Postactivation Potentiation Effect Research Articles

Research on the effect of post-activation potentiation under different velocity loss thresholds on boxer's punching ability.

This study was conducted in accordance with the principles of velocity-based training theory, with the objective of investigating the effects of post-activation potentiation (PAP) induced by different velocity loss (VL) thresholds (10% vs. 20%) on the punching ability of boxers. In addition, the aim was to determine the velocity loss thresholds and time nodes that produced the optimal activation effect. Twenty-four male elite boxers were randomly assigned to three groups: CON, 10 VL, and 20 VL. All subjects in the three groups underwent an activation intervention involving an 85% of the one-repetition maximum (1RM) squat, with 6-8 repetitions performed in the CON. The number of repetitions in the 20%VL and 10 VL was determined based on the velocity loss monitored by the GymAware PowerTool system. Four time points were selected for observation: the 4th, 8th, 12th and 16th minutes. These were chosen to test the subjects' punching ability. The results demonstrated that activation training at different VL induced a post-activation potentiation in boxers, improving punching ability bilaterally and to a greater extent than in the CON. The dominant side demonstrated the greatest efficacy at the 12th minute under the 20% velocity loss threshold, while the non-dominant side exhibited the greatest efficacy at the 8th minute under the 10% velocity loss threshold.

Acute Effect of Post-activation Potentiation on Semi-dynamic Balance in Girl Gymnasts Aged 9–12

Background: Post-activation potentiation (PAP) is a novel warm-up method shown to improve sports performance. This study aimed to investigate the acute impact of this method on semi-dynamic balance while walking on the balance beam among female gymnasts aged 9–12 in Kerman city. Methods: Twenty healthy gymnasts volunteered to participate (height: 138.1±5.04 cm; mass: 40.7±3.12 kg) and were randomly divided into two equal sub-groups. The two groups attended the laboratory on two separate days, 48 hours apart. On the first day, the first sub-group performed a general warm-up (GWU), while the second sub-group performed a PAP warm-up. On the second day, the first sub-group switched to a PAP warm-up, and the second sub-group switched to a GWU. After the warm-up, the subjects took a two-minute rest, and then they walked on the balance beam while their movements were recorded using six motion analyzer cameras that captured the kinematic data of the shoulder, thigh, knee, and ankle joints. The data were processed using a low-pass Butterworth filter and analyzed using one-way ANOVA and paired t tests. Results: The results showed significant differences in shoulder, hip, knee, and ankle joint positions in proximal-distal movements following GWU and PAP warm-ups (P≤0.001). In addition, PAP caused a significant decrease in shoulder, hip, knee, and ankle joint positions in medial-lateral movements compared to GWU (P≤0.001, P≤0.001, P≤0.038, P≤0.001, respectively). Conclusion: PAP warm-up positively affects semi-dynamic balance factors in gymnasts. Given the importance of balance in gymnastics, PAP warm-up is recommended to improve sports performance.

Examining the Influence of Warm-Up Static and Dynamic Stretching, as well as Post-Activation Potentiation Effects, on the Acute Enhancement of Gymnastic Performance: A Systematic Review with Meta-Analysis.

The primary objective of this systematic review with meta-analysis is to methodically discern and compare the impact of diverse warm-up strategies, including both static and dynamic stretching, as well as post-activation potentiation techniques, on the immediate performance of gymnasts. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this paper evaluated studies that examined the gymnasts' performance after different warm-up strategies namely stretching (static [SS] or dynamic), vibration platforms (VP) or post-activation, in comparison to control conditions (e.g., mixed warm-up routines; no warm-up). The principal outcomes were centered on technical performance metrics (e.g., split, gymnastic jumps) and physical performance metrics (e.g., squat jump, countermovement jump, drop jump, balance, range of motion). Methodological assessments of the included studies were conducted using the Downs and Black Checklist. From the initial search across PubMed, Scopus, and the Web of Science databases, a total of 591 titles were retrieved, and 19 articles were ultimately incorporated in the analysis. The results revealed a non-significant differences (p > 0.05) between the SS condition and control conditions in squat jump performance, countermovement jump and gymnastic technical performance (e.g., split; split jump). Despite the difference in warm-up strategies and outcomes analyzed, the results suggest that there is no significant impairment of lower-limb power after SS. Additionally, technical elements dependent on flexibility appear to be enhanced by SS. Conversely, dynamic stretching and VP seem to be more effective for augmenting power-related and dynamic performance in gymnasts.

