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This study investigated whether a heavy-intensity priming exercise precisely prescribed within the heavy-intensity domain would lead to a greater peak-power output (POpeak) and a longer maximal oxygen uptake (V̇ o 2max) plateau. Twelve recreationally active adults participated in this study. Two visits were required: 1) a step-ramp-step test [ramp-incremental (RI) control], and 2) an RI test preceded by a priming exercise within the heavy-intensity domain (RI primed). A piecewise equation was used to quantify the V̇ o 2 plateau duration (V̇ o 2plateau-time). The mean response time (MRT) was computed during the RI control condition. The delta (Δ) V̇ o 2 slope (S; mL·min−1·W−1) and V̇ o 2-Y intercept (Y; mL·min−1) within the moderate-intensity domain between conditions (RI primed minus RI control) were also assessed using a novel graphical analysis. V̇ o 2plateau-time (P = 0.001; d = 1.27) and POpeak (P = 0.003; d = 1.08) were all greater in the RI primed. MRT (P < 0.001; d = 2.45) was shorter in the RI primed compared with the RI control. A larger ΔV̇ o 2plateau-time was correlated with a larger ΔMRT between conditions (r = –0.79; P = 0.002). This study demonstrated that heavy-intensity priming exercise lengthened the V̇ o 2plateau-time and increased POpeak. The overall faster RI-V̇ o 2 responses seem to be responsible for the longer V̇ o 2plateau-time. Specifically, a shorter MRT, but not changes in RI-V̇ o 2-slopes, was associated with a longer V̇ o 2plateau-time following priming exercise. NEW & NOTEWORTHY: It remains unclear whether priming exercise extends the maximal oxygen uptake (V̇ o 2max) plateau and increases peak-power output (POpeak) during ramp-incremental (RI) tests. This study demonstrates that a priming exercise, precisely prescribed within the heavy-intensity domain, extends the plateau at V̇ o 2max and leads to a greater POpeak. Specifically, the extended V̇ o 2max plateau was associated with accelerated RI-V̇ o 2 responses. [ABSTRACT FROM AUTHOR]

MacDougall, KB, McClean, ZJ, MacIntosh, BR, Fletcher, JR, and Aboodarda, SJ. Ischemic preconditioning, but not priming exercise, improves exercise performance in trained rock climbers. J Strength Cond Res 37(11): 2149-2157, 2023--To assess the effects of ischemic preconditioning (IPC) and priming exercise on exercise tolerance and performance fatigability in a rock climbing-specific task, 12 rock climbers completed familiarization and baseline tests, and constant-load hangboarding tests (including 7 seconds on and 3 seconds off at an intensity estimated to be sustained for approximately 5 minutes) under 3 conditions: (a) standardized warm-up (CON), (b) IPC, or (c) a priming warm-up (PRIME). Neuromuscular responses were assessed using the interpolated twitch technique, including maximum isometric voluntary contraction (MVC) of the finger flexors and median nerve stimulation, at baseline and after the performance trial. Muscle oxygenation was measured continuously using near-infrared spectroscopy (NIRS) across exercise. Time to task failure (Tlim) for IPC (316.4 6 83.1 seconds) was significantly greater than CON (263.66 69.2 seconds) (p 5 0.028), whereas there was no difference between CON and PRIME (258.9 6 101.8 seconds). At task failure, there were no differences in MVC, single twitch force, or voluntary activation across conditions; however, recovery of MVC and single twitch force after the performance trial was delayed for IPC and PRIME compared with CON (p, 0.05). Despite differences in Tlim, there were no differences in any of the NIRS variables assessed. Overall, despite exercise tolerance being improved by an average of 20.0% after IPC, there were no differences in neuromuscular responses at task failure, which is in line with the notion of a critical threshold of peripheral fatigue. These results indicate that IPC may be a promising precompetition strategy for rock climbers, although further research is warranted to elucidate its mechanism of action. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether ballistic exercise priming (BEP) or heavy resistance priming (HRP) is more effective for improving ballistic performance after 24 hours. Ten resistance-trained men performed BEP and HRP conditions 72-144 hours apart in a randomized and counterbalanced order. Jumping performance was assessed before and 24 hours after the BEP and HRP sessions using 0 and 40% one-repetition maximum (1RM) squat jump (SJ), 0 and 40% 1RM countermovement jump (CMJ), and drop jump (DJ) reactive strength index (RSI). Statistical significance was accepted at p ≤ 0.05. In the BEP condition, 0% 1RM CMJ height (+3.62%) as well as theoretical maximum velocity (+5.14%) and theoretical maximum power (+2.55%) obtained from CMJ 24 hours after the priming session were significantly greater than those at the baseline (p ≤ 0.05), but 0% 1RM SJ height and DJ RSI (p > 0.05) were not greater than those at the baseline. In the HRP condition, the jump performances were not improved (p > 0.05). The percentage change in0% 1RM CMJ height in the BEP condition was significantly greater than that seen in the HRP condition (p = 0.015) but did not differ for 0% 1RM SJ height and DJ RSI (p > 0.05). These results suggest that the BEP is more effective than HRP in improving CMJ performance after 24 hours. Therefore, practitioners should consider prescribing resistance priming using low-load ballistic exercises rather than high-load traditional exercises when planning to enhance athlete performance on the following day. [ABSTRACT FROM AUTHOR]

