Use of loaded conditioning activities to potentiate middle- and long-distance performance: a narrative review and practical applications

The warm-up is an integral component of a middle- and long-distance athlete’s pre-performance routine. The use of a loaded conditioning activity (LCA), which elicits a post-activation potentiation (PAP) response to acutely enhance explosive power performance, is well-researched. A similar approach incorporated into the warm-up of a middle- or long-distance athlete potentially provides a novel strategy to augment performance. Mechanisms that underpin a PAP response, relating to acute adjustments within the neuromuscular system, should theoretically improve middle- and long-distance performance via improvements in sub-maximal force-generating ability. Attempts to enhance middle- and long-distance related outcomes using a LCA have been used in several recent studies. Results suggest benefits to performance may exist in well-trained middle- and long-distance athletes by including high-intensity resistance training (1-5 repetition maximum) or adding load to the sport skill itself during the latter part of warm-ups. Early stages of performance appear to benefit most, and it is likely that recovery (5-10 min) also plays an important role following a LCA. Future research should consider how priming activity, designed to enhance the V[Combining Dot Above]O2 kinetic response, and a LCA may interact to affect performance, and how different LCA’s might benefit various modes and durations of middle- and long-distance exercise

Effects of strength training on the physiological determinants of middle- and long-distance running performance: a systematic review

Background: Middle- and long-distance running performance is constrained by several important aerobic and anaerobic parameters. The efficacy of strength training (ST) for distance runners has received considerable attention in the literature. However, to date, the results of these studies have not been fully synthesized in a review on the topic. Objectives: This systematic review aimed to provide a comprehensive critical commentary on the current literature that has examined the effects of ST modalities on the physiological determinants and performance of middle- and long-distance runners, and offer recommendations for best practice. Methods: Electronic databases were searched using a variety of key words relating to ST exercise and distance running. This search was supplemented with citation tracking. To be eligible for inclusion, a study was required to meet the following criteria: participants were middle- or long-distance runners with ≥ 6 months experience, a ST intervention (heavy resistance training, explosive resistance training, or plyometric training) lasting ≥ 4 weeks was applied, a running only control group was used, data on one or more physiological variables was reported. Two independent assessors deemed that 24 studies fully met the criteria for inclusion. Methodological rigor was assessed for each study using the PEDro scale. Results: PEDro scores revealed internal validity of 4, 5, or 6 for the studies reviewed. Running economy (RE) was measured in 20 of the studies and generally showed improvements (2–8%) compared to a control group, although this was not always the case. Time trial (TT) performance (1.5–10 km) and anaerobic speed qualities also tended to improve following ST. Other parameters [maximal oxygen uptake (V˙ O 2 max), velocity at V˙ O 2 max, blood lactate, body composition] were typically unaffected by ST. Conclusion: Whilst there was good evidence that ST improves RE, TT, and sprint performance, this was not a consistent finding across all works that were reviewed. Several important methodological differences and limitations are highlighted, which may explain the discrepancies in findings and should be considered in future investigations in this area. Importantly for the distance runner, measures relating to body composition are not negatively impacted by a ST intervention. The addition of two to three ST sessions per week, which include a variety of ST modalities are likely to provide benefits to the performance of middle- and long-distance runners

Quantification of aerobic determinants of performance in post-pubertal adolescent middle-distance runners