The Effect of Post-Activation Potentiation on Swimming Starts in Adolescent Swimmers.

Post-activation potentiation (PAP) is a phenomenon in which there is an increase in induced momentum in sporting activities after muscle contractions. In swimming, the start of the race and the increase in speed in its first few meters are important. The aim of the present study was to investigate the effect of the PAP protocol, which included a simulated body weight start on the ground, on the swimming start and on the 25 m freestyle performance. The study included 14 male and 14 female swimmers, 14.9 ± 0.6 years old. All the swimmers performed three maximal attempts of 25 m freestyle swimming from the starting block on three different days in a randomly counterbalanced order. In each session, swimmers performed either a 25 m freestyle without any intervention before the swimming trial (CG), or performed four vertical simulated ground starts at maximal effort, 15 s before (15 sG) or 8 min before (8 minG) the swimming trial. The jump height, entry distance, flight time, and flight speed for each attempt were calculated. The CG entry distance was significantly longer than that of the 15 sG and 8 minG (3.39 ± 0.20 vs. 3.31 ± 0.21 and 3.25 ± 0.25 m, respectively, p < 0.001). Four simulated swim starts on the ground, 15 s or 8 min before the swim sprint, had no positive effect on the swim start or swim performance, and it is up to the swimmer to perform these jumps.

Postactivation Potentiation for Muay Thai Kicking Performance.

Brown, L, Doyle, G, Bruce-Low, S, Domingos, S, Anthony, K, Rowan, F, and Galbraith, A. Postactivation potentiation for Muay Thai kicking performance. J Strength Cond Res 37(10): 2032-2037, 2023-The purpose of this study was to investigate the effects of postactivation potentiation (PAP) on Muay Thai kicking performance based on 3 different rest intervals. Aiming to quantify and indicate timing protocols for conditioning coaches when training athletes using PAP. 17 male (25.3 ± 3.6 years old; 179.3 ± 2.3 cm; 78.0 ± 5.2 kg), experienced Muay Thai fighters completed a standardized warm-up, including a 10-minute cycle on the Wattbike at 60 watts and 30 body mass squats for a dynamic stretch. Subjects then completed a baseline test by striking a PowerKube using the roundhouse and Teep kick techniques. PAP exercise consisted of 4 squat repetitions to maximum effort, followed by a rest period of 2, 5, or 8 minutes. Subjects then struck the PowerKube again using the roundhouse and Teep kick techniques. Rest periods were presented in a randomized order on separate days, with 72 hours between conditions. The level of significance was set at α = 0.05. Significant increases in both roundhouse (χ 2 (3) = 38.51, p < 0.05) and Teep kick (χ 2 (3) = 26.33, p < 0.05) striking power were observed when compared with baseline. For the roundhouse kick, significant differences and large effect sizes were present between all conditions except baseline and 2-minute rest. For the Teep kick, significant differences and large effect sizes were present between baseline and 5-minute rest and baseline and 8-minute rest. This indicates that PAP with 5- or 8-minute rest increased roundhouse and Teep kick power. This research reports that a PAP stimulus from a 4RM squat exercise, followed by a 5- or 8-minute rest period, enhances kick power in trained Muay Thai fighters. This technique provides a readily available, time-efficient method to enhance performance that can be built into the warm-up procedure of athletes before training or competition.

