ABSTRACT
A non-exercise method equation using seismocardiography for estimating VÌO2peak (SCG VÌO2peak) has previously been validated in healthy subjects. However, the performance of the SCG VÌO2peak within a trained population is unknown, and the ability of the model to detect changes over time is not well elucidated. Forty-seven sub-elite football players were tested at the start of pre-season (SPS) and 36 players completed a test after eight weeks at the end of the pre-season (EPS). Testing included an SCG VÌO2peak estimation at rest and a graded cardiopulmonary exercise test (CPET) on a treadmill for determination of VÌO2peak. Agreement between SCG VÌO2peak and CPET VÌO2peak showed a large underestimation at SPS (bias ± 95% CI: -9.9 ± 1.8, 95% Limits of Agreement: 2.2 to -22.0 mL·min-1 kg-1). At EPS no interaction (p = 0.3590) but a main effect of time (p < 0.0001) and methods (p < 0.0001) was observed between SCG and CPET VÌO2peak. No correlation in VÌO2peak changes was observed between SCG and CPET (r = -20.0, p = 0.2484) but a fair agreement in classifying the correct directional change in VÌO2peak with the SCG method was found (Cohen's κ coefficient = 0.28 ± 0.25). Overall, the SCG VÌO2peak method lacks accuracy and despite being able to estimate group changes, it was incapable of detecting individual changes in VÌO2peak following a pre-season period in sub-elite football players. The SCG algorithm needs to be further adjusted and the accuracy and precision improved for the method to be applicable for use within a trained population.
Subject(s)
Exercise Test , Oxygen Consumption , Soccer , Humans , Exercise Test/methods , Soccer/physiology , Young Adult , Male , Oxygen Consumption/physiology , Adult , Athletes , AdolescentABSTRACT
PURPOSE: In Football, the high-intensity running bouts during matches are considered decisive. Interestingly, recent studies showed that peak fat oxidation rates (PFO) are higher in football players than other athletes. This study aimed to investigate whether PFO increases following a pre-season. Secondarily, and due to COVID-19, we investigated whether PFO is related to the physical performance in a subgroup of semi-professional male football players. METHODS: Before and after 8 weeks of pre-season training, 42 sub-elite male football players (18 semi-professionals and 24 non-professionals) had a dual-energy x-ray absorptiometry scan and performed a graded exercise test on a treadmill for the determination of PFO, the exercise intensity eliciting PFO (Fatmax) and peak oxygen uptake (VÌO2peak). Additionally, the semi-professional players performed a Yo-Yo Intermittent Recovery Test level 2 (YYIR2) before and after pre-season training to determine football-specific running performance. RESULTS: PFO increased by 11 ± 10% (mean ± 95% CI), p = 0.031, and VÌO2peak increased by 5 ± 1%, p < 0.001, whereas Fatmax was unchanged (+12 ± 9%, p = 0.057), following pre-season training. PFO increments were not associated with increments in VÌO2peak (Pearson's r2 = 0.00, p = 0.948) or fat-free mass (FFM) (r2 = 0.00, p = 0.969). Concomitantly, YYIR2 performance increased in the semi-professional players by 39 ± 17%, p < 0.001, which was associated with changes in VÌO2peak (r2 = 0.35, p = 0.034) but not PFO (r2 = 0.13, p = 0.244). CONCLUSIONS: PFO, VÌO2peak, and FFM increased following pre-season training in sub-elite football players. However, in a subgroup of semi-professional players, increments in PFO were not associated with improvements in YYIR2 performance nor with increments in VÌO2peak and FFM.
Subject(s)
Athletic Performance , Running , Soccer , Humans , Male , Exercise Test , Oxygen , SeasonsABSTRACT
INTRODUCTION: Liver fat (LF) and visceral adipose tissue (VAT) content decreases with training, however, this has mainly been investigated in sedentary obese or healthy participants. The aim of this study was to investigate the effects of repeated prolonged exercise on LF and VAT content in well-trained older men and to compare baseline LF and VAT content to recreationally active older men. METHOD: A group of five well-trained older men were tested before and after cycling a total distance of 2558 km in 16 consecutive days. VAT content and body composition was measured using DXA before a bicycle ergometer test was performed to determine maximal fat oxidation (MFO), maximal oxygen consumption ( VO 2 max $$ {\mathrm{VO}}_{2_{\mathrm{max}}} $$ ), and the relative intensity at which MFO occurred (Fatmax). LF content was measured on a separate day using MRI. For comparison of baseline values, a control group of eight healthy age- and BMI-matched recreationally active men were recruited. RESULTS: The well-trained older men had lower VAT (p = 0.02), and a tendency toward lower LF content (p = 0.06) compared with the control group. The intervention resulted in decreased LF content (p = 0.02), but VAT, fat mass, and lean mass remained unchanged. VO 2 max $$ {\mathrm{VO}}_{2_{\mathrm{max}}} $$ , MFO, and Fatmax were not affected by the intervention. CONCLUSION: The study found that repeated prolonged exercise reduced LF content, but VAT and VO 2 max $$ {\mathrm{VO}}_{2_{\mathrm{max}}} $$ remained unchanged. Aerobic capacity was aligned with lower LF and VAT in older active men.