Postactivation potentiation (PAP) mechanisms and responses have a long scientific history. However, to this day there is still controversy regarding the mechanisms underlying enhanced performance after a conditioning activity. More recently, the term postactivation performance enhancement (PAPE) has been proposed with differing associated mechanisms and protocols than with PAP. However, these 2 terms (PAP and PAPE) may not adequately describe all specific potentiation responses and mechanisms and can also be complementary, in some cases. Purpose: This commentary presents and discusses the similarities and differences between PAP and PAPE and, subsequently, elaborates on a new taxonomy for better describing performance potentiation in sport settings. Conclusion: The elaborated taxonomy proposes the formula "Post-[CONDITIONING ACTIVITY] [VERIFICATION TEST] potentiation in [POPULATION]." This taxonomy would avoid erroneous identification of isolated physiological attributes and provide individualization and better applicability of conditioning protocols in sport settings. [ABSTRACT FROM AUTHOR]

"Priming exercises" are gaining popularity as a precompetition strategy to improve subsequent performance. Although priming exercise has been shown to improve various neuromuscular performance measures within 48 hours, a number of studies have also found no change or significant decreases in performance following priming interventions. Inconsistencies in findings are likely due to the many different variables used in the research. In addition, evidence suggests that the potential performance response following a priming stimulus is likely to be influenced by individual characteristics. Therefore, the purpose of this review is to examine the available evidence and identify those variables that most strongly determine whether priming stimuli involving resistance and stretch-shortening cycle exercise tasks are likely to improve performance within 48 hours of that stimulus. In addition to making recommendations based on the evidence to date, directions for future research are also identified. [ABSTRACT FROM AUTHOR]

Context: An exercise bout completed several hours prior to an event may improve competitive performance later that same day. Purpose: To examine the influence of morning exercise on afternoon sprint-swimming performance. Methods: Thirteen competitive swimmers (7 male, mean age 19 ± 3 y; 6 female, mean age 17 ± 3 y) completed a morning session of 1200 m of varied-intensity swimming (SwimOnly), a combination of varied-intensity swimming and a resistance-exercise routine (SwimDry), or no morning exercise (NoEx). After a 6-h break, swimmers completed a 100-m time trial. Results: Time-trial performance was faster in SwimOnly (1.6% ± 0.6, mean ± 90% confidence limit, P < .01) and SwimDry (1.7% ± 0.7%, P < .01) than in NoEx. Split times for the 25- to 50-m distance were faster in both SwimOnly (1.7% ± 1.2%, P = .02) and SwimDry (1.5% ± 0.8%, P = .01) than in NoEx. The first 50-m stroke rate was higher in SwimOnly (0.70 ± 0.21 Hz, mean ± SD, P = .03) and SwimDry (0.69 ± 0.18 Hz, P = .05) than in NoEx (0.64 ± 0.16 Hz). Before the afternoon session, core (0.2°C ± 0.1°C [mean ± 90% confidence limit], P = .04), body (0.2°C ± 0.1°C, P = .02), and skin temperatures (0.3°C ± 0.3°C, P = .02) were higher in SwimDry than in NoEx. Conclusions: Completion of a morning swimming session alone or together with resistance exercise can substantially enhance sprint-swimming performance completed later the same day. [ABSTRACT FROM AUTHOR]

To verify the acute effect of drop jumps (DJ) on two repeated sprint ability tests (RSA), interspersed with a rest period simulating a basketball game break. Twelve first division basketball players (age: 24.8 ± 6.9 years; body mass: 97.0 ± 9.2 kg; height: 2.0 ± 0.1 m) performed, in a randomized crossover design, two RSA tests separated by 5 min after DJ or control conditions. The DJ condition comprised 5 DJs performed 4 min prior to the first RSA test, whereas 3 DJ were completed 30 s prior to a second RSA test. Surface electromyography was recorded from the lower body for root mean square (RMS) analyses during sprinting. Three countermovement jump (CMJ) tests were performed after warming up and immediately after the second RSA test. DJ improved RSA performance with a faster best time in the first RSA test (p = 0.035), and a shorter total time and mean time (p = 0.030) for the second RSA test. No significant differences were found in RMS between protocols. CMJ decreased in both conditions after the RSA tests (p < 0.05). This study revealed a post-DJ RSA potentiation in professional male basketball players. This simple and effective approach could be implemented at the end of the warm-up and before the end of game breaks to improve player preparedness to compete.

Silva, LM, Neiva, HP, Marques, MC, Izquierdo, M, and Marinho, DA. Short post-warm-up transition times are required for optimized explosive performance in team sports. J Strength Cond Res 36(4): 1134-1140, 2022-This study aimed to compare the effect of 3 different post-warm-up transition times (3, 10, and 17 minutes) on team sports performance. A randomized crossover research design was used. Fourteen university male basketball players completed the same 10-minute warm-up followed by a transition time of 3, 10, or 17 minutes until the performance assessment. In the control condition, no warm-up was performed. The performance was measured using the repeated sprint and jump ability test. Performance variables (time, jump height, and peak power) and physiological variables (lactate and tympanic temperature) were analyzed. Moderate effects were found between conditions for the best first 12.5-m sprint (F = 1.91, p = 0.17, = 0.13), with faster times after 3-minute transition (control: 2.51 +/- 0.12 vs. 3 minutes: 2.41 +/- 0.15, p = 0.02, effect size [ES] = 0.74). Jump heights were higher after transitions of 3 minutes (38.55 +/- 5.07 cm, p < 0.01, ES = 0.58), 10 minutes (37.69 +/- 4.92 cm, p < 0.01, ES = 0.40), and 17 minutes (37.87 +/- 5.33 cm, p < 0.01, ES = 0.42) compared with the control condition (35.84 +/- 4.18 cm). However, no significant differences were found between resting conditions. The warm-up caused a moderate increase in lactate and temperature compared with no activity (F = 11.90, p < 0.01, [ABSTRACT FROM AUTHOR]