Effect of Post-Activation Potentiation according to Sequence of Velocity Using Isokinetic Device on Short-Term Performance of Lower Extremity: Taekwondo Athletes and Healthy Adults

Sang-Woo Pyun, Seong-Eun Kim, Jong-Wan Kim, Dongyeop Lee, Ji-Heon Hong, Jae-Ho Yu, Jin-Seop Kim, Hyun Suk Yang. Seong-gil Kim. J Kor Phys Ther 2022;34:298-303. https://doi.org/10.18857/jkpt.2022.34.6.298

Effect of post-activation potentiation using core activation on isometric core strength and countermovement jump variables in university male recreational athletes

Core strengthening exercises have been integrated into the conditioning regimens of sportsmen of all levels. Despite a wealth of evidence, the question of what influence core stability exercises have on jump performance remains unsolved. Only a small percentage of studies have explored effects of standalone core training. The objective of this research was to explore acute changes in countermovement jump (CMJ) performance caused by post-activation potentiation (PAP) adopting core activation exercises. 25 male recreational athletes were recruited as participants. They visited on three occasions-first for familiarisation, following for baseline data using a conventional warmup, and final for repeat data upon inducing PAP. Isometric dynamometer was used to quantify core isometric strength and CMJ variables were evaluated using a Portable performance analysis system with MARS Software. Paired t-test and multivariate analysis were carried out. All core strength metrics reported marked increase at P&lt;0.001 from conventional to PAP warmup. Following CMJ metrics varied significantly: jump height from take-off (P&lt;0.001), jump height from flight (P&lt;0.01), flight time (P&lt;0.01,) and force at free-fall (P&lt;0.001). Core training with PAP is a form of neuromuscular training that has the potential to improve power, agility, and speed by modifying force absorption, active joint stabilisation, and improved movement patterns. These alterations are ascribed to changes in cerebral drive, as well as enhanced motor-unit activation and firing frequency at the muscle level. Before a competition, a core activation warm-up can offer a unique training stimulus and increase performance via an ergogenic response. The core is essential for optimal athletic performance and should not be overlooked.

Effects of Static and Dynamic Post-Activation Potentiation Protocols on Change of Direction Performance in Adolescent Soccer Players

Summary Purpose: The study aimed to investigate the temporal effects of static and dynamic post-activation potentiation (PAP) conditioning activities on agility performance. Material and Methods: Fourteen male adolescent soccer players participated in the study. Participants performed three different conditioning activities randomly on non-consecutive days. Conditioning activities consisted of static, dynamic, and control protocols. The dynamic protocol was performed with the dynamic squat at 85% of 1-repetition maximum while the static protocol was performed 3 repetitions x 3 seconds of the isometric squat. The control protocol only completed a standardized warm-up. After the baseline measurements were taken, all protocols completed the agility test in 15th seconds, 2,4,6,8,10,12,14th minutes. Repeated measures in ANOVA were used to determine differences between PAP protocols and the Bonferroni post hoc test was employed to determine which protocol caused a significant difference. Results: There was no significant difference between protocols in baseline (p&lt;.925, ηp2 = 0.006), however, the control protocol caused a significant difference in 15th seconds and 2nd minutes compared to static and dynamic protocols (p&lt;.001, ηp2 = 0.73, 0.72, respectively). In the 4th and 6th minutes static and dynamic protocols caused a significant difference compared to control (p&lt;.001, ηp2 = 0.46-0.89, respectively), and in the 8th-minute static and dynamic protocols reached the peak performance (p&lt;.001, ηp2 = 0.96). Although in the 10-12-14th minutes static and dynamic protocols’ performance values gradually reduced. However, they always were better compared to the control protocol (p&lt;.001, ηp2 = 0.91-0.93-0.96, respectively). Conclusions: Adolescent soccer players can benefit from both static and dynamic PAP protocols before competition or halftime to improve performance.

The Effect Of Cluster-sets Resistance Priming Training On Delayed Potentiation Of Athletes

