Relationship between anaerobic capacity estimated using a single effort and 30-s tethered running outcomes

Reliability of Anaerobic Contributions during a Single Exhaustive Knee-extensor Exercise

The total anaerobic contribution (AC[La-]+PCr) is a valid and reliable methodology. However, the active muscle mass plays an important role in the AC[La-]+PCr determination, which might influence its reliability. Thus, this study aimed to investigate the effects of two exhaustive intensities on the reliability of the AC[La-]+PCr during a one-legged knee extension (1L-KE) exercise. Thirteen physically active males were submitted to a graded exercise to determine the peak power output (PPO) in the 1L-KE. Then, two constant-load exercises were conducted to task failure at 100% (TTF100) and 110% (TTF110) of PPO, and the exercises were repeated on a third day. The blood lactate accumulation and the oxygen uptake after exercise were used to estimate the anaerobic lactic and alactic contributions, respectively. Higher values of AC[La-]+PCr were found after the TTF100 compared to TTF110 (p=0.042). In addition, no significant differences (p=0.432), low systematic error (80.9 mL), and a significant ICC (0.71; p=0.004) were found for AC[La-]+PCr in the TTF100. However, an elevated coefficient of variation was found (13.7%). In conclusion, we suggest the use of the exhaustive efforts performed at 100% of the PPO with the 1L-KE model, but its elevated individual variability must be carefully considered in future studies.

Mechanical energy on anaerobic capacity during a supramaximal treadmill running in men: Is there influence between runners and active individuals?

This study verified whether mechanical variables influence the anaerobic capacity outcome on treadmill running and whether these likely influences were dependent of running experience. Seventeen physical active and 18 amateur runners, males, performed a graded exercise test and constant load exhaustive running efforts at 115% of intensity associated to maximal oxygen consumption. During the constant load were determined the metabolic responses (i.e., gas exchange and blood lactate) to estimate the energetic contribution and anaerobic capacity as well as kinematic responses. The runners showed higher anaerobic capacity (16.6%; p = 0.005), but lesser time to exercise failure (-18.8%; p = 0.03) than active subjects. In addition, the stride length (21.4%; p = 0.00001), contact phase duration (-11.3%; p = 0.005), and vertical work (-29.9%; p = 0.015). For actives, the anaerobic capacity did not correlate significantly with any physiologic, kinematic, and mechanical variables and no regression model was fitted using the stepwise multiple regression, while to runners the anaerobic capacity was significantly correlated with phosphagen energetic contribution (r = 0.47; p = 0.047), external power (r = -0.51; p = 0.031), total work (r = -0.54; p = 0.020), external work (r = -0.62; p = 0.006), vertical work (r = -0.63; p = 0.008), and horizontal work (r = -0.61; p = 0.008), and the vertical work and phosphagen energetic contribution presented a coefficient of determination of 62% (p = 0.001). Based on findings, it is possible to assume that for active subjects, the mechanical variables have no influence over the anaerobic capacity, however, for experienced runners, the vertical work and phosphagen energetic contribution have relevant effect over anaerobic capacity output.

Effects of different inspiratory muscle warm-up loads on mechanical, physiological and muscle oxygenation responses during high-intensity running and recovery

