Impact of Fruit and Vegetable Enzyme Supplementation on Aerobic Performance and Lactate Response in Older Adults Following High-Intensity Interval Exercise Through Exergaming: Randomized Experimental Matched-Pair Study.

Background: Exercise offers substantial health benefits but can induce oxidative stress and inflammation, especially in high-intensity formats such as high-intensity interval exercise (HIIE). Exergaming has become an effective, enjoyable fitness tool for all ages, particularly older adults. Enzyme supplements may enhance exercise performance by improving lactate metabolism and reducing oxidative stress. Objective: This study investigates the efficacy of fruit and vegetable enzyme supplementation in modulating fatigue and enhancing aerobic capacity in older adults following HIIE through exergaming. Methods: The study recruited 16 older adult female participants and allocated them into 2 distinct groups (enzyme and placebo) based on their pretest lactate levels. This division used pairwise grouping to guarantee comparability between the groups, ensuring the integrity of the results. They engaged in HIIE using Nintendo Switch Ring Fit Adventure, performing 8 sets of 20 seconds of maximum effort exercise interspersed with 30 seconds of rest, totaling 370 seconds of exercise. Key metrics assessed included blood lactate levels, heart rate, rating of perceived exertion, and training impulse. Participants in the enzyme group were administered a fruit and vegetable enzyme supplement at a dosage of 30 mL twice daily over a period of 14 days. Results: The enzyme group showed significantly lower blood lactate levels compared to the placebo group, notably after the fourth (mean 4.29, SD 0.67 vs mean 6.34, SD 1.17 mmol/L; P=.001) and eighth (mean 5.84, SD 0.63 vs mean 8.20, SD 1.15 mmol/L; P<.001) exercise sessions. This trend continued at 5 minutes (mean 6.85, SD 0.82 vs mean 8.60, SD 1.13 mmol/L; P=.003) and 10 minutes (mean 5.91, SD 1.16 vs mean 8.21, SD 1.27 mmol/L; P=.002) after exercise. Although both groups exceeded 85% of their estimated maximum heart rate during the exercise, enzyme supplementation did not markedly affect the perceived intensity or effort. Conclusions: The study indicates that fruit and vegetable enzyme supplementation can significantly reduce blood lactate levels in older adults following HIIE through exergaming. This suggests a potential role for these enzymes in modulating lactate production or clearance during and after high-intensity exercise. These findings have implications for developing targeted interventions to enhance exercise tolerance and recovery in older adults.

Blood Lactate Levels during Therapeutic Hypothermia and Neurodevelopmental Outcome or Death at 18-24 Months of Age in Neonates with Moderate and Severe Hypoxic-Ischemic Encephalopathy.

INTRODUCTION: Blood lactate levels in neonates with hypoxic-ischemic encephalopathy (HIE) vary, and their impact on neurodevelopmental outcome is unclear. We assessed blood lactate course over time in neonates with HIE during therapeutic hypothermia (TH) and investigated if blood lactate values were associated with neurodevelopmental outcome at 2 years of age. METHODS: This is a retrospective cohort study of neonates with HIE born between 2013 and 2019, treated at the University Children's Hospital Zurich. We recorded blood lactate values over time and calculated time until lactate was ≤2 mmol/L. Neurodevelopmental outcome was assessed at 18-24 months of age using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III), and categorized as favorable or unfavorable. We investigated associations between blood lactate values and outcome using logistic regression and adjusted for Sarnat stage. RESULTS: 33/45 neonates (69%) had a favorable and 14 (31%) an unfavorable neurodevelopmental outcome. Mean initial lactate values were lower in the favorable (13.9 mmol/L, standard deviation [SD]: 2.9) versus unfavorable group (17.1 mmol/L, SD 3.2; p = 0.002). Higher initial and maximal blood lactate levels were associated with unfavorable outcome, also when adjusted for Sarnat stage (adjusted odds ratio [aOR]: 1.37, 95% CI: 1.01-1.88, p = 0.046, and aOR: 1.35, 95% CI: 1.01-1.81, p = 0.041, respectively). CONCLUSION: In neonates with HIE receiving TH, initial and maximal blood lactate levels were associated with neurodevelopmental outcome at 18-24 months of age, also when adjusted for Sarnat stage. Further investigations to analyze blood lactate as a biomarker for prognostic value are needed.

