Comparing Muscle Oxygenation and Peak Blood Lactate Concentration in Division 1 College Middle-Distance Athletes: A Speed Reserve Ratio Analysis

Background—Near infrared spectroscopy can be used in non-invasive monitoring of changes in skeletal muscle oxygenation in exercising subjects.Objective—To evaluate whether this method can be used to assess metabolic capacity of...

O objetivo deste estudo foi verificar, em judocas masculinos das classes Juvenil-A (15 a 17 anos de idade; n = 6), Júnior (18 a 20 anos de idade; n = 5) e Sênior (acima de 21 anos de idade; n = 4), a relação entre variáveis fisiológicas e metabólicas em testes laboratoriais e em situação de luta e compará-las. Para isso foram realizados testes em três situações distintas: teste em esteira rolante (TE); teste em cicloergômetro para membros superiores (TCMS); situação de luta (SL). A partir destes testes foi verificado se havia diferença entre os três grupos quanto à: velocidade de limiar anaeróbio (VLAn); freqüência cardíaca correspondente à VLAn; pico do consumo de oxigênio, pico da concentração de lactato sangüíneo c pico da freqüência cardíaca durante TCMS; concentração de lactato sangüíneo e percepção subjetiva do esforço (escala de Borg, 1982) após cada uma das lutas. Os principais resultados obtidos foram: a) correlação negativa significante entre a VLAn e o pico da concentração de lactato após cada uma das lutas; b) correlação significante entre a percepção do esforço e o pico da concentração de lactato após a luta 1 (r = 0,8073; p < 0,001); c) a classe Sênior (10,2 ± 2,7 mM) apresentou maiores valores da concentração de lactato sangüíneo após o TCMS quando comparada à classe Juvenil-A (6,7 ±1,1 mM); d) os judocas da classe Júnior (17 ± 1) terminaram a terceira luta com maior grau de fadiga, segundo a escala de Borg (1982), do que a classe Juvenil-A (13 ± 2); e) não houve diferenças significantes quanto à VLAn, VO: pico no TCMS, lactato após SL, indicando que, ao menos fisiologicamente, as classes são bastante semelhantes

The influence of preceding diet (mixed, MD; carbohydrate CD; protein PD) on performance during high intensity endurance cycling was examined in six middle distance runners. Subjects undertook cycle ergometer exercise at a workload equivalent to 80% VO2 max until exhaustion following each of the three dietary regimens. Dietary analyses were performed using a computerised evaluation technique and cardiorespiratory, blood glucose and lactate responses to exercise were measured along with exercise time to exhaustion. Significant differences in carbohydrate and protein intakes were noted between respective diets as well as significantly higher total energy intake in MD (P less than 0.05). A significant relationship was observed between carbohydrate intake and exercise time to exhaustion (r = 0.59, P less than 0.05). No significant differences were noted in cardiorespiratory measures or blood glucose response after exhaustive exercise between the three dietary regimens but peak blood lactate concentration was lower following PD (P less than 0.05). Total time to exhaustion was significantly higher on CD (1070.0 +/- 106.7 s) than on PD (642.5 +/- 84.3 s, P less than 0.01). Performance time on MD (895.7 +/- 84.3 s) did not differ significantly for performance time on either CD or PD. It was concluded that dietary manipulation significantly improves exercise time to exhaustion during short term, high intensity cycling.

To determine the change in muscle oxygenation in response to progressively increasing work rate exercise, muscle oxyhemoglobin + oxymyoglobin saturation was measured transcutaneously with near infrared spectroscopy in the vastus lateralis muscle during cycle ergometry. Studies were done in 11 subjects while gas exchange was measured breath-by-breath. As work rate was increased, tissue oxygenation initially either remained constant near resting levels or, more usually, decreased. Near the work rate and metabolic rate where significant lactic acidosis was detected by excess CO2 production (lactic acidosis threshold, LAT), muscle oxygenation decreased more steeply. As maximum oxygen uptake (VO2max) was approached, the rate of desaturation slowed. In 8 of the 11 subjects, tissue O2 saturation reached a minimum which was sustained for 1-3 min before VO2max was reached. The LAT correlated with both the VO2 (r = 0.95, P < 0.0001) and the work rate (r = 0.94, P < 0.0001) at which the rate of tissue O2 desaturation accelerated. These results describe a consistent pattern in the rate of decrease in muscle oxygenation, slowly decreasing over the lower work rate range, decreasing more rapidly in the work rate range of the LAT and then slowing at about 80% of VO2max, approaching or reaching a minimum saturation at VO2max.

