HRTP, Prolonged Ergometer Exercise, and Single Sculling

Changes in irisin, inflammatory cytokines and aerobic capacity in response to three weeks of supervised sprint interval training in older men

BACKGROUND

This study investigated the effects of supervised short-term sprint interval training (SIT) on circulating irisin, interleukin (IL)-6 and tumour necrosis factor (TNF)-α concentrations, and aerobic capacity and body composition values in healthy older men.

METHODS

Eleven older men (63±8 years; 178.0±5.5 cm; 82.7±8.6 kg; 22.7±3.7% body fat) underwent SIT (6 repetitions of 30 s all-out cycling bouts with 4 min active recovery after each bout) three days a week for three consecutive weeks. Body composition measured by dual-energy X-ray absorptiometry, aerobic capacity assessed by direct peak oxygen consumption (VO<inf>2peak</inf>) test and morning fasting blood samples were obtained before and after a 3-week SIT intervention.

RESULTS

Nine supervised SIT sessions moderately (effect size [ES] =0.65; P<0.05) increased irisin concentrations (from 135.40±28.73 to 154.20±47.09 ng.mL^-1) together with moderate decreases (P<0.05) in IL-6 (ES=0.89; from 1.26±0.44 to 0.87±0.44 pg.mL^-1) and TNF-α (ES=0.64; from 5.10±1.23 to 4.31±1.20 pg.mL^-1) levels in older men. In addition, increase in VO<inf>2peak</inf> was significant but small (ES=0.25; P<0.05; from 36.0±7.1 to 37.8±6.7 mL.min.^-1kg^-1), while no changes (P>0.05) in body composition variables were observed after a short-term SIT period.

CONCLUSIONS

A 3-week SIT intervention with only nine training sessions increased circulating irisin concentrations, improved inflammatory profile and aerobic capacity without changes in body composition in healthy older men. Accordingly, a short-term SIT programme is a time efficient alternative for traditional aerobic training to improve metabolic health and aerobic capacity in older adults.

Effect of Sprint Interval Training on Cardiometabolic Biomarkers and Adipokine Levels in Adolescent Boys with Obesity

This study investigated the effect of supervised sprint interval training (SIT) on different cardiometabolic risk factors and adipokines in adolescent boys with obesity. Thirty-seven boys were allocated to either a SIT group (13.1 ± 0.3 years; body mass index [BMI]: 30.3 ± 0.9 kg·m^-2) or a control group (CONT) (13.7 ± 0.4 years; BMI: 32.6 ± 1.6 kg·m^-2). The SIT group performed 4-6 × 30 s all-out cycling sprints, interspersed with 4 min rest, for 3 sessions/week, during a 12-week period, while the non-exercising CONT group maintained a habitual lifestyle. Anthropometric measurements, triglycerides, fasting insulin and glucose, total cholesterol (TC), high- (HDLc) and low-density (LDLc) cholesterol, leptin and adiponectin in blood, cardiorespiratory fitness (CRF), and a metabolic syndrome severity risk score (MSSS) were calculated before and after the 12-week period. Compared to baseline values, a significant reduction in MSSS was seen in the SIT group after intervention. LDLc showed favorable changes in SIT compared to CONT (-0.06 ± 0.1 vs. 0.19 ± 0.01 mmol·L^-1; p = 0.025). Additionally, CRF increased in the SIT group compared to the CONT group (5.2 ± 1.1 vs. -2.1 ± 1.1 mL·min^-1·kg^-1, p < 0.001). Moreover, a 12-week all-out SIT training effectively improves cardiometabolic health in adolescent boys with obesity.

Increases in RPE Rating Predict Fatigue Accumulation Without Changes in Heart Rate Zone Distribution After 4-Week Low-Intensity High-Volume Training Period in High-Level Rowers

Purpose: The aim of this study was to investigate the interaction of training load quantification using heart rate (HR) and rating of perceived exertion (RPE)-based methodology, and the relationship between internal training load parameters and subjective training status (Fatigue) in high-level rowers during volume increased low-intensity training period.