Effect of active recovery using individual maximum exercise capacity: a pilot study.

[Purpose] The intensity of active recovery (AR) for performance recovery is often determined using breath gas analyzers and other special equipment. However, such procedures are difficult to perform in the field or where facilities are inadequate. Although several AR methods using simple patient-derived information have been proposed, only a few have specifically addressed their immediate effects. The present study aimed to quantify the immediate effects of AR, which was determined using the maximum exercise capacity calculated using a physical fitness test without specialized devices. [Participants and Methods] Thirty-two healthy male participants were equally divided into AR and control groups. Each group performed squat jumps, followed by a recovery intervention of jogging at a set intensity in the AR group or rest in a seated position in the control group. Standing long jumps performed before and after the squat jumps as well as after the intervention were analyzed. [Results] The recovery rate for standing long jumps was significantly higher in the AR group than in the control group. [Conclusion] The results of this pilot study indicate that the implementation of AR based on maximum exercise capacity may enhance performance recovery and requires further validation in larger studies.

Effect of One Session of Muscle Blood Flow Restriction Training Versus Normal Training on Blood Lactate Level.

Objectives: Blood flow restriction training (BFRT) is useful for improving muscle strength. However, it involves a long training time and is unsuitable for vigorous exercise. Muscle blood flow restriction training (MBFRT), which uses multiple parallel pneumatic cuffs (MPCs) to compress large areas of the extremities and restrict blood flow, was subsequently developed to address these issues. This study compared the effects of MBFRT with normal training (NT). Methods: Ten healthy adults underwent low-intensity MBFRT. MPC pressure was increased to 200 mmHg just before training. The exercise was a bodyweight half-squat. Three sets of 30 squats were performed. Two weeks later, the participants underwent NT with the same exercise. Blood lactate levels were measured before the start of training and at 1 and 5 min after training. The Borg index was also measured at the end of the training. Results: The blood lactate level was elevated at 1 min after MBFRT and NT. The elevated blood lactate level was maintained at 5 min after MBFRT, whereas the lactate level was significantly decreased at 5 min after NT. The Borg index at the end of the training was significantly higher in MBFRT than in NT. Conclusions: Lactic acid accumulates in the muscles during low-intensity MBFRT, thereby initiating type II fiber activity.

A study of the effect of half-day climatotherapy on changes in salivary cortisol levels.

In our previous study setting, climatotherapy programme consisted of six sessions - four in the mid-mountain area and two in a flat park. For all sessions, the subjects underwent climatotherapy in the morning under slightly cool conditions. During each session, the subjects' blood pressure, pulse rate, skin temperature, blood lactate, salivary cortisol and mood profile were recorded, and meteorological data were collected at the sites. We hypothesised that exercise habits, changes in mood profile and effective temperatures during the session, and physical exertion during the climatic terrain cure would affect salivary cortisol levels. Subjects were 30 (spring) and 29 (autumn). Multiple linear regression analyses were performed to examine the determinants of the change in salivary cortisol levels. In the mountain setting, salivary cortisol was elevated, even though the sessions took place in the descending phase of the circadian salivary cortisol variation; however, the post-session cortisol increase was not significant. Increased post-session salivary cortisol was significantly associated with female gender, older age, higher BMI, lower body fat, less daily physical activity, increased blood lactate, increased 'Tension-Anxiety' and 'Depression-Dejection' moods, and decreased 'Anger-Hostility' mood. The increase in cortisol may have been due to older age, a predominance of females, and the increased blood lactate due to the mountainous terrain. In the flat park, the significant decrease in postsession salivary cortisol was related to the descending circadian phase of circadian cortisol variation and the low physical demands of the sessions.

Difference in badminton-specific endurance evaluated by a newly developed on-court test between competitive levels: A pilot study of female players.

