Effect of conditioning contraction intensity on postactivation potentiation is muscle dependent

Post-activation potentiation after isometric contractions is strongly related to contraction intensity despite the similar torque-time integral

Post-activation potentiation (PAP) is defined as an enhanced contractile response of a muscle following its own contractile activity and is influenced by the intensity and duration of the conditioning contraction. The aim of this study was to determine if the combination of intensity and duration, that is, torque-time integral (TTI) is a determinant of PAP amplitude. We compared PAP amplitude following low-to-maximal voluntary conditioning contraction intensities with and without similar TTI in the knee extensors. Twelve healthy males completed two experimental sessions. Femoral nerve stimulation was applied to evoke single twitches on the relaxed quadriceps before and after isometric conditioning contractions of knee extensors. In one session, participants performed conditioning contractions without similar TTI (6 s at 100, 80, 60, 40 and 20% maximal voluntary contraction (MVC)), while they performed conditioning contractions with similar TTI in the other session (6 s at 100%, 7.5 s at 80%, 10 s at 60%, 15 s at 40%, and 30 s at 20% MVC). In both sessions, PAP amplitude was related to conditioning contraction intensity. The higher the conditioning contraction intensity with or without similar TTI, the higher PAP. Significant correlations were found (i) between PAP and conditioning contraction intensity with (r2 = 0.70; P < 0.001) or without similar TTI (r2 = 0.64; P < 0.001), and (ii) between PAP with and without similar TTI (r2 = 0.82; P < 0.001). The results provide evidence that TTI has a minor influence on PAP in the knee extensors. This suggests that to optimize the effect of PAP, it is more relevant to control the intensity of the contraction rather than the TTI.

Acute Effects of Isometric Conditioning Activity on the Viscoelastic Properties of Muscles and Sprint and Jumping Performance in Handball Players

ABSTRACT

Krzysztofik, M, Spieszny, M, Trybulski, R, Wilk, M, Pisz, A, Kolinger, D, Filip-Stachnik, A, and Stastny, P. Acute effects of isometric conditioning activity on the viscoelastic properties of muscles and sprint and jumping performance in handball players. J Strength Cond Res 37(7): 1486-1494, 2023-The effects of conditioning activity (CA) on muscle stiffness are currently unknown, suggesting that maximum CA effort can increase or decrease the stiffness of involved muscle groups. Therefore, this study aimed to investigate the effect of maximal isometric half-squats on the viscoelastic properties of muscles and postactivation performance enhancement (PAPE) in sprints and jumps. Twelve handball players underwent a standard warm-up and baseline assessment of muscle stiffness and tone of vastus lateralis and gastrocnemius medialis muscle, followed by 20-m sprint with intermediate measures at 5 and 10 m and countermovement jump. The PAPE was assessed by repeating the tests (at 4th, 8th, and 12th minute post-CA) after a CA protocol consisting of 3 sets of 3-second maximal isometric half-squats (EXP) or a control condition (CTRL) without any CA. The vastus lateralis stiffness in the 4th and 12th minute and muscle tone in the 4th minute post-CA significantly decreased compared with baseline ( p = 0.041, ES = 0.57; p = 0.013, ES = 0.52; p = 0.004, ES = 0.81, respectively) in the EXP condition. The 20-m sprint time significantly decreased at all post-CA time points compared with the baseline for the EXP condition ( p < 0.033) and the after values in the CTRL condition ( p < 0.036). In comparison to baseline, the 10-m sprint time decreased in the eighth minute post-CA ( p = 0.021; ES = 0.82) in the EXP condition. Moreover, it was significantly lower at the 8th and 12th minute post-CA ( p = 0.038; ES = 0.71 and p = 0.005; ES = 1.26) compared with that time points in the CTRL condition. The maximal isometric half-squats effectively improved sprint performance and significantly decreased vastus lateralis tone and stiffness. These findings offer new insights into the assessment of viscoelastic properties for evaluating the fatigue or potentiation state, which requires further investigation.

Post-activation potentiation induced by concentric contractions at three speeds in humans

NEW FINDINGS

What is the central question of this study? Is the degree of in human muscle affected by different shortening velocities, or contraction type? What are the main findings and their importance? The PAP response following maximal concentric contractions was independent of velocity. Slow and moderate velocity maximal contractions produced PAP responses like those from maximal isometric contractions when matched for contraction duration. Despite contraction type differences in cross-bridge and Ca²⁺ kinetics, maximal contractions, regardless of contraction modality, likely generate sufficient Ca²⁺ to induce maximal PAP.