Methods: Training data from 19 high-level rowers (age 23.5 ± 5.9 years; maximal oxygen uptake 58.9 ± 5.8 ml·min⁻¹·kg⁻¹) were collected during a 4-week volume increased training period. All individual training sessions were analyzed to quantify training intensity distribution based on the HR time-in-zone method (i.e., HR Z1, HR Z2, and HR Z3) determined by the first and second ventilatory thresholds (VT1/VT2). Internal training load was calculated using session RPE (sRPE) to categorize training load by effort (i.e., sRPE1, sRPE2, and sRPE3). The Recovery-Stress Questionnaire for Athletes (RESTQ-Sport) questionnaire was implemented after every week of the study period.

Results: No differences were found between the respective HR and effort-based zone distributions during the baseline week (p > 0.05). Compared to HR Z1, sRPE1 was significantly lower in weeks 2–4 (p < 0.05), while sRPE2 was higher in weeks 2–3 compared to HR Z2 (p < 0.05) and, in week 4, the tendency (p = 0.06) of the higher amount of sRPE3 compared to HR Z3 was found. There were significant increases in RESTQ-Sport stress scales and decreases in recovery scales mostly during weeks 3 and 4. Increases in the Fatigue scale were associated with the amounts of sRPE2 and sRPE3 (p = 0.011 and p = 0.008, respectively), while no associations with Fatigue were found for HR-based session quantification with internal or external training load variables.

Conclusion: During a low-intensity 4-week training period with increasing volume, RPE-based training quantification indicated a shift toward the harder rating of sessions with unchanged HR zone distributions. Moderate and Hard rated sessions were related to increases in Fatigue. Session rating of perceived exertion and effort-based training load could be practical measures in combination with HR to monitor adaptation during increased volume, low-intensity training period in endurance athletes.

Irisin, Fibroplast Growth Factor-21, and Follistatin Responses to Endurance Rowing Training Session in Female Rowers

Purpose: This study examined selected myokine responses to an endurance rowing training session, and whether metabolic demands of the acute aerobic rowing exercise together with training volume, aerobic capacity, and body composition variables affect potential exercise-induced changes in the myokine levels in female rowers. Methods: Fifteen national level female rowers [18.3 ± 1.6 years; 172.0 ± 5.0 cm, 67.5 ± 8.8 kg; maximal oxygen consumption (VO₂max): 47.2 ± 7.9 ml.min.^-1 kg^-1] performed a 1-h rowing ergometer exercise at the intensity of 70% of VO₂max [distance: 12.1 ± 1.1 km; energy expenditure (EE): 639 ± 69 kcal; heart rate (HR): 151 ± 7 beats.min^-1] followed by a 30-min recovery period. Venous blood samples were collected before and after exercise, and analyzed for irisin, fibroplast growth factor-21 (FGF-21), and follistatin conentrations. Results: Plasma irisin and FGF-21 concentrations were increased (by 8%; p = 0.013 and by 13%; p < 0.0001, respectively) immediately after the aerobic rowing exercise. Follistatin was significantly increased (by 11%; p = 0.001) only after the first 30 min of recovery. Exercise metabolic demand variables such as distance covered and total EE were correlated with the pre-to-post-exercise increases in FGF-21 concentrations (r = 0.52; p = 0.047 and r = 0.68; p = 0.005, respectively). Exercise-induced increases in irisin levels were related to aerobic capacity as measured by VO₂max (r = 0.53; p = 0.041) and training stress as measured by weekly training volume (r = 0.54; p = 0.039) in female rowers. Conclusion: Acute negative energy balance induced by a single endurance rowing training session elicited significant increases in irisin, FGF-21, and follistatin levels in national level female rowers. While exercise-induced increases in FGF-21 levels were associated with exercise metabolic demand measures, exercise-induced increases in irisin concentrations were related to aerobic capacity and training stress measures in female rowers.