Inspiratory muscle warm-up (IMW) has been used as a resource to enhance exercises and sports performance. However, there is a lack of studies in the literature addressing the effects of different IMW loads (especially in combination with a shorter and applicable protocol) on high-intensity running and recovery phase. Thus, this study aimed to investigate the effects of three different IMW loads using a shorter protocol on mechanical, physiological and muscle oxygenation responses during and after high-intensity running exercise. Sixteen physically active men, randomly performed four trials 30 s all-out run, preceded by the shorter IMW protocol (2 × 15 breaths with a 1-min rest interval between sets, accomplished 2 min before the 30 s all-out run). Here, three IMW load conditions were used: 15%, 40%, and 60% of maximal inspiratory pressure (MIP), plus a control session (CON) without the IMW. The force, velocity and running power were measured (1000 Hz). Two near-infrared spectroscopy (NIRS) devices measured (10 Hz) the muscle’s oxygenation responses in biceps brachii (BB) and vastus lateralis (VL). Additionally, heart rate (HR) and blood lactate ([Lac]) were also monitored. IMW loads applied with a shorter protocol promoted a significant increase in mean and minimum running power as well as in peak and minimum force compared to CON. In addition, specific IMW loads led to higher values of peak power, mean velocity (60% of MIP) and mean force (40 and 60% of MIP) in relation to CON. Physiological responses (HR and muscles oxygenation) were not modified by any IMW during exercise, as well as HR and [Lac] in the recovery phase. On the other hand, 40% of MIP presented a higher tissue saturation index (TSI) for BB during recovery phase. In conclusion, the use of different loads of IMW may improve the performance of a physically active individual in a 30 s all-out run, as verified by the increased peak, mean and minimum mechanical values, but not in performance assessed second by second. In addition, 40% of the MIP improves TSI of the BB during the recovery phase, which can indicate greater availability of O₂ for lactate clearance.

Effects of short-term betaine supplementation on muscle endurance and indices of endocrine function following acute high-intensity resistance exercise in young athletes

Objective

This study examined the effects of short-term betaine supplementation on muscle endurance, plasma lactate, testosterone and cortisol levels, and the testosterone to cortisol (T/C) ratio in response to acute resistance exercise (RE).

Method

Using a double-blind, crossover study design, 10 handball players (age ± SD = 16 ± 1 yrs) without prior-structured RE experience performed a high-intensity RE session (leg press followed by bench press; 5 sets to volitional fatigue using 80% baseline 1 repetition maximum (1RM)), before and after 14 days of either placebo (maltodextrin) or betaine (2.5 g·d⁻¹) supplementation. A 30-day washout period separated each treatment. 48 h prior to testing sessions, participants recorded their food intake and did not perform strenuous exercise. Venous blood was sampled before supplementation, and before and after each RE session.

Results

After betaine supplementation, participants performed more repetitions (p < 0.001) during the leg press (Betaine: 35.8 ± 4.3; Placebo: 24.8 ± 3.6, Cohen’s d = 2.77) and bench press (Betaine: 36.3 ± 2.6; Placebo: 26.1 ± 3.5, Cohen’s d = 3.34). Betaine resulted in lower post-exercise cortisol (Betaine: 7.6 ± 1.7; Placebo: 13 ± 3.4 µg.dL⁻¹, p = 0.003, generalized eta squared (ηG2) = 0.49) and lactate (Betaine: 5.2 ± 0.3; Placebo: 6 ± 0.3 mmol.L⁻¹, p < 0.001, ηG2 = 0.96) and higher total testosterone (Betaine: 15.2 ± 2.2; Placebo: 8.7 ± 1.7 ng.mL⁻¹, p < 0.001, ηG2 = 0.87) and T/C ratio (Betaine: 0.21 ± 0.05; Placebo: 0.07 ± 0.02, p < 0.001, = 0.82).

Conclusions

Two weeks of betaine supplementation improved upper- and lower-body muscle endurance and influenced indices of endocrine function following an acute session of high-intensity RE in adolescent handball players.

Anaerobic Capacity is Associated with Metabolic Contribution and Mechanical Output Measured During the Wingate Test

The study aimed to investigate the relationship between anaerobic capacity, mechanical and anaerobic contribution during the 30-s Wingate Anaerobic Test (30sWAnT). After familiarization, fifteen, male recreational mountain biking practitioners underwent the following sequence of tests: 1) a graded exercise test to determine maximal oxygen uptake and associated intensity i V ˙ O 2 m a x ; 2 and 3) supramaximal exhaustive effort at 115% of iVO_2max and 30sWAnT, performed randomly. The glycolytic and phosphagen pathways measured during the supramaximal effort were significantly correlated with peak power (r = 0.85; p < 0.01 and r = 0.57; p = 0.02, respectively), mean power (r = 0.78; p < 0.01 and r = 0.69; p < 0.01, respectively), and total work (r = 0.78; p < 0.01 and r = 0.69; p< 0.02, respectively) measured during the 30sWAnT. A significant correlation was also found between anaerobic capacity and peak power (r = 0.88; p < 0.01), mean power (r = 0.89; p < 0.01), and total work (r = 0.89; p < 0.01). Additionally, anaerobic capacity estimated during the supramaximal effort and the anaerobic contribution measured during the 30sWAnT were not different (p = 0.44) and presented significant good reliability and association (ICC = 0.84; p = 0.001) and good agreement, evidenced by the mean of differences and 95% limits of agreement near to zero (mean bias = 0.11). The results suggest that glycolytic and phosphagen capacity were associated with mechanical performance in the 30sWAnT. In addition, anaerobic contribution during the 30sWAnT seems to be valid for estimating anaerobic capacity in recreational mountain bike cyclists, as well as to estimate the glycolytic and phosphagen contributions.