To verify the acute effect of drop jumps (DJ) on two repeated sprint ability tests (RSA), interspersed with a rest period simulating a basketball game break. Twelve first division basketball players (age: 24.8 ± 6.9 years; body mass: 97.0 ± 9.2 kg; height: 2.0 ± 0.1 m) performed, in a randomized crossover design, two RSA tests separated by 5 min after DJ or control conditions. The DJ condition comprised 5 DJs performed 4 min prior to the first RSA test, whereas 3 DJ were completed 30 s prior to a second RSA test. Surface electromyography was recorded from the lower body for root mean square (RMS) analyses during sprinting. Three countermovement jump (CMJ) tests were performed after warming up and immediately after the second RSA test. DJ improved RSA performance with a faster best time in the first RSA test (p = 0.035), and a shorter total time and mean time (p = 0.030) for the second RSA test. No significant differences were found in RMS between protocols. CMJ decreased in both conditions after the RSA tests (p < 0.05). This study revealed a post-DJ RSA potentiation in professional male basketball players. This simple and effective approach could be implemented at the end of the warm-up and before the end of game breaks to improve player preparedness to compete. [ABSTRACT FROM AUTHOR]

This study investigated whether a heavy-intensity priming exercise precisely prescribed within the heavy-intensity domain would lead to a greater peak-power output (PO peak ) and a longer maximal oxygen uptake (V̇o 2max ) plateau. Twelve recreationally active adults participated in this study. Two visits were required: 1 ) a step-ramp-step test [ramp-incremental (RI) control], and 2 ) an RI test preceded by a priming exercise within the heavy-intensity domain (RI primed). A piecewise equation was used to quantify the V̇o 2 plateau duration (V̇o 2plateau-time ). The mean response time (MRT) was computed during the RI control condition. The delta (Δ) V̇o 2 slope (S; mL·min -1 ·W -1 ) and V̇o 2 -Y intercept (Y; mL·min -1 ) within the moderate-intensity domain between conditions (RI primed minus RI control) were also assessed using a novel graphical analysis. V̇o 2plateau-time ( P = 0.001; d = 1.27) and PO peak ( P = 0.003; d = 1.08) were all greater in the RI primed. MRT ( P < 0.001; d = 2.45) was shorter in the RI primed compared with the RI control. A larger ΔV̇o 2plateau-time was correlated with a larger ΔMRT between conditions ( r = -0.79; P = 0.002). This study demonstrated that heavy-intensity priming exercise lengthened the V̇o 2plateau-time and increased PO peak . The overall faster RI-V̇o 2 responses seem to be responsible for the longer V̇o 2plateau-time . Specifically, a shorter MRT, but not changes in RI-V̇o 2 -slopes, was associated with a longer V̇o 2plateau-time following priming exercise. NEW & NOTEWORTHY It remains unclear whether priming exercise extends the maximal oxygen uptake (V̇o 2max ) plateau and increases peak-power output (PO peak ) during ramp-incremental (RI) tests. This study demonstrates that a priming exercise, precisely prescribed within the heavy-intensity domain, extends the plateau at V̇o 2max and leads to a greater PO peak . Specifically, the extended V̇o 2max plateau was associated with accelerated RI-V̇o 2 responses.

This study examined the effects of an inspiratory muscle exercise as part of a warm-up (IMW) using a resisted breathing trainer on running performance. In a randomized crossover design, 17 trained distance runners completed two 3,200-m performance trials on separate days, preceded by 2 different warm-up procedures: IMW or sham IMW (CON). In each condition, subjects performed 30 breaths against either 50% of each athlete's peak strength (IMW) or 30 slow protracted breaths against negligible resistance (CON). Perceived race readiness and inspiratory muscle strength, flow, power, and volume were measured before and after each warm-up. Heart rate (HR), rating of perceived exertion (RPE) and dyspnea (RPD), and expired gases were collected during each trial. A 3,200-m run performance was 2.8% ± 1.5% (20.4-second) faster after IMW (effect size [ES] = 0.37, p = 0.02). After each warm-up condition, there was as small effect on peak inspiratory strength (6.6 ± 4.8%, ES = 0.22, p = 0.02), flow (5.2 ± 4.4%, ES = 0.20, p = 0.03), power (17.6 ± 16.7%, ES = 0.22, p = 0.04), and volume (6.7 ± 6.3%, ES = 0.24, p = 0.01) after IMW compared with CON. There were no differences in HR, minute volume, peak VO2, or VO2 at each 800-m interval between conditions (ES ≤ 0.13, p > 0.17). There were small differences in RPE at 800 m and 1,600 m (ES = 0.32, p = 0.17; ES = 0.21, p = 0.38, respectively), but no difference at the last 1,600 m (p = 1.0). There was a moderate positive effect on RPD (ES = 0.81, p < 0.001) and race readiness (ES = 0.76, p < 0.01) after IMW. Overall, the data suggest that IMW improves 3,200-m performance because of enhancements in inspiratory muscle function characteristics and reduction in dyspnea. [ABSTRACT FROM AUTHOR]