The Effect of Lower Body Anaerobic Pre-Loading on Upper Body Ergometer Time Trial Performance

Pre-competitive conditioning has become a substantial part of successful performance. In addition to temperature changes, a metabolic conditioning can have a significant effect on the outcome, although the right dosage of such a method remains unclear. The main goal of the investigation was to measure how a lower body high-intensity anaerobic cycling pre-load exercise (HIE) of 25 s affects cardiorespiratory and metabolic responses in subsequent upper body performance. Thirteen well-trained college-level male cross-country skiers (18.1 ± 2.9 years; 70.8 ± 7.6 kg; 180.6 ± 4.7 cm; 15.5 ± 3.5% body fat) participated in the study. The athletes performed a 1000-m maximal double-poling upper body ergometer time trial performance test (TT) twice. One TT was preceded by a conventional low intensity warm-up (TT_low) while additional HIE cycling was performed 9 min before the other TT (TT_high). Maximal double-poling performance after the TT_low (225.1 ± 17.6 s) was similar (p > 0.05) to the TT_high (226.1 ± 15.7 s). Net blood lactate (La) increase (delta from end of TT minus start) from the start to the end of the TT_low was 10.5 ± 2.2 mmol L⁻¹ and 6.5 ± 3.4 mmol L⁻¹ in TT_high (p < 0.05). La net changes during recovery were similar for both protocols, remaining 13.5% higher in TT_high group even 6 min after the maximal test. VCO₂ was lower (p < 0.05) during the last 400-m split in TT_high, however during the other splits no differences were found (p < 0.05). Respiratory exchange ratio (RER) was significantly lower in TT_high in the third, fourth and the fifth 200 m split. Participants individual pacing strategies showed high relation (p < 0.05) between slower start and faster performance. In conclusion, anaerobic metabolic pre-conditioning leg exercise significantly reduced net-La increase, but all-out upper body performance was similar in both conditions. The pre-conditioning method may have some potential but needs to be combined with a pacing strategy different from the usual warm-up procedure.

Agreement between heart rate deflection point and maximal lactate steady state in young adults with different body masses

We examined the agreement between heart rate deflection point (HRDP) variables with maximal lactate steady state (MLSS) in a sample of young males categorized to different body mass statuses using body mass index (BMI) cut-off points. One hundred and eighteen young males (19.9 ± 4.4 years) underwent a standard running incremental protocol with individualized speed increment between 0.3 and 1.0 km/h for HRDP determination. HRDP was determined using the modified Dmax method called S.Dmax. MLSS was determined using 2-5 series of constant-speed treadmill runs. Heart rate (HR) and blood lactate concentration (La) were measured in all tests. MLSS was defined as the maximal running speed yielding a La increase of less than 1 mmol/L during the last 20 min. Good agreement was observed between HRDP and MLSS for HR for all participants (±1.96; 95% CI = -11.5 to +9.2 b/min, ICC = 0.88; P < 0.001). Good agreement was observed between HRDP and MLSS for speed for all participants (±1.96; 95% CI = -0.40 to +0.42 km/h, ICC = 0.98; P < 0.001). The same findings were observed when participants were categorized in different body mass groups. In conclusion, HRDP can be used as a simple, non-invasive and time-efficient method to objectively determine submaximal aerobic performance in nonathletic young adult men with varying body mass status, according to the chosen standards for HRDP determination.

Effects of Varying the Step Duration on the Determination of Lactate Thresholds in Elite Rowers

This study aimed to identify the minimum increment duration required to accurately assess 2 distinct lactate thresholds. A total of 21 elite rowers (12 women and 9 men) participated in this study, and each performed 8 or 9 rowing tests comprising 5 progressive incremental tests (3-, 4-, 5-, 7-, or 10-min steps) and at least three 30-min constant-intensity maximal lactate steady-state assessments. Power output (PO) at lactate threshold 1 was higher in the 3- and 4-min incremental tests. No other measures were different for lactate threshold 1. The PO at the second lactate threshold was different between most tests and was higher than the PO at maximal lactate steady state, except for the 10-min incremental test. Lactate threshold 2 oxygen consumption was higher in the 3-, 4-, and 5-min tests, but heart rate (HR) and rating of perceived exertion were not different between tests. Peak PO in the incremental tests was inversely related to the step durations (r2 = .86, P ≤ .02). Peak oxygen consumption was higher in the shorter (≤5 min) than the longer (≥7 min) incremental tests, whereas peak HR was not different between tests. These data suggest that for the methods used in this study, incremental exercise tests with step durations ≤7 min overestimate maximal lactate steady-state exercise intensity, peak physiological values are best determined using incremental tests with step durations ≤4 min, and HR measures are not affected by step duration, and therefore, prescription of training HRs can be made using any of these tests.