Cluster sets (CS) resistance training can induce greater post-activation potentiation (PAP) effects than traditional sets (TS) by reducing fatigue. The neuromuscular performance response demonstrated in delayed potentiation (DLP) effects is similar to that in PAP, they are all based on the relationship between potentiation and fatigue. However, it is not clear whether CS resistance training can induce greater DLP effects. OBJECTIVE The aim of the study was to compare the delayed potentiation (DLP) effects induced by cluster sets (CS) versus traditional sets (TS) resistance priming (RP) training. METHODS Sixteen male collegiate athletes were recruited for the study in a crossover design. All the subjects performed a CS (30s interval between reps, 4 minutes interval between sets) and a TS (no rest between reps, 4 minutes interval between sets) RP training sessions (3 sets of 3 repetitions of barbell back squat at 85%1RM) in random order separated by 72 hours. countermovement jump (CMJ),20-meters sprint, and T-test were evaluated at baseline and 6 hours after the RP training sessions. RESULTS 6 hours after the RP sessions, both the CS and TS significantly improved the CMJ height (CS: 50.44 ± 8.35 cm, ES = 0.48; TS: 48.35 ± 8.05 cm, ES = 0.23), CMJ take-off velocity (CS: 3.21 ± 0.28 m/s, ES = 0.56; TS: 3.16 ± 0.27 m/s, ES = 0.38), CMJ push-off impulse (CS: 237.3 ± 26.99Ns, ES = 0.38; TS: 233.8 ± 24.96Ns, ES = 0.26), 20-meters sprint (CS: 2.967 ± 0.139 s, ES = 0.85; TS: 3.007 ± 0.122 s, ES = 0.58) and T-test (CS:9.805 ± 0.535 s, ES = 0.99; TS: 9.921 ± 0.64 s, ES = 0.73) performance compared with baseline values. The CMJ peak power (64.42 ± 8.92 W/kg, ES = 0.3) were significant better following the CS compared with baseline values. The CMJ height (ES = 0.25), CMJ peak power (ES = 0.2), 20-meters sprint (ES = 0.31) were significant better following the CS compared with the TS training session. No inter-condition significant difference was observed in CMJ take-off velocity (ES = 0.18), CMJ push-off impulse (ES = 0.13), and T-test (ES = 0.2). CONCLUSIONS Compared with TS, CS RP training resulted in greater DLP effects after 6 hours, and significantly improving athletes’ lower limb speed performance and power output.

Effect of post-activation potentiation on the force, power and rate of power and force development of the upper limbs in mixed martial arts (MMA) fighters, taking into account training experience

Introduction. The aim of the study is to determine the optimal load for generating the highest value of force, power and the rate of power and force development (RFD and RPD) in the upper limb of mixed martial arts (MMA) fighters with the use of activation and explosive exercises. The training period of MMA players was included in the research. Material and Methods: Twenty-nine MMA fighters participated in the study and were divided into two groups depending on the length of their training period (under and over 5 years). The subjects did 2 ballistic push-ups before the study and after-wards they performed 5 repetitions of press dumbbells while lying down with an increasing load: 50% 1RM, 65% 1RM and 80% 1RM. The rest was 4 minutes. All ballistic push-ups were performed on ForceDecks, and the data was analysed using the manufacturer’s software. To compare differences between the groups, one-way ANOVA and post-hoc test were used. T-Student test was used to deter-mine the differences within the groups. Results: Amateurs obtained greater force and RPD results after the activation exercise performed at 50% 1RM, while power and RFD at 65% 1RM. For professionals, the highest force was achieved with a load of 80% 1RM, power at 50% 1RM, and RFD and RPD at 80% 1RM. Statistically significant differences between the groups were observed before and after each trial in force and RPD. The power did not statistically differ only after the load of 65% 1RM. In RFD, no statistically significant differences were found between the studied groups. Conclusions: Competitors with longer training experience should use a greater load in an activation exercise than competitors with shorter training experience.

Effect of postactivation potentiation and ischemic preconditioning in swimmers performance

Effect of postactivation potentiation and ischemic preconditioning in swimmers performance

Acute Effects of Post-Activation Potentiation on Explosive Strength Performance in Wrestling Athletes