Aerobic and anaerobic capacities are critical determinants of performance in middle-distance and long-distance running. Middle-distance runners (800m-1500m) rely on both anaerobic and aerobic energy systems, whereas long-distance runners (5000m and above) primarily depend on aerobic metabolism. This study aims to compare the aerobic and anaerobic capacities of middle-distance and long-distance runners to understand their physiological adaptations and energy system contributions. The methodology involved assessing VO₂ max, lactate threshold, and anaerobic power output in a sample of competitive male and female runners. The results indicate significant differences in VO₂ max values, lactate accumulation, and recovery rates between the two groups, highlighting the importance of training specificity. This paper discusses the implications of these findings in sports science, training strategies, and performance enhancement for middle-distance and long-distance runners.

Blood lactate concentration during exercise is a reliable indicator of energy metabolism and endurance performance. Lactate is also present in sweat, and sweating plays an important role in thermoregulation, especially in hot conditions. Recently, wearable sensors have enabled the real-time and noninvasive measurement of sweat lactate concentration, potentially serving as an alternative indicator of blood lactate response. However, the evidence regarding the relationship between sweat and blood lactate responses during incremental exercise in hot conditions is lacking. In a randomized cross-over design, six highly trained male runners completed two incremental treadmill tests under normal (20°C/50%RH) or hot (30°C/50%RH) conditions. The tests include 3-min running stages and 1-min recovery, starting at 12 km/h and increasing by 1 km/h at each stage. Blood and sweat lactate concentrations were measured at each stage to determine blood and sweat lactate thresholds (LT). Blood lactate concentrations were higher under hot conditions (p < 0.01), but there was no difference in the response pattern or velocity at blood LT between conditions. Significant early increase (p < 0.01) in sweat lactate and low velocity at sweat LT (p < 0.05) were observed under hot conditions. A significant correlation between blood and sweat lactate concentrations was found under normal conditions (p < 0.001) but not under hot conditions, and no significant correlations were observed between the velocity at blood and sweat LT. In conclusion, sweat lactate concentration does not consistently reflect blood lactate concentration during incremental exercise.

Purpose: Greco-Roman wrestling demands a complex interplay of aerobic and anaerobic energy systems. The purpose of this study was to conduct a comprehensive laboratory assessment of both aerobic and anaerobic performance capacities in elite Greco-Roman wrestlers using standardized ergometric protocols. Methods: Three elite male Greco-Roman wrestlers (heavyweight division, body mass 99-100 kg) competing at the national and international level underwent physiological testing at a national sports science laboratory. Aerobic capacity was assessed via a graded exercise test (GXT) on a treadmill ergometer with continuous breath-by-breath gas exchange analysis and post-exercise blood lactate measurement. Anaerobic performance was evaluated using a 30-second Wingate anaerobic test (WAnT) on a mechanically braked cycle ergometer. Results: Maximal oxygen uptake (VO2max) ranged from 46 to 63 ml/min/kg. Notably, Athlete A exhibited a VO2max of 63 ml/min/kg, a value more characteristic of endurance-trained athletes than heavyweight combat sport competitors. His anaerobic threshold (AnT), identified via the onset of blood lactate accumulation (OBLA) method, occurred at 73% of VO2max (4.6 L/min). Peak anaerobic power (MAP) during the WAnT ranged from 1333 to 1652 W (13.46-16.52 W/kg), while mean anaerobic power ranged from 748 to 822 W (7.48-8.22 W/kg). Post-exercise peak blood lactate concentrations were 11.48-12.83 mmol/L. Conclusion: The findings demonstrate considerable inter-individual variability in both aerobic and anaerobic capacities among elite heavyweight Greco-Roman wrestlers. The exceptionally high VO2max observed in Athlete A underscores that elite wrestling performance may be supported by aerobic capacities well above previously reported norms for this weight class. The relatively low AnT as a percentage of VO2max suggests that targeted training to elevate the lactate threshold could yield further performance improvements. Training zone recommendations based on individualized physiological profiling are presented.