We hypothesized that the performance of prior heavy exercise would speed pulmonary oxygen uptake (V̇o2) kinetics (i.e., as described by the time constant, τV̇o2) and reduce the amplitude of muscle deoxygenation (deoxy[heme]) kinetics in the supine (S) but not upright (U) body position. Seventeen healthy men completed heavy-intensity constant-work rate exercise tests in S and U consisting of two bouts of 6-min cycling separated by 6-min cycling at 20 W. Pulmonary V̇o2 was measured breath by breath; total and deoxy[heme] were determined via time-resolved near-infrared spectroscopy (NIRS) at three muscle sites. Priming exercise reduced τV̇o2 in S (bout 1: 36 ± 10 vs. bout 2: 28 ± 10 s, P < 0.05) but not U (bout 1: 27 ± 8 s vs. bout 2: 25 ± 7 s, P > 0.05). Deoxy[heme] amplitude was increased after priming in S (bout 1: 25-28 μM vs. bout 2: 30-35 μM, P < 0.05) and U (bout 1: 13-18 μM vs. bout 2: 17-25 μM, P > 0.05), whereas baseline total[heme] was enhanced in S (bout 1: 110-179 μM vs. bout 2: 121-193 μM, P < 0.05) and U (bout 1: 123-186 μM vs. bout 2: 137-197 μM, P < 0.05). Priming exercise increased total[heme] in both S and U, likely indicating enhanced diffusive O2 delivery. However, the observation that after priming the amplitude of the deoxy[heme] response was increased in S suggests that the reduction in [Formula: see text] subsequent to priming was related to a combination of both enhanced intracellular O2 utilization and increased O2 delivery. NEW & NOTEWORTHY Here we show that oxygen uptake (V̇o2) kinetics are slower in the supine compared with upright body position, an effect that is associated with an increased amplitude of skeletal muscle deoxygenation in the supine position. After priming in the supine position, the amplitude of muscle deoxygenation remained markedly elevated above that observed during upright exercise. Hence, the priming effect cannot be solely attributed to enhanced O2 delivery, and enhancements to intracellular O2 utilization must also be contributory. [ABSTRACT FROM AUTHOR]

Purpose: We tested the hypothesis that the described increase in oxygen uptake ([Formula: see text])-plateau incidence following a heavy-severe prior exercise is caused by a steeper increase in [Formula: see text] and muscle fiber activation in the submaximal intensity domain.Methods: Twenty-one male participants performed a standard ramp test, a [Formula: see text] verification bout, an unprimed ramp test with an individualized ramp slope and a primed ramp test with the same ramp slope, which was preceded by an intensive exercise at 50% of the difference between gas exchange threshold and maximum workload. Muscle fiber activation was recorded from vastus lateralis, vastus medialis, and gastrocnemius medialis using a surface electromyography (EMG) device in a subgroup of 11 participants. Linear regression analyses were used to calculate the [Formula: see text]-([Formula: see text]) and EMG-(∆RMS/∆P) ramp test kinetics.Results: Twenty out of the 21 participants confirmed their [Formula: see text] in the verification bout. The [Formula: see text]-plateau incidence in these participants did not differ between the unprimed (n = 8) and primed (n = 7) ramp test (p = 0.500). The [Formula: see text] was lower in the primed compared to the unprimed ramp test (9.40 ± 0.66 vs. 10.31 ± 0.67 ml min-1 W-1, p < 0.001), whereas the ∆RMS/∆P did not differ between the ramp tests (0.62 ± 0.15 vs. 0.66 ± 0.14% W-1; p = 0.744).Conclusion: These findings do not support previous studies, which reported an increase in [Formula: see text]-plateau incidence as well as steeper increases in [Formula: see text] and muscle fiber activation in the submaximal intensity domain following a heavy-severe prior exercise. [ABSTRACT FROM AUTHOR]

We compared the time constant (τV̇O2) of the fundamental phase of pulmonary oxygen uptake (V̇o2) kinetics between young adult men with type 1 diabetes and healthy control subjects. We also assessed the impact of priming exercise on τV̇O2, critical power, and muscle deoxygenation in a subset of participants with type 1 diabetes. Seventeen men with type 1 diabetes and 17 healthy male control subjects performed moderate-intensity exercise to determine τV̇O2. A subset of seven participants with type 1 diabetes performed an additional eight visits, in which critical power, τV̇O2, and muscle deoxyhemoglobin + myoglobin ([HHb+Mb], via near-infrared spectroscopy) kinetics (described by a time constant, τ[HHb+Mb]) were determined with (PRI) and without (CON) a prior 6-min bout of heavy exercise. τV̇O2 was greater in participants with type 1 diabetes compared with control subjects (type 1 diabetes 50 ± 13 vs. control 32 ± 12 s; P < 0.001). Critical power was greater in PRI compared with CON (PRI 161 ± 25 vs. CON 149 ± 22 W; P < 0.001), whereas τV̇O2 (PRI 36 ± 15 vs. CON 50 ± 21 s; P = 0.006) and τ[HHb+Mb] (PRI 10 ± 5 vs. CON 17 ± 11 s; P = 0.037) were reduced in PRI compared with CON. Type 1 diabetes patients showed slower pulmonary V̇o2 kinetics compared with control subjects; priming exercise speeded V̇o2 and [HHb + Mb] kinetics and increased critical power in a subgroup with type 1 diabetes. These data therefore represent the first characterization of the power-duration relationship in type 1 diabetes and the first experimental evidence that τV̇O2 is an independent determinant of critical power in this population. NEW & NOTEWORTHY Patients with type 1 diabetes demonstrated slower oxygen uptake (V̇o2) kinetics compared with healthy control subjects. Furthermore, a prior bout of high-intensity exercise speeded V̇o2 kinetics and increased critical power in people with type 1 diabetes. Prior exercise speeded muscle deoxygenation kinetics, indicating that V̇o2 kinetics in type 1 diabetes are limited primarily by oxygen extraction and/or intracellular factors. These findings highlight the potential for interventions that decrease metabolic inertia for enhancing exercise tolerance in this condition. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the effect of an inspiratory muscle warm-up on the VO2 kinetics during submaximal intensity ergometer rowing. Ten competitive male rowers (age 23.1 ± 3.8 years; height 188.1 ± 6.3 cm; body mass 85.6 ± 6.6 kg) took part in this investigation. A submaximal constant intensity (90% PVO2max) rowing test to volitional exhaustion was carried out twice with the standard rowing warm-up (Test 1) and with the standard rowing warm-up with additional specific inspiratory muscle warm-up of two sets of 30 repetitions at 40% maximal inspiratory pressure (Test 2). We found a significant correlation between time constant (τ1) and the VO2 value at 400 s in Test 1 (r = 0.78; p < 0.05); however, no correlation was found between those parameters in Test 2. In addition, we found a positive association between VO2max from the incremental rowing test and τ1 from Test 1 (r = 0.71; p < 0.05), whereas VO2 did not correlate with τ1 from Test 2. Adding inspiratory muscle warm-up of 40% maximal inspiratory pressure to regular rowing warm-up had no significant effect on oxygen consumption kinetics during submaximal rowing tests.