PURPOSE: The use of oxygen cost ([Formula: see text]aero) parameters to predict endurance performance has recently been criticized. Instead, it is suggested that aerobic energy cost ([Formula: see text]) provides greater validity; however, a comparison of these quantification methods has not previously been made. METHODS: Fifty-six male (n = 34) and female (n = 22) competitive adolescent (17 ± 1 years) middle-distance runners participated in a sub-maximal and maximal incremental treadmill test. Running economy (RE) was measured at the speed corresponding to lactate turnpoint, and the three speeds prior. Maximal oxygen uptake ([Formula: see text]O2max), speed at [Formula: see text]O2max and fraction of [Formula: see text]O2max utilized across a range of intensities, and speeds from 0.8, 1.5 and 3 km races were also quantified. RE and fractional utilization were calculated in units of [Formula: see text]aero and [Formula: see text]aero. RESULTS: Multiple linear regression models demonstrated no discernible difference in the predictive capability of RE, fractional utilization and [Formula: see text]O2max when expressed as [Formula: see text]aero or [Formula: see text]aero in both sexes. When plotted as a function of running speed, [Formula: see text]aero displayed a stepwise decrease (F = 11.59, p < 0.001) whereas [Formula: see text]aero exhibited a curvilinear response (F = 4.74, p = 0.015). Differences were also evident in the slopes plotted for %[Formula: see text]O2max and %[Formula: see text]aeromax against running speed (F = 5.38, p = 0.021). CONCLUSIONS: Quantifying aerobic determinants of performance in units of [Formula: see text]aero provides no greater validity compared to [Formula: see text]aero-based measurement. Although both [Formula: see text]aero and [Formula: see text]aero are sensitive to changes in speed, [Formula: see text]aero provides the more valid reflection of the underlying metabolic cost of running. Physiologists should also be aware of the potential differences between expression of aerobic running intensity based upon %[Formula: see text]O2max compared to %[Formula: see text]aeroma

Effects of montmorency tart cherry (L. Prunus Cerasus) consumption on nitric oxide biomarkers and exercise performance

The purpose of this study was to investigate the effects of Montmorency tart cherry juice (MC) on nitric oxide (NO) biomarkers, vascular function and exercise performance. In a randomized, double blind, placebo (PLA) – controlled, crossover study, 10 trained cyclists (mean ± SD; V̇O2peak 59.0 ± 7.0 ml/kg/min) acutely ingested 30 mL of either MC or PLA following dietary restrictions of polyphenol‐rich compounds, and completed 6 min moderate‐ and severe‐intensity cycling bouts 1.5 h post ingestion on two occasions for each experimental condition. The severe‐intensity cycling test was continued to exhaustion on one occasion and immediately followed by a 60 s all‐out sprint on the other occasion. Blood pressure, pulse wave measures, tissue oxygenation index and plasma nitrite concentration were assessed pre and 1.5 h post ingestion. Time to exhaustion was not different between conditions (P > 0.05), but peak power over the first 20 s (363 ± 42 vs. 330 ± 26 W) and total work completed during the 60 s all‐out sprint (21 ± 3 vs. 19 ± 3 kJ) were 10% higher in the MC trial compared to the PLA trial (P 0.05). These results suggest that acute supplementation with MC can lower blood pressure and improve some aspects of exercise performance, specifically end‐sprint performance, in trained cyclists

Reliabilty of traditional and task specific reference tasks to assess peak muscle activation during two different sprint cycling tests

© 2019 Elsevier Ltd Neuromuscular activation is considered an important determinant sprint cycling performance but requires reliable EMG amplitude measurements to facilitate sensitive assessments. The reliability of EMG measurements during sprint cycling may depend on the sprint cycling test undertaken (isovelocity or isoinertial accelerating), the reference tasks used for normalisation (isometric MVCs of a series of single muscle groups [ISO-SINGJT] or isometric cycling MVCs [ISO-CYC]), and the efficacy of the normalisation. This study aimed to compare the magnitude and between-session reliability of peak muscle activation (peak rmsEMG) during: isovelocity and isoinerital sprint cycling tests; ISO-SINGJT and ISO-CYC reference tasks; and absolute and normalised EMG during the sprint cycling tests. EMG amplitude was measured over six major muscle groups on both legs and all measurements were made over two sessions in a randomised counterbalanced design. Peak rmsEMG was assessed during both ISO-SINGJT and ISO-CYC MVCs and then during mechanical peak power output (PPO) during isovelocity (120 RPM) and isoinerital acceleration (0 to >150 RPM) sprint tests. Absolute peak rmsEMG and for the sprint tests normalised EMG values were determined, and coefficient of variation and intra-class correlation coefficients used to assess reliability. Peak rmsEMG at PPO during both sprint cycling tests was similar for the six muscle groups measured. Peak rmsEMG was higher during ISO-SINGJT than ISO-CYC for for 3 of the 6 muscle groups, but all muscle groups exhibited similar reliability for both reference tasks. Neither reference task improved the between-session reliability for either sprint test. This data highlights reservations in the use of isometric reference tasks to ascertain changes in peak muscle activation over time in during sprint cycling assessments