We developed a test to evaluate badminton-specific endurance. The study included 10 female badminton players. Five participants were ranked in Japan's top 100 national rankings (ranked), whereas the others were unranked (unranked). Participants reacted quickly with badminton-specific steps from the base center to the four sensors at each corner of a singles badminton court. On each set, they reacted eight times to randomized instructions at stage-specific intervals (1.2, 1.0, and 0.8 s for stages 1, 2, and 3, respectively), which were performed six times with a rest of 20 s in each stage (8 movements × 6 sets × 3 stages). On a different day, participants ran on a treadmill as a comparative test. Blood lactate concentration (BLa) was measured on each test. In the badminton-specific test, ranked participants had lower BLa (4.2 ± 1.7 mM vs. 6.3 ± 3.1 mM), with medium or large effect sizes. The average reach time to sensors was shorter in ranked participants (1.56 ± 0.03 s vs. 1.62 ± 0.07 s), with medium or large effect sizes. BLa was similar between groups, with trivial or small effect sizes in the running test. These results suggest that the newly developed test can evaluate badminton-specific endurance.

Fatigue and Metabolic Responses during Repeated Sets of Bench Press Exercise to Exhaustion at Different Ranges of Motion.

This study compared the acute effects of different ranges of motion (ROM) on fatigue and metabolic responses during repeated sets of bench press exercise. Ten resistance trained men performed three sets to momentary failure with two-min rest intervals at three different ROM: full ROM (FULL), and partial ROM in which the barbell was moved either at the bottom half (BOTTOM) or the top half (TOP) of the full barbell vertical displacement. In TOP, a higher load was lifted, and a higher total number of repetitions was performed compared to FULL and BOTTOM (130 ± 17.6 vs. 102.5 ± 15.9 vs. 98.8 ± 17.5 kg; 55.2 ± 9.8, 32.2 ± 6.5 vs. 49.1 ± 16.5 kg, respectively p < 0.01). Work per repetition was higher in FULL than TOP and BOTTOM (283 ± 43 vs. 205 ± 32 vs. 164 ± 31 J/repetition, p < 0.01). Mean barbell velocity at the start of set 1 was 21.7% and 12.8% higher in FULL compared to TOP and BOTTOM, respectively. The rate of decline in mean barbell velocity was doubled from set 1 to set 3 (p < 0.01) and was higher in FULL than both TOP and BOTTOM (p < 0.001). Also, the rate of mean barbell velocity decline was higher in BOTTOM compared to TOP (p = 0.045). Blood lactate concentration was similarly increased in all ROM (p < 0.001). Training at TOP ROM allowed not only to lift a higher load, but also to perform more repetitions with a lower rate of decline in mean barbell velocity. Despite the lower absolute load and work per repetition, fatigue was higher in BOTTOM than TOP and this may be attributed to differences in muscle length.

Changes of Anaerobic Power and Lactate Concentration following Intense Glycolytic Efforts in Elite and Sub-Elite 400-meter Sprinters.

400-m races are based on anaerobic energy metabolism, they induce significant muscle fatigue, muscle fiber damage, and high blood lactate (LA) concentration. Despite extensive research on sprint training, our understanding of the training process that leads to world-class sprint performance is rather limited. This study aimed to determine differences in LA concentration and anaerobic power using jumping tests after an intense glycolytic effort in a group of elite and sub-elite 400-m runners. One hundred thirty male runners were divided into two groups: elite (n = 66, body mass = 73.4 ± 7.8 kg, body height = 182.1 ± 6.2 cm, age = 20.8 ± 4.0 y) running the 400-m dash below 50 s and sub-elite (n = 64, body mass = 72.0 ± 7.1 kg, body height = 182.1 ± 5.2 cm, age = 20.8 ± 4.0 y) with a 400-m personal best above 50 s. The power of the countermovement and the sequential squat jumps was measured in two sets after a warm-up, followed by two intermittent 30-s Wingate tests. LA concentration was measured eight times. It was observed that elite athletes achieved significantly higher power in both types of jumps. The maximum post-exercise LA concentration was significantly lower in the sub-elite group after the 3rd, the 6th, the 9th, and the 20th min after the cessation of two Wingate tests (p < 0.001). The rate of LA accumulation after exercise and the rate of LA utilization did not differ between the groups. It can be concluded that elite and non-elite runners differ in higher LA production but not in LA utilization. Anaerobic power and LA concentration seem to differentiate between 400 elite and sub-elite performance.