ABSTRACT

Post-activation potentiation (PAP) is the acute enhancement of contractile properties following a brief (<10 s) high-intensity contraction. Compared with isometric contractions, little is known about the PAP response induced by concentric conditioning contractions (CCs) and the effect of velocity. In the dorsiflexors of 11 participants, twitch responses were measured following 5 s of maximal effort concentric CCs at each of 10, 20 and 50°/s. Concentric PAP responses were compared to a maximal isometric voluntary contraction (MVC) matched for contraction time. Additionally, concentric CCs were compared to isometric CCs matched for mean torque, contraction area and time. The PAP response following maximal concentric CCs was independent of velocity and there was no difference in the PAP response between concentric CCs and an isometric MVC. During maximal contractions, regardless of contraction modality, there is likely sufficient Ca²⁺ to induce a similar full PAP response, and thus there was no difference between speeds or contraction type. Following concentric CCs there was a significantly larger peak twitch torque than following their isometric torque matches (49-58%), and faster maximal rates of torque development at the three speeds (62-77%). However, these responses are likely related to greater EMG in concentric contractions, 125-129% of isometric maximum compared to 38-54%, and not to contraction modality per se. Thus, PAP responses following maximal concentric CCs are not affected by velocity and responses are not different from an isometric MVC. This indicates maximal CCs of 5 s produce a maximal PAP response independent of contraction type (isometric vs. concentric) or shortening velocity.

Plyometric exercise enhances twitch contractile properties but fails to improve voluntary rate of torque development in highly trained sprint athletes

Purpose: The objective of this study was to evaluate a plyometric conditioning activity (3 sets of 5 countermovement jumps, [CA]) for twitch properties and voluntary knee extension. Methods: After a familiarization session, fourteen highly trained sprint athletes, 12 men (23.25 ± 7.17 years) and 2 women (23.0 ± 2.8 years) performed 2 experiments, each in a randomized order (crossover design). In one experiment, the time-course of twitch contractile properties was evaluated with and without the previous CA at 2, min intervals to 10 min of recovery. In the second session, maximal voluntary knee extension was evaluated at the same recovery intervals, for control and experimental condition in random order. Results: Mixed-model ANOVA with Bonferroni post-hoc revealed significant differences between pre-test and 2 min (p < 0.01, ES = 0.42) and 4 min (p < 0.01, ES = 0.20) for peak twitch torque of quadriceps femoris muscles confirming postactivation potentiation [PAP] at these times. Twitch rate of torque development (RTD) was significantly greater than pre-test value only at 2 min (p < 0.01, ES = 0.58) after the CA. Twitch contraction time and ½ relaxation time were not significantly difference from pre-test values after the CA (p > 0.05). No significant difference was observed for voluntary RTD following CA. Conclusion: The plyometric CA increased twitch peak torque and RTD consistent with PAP; however, there was no effect of CA on voluntary RTD of knee extension at any time after the plyometric CA. Even with PAP confirmed, we observed that the CA fails to improve isometric RTD of quadriceps femoris muscles. HighlightsA plyometric CA significantly increased twitch peak torque (at 2 and 4 min) and twitch rate of torque development (at 2 min) of quadriceps femoris muscles, indicating postactivation potentiation (PAP).No effect was observed for twitch contraction time and ½ relaxation time after the CA.No improvement was observed on voluntary rate of torque development evaluated at the same time intervals.

Effects of Pre-Activation with Variable Intra-Repetition Resistance on Throwing Velocity in Female Handball Players: a Methodological Proposal

The purpose of this study was to investigate the acute effect of pre-activation with Variable Intra-Repetition Resistance and isometry on the overhead throwing velocity in handball players. Fourteen female handball players took part in the study (age: 21.2 ± 2.7 years, experience: 10.9 ± 3.5 years). For Post-Activation Potentiation, two pre-activation methods were used: (I) Variable Intra-Repetition Resistance: 1 x 5 maximum repetitions at an initial velocity of 0.6 m·s^-1 and a final velocity of 0.9 m·s^-1; (II) Isometry: 1 x 5 s of maximum voluntary isometric contraction. Both methods were "standing unilateral bench presses" with the dominant arm, using a functional electromechanical dynamometer. The variable analysed was the mean of the three overhead throws. Ball velocity was measured with a radar (Stalker ATS). The statistical analysis was performed using ANOVA with repeated measures. No significant differences were found for either method (variable resistance intra-repetition: p = 0.194, isometry: p = 0.596). Regarding the individual responses, the analysis showed that 86% of the sample increased throwing velocity with the variable resistance intra-repetition method, while 93% of the sample increased throwing velocity with the isometric method. Both the variable intra-repetition resistance and isometric methods show improvements in ball velocity in female handball players. However, the authors recommend checking individual responses, since the results obtained were influenced by the short rest interval between the pre-activation and the experimental sets.