The pulmonary oxygen uptake (VO2) kinetics during the transition to moderate-intensity exercise is slowed in individuals with type 2 diabetes (T2D), at least in part because of limitations in O2 delivery. The present study tested the hypothesis that a prior heavy-intensity warm-up or "priming" exercise (PE) bout would accelerate VO2 kinetics in T2D, because of a better matching of O2 delivery to utilization. Twelve middle-aged individuals with T2D and 12 healthy controls (ND) completed moderateintensity constant-load cycling bouts either without (Mod A) or with (Mod B) prior PE. The rates of muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, [HHb+Mb]) and oxygenation (i.e., tissue oxygenation index) were continuously measured by near-infrared spectroscopy at the vastus lateralis muscle. The local matching of O2 delivery to O2 utilization was assessed by the Δ[HHb_Mb]-to-ΔVO2 ratio. Both groups demonstrated an accelerated VO2 kinetics response during Mod B compared with Mod A (T2D, 32 ± 9 vs. 42 ± 12 s; ND, 28 ± 9 vs. 34 ± 8 s; means ± SD) and an elevated muscle oxygenation throughout Mod B, whereas the [HHb+Mb] amplitude was greater during Mod B only in individuals with T2D. The [HHb ± Mb] kinetics remained unchanged in both groups. In T2D, Mod B was associated with a decrease in the "overshoot" relative to steady state in the Δ[HHb+Mb]-to-ΔVO2 ratio (1.17 ± 0.17 vs. 1.05 ± 0.15), whereas no overshoot was observed in the control group before (1.04 ± 0.12) or after (1.01 ± 0.12) PE. Our findings support a favorable priming-induced acceleration of the VO2 kinetics response in middle-aged individuals with uncomplicated T2D attributed to an enhanced matching of microvascular O2 delivery to utilization. NEW & NOTEWORTHY Heavy-intensity "priming" exercise (PE) elicited faster pulmonary oxygen uptake (VO2) kinetics during moderate-intensity cycling exercise in middle-aged individuals with type 2 diabetes (T2D). This was accompanied by greater near-infrared spectroscopy- derived muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, [HHb+Mb]) responses and a reduced Δ[HHb+Mb]-to-ΔVO2 ratio. This suggests that the PE-induced acceleration in oxidative metabolism in T2D is a result of greater O2 extraction and better matching between O2 delivery and utilization. [ABSTRACT FROM AUTHOR]

New Findings What is the central question of this study? Critical power (CP) represents the highest work rate for which a metabolic steady state is attainable. The physiological determinants of CP are unclear, but research suggests that CP might be related to the time constant of phase II oxygen uptake kinetics ( [ABSTRACT FROM AUTHOR]

We examined the effect of heavy-intensity ‘priming’ exercise on the rate of adjustment of pulmonary O 2 uptake (τ V ˙ O 2p ) initiated from elevated intensities. Fourteen men (separated into two groups: τ V ˙ O 2p ≤ 25s [Fast] or τ V ˙ O 2p > 25s [Slow]) completed step-transitions from 20 W to 45% lactate threshold (LT; lower-step, LS) and 45% to 90%LT (upper-step, US) performed (i) without; and (ii) with US preceded by heavy-intensity exercise (HUS). Breath-by-breath V ˙ O 2p and near-infrared spectroscopy-derived muscle deoxygenation ([HHb + Mb]) were measured. Compared to LS, τ V ˙ O 2p was greater (p < 0.05) in US in both Fast (LS, 19 ± 4s; US, 30 ± 4s) and Slow (LS, 25 ± 5s; US, 40 ± 11s) with τ V ˙ O 2p in US being lower (p < 0.05) in Fast. In HUS, τ V ˙ O 2p in Slow was reduced (28 ± 8s, p < 0.05) and was not different (p > 0.05) from LS or Fast group US. In Slow, τ[HHb + Mb] increased (p < 0.05) in US relative to HUS; this finding coupled with a reduced τ V ˙ O 2p indicates a priming-induced improvement in matching of muscle O 2 delivery-to-O 2 utilization during transitions from elevated intensities in those with Slow but not Fast V ˙ O 2p kinetics. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the effects of two different kinds of prior exercise protocols [continuous exercise (CE) versus intermittent repeated sprint (IRS)] on oxygen uptake ( VO) kinetics parameters during high-intensity running. Methods: Thirteen male amateur futsal players (age 22.8 ± 6.1 years; mass 76.0 ± 10.2 kg; height 178.7 ± 6.6 cm; VO 58.1 ± 4.5 mL kg min) performed a maximal incremental running test for the determination of the gas exchange threshold (GET) and maximal VO ( VO). On two different days, the subjects completed a 6-min bout of high-intensity running (50 % ∆) on a treadmill that was 6-min after (1) an identical bout of high-intensity exercise (from control to CE), and (2) a protocol of IRS (6 × 40 m). Result: We found significant differences between CE and IRS for the blood lactate concentration ([La]; 6.1 versus 10.7 mmol L, respectively), VO baseline (0.74 versus 0.93 L min, respectively) and the heart rate (HR; 102 versus 124 bpm, respectively) before the onset of high-intensity exercise. However, both prior CE and prior IRS significantly increased the absolute primary VO amplitude (3.77 and 3.79 L min, respectively, versus control 3.54 L min), reduced the amplitude of the VO slow component (0.26 and 0.21 L min, respectively, versus control 0.50 L min), and decreased the mean response time (MRT; 28.9 and 28.0 s, respectively, versus control 36.9 s) during subsequent bouts. Conclusion: This study showed that different protocols and intensities of prior exercise trigger similar effects on VO kinetics during high-intensity running. [ABSTRACT FROM AUTHOR]