Deciphering recovery paradigms: Foam rolling's impact on DOMS and lactate dynamics in elite volleyball athletes.

This study examines the effects of Self-Myofascial Release (SMR) techniques on post-exercise recovery in elite volleyball athletes. Through a controlled investigation involving eighteen Chinese Men's National Volleyball Team athletes, the research assessed the impact of foam rolling (FR) versus passive recovery (PAS) on blood lactate clearance and Delayed Onset Muscle Soreness (DOMS), as measured by Visual Analogue Scale (VAS) scores. Findings indicated that FR significantly reduces VAS scores and facilitates lactate clearance when compared to PAS, suggesting foam rolling may enhance post-exercise recovery. While confirming foam rolling's benefits, this research calls for further exploration into recovery mechanisms, emphasizing a cautious interpretation of foam rolling as part of a comprehensive recovery strategy.

Hemodynamic and Metabolic Responses to Moderate and Vigorous Cycle Ergometry in Men Who Have Had Transtibial Amputation.

Adults who have had an amputation face barriers to having an active lifestyle which attenuates cardiorespiratory fitness. Prior studies in amputees typically involve treadmill walking or arm ergometry, yet physiological responses to bilateral leg cycling are less understood. This study assessed the hemodynamic and metabolic responses to moderate and vigorous cycle ergometry in men who have had a transtibial amputation (TTA). Five men who had had a unilateral TTA (age = 39 ± 15 yr) and six controls (CONs) without an amputation (age = 31 ± 11 yr) performed two 20 min bouts of cycling differing in intensity. Cardiac output (CO), stroke volume (SV), and oxygen consumption (VO2) were measured during moderate intensity continuous exercise (MICE) and high intensity interval exercise (HIIE) using thoracic impedance and indirect calorimetry. In response to MICE and HIIE, the HR and VO2 levels were similar (p > 0.05) between groups. Stroke volume and CO were higher (p < 0.05) in the CONs, which was attributed to their higher body mass. In men with TTAs, HIIE elicited a peak HR = 88%HRmax and substantial blood lactate accumulation, representing vigorous exercise intensity. No adverse events were exhibited in the men with TTAs. The men with TTAs show similar responses to MICE and HIIE versus the CONs.

Progressive Arm Cycling Ergometry With 3- And 5-Minute Stage Durations Yields Similar Estimates of Substrate Oxidation in Healthy Adults.

Arm cycling ergometry (ACE) leads to a lower maximal oxygen uptake (VO2max) than cycling which is related to a smaller active muscle mass. This study compared estimates of fat and carbohydrate oxidation (FOx and CHOOx) between progressive exercise protocols varying in stage duration in an attempt to create a standard exercise protocol for determining substrate metabolism using ACE. Four men and seven women (age = 24 ± 9 yr) unfamiliar with ACE completed incremental exercise to determine peak power output and VO2peak. During two subsequent sessions completed after an overnight fast, they completed progressive ACE using 3- or 5-min stages during which FOx, CHOOx, and blood lactate concentration (BLa) were measured. Results showed no difference (p > 0.05) in FOx, CHOOx, or BLa across stage duration, and there was no difference in maximal fat oxidation (0.16 ± 0.08 vs. 0.13 ± 0.07 g/min, p = 0.07). However, respiratory exchange ratio in response to the 3 min stage duration was significantly lower than the 5 min duration (0.83 ± 0.05 vs. 0.86 ± 0.03, p = 0.04, Cohen's d = 0.76). Results suggest that a 3 min stage duration is preferred to assess substrate metabolism during upper-body exercise in healthy adults.

Partial Pressure of End-Tidal Oxygen and Blood Lactate During Cardiopulmonary Exercise Testing in Healthy Older Participants and Patients at Risk of Cardiac Disease.