Physiological characteristics of elite dancers of different dance styles

The present investigation was aimed to study international level dancesport dancer's aerobic capacity during incremental test and competition simulation in relation to the gender, dance style and international ranking. A total of 30 couples (12 Standard, 7 Latin American and 11 Ten Dance; aged 22.8 ± 6.6 years male and 22.0 ± 6.4 years female) performed an incremental treadmill test and competition simulation. In this study for the first time we carried out longer than one round competition simulation and compared three different dancesport styles (Standard, Latin American and Ten Dance). The results showed that dancers of these three dance styles had similar aerobic capacity values. The average maximal oxygen consumption (VO2max) values were 59.6 ± 5.1 and 51.2 ± 6.2 ml · min(-1) · kg(-1) for male and female dancers, respectively. Competition simulation showed that Latin American Dance discipline is physiologically more intensive compared to Standard and Ten Dance styles especially for the female dancers. It appeared that male and female Standard dancers tended to perform at lower intensity than anaerobic threshold (AT) during competition simulation (male 97.3 ± 2.9%; female 97.9 ± 3.6%), while Latin (male 101.4 ± 2.9%; female 106.7 ± 5.9%) and Ten Dance (male 100.7 ± 6.4%; female 99.2 ± 5.6%) competition intensity was higher compared to AT level of athletes. The highest heart rate during competition simulation was always found during the last dances (Paso Double, Jive or Quickstep) and in the last round of each dance style. No significant relationship between VO2max values and international rankings was registered.

Comparação do ponto de deflexão da frequência cardíaca com a máxima fase estável de lactato em corredores de fundo

O objetivo do estudo foi comparar o ponto de deflexão da freqüência cardíaca (PDFC) visual e método DMAX com a máxima fase estável de lactato (MFEL). Treze corredores executaram teste incremental Vameval e testes de cargas retangulares (TCR). A velocidade do PDFC visual (14,3 ± 1,13km.h-1) foi significantemente maior que o DMAX (13,2 ± 1,35km.h-1) além de apresentarem correlação não significante. Entretanto, nenhuma dessas velocidades foram diferentes da MFEL (13,8 ± 0,90km.h-1) embora somente o PDFC visual tenha apresentado correlação significante com a MFEL (r = 0,75). A concentração de lactato sanguíneo não apresentou estabilidade em oito sujeitos no TCR na intensidade do PDFC visual o qual nos leva a concluir que este não é um índice confiável para estimativa da MFEL. No entanto, este índice pode ser usado como um indicador de capacidade aeróbia.

Phase of Oral Contraceptive Cycle and Endurance Capacity of Rowers

Eight female rowers ( M age = 21.0 yr., SD = 2.8), using a monophasic oral-contraceptive pill, performed a 1-hr. rowing ergometer test (intensity: 70% VO2max) during the active-pill and non active-pill phases of the oral contraceptive cycle. No significant differences were found in mean energy expenditure, oxygen consumption, respiratory exchange ratio, and heart rate during the endurance test at the two phases of the oral contraceptive cycle. Mean energy expenditure rate, carbohydrate energy expenditure, lipid energy expenditure, and blood lactate during the test were not statistically significantly different among the cycle phases. In conclusion, there was no observed difference in substrate oxidation and blood lactate level during endurance rowing at different phases of the oral contraceptive cycle in these endurance-trained rowers. Endurance-trained female athletes on oral contraceptives should not worry about the possible differences in substrate oxidation during everyday training at different phases of the oral contraceptive cycle.

