training intensity zones, morning measures of objective monitoring variables including resting heart rate, heart rate variability (HRV) and sleep duration and subjective monitoring variables including subjectively felt daily condition, energy level, willingness to train, muscle soreness, general stress, general fatigue and quality of sleep were assessed daily. Training data were retrospectively correlated with objective and subjective measures Results: On a group level, higher cumulative training time spent in high-intensity running but not swimming or cycling lead to moderate increase in muscle soreness (R=0.344 for 5-days cumulative high-intensity running, p=0.043), small increase in subjectively felt general stress (R=0.168 for 4-days. Cumulative high-intensity training time (cHITT), p=0.043 and R=0.221 for 6-days cHITT, p=0.043), a small decrease in daily condition (R=-0.113 for 7-days cHIIT, p=0.043) and willingness to train (R=-0.169 for 7-days cHIIT, p=0.043) but did not affect any objective monitoring variables.There were remarkable individual differences in correlations between cumulative training load, time spent in different training intensity zones and objective and subjective variables Conclusion: Since the responsiveness of objective and subjective monitoring parameters to training was very individual, not only training loads but also the selection of objective and subjective measures should be individualized for monitoring triathletes.
International Journal of Sport Nutrition and Exercise Metabolism, Nov 1, 2021
The syndrome of Relative Energy Deficiency in Sport (RED-S) includes wide-ranging effects on phys... more The syndrome of Relative Energy Deficiency in Sport (RED-S) includes wide-ranging effects on physiological and psychological functioning, performance, and general health. However, REDS is understudied among male athletes at the highest performance levels. This cross-sectional study aimed to investigate surrogate REDS markers prevalence in Norwegian male Olympic-level athletes. Athletes (N=44) aged 24.7±3.8 years, body mass 81.3±15.9kg, body fat 13.7±5.8%, and training volume 76.1±22.9 hours/month, were included. Assessed parameters included resting metabolic rate (RMR), body composition, and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) and venous blood variables (testosterone, free triiodothyronine (fT3), cortisol and lipids). Seven athletes (16%) grouped by the presence of low RMR (RMRratio <0.90) (0.81±0.07 vs. 1.04±0.09, p<0.001, effect size 2.6), also showed lower testosterone (12.9±5.3 vs. 19.0±5.3 nmol•l-1 , p=0.020) than in normal RMR group. In low RMRratio individuals, prevalence of other REDS markers (-subclinical-low testosterone, low fT3, high cortisol and elevated LDL) was (N/number of markers): 2/0, 2/1, 2/2, 1/3. Low BMD (z-score<-1) was found in 16% of the athletes, all with normal RMR. Subclinical low testosterone and fT3 levels were found in nine (25%) and two (5%) athletes, respectively. Subclinical high cortisol was found in 23% of athletes while 34% had elevated LDL cholesterol levels. Seven of twelve athletes with 2 or more REDS markers had normal RMR. In conclusion, this study found that multiple REDS markers also exist in male Olympic-level athletes. This highlights the importance of regular screening of male elite athletes, to ensure early detection and treatment of REDS .
Frontiers in sports and active living, May 3, 2022
Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performan... more Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performance consequences of low energy availability (LEA) and is common among female endurance athletes. Various underlying causes of LEA have been reported, including disordered eating behavior (DE), but studies investigating the association with exercise addiction and food intolerances are lacking. Therefore, the aim of this crosssectional study was to investigate the association between DE, exercise addiction and food intolerances in athletes at risk of LEA compared to those with low risk. Female endurance athletes, 18-35 years, training ≥5 times/week were recruited in Norway, Sweden, Ireland, and Germany. Participants completed an online-survey comprising the LEA in Females Questionnaire (LEAF-Q), Exercise Addiction Inventory (EAI), Eating Disorder Examination Questionnaire (EDE-Q), and questions regarding food intolerances. Of the 202 participants who met the inclusion criteria and completed the online survey, 65% were at risk of LEA, 23% were at risk of exercise addiction, and 21% had DE. Athletes at risk of LEA had higher EDE-Q and EAI scores compared to athletes with low risk. EAI score remained higher in athletes with risk of LEA after excluding athletes with DE. Athletes at risk of LEA did not report more food intolerances (17 vs. 10%, P = 0.198), but were more frequently reported by athletes with DE (28 vs. 11%, P = 0.004). In conclusion, these athletes had a high risk of LEA, exercise addiction, and DE. Exercise addiction should be considered as an additional risk factor in the prevention, early detection, and targeted treatment of REDS among female endurance athletes.
Female endurance athletes are considered a high-risk group for developing Relative Energy Deficie... more Female endurance athletes are considered a high-risk group for developing Relative Energy Deficiency in Sport (REDs). Due to the lack of educational and behavioral intervention studies, targeting and evaluating the effects of the practical daily management of REDs, we developed the Food and nUtrition for Endurance athletes—a Learning (FUEL) program, consisting of 16 weekly online lectures and individual athlete-centered nutrition counseling every other week. We recruited female endurance athletes from Norway (n = 60), Sweden (n = 84), Ireland (n = 17), and Germany (n = 47). Fifty athletes with symptoms of REDs and with low risk of eating disorders, with no use of hormonal contraceptives and no chronic diseases, were allocated to either the FUEL intervention (n = 32) (FUEL) or a 16-week control period (n = 18) (CON). All but one completed FUEL, while 15 completed CON. We found strong evidence for improvements in sports nutrition knowledge, assessed via interviews, and moderate to str...
Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performan... more Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performance consequences of low energy availability (LEA) and is common among female endurance athletes. Various underlying causes of LEA have been reported, including disordered eating behavior (DE), but studies investigating the association with exercise addiction and food intolerances are lacking. Therefore, the aim of this cross-sectional study was to investigate the association between DE, exercise addiction and food intolerances in athletes at risk of LEA compared to those with low risk. Female endurance athletes, 18–35 years, training ≥5 times/week were recruited in Norway, Sweden, Ireland, and Germany. Participants completed an online-survey comprising the LEA in Females Questionnaire (LEAF-Q), Exercise Addiction Inventory (EAI), Eating Disorder Examination Questionnaire (EDE-Q), and questions regarding food intolerances. Of the 202 participants who met the inclusion criteria and complete...
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