The effect of neuromuscular electrical stimulation on muscle EMG activity and the initial phase rate of force development during tetanic contractions in the knee extensor muscles of healthy adult males

OBJECTIVE

Neuromuscular electrical stimulation (NMES) has been noted as an effective pre- contraction for an increase of neural and muscle factors during twitch contractions. However, it is unknown if this intervention is effective for the rate of force development (RFD), which is the ability to increase joint torque strength as quickly as possible, during tetanic contractions. NMES can be safely used by anyone, but, the strength setting of NMES requires attention so as not to cause pain. Therefore, the purpose of this study investigated whether NMES at less painful levels was effective for RFD during tetanic contractions. We also investigated effect activation by analyzing electromyogram (EMG) and RFD for each phase.

METHODS

Eighteen healthy males were studied. Before and after NMES intervention at 10% or 20% maximal voluntary isometric contraction (MVIC) level (10%NMES, 20%NMES respectively), EMG activity and the initial phase (30-, 50-, 100-, and 200-msec) RFD were measured. Visual analog scale (VAS) was also measured as an indicator of pain during each NMES.

RESULTS

20%NMES increased EMG activity and 30-, 50-, and 100-msec of RFD during MVIC, but could not improve 200 msec of RFD. However, 10%NMES could be failed to increase all phases RFD, but VAS was lower than that of 20% NMES.

CONCLUSION

These results suggest that muscle pre-contraction using 20%NMES could induce moderate pain, but could be an effective intervention to improve RFD via neural factor activity.

Coexistence of peripheral potentiation and corticospinal inhibition following a conditioning contraction in human first dorsal interosseous muscle

In skeletal muscle, postactivation potentiation (PAP) is observed following a conditioning contraction (CC) as a large (two- to three-fold) increase in evoked twitch force and rate of force development (RFD). However, this enhancement has not been observed to occur during potentiated voluntary contractions. The purpose of this study was to determine whether the lack of voluntary potentiation may be related to the development of central (corticospinal) inhibition. Participants (n = 10, all males) completed voluntary and evoked index finger abduction contractions and transcranial magnetic stimulated motor-evoked potentials (MEP) of the motor cortex were recorded from the first dorsal interosseous (FDI). Central inhibition was assessed by measuring the silent period following the MEP. The FDI was potentiated via 10-s conditioning contractions at 60% of maximal index finger abduction strength, using both voluntary and evoked tetanic contractions. Immediately following CC and transcutaneous electrical twitches. Following both voluntary and tetanic CC, force and RFD of the twitch were similarly increased (~200% and ~160%, respectively). The silent period was elongated by ~10% following both forms of CC. These results indicate that corticospinal inhibition does occur following CC, but that it is unrelated to the voluntary activation during the CC. These results also show that following CC, the positive contractile effects at the muscle are concurrently accompanied by inhibitory effects at the corticospinal level.NEW & NOTEWORTHY We demonstrate that postactivation potentiation in human skeletal muscle is accompanied by central inhibition at the corticospinal level. However, the magnitude of central inhibition does not differ between peripherally evoked or voluntary conditioning contractions. Therefore, it is possible this central inhibition is related to muscle sensory feedback.

Does postactivation potentiation (PAP) increase voluntary performance?

The transient increase in torque of an electrically evoked twitch following a voluntary contraction is called postactivation potentiation (PAP). Phosphorylation of myosin regulatory light chains is the most accepted mechanism explaining the enhanced electrically evoked twitch torque. While many authors attribute voluntary postactivation performance enhancement (PAPE) to the positive effects of PAP, few actually confirmed that contraction was indeed potentiated using electrical stimulation (twitch response) at the time that PAPE was measured. Thus, this review aims to investigate if increases in voluntary performance after a conditioning contraction (CC) are related to the PAP phenomenon. For this, studies that confirmed the presence of PAP through an evoked response after a voluntary CC and concurrently evaluated PAPE were reviewed. Some studies reported increases in PAPE when PAP reaches extremely high values. However, PAPE has also been reported when PAP was not present, and unchanged/diminished performance has been identified when PAP was present. This range of observations demonstrates that mechanisms of PAPE are different from mechanisms of PAP. These mechanisms of PAPE still need to be understood and those studying PAPE should not assume that regulatory light chain phosphorylation is the mechanism for such enhanced voluntary performance. Novelty The occurrence of PAP does not necessarily mean that the voluntary performance will be improved. Improvement in voluntary performance is sometimes observed when the PAP level reaches extremely high values. Other mechanisms may be more relevant than that for PAP in the manifestation of acute increases in performance following a conditioning contraction.