Reliability and Validity of a New Portable Tethered Sprint Running Test as a Measure of Maximal Anaerobic Performance

Limmer, M, Berkholz, A, de Marées, M, and Platen, P. Reliability and validity of a new portable tethered sprint running test as a measure of maximal anaerobic performance. J Strength Cond Res 34(8): 2197-2204, 2020-The purposes of this study were to develop a new portable tethered sprint running (PTSR) test for field-based anaerobic performance testing with restricted spatial conditions and the logistical challenge of carrying test equipment, and to determine reliability of the PTSR test. For validity, performance measures were compared with the cycle ergometer Wingate Anaerobic Test (WAnT) power outputs. Twelve recreationally active men and women (24.3 ± 1.6 years; 1.77 ± 0.07 m; 73.3 ± 12.5 kg) performed one familiarization trial followed by 3 randomly assigned experimental 60-second all-out effort trials consisting of one WAnT and 2 PTSR tests. All trials were performed in a randomized order on different days separated by at least 48 hours. Heart rate (HR) and maximum blood lactate concentration were recorded for each experimental trial to determine the physiological responses to the maximal efforts. Correlation coefficients indicated significant relationships between mean force (MF) and peak force (PF) in the PTSR test and mean power (MP) (r = 0.651, p = 0.022) and peak power (PP) (r = 0.877, p = 0.002) in the WAnT, but not for the fatigue index (r = 0.280, p = 0.379). In addition, both PTSR trials showed no significant differences (p > 0.05) between trials and a high reliability for the performance variables MF (intraclass correlation coefficient [ICC] = 0.98, coefficient of variation [%CV] = 7.7), PF (ICC = 0.98, %CV = 8.4), and HR (ICC = 0.92, %CV = 3.1). In conclusion, our results suggest that despite insufficient stimulation of anaerobic metabolism in some subjects resulting from poor implementation of test instructions, the PTSR is a reliable and valid test for an easy and practical assessment of maximal anaerobic performance under different field conditions.

Cardiorespiratory strain during stroke rehabilitation: Are patients trained enough? A systematic review

BACKGROUND

Rehabilitation is a mandatory component of stroke management, aiming to recover functional capacity and independence. To that end, physical therapy sessions must involve adequate intensity in terms of cardiopulmonary stress to meet the physiological demands of independent living.

OBJECTIVE

The aim of this systematic review was to determine the current level of cardiopulmonary strain during rehabilitation sessions in stroke patients.

METHODS

Three electronic databases (PubMed, CINAHL and Embase. com) were searched to identify observational studies that documented cardiopulmonary strain during rehabilitation sessions in post-stroke patients (last search performed in February 2019). A manual cross-referencing search was also performed. To be included, articles needed to report data related to both cardiopulmonary strain (heart rate, oxygen consumption or energy expenditure) and active therapy time. The methodological quality of each study was assessed with the Evidence-Based Librarianship Critical Appraisal Tool. Data related to both cardiorespiratory strain and active therapy time were extracted from selected articles.

RESULTS

Four of 43 full-text articles assessed for eligibility met the inclusion criteria. Results extracted from these articles suggested that the intensity of rehabilitation sessions was insufficient to induce a cardiopulmonary training effect in a post-stroke context as measured by metabolic stress. Patients were inactive from 21% to 80% of the therapy time. The Evidence-Based Librarianship tool scores ranged from 65% (15/23) to 91% (21/23), which indicates questionable to good quality.