Efficacy of depth jumps to elicit a post-activation performance enhancement in junior endurance runners

Objectives: To determine the effect of performing depth jumps (DJ) pre-exercise on running economy (RE) and time to exhaustion (TTE) at the speed associated with maximal oxygen uptake (sV˙O2max) in a group of high-performing junior middle-distance runners. Design: Randomized crossover study. Methods: Seventeen national- and international-standard male distance runners (17.6 ± 1.2 years, 63.4 ± 6.3 kg, 1.76 ± 0.06 m, 70.7 ± 5.2 mL kg−1 min−1) completed two trials. Following a 5 min warm-up at 60% V˙O2max, participants performed a 5 min run at 20%Δ below oxygen uptake corresponding with lactate turn-point to determine pre-intervention RE. Participants then completed either six DJ from a box equivalent to their best counter-movement jump (CMJ) or a control condition (C) involving body weight quarter squats. After a 10 min passive recovery, another 5 min sub-maximal run was performed followed by a run to exhaustion at sV˙O2max. Results: Compared to the C trial, DJ produced moderate improvements (−3.7%, 95% confidence interval for effect size: 0.25–1.09) in RE, which within the context of minimal detectable change is considered possibly beneficial. Differences in TTE and other physiological variables were most likely trivial (ES: <0.2). Individual responses were small, however a partial correlation revealed a moderate relationship (r = −0.55, p = 0.028) between change in RE and CMJ height. Conclusions: The inclusion of a set of six DJ in the warm-up routine of a well-trained young male middle-distance runner is likely to provide a moderate improvement in RE

The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans

Purpose: To evaluate the plasma bioavailability of betanin and nitric oxide (NOx) after consuming beetroot juice (BTJ) and whole beetroot (BF). BTJ and BF were also analysed for antioxidant capacity, polyphenol content (TPC) and betalain content. Methods: Ten healthy males consumed either 250 ml of BTJ, 300 g of BF or a placebo drink, in a randomised, crossover design. Venous plasma samples were collected pre (baseline), 1, 2, 3, 5 and 8 h post-ingestion. Betanin content in BTJ, BF and plasma was analysed with reverse-phase high-performance liquid chromatography (HPLC) and mass spectrometry detection (LCMS). Antioxidant capacity was estimated using the Trolox equivalent antioxidant capacity (TEAC) and polyphenol content using Folin–Ciocalteu colorimetric methods [gallic acid equivalents (GAE)] and betalain content spectrophotometrically. Results: TEAC was 11.4 ± 0.2 mmol/L for BTJ and 3.4 ± 0.4 μmol/g for BF. Both BTJ and BF contained a number of polyphenols (1606.9 ± 151 mg/GAE/L and 1.67 ± 0.1 mg/GAE/g, respectively), betacyanins (68.2 ± 0.4 mg/betanin equivalents/L and 19.6 ± 0.6 mg/betanin equivalents/100 g, respectively) and betaxanthins (41.7 ± 0.7 mg/indicaxanthin equivalents/L and 7.5 ± 0.2 mg/indicaxanthin equivalents/100 g, respectively). Despite high betanin contents in both BTJ (~194 mg) and BF (~66 mg), betanin could not be detected in the plasma at any time point post-ingestion. Plasma NOx was elevated above baseline for 8 h after consuming BTJ and 5 h after BF (P < 0.05). Conclusions: These data reveal that BTJ and BF are rich in phytonutrients and may provide a useful means of increasing plasma NOx bioavailability. However, betanin, the major betalain in beetroot, showed poor bioavailability in plasma