This study aimed to investigate the effects of 4-week continuous hypoxic training (CHT) on skeletal muscle oxygenation and hemodynamics, assessed using functional near-infrared spectroscopy (NIRS) and blood oxygenation level-dependent functional magnetic resonance imaging (fMRI-BOLD). Twenty-six healthy male participants were randomly assigned to CHT group (FiO₂ = 14.8-15.3%) or a normoxic training (CON) group (FiO₂ = 20.3-20.8%). Participants underwent a 4-week supervised treadmill endurance training program at their ventilatory anaerobic threshold. Assessments included that muscle oxygen saturation (SmO₂) measurements using NIRS during graded exercise, and fMRI-BOLD imaging during ischemia-reperfusion to evaluate skeletal muscle perfusion and oxygenation in pre- and post-intervention. Significant increases were observed in SmO₂ at 20% (68.43 ± 5.90 vs 62.53 ± 6.70), 40% (64.50 ± 7.46 vs 55.20 ± 7.43), 60% (54.42 ± 3.71 vs 45.63 ± 5.99), 80% (45.97 ± 5.91 vs 41.18 ± 6.40), and 100% (36.04 ± 6.62 vs 27.57 ± 5.66) exercise intensities (p < 0.046) in CHT group as compared to CON group. Additionally, PHV (p < 0.011), MIV (p < 0.003), TTP (p = 0.024), THIM (p < 0.045), and TTR (p < 0.003) were significantly improved after 4-week CHT intervention as compared to normoxic training, suggesting enhanced vascular reactivity and oxygen utilization efficiency. These findings demonstrate that CHT may enhance skeletal muscle oxygenation and perfusion, suggesting potential utility in endurance training and rehabilitation intervention by improving skeletal muscle oxygenation and perfusion, as evidenced by increased SmO₂ and enhanced BOLD responses, suggesting potential utility in endurance training and rehabilitation contexts. The application of fMRI-BOLD and NIRS provides novel insights into microvascular adaptations. 2023112H on 2023/06/30.

For the purpose of comparing the response in local skeletal muscle oxygenation and blood lactate concentration during incremental exercise, 8 female finswimmers were recruited to take an incremental exercise on a cycle ergometer. Muscle oxygenation in right vastus lateralis (VL) were monitored by continuous wave near infrared spectroscopy (CW NIRS), respiratory gas exchange and blood lactate concentration ([La]_b) were simultaneously measured by a metabolic system and a portable blood lactate analyzer respectively. NIRS measurements showed a muscle oxygenation index inflection point (OIip), from which the muscle oxygenation started to decrease dramatically. Significant correlations have been found between OIip and blood lactate threshold identified at the lowest [La]_b value which was &gt;0.5 mmol/L lower than that obtained at the following workload. These results might suggest that the CW NIRS measurement could be applied to monitor lactate threshold noninvasively.

Background. Endurance training has an essential role in improving the aerobic capacity and postponing the onset of exhaustion that can be beneficial to enhancing the performance. Handball involves both aerobic and anaerobic energy systems in the human body. Therefore, it becomes crucial to comprehend how training influences physiological variables such as anaerobic threshold and blood lactate concentration. Objectives. The objective of this study was to examine the effect of an endurance training program on anaerobic threshold and blood lactate concentration in Bangladeshi female handball players. Materials and methods. A total of sixty-four female athletes were selected using a purposive random sampling technique. The participants were randomly divided into two groups: 32 in the experimental group and 32 in the control group. A blood lactate analyzer, pulse oximeter, and treadmill test according to the Bruce protocol were used to assess blood lactate concentration, anaerobic threshold, resting heart rate, and maximum heart rate. Results. The study observed a significant improvement in the experimental group, including a reduction in resting blood lactate concentration from 1.72 ± 0.15 mmol/L to 1.42 ± 0.12 mmol/L at the post-training phase. Additionally, there was an increase in onset of blood lactate accumulation from 4.51 ± 0.26 mmol/L to 4.73 ± 0.15 mmol/L, and an increase in speed at lactate threshold from 7.0 ± 0.0 km/h to 7.49 ± 0.19 km/h. It was also noted a considerable enhancement in the control group for variables such as resting heart rate, maximum heart rate, resting blood lactate concentration, and peak lactate concentration due to regular handball participation. Cohen’s d was calculated to determine the effect size of endurance training. An independent t-test also revealed substantial differences between the experimental and control groups (p &lt; 0.05). Conclusions. The findings of this study indicate a significant effect of endurance training on the anaerobic threshold and blood lactate concentration in Bangladeshi female handball players.