Background: The partial pressure of end-tidal oxygen (PETO2) and end-tidal oxygen concentration (ETO2) are among the indices that can be measured by exhaled gas analysis. Several observational studies have shown that skeletal muscle function is impaired in patients with cardiac disease; thus, the assessment of skeletal muscle function is important. Additionally, although it has recently been suggested that the difference in PETO2 from rest to the ventilatory anaerobic threshold (VAT) reflects oxygen availability in peripheral factors, primarily skeletal muscle, the evidence for this is not well established. Therefore, we hypothesized and investigated whether increased blood lactate (BLa) levels, resulting from decreased skeletal muscle and mitochondrial oxygen availability, and PETO2 dynamics during cardiopulmonary exercise testing (CPET) would be related. Methods: All participants performed the symptomatic limited CPET, and their BLa levels were measured. The difference in PETO2 and ETO2 from rest to VAT determined by the V-slope method (ΔPETO2 and ΔETO2) was calculated and compared with the increase in BLa due to exercise testing. Results: We recruited 22 healthy older participants (nine males; 69.4 ± 6.8 years) and 11 patients with cardiovascular risk (eight males; 73.0 ± 8.8 years). ΔPETO2 and ΔETO2 did not differ between the two groups (P = 0.355 and P = 0.369, respectively), showing no correlation between increase in BLa from rest to VAT, but were significantly correlated with an increase in BLa from rest to the end of exercise (ΔPETO2, P = 0.030; ΔETO2, P = 0.029). The correlation was particularly pronounced among those at cardiovascular risk (ΔPETO2, P = 0.012; ΔETO2, P = 0.011). Conclusions: ΔPETO2 and ΔETO2 from rest to VAT during CPET may be useful as indices reflecting skeletal muscle oxygen utilization capacity.

Influence of blood lactate variations and passive exercise on cardiac responses.

[Purpose] This study aimed to investigate cardiovascular responses, including heart rate (HR) and heart rate variability (HRV), to various hyperlactatemia-passive exercise interactions. [Participants and Methods] Nine healthy male participants performed upper limb passive cycling movement, and their HR and HRV were assessed while their blood lactate levels were manipulated by sustained handgrip exercise at control, 15% maximum voluntary contraction (MVC), and 30% MVC, followed by postexercise circulatory occlusion. [Results] HR and root mean squared standard difference (rMSSD) of HRV response remained constant at all blood lactate levels during passive exercise (HR: control, 75.8 ± 3.4 bpm; 15% MVC, 76.9 ± 2.7 bpm; and 30% MVC, 77.0 ± 3.7 bpm; rMSSD: control, 33.2 ± 6.9 ms; 15% MVC, 36.3 ± 7.3 ms; and 30% MVC, 37.3 ± 8.9 ms). [Conclusion] Manipulating metaboreflex activation did not significantly alter HR or HRV during passive exercise. These results suggest that, in healthy participants, the interactions between mechanical and metabolic stimuli do not affect HR and HRV responses, implying that passive exercise may be safely implemented.

Effect of the Fran CrossFit Workout on Oxygen Uptake Kinetics, Energetics, and Postexercise Muscle Function in Trained CrossFitters.

PURPOSE: Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters' improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters' training performance improvements. The aim of the study was to analyze the oxygen uptake (V˙O2) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran. METHODS: Twenty trained CrossFitters performed Fran at maximal exertion. V˙O2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period. RESULTS: A marked increase in V˙O2 kinetics was observed at the beginning of Fran, remaining elevated until the end (V˙O2peak: 49.2 [3.7] mL·kg-1·min-1, V˙O2 amplitude: 35.8 [5.2] mL·kg-1·min-1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period. CONCLUSIONS: The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue.

Analysis of Course of Changes in Blood Lactate Concentration in Response to Graded Exercise Test and Modified Wingate Test in Adolescent Road Cyclists.