Muscle spindle thixotropy affects force perception through afferent-induced facilitation of the motor pathways as revealed by the Kohnstamm effect

This study was designed to explore the effects of intrafusal thixotropy, a property affecting muscle spindle sensitivity, on the sense of force. For this purpose, psychophysical measurements of force perception were performed using an isometric force matching paradigm of elbow flexors consisting of matching different force magnitudes (5, 10 and 20% of subjects' maximal voluntary force). We investigated participants' capacity to match these forces after their indicator arm had undergone voluntary isometric conditioning contractions known to alter spindle thixotropy, i.e., contractions performed at long ('hold long') or short muscle lengths ('hold short'). In parallel, their reference arm was conditioned at the intermediate muscle length ('hold-test') at which the matchings were performed. The thixotropy hypothesis predicts that estimation errors should only be observed at low force levels (up to 10% of the maximal voluntary force) with overestimation of the forces produced following 'hold short' conditioning and underestimation following 'hold long' conditioning. We found the complete opposite, especially following 'hold-short' conditioning where subjects underestimated the force they generated with similar relative error magnitudes across force levels. In a second experiment, we tested the hypothesis that estimation errors depended on the degree of afferent-induced facilitation using the Kohnstamm phenomenon as a probe of motor pathway excitability. Because the stronger post-effects were observed following 'hold-short' conditioning, it appears that the conditioning-induced excitation of spindle afferents leads to force misjudgments by introducing a decoupling between the central effort and the cortical motor outputs.

Post Activation Potentiation of the Plantarflexors: Implications of Knee Angle Variations

Flexing the knee to isolate the single joint soleus from the biarticular gastrocnemius is a strategy for investigating individual plantarflexor’s post activation potentiation (PAP). We investigated the implications of testing plantarflexor PAP at different knee angles and provided indirect quantification of the contribution of gastrocnemius potentiation to the overall plantarflexor enhancements post conditioning. Plantarflexor supramaximal twitches were measured in ten male power athletes before and after a maximal isometric plantarflexion (MVIC) at both flexed and extended knee angles. Mean torque and soleus (SOL_RMS) and medial gastrocnemius (MG_RMS) activity were measured during the MVIC. The mean torque and MG_RMS of the MVIC were lower (by 33.9 and 42.4%, respectively) in the flexed compared to the extended position, with no significant difference in SOL_RMS. After the MVIC, twitch peak torque (PT) and the rate of torque development (RTR) potentiated significantly more (by 17.4 and 14.7% respectively) in the extended as compared to the flexed knee position, but only immediately (5 s) after the MVIC. No significant differences were found in the twitch rate of torque development (RTD) potentiation between positions. It was concluded that knee joint configuration should be taken into consideration when comparing studies of plantarflexor PAP. Furthermore, results reflect a rather brief contribution of the gastrocnemius potentiation to the overall plantarflexor twitch enhancements.

Time-related changes in firing rates are influenced by recruitment threshold and twitch force potentiation in the first dorsal interosseous

NEW FINDINGS

What is the central question of this study? The influences of motor unit recruitment threshold and twitch force potentiation on the changes in firing rates during steady-force muscular contractions are not well understood. What is the main finding and its importance? The behaviour of motor units during steady force was influenced by recruitment threshold, such that firing rates decreased for lower-threshold motor units but increased for higher-threshold motor units. In addition, individuals with greater changes in firing rates possessed greater twitch force potentiation. There are contradictory reports regarding changes in motor unit firing rates during steady-force contractions. Inconsistencies are likely to be the result of previous studies disregarding motor unit recruitment thresholds and not examining firing rates on a subject-by-subject basis. It is hypothesized that firing rates are manipulated by twitch force potentiation during contractions. Therefore, in this study we examined time-related changes in firing rates at steady force in relationship to motor unit recruitment threshold in the first dorsal interosseous and the influence of twitch force potentiation on such changes in young versus aged individuals. Subjects performed a 12 s steady-force contraction at 50% maximal voluntary contraction, with evoked twitches before and after the contraction to quantify potentiation. Firing rates, in relationship to recruitment thresholds, were determined at the beginning, middle and end of the steady force. There were no firing rate changes for aged individuals. For the young, firing rates decreased slightly for lower-threshold motor units but increased for higher-threshold motor units. Twitch force potentiation was greater for young than aged subjects, and changes in firing rates were correlated with twitch force potentiation. Thus, individuals with greater increases in firing rates of higher-threshold motor units and decreases in lower-threshold motor units possessed greater twitch force potentiation. Overall, changes in firing rates during brief steady-force contractions are dependent on recruitment threshold and explained in part by twitch force potentiation. Given that firing rate changes were measured in relationship to recruitment threshold, this study illustrates a more complete view of firing rate changes during steady-force contractions.