CONCLUSION

The current literature on cardiopulmonary solicitation during stroke rehabilitation sessions is poor in terms of both the number of studies available and their methodological quality. Summarized results tend to support previous claims that rehabilitation sessions offered to stroke patients are of suboptimal cardiopulmonary strain, which can interfere with their capacity to regain functional independence.

Corresponding Assessment Scenarios in Laboratory and on-Court Tests: Centrality Measurements by Complex Networks Analysis in Young Basketball Players

Besides technical and tactical aspects, basketball matches involve high aerobic and anaerobic capacities, conferring the final performance of a team. Thus, the evaluation of physical and technical responses is an effective way to predict the performance of athletes. Field and laboratory tests have been used in sports. The first involving high ecological validity and low cost, and the second, greater control and accuracy but not easy application, considering the different preparation phases in a season. This study aimed, through complex networks analysis, to verify whether centrality parameters analysed from significant correlations behave similarly in distinct scenarios (laboratory and on-court), emphasizing aerobic and anaerobic physical parameters and technical performances. The results showed that, in a compelling  analysis involving basketball athletes, the studied centralities (degree, betweenness, eigenvector and pagerank) revealed similar responses in both scenarios, which is widely attractive considering the greater financial economy and lower time when applying tests in the field.

New Insights into Mechanical, Metabolic and Muscle Oxygenation Signals During and After High-Intensity Tethered Running

High-intensity exercises including tethered efforts are commonly used in training programs for athletes, active and even sedentary individuals. Despite this, the knowledge about the external and internal load during and after this effort is scarce. Our study aimed to characterize the kinetics of mechanical and physiological responses in all-out 30 seconds (AO30) tethered running and up to 18 minutes of passive recovery. Additionally, in an innovative way, we investigated the muscle oxygenation in more or less active muscles (vastus lateralis and biceps brachii, respectively) during and after high-intensity tethered running by near-infrared spectroscopy – NIRS. Twelve physically active young men were submitted to AO30 on a non-motorized treadmill to determine the running force, velocity and power. We used wearable technologies to monitor the muscle oxygenation and heart rate responses during rest, exercise and passive recovery. Blood lactate concentration and arterial oxygen saturation were also measured. In a synchronized analysis by high capture frequency of mechanical and physiological signals, we advance the understanding of AO30 tethered running. Muscle oxygenation responses showed rapid adjustments (both, during and after AO30) in a tissue-dependence manner, with very low tissue saturation index observed in biceps brachii during exercise when compared to vastus lateralis. Significant correlations between peak and mean blood lactate with biceps brachii oxygenation indicate an important participation of less active muscle during and after high-intensity AO30 tethered running.

Creatine Supplementation Improves Phosphagen Energy Pathway During Supramaximal Effort, but Does Not Improve Anaerobic Capacity or Performance

This study aimed to investigate the effects of short-duration creatine monohydrate supplementation on anaerobic capacity (AC), anaerobic energy pathways, and time-to-exhaustion during high-intensity running. Fourteen healthy men underwent a graded exercise test (GXT) followed by a O_2max confirmation test, 5 submaximal efforts, and 4 supramaximal running bouts at 115% of V˙O_2max intensity (the first two supramaximal sessions were applied as familiarization trials) to measure the AC using two procedures; the maximum accumulated oxygen deficit (MAOD) and non-oxidative pathways energetics sum (AC_{[La-]+EPOCfast}). The investigation was conducted in a single-blind and placebo-controlled manner, with participants performing the efforts first after being supplemented with a placebo (dextrose 20 g⋅day^-1 for 5 days), and then, after a 7 day “placebo” washout period, they started the same procedure under creatine supplementation (20 g⋅day^-1 for 5 days. This order was chosen due to the prolonged washout of creatine. MAOD was not different between placebo (3.35 ± 0.65 L) and creatine conditions (3.39 ± 0.79 L; P = 0.58) and presented a negligible effect [effect size (ES) = 0.08], similar to, AC_{[La-]+EPOCfast} (placebo condition (3.66 ± 0.79 Land under creatine ingestion 3.82 ± 0.85 L; P = 0.07) presenting a small effect (ES = 0.20). The energetics from the phosphagen pathway increased significantly after creatine supplementation (1.66 ± 0.40 L) compared to the placebo condition (1.55 ± 0.42 L; P = 0.03). However, the glycolytic and oxidative pathways were not different between conditions. Furthermore, time to exhaustion did not differ between placebo (160.79 ± 37.76 s) and creatine conditions (163.64 ± 38.72; P = 0.49). Therefore, we can conclude that creatine supplementation improves the phosphagen energy contribution, but with no statistical effect on AC or time to exhaustion in supramaximal running.