To investigate the effects of warm-up intensity on all-out sprint cycling performance, muscle oxygenation and metabolism, 8 trained male cyclists/triathletes undertook a 30-s sprint cycling test preceded by moderate, heavy or severe warm up and 10-min recovery. Muscle oxygenation was measured by near-infrared spectroscopy, with deoxyhaemoglobin ([HHb]) during the sprint analysed with monoexponential models with time delay. Aerobic, anaerobic-glycolytic and phosphocreatine energy provision to the sprint were estimated from oxygen uptake and lactate production. Immediately prior to the sprint, blood [lactate] was different for each warm up and higher than resting for the heavy and severe warm ups (mod. 0.94 ± 0.36, heavy 1.92 ± 0.64, severe 4.37 ± 0.93 mmol l P < 0.05), although muscle oxygenation was equally raised above rest. Mean power during the sprint was lower following severe compared to moderate warm up (mod. 672 ± 54, heavy 666 ± 56, severe 655 ± 59 W, P < 0.05). The [HHb] kinetics during the sprint were not different among conditions, although the time delay before [HHb] increased was shorter for severe versus moderate warm up (mod. 5.8 ± 0.6, heavy 5.6 ± 0.9, severe 5.2 ± 0.7 s, P < 0.05). The severe warm up was without effect on estimated aerobic metabolism, but increased estimated phosphocreatine hydrolysis, the latter unable to compensate for the reduction in estimated anaerobic-glycolytic metabolism. It appears that despite all warm ups equally increasing muscle oxygenation, and indicators of marginally faster oxygen utilisation at the start of exercise following a severe-intensity warm up, other energy sources may not be able to fully compensate for a reduced glycolytic rate in sprint exercise with potential detrimental effects on performance. [ABSTRACT FROM AUTHOR]

Warm-up is generally considered beneficial for performance, although the reduction in anaerobic glycolytic metabolism may be detrimental to sprinting. This study examined the effect of warm-up intensity on metabolism and performance in sprint cycling. The mean power was determined during a 1-min sprint on 11 trained males preceded by easy (WE), moderate (WM) or hard (WH) warm-up and a 10-min recovery. Aerobic, anaerobic glycolytic and phosphocreatine energy provision to the sprint was determined from oxygen uptake and lactate production. Blood lactate concentration before the sprint increased with the warm-up intensity (WE: 1.2±0.3; WM: 2.0±0.3; WH: 4.2±0.9 mmol/L, P<0.001), with WH reducing the increase in lactate production during exercise vs WE (WE: 11.6±1.6; WM: 10.9±1.9; WH: 9.2±1.4 mmol/L, P<0.05). Despite the lower relative anaerobic glycolytic energy provision in WH vs WE (WH: 38±5; WM: 36±6; WE: 34±3%, P<0.05), the mean power was unaffected (WE: 516±28; WM: 521±26; WH: 526±34 W, P>0.05) due to increased oxygen uptake in WH during the sprint (WE: 3.2±0.4; WM: 3.3±0.3; WH: 3.4±0.4 liters, P<0.05). This study supports a warm-up-induced reduction in glycolytic rate, although sprint performance, at least of a long duration, may be maintained due to increased oxygen utilization. [ABSTRACT FROM AUTHOR]

Abstract: Metabolic transitions from rest to high-intensity exercise were divided into two discrete steps (i.e., rest-to-moderate-intensity (R→M) and moderate-to-high-intensity (M→H)) to explore the effect of prior high-intensity ‘priming’ exercise on intramuscular [PCr] and pulmonary kinetics for different sections of the motor unit pool. It was hypothesized that [PCr] and kinetics would be unaffected by priming during R→M exercise, but that the time constants (τ) describing the fundamental [PCr] response and the phase II response would be significantly reduced by priming for M→H exercise. On three separate occasions, six male subjects completed two identical R→M/M→H ‘work-to-work’ prone knee-extension exercise bouts separated by 5min rest. Two trials were performed with measurement of pulmonary and the integrated electromyogram (iEMG) of the right m. vastus lateralis. The third trial was performed within the bore of a 1.5-T superconducting magnet for 31P-MRS assessment of muscle metabolic responses. Priming did not significantly affect the [PCr] or τ during R→M ([PCr] τ Unprimed: 24±16 vs. Primed: 22±14s; τ Unprimed: 26±8 vs. Primed: 25±9s) or M→H transitions ([PCr] τ Unprimed: 30±5 vs. Primed: 32±7s; τ Unprimed: 37±5 vs. Primed: 38±9s). However, it did reduce the amplitudes of the [PCr] and slow components by 50% and 46%, respectively, during M→H (P <0.05 for both comparisons). These effects were accompanied by iEMG changes suggesting reduced muscle fiber activation during M→H exercise after priming. It is concluded that the τ for the initial exponential change of muscle [PCr] and pulmonary following the transition from moderate-to-high-intensity prone knee-extension exercise is not altered by priming exercise. [Copyright &y& Elsevier]