BACKGROUND: The purpose of this study was to analyze the course of changes in the blood lactate (BL) concentration in response to the graded exercise test (GXT) and the modified Wingate test (MWT). METHODS: This study involved 23 male highly trained road cyclists (age: 16.2 ± 1.1 years; experience: 5.0 ± 2.1 years; VO2max 59.0 ± 3.5 mL × kg-1 × min-1). The analysis of BL concentration was conducted using an enzymatic-amperometric electrochemical technique. RESULTS: Our study provided the following information: (i) peak BL concentration in response to GXT (12.86 ± 2.32 mmol × L-1) and MWT (12.85 ± 1.47 mmol × L-1) is expected around the third minute after the completion of the trial; (ii) 60 min is not a sufficient period for BL concentration to return to resting values after GXT; (iii) post-GXT BL removal during the 60 min period is unsteady (3-20 min: -2.6 ± -0.6% × min-1; 20-60 min: -1.6 ± -0.3% × min-1; p-value for comparison < 0.01), whereas post-MWT BL removal during the 12 min period appears to be constant (3-6 min: -2.4 ± -5.6% × min-1, 6-9 min: -2.6 ± -1.8 % × min-1; 9-12 min: -3.1 ± -2.1 % × min-1; p-value for all comparisons < 0.01). CONCLUSIONS: When aiming to obtain valuable data regarding the course of changes in BL concentration during the post-exertion period, it is essential to consider the number of measurements and the time points in sample collection for analysis.

Effects of carbohydrate availability on cycling endurance at the maximal lactate steady state.

The impacts of carbohydrate (CHO) availability on time to task failure (TTF) and physiological responses to exercise at the maximal lactate steady state (MLSS) have not been studied. Ten participants (3 females, 7 males) completed this double-blinded, placebo-controlled study that involved a ramp incremental test, MLSS determination, and four TTF trials at MLSS, all performed on a cycle ergometer. With the use of a combination of nutritional (CHO, 7 g/kg, and placebo, PLA, 0 g/kg drinks) and exercise interventions [no exercise (REST) and glycogen-reducing exercise (EX)], the four conditions were expected to differ in preexercise CHO availability (RESTCHO > RESTPLA > EXCHO > EXPLA). TTF at MLSS was not improved by CHO loading, as RESTCHO (57.1 [16.6] min) and RESTPLA (57.1 [15.6] min) were not different (P = 1.00); however, TTF was ∼50% shorter in EX conditions compared with REST conditions on average (P < 0.05), with EXCHO (39.1 [9.2] min) ∼90% longer than EXPLA (20.6 [6.9] min; P < 0.001). There were effects of condition for all perceptual and cardiometabolic variables when compared at isotime (P < 0.05) and task failure (TF; P < 0.05), except for ventilation, perceptual responses, and neuromuscular function measures, which were not different at TF (P > 0.05). Blood lactate concentration was stable in all conditions for participants who completed 30 min of exercise. These findings indicate that TTF at MLSS is not enhanced by preexercise CHO supplementation, but recent intense exercise decreases TTF at MLSS even with CHO supplementation. Extreme fluctuations in diet and strenuous exercise that reduce CHO availability should be avoided before MLSS determination.NEW & NOTEWORTHY Carbohydrate (CHO) loading did not increase participants' ability to cycle at their maximal lactate steady state (MLSS); however, performing a glycogen depletion task the evening before cycling at MLSS reduced the time to task failure, even when paired with a high dose of CHO. These diet and exercise interventions influenced blood lactate concentration ([BLa]) but not the stability of [BLa]. Activities that reduce CHO availability should be avoided before MLSS determination.

Energetics of sinusoidal exercise below and across critical power and the effects of fatigue.