Background: Researching methods of improving athlete performance has always been a topical issue. When the studies conducted in this context are examined, many different applications and methods of improving sportive performance have been tested. Especially Post-Activation Potential (PAP) is a very popular subject, and the lack of consensus among researchers on how long the rest period will be after PAP application makes this subject worth investigating. Aim: The aim of this research is to determine the most appropriate resting time interval to produce the highest explosive power after the PAP protocol. Methods: The mean age of the participants group of the research was 19,31±1,21, their height was 170,31±3,42, their weight was 69,09±4,06 and their maximal squat one repetition performance (1-RM) was 86,36±5,60. In this research, measurements were completed on five separate days with 72 hour intervals. On the first measurement day, the athletes' height and weight measurements, 1-RM squat measurements, vertical jump performance measurements were taken and explosive strength levels were calculated using the Lewis formula. On the second measurement day, 5 repetitions were performed with 85% of the 1-RM squat and after 15 seconds of rest, the vertical jump performance test was measured. On the third measurement day, 5 repetitions of 1-RM squats with 85% were performed and after 3 minutes of rest, the vertical jump performance test was measured. On the fourth measurement day, 5 repetitions of 1-RM squat with 85% were performed and after a rest period of 6 minutes, the vertical jump performance test was measured. Finally, on the fifth measurement day, 5 repetitions of 1-RM squats with 85% were performed and after 9 minutes of rest, the vertical jump performance test was measured. After all measurements, explosive strength levels were calculated using Lewis formula. Passive rest was performed between the exercise and the measurement. Results: As a result of the findings of our research, it was determined that the 15-second rest time interval after the PAP protocol negatively affected the explosive strength performance level. In addition, there was no statistically significant difference between 3 min, 6 min and 9 min rest time intervals. Conclusion: It can be said that the most appropriate resting time is between 3-9 minutes in terms of increasing the explosive strength performance of wrestlers after the PAP protocol. Keywords: PAP, wrestlers, explosive power.

Effects of postactivation potentiation on mechanical output and muscle architecture during electrically induced contractions in plantar flexors.

This study investigated the effects of postactivation potentiation (PAP) on the force output and muscle architecture in plantar flexor muscles. The mechanical response to a single electrical stimulus (twitch) and to two (doublet) and three (triplet) stimuli (10-ms interpulse interval) was measured before and after a 6-s maximal voluntary contraction (MVC). Ultrasound imaging was used to measure fascicle length and pennation angle of the gastrocnemius medialis at rest and during the electrically induced contractions. Immediately after the conditioning MVC, twitch peak force (+40%) and its maximal rate of force development (+57%) and relaxation (+62%) were greater than before the MVC (P < 0.001). The PAP extent was less for the doublet than for the twitch and for the triplet than for the doublet (P < 0.05). Whereas none of the architectural parameters changed at rest, fascicle shortening and increase in pennation angle during contractions were greater after than before the conditioning MVC, with a greater extent (P < 0.001) during the twitch (+28% and +58%, respectively) compared with the doublet (+16% and +36%) and the triplet (+12% and +14%). Overall, our results indicate that the effect of the conditioning MVC on mechanical output and muscle architecture decreased from the twitch to the triplet in plantar flexor muscles. The decreased PAP observed during doublet and triplet compared with twitch indicates that the benefit of this mechanism to the enhancement of muscle performance becomes progressively less effective during successive muscle activation.NEW & NOTEWORTHY Postactivation potentiation (PAP), a form of activity-dependent potentiation, is defined as the acute enhancement of muscle contractile properties induced by a conditioning contraction, usually a maximal voluntary contraction. The purpose of our study was to investigate the effects of PAP on force production and muscle architecture in plantar flexor (PF) muscles. The results indicate that the extent of PAP decreased from the twitch to the triplet in PF muscles. Furthermore, this study shows that fascicle shortening and the increase in pennation angle were greater after the maximal voluntary contraction for the twitch, the doublet, and the triplet, with more pronounced effects for the twitch.

The Post-Activation Potentiation Effects on Sprinting Abilities in Junior Tennis Players.