Corticospinal excitability to the biceps brachii and its relationship to postactivation potentiation of the elbow flexors

We examined the effects of a submaximal voluntary elbow flexor contraction protocol on measures of corticospinal excitability and postactivation potentiation of evoked muscle forces and if these measures were state‐dependent (rest vs. voluntary muscle contraction). Participants completed four experimental sessions where they rested or performed a 5% maximum voluntary contraction (MVC) of the elbow flexors prior to, immediately, and 5 min following a submaximal contraction protocol. During rest or 5% MVC, transcranial magnetic stimulation, transmastoid electrical stimulation, electrical stimulation of biceps brachii motor point and Erb's point were elicited to induce motor‐evoked potentials (MEPs), cervicomedullary MEPs (CMEPs), potentiated twitch (PT) force, and maximal muscle compound action potential (M_max), respectively prior to, immediately, and 5 min postcontraction protocol. MEP amplitudes increased (215 and 165%M_max, P ≤ 0.03) only at 1 and 6s postcontraction protocol, respectively during rest but not 5% MVC. CMEP amplitudes decreased during rest and 5% MVC (range:21–58%M_max, P ≤ 0.04) for up to 81 sec postcontraction protocol. Peak twitch force increased immediately postcontraction protocol and remained elevated for 90 sec (range:122–147% increase, P < 0.05). There was a significant positive correlation between MEP and PT force during rest (r = 0.88, P = 0.01) and a negative correlation between CMEP and PT force during rest (r = −0.85, P < 0.02 and 5% MVC (r = −0.96, P < 0.01) immediately postcontraction protocol. In conclusion, the change in corticospinal and spinal excitability was state‐ and time‐dependent whereas spinal excitability and postactivation potentiation were time‐dependent following the contraction protocol. Changes in corticospinal excitability and postactivation potentiation correlated and were also state‐dependent.

Age-related differences in twitch properties and muscle activation of the first dorsal interosseous

OBJECTIVE

To examine twitch force potentiation and twitch contraction duration, as well as electromyographic amplitude (EMG_RMS) and motor unit mean firing rates (MFR) at targeted forces between young and old individuals in the first dorsal interosseous (FDI). Ultrasonography was used to assess muscle quality.

METHODS

Twenty-two young (YG) (age=22.6±2.7years) and 14 older (OD) (age=62.1±4.7years) individuals completed conditioning contractions at 10% and 50% maximal voluntary contraction, (MVC) during which EMG_RMS and MFRs were assessed. Evoked twitches preceded and followed the conditioning contractions. Ultrasound images were taken to quantify muscle quality (cross-sectional area [CSA] and echo intensity [EI]).

RESULTS

No differences were found between young and old for CSA, pre-conditioning contraction twitch force, or MFRs (P>0.05). However, OD individuals exhibited greater EI and contraction duration (P<0.05), and EMG_RMS (YG=35.4±8.7%, OD=43.4±13.2%; P=0.034). Twitch force potentiation was lower for OD (0.311±0.15N) than YG (0.619±0.26N) from pre- to post-50% conditioning contraction (P<0.001).

CONCLUSIONS

Lower levels of potentiation with elongated contraction durations likely contributed to greater muscle activation during the conditioning contractions in the OD rather than altered MFRs. Ultrasonography suggested age-related changes in muscle structure contributed to altered contractile properties in the OD.

SIGNIFICANCE

Greater muscle activation requirements can have negative implications on fatigue resistance at low to moderate intensities in older individuals.