Anaerobic capacity estimated by the sum of both oxygen equivalents from the glycolytic and phosphagen pathways is dependent on exercise mode: Running versus cycling

The purpose of this study was to verify whether the exercise modality (i.e., running and cycling) alters the magnitude of “anaerobic” capacity estimated by a single supramaximal effort (AC_{[La]+EPOCfast}). Fourteen healthy men (age: 26±9 years) underwent a maximum incremental test and a supramaximal effort to exhaustion at 115% of the intensity associated with maximal oxygen uptake to determine the AC_{[La]+EPOCfast} (i.e., the sum of both oxygen equivalents from the glycolytic and phosphagen pathways), performed on both a treadmill and cycle ergometer. The maximal oxygen uptake during running was higher (p = 0.001; large effect size) vs. cycling (48.9±3.9mL·kg^-1·min^-1 vs. 44.8±5.5mL·kg^-1·min^-1 respectively). Contrarily, the oxygen equivalent from the glycolytic metabolism was not different between exercise modalities (p = 0.133; small effect size; running = 2.35±0.48 L and cycling = 2.18±0.58 L). Furthermore, the “anaerobic” capacity was likely meaning fully (3.65±0.70 L) and very likely meaningfully (949.1±5.7 mL·kg^-1) greater in running than cycling (3.81±0.71 L and 52.0±8.1 mL·kg^-1). Additionally, the contribution of the phosphagen metabolism was higher (p = 0.001; large effect size) for running compared to cycling (1.6±0.3 L vs.1.3±0.3 L respectively). Therefore, the “anaerobic” capacity estimated by the sum of both oxygen equivalents from the glycolytic and phosphagen pathways during a supramaximal effort is influenced by exercise modality and is able to identify the difference in phosphagen metabolic contribution, based on the methodological conditions of this study.

Validity and Reliability of the 30-s Continuous Jump for Anaerobic Power and Capacity Assessment in Combat Sport

Cycling test such Wingate anaerobic test (WAnT) is used to measure anaerobic power (AP), but not anaerobic capacity (AC, i.e., the metabolic energy demand). However, in sports that do not involve cycling movements (Karate), the continuous jump for 30 s (vertical jumps for 30 s) has been extensively used to measure anaerobic performance in all young athletes. Limited information’s are available concerning its validity and reliability especially in children. As such, the current study aimed to test validity and reliability of a continuous jumps test (the CJ30s), using WAnT as a reference. Thirteen female Karate kids (age: 11.07 ± 1.32 years; mass: 41.76 ± 15.32 kg; height: 152 ± 11.52 cm; training experience: 4.38 ± 2.14 years) were tested on three separate sessions. The first and second sessions were used to assess the reliability using Intra-class correlation coefficient (ICC) of CJ30s, whereas on the third session WAnT was administered. Following CJ30s and WAnT, we assessed AP (1/CJ30s, as jump height [JH], fatigue index [FI], and blood lactate [BL]; 2/WAnT, as mechanical power [P], FI, and BL) and AC as the excess post-exercise oxygen consumption (EPOC). Large/highly significant correlations were found between CJ30s and WAnT EPOCs (r = 0.730, P = 0.003), and BLs (r = 0.713, P = 0.009). Moderate/significant correlations were found between CJ30s and WAnT FIs (r = 0.640, P = 0.014), CJ30s first four jumps mean JH and WAnT peak P (r = 0.572, P = 0.032), and CJ30s mean JH and WAnT mean P (r = 0.589, P = 0.021). CJ30s showed excellent and moderate reliability (ICC) for AP (maximal JH 0.884, mean JH 0.742, FI 0.657, BL 0.653) and AC (EPOC 0.788), respectively. Correlations observed especially in terms of AC between CJ30s and WAnT provide evidence that former may adequately assess anaerobic performance for the young combat athlete. CJ30 is a reliable test and allow an easy assessment of AP and AC in karate children.