Near-infrared spectroscopy (NIRS) is a focus of attention in the research field of biomedical photonics. The concentration of HbO<SUB>2</SUB> in human skeletal muscle has been measured noninvasive NIRS using a portable tissue oximeter continuously when the subjects did incremental exercises on a power bicycle. Blood lactate is one of traditional physical research subjects which is applied most widely. We study blood volume in the tissue of sportsmen when they are subjected by the incremental physical load, simultaneously detecting some parameters such as the heart rate, maximal oxygen absorption and the concentration of blood lactate. As the intensity of exercises was heightened, the concentration of blood lactate and blood volume in tissue increased, while the concentration of HbO<SUB>2</SUB> decreased. Thus the rudimental characteristics of energy consumption and supply during hypoxia and aerobic exercises are investigated. By discovering the relationship between blood lactate in human skeletal muscle and blood oxygenation, a novel approach for measuring blood lactate noninvasively and assessing the sports ability could be provided. Furthermore, it is possible to assess the fatigue state with tissue oximeter to monitor the human sports intensity noninvasively and dynamically.

This study aimed to compare the effectiveness of three recovery protocols on muscle oxygenation, blood lactate, and subsequent performance during a 200-m repeated swimming. Twelve swimmers (6 females and 6 males) from Chulalongkorn University swimming club completed three sessions of two consecutive 200-m front crawl trials separated by one of three recovery protocols: a 15-min of active recovery (AR), a 15-min of passive recovery (PR), and a recovery combination of 5-min of active and 10-min of passive recovery (CR) by using a counterbalance design. Skeletal muscle oxygenation, blood lactate concentration (BL), arterial oxygen saturation (SaO2), and heart rate (HR) were measured at rest, immediately after a trial, and at 5, 10, and 15 minutes of recovery. Two-way ANOVA (recovery x time) with repeated measures was used to determine the main and interaction effects on measured variables. One-way ANOVA followed by Tukey test were used to locate the mean differences.in all variables. A level of significant was set at p-value &lt;.05. The results revealed no significant changes in swimming time observed between trials (first vs. second) across recovery conditions. Tissue saturation index (TSI), as an indicator of oxygenated tissue, rapidly declined (P &lt; .05) immediately after a 200-m front crawl swim, and then gradually returned (P &lt; .05) to above baseline during CR, but not AR and PR after 15-min of recovery. Oxyhemoglobin (O2Hb) levels at biceps femoris significantly decreased (P &lt; .05) while deoxyhemoglobin (HHb) levels significantly increased (P &lt; .05) immediately after a 200-m swim compared with baselines in all conditions. These changes, however, were recovered (P &lt; .05) as early as after 5-min of recovery, regardless of conditions, with a fully return to baseline observed after 15-min of recovery. Interestingly, the significant reductions in blood lactate and heart rate were concomitant with the change in TSI during the recovery period. Our results indicated that the CR in the present study was more effective in enhancing the muscle reoxygenation after a 200-m front crawl swim compared with AR and PR. However, such benefit was not directly translated to the improvement of subsequent performance.

The selection of cadence during cycling may be determined by a number of factors, including the degree of oxygenation in the exercising skeletal muscle. The purpose of this study was to determine the degree of muscle oxygenation associated with different cycling cadences and exercise intensities, and its putative role in the choice of self‐selected cadence during cycling. We recorded cardiopulmonary and metabolic responses to cycling at exercise intensities of 70% and 90% of the ventilatory threshold (Tvent), and used near‐infrared spectroscopy to determine tissue saturation index as a measure of skeletal muscle (vastus lateralis) oxygenation. Twelve participants cycled at cadences of 30, 50, 70, 90, and 110 revolutions per minute (rpm), each for 4 min, in a randomized sequence, interspersed with active recovery periods. Despite cardiopulmonary and metabolic responses being greater at 90% than at 70% Tvent, and at 110 rpm compared with lower cadences, vastus lateralis oxygenation was not different between the two exercise intensities and five cadences tested. Our results indicate that skeletal muscle tissue saturation index is not substantially affected during cycling for short periods of time at constant, moderate exercise intensity at cadences between 30 and 110 rpm, suggesting that skeletal muscle oxygenation may not be an important negative feedback signal in the choice of self‐selected cadence during cycling at moderate exercise intensity.