PURPOSE: Previous studies investigating sinusoidal exercise were not devoted to an analysis of its energetics and of the effects of fatigue. We aimed to determine the contribution of aerobic and anaerobic lactic metabolism to the energy balance and investigate the fatigue effects on the cardiorespiratory and metabolic responses to sinusoidal protocols, across and below critical power (CP). METHODS: Eight males (26.6 ± 6.2 years; 75.6 ± 8.7 kg; maximum oxygen uptake 52.8 ± 7.9 ml·min-1·kg-1; CP 218 ± 13 W) underwent exhausting sinusoidal cycloergometric exercises, with sinusoid midpoint (MP) at CP (CPex) and 50 W below CP (CP-50ex). Sinusoid amplitude (AMP) and period were 50 W and 4 min, respectively. MP, AMP, and time-delay (tD) between mechanical and metabolic signals of expiratory ventilation ( V ˙ E ), oxygen uptake ( V ˙ O 2 ), and heart rate ( f H ) were assessed sinusoid-by-sinusoid. Blood lactate ([La-]) and rate of perceived exertion (RPE) were determined at each sinusoid. RESULTS: V ˙ O 2 AMP was 304 ± 11 and 488 ± 36 ml·min-1 in CPex and CP-50ex, respectively. Asymmetries between rising and declining sinusoid phases occurred in CPex (36.1 ± 7.7 vs. 41.4 ± 9.7 s for V ˙ O 2 tD up and tD down, respectively; P < 0.01), with unchanged tDs. V ˙ O 2 MP and RPE increased progressively during CPex. [La-] increased by 2.1 mM in CPex but remained stable during CP-50ex. Anaerobic contribution was larger in CPex than CP-50ex. CONCLUSION: The lower aerobic component during CPex than CP-50ex associated with lactate accumulation explained lower V ˙ O 2 AMP in CPex. The asymmetries in CPex suggest progressive decline of muscle phosphocreatine concentration, leading to fatigue, as witnessed by RPE.

Effects of a 16-Week Training Program with a Pyramidal Intensity Distribution on Recreational Male Cyclists.

Different training intensity distributions (TIDs) have been proposed to improve cycling performance, especially for high-competition athletes. The objectives of this study were to analyze the effect of a 16-week pyramidal training intensity distribution on somatic and power variables in recreational cyclists and to explore the training zone with the greatest impact on performance improvement. The sample consisted of 14 male recreational cyclists aged 41.00 ± 7.29 years of age. A number of somatic variables were measured. During an incremental protocol, power at a 4 mMol·L-1 blood lactate concentration (P4), corresponding power to body mass ratio (P/W P4), and heart rate (HR P4) were also measured. Among the somatic variables, the percentage of fat mass showed the greatest improvement between moments (p < 0.001, d = 0.52). Both P4 (p < 0.001, d = 1.21) and P/W P4 (p < 0.001, d = 1.54) presented a significant increase between moments. The relative improvement in P4 (% P4) showed a significant correlation (Rs = 0.661, p = 0.038) and relationship (R2 = 0.61, p = 0.008) mainly with training zone Z2 (blood lactate levels ≥ 2 and <4 mMol·L-1). It seems that spending more time in Z2 promoted an improvement in both somatic and power variables in recreational cyclists.

Subtetanic neuromuscular electrical stimulation can maintain Wingate test performance but augment blood lactate accumulation.

PURPOSE: Concentration- and time-dependent effect of lactate on physiological adaptation (i.e., glycolytic adaptation and mitochondrial biogenesis) have been reported. Subtetanic neuromuscular electrical stimulation (NMES) with voluntary exercise (VOLES) can increase blood lactate accumulation. However, whether this is also true that VOLES can enhance the blood lactate accumulation during sprint exercise is unknown. Thus, we investigated whether VOLES before the Wingate test can enhance blood lactate accumulation without compromising Wingate exercise performance. METHODS: Fifteen healthy young males (mean [SD], age: 23 [4] years, body mass index: 22.0 [2.1] kg/m2) volunteered. After resting measurement, participants performed a 3-min intervention: VOLES (NMES with free-weight cycling) or voluntary cycling alone, which matched exercise intensity with VOLES (VOL, 43.6 [8.0] watt). Then, they performed the Wingate test with 30 min free-weight cycling recovery. The blood lactate concentration ([La]b) was assessed at the end of resting and intervention, and recovery at 1, 3, 5, 10, 20, and 30 min. RESULTS: [La]b during intervention was higher with VOLES than VOL (P = 0.011). The increase in [La]b after the Wingate test was maintained for longer with VOLES than VOL at 10- and 20-min recovery (P = 0.014 and 0.023, respectively). Based on the Wingate test, peak power, mean power, and the rate of decline were not significantly different between VOLES and VOL (P = 0.184, 0.201, and 0.483, respectively). CONCLUSION: The combination of subtetanic NMES with voluntary exercise before the Wingate test has the potential to enhance blood lactate accumulation. Importantly, this combined approach does not compromise Wingate exercise performance compared to voluntary exercise alone.