The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans

Purpose: To evaluate the plasma bioavailability of betanin and nitric oxide (NOx) after consuming beetroot juice (BTJ) and whole beetroot (BF). BTJ and BF were also analysed for antioxidant capacity, polyphenol content (TPC) and betalain content. Methods: Ten healthy males consumed either 250 ml of BTJ, 300 g of BF or a placebo drink, in a randomised, crossover design. Venous plasma samples were collected pre (baseline), 1, 2, 3, 5 and 8 h post-ingestion. Betanin content in BTJ, BF and plasma was analysed with reverse-phase high-performance liquid chromatography (HPLC) and mass spectrometry detection (LCMS). Antioxidant capacity was estimated using the Trolox equivalent antioxidant capacity (TEAC) and polyphenol content using Folin–Ciocalteu colorimetric methods [gallic acid equivalents (GAE)] and betalain content spectrophotometrically. Results: TEAC was 11.4 ± 0.2 mmol/L for BTJ and 3.4 ± 0.4 μmol/g for BF. Both BTJ and BF contained a number of polyphenols (1606.9 ± 151 mg/GAE/L and 1.67 ± 0.1 mg/GAE/g, respectively), betacyanins (68.2 ± 0.4 mg/betanin equivalents/L and 19.6 ± 0.6 mg/betanin equivalents/100 g, respectively) and betaxanthins (41.7 ± 0.7 mg/indicaxanthin equivalents/L and 7.5 ± 0.2 mg/indicaxanthin equivalents/100 g, respectively). Despite high betanin contents in both BTJ (~194 mg) and BF (~66 mg), betanin could not be detected in the plasma at any time point post-ingestion. Plasma NOx was elevated above baseline for 8 h after consuming BTJ and 5 h after BF (P < 0.05). Conclusions: These data reveal that BTJ and BF are rich in phytonutrients and may provide a useful means of increasing plasma NOx bioavailability. However, betanin, the major betalain in beetroot, showed poor bioavailability in plasma

Effects of strength training on postpubertal adolescent distance runners

Purpose Strength training activities have consistently been shown to improve running economy (RE) and neuromuscular characteristics, such as force-producing ability and maximal speed, in adult distance runners. However, the effects on adolescent (<18 yr) runners remains elusive. This randomized control trial aimed to examine the effect of strength training on several important physiological and neuromuscular qualities associated with distance running performance. Methods Participants (n = 25, 13 female, 17.2 ± 1.2 yr) were paired according to their sex and RE and randomly assigned to a 10-wk strength training group (STG) or a control group who continued their regular training. The STG performed twice weekly sessions of plyometric, sprint, and resistance training in addition to their normal running. Outcome measures included body mass, maximal oxygen uptake (VO 2max ), speed at VO 2max , RE (quantified as energy cost), speed at fixed blood lactate concentrations, 20-m sprint, and maximal voluntary contraction during an isometric quarter-squat. Results Eighteen participants (STG: n = 9, 16.1 ± 1.1 yr; control group: n = 9, 17.6 ± 1.2 yr) completed the study. The STG displayed small improvements (3.2%-3.7%; effect size (ES), 0.31-0.51) in RE that were inferred as "possibly beneficial" for an average of three submaximal speeds. Trivial or small changes were observed for body composition variables, VO 2max and speed at VO 2max ; however, the training period provided likely benefits to speed at fixed blood lactate concentrations in both groups. Strength training elicited a very likely benefit and a possible benefit to sprint time (ES, 0.32) and maximal voluntary contraction (ES, 0.86), respectively. Conclusions Ten weeks of strength training added to the program of a postpubertal distance runner was highly likely to improve maximal speed and enhances RE by a small extent, without deleterious effects on body composition or other aerobic parameters

Quantification of exercise intensity as energy expenditure: reliability and units of measurement [commentary]

This is a commentary on Beck ON, Kipp S, Byrnes WC, Kram R. Viewpoint: Use aerobic energy expenditure instead of oxygen uptake to quantify exercise intensity and predict endurance performance. </p