We manipulated the baseline metabolic rate and body position to explore the effect of the interaction between recruitment of discrete sections of the muscle fiber pool and muscle O2 delivery on pulmonary O2 uptake (VO2) kinetics during cycle exercise. We hypothesized that phase II VO2 kinetics (τp) in the transition from moderateto severe-intensity exercise would be significantly slower in the supine than upright position because of a compromise to muscle perfusion and that a priming bout of severe-intensity exercise would return τp during supine exercise to τp during upright exercise. Eight male subjects [35 ± 13 (SD) yr] completed a series of "step" transitions to severe-intensity cycle exercise from an "unloaded" (20-W) baseline and a baseline of moderate-intensity exercise in the supine and upright body positions. τp was not significantly different between supine and upright exercise during transitions from a 20-W baseline to moderateor severe-intensity exercise but was significantly greater during moderateto severe-intensity exercise in the supine position (54 ± 19 vs. 38 ± 10 s, P < 0.05). Priming significantly reduced τp during moderateto severe-intensity supine exercise (34 ± 9 s), returning it to a value that was not significantly different from τp in the upright position. This effect occurred in the absence of changes in estimated muscle fractional O2 extraction (from the near-infrared spectroscopyderived deoxygenated Hb concentration signal), such that the priminginduced facilitation of muscle blood flow matched increased O2 utilization in the recruited fibers, resulting in a speeding of VO2 kinetics. These findings suggest that, during supine cycling, priming speeds VO2 kinetics by providing an increased driving pressure for O2 diffusion in the higher-order (i.e., type II) fibers, which would be recruited in the transition from moderate-to-severe-intensity exercise and are known to be especially sensitive to limitations in O2 supply. [ABSTRACT FROM AUTHOR]

It has been suggested that a prior bout of high-intensity exercise has the potential to enhance performance during subsequent high-intensity exercise by accelerating the O2 uptake (...O2) on-response. However, the optimal combination of prior exercise intensity and subsequent recovery duration required to elicit this effect is presently unclear. Eight male participants, aged 18-24 yr, completed step cycle ergometer exercise tests to 80% of the difference between the preestablished gas exchange threshold and maximal ...O2 (i.e., 80%Δ) after no prior exercise (control) and after six different combinations of prior exercise intensity and recovery duration: 40%Δ with 3 min (40-3-80), 9 min (40-9-80), and 20 min (40-20-80) of recovery and 70%Δ with 3 min (70-3-80), 9 min (70-9-80), and 20 min (70-20-80) of recovery. Overall O2 kinetics were accelerated relative to control in all conditions except for 40-9-80 and 40-20-80 conditions as a consequence of a reduction in the ...O2 slow component amplitude; the phase II time constant was not significantly altered with any prior exercise/recovery combination. Exercise tolerance at 80%Δ was improved by 15% and 30% above control in the 70-9-80 and 70-20-80 conditions, respectively, but was impaired by 16% in the 70-3-80 condition. Prior exercise at 40%Δ did not significantly influence exercise tolerance regardless of the recovery duration. These data demonstrate that prior high-intensity exercise (∼70%Δ) can enhance the tolerance to subsequent high-intensity exercise provided that it is coupled with adequate recovery duration (≥9 min). This combination presumably optimizes the balance between preserving the effects of prior exercise on ...O2 kinetics and providing sufficient time for muscle homeostasis (e.g., muscle phosphocreatine and H+ concentrations) to be restored. [ABSTRACT FROM AUTHOR]

Prior heavy exercise markedly alters the O2 uptake (V̇o2) response to subsequent heavy exercise. However, the time required for V̇o2 to return to its normal profile following prior heavy exercise is not known. Therefore, we examined the V̇o2 responses to repeated bouts of heavy exercise separated by five different recovery durations. On separate occasions, nine male subjects completed two 6-min bouts of heavy cycle exercise separated by 10, 20, 30, 45, or 60 min of passive recovery. The second-by-second V̇o2 responses were modeled using nonlinear regression. Prior heavy exercise had no effect on the primary V̇o2 time constant (from 25.9 ± 4.7 s to 23.9 ± 8.8 s after 10 min of recovery; P = 0.338), but it increased the primary V̇o2 amplitude (from 2.42 ± 0.39 to 2.53 ± 0.41 l/min after 10 min of recovery; P = 0.001) and reduced the V̇o2 slow component (from 0.44 ± 0.13 to 0.21 ± 0.12 I/min after 10 min of recovery; P < 0.001). The increased primary amplitude was also evident after 20–45 mm, but not after 60 min, of recovery. The increase in the primary V̇02 amplitude was accompanied by an increased baseline blood lactate concentration (to 5.1 ± 1.0 mM after 10 min of recovery; P < 0.001). Baseline blood lactate concentration was still elevated after 20–60 min of recovery. The priming effect of prior heavy exercise on the V̇o2 response persists for at least 45 min, although the mechanism underpinning the effect remains obscure. [ABSTRACT FROM AUTHOR]