The 3-min all-out test is valid for determining critical power but not anaerobic work capacity in tethered running

The purpose of the study was to investigate if the 3-min all-out test (3MT) is valid for obtaining critical power intensity (CP) and the amount of work that can be performed above CP (W’) on non-motorized treadmills in tethered running. Eight physically active individuals (24 ± 3 years; 78.3 ± 8.7 kg; 179 ± 5 cm; 9.0 ± 2.5% body fat) performed four different efforts at constant intensity to exhaustion in order to determine CP and W’. The mechanical power values obtained were subsequently plotted with their corresponding time to exhaustion (limit time) for application of three mathematical models: power hyperbolic versus time limit (Hyp), linear power versus 1/time (P vs 1/t) and linear work versus time limit (Ԏ vs t). The 3MT test was carried out on the last day to determine end power (EP) and anaerobic capacity (WEP) using this methodology. EP value of 181.7 ± 52 was similar (p = 0.486) to 178.2 ± 61 (CP Hyp), 191.4 ± 55 (Ԏ vs t) and 188.3 ± 55 (P vs 1/t). WEP value of 17.9 ± 4.8 was not similar (p = 0.000) to 50.2 ± 15.3 (CP Hyp), 44.8 ± 8.7 (Ԏ vs t) and 45.5 ± 8.4 (P vs 1/t). Positive results (r = 0.78–0.98 and ICC = 0.88–0.99) of Pearson correlation and intraclass correlation (ICC–absolute agreement) were found for aerobic applications of conventional CP and 3MT. For anaerobic data, only the three models of conventional CP were correlated (r = 0.76–0.93); however, W’ from the three models was not correlated with WEP (r = 0.37–0.52). The results of this study suggest that 3MT in tethered running on non-motorized treadmills is a valid test for estimating CP aerobic parameters in a single day of application but not anaerobic parameters of W’.

Anaerobic metabolism during short all-out efforts in tethered running: Comparison of energy expenditure and mechanical parameters between different sprint durations for testing

This study's aims to verify the energy expenditure, metabolic distress and usefulness to evaluate the anaerobic constructs for different all-out durations in running efforts. Twelve active male underwent four testing sessions, one for familiarization and three performing one all-out (AO) tethered running sprint lasting 30s, 20s or 10s. Oxygen consumption, excess post exercise oxygen consumption, and lactate production were retained to analyse metabolic function, together with mechanical power and work as performance parameters. Paired results were compared via one-way ANOVA for repeated measures (Tukey-HSD post-hoc), effect sizes and ICC for absolute agreement. Statistical significance was accepted at p ≤ 0.05. Despite total and energy expenditure from oxidative pathway being significantly higher for longer durations (p < 0.001; ES > 0.7), glycolytic energy expenditure presented an agreement between AO30s and AO20s (ICC-A = 0.63*), while the paired comparisons to AO10s have presented significant differences (p < 0.01; ES > 1.0). Phosphagen energy expenditure were similar between all-out durations (p = 0.12; ICC-A = 0.62*; ES < 0.5). Maximum mechanical power was higher in AO10s than in AO30s (p = 0.03; ES = 0.6), not being different between AO10s and AO20s (p = 0.67; ICC-A = 0.88*; ES = 0.2) and between AO20s and AO30s (p = 0.18; ICC-A = 0.56*; ES = 0.4). In addition, agreement between work in the first ten seconds was confirmed via ICC only between AO10s and AO20s (p = 0.50; ICC-A = 0.86*; ES = 0.3), but not for the other paired comparisons (p < 0.1; ICC < 0.45; ES > 0.5). AO20s is a better alternative to estimate anaerobic power and capacity in one single test, with similar oxidative demand than AO30s.