Endothelial dysfunction and reduced nitric oxide (NO) signaling are key abnormalities leading to skeletal muscle oxygen delivery-utilization mismatch and poor physical capacity in patients with heart failure with reduced ejection fraction (HFrEF). Oral inorganic nitrate supplementation provides an exogenous source of NO that may enhance locomotor muscle function and oxygenation with consequent improvement in exercise tolerance in HFrEF. Thirteen patients (left ventricular ejection fraction ≤40%) were enrolled in a double-blind, randomized crossover study to receive concentrated nitrate-rich (nitrate) or nitrate-depleted (placebo) beetroot juice for 9 days. Low- and high-intensity constant-load cardiopulmonary exercise tests were performed with noninvasive measurements of central hemodynamics (stroke volume, heart rate, and cardiac output via impedance cardiography), arterial blood pressure, pulmonary oxygen uptake, quadriceps muscle oxygenation (near-infrared spectroscopy), and blood lactate concentration. Ten patients completed the study with no adverse clinical effects. Nitrate-rich supplementation resulted in significantly higher plasma nitrite concentration compared with placebo (240 ± 48 vs. 56 ± 8 nM, respectively; P < 0.05). There was no significant difference in the primary outcome of time to exercise intolerance between nitrate and placebo (495 ± 53 vs. 489 ± 58 s, respectively; P > 0.05). Similarly, there were no significant differences in central hemodynamics, arterial blood pressure, pulmonary oxygen uptake kinetics, skeletal muscle oxygenation, or blood lactate concentration from rest to low- or high-intensity exercise between conditions. Oral inorganic nitrate supplementation with concentrated beetroot juice did not present with beneficial effects on central or peripheral components of the oxygen transport pathway thereby failing to improve exercise tolerance in patients with moderate HFrEF.

High retest reliability is desirable in tests used to monitor athletic performance. The purpose of the present study was to determine the reliability of a 30-minute cycle test on a cycle ergometer (Lode, Groningen, Netherlands). Following an incremental VO 2max test, 10 highly-trained cyclists (mean ± SD; age = 30 ± 6 years; VO 2max = 67.7 ± 2.5 mL.kg -1 .min -1 ) completed three 30-minute cycling tests on a Lode cycle ergometer each separated by more than 48 hours. The cycle test implemented a fixed workload for 15-minutes (set at 70% VO 2max power output), followed by a 15-minute time-trial. Variables determined during the test were mean power (W mean ), blood lactate concentration at 15-minutes (BL 15 ), peak blood lactate concentration (BL peak ) and mean heart rate (HR mean ). W mean in trial 1 (312 ± 23 W) increased by 0.8% (95% confidence interval: -0.7 to 2.3%) in trial 2 and by a further 0.4% (-0.3 to 1.1%) in trial 3. The typical error of measurement expressed as a coefficient of variation (CV%) for W mean was 1.3% (1.0 to 1.8%). The CV for BL 15 was 10.9% (8.3 to 15.9%), BL peak ; 8.4% (6.5 to 13.0%) and HR mean ; 2.4% (1.8 to 3.4%). The average intraclass correlations between trials were W mean : 0.98 (0.96 to 1.00), BL 15 : 0.94 (0.85 to 0.98), BL peak : 0.88 (0.71- 0.97) and HR mean : 0.88 (0.71 to 0.97). A strong correlation existed between VO 2max and PPO in the incremental test and W mean in the 30-minute TT ( r = 0.86, 0.93, respectively). The testing protocol performed on a Lode cycle ergometer in the current study is reproducible in highly-trained cyclists, making it a reliable method for monitoring cycling performance.