Adiponectin and bone metabolism markers in female rowers: eumenorrheic and oral contraceptive users

This study investigated whether adiponectin, bone formation (osteocalcin) and bone resorption [type I carboxyterminal telopeptide (ICTP)] values are influenced by menstrual cycle phase and oral contraceptive use in female rowers. Twenty-four rowers divided into normally cycling athletes (NOC; no.=15) and athletes taking oral contraceptive pills (OC; no.=9) participated in this study. Fasting blood samples, body composition and aerobic capacity measurements were taken during the follicular (FP) and the luteal (LP) phases of the menstrual cycle. Adiponectin, insulin, glucose, insulin resistance, body composition and aerobic capacity did not fluctuate significantly during menstrual cycle in both groups. Osteocalcin and ICTP were lower (p<0.05) in OC compared with NOC, but did not change significantly across menstrual cycle phases in both groups. Estradiol and progesterone were not related to adiponectin, osteocalcin or ICTP (r<0.147; p>0.05). Adiponectin was correlated (p<0.05) with osteocalcin (r=0.452) and fat free mass (r=0.428), and osteocalcin was related (p<0.05) to insulin (r=-0.413), glucose (r=-0.486) and insulin resistance (r=-0.528). In conclusion, adiponectin was not affected by menstrual cycle phase and OC use in female rowers, while bone metabolism markers were lower in OC compared to NOC groups. Adiponectin and osteocalcin were interrelated and may characterise energy homeostasis in female athletes.

The effect of 4-week training period on plasma neuropeptide Y, leptin and ghrelin responses in male rowers

The aim was to investigate the effect of high-volume low intensity resistance training protocol combined with endurance training on plasma neuropeptide Y (NPY) concentration in rowers. Additionally, leptin and ghrelin, as markers for body energy balance concentrations, were monitored. 12 highly trained national and international level male rowers participated in this study. The participants were tested three times--after reference week (T1), after 2 weeks of high-volume training (T2) and after a recovery week (T3) for aerobic performance, energy intake and expenditure, and blood biochemical parameters. The submaximal rowing performance decreased significantly (P = 0.019) at T2. Fasting leptin decreased significantly (from 2.05 ± 0.88 to 1.28 ± 0.53 ng/mL; P = 0.009) at T2 and increased significantly (from 1.28 ± 0.53 to 1.79 ± 0.79 ng/mL; P = 0.002) at T3. Fasting ghrelin decreased significantly (from 980 ± 300.2 to 873.35 ± 198.6 pg/mL; P = 0.036) at T3 compared to T2, while no changes were found in fasting NPY. Significant decreases in exercise-induced leptin were observed at T2 (from 1.13 ± 0.5 to 1.08 ± 0.5 ng/mL; P = 0.012), PRE and POST test leptin values at T2 were significantly decreased compared to T1(1.40 ± 0.9 to 1.13 ± 0.5 and 1.44 ± 0.8 to 1.08 ± 0.5, respectively). Acute exercise-induced increases in NPY were found at T2 (from 128.1 ± 23.2 to 155.1 ± 28.9 pmol/L; P = 0.002) and at T3 (from 131.3 ± 20.5 to 159.7 ± 32.8 pmol/L, P = 0.004). In conclusion, the combination of high-volume training protocol and energy imbalance induces significant post-exercise changes in NPY, leptin, and ghrelin concentrations and decreases fasting leptin.

Special needs to prescribe exercise intensity for scientific studies

There is clear evidence regarding the health benefits of physical activity. These benefits follow a dose-response relationship with a particular respect to exercise intensity. Guidelines for exercise testing and prescription have been established to provide optimal standards for exercise training. A wide range of intensities is used to prescribe exercise, but this approach is limited. Usually percentages of maximal oxygen uptake (VO₂) or heart rate (HR) are applied to set exercise training intensity but this approach yields substantially variable metabolic and cardiocirculatory responses. Heterogeneous acute responses and training effects are explained by the nonuniform heart rate performance curve during incremental exercise which significantly alters the calculations of %HR_max and %HRR target HR data. Similar limitations hold true for using %VO_2max and %VO₂R. The solution of these shortcomings is to strictly apply objective submaximal markers such as thresholds or turn points and to tailor exercise training within defined regions.