Objective: This study aimed to compare the acute effects of a full squat (SQ) or hip thrust (HT) with two different loading intensities (60% and 85% 1 RM) on sprint ability in junior male tennis players. Methods: Nineteen tennis players were included in this research. They underwent four different experimental conditions: HT at 60% 1 RM, HT at 85% 1 RM, SQ at 60% 1 RM, or SQ at 85%. The force–velocity (F–V) profile was used to assess tennis players’ sprint acceleration ability before and after applying the conditioning stimulus. The variables registered were as follows: 5 m test (5 m), 10 m test (10 m), maximum theoretical force (F0), maximum power (Pmax), and the maximal ratio of horizontal-to-resultant force (RFpeak). Results: Significant improvements in 5 m, Pmax, and RFpeak were observed when the conditioning stimulus was performing one set of seven reps of HT at 60% 1 RM. When the activation protocol was one set of seven reps of SQ at 60% 1 RM, significant improvements in 5 m, 10 m, F0, Pmax (N), and RFpeak were detected. Additionally, performing one set of three reps of SQ at 85% 1 RM as an activation protocol provided significant improvements in F0. Conclusion: The use of HT and SQ with a load of 60% 1 RM improved the sprint F–V profile components related to the acceleration phase of the sprint in junior tennis players. Using intensity loads of 85% 1 RM is not adequate to increase acute sprint performance in this population. HT presents a higher transferability to sprinting in the first 5 m of sprinting, whereas SQ provides acute improvements in different sprinting phases.

Effect of Post-Activation Potentiation on Sprint Performance after Combined Electromyostimulation and Back Squats

Post-activation potentiation (PAP) is a phenomenon which can improve force performance executed after a previous conditioning activity. PAP is usually evoked through heavy resistance, but many new methods are being suggested that acutely improve performance in post-activation potentiation protocols. The purpose of this study was to examine the effect of simultaneous application of Smith machine back squats (BS) with electromyostimulation (EMS) on sprint performance. Sixteen male (age = 22.9 ± 2.3 years, body mass = 79.9 ± 13.8 kg, BS one-repetition maximum (1 RM) = 120.5 ± 17.3) amateur football and rugby players volunteered for this study. Participants randomly performed PAP protocols (CON = no load, BS = 3 × 85% of 1 RM BS, EMS = 3 × weightless squat with electric current and BS + EMS = 3 × 85% 1 RM BS with electric current) on four different days with at least 48 h intervals. Participants rested passively for 7 min after preloads and performed the 30 m sprint test. Sprint times for 10 and 30 m were recorded for each condition. As a result, no significant difference was found in the 10 m (p = 0.13) and 30 m (p = 0.10) sprint performance between the preload protocols. The effect size was found to be trivial (ηp2: 0.13 for 10 m; ηp2: 0.11 for 30 m). In individual results, the 10 m sprint performance of five participants and 30 m sprint performance of two participants decreased in BS, EMS, or BS + EMS conditions compared with CON. No PAP effect in other participants was observed. In conclusion, preloads did not affect 10 m and 30 m sprint performance of football and rugby players. It can be said that the applied PAP protocols or physical exertion alone may cause fatigue in some individuals.

Effects of Post-Activation Potentiation (PAP) Warm-up on Vertical Jump Performance among Volleyball Players

This study aims to examine the effects of resistance versus complex exercise with the retention of post-activation potentiation (PAP) on vertical jump among volleyball players. A total of 30 volleyball players (mean age = 16.5 ± 1.106 years old) were recruited as participants of this study. The participants were requested to attend two different testing sessions, with two days between each session. Each session had a different exercise routine, namely, resistance and complex. A one-way repeated measure was used to analyse the performance of the vertical jump, while a pairwise comparison was applied to compare the retention of PAP between the resistance and complex exercises. The findings show that there is a significant interaction for both warm-up exercises; [(F(1,29)=1275.57, p=0.000] for resistance exercise and [(F(1,29) = 1456.83, p= 0.000] for complex exercise. The retention analysis for PAP effect also indicates that there is a significant difference between the two warm-up activities in vertical jump performance. In conclusion, this study reveals that both exercises managed to increase PAP among volleyball players. However, complex exercise is suggested to be combined with the warm-up method as it can maintain a longer retention than resistance exercise.

Effects of Postactivation Potentiation on Maximal Vertical Jump Performance After a Conditioning Contraction in Upper-Body and Lower-Body Muscle Groups.