Subject(s)
Exercise , Intra-Abdominal Fat , Male , Humans , Aged , Obesity/metabolism , Liver/diagnostic imaging , Exercise Test , Adipose Tissue/metabolism , Oxygen ConsumptionABSTRACT
BACKGROUND: The aim of this study was to investigate the effect of prolonged endurance exercise on adipose tissue inflammation markers and mitochondrial respiration in younger and older men. METHODS: "Young" (aged 30 years, n = 7) and "old" (aged 65 years, n = 7) trained men were exposed to an exercise intervention of 15 consecutive days biking 7 to 9 hours/day at 63% and 65% of maximal heart rate (young and old, respectively), going from Copenhagen, Denmark to Palermo, Italy. Adipose tissue was sampled from both the gluteal and abdominal depot before and after the intervention. Mitochondrial respiration was measured by high-resolution respirometry, and adipose inflammation was assessed by immunohistochemical staining of paraffin embedded sections. RESULTS: An increased number of CD163+ macrophages was observed in both the gluteal and abdominal depot (P < .01). In addition, an increased mitochondrial respiration was observed in the abdominal adipose tissue from men in the young group with complex I (CIp) stimulated respiration, complex I + II (CI+IIp) stimulated respiration and the capacity of the electron transport system (ETS) (P < .05), and in the older group an increase in CIp and CI+IIp stimulated respiration (P < .05) was found. CONCLUSION: Overall, we found a positive effect of prolonged endurance exercise on adipose tissue inflammation markers and mitochondrial respiration in both young and old trained men, and no sign of attenuated function in adipose tissue with age.
Subject(s)
Adipose Tissue , Respiration , Male , Humans , Aged , Exercise Therapy , Macrophages , InflammationABSTRACT
Cardiorespiratory fitness measured as ËVO2max is considered an important variable in the risk prediction of cardiovascular disease and all-cause mortality. Non-exercise ËVO2max prediction models are applicable, but lack accuracy. Here a model for the prediction of ËVO2max using seismocardiography (SCG) was investigated. 97 healthy participants (18-65 yrs., 51 females) underwent measurement of SCG at rest in the supine position combined with demographic data to predict ËVO2max before performing a graded exercise test (GET) on a cycle ergometer for determination of ËVO2max using pulmonary gas exchange measurements for comparison. Accuracy assessment revealed no significant difference between SCG and GET ËVO2max (mean±95% CI; 38.3±1.6 and 39.3±1.6 ml·min-1·kg-1, respectively. P=0.075). Further, a Pearson correlation of r=0.73, a standard error of estimate (SEE) of 5.9 ml·min-1·kg-1, and a coefficient of variation (CV) of 8±1% were found. The SCG ËVO2max showed higher accuracy, than the non-exercise model based on the FRIENDS study, when this was applied to the present population (bias=-3.7±1.3 ml·min-1·kg-1, p<0.0001. r=0.70. SEE=7.4 ml·min-1·kg-1, and CV=12±2%). The SCG ËVO2max prediction model is an accurate method for the determination of ËVO2max in a healthy adult population. However, further investigation on the validity and reliability of the SCG ËVO2max prediction model in different populations is needed for consideration of clinical applicability.