The effects of prior heavy-intensity exercise on O2 uptake (Vo2) kinetics of a second heavy exercise may be due to vasodilation (associated with metabolic acidosis) and improved muscle blood flow. This study examined the effect of prior heavy-intensity exercise on femoral artery blood flow (Qleg) and its relationship with Vo2 kinetics. Five young subjects completed five to eight repeats of two 6-min bouts of heavy-intensity one-legged, knee-extension exercise separated by 6 min of loadless exercise. Vo2 was measured breath by breath. Pulsed-wave Doppler ultrasound was used to measure Qleg. Vo2 and blood flow velocity data were fit using a monoexponential model to identify phase II and phase III time periods and estimate the response amplitudes and time constants (τ). Phase II Vo2 kinetics was speeded on the second heavy-intensity exercise [mean τ (SD), 29 (10) s to 24 (10) s, P « 0.05] with no change in the phase II (or phase III) amplitude. Qleg was elevated before the second exercise [1.55 (0.34) l/min to 1.90 (0.25) l/min, P « 0.05], but the amplitude and time course [τ, 25 (13) s to 35 (13) s] were not changed, such that throughout the transient the Qleg (and ΔQleg/ΔVo2) did not differ from the prior heavy exercise. Thus Vo2 kinetics were accelerated on the second exercise, but the faster kinetics were not associated with changes in Qleg. Thus limb blood flow appears not to limit Vo2 kinetics during single-leg heavy-intensity exercise nor to be the mechanism of the altered Vo2 response after heavy-intensity prior exercise. [ABSTRACT FROM AUTHOR]

We hypothesized that the metabolic acidosis resulting from the performance of multiple-sprint exercise would enhance muscle perfusion and result in a speeding of pulmonary oxygen uptake (VO2) kinetics during subsequent perimaximal-intensity constant work rate exercise, if O2 availability represented a limitation to VO2 kinetics in the control (i.e., no prior exercise) condition. On two occasions, seven healthy subjects completed two bouts of exhaustive cycle exercise at a work rate corresponding to ∼105% of the predetermined VO2 peak, separated by 3 × 30-s maximal sprint cycling and 15-min recovery (MAX1 and MAX2). Blood lactate concentration (means ± SD: MAX1: 1.3 ± 0.4 mM vs. MAX2:7.7 ± 0.9 mM; P < 0.01) was significantly greater immediately before, and heart rate was significantly greater both before and during, perimaximal exercise when it was preceded by multiple-sprint exercise. Near-infrared spectroscopy also indicated that muscle blood volume and oxygenation were enhanced when perimaximal exercise was preceded by multiple-sprint exercise. However, the time constant describing the primary component (i.e., phase II) increase in VO2 was not significantly different between the two conditions (MAX1: 33.8 ± 5.5 s vs. MAX2:33.2 ± 7.7 s). Rather, the asymptotic "gain" of the primary VO2 response was significantly increased by the performance of prior sprint exercise (MAX1: 8.1 ± 0.9 ml·min-1·W-1 vs. MAX2:9.0 ± 0.7 l·min-1·W-1; P < 0.05), such that VO2 was projecting to a higher "steady-state" amplitude with the same time constant. These data suggest that priming exercise, which apparently increases muscle O2 availability, does not influence the time constant of the primary-component VO2 response but does increase the amplitude to which VO2 may rise following the onset of perimaximal-intensity cycle exercise. [ABSTRACT FROM AUTHOR]

To verify the acute effect of drop jumps (DJ) on two repeated sprint ability tests (RSA), interspersed with a rest period simulating a basketball game break. Twelve first division basketball players (age: 24.8 ± 6.9 years; body mass: 97.0 ± 9.2 kg; height: 2.0 ± 0.1 m) performed, in a randomized crossover design, two RSA tests separated by 5 min after DJ or control conditions. The DJ condition comprised 5 DJs performed 4 min prior to the first RSA test, whereas 3 DJ were completed 30 s prior to a second RSA test. Surface electromyography was recorded from the lower body for root mean square (RMS) analyses during sprinting. Three countermovement jump (CMJ) tests were performed after warming up and immediately after the second RSA test. DJ improved RSA performance with a faster best time in the first RSA test (p = 0.035), and a shorter total time and mean time (p = 0.030) for the second RSA test. No significant differences were found in RMS between protocols. CMJdecreased in both conditions after the RSA tests (p < 0.05). This study revealed a post-DJ RSA potentiation in professional male basketball players. This simple and effective approach could be implemented at the end of the warm-up and before the end of game breaks to improve player preparedness to compete., Competing Interests: None of the authors have conflicts of interest to declare, (Copyright © Biology of Sport 2021.)

The aim of the study was to investigate the effect of an inspiratory muscle warm-up on the VO2 kinetics during submaximal intensity ergometer rowing. Ten competitive male rowers (age 23.1 ± 3.8 years; height 188.1 ± 6.3 cm; body mass 85.6 ± 6.6 kg) took part in this investigation. A submaximal constant intensity (90% PVO2max) rowing test to volitional exhaustion was carried out twice with the standard rowing warm-up (Test 1) and with the standard rowing warm-up with additional specific inspiratory muscle warm-up of two sets of 30 repetitions at 40% maximal inspiratory pressure (Test 2). We found a significant correlation between time constant (τ1) and the VO2 value at 400 s in Test 1 (r = 0.78; p < 0.05); however, no correlation was found between those parameters in Test 2. In addition, we found a positive association between VO2max from the incremental rowing test and τ1 from Test 1 (r = 0.71; p < 0.05), whereas VO2 did not correlate with τ1 from Test 2. Adding inspiratory muscle warm-up of 40% maximal inspiratory pressure to regular rowing warm-up had no significant effect on oxygen consumption kinetics during submaximal rowing tests. [ABSTRACT FROM AUTHOR]