Modulation of Skeletal Muscle Contraction by Myosin Phosphorylation

The striated muscle sarcomere is a highly organized and complex enzymatic and structural organelle. Evolutionary pressures have played a vital role in determining the structure-function relationship of each protein within the sarcomere. A key part of this multimeric assembly is the light chain-binding domain (LCBD) of the myosin II motor molecule. This elongated "beam" functions as a biological lever, amplifying small interdomain movements within the myosin head into piconewton forces and nanometer displacements against the thin filament during the cross-bridge cycle. The LCBD contains two subunits known as the essential and regulatory myosin light chains (ELC and RLC, respectively). Isoformic differences in these respective species provide molecular diversity and, in addition, sites for phosphorylation of serine residues, a highly conserved feature of striated muscle systems. Work on permeabilized skeletal fibers and thick filament systems shows that the skeletal myosin light chain kinase catalyzed phosphorylation of the RLC alters the "interacting head motif" of myosin motor heads on the thick filament surface, with myriad consequences for muscle biology. At rest, structure-function changes may upregulate actomyosin ATPase activity of phosphorylated cross-bridges. During activation, these same changes may increase the Ca2+ sensitivity of force development to enhance force, work, and power output, outcomes known as "potentiation." Thus, although other mechanisms may contribute, RLC phosphorylation may represent a form of thick filament activation that provides a "molecular memory" of contraction. The clinical significance of these RLC phosphorylation mediated alterations to contractile performance of various striated muscle systems are just beginning to be understood. © 2017 American Physiological Society. Compr Physiol 7:171-212, 2017.

Acute effects of different conditioning activities on running performance of sprinters

This study investigated acute effects of different conditioning activities on sprint performance of collegiate sprinters using a randomized, crossover design. Male sprinters (N = 10; 20.1 ± 0.6 years; 174.6 ± 4.4 cm; 66.7 ± 3.5 kg; 100-m race personal best time, 11.46 ± 0.57 s; means ± SDs) performed two 60-m sprints and one of three treatments within the same day, with an interval of 2 days between the treatments. The baseline sprint was followed by one of three different conditioning activities: mini-hurdles, bounding jumps, or a free sprint. Participants then performed the post treatment sprint. In the mini-hurdle drill, the participants ran over 10 × 10 mini-hurdles (height 22 cm) as fast as possible. In the bounding jump drill, the participants performed three 60-m bounding jumps as explosively and far as possible, with 3 min intervals between trials. In the free-sprint conditioning activity, the participants performed a 60-m maximal sprint twice, with a 5 min interval between sprints. Sprint kinematics in the baseline and post treatment sprints were recorded using a high-speed camera (300 Hz). Using these films, sprint time, running velocity, step length, and step frequency were analyzed over 10 m intervals. The results of ANOVAs indicated that the mini-hurdle drill increased the maximal sprint velocity (3.2 %) and maximal step frequency (3.3 %); the other conditioning activities had no such effects. Step length did not change after any of the conditioning activities. These results suggest that conditioning activities with mini-hurdles, which require movements with a high step frequency, acutely enhances velocity during sprinting, possibly as a result of increasing step frequency.

Acute and Time-Course Effects of Traditional and Dynamic Warm-Up Routines in Young Elite Junior Tennis Players

Despite the large number of studies that have examined the acute effects of different warm up modalities (WU) on physical performance, none of them have documented the time course of potential performance recovery in tennis players. The aim of this study was twofold: (a) to analyze and compare the acute effects of two different WU modalities (traditional WU [TWU] and dynamic WU [DWU]) on physical performance (i.e., CMJ, sprint, serve speed and accuracy) in elite junior players, as well as (b) to monitor the time course of any WU-induced changes after 30 and 60 min of simulated match-play. Twelve junior elite players completed both WUs modalities (TWU and DWU) in a counterbalanced order on separate days. In each experimental session, counter movement jump (CMJ), 20-m sprint, tennis serve speed and accuracy tests were performed before (immediately after TWU or DWU) during (30 min) and after 60 min of a simulated match play. Measures were compared via four factorial (WU intervention and time) repeated measures ANOVAs. There were main effects of WU (TWU and DWU) throughout the time for all the variables analysed. The results indicate that DWU routine led to significantly faster 20 m sprint times and higher CMJs as well as faster and more accurate tennis serves at both post warm-up and 30 min match-play testing moments in comparison with the scores reported by the TWU routine (p < 0.05; positive effects with a probability of >75-99%). No significant intergroup differences were found at 60-min match-play testing moment in any variable (except for the 20 m sprint). Therefore, the findings of this study recommend for optimal performance in these elite tennis players, DWU routines should be performed prior to formal training and competition rather than TWU routines.