Downey, RJ, Deprez, DA, and Chilibeck, PD. Effects of postactivation potentiation on maximal vertical jump performance after a conditioning contraction in upper-body and lower-body muscle groups. J Strength Cond Res 36(1): 259-261, 2022-Postactivation potentiation (PAP) involves preperformance contractions that can condition a muscle to enhance subsequent force generation and power output. Our purpose was to examine the effects of conditioning contractions that are specific or nonspecific to the target performance on PAP. Resistance-trained subjects (14 males and 10 females) performed a 7-second isometric contraction involving back squat, bench press (as conditioning contractions), or a control condition (rest) on different days in random order, before maximal vertical jump performance. The back squat as a conditioning contraction increased maximal vertical jump by 1.1 ± 3.0 cm (p < 0.05); however, the bench press as a conditioning contraction unexpectedly reduced maximal vertical jump performance by 1.4 ± 2.7 cm (p < 0.05). Conditioning contractions used to elicit a PAP response should use muscles that are specific to the performance movement. Contractions that are not biomechanically similar to the performance movement may hinder subsequent performance.

Post-Activation Potentiation Effect after Acute Plyometric Exercises on the Performance of Long Jumpers

Post-Activation Potentiation Effect after Acute Plyometric Exercises on the Performance of Long Jumpers

English

Introduction: The aim of the present study was to investigate the effects of postactivation potentiation (PAP) in vertical and horizontal jump performance in pre-pubertal children. Material and method: One hundred and nineteen children (65 girls and 54 boys; 6.8 ± 0.7 years old; 124.5 ± 6.4 cm; 25.2 ± 5.1 kg) participated in this study. This was a transversal cross-sectional study which incorporated a within-subjects repeatedmeasures design, where participants completed all protocols. The experimental procedure required four total testing, separated by one week, using a counterbalanced. This study investigated jumping performance associated with weighted jumps, lowload vertical jumps, and horizontal jumps. During two sessions the participants performed vertical jumps with and without PAP, the other two sessions the same procedures were performed for horizontal jumps. The PAP protocol consisted of one set of five weighted countermovement jumps with low-load (10% of body mass) and a rest interval of four minutes prior to the jump tests. Paired t-tests were used between conditions (PAP and control) in the vertical jump and horizontal jump test. In addition, Cohen’s d effect size and 95% confidence interval was used. Results: Significant jump height was observed in the vertical jump in the PAP condition compared to the control condition (p = 0.007). Similar results were observed for the horizontal jump tests, with significant longer distance observed in the PAP condition (p = 0.036). Conclusions: Pre-pubertal children can benefit from the effects of PAP in vertical and horizontal jumping performance when preceded by low-load ballistic movements. A protocol implementing low-loads, determined by a relative percentage of body mass is effective to promote PAP for young children.

Changes in Spinal-Reflex Excitability during Static Stretch and/or Explosive Contraction

To examine individual or combined effects of static stretch and explosive contraction on quadriceps spinal-reflex excitability (the peak Hoffmann’s reflex normalized by the peak motor-response) and the latency times of the Hoffmann’s reflex and motor-response. Fourteen healthy young males randomly experienced four conditions (stretch, contraction, stretch + contraction, and control—no intervention). For the stretch condition, three sets of a 30 s hold using the modified Thomas test on each leg were performed. For the contraction condition, three trials of maximal countermovement vertical jump were performed. Quadriceps spinal-reflex excitability and the latent period of each value on the right leg were compared at pre- and post-condition. All measurement values across conditions were not changed at any time point (condition × time) in spinal-reflex excitability (F6,143 = 1.10, p = 0.36), Hoffmann’s reflex latency (F6,143 = 0.45, p = 0.84), motor-response latency (F6,143 = 0.37, p = 0.90), and vertical jump heights (F2,65 = 1.82, p = 0.17). A statistical trend was observed in the contraction condition that spinal-reflex excitability was increased by 42% (effect size: 0.63). Neither static stretch nor explosive contraction changed the quadriceps spinal-reflex excitability, latency of Hoffmann’s reflex, and motor-response. Since our stretch protocol did not affect jumping performance and our contraction protocol induced the post-activation potentiation effect, either protocol could be used as pre-exercise activity.