Value of the Application of the Heart Rate Performance Curve in Sports

The heart rate performance curve (HRPC) has been shown to be nonlinearly related to work load. This phenomenon has been used to determine a defection point and to be related to the lactate anaerobic threshold. The original method was heavily criticized, and the method was challenged by several authors. However, some authors also demonstrated a high value for this method’s application in various sports conditions. Unfortunately, the HRPC was shown to be not uniform and three different patterns were found. Basic investigations have shown a dependence of the HR-defection on beta1-receptor sensitivity, which gave a plausible explanation of the phenomenon. Important details regarding the testing protocol and the method of turn point determination are given in this review. As a conclusion, we may state that based on numerous studies the method is plausible and valid to determine aerobic exercise performance in various laboratory ergometer and specific sports-related field conditions. Standard protocol conditions adjusted to the exercise performance level of subjects and a computer-supported determination of turn points are necessary to obtain reliable results. Large-scale investigations to validate the heart rate turn point with maximal lactate steady state are still needed. However, from the available literature, the application of this noninvasive method can be recommended to determine aerobic exercise performance in various sports. This noninvasive test is easy to perform repeatedly, which gives interesting possibilities for the monitoring of training adaptation in the short term, such as altitude training or specifc taper forms.

No effect of menstrual cycle phase on fuel oxidation during exercise in rowers

The aim of this investigation was to examine the effects of menstrual cycle phase on substrate oxidation and lactate concentration during exercise. Eleven eumenorrheic female rowers (18.4 ± 1.9 years; 172.0 ± 4.0 cm; 67.2 ± 8.4 kg; 27.7 ± 4.8% body fat) completed 1 h rowing ergometer exercise at 70% of maximal oxygen consumption (VO(2max)) during two different phases of the menstrual cycle: the follicular phase (FP) and the luteal phase (LP). Resting and exercise measurements of the whole body energy expenditure, oxygen consumption (VO(2)), respiratory exchange ratio (RER), substrate oxidation and lactate blood levels were made. Energy expenditure, VO(2) and heart rate during the 1-h exercise were not significantly different (P > 0.05) among menstrual cycle phases. Resting RER and RER during the entire 1 h exercise period were not significantly different among menstrual cycle phases. There was an increase (P < 0.05) in RER in the transition between rest and exercise and a further increase in RER occurred after the first 30 min of exercise at both menstrual cycle phases. Blood lactate concentrations significantly increased in the transition between rest and exercise and remained relatively constant during the whole 1 h of exercise in both menstrual cycle phases. No menstrual cycle phase effect (P > 0.05) was observed for blood lactate concentrations. In conclusion, our results demonstrated no effect of menstrual cycle phase on substrate oxidation and blood lactate concentration during rowing exercise at 70% of VO(2max) in athletes. Normally menstruating female rowers should not be concerned about their menstrual cycle phase with regard to substrate oxidation in everyday training.

Non-invasive Indices for the Estimation of the Anaerobic Threshold of Oarsmen

This study compared four common non-invasive indices with an invasive index for determining the anaerobic threshold (AT) in 22 adult male rowers using a Concept2 rowing ergometer. A criterion-standard progressive incremental test (invasive method) measured blood lactate concentrations to determine the 4 mmol/l threshold (La4-AT) and Dmax AT (Dm-AT). This was compared with three indices obtained by analysis of respiratory gases and one that was based on the heart rate (HR) deflection point (HRDP) all of which used the Conconi test (non-invasive methods). In the Conconi test, the HRDP was determined whilst continuously increasing the power output (PO) by 25 W/min and measuring respiratory gases and HR. The La4-AT and Dm-AT values differed slightly with respect to oxygen uptake, PO and HR however, AT values significantly correlated with each other and with the four non-invasive methods. In conclusion, the non-invasive indices were comparable with the invasive index and could, therefore, be used in the assessment of AT during rowing ergometer use. In this population of elite rowers, Conconi threshold (Con-AT), based on the measurement of HRDP tended to be the most adequate way of estimating AT for training regulation purposes.