Subject(s)
Oxygen Consumption , Humans , Male , Female , Adolescent , Young Adult , Adult , Middle Aged , Aged , Heart Function Tests , Exercise TestABSTRACT
AIM & METHODS: Extreme endurance exercise provides a valuable research model for understanding the adaptive metabolic response of older and younger individuals to intense physical activity. Here, we compare a wide range of metabolic and physiologic parameters in two cohorts of seven trained men, age 30 ± 5 years or age 65 ± 6 years, before and after the participants travelled ≈3000 km by bicycle over 15 days. RESULTS: Over the 15-day exercise intervention, participants lost 2-3 kg fat mass with no significant change in body weight. VÌO2 max did not change in younger cyclists, but decreased (p = 0.06) in the older cohort. The resting plasma FFA concentration decreased markedly in both groups, and plasma glucose increased in the younger group. In the older cohort, plasma LDL-cholesterol and plasma triglyceride decreased. In skeletal muscle, fat transporters CD36 and FABPm remained unchanged. The glucose handling proteins GLUT4 and SNAP23 increased in both groups. Mitochondrial ROS production decreased in both groups, and ADP sensitivity increased in skeletal muscle in the older but not in the younger cohort. CONCLUSION: In summary, these data suggest that older but not younger individuals experience a negative adaptive response affecting cardiovascular function in response to extreme endurance exercise, while a positive response to the same exercise intervention is observed in peripheral tissues in younger and older men. The results also suggest that the adaptive thresholds differ in younger and old men, and this difference primarily affects central cardiovascular functions in older men after extreme endurance exercise.
Subject(s)
Exercise , Muscle, Skeletal , Adult , Aged , Body Weight , Exercise/physiology , Humans , Male , Middle Aged , Muscle, Skeletal/metabolism , Physical Endurance/physiology , Rest/physiology , Triglycerides/metabolismABSTRACT
INTRODUCTION: The scientific outcome of Health Science PhD theses has been questioned by arguments suggesting that strategic motives are important for graduationamong clinical PhD graduates which may compromise scientific output and quality. This study aimed to investigate the scientific outcome of clinical PhD theses. METHODS: A total of 841PhD theses from the Department of Clinical Medicine, University of Copenhagen, were concluded in 2013-2017. These theses were examined, and all published manuscripts were identified in online databases. Thesis bibliographics, publication activity and article/journal impact of the published manuscripts were obtained between 21 March and 18 September 2019. RESULTS: Overall, 2,845 manuscripts were embedded in the theses (3.4 ± 0.8 manuscripts/thesis, mean ± standard deviation). A total of 56% and 92% of the manuscripts were published at the time of thesis submission and observation, respectively. The SCImago Journal Rank was 2.1 ± 1.7 and 82% of the manuscripts were published in journals with a field-specific ranking in the best quartile. The mean field-weighted citation impact of the published manuscripts was 102% higher than the world average. CONCLUSIONS: The scientific outcome of clinical PhD theses was high as 92% of all manuscripts were published with a field-weighted journal ranking and citation impact above the world average, indicating that the productivity and quality of the clinical PhD theses are not compromised even though strategic motives is a driver for graduation. FUNDING: This study was funded by theGraduate School of the Faculty of Health and Medical Sciences, University of Copenhagen. TRIAL REGISTRATION: not relevant.
Subject(s)
Academic Dissertations as Topic , Clinical Medicine , Education, Graduate/statistics & numerical data , Publishing/statistics & numerical data , Biomedical Research , Databases, Bibliographic , Denmark , Education, Graduate/trends , Humans , Publishing/trends , UniversitiesABSTRACT
Peak fat oxidation rate (PFO) and the intensity that elicits PFO (Fatmax ) are commonly determined by a validated graded exercise test (GE) on a cycling ergometer with indirect calorimetry. However, for upper body exercise fat oxidation rates are not well elucidated and no protocol has been validated. Thus, our aim was to test validity and inter-method reliability for determination of PFO and Fatmax in trained men using a GE protocol applying double poling on a ski-ergometer. PFO and Fatmax were assessed during two identical GE tests (GE1 and GE2) and validated against separated short continuous exercise bouts (SCE) at 35%, 50%, and 65% of VÌO2peak on the ski-ergometer in 10 endurance-trained men (VÌO2peak : 65.1 ± 1.0 mL·min-1 ·kg-1 , mean ± SEM). Between GE tests no differences were found in PFO (GE1: 0.42 ± 0.03; GE2: 0.45 ± 0.03 g·min-1 , P = .256) or Fatmax (GE1: 41 ± 2%; GE2: 43 ± 3% of VÌO2peak , P = .457) and the intra-individual coefficient of variation (CV) was 8 ± 2% and 11 ± 2% for PFO and Fatmax , respectively. Between GE and SCE tests, PFO (GEavg : 0.44 ± 0.03; SCE; 0.47 ± 0.06 g·min-1 , P = .510) was not different, whereas a difference in Fatmax (GEavg : 42 ± 2%; SCE: 52 ± 4% of VÌO2peak , P = .030) was observed with a CV of 17 ± 4% and 15 ± 4% for PFO and Fatmax , respectively. In conclusion, GE has a high day-to-day reliability in determination of PFO and Fatmax in trained men, whereas it is unclear if PFO and Fatmax determined by GE reflect